Method for manufacturing current collector, and intermediate body for manufacturing current collector

Abstract

To provide a technique capable of suppressing wasting of a lithium ion barrier layer when manufacturing a current collector.SOLUTION: A method for manufacturing a current collector joined to an electrode of a lithium ion battery includes the steps of: preparing a conductive layer; forming a plurality of lithium ion barrier layers on a surface on the side of the lithium ion battery of the conductive layer with intervals; and removing the conductive layer between the adjacent lithium ion barrier layers.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The technology disclosed in this specification relates to a method for producing a current collector and an intermediate for producing a current collector. [Background technology]

[0002] Patent Document 1 discloses a current collector for a lithium-ion battery. The current collector in Patent Document 1 includes a conductive layer and a lithium ion barrier layer disposed on the surface of the conductive layer. The lithium ion barrier layer is disposed over the entire surface of the conductive layer. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6573312 Summary of the Invention [Problem to be solved by the invention]

[0004] When the current collector of Patent Document 1 is applied to a lithium-ion battery, it is cut to an appropriate size to match the size of the lithium-ion battery. At this time, an excess portion that is not used as a current collector may be generated. Since the lithium-ion barrier layer is formed on the excess portion, the lithium-ion barrier layer may be wasted. Because the lithium-ion barrier layer is expensive, wasting the lithium-ion barrier layer may increase the manufacturing costs of the current collector and the lithium-ion battery.

[0005] The present specification provides a technique that can prevent the lithium ion barrier layer from being wasted when producing a current collector. [Means for solving the problem]

[0006] A first aspect of the present technology relates to a method for manufacturing a current collector to be bonded to an electrode of a lithium-ion battery, which may include the steps of: preparing a conductive layer; forming a plurality of lithium-ion barrier layers at intervals on a surface of the conductive layer facing the lithium-ion battery; and removing the conductive layers between adjacent lithium-ion barrier layers.

[0007] According to this configuration, adjacent lithium ion barrier layers are formed with a gap between them, so that the area that will become the current collector can be clearly identified. Furthermore, even if the conductive layer between adjacent lithium ion barrier layers is removed during the production of the current collector, no lithium ion barrier layer is formed in that area, so that waste of the lithium ion barrier layer can be prevented.

[0008] The step of forming a plurality of lithium ion barrier layers at intervals on the surface of the conductive layer facing the lithium ion battery includes both a configuration in which a plurality of lithium ion barrier layers are directly formed on the surface of the conductive layer facing the lithium ion battery, and a configuration in which a plurality of lithium ion barrier layers are formed on the surface of the conductive layer facing the lithium ion battery via another layer.

[0009] In a second aspect, the method of the first aspect may further include a step of forming a carbon coating layer located between each of the lithium ion barrier layers and the electrode of the lithium ion battery after forming the plurality of lithium ion barrier layers.

[0010] According to this configuration, when the current collector is joined to the electrode of the lithium ion battery, the carbon coating layer penetrates into the electrode of the lithium ion battery, so that the current collector is firmly joined to the electrode of the lithium ion battery.

[0011] In a third aspect, the method of the first aspect may further include a step of forming a carbon coating layer located between the conductive layer and each of the lithium ion barrier layers before forming the plurality of lithium ion barrier layers.

[0012] According to this configuration, the carbon coating layer can be formed without the lithium ion barrier layer, so that the carbon coating layer can be formed smoothly.

[0013] In a fourth aspect, in any one of the first to third aspects, the conductive layer may be made of aluminum, which can improve the conductivity and lightness of the current collector.

[0014] In a fifth aspect, in any one of the first to fourth aspects, each of the lithium ion barrier layers may be made of nickel, which can more reliably prevent lithium ions from migrating from the electrode of the lithium ion battery to the conductive layer.

[0015] In a sixth aspect, in any one of the first to fifth aspects, the plurality of lithium ion barrier layers may be formed by printing, coating, spray electroless plating, or thermal spraying, which makes it possible to easily control the distance between adjacent lithium ion barrier layers.

[0016] A seventh aspect of the present technology relates to an intermediate for manufacturing a current collector to be bonded to an electrode of a lithium ion battery. The intermediate may include a conductive layer and a plurality of lithium ion barrier layers formed at intervals on a surface of the conductive layer facing the lithium ion battery.

[0017] According to this configuration, the current collector can be produced by removing the conductive layer between adjacent lithium ion barrier layers in the intermediate body, which, like the above, can prevent the lithium ion barrier layer from being wasted when producing the current collector. [Brief explanation of the drawings]

[0018] [Figure 1]FIG. 2 is a cross-sectional view of a lithium-ion battery and a current collector according to an embodiment. [Figure 2] 4A to 4C are cross-sectional views illustrating a method for manufacturing a current collector according to an embodiment of the present invention. [Figure 3] FIG. 2 is a perspective view illustrating a method for manufacturing a current collector according to an embodiment. [Figure 4] 10A to 10C are cross-sectional views illustrating a method for manufacturing a current collector according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0019] Before describing the manufacturing method of the embodiment, a lithium ion battery 30 and current collectors 2, 102 will first be described with reference to the drawings. As shown in FIG. 1, the lithium ion battery 30 of the embodiment includes a positive electrode layer 32, a negative electrode layer 34, and an electrolyte layer 36. The lithium ion battery 30 is joined to a negative electrode side current collector 2 and a positive electrode side current collector 102. A battery stack (not shown) is formed by stacking a plurality of lithium ion batteries 30.

[0020] The positive electrode layer 32 of the lithium-ion battery 30 is a layer containing a positive electrode active material. The positive electrode active material is not particularly limited, but examples thereof include LiMn2O4, LiCoO2, LiNiO2, and Li(Ni-Mn-Co)O2. The positive electrode layer 32 may contain one or more of these materials.

[0021] The negative electrode layer 34 is a layer containing a negative electrode active material. The negative electrode active material is not particularly limited, but examples thereof include Si, Sn, TiO, Ti2O3, TiO2, SiO, SiO2, SnO2, and Li 4 / 3 Ti 5 / 3 Examples of the negative electrode active material include O4, Li7MnN, Li-Pb alloys, and Li-Al alloys. Examples of the negative electrode active material include graphite, carbon black, activated carbon, carbon fiber, coke, soft carbon, and hard carbon. The negative electrode layer 34 may contain one or more of these materials.

[0022] The lithium ion battery 30 of this embodiment includes a solid electrolyte layer 36. The material of the electrolyte layer 36 is not particularly limited, but examples thereof include LiS-P2S5-based, LiS-SiS2-based, and LiS-B2S3-based sulfides.

[0023] Next, the current collectors 2, 102 of the embodiment will be described. The current collector 2 on the negative electrode side is joined to the negative electrode layer 34 of the lithium ion battery 30. The current collector 102 on the positive electrode side is joined to the positive electrode layer 32 of the lithium ion battery 30. The current collectors 2, 102 have the function of collecting electricity generated in the lithium ion battery 30. The current collector 2 on the negative electrode side includes a conductive layer 10, a lithium ion barrier layer 12, and a carbon coating layer 14. The current collector 102 on the positive electrode side includes a conductive layer 110 and a carbon coating layer 114.

[0024] The conductive layers 10, 110 are made of, for example, metal foil and are conductive. The metal material of the conductive layers 10, 110 is not particularly limited, but examples include aluminum (Al), gold (Au), silver (Ag), copper (Cu), iron (Fe), platinum (Pt), chromium (Cr), tin (Sn), indium (In), antimony (Sb), titanium (Ti), and alloys containing one or more of these materials. From the viewpoints of conductivity and lightness, aluminum is a preferred material for the conductive layers 10, 110. The material of the conductive layers 10, 110 is not particularly limited as long as it is conductive, and may include resin, etc.

[0025] One end of the conductive layer 10 on the negative electrode side is joined to the lithium ion battery 30 via the lithium ion barrier layer 12 and the carbon coating layer 14. One end of the conductive layer 110 on the positive electrode side is joined to the lithium ion battery 30 via the carbon coating layer 114. The other end of the conductive layers 10, 110 is extended to the outside and electrically connected to an external terminal (not shown). The other end of the conductive layers 10, 110 and the external terminal are joined by, for example, welding. In the example shown in FIG. 1 , the other end of the conductive layers 10, 110 is extended in the Y direction. The conductive layers 10, 110 have the function of transmitting electricity generated in the lithium ion battery 30 to the outside.

[0026] The lithium ion barrier layer 12 on the negative electrode side is disposed on the upper surface 10a of the conductive layer 10 (the surface on the lithium ion battery 30 side). The lithium ion barrier layer 12 is disposed between the conductive layer 10 and the negative electrode layer 34 of the lithium ion battery 30. The lithium ion barrier layer 12 is conductive. Therefore, electricity generated in the lithium ion battery 30 flows to the conductive layer 10 through the lithium ion barrier layer 12. The lithium ion barrier layer 12 also has the function of inhibiting lithium ions in the lithium ion battery 30 from migrating from the lithium ion battery 30 to the conductive layer 10.

[0027] The lithium ion barrier layer 12 is made of, for example, a material that is difficult to alloy with lithium. The material of the lithium ion barrier layer 12 is not particularly limited, but examples thereof include nickel (Ni), cobalt (Co), copper (Cu), and alloys containing one or more of these materials. From the viewpoint of suppressing the movement of lithium ions, nickel is, for example, preferable as the material of the lithium ion barrier layer 12.

[0028] The carbon coating layer 14 on the negative electrode side is disposed on the upper surface 12a of the lithium ion barrier layer 12 (the surface on the lithium ion battery 30 side). The carbon coating layer 14 is disposed between the lithium ion barrier layer 12 and the lithium ion battery 30. The carbon coating layer 14 is also disposed on the upper surface 10a of the conductive layer 10 on which the lithium ion barrier layer 12 is not formed, in a state where it covers the upper surface 12a of the lithium ion barrier layer 12. The carbon coating layer 14 also covers the upper surface 10a of the conductive layer 10 on which the lithium ion barrier layer 12 is not formed. Note that in a modified example, the carbon coating layer 14 does not have to be disposed on the upper surface 10a of the conductive layer 10 on which the lithium ion barrier layer 12 is not formed.

[0029] The carbon coating layer 14 is electrically conductive. Therefore, electricity generated in the lithium ion battery 30 flows through the carbon coating layer 14 and the lithium ion barrier layer 12 to the conductive layer 10 on the negative electrode side.

[0030] One end of the carbon coating layer 14 is joined to the lithium ion battery 30. The other end of the carbon coating layer 14 is extended to the periphery of the lithium ion battery 30. In the example shown in FIG. 1 , the other end of the carbon coating layer 14 is extended in the Y direction. Note that if the carbon coating layer 14 is not disposed on the upper surface 10a of the conductive layer 10 where the lithium ion barrier layer 12 is not present, the other end of the carbon coating layer 14 is not extended to the periphery of the lithium ion battery 30.

[0031] The positive electrode-side carbon coating layer 114 is disposed on the lower surface 110b (the surface on the lithium ion battery 30 side) of the positive electrode-side conductive layer 110. The carbon coating layer 114 is disposed between the conductive layer 110 and the lithium ion battery 30. The carbon coating layer 114 is conductive. Therefore, electricity generated in the lithium ion battery 30 flows through the carbon coating layer 114 to the positive electrode-side conductive layer 110.

[0032] The carbon coating layers 14, 114 are made of, for example, a material containing carbon. The material of the carbon coating layers 14, 114 is not particularly limited, but examples thereof include acetylene black, carbon black, vulcan, black pearl, carbon fiber, ketjen black, carbon nanotubes, carbon nanohorns, hard carbon, and fullerene. The carbon coating layers 14, 114 may contain one or more of these materials.

[0033] (Method of manufacturing a negative electrode current collector) Next, a method for manufacturing the negative electrode current collector 2 will be described with reference to Fig. 2 and Fig. 3. In the manufacturing method of this embodiment, first, the conductive layer 10 of the current collector 2 is prepared. In this embodiment, a metal foil sheet made of aluminum is used as the conductive layer 10. The conductive layer 10 has an area that is sufficiently larger than the area of ​​each lithium ion barrier layer 12.

[0034] Next, a plurality of lithium ion barrier layers 12 are formed at intervals on the upper surface 10a of the conductive layer 10 (the surface on the lithium ion battery 30 side). For example, the plurality of lithium ion barrier layers 12 are formed side by side along the X direction in the drawing. The plurality of lithium ion barrier layers 12 are spaced apart from one another. A removal region 20 is formed between adjacent lithium ion barrier layers 12. No lithium ion barrier layer 12 is formed on the upper surface 10a of the conductive layer 10 in the removal region 20.

[0035] The plurality of lithium ion barrier layers 12 are formed by, for example, printing, coating, spray electroless plating, or thermal spraying. By intermittently printing, coating, spray electroless plating, or thermal spraying the material of the lithium ion barrier layer 12, the plurality of lithium ion barrier layers 12 can be formed at intervals on the upper surface 10a of the conductive layer 10. Examples of printing include inkjet printing and screen printing. Examples of coating include gravure coating, die coating, and comma coating. Alternatively, the lithium ion barrier layer 12 may be formed by metallizing or the like.

[0036] The technologies of printing, coating, spray electroless plating, and thermal spraying are already known and will not be described in detail here. For example, inkjet printing is a technology in which fine ink droplets are tightly projected onto a substrate to form a coating. Thermal spraying is a technology in which gas heated to a temperature lower than the melting point or softening temperature of the target material is turned into a supersonic flow using a nozzle, particles of the target material are introduced into the flow and accelerated, and the target material is caused to collide with the substrate in a solid state, thereby forming a coating. Another example of metallizing is spray metallizing, which is a technology in which multiple solutions are sprayed and mixed on the substrate, causing metal to precipitate on the substrate and form a coating.

[0037] Next, as shown in FIGS. 2 and 3 , a carbon coating layer 14 is formed on the upper surfaces 12a of the plurality of lithium ion barrier layers 12. In addition, the carbon coating layer 14 is formed on the upper surface 10a of the conductive layer 10 in the removal region 20. (Note that the carbon coating layer 14 is omitted from FIG. 3 to make the drawing easier to see.) The carbon coating layer 14 covers the upper surfaces 12a of the plurality of lithium ion barrier layers 12 and the upper surface 10a of the conductive layer 10 in the removal region 20. The carbon coating layer 14 is formed across the plurality of lithium ion barrier layers 12. The carbon coating layer 14 covers the entire upper surface 12a of each lithium ion barrier layer 12.

[0038] In a modified example, multiple carbon coating layers 14 may be formed at intervals in accordance with the positions of the multiple lithium ion barrier layers 12. That is, each carbon coating layer 14 may be formed on the upper surface 12a of each lithium ion barrier layer 12. Each carbon coating layer 14 covers the entire upper surface 12a of each lithium ion barrier layer 12.

[0039] In this manner, an intermediate 200 is produced before the current collector 2 is completed. The intermediate 200 includes a conductive layer 10 and a plurality of lithium ion barrier layers 12 formed at intervals on the upper surface 10a of the conductive layer 10 (the surface on the lithium ion battery 30 side). The intermediate 200 also includes a carbon coating layer 14 formed over the upper surfaces 12a of the plurality of lithium ion barrier layers 12. In a modified example, each carbon coating layer 14 may be formed on the upper surface 12a of each lithium ion barrier layer 12.

[0040] Next, unnecessary portions are removed by cutting the intermediate 200 of the current collector 2 at predetermined positions P. Specifically, the carbon coating layer 14 and the conductive layer 10 are cut at the predetermined positions P between adjacent lithium ion barrier layers 12. For example, the carbon coating layer 14 and the conductive layer 10 are cut in the Y direction along the X-direction end 12c of each lithium ion barrier layer 12. By cutting the intermediate 200, the conductive layer 10 in the removal region 20 between adjacent lithium ion barrier layers 12 is removed. Furthermore, the carbon coating layer 14 formed in the removal region 20 is removed. Note that no lithium ion barrier layer 12 is formed on the upper surface 10a of the conductive layer 10 in the removal region 20. Therefore, the lithium ion barrier layer 12 is not removed.

[0041] As described above, the negative electrode current collector 2 is manufactured. The current collector 2 includes a conductive layer 10, a lithium ion barrier layer 12 formed on the upper surface 10a of the conductive layer 10, and a carbon coating layer 14 formed on the upper surface 12a of the lithium ion barrier layer 12. As shown in FIG. 1 , the current collector 2 is bonded to the negative electrode layer 34 of the lithium ion battery 30. The conductive layer 10 of the current collector 2 is bonded to the negative electrode layer 34 of the lithium ion battery 30 via the lithium ion barrier layer 12 and the carbon coating layer 14.

[0042] (effect) The above has described the manufacturing method of the current collector 2 of the example. As is clear from the above description, in the manufacturing method of the example, a plurality of lithium ion barrier layers 12 are formed at intervals on the upper surface 10a of the conductive layer 10, and the conductive layer 10 is removed between adjacent lithium ion barrier layers 12.

[0043] According to this configuration, adjacent lithium ion barrier layers 12 are formed with a gap between them. Therefore, even if the conductive layer 10 between adjacent lithium ion barrier layers 12 is removed when manufacturing the current collector 2, no lithium ion barrier layer 12 is formed in that portion, thereby preventing the lithium ion barrier layer 12 from being wasted.

[0044] The above manufacturing method includes a step of forming a plurality of lithium ion barrier layers 12, and then forming a carbon coating layer 14 located between each lithium ion barrier layer 12 and the negative electrode layer 34 of the lithium ion battery 30.

[0045] According to this configuration, when the current collector 2 is joined to the negative electrode layer 34 of the lithium ion battery 30, the carbon coating layer 14 penetrates into the negative electrode layer 34 of the lithium ion battery 30, so that the current collector 2 is firmly joined to the negative electrode layer 34 of the lithium ion battery 30.

[0046] Although the examples have been described above, the method for manufacturing the current collector 2 is not limited to the above examples. In the following description, detailed description of the same configurations as those described above may be omitted.

[0047] (Variation) (1) In the above example, after forming the plurality of lithium ion barrier layers 12, the carbon coating layer 14 is formed between each lithium ion barrier layer 12 and the negative electrode layer 34 of the lithium ion battery 30. However, the present invention is not limited to this configuration. In a modified example, as shown in FIG. 4, the carbon coating layer 14 may be formed between the conductive layer 10 and each lithium ion barrier layer 12 before forming the plurality of lithium ion barrier layers 12.

[0048] More specifically, after preparing the conductive layer 10, a carbon coating layer 14 is formed on the upper surface 10a of the conductive layer 10. The area of ​​the carbon coating layer 14 is sufficiently larger than the area of ​​each lithium ion barrier layer 12. The carbon coating layer 14 covers the upper surface 10a of the conductive layer 10.

[0049] Next, a plurality of lithium ion barrier layers 12 are formed at intervals on the upper surface 14a of the carbon coating layer 14. In this way, an intermediate 200 is produced before the current collector 2 is completed. The intermediate 200 includes a conductive layer 10 and a carbon coating layer 14 formed on the upper surface 10a of the conductive layer 10 (the surface on the lithium ion battery 30 side). The intermediate 200 also includes a plurality of lithium ion barrier layers 12 formed at intervals on the upper surface 14a of the carbon coating layer 14. In a modified example, a plurality of carbon coating layers 14 may be formed at intervals in accordance with the positions of the plurality of lithium ion barrier layers 12.

[0050] Next, unnecessary portions are removed by cutting the intermediate body 200 of the current collector 2 at predetermined positions P. Specifically, the carbon coating layer 14 and the conductive layer 10 are cut at predetermined positions P between adjacent lithium ion barrier layers 12. In this manner, the current collector 2 is manufactured.

[0051] According to the above configuration, by forming the carbon coating layer 14 before forming the lithium ion barrier layer 12, the carbon coating layer 14 can be formed without the lithium ion barrier layer 12, and therefore the carbon coating layer 14 can be formed smoothly.

[0052] (2) In the above embodiment, the lithium-ion battery 30 includes a solid electrolyte layer 36, but this is not limiting. In a modified example, the electrolyte of the lithium-ion battery 30 may be a liquid electrolyte. A liquid electrolyte is an electrolyte in which a lithium salt is dissolved in an organic solvent. Examples of lithium salts include Li(CF3SO2)2N, Li(C2F5SO2)2N, LiPF6, LiBF4, LiClO4, LiAsF6, LiTaF6, and LiCF3SO3.

[0053] Although specific examples of the present invention have been described in detail above, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and variations of the specific examples exemplified above. The technical elements described in this specification or drawings exhibit technical utility alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. Furthermore, the technology exemplified in this specification or drawings can achieve multiple objectives simultaneously, and achieving one of these objectives itself has technical utility. [Explanation of symbols]

[0054] 2, 102: current collector, 10, 110: conductive layer, 12: lithium ion barrier layer, 14, 114: carbon coating layer, 20: removal region, 30: lithium ion battery, 32: positive electrode layer, 34: negative electrode layer, 36: electrolyte layer, 200: intermediate

Claims

1. A method for manufacturing a current collector to be joined to an electrode of a lithium ion battery, comprising: providing a conductive layer; forming a plurality of lithium ion barrier layers at intervals on the surface of the conductive layer facing the lithium ion battery; and removing the conductive layer between adjacent lithium ion barrier layers.

2. A method for producing the current collector according to claim 1, comprising the steps of: a step of forming a plurality of the lithium ion barrier layers and then forming a carbon coating layer located between each of the lithium ion barrier layers and the electrode of the lithium ion battery.

3. A method for producing the current collector according to claim 1, comprising the steps of: a step of forming a carbon coating layer located between the conductive layer and each of the lithium ion barrier layers before forming the plurality of lithium ion barrier layers.

4. A method for producing the current collector according to claim 1, comprising the steps of: The method for producing a current collector, wherein the conductive layer is made of aluminum.

5. A method for producing the current collector according to claim 1, comprising the steps of: The method for manufacturing a current collector, wherein each of the lithium ion barrier layers is made of nickel.

6. A method for producing the current collector according to claim 1, comprising the steps of: The method for manufacturing a current collector, wherein the plurality of lithium ion barrier layers are formed by printing, coating, spray electroless plating, or thermal spraying.

7. An intermediate for producing a current collector to be bonded to an electrode of a lithium ion battery, a conductive layer; and a plurality of lithium ion barrier layers formed at intervals on the surface of the conductive layer facing the lithium ion battery.

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