Method of manufacturing electrode structure, and intermediary body for manufacturing electrode structure

Abstract

To provide a technology capable of restraining an extra lithium ion barrier layer from being formed.SOLUTION: A method of manufacturing an electrode structure can also include the steps of: forming a lithium ion barrier layer on the other surface of an electrode layer in a state in which an electrolyte layer is not joined to one surface of the electrode layer of a lithium ion battery; and joining a current collector, which collects electricity of the lithium ion battery, to the other surface of the electrode layer via the lithium ion barrier layer.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] Patent Document 1 discloses a current collector for a lithium-ion battery. The current collector of Patent Document 1 includes a conductive layer and a lithium-ion barrier layer disposed on the surface of the conductive layer. The current collector of Patent Document 1 is bonded to an electrode layer of the lithium-ion battery. [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 fit the size of the lithium-ion battery. At this time, excess portions that are not used as current collectors may be generated. Since the lithium-ion barrier layer is formed on the excess portions, the lithium-ion barrier layer may be wasted. Furthermore, the lithium-ion barrier layer is expensive, which may increase the manufacturing cost of the lithium-ion battery.

[0005] The present specification provides a technique that can suppress the formation of an excess lithium ion barrier layer. [Means for solving the problem]

[0006] A first aspect of the present technology relates to a method for manufacturing an electrode structure for a lithium ion battery, which may include the steps of forming a lithium ion barrier layer on one surface of an electrode layer of the lithium ion battery while an electrolyte layer is not bonded to the other surface of the electrode layer, and bonding a current collector that collects electricity from the lithium ion battery to the other surface of the electrode layer via the lithium ion barrier layer.

[0007] According to this configuration, since no electrolyte layer is bonded to one side of the electrode layer of the lithium-ion battery, handling is easy when bonding a current collector to the other side of the electrolyte layer. Furthermore, by forming a lithium-ion barrier layer on the other side of the electrode layer, the lithium-ion barrier layer can be formed only in necessary areas, and the formation of an excess lithium-ion barrier layer can be suppressed.

[0008] In a second aspect, in the first aspect, the current collector may be bonded to the other surface of the electrode layer via the lithium ion barrier layer and a carbon coating layer, and the carbon coating layer can reduce the penetration resistance of the lithium ion barrier layer.

[0009] In a third aspect, in the first or second aspect, the lithium ion barrier layer may be formed by printing, coating, spray electroless plating, or thermal spraying. This configuration allows the lithium ion barrier layer to be formed thinly.

[0010] In a fourth aspect, in any one of the first to third aspects, the step of joining the current collector to the electrode layer may include the step of pressing the current collector toward the electrode layer. With this configuration, the current collector can be firmly joined to the electrode layer.

[0011] In a fifth aspect, in any one of the first to fourth aspects, the surface roughness of the lithium ion barrier layer facing the current collector may be 0.20 to 0.40 in arithmetic mean roughness (Ra) and 2.0 to 4.0 in maximum height (Rz). This configuration allows the current collector or the carbon coating layer to be firmly bonded to the lithium ion barrier layer.

[0012] A sixth aspect of the present technology relates to an intermediate for manufacturing an electrode structure for a lithium-ion battery, which intermediate includes an electrode layer of the lithium-ion battery and a lithium-ion barrier layer formed on one surface of the electrode layer without an electrolyte layer being bonded to the other surface of the electrode layer.

[0013] According to this configuration, an electrode structure can be manufactured by joining a current collector that collects electricity from a lithium ion battery to the other side of the electrode layer via the lithium ion barrier layer of the intermediate body. According to this configuration, similar to the above, the formation of an excess lithium ion barrier layer can be suppressed. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 2 is a cross-sectional view of a lithium-ion battery and a current collector according to an embodiment. [Figure 2] 1A and 1B are cross-sectional views illustrating a method for manufacturing an electrode structure according to an embodiment of the present invention; [Figure 3] FIG. 2 is a cross-sectional view (2) illustrating the manufacturing method of the electrode structure according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0015] 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 of the embodiment 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.

[0016] 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.

[0017] 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.

[0018] 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.

[0019] Next, the current collectors 2 and 102 of the embodiment will be described. The negative electrode side current collector 2 is joined to the negative electrode layer 34 of the lithium ion battery 30 via the negative electrode side carbon coating layer 14 and the lithium ion barrier layer 12. The positive electrode side current collector 102 is joined to the positive electrode layer 32 of the lithium ion battery 30 via the positive electrode side carbon coating layer 114. The current collectors 2 and 102 have the function of collecting electricity generated in the lithium ion battery 30.

[0020] The current collectors 2, 102 are made of, for example, metal foil and are electrically conductive. The metal material of the current collectors 2, 102 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 electrical conductivity and light weight, aluminum is a preferred material for the current collectors 2, 102. The material of the current collectors 2, 102 is not particularly limited as long as it is electrically conductive, and may contain resin or the like.

[0021] One end of the negative electrode side current collector 2 is joined to the lithium ion battery 30 via the negative electrode side carbon coating layer 14 and the lithium ion barrier layer 12. The positive electrode side current collector 102 is joined to the lithium ion battery 30 via the positive electrode side carbon coating layer 114. The other end of the current collectors 2, 102 is extended to the outside and electrically connected to an external terminal (not shown). The other end of the current collectors 2, 102 and the external terminal are joined by, for example, welding. In the example shown in FIG. 1, the other end of the current collectors 2, 102 is extended in the Y direction. The current collectors 2, 102 have the function of transmitting electricity generated in the lithium ion battery 30 to the outside.

[0022] The lithium ion barrier layer 12 is provided on the lower surface 34b (surface on the current collector 2 side) of the negative electrode layer 34 of the lithium ion battery 30. The lithium ion barrier layer 12 is disposed between the negative electrode layer 34 of the lithium ion battery 30 and the current collector 2. The lithium ion barrier layer 12 is conductive. Therefore, electricity generated in the lithium ion battery 30 flows to the current collector 2 through the lithium ion barrier layer 12. In addition, the lithium ion barrier layer 12 has the function of inhibiting lithium ions in the lithium ion battery 30 from migrating from the lithium ion battery 30 to the current collector 2.

[0023] 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.

[0024] The negative electrode-side carbon coating layer 14 is provided on the upper surface 2a (the surface on the lithium ion battery 30 side) of the negative electrode-side current collector 2. The carbon coating layer 14 is disposed between the current collector 2 and the lithium ion barrier layer 12. The carbon coating layer 14 is electrically conductive. Therefore, electricity generated in the lithium ion battery 30 flows to the negative electrode-side current collector 2 through the lithium ion barrier layer 12 and the carbon coating layer 14.

[0025] The positive electrode-side carbon coating layer 114 is provided on the lower surface 102b (the surface on the lithium ion battery 30 side) of the positive electrode-side current collector 102. The carbon coating layer 114 is disposed between the current collector 102 and the lithium ion battery 30. The carbon coating layer 114 is electrically conductive. Therefore, electricity generated in the lithium ion battery 30 flows through the carbon coating layer 114 to the positive electrode-side current collector 102.

[0026] 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.

[0027] (Method of manufacturing electrode structure) Next, a manufacturing method of the electrode structure 100 will be described with reference to Figures 2 and 3. In the manufacturing method of the embodiment, first, the negative electrode layer 34 of the lithium ion battery 30 is prepared. At this stage, the negative electrode layer 34 is not bonded to the electrolyte layer 36 of the lithium ion battery 30. Therefore, the upper surface 34a of the negative electrode layer 34 is exposed to the outside. Alternatively, the upper surface 34a of the negative electrode layer 34 is covered with a member different from the electrolyte layer 36 (for example, a protective film made of resin).

[0028] Next, the lithium ion barrier layer 12 is formed on the entire lower surface 34b (surface on the current collector 2 side) of the negative electrode layer 34. The lithium ion barrier layer 12 covers the entire lower surface 34b of the negative electrode layer 34. The lithium ion barrier layer 12 is formed by, for example, printing, coating, spray-type electroless plating, or thermal spraying. 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.

[0029] 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.

[0030] As described above, the intermediate 200 is produced for producing the electrode structure 100 of the lithium ion battery 30. The intermediate 200 includes the negative electrode layer 34 of the lithium ion battery 30 and the lithium ion barrier layer 12 formed on the lower surface 34b (surface on the current collector 2 side) of the negative electrode layer 34.

[0031] The surface roughness of the lower surface 12b (surface on the current collector 2 side) of the lithium ion barrier layer 12 is not particularly limited, but may be, for example, an arithmetic mean roughness (Ra) of 0.20 to 0.40 and a maximum height (Rz) of 2.0 to 4.0. This configuration allows the current collector 2 or the carbon coating layer 14 to be firmly bonded to the lithium ion barrier layer 12. The arithmetic mean roughness (Ra) and ten-point mean roughness (Rz) are calculated, for example, based on JIS standards.

[0032] Next, the negative electrode side current collector 2 is bonded to the negative electrode layer 34. The current collector 2 is bonded to the negative electrode layer 34 via the negative electrode side carbon coating layer 14 and the lithium ion barrier layer 12. The carbon coating layer 14 is provided in advance on the upper surface 2a of the current collector 2 (the surface on the lithium ion battery 30 side). In a modified example, the carbon coating layer 14 may be provided in advance on the lower surface 12b of the lithium ion barrier layer 12 (the surface on the current collector 2 side). In another modified example, the carbon coating layer 14 may not be provided. In the step of bonding the current collector 2 to the negative electrode layer 34, the current collector 2 may be pressed toward the negative electrode layer 34. For example, the current collector 2 may be pressed using a press (not shown) while the negative electrode layer 34 is fixed.

[0033] As described above, an electrode structure 100 (see FIG. 3) for the lithium ion battery 30 is manufactured. The electrode structure 100 includes the negative electrode layer 34 of the lithium ion battery 30, the lithium ion barrier layer 12 formed on the lower surface 34b (surface on the current collector 2 side) of the negative electrode layer 34, and the current collector 2 joined to the negative electrode layer 34 via the lithium ion barrier layer 12 and the carbon coating layer 14.

[0034] Subsequently, when manufacturing a lithium ion battery 30 from the electrode structure 100, an electrolyte layer is bonded to the negative electrode layer . Also, a positive electrode layer 32 is bonded to the electrolyte layer .

[0035] Next, the positive electrode side current collector 102 is bonded to the positive electrode layer 32 (see FIG. 1). The current collector 102 is bonded to the positive electrode layer 32 via the positive electrode side carbon coating layer 114. The carbon coating layer 114 is provided in advance on the lower surface 102b of the current collector 102 (the surface on the lithium ion battery 30 side). In a modified example, the carbon coating layer 114 may be provided in advance on the upper surface of the positive electrode layer 32 (the surface on the current collector 102 side). In another modified example, the carbon coating layer 114 may not be provided. In the step of bonding the current collector 102 to the positive electrode layer 32, the current collector 102 may be pressed toward the positive electrode layer 32. For example, the current collector 102 may be pressed using a press (not shown) while the positive electrode layer 32 is fixed.

[0036] (effect) The above has described the manufacturing method of the electrode structure 100 of the embodiment. As is clear from the above description, in the manufacturing method of the embodiment, the lithium ion barrier layer 12 is formed on the lower surface 34b (an example of the other surface of the electrode layer) of the negative electrode layer 34 in a state where the electrolyte layer 36 is not joined to the upper surface 34a (an example of one surface of the electrode layer) of the negative electrode layer 34 of the lithium ion battery 30, and the current collector 2 is joined to the lower surface 34b of the negative electrode layer 34 via the lithium ion barrier layer 12.

[0037] According to this configuration, the electrolyte layer 36 is not bonded to the upper surface 34a of the negative electrode layer 34 of the lithium ion battery 30, which facilitates handling when bonding the current collector 2 to the electrolyte layer 36. Furthermore, by forming the lithium ion barrier layer 12 on the lower surface 34b of the negative electrode layer 34, the lithium ion barrier layer 12 can be formed only in necessary areas, and the formation of excess lithium ion barrier layer 12 can be prevented.

[0038] The current collector 2 is joined to the lower surface 34b of the negative electrode layer 34 via the carbon coating layer 14 and the lithium ion barrier layer 12. With this configuration, the carbon coating layer 14 can reduce the penetration resistance of the lithium ion barrier layer 12.

[0039] The lithium ion barrier layer 12 is formed by printing, coating, spray electroless plating, or thermal spraying. This configuration allows the lithium ion barrier layer 12 to be formed thinly.

[0040] The step of joining the current collector 2 to the negative electrode layer 34 includes a step of pressing the current collector 2 toward the negative electrode layer 34. With this configuration, the current collector 2 can be firmly joined to the negative electrode layer 34.

[0041] Although the embodiments have been described above, the aspects of the manufacturing method are not limited to the above embodiments. In the following description, detailed description of the same configurations as those described above may be omitted.

[0042] 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 is itself technically useful. [Explanation of symbols]

[0043] 2, 102: current collector, 12: lithium ion barrier layer, 14, 114: carbon coating layer, 30: lithium ion battery, 32: positive electrode layer, 34: negative electrode layer, 36: electrolyte layer, 100: electrode structure, 200: intermediate

Claims

1. A method for manufacturing an electrode structure of a lithium ion battery, comprising: forming a lithium ion barrier layer on one surface of the electrode layer of the lithium ion battery in a state where an electrolyte layer is not bonded to the other surface of the electrode layer; and joining a current collector that collects electricity from the lithium ion battery to the other surface of the electrode layer via the lithium ion barrier layer.

2. A method for manufacturing the electrode structure according to claim 1, the current collector is bonded to the other surface of the electrode layer via the lithium ion barrier layer and a carbon coating layer.

3. A method for manufacturing the electrode structure according to claim 1 or 2, The method for manufacturing an electrode structure, wherein the lithium ion barrier layer is formed by printing, coating, spray-type electroless plating, or thermal spraying.

4. A method for manufacturing the electrode structure according to claim 1 or 2, A method for manufacturing an electrode structure, wherein the step of joining the current collector to the electrode layer includes a step of pressing the current collector toward the electrode layer.

5. A method for manufacturing the electrode structure according to claim 1, The surface roughness of the surface of the lithium ion barrier layer facing the current collector is 0.20 to 0.40 in terms of arithmetic mean roughness (Ra) and 2.0 to 4.0 in terms of maximum height (Rz).

6. An intermediate for producing an electrode structure of a lithium ion battery, an electrode layer of the lithium ion battery; a lithium ion barrier layer formed on one surface of the electrode layer, with no electrolyte layer bonded to the other surface of the electrode layer.

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