Electrode plate for power storage device, and power storage device

Abstract

The disclosed electrode plate (21) for a power storage device is provided with: a long sheet-shaped current collector (22) having a first main surface (23) and a second main surface (25); and a first active material layer (27) provided on the first main surface (23). The first main surface (23) has at least one first region (R1) extending in the width direction of the current collector (22) and having a thickness of the first active material layer (27) smaller than that of the surroundings. A first active material layer (27) is provided in at least a portion of the first region (R1). As a result, the permeability of the electrolyte can be improved.

Description

Technical Field

[0001] The present disclosure relates to an electrode plate for a power storage device and a power storage device. Background Art

[0002] In the past, an electrode plate for a storage device used in a storage device such as a secondary battery is known (for example, Patent Document 1). The electrode plate for a storage device of Patent Document 1 includes a substantially rectangular collector and an active material layer provided on at least one surface of the collector, and the surface has an uncoated portion (uncoated portion) where the active material layer is not provided at one end in the width direction of a portion of the longitudinal direction of the collector. The uncoated portion includes an outer edge that coincides with a portion of the outer edge of the collector, two width-direction extending edges connected to both ends of the outer edge, and an inner edge connected to the two width-direction extending edges.

[0003] Prior Art Literature

[0004] Patent Document 1: Japanese Patent Application Publication No. 2018-206465 Summary of the invention

[0005] Problems to be solved by the invention

[0006] As shown in FIG. 3 of Patent Document 1, the active material layer is adjacent to the inner edge of the uncoated portion. In addition, in the width direction of the current collector, the size of the uncoated portion is much smaller than the size of the active material layer adjacent thereto. Therefore, in the electrode plate for the power storage device, there is a large area with the active material layer over the entire length of the current collector. If such an electrode plate for a power storage device is used to make a wound electrode body, no gaps will be generated in most of the axial regions of the electrode body, making it difficult for the electrolyte to fully penetrate. In view of such a situation, one of the purposes of the present disclosure is to improve the permeability of the electrolyte.

[0007] Means for solving problems

[0008] One aspect of the present disclosure relates to an electrode plate for a power storage device. The electrode plate for a power storage device comprises a long sheet-shaped current collector having a first main surface and a second main surface, and a first active material layer provided on the first main surface, wherein the first main surface has at least one first region extending along the width direction of the current collector and wherein the thickness of the first active material layer is smaller than that of the surrounding area, and the first active material layer is provided on at least a portion of the first region.

[0009] Another aspect of the present disclosure relates to an electric storage device including an electrode body formed by winding a first electrode plate and a second electrode plate with a separator interposed therebetween, wherein the first electrode plate is the above-mentioned electrode plate for the electric storage device.

[0010] Effects of the Invention

[0011] According to the present disclosure, the permeability of the electrolyte can be improved.

[0012] The novel features of the present invention are set forth in the appended claims, both as to structure and content, and together with other objects and features of the present application, the present invention will be better understood from the following detailed description with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a longitudinal cross-sectional view schematically showing an example of the power storage device according to the present disclosure.

[0014] Figure 2 The figures show the periphery of the first region in the positive electrode plate, (a) is a plan view, (b) is a cross-sectional view taken along line IIB-IIB, and (c) is a cross-sectional view taken along line IIC-IIC. DETAILED DESCRIPTION

[0015] The following examples are used to illustrate the embodiments of the electrode plate for a storage device and the storage device involved in the present disclosure. However, the present disclosure is not limited to the examples described below. In the following description, specific values ​​or materials are sometimes cited, but other values ​​or materials may also be applied as long as the effects of the present disclosure can be obtained.

[0016] (Electrode plates for power storage devices)

[0017] The electrode plate for a power storage device (hereinafter referred to as the electrode plate) disclosed in the present invention can be used as a positive electrode plate or a negative electrode plate of the power storage device. The electrode plate disclosed in the present invention comprises a current collector and a first active material layer. There is no particular limitation on the type of power storage device, and the following mainly takes the case of a lithium ion secondary battery as an example for explanation.

[0018] The current collector is formed into a long sheet having a first main surface and a second main surface. When used as a positive electrode current collector of a lithium ion secondary battery, the current collector can be composed of aluminum foil or aluminum alloy foil. When used as a negative electrode current collector of a lithium ion secondary battery, the current collector can be composed of copper foil or copper alloy foil.

[0019] The first active material layer is provided on the first main surface. In the case of a positive electrode active material layer of a lithium ion secondary battery, the first active material layer may contain, for example, a positive electrode active material (e.g., a transition metal oxide containing lithium), a conductive agent, and a binder. In the case of a negative electrode active material layer of a lithium ion secondary battery, the first active material layer may contain, for example, a negative electrode active material (a carbonaceous material, a silicon-containing material, etc.), a conductive agent, and a binder.

[0020] The first main surface of the current collector has at least one first region. The first region is a region extending along the width direction of the current collector and having a first active material layer having a thickness smaller than that of the surrounding region. The first active material layer is provided on at least a portion of the first region. The first region may extend over the entire length of the first main surface in the width direction of the current collector, or may extend over a portion of the first main surface. When a wound electrode body is manufactured using an electrode plate having such a first region, a gap extending in the axial direction of the electrode body is formed at the configuration portion of the first region. The permeability of the electrolyte can be improved through this gap. In addition, since the rigidity of the first region is lower than that of the surrounding region, it can be used for adjustment purposes when winding the electrode plate, and the winding can be performed with high precision.

[0021] The first region may include a first uncoated portion that is arranged at one end in the width direction of the current collector and on which the first active material layer is not provided. The first uncoated portion may be provided for mounting an electrode tab on the electrode plate. The first region of the structure includes the first uncoated portion and the first active material layer that is arranged adjacent to it and is thinner than the surrounding first active material layer. The first uncoated portion is originally a portion that does not contribute to the capacity performance of the power storage device, and it can be effectively utilized in the formation of the first region of the present disclosure. The first uncoated portion can be formed by intermittently applying a paste-like active material slurry to the first main surface.

[0022] The first uncoated portion may be mounted with the first electrode tab. In the length direction of the current collector, the length of the first uncoated portion may be greater than the length of the first electrode tab. According to such a length relationship, when a wound electrode body is manufactured, a gap extending in the axial direction of the electrode body is easily formed in at least a portion of the first uncoated portion. Thus, the permeability of the electrolyte can be further improved.

[0023] The first region may extend from one end to the other end of the current collector in the width direction in the first main surface. In this case, in a wound electrode body made using an electrode plate, a gap may be formed in the first region over the entire axial length of the electrode body. Thus, the permeability of the electrolyte may be further improved.

[0024] The minimum thickness of the first active material layer provided in the first region may be 95% or more and 99.5% or less of the maximum thickness of the first active material layer. When the minimum thickness is 95% or more of the maximum thickness, the capacity exhibited by the first active material layer in the first region can be maintained sufficiently high. When the minimum thickness is 99.5% or less of the maximum thickness, in a wound electrode body made using an electrode plate, a gap for promoting the penetration of an electrolyte can be sufficiently ensured.

[0025] The electrode plate for the storage device may also include a second active material layer disposed on the second main surface. The second main surface may have at least one second region extending along the width direction of the current collector and having a second active material layer having a thickness smaller than that of the surrounding area. The second active material layer may be disposed on at least a portion of the second region. The composition of the second active material layer may be the same as or different from that of the first active material layer. In this structure, as in the case of the first region, the permeability of the electrolyte can be improved.

[0026] The second region may include a second uncoated portion disposed at one end of the current collector in the width direction and not provided with a second active material layer. The second uncoated portion may be provided for welding an electrode tab to the first uncoated portion. The second region of the structure includes the second uncoated portion and a second active material layer disposed adjacent thereto and thinner than the surrounding second active material layer. The second uncoated portion is originally a portion that does not contribute to the capacity performance of the power storage device, and can be effectively utilized for the formation of the second region of the present disclosure.

[0027] The second region may extend from one end of the current collector in the width direction to the other end in the second main surface. In this case, in a wound electrode body made using an electrode plate, a gap may be formed in the second region over the entire axial length of the electrode body. Thus, the permeability of the electrolyte may be further improved.

[0028] The minimum thickness of the second active material layer provided in the second region may be 95% or more and 99.5% or less of the maximum thickness of the second active material layer. When the minimum thickness is 95% or more of the maximum thickness, the capacity exhibited by the second active material layer in the second region can be maintained sufficiently high. When the minimum thickness is 99.5% or less of the maximum thickness, in a wound electrode body made using an electrode plate, a gap for promoting the penetration of an electrolyte can be sufficiently ensured.

[0029] When viewed from the normal direction of the first main surface, the first region and the second region may overlap each other by at least a portion (e.g., 50% or more, 60% or more, 70% or more, 80% or more, or 90% or more). In this case, the rigidity of the portion where the first region and the second region are arranged can be reduced, so that the electrode body can be easily wound and manufactured with high precision.

[0030] (Electricity storage device)

[0031] The power storage device involved in the present disclosure may be a battery or a capacitor. The battery may be a primary battery such as a lithium primary battery, or a non-aqueous electrolyte secondary battery such as an alkaline storage battery (nickel-metal hydride battery, nickel-cadmium battery, etc.), a lithium-ion secondary battery, a lithium metal secondary battery, or an all-solid battery. The power storage device involved in the present disclosure has an electrode body.

[0032] The electrode body is formed by winding the first electrode plate and the second electrode plate with a separator between them. The outer shape of the electrode body can be, for example, cylindrical or prismatic. One of the first electrode plate and the second electrode plate is a positive electrode plate, and the other of the first electrode plate and the second electrode plate is a negative electrode plate. The first electrode plate is an electrode plate for the storage device involved in the present disclosure. The separator can be composed of a porous sheet having ion permeability and insulation. Examples of the porous sheet include thin films, woven fabrics, non-woven fabrics, etc. having micropores.

[0033] As described above, according to the present disclosure, the first region with a small thickness of the first active material layer can improve the electrolyte permeability when manufacturing a wound electrode body using an electrode plate. In addition, according to the present disclosure, the low rigidity of the first region can be utilized to wind the electrode body with high precision.

[0034] Hereinafter, an example of an electrode plate for a power storage device and a power storage device involved in the present disclosure will be specifically described with reference to the accompanying drawings. The above-mentioned components can be applied to the components of the electrode plate for a power storage device and the power storage device of the example described below. The components of the electrode plate for a power storage device and the power storage device of the example described below can be changed based on the above description. In addition, the matters described below can be applied to the above-mentioned embodiment. Regarding the components of the electrode plate for a power storage device and the power storage device of the example described below, the components that are not essential for the electrode plate for a power storage device and the power storage device involved in the present disclosure can be omitted. In addition, the drawings shown below are schematic and do not accurately reflect the actual shape or number of components.

[0035] The power storage device 10 of this embodiment is configured as a lithium ion secondary battery, but is not limited thereto. Figure 1 As shown, the power storage device 10 includes an electrode body 20 , a case 40 , a sealing body 50 , a positive electrode tab 61 , and a negative electrode tab 62 .

[0036] The electrode body 20 has a positive electrode plate 21, a negative electrode plate 29 and a separator 31. The positive electrode plate 21, the negative electrode plate 29 and the separator 31 are all in the form of long strips (or strips). The positive electrode plate 21 and the negative electrode plate 29 are wound into a spiral shape with the separator 31 sandwiched therebetween in such a way that the width direction of the long strips of positive electrode plate 21 and negative electrode plate 29 is parallel to the winding axis. The first insulating plate 71 and the second insulating plate 72 are respectively arranged on both sides of the axial direction of the electrode body 20. The positive electrode plate 21 is an example of a first electrode plate, and the negative electrode plate 29 is an example of a second electrode plate. The structure of the positive electrode plate 21 will be described in detail later.

[0037] The housing 40 is configured as one end ( Figure 1The housing 40 has an open bottomed cylindrical shape (with an upper end in the middle). The housing 40 accommodates the electrode body 20 and the electrolyte (not shown). The housing 40 has a step portion 41 formed by partially pressing the side wall of the housing 40 from the outside. The step portion 41 can be formed in a ring shape on the side wall of the housing 40 along the circumferential direction of the housing 40. In this case, the sealing body 50 can be supported on the surface of the opening side of the step portion 41.

[0038] The sealing body 50 seals the opening of the shell 40. An insulating gasket 81 is arranged between the sealing body 50 and the shell 40, thereby ensuring the airtightness of the shell 40. The sealing body 50 has a filter 51, a lower valve body 52, an insulating component 53, an upper valve body 54 and a cover 55. In the sealing body 50, these components are stacked in sequence. The sealing body 50 is installed at the opening of the shell 40 in a manner that the cover 55 is located on the outside of the shell 40 and the filter 51 is located on the inside of the shell 40. The above-mentioned components constituting the sealing body 50 are, for example, in the shape of a disc or a ring. The components except the insulating component 53 are electrically connected to each other.

[0039] The positive electrode tab 61 is mounted on the first uncoated portion 24 (described later) of the positive electrode plate 21 to electrically connect the positive electrode plate 21 to the sealing body 50. Specifically, one end of the positive electrode tab 61 is connected to the first uncoated portion 24, and the other end thereof is connected to the cover 55 of the sealing body 50. The positive electrode tab 61 passes through a through hole formed in the first insulating plate 71. Thus, the cover 55 of the sealing body 50 functions as an external positive terminal. Only one positive electrode tab 61 may be provided, or a plurality of positive electrode tabs may be provided. The positive electrode tab 61 is an example of a first electrode tab.

[0040] The negative electrode tab 62 is mounted on the negative electrode plate 29 to electrically connect the negative electrode plate 29 to the housing 40. Specifically, one end of the negative electrode tab 62 is connected to the negative electrode plate 29, and the other end is connected to the inner bottom surface of the housing 40. Thus, the housing 40 functions as an external negative electrode terminal. Only one negative electrode tab 62 may be provided, or a plurality of negative electrode tabs 62 may be provided.

[0041] Next, refer to Figure 2 , the structure of the positive electrode plate 21 is described in detail.

[0042] like Figure 2 As shown, the positive electrode plate 21 includes a long sheet-shaped current collector 22 having a first main surface 23 and a second main surface 25 , a first active material layer 27 provided on the first main surface 23 , and a second active material layer 28 provided on the second main surface.

[0043] The current collector 22 is made of, for example, aluminum foil or aluminum alloy foil. Figure 2 In the left-right direction in (a), the width direction of the current collector 22 is Figure 2(a) The longitudinal direction of the current collector 22 coincides with the winding direction of the electrode body 20 , and the width direction of the current collector 22 coincides with the axial direction of the electrode body 20 .

[0044] The first active material layer 27 includes, for example, a lithium-containing transition metal oxide, a conductive agent, a binder, etc. The second active material layer 28 has, for example, the same composition as that of the first active material layer 27 .

[0045] The first main surface 23 of the current collector 22 has a first region R1 extending along the width direction of the current collector 22 and having a first active material layer 27 having a thickness smaller than that of the surrounding area (specifically, an adjacent area in the length direction of the current collector 22). The first region R1 extends from one end to the other end in the width direction of the current collector 22 in the first main surface 23. Only one first region R1 may be provided, or a plurality of first regions R1 may be provided. The first region R1 includes a first uncoated portion 24 disposed at one end in the width direction of the current collector 22 and not provided with the first active material layer 27. The first active material layer 27 is provided in an area other than the first uncoated portion 24 in the first region R1.

[0046] On the first uncoated portion 24, for example, by welding, a Figure 2 The positive electrode tab 61 is shown by a two-dot chain line in (a). In the longitudinal direction of the current collector 22 , the length L1 of the first uncoated portion 24 is greater than the length L2 of the positive electrode tab 61 .

[0047] The minimum thickness Tmin1 of the first active material layer 27 provided in the first region R1 is not less than 95% and not more than 99.5% of the maximum thickness Tmax1 of the first active material layer 27 .

[0048] The second main surface 25 of the current collector 22 has a second region R2 extending along the width direction of the current collector 22 and having a second active material layer 28 having a thickness smaller than the surrounding (specifically, an adjacent region in the length direction of the current collector 22). The second region R2 extends from one end to the other end in the width direction of the current collector 22 in the second main surface 25. Only one second region R2 may be provided, or a plurality of second regions R2 may be provided. The second region R2 includes a second uncoated portion 26 disposed at one end in the width direction of the current collector 22 and not provided with the second active material layer 28. The second active material layer 28 is provided in the region other than the second uncoated portion 26 in the second region R2.

[0049] The minimum thickness Tmin2 of the second active material layer 28 provided in the second region R2 is equal to or greater than 95% and equal to or less than 99.5% of the maximum thickness Tmax2 of the second active material layer 28 .

[0050] The second region R2 is arranged on the back side of the first region R1. Thus, when viewed from the normal direction of the first main surface 23, the first region R1 and the second region R2 at least partially (preferably 90% or more) overlap each other.

[0051] Postscript

[0052] Based on the description of the above embodiments, the following technical solutions are disclosed.

[0053] (Technical Solution 1)

[0054] An electrode plate for a power storage device comprises a long sheet-shaped collector having a first main surface and a second main surface, and a first active material layer arranged on the first main surface, wherein the first main surface has at least one first region extending along the width direction of the collector and the thickness of the first active material layer is smaller than that of the surrounding area, and the first active material layer is arranged in at least a portion of the first region.

[0055] (Technical Solution 2)

[0056] According to the electrode plate for a power storage device according to claim 1, the first region includes a first uncoated portion which is arranged at one end in the width direction and on which the first active material layer is not provided.

[0057] (Technical Solution 3)

[0058] According to the electrode plate for a power storage device according to claim 2, a first electrode tab is attached to the first uncoated portion, and a length of the first uncoated portion in a longitudinal direction of the current collector is greater than a length of the first electrode tab.

[0059] (Technical Solution 4)

[0060] According to any one of claims 1 to 3 , the first region extends from one end in the width direction to the other end in the first main surface.

[0061] (Technical Solution 5)

[0062] According to any one of claims 1 to 4, the minimum thickness of the first active material layer provided in the first region is 95% to 99.5% of the maximum thickness of the first active material layer.

[0063] (Technical Solution 6)

[0064] According to any one of technical solutions 1 to 5, the electrode plate for a storage device also has a second active material layer arranged on the second main surface, the second main surface has at least one second region extending along the width direction and the thickness of the second active material layer is smaller than the surrounding area, and the second active material layer is arranged in at least a portion of the second region.

[0065] (Technical Solution 7)

[0066] According to the electrode plate for a power storage device according to claim 6, the second region includes a second uncoated portion which is arranged at one end in the width direction and on which the second active material layer is not provided.

[0067] (Technical Solution 8)

[0068] According to the electrode plate for a power storage device according to claim 6 or 7, the second region extends from one end to the other end in the width direction on the second main surface.

[0069] (Technical Solution 9)

[0070] According to any one of claims 6 to 8 , the minimum thickness of the second active material layer provided in the second region is 95% to 99.5% of the maximum thickness of the second active material layer.

[0071] (Technical Solution 10)

[0072] According to any one of claims 6 to 9, in the electrode plate for a power storage device, the first region and the second region at least partially overlap each other when viewed in the normal direction of the first main surface.

[0073] (Technical Solution 11)

[0074] A power storage device includes an electrode body formed by winding a first electrode plate and a second electrode plate with a separator interposed therebetween, wherein the first electrode plate is the electrode plate for a power storage device according to any one of claims 1 to 10.

[0075] The present invention has been described in conjunction with the currently 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 understand various modifications and changes. Therefore, the appended claims should be interpreted as including all modifications and changes without departing from the true spirit and scope of the present invention.

[0076] Industrial Availability

[0077] The present disclosure can be utilized for an electrode plate for a power storage device and a power storage device.

[0078] Description of Reference Numerals

[0079] 10: Power storage device

[0080] 20: Electrode body

[0081] 21: Positive plate (first electrode plate)

[0082] 22: Current collector

[0083] 23: Main side 1

[0084] 24: 1st uncoated part

[0085] 25: Second main side

[0086] 26: Second uncoated part

[0087] 27: 1st active material layer

[0088] 28: Second active material layer

[0089] 29: Negative plate (second electrode plate)

[0090] 31: Diaphragm

[0091] 40: Shell

[0092] 41: Step

[0093] 50: Sealing body

[0094] 51: Filter

[0095] 52: Lower valve body

[0096] 53: Insulation parts

[0097] 54: Upper valve body

[0098] 55: Cover

[0099] 61: Positive electrode contact (first electrode contact)

[0100] 62: Negative terminal

[0101] 71: 1st insulation board

[0102] 72: Second insulation board

[0103] 81: Gasket

[0104] L1: Length of the first uncoated portion

[0105] L2: Length of positive terminal

[0106] R1: Area 1

[0107] R2: Area 2

[0108] Tmin1: Minimum thickness of the first active material layer

[0109] Tmin2: Maximum thickness of the first active material layer

[0110] Tmax1: Minimum thickness of the second active material layer

[0111] Tmax2: Maximum thickness of the second active material layer

Claims

1. An electrode plate for a power storage device, comprising a long sheet-shaped current collector having a first main surface and a second main surface, and a first active material layer provided on the first main surface, The first main surface has at least one first region extending in the width direction of the current collector and having a first active material layer having a thickness smaller than that of surrounding regions. The first active material layer is provided in at least a portion of the first region.

2. The electrode plate for a power storage device according to claim 1, The first region includes a first uncoated portion which is disposed at one end in the width direction and on which the first active material layer is not provided.

3. The electrode plate for a power storage device according to claim 2, The first uncoated portion is provided with a first electrode contact. In the longitudinal direction of the current collector, the length of the first uncoated portion is greater than the length of the first electrode tab.

4. The electrode plate for a power storage device according to any one of claims 1 to 3, The first region extends from one end to the other end in the width direction on the first main surface.

5. The electrode plate for a power storage device according to any one of claims 1 to 3, The minimum thickness of the first active material layer provided in the first region is not less than 95% and not more than 99.5% of the maximum thickness of the first active material layer.

6. The electrode plate for a power storage device according to any one of claims 1 to 3, further comprising a second active material layer provided on the second main surface, The second main surface has at least one second region extending along the width direction and having a second active material layer having a thickness smaller than that of surrounding regions. The second active material layer is provided in at least a portion of the second region.

7. The electrode plate for a power storage device according to claim 6, The second region includes a second uncoated portion which is disposed at one end in the width direction and on which the second active material layer is not provided.

8. The electrode plate for a power storage device according to claim 6, The second region extends from one end to the other end in the width direction on the second main surface.

9. The electrode plate for a power storage device according to claim 6, The minimum thickness of the second active material layer provided in the second region is not less than 95% and not more than 99.5% of the maximum thickness of the second active material layer.

10. The electrode plate for a power storage device according to claim 6, When viewed in the normal direction of the first main surface, the first region and the second region at least partially overlap with each other.

11. A power storage device comprising an electrode body formed by winding a first electrode plate and a second electrode plate with a separator interposed therebetween, The first electrode plate is the electrode plate for a power storage device according to any one of claims 1 to 3.

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