Electrode plate, electrode body and battery

Abstract

The disclosed electrode plate (21) is provided with: a band-shaped core (22) having a first main surface (23) and a second main surface (24); and an active material layer (27) formed on the first main surface (23) and the second main surface (24). The core (22) has: a double-sided coated section (25) in which the active material layer (27) is formed on the first main surface (23) and the second main surface (24); and an exposed section (26) which is provided continuously with the double-sided coated section (25) and in which the active material layer (27) is not formed at least on the first main surface (23). The first main surface (23) of the exposed section (26) has an identification display section (28) formed in a region within 90% of the center in the width direction of the core (22). As a result, the recognition display unit can be formed with high precision.

Description

Technical Field

[0001] The present disclosure relates to an electrode plate, an electrode body, and a battery. Background Art

[0002] In the past, a technology for displaying information on an electrode plate of a battery is known (e.g., Patent Document 1). The electrode plate of Patent Document 1 has a strip-shaped core and active material layers formed on both sides of the core, the core has an exposed portion to which a current collecting lead is connected, and an identification display portion capable of identifying the history of a manufacturing process is formed on a part of the exposed portion.

[0003] Prior art literature

[0004] Patent Document 1: International Publication No. 2019 / 193869 Summary of the invention

[0005] However, the identification display unit of Patent Document 1 is as shown in the document, for example Figure 4 As shown, the area near the end of the exposed part (one end in the width direction of the core body) is arranged. The area near the end of the exposed part is easy to bend during the process of forming the identification display part, and it is not easy to form the identification display part with high precision in such an easy-to-bend area. Under such circumstances, one of the purposes of the present disclosure is to form the identification display part with high precision.

[0006] One aspect of the present disclosure relates to an electrode plate. The electrode plate comprises: a strip-shaped core having a first main surface and a second main surface, and an active material layer formed on the first main surface and the second main surface, the core comprising a double-sided coating portion and an exposed portion, the double-sided coating portion having the active material layer formed on the first main surface and the second main surface, the exposed portion being continuously arranged with the double-sided coating portion, and the active material layer is not formed on at least the first main surface, and an identification display portion is formed in an area within 90% of the center of the first main surface of the exposed portion in the width direction of the core.

[0007] Another aspect of the present disclosure relates to an electrode body including a first electrode plate and a second electrode plate wound with a separator interposed therebetween, wherein the first electrode plate is the above-mentioned electrode plate.

[0008] Another aspect of the present disclosure relates to a battery including the electrode assembly described above and a bottomed cylindrical outer can that houses the electrode assembly.

[0009] According to the present disclosure, the identification display portion can be formed with high precision.

[0010] Although the novel features of the present invention are described in the appended claims, the present invention in both structure and content together with other objects and features of the application will be better understood through the following detailed description with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 This is a longitudinal sectional view schematically showing the battery of Embodiment 1.

[0012] Figure 2 This is a perspective view schematically showing the electrode body according to the first embodiment.

[0013] Figure 3 is a diagram schematically showing a first electrode plate (electrode plate) according to Embodiment 1. Figure 3 (a) is a top view, Figure 3 (b) is a cross-sectional view along line III-III.

[0014] Figure 4 is a diagram schematically showing a first electrode plate (electrode plate) according to Embodiment 2. Figure 4 (a) is a top view, Figure 4 (b) is a cross-sectional view along line IV-IV.

[0015] Figure 5 is a diagram schematically showing a first electrode plate (electrode plate) according to Embodiment 3. Figure 5 (a) is a top view, Figure 5 (b) is a cross-sectional view along line VV. DETAILED DESCRIPTION

[0016] Hereinafter, embodiments of the electrode plate, electrode body, and battery disclosed herein are described by way of example. However, the present disclosure is not limited to the examples described below. In the following description, specific numerical values ​​and materials are sometimes illustrated, but other numerical values ​​and materials may also be applied as long as the effects of the present disclosure can be obtained.

[0017] (Electrode Plate)

[0018] The electrode plate of the present disclosure includes: a strip-shaped core and an active material layer. The following is an example of an electrode plate used in a non-aqueous electrolyte secondary battery (such as a lithium-ion secondary battery), but the use of the electrode plate is not limited to this. Furthermore, in the present disclosure, the scope of secondary batteries also includes a storage device (such as a lithium-ion capacitor) in which at least one of the positive electrode and the negative electrode is an electrode that exhibits capacity through a Faraday reaction.

[0019] The core has a first main surface and a second main surface. When the electrode plate is used as a positive electrode plate, the core may be, for example, a metal foil formed of aluminum, aluminum alloy, stainless steel, titanium, titanium alloy, etc. When the electrode plate is used as a negative electrode plate, the core may be, for example, a metal foil formed of copper, copper alloy, nickel, nickel alloy, etc.

[0020] The active material layer is formed on the first main surface and the second main surface of the core. When the electrode plate is used as a positive electrode plate, the active material layer is a positive electrode active material layer, and in addition to the positive electrode active material, it may also contain a conductive agent, a binder, a thickener, etc. When the electrode plate is used as a negative electrode plate, the active material layer is a negative electrode active material layer, and in addition to the negative electrode active material, it may also contain a conductive agent, a binder, a thickener, etc.

[0021] As the positive electrode active material, for example, a composite metal oxide of a transition metal such as cobalt, manganese, nickel, and lithium can be used. The positive electrode active material can be used alone or in combination of two or more. As the negative electrode active material, for example, carbon materials such as natural graphite, spherical or fibrous artificial graphite, difficult graphitization carbon (hard carbon), and easy graphitization carbon (soft carbon) can be exemplified.

[0022] As the conductive agent, carbon black such as acetylene black, ketjen black, channel black, furnace black, lamp black, thermal black, etc.; conductive fibers such as carbon fibers and metal fibers, etc. can be used. Various graphites such as natural graphite and artificial graphite can also be used as the conductive agent of the positive electrode.

[0023] As long as the binder can be dissolved or dispersed in the dispersion medium by kneading, there is no particular limitation. As the binder, for example, fluororesins, rubbers, acrylic polymers or vinyl polymers (homopolymers or copolymers of monomers such as acrylic monomers such as methyl acrylate, acrylonitrile, etc., vinyl monomers such as vinyl acetate, etc.) can be exemplified. As fluororesins, for example, polyvinylidene fluoride, copolymers of vinylidene fluoride and hexafluoropropylene, polytetrafluoroethylene, etc. can be exemplified. As rubbers, acrylic rubber, modified acrylonitrile rubber, styrene butadiene rubber (SBR), etc. can be exemplified. The binder can be used alone or in combination of two or more. In general, as the binder for the positive electrode, fluororesins are preferred, and as the binder for the negative electrode, fluororesins and rubbers are preferred.

[0024] The core body has: a double-sided coating portion, and an exposed portion continuously provided on the double-sided coating portion. The active material layer of the double-sided coating portion is formed on the first main surface and the second main surface. The exposed portion has no active material layer formed on at least the first main surface. For example, the exposed portion may be a single-sided coating portion in which no active material layer is formed on the first main surface and an active material layer is formed on the second main surface, or may be a double-sided exposed portion in which no active material layer is formed on both the first main surface and the second main surface, or may be a combination of a single-sided coating portion and a double-sided exposed portion. The exposed portion may also be arranged at one end in the long side direction of the core body.

[0025] An identification display portion is formed in an area within 90% of the center of the first main surface of the exposed portion in the width direction of the core (hereinafter also referred to as area A). It can also be said that area A is an area of ​​the first main surface of the exposed portion, excluding an area of ​​5% at one end and an area of ​​5% at the other end in the width direction of the core. Area A is not easily bent in the process of forming the identification display portion, so the identification display portion can be formed with high precision. The identification display portion can also be an identification display portion that can determine the history of the manufacturing process. The identification display portion can also be a QR code (registered trademark) as a two-dimensional code, but is not limited to this. For example, the identification display portion can be composed of numbers, characters, or a combination of numbers and characters, and can also be composed of protrusions, holes, or a combination of protrusions and holes. In addition, the identification display portion can also be a one-dimensional code such as a bar code. The identification display portion can also be formed, for example, by irradiating the first main surface of the exposed portion with a laser.

[0026] The first main surface of the exposed portion may also form an identification display portion in an area within 80% of the center, an area within 70% of the center, an area within 60% of the center, an area within 50% of the center, an area within 40% of the center, or an area within 30% of the center in the width direction of the core. Thus, the identification display portion can be formed with higher precision. Furthermore, the so-called area within X% of the center refers to a set of points that include a point in the center of the core in the width direction and are symmetrical with respect to the point in the center in the width direction of the core.

[0027] The second main surface of the exposed portion may also be formed with an active material layer at a position where the identification display portion is formed. In other words, the region in the exposed portion where the identification display portion is formed may also be the above-mentioned single-sided coating portion. In this configuration, the strength of the region where the identification display portion is formed may be increased by the active material layer formed on the second main surface. Since the region where the identification display portion is formed is more difficult to bend, the identification display portion may be formed with higher precision.

[0028] The second main surface of the exposed portion may not form an active material layer at the position where the identification display portion is formed. In other words, the area in the exposed portion where the identification display portion is formed may also be the above-mentioned two-sided exposed portion. Such a two-sided exposed portion may also be arranged at one end of the long side direction of the core body.

[0029] The identification display portion may also be formed in an area within 30% of the exposed portion near the double-sided coating portion in the long side direction of the core body (hereinafter referred to as area B). Since area B exists near the double-sided coating portion having high strength by forming active material layers on both sides, it is less likely to bend during the process of forming the identification display portion. Therefore, the identification display portion can be formed in area B with higher precision.

[0030] In the thickness direction of the core, the height dimension of the identification display part can also be smaller than the height dimension of the active material layer. In this configuration, for example, when the electrode plate interferes with other components (such as the outer can of the battery), the identification display part having a smaller height dimension than the active material layer is not easy to directly contact the other components. Thus, deformation or damage of the identification display part can be suppressed.

[0031] (Electrode body)

[0032] The electrode body disclosed in the present invention comprises: a first electrode plate and a second electrode plate which are wound with a separator. That is, the electrode body disclosed in the present invention is a wound electrode body. The first electrode plate is the above-mentioned electrode plate. The first electrode plate can be a negative electrode plate or a positive electrode plate. The separator can also be formed into a strip. The material of the separator can use a polyolefin-based material or a porous film composed of a polyolefin-based material and a heat-resistant material. As porous films of polyolefin-based materials, porous films of polyethylene, polypropylene, and ethylene-propylene copolymers can be exemplified. These resins can be used alone or in combination of two or more. Other thermoplastic polymers can also be used in combination with polyolefins as needed. As heat-resistant materials, heat-resistant resins, inorganic fillers, etc. can be cited. The porous film can be a monomer film or a multilayer film. The multilayer film can also contain a film of a mixture of a heat-resistant resin and an inorganic filler.

[0033] At the winding end portion of the electrode body, there may also be a first region where the first pole plate is wound and the second pole plate is not wound. The identification display portion may also be arranged in the first region. That is, at the winding end portion of the electrode body, the second pole plate is wound before the first region, and the identification display portion is arranged in the first region where the first pole plate and the second pole plate do not overlap. According to this configuration, even if the identification display portion formed on the first pole plate is oxidized or deformed, it will not cause an uneven reaction with the second pole plate, and the structural safety of the electrode body can be maintained.

[0034] The electrode body may also include a pair of adhesive tapes attached to the first pole plate and holding the electrode body in a wound state. The pair of adhesive tapes may also be arranged at both ends of the width direction of the first pole plate. The identification display portion may also be arranged between the pair of adhesive tapes. Since the area between the pair of adhesive tapes is not easily bent during the process of forming the identification display portion, the identification display portion can be formed with high precision. In the width direction of the first pole plate, the size of each adhesive tape may be, for example, greater than 3 mm and less than 10 mm. In the width direction of the first pole plate, the size of each adhesive tape may be, for example, greater than 5% and less than 15% of the size of the first pole plate.

[0035] In the thickness direction of the first electrode plate, the height dimension of the identification display portion may also be smaller than the height dimension of the pair of adhesive tapes. In this configuration, for example, when the electrode body interferes with other components (such as the outer can of the battery), the identification display portion having a smaller height dimension than the pair of adhesive tapes is not easy to directly contact the other components. Thus, deformation or damage of the identification display portion can be suppressed.

[0036] (Battery)

[0037] The battery disclosed in the present invention comprises: the electrode body mentioned above, and an outer can with a bottom and a cylindrical shape for housing the electrode body. The outer can may be, for example, a cylindrical shape with a bottom, or a square cylindrical shape with a bottom. The first main surface of the exposed portion of the core may also be in contact with the inner surface of the outer can. The outer can may also house a non-aqueous electrolyte together with the electrode body. The non-aqueous electrolyte may be prepared by dissolving a lithium salt in a non-aqueous solvent. Examples of the non-aqueous solvent include cyclic carbonates such as ethylene carbonate, propylene carbonate, and butylene carbonate; chain carbonates such as dimethyl carbonate and diethyl carbonate; lactones such as γ-butyrolactone, and the like. The non-aqueous solvent may be used alone or in combination of two or more.

[0038] As the lithium salt, there can be mentioned lithium salts with strong electron-withdrawing properties, such as LiPF6, LiBF4, LiClO4, LiAsF6, LiCF3SO3, LiN(SO2CF3)2, LiN(SO2C2F5)2, LiC(SO2CF3)3, etc. The lithium salt can be used alone or in combination of two or more. The concentration of the lithium salt in the non-aqueous electrolyte is, for example, 0.5 to 1.5 M, preferably 0.7 to 1.2 M.

[0039] The non-aqueous electrolyte may also contain additives as appropriate. For example, in order to form a good film on the positive and negative electrodes, vinylene carbonate (VC), cyclohexylbenzene (CHB) and their modified bodies may also be used. As additives that play a role when the non-aqueous electrolyte secondary battery becomes overcharged, for example, terphenyl, cyclohexylbenzene, diphenyl ether, etc. may also be used. The additives may be used alone or in combination of two or more. The proportion of these additives is not particularly limited, for example, it is about 0.05 to 10 weight % relative to the non-aqueous electrolyte.

[0040] As described above, according to the present disclosure, by utilizing the portion of the electrode plate that is less likely to bend, the identification display portion can be formed with high precision.

[0041] Hereinafter, an example of the electrode plate, electrode body and battery disclosed in the present invention will be specifically described with reference to the accompanying drawings. In the constituent elements of the electrode plate, electrode body and battery of the example described below, the above-mentioned constituent elements can be applied. The constituent elements of the electrode plate, electrode body and battery of the example described below can be changed based on the above description. In addition, the matters described below can also be applied to the above-mentioned embodiment. Among the constituent elements of the electrode plate, electrode body and battery of the example described below, constituent elements that are not necessary for the electrode plate, electrode body and battery disclosed in the present invention can also be omitted. Furthermore, the figures shown below are schematic diagrams and do not accurately reflect the shape and number of actual components.

[0042] Implementation Method 1

[0043] Embodiment 1 of the present disclosure will be described. The battery 10 of this embodiment is configured as a lithium ion secondary battery, but is not limited thereto. Figure 1 to Figure 3 As shown, the battery 10 includes a wound electrode assembly 20 , a bottomed cylindrical outer can 40 , and a sealing plate 50 .

[0044] The electrode assembly 20 is formed by winding the strip-shaped first electrode plate 21 and the second electrode plate 29 through the strip-shaped separator 31. In addition, the electrode assembly 20 includes two ends ( Figure 2 A pair of tapes 32 are provided to hold the electrode body 20 in a wound state (close to the upper and lower ends in the middle) and to hold the electrode body 20 in a wound state. In the present embodiment, the first electrode plate 21 is a negative electrode and the second electrode plate 29 is a positive electrode, but the present invention is not limited thereto. The first electrode plate 21 is entirely exposed at the outermost periphery of the electrode body 20, but the present invention is not limited thereto. At the outermost periphery of the electrode body 20, the first main surface 23 of the core body 22 (described later) of the first electrode plate 21 contacts the inner surface of the outer can 40.

[0045] like Figure 3 As shown, the first electrode plate 21 includes: a strip-shaped core 22 having a first main surface 23 and a second main surface 24, and a first active material layer 27 formed on the first main surface 23 and the second main surface 24. The first active material layer 27 of this embodiment is a negative electrode active material layer. The first electrode plate 21 is an example of an electrode plate, and the first active material layer 27 is an example of an active material layer.

[0046] The core 22 has a double-sided coating portion 25 and an exposed portion 26. The double-sided coating portion 25 has a first active material layer 27 formed on the first main surface 23 and the second main surface 24. The exposed portion 26 is provided continuously with the double-sided coating portion 25 and has no first active material layer 27 formed on the first main surface 23. The first active material layer 27 is formed over the entire length on the second main surface 24 of the exposed portion 26. Therefore, the first active material layer 27 is formed on the second main surface 24 of the exposed portion 26 at a position where the identification display portion 28 described later is formed. The core 22 is made of, for example, copper foil or copper alloy foil.

[0047] The first main surface 23 of the exposed portion 26 is provided with an identification display portion 28 that can identify the history of the manufacturing process in an area within 90% of the center in the width direction of the core body 22 (for example, an area within 40% of the center). Here, at the winding end portion of the electrode body 20, there is a first area 33 where the first electrode plate 21 is wound and the second electrode plate 29 is not wound. The identification display portion 28 is arranged in the first area 33. In addition, the identification display portion 28 is arranged between the pair of tapes 32. In the thickness direction ( Figure 3 In the vertical direction (b), the height dimension of the identification display portion 28 is smaller than the height dimension of the first active material layer 27 and the height dimension of the pair of tapes 32. Figure 3 In (b) , the identification display portion 28 is shown protruding from the first main surface 23 , but the identification display portion 28 may not protrude from the first main surface 23 .

[0048] Although not shown in the figure, the second pole plate 29 includes: a strip-shaped core having two main surfaces, and a second active material layer formed on the two main surfaces. The core is composed of, for example, aluminum foil or aluminum alloy foil. The second active material layer of this embodiment is a positive electrode active material layer. In this embodiment, the length dimension of the second pole plate 29 is smaller than the length dimension of the first pole plate 21, but is not limited thereto.

[0049] The outer can 40 contains the electrode body 20 and the non-aqueous electrolyte (not shown). The outer can 40 is made of metal and has one end ( Figure 1 The outer can 40 has an open bottomed cylindrical shape. A first lead 61 connected to the first electrode plate 21 is connected to the inner bottom surface of the outer can 40. Therefore, the outer can 40 of this embodiment functions as an external negative electrode terminal. A ring-shaped first insulating plate 64 is provided between the inner bottom surface of the outer can 40 and the electrode body 20.

[0050] The sealing plate 50 seals the opening of the outer can 40. A gasket 63 is arranged at the peripheral portion of the sealing plate 50, and the opening end of the outer can 40 is caulked together with the gasket 63 to seal the interior of the outer can 40. The sealing plate 50 is electrically connected to the second electrode plate 29 via the second lead 62. Therefore, the sealing plate 50 of the present embodiment functions as an external positive terminal. An annular second insulating plate 65 is provided between the sealing plate 50 and the electrode body 20.

[0051] Implementation Method 2

[0052] Embodiment 2 of the present disclosure will be described. The configuration of the first electrode plate 21 of the battery 10 of this embodiment is different from that of the above-described embodiment 1. Hereinafter, the differences from the above-described embodiment 1 will be mainly described.

[0053] like Figure 4 As shown, the first active material layer 27 is not formed on a part of the second main surface 24 of the exposed portion 26 of the first electrode 21. The identification display portion 28 is formed on the first main surface 23 on the back side of the second main surface 24 where the first active material layer 27 is not formed. In other words, at the position where the identification display portion 28 is formed, the first active material layer 27 is not formed on the second main surface 24 of the exposed portion 26. Alternatively, the identification display portion 28 is formed on the latter of the single-sided coating portion and the double-sided exposed portion of the exposed portion 26.

[0054] Implementation Method 3

[0055] Embodiment 3 of the present disclosure will be described. The configuration of the first electrode plate 21 of the battery 10 of this embodiment is different from that of the above-described embodiment 1. Hereinafter, the differences from the above-described embodiment 1 will be mainly described.

[0056] like Figure 5 As shown in FIG. 1 , the identification display portion 28 is disposed near the double-sided coating portion 25. Specifically, the identification display portion 28 is disposed in the long side direction ( Figure 5 In the left-right direction in the middle), it is formed in an area within 30% of the double-sided coating portion 25 in the exposed portion 26 (preferably within 20% of the double-sided coating portion 25).

[0057] Postscript

[0058] The following techniques are disclosed through the description of the above embodiments.

[0059] (Technology 1)

[0060] An electrode plate, comprising:

[0061] A strip-shaped core having a first main surface and a second main surface, and

[0062] active material layers formed on the first main surface and the second main surface,

[0063] The core body comprises a double-sided coating portion and an exposed portion, wherein the double-sided coating portion has the active material layer formed on the first main surface and the second main surface, and the exposed portion is continuously provided with the double-sided coating portion, and the active material layer is not formed on at least the first main surface.

[0064] An identification display portion is formed in a region within 90% of the center in the width direction of the core body on the first main surface of the exposed portion.

[0065] (Technique 2)

[0066] According to the electrode plate of the first aspect, the active material layer is formed on the second main surface of the exposed portion at a position where the identification display portion is formed.

[0067] (Technique 3)

[0068] According to the electrode plate of the first aspect, the active material layer is not formed on the second main surface of the exposed portion at a position where the identification display portion is formed.

[0069] (Technique 4)

[0070] According to the electrode plate of any one of techniques 1 to 3, the identification display portion is formed in a region within 30% of the double-sided coating portion in the exposed portion in the longitudinal direction of the core.

[0071] (Technique 5)

[0072] In the electrode plate according to any one of techniques 1 to 4, a height dimension of the identification display portion in a thickness direction of the core body is smaller than a height dimension of the active material layer.

[0073] (Technique 6)

[0074] An electrode body includes a first electrode plate and a second electrode plate which are wound with a separator interposed therebetween.

[0075] The first electrode plate is the electrode plate according to any one of techniques 1 to 5.

[0076] (Technique 7)

[0077] According to the electrode body of the sixth aspect, at the winding end portion of the electrode body, there is a first region where the first electrode plate is wound and the second electrode plate is not wound,

[0078] The identification display unit is arranged in the first area.

[0079] (Technology 8)

[0080] The electrode assembly according to the sixth or seventh aspect further comprises a pair of adhesive tapes, the pair of adhesive tapes being attached to the first electrode plate and holding the electrode assembly in a wound state.

[0081] The pair of adhesive tapes are arranged in regions close to both ends in the width direction of the first electrode plate.

[0082] The identification display portion is disposed between the pair of adhesive tapes.

[0083] (Technique 9)

[0084] In the electrode assembly according to the eighth aspect, the height dimension of the identification display portion in the thickness direction of the first electrode plate is smaller than the height dimension of the pair of tapes.

[0085] (Technology 10)

[0086] A battery having:

[0087] The electrode body according to any one of Techniques 6 to 9, and

[0088] A bottomed cylindrical outer can accommodates the electrode assembly.

[0089] The present invention has been described by the present preferred embodiments, but this disclosure should not be interpreted as limiting. By reading the above disclosure, a person of ordinary skill in the art to which the present invention belongs can clearly know various modifications and changes without doubt. Therefore, the attached claims should be interpreted as including all modifications and changes without departing from the true spirit and scope of the present disclosure.

[0090] Industrial Applicability

[0091] The present disclosure can be utilized in an electrode plate, an electrode body, and a battery.

[0092] Description of Reference Numerals

[0093] 10: Battery

[0094] 20: Electrode body

[0095] 21: 1st plate (electrode plate)

[0096] 22: Core

[0097] 23: Main side 1

[0098] 24: Second main side

[0099] 25: Double-sided coating

[0100] 26: Exposed part

[0101] 27: First active material layer (active material layer)

[0102] 28: Identification display unit

[0103] 29: Second plate

[0104] 31: Diaphragm

[0105] 32: Tape

[0106] 33: Area 1

[0107] 40: External can

[0108] 50: Sealing plate

[0109] 61: First lead

[0110] 62: Second lead

[0111] 63: Gasket

[0112] 64: 1st insulation board

[0113] 65: Second insulation board

Claims

1. An electrode plate, comprising: A strip-shaped core having a first main surface and a second main surface, and active material layers formed on the first main surface and the second main surface, The core body comprises a double-sided coating portion and an exposed portion, wherein the double-sided coating portion has the active material layer formed on the first main surface and the second main surface, and the exposed portion is continuously provided with the double-sided coating portion, and the active material layer is not formed on at least the first main surface. An identification display portion is formed in a region within 90% of the center in the width direction of the core body on the first main surface of the exposed portion. 2 . The electrode plate according to claim 1 , wherein the active material layer is formed on the second main surface of the exposed portion at a position where the identification display portion is formed. 3 . The electrode plate according to claim 1 , wherein the active material layer is not formed on the second main surface of the exposed portion at a position where the identification display portion is formed. 4 . The electrode plate according to claim 1 , wherein the identification display portion is formed in a region within 30% of the double-sided coating portion of the exposed portion in the longitudinal direction of the core body. 5 . The electrode plate according to claim 1 , wherein a height dimension of the identification display portion in a thickness direction of the core body is smaller than a height dimension of the active material layer.

6. An electrode body comprising a first electrode plate and a second electrode plate wound with a separator interposed therebetween, The first electrode plate is the electrode plate according to any one of claims 1 to 3.

7. The electrode body according to claim 6, At the winding end portion of the electrode body, there is a first region where the first electrode plate is wound and the second electrode plate is not wound, The identification display unit is arranged in the first area.

8. The electrode body according to claim 6, A pair of adhesive tapes is further provided, wherein the pair of adhesive tapes are attached to the first electrode plate to hold the electrode body in a wound state. The pair of adhesive tapes are arranged in regions close to both ends in the width direction of the first electrode plate. The identification display portion is disposed between the pair of adhesive tapes. 9 . The electrode assembly according to claim 8 , wherein a height dimension of the identification display portion in a thickness direction of the first electrode plate is smaller than a height dimension of the pair of tapes.

10. A battery comprising: The electrode body according to claim 6, and A bottomed cylindrical outer can accommodates the electrode assembly.

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