JP2019102196A - Manufacturing method of battery - Google Patents

Abstract

To provide a manufacturing method of a battery which prevents short-circuiting of the battery and improves material yield.SOLUTION: A manufacturing method of a battery includes the steps of: forming a coated part which is coated with a first active material layer and a non-coated part which is not coated with the first active material layer, by coating a top of a collector with the first active material layer in an intermittent manner; coating a top of the coated part with an electrolyte layer; coating a top of the electrolyte later inside of an end of the electrolyte layer with a second active material layer; cutting the collector in the non-coated part; and using the non-coated part to form a current extraction tab.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method of manufacturing a battery.

  The secondary battery includes a laminated electrode body in which an electrode plate having a positive electrode active material coated on both sides of a current collector and an electrode plate having a negative electrode active material coated are laminated via a separator. As a manufacturing method of the electrode plate which comprises a lamination | stacking electrode body, the method of coating an active material intermittently on both surfaces of a strip shaped collector is proposed (for example, patent documents 1-3). The current collector is cut in the uncoated area where the active material is not coated, and a tab for current extraction is formed on the uncoated area of each of the cut members.

  Further, Patent Document 4 discloses a technology in which two layers of an active material and a conductor are simultaneously coated to alternately form the active material and the conductor in a stripe shape in the horizontal direction. The electrode coating film composed of the active material and the conductor is continuously formed on the electrode substrate.

  In recent years, an all solid battery in which an electrolyte solution is replaced with a solid electrolyte such as a sulfide-based solid electrolyte or an oxide-based solid electrolyte has attracted attention. Compared to a secondary battery using an electrolytic solution, the all solid battery using no electrolytic solution has high cycle durability and energy density without causing decomposition or the like of the electrolytic solution caused by overcharging of the battery. There is.

  Such an all-solid-state battery includes a battery laminate in which a positive electrode active material layer, a solid electrolyte layer, and a negative electrode active material layer are stacked. In this battery laminate, the positive electrode active material layer and the negative electrode active material layer may be in contact with each other to cause a short circuit due to deformation due to processing such as cutting or damage due to vibration during use.

  Then, the technique which provides a difference in the magnitude | size of a positive electrode active material layer and a negative electrode active material layer, and suppresses a short circuit is proposed (for example, patent document 5). In Patent Document 5, the periphery of the active material layer is maintained while the solid electrolyte layer is maintained by irradiating a laser from the side of the active material layer to the battery stack in which the active material layer and the solid electrolyte layer are stacked. It is removing.

Japanese Patent Application Laid-Open No. 11-354110 International Publication No. 2013/031889 Unexamined-Japanese-Patent No. 2007-329050 JP, 2014-229479, A JP, 2016-213070, A

  In the case of producing a battery laminate in which the positive electrode active material layer is smaller than the negative electrode active material layer in order to prevent a short circuit of the all solid battery, first, the peripheral portion of the stacked positive electrode active material layer is framed. A groove in which the positive electrode active material layer is removed by laser is formed. Then, the battery laminate is cut out by cutting along the grooves so that the negative electrode active material layer is larger than the positive electrode active material layer. Since the unnecessary part after the battery laminate is cut out is discarded, the yield of the material is deteriorated.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a method of manufacturing a battery in which the material yield is improved while preventing the short circuit of the battery.

  In the method of manufacturing a battery according to one aspect of the present invention, a first active material layer is intermittently applied on a current collector, and a coated portion on which the first active material layer is applied; A step of forming an uncoated portion on which the first active material layer is not coated, a step of applying an electrolyte layer on the coated portion, and an end portion of the electrolyte layer on the electrolyte layer A step of coating the second active material layer on the inside, a step of cutting the current collector in the uncoated portion, and a step of forming a tab for current extraction using the uncoated portion Prepare.

  ADVANTAGE OF THE INVENTION According to this invention, while preventing the short circuit of a battery, the manufacturing method of the battery which improved material yield can be provided.

FIG. 6 is a manufacturing process diagram illustrating the method of manufacturing a battery in accordance with Embodiment 1. FIG. 6 is a manufacturing process diagram illustrating the method of manufacturing a battery in accordance with Embodiment 1. FIG. 7 is a manufacturing process diagram illustrating a method of manufacturing a battery according to Embodiment 2. It is a manufacturing-process figure explaining the manufacturing method of the battery of a comparative example. It is a manufacturing-process figure explaining the manufacturing method of the battery of a comparative example. It is a manufacturing-process figure explaining the manufacturing method of the battery of a comparative example.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The same reference numerals are given to the same components in the respective drawings, and the overlapping description will be omitted.

  The present invention relates to a method of manufacturing a laminated all solid state battery. The all-solid-state battery includes a battery laminate in which a positive electrode active material layer, a solid electrolyte layer, and a negative electrode active material layer are stacked. One of the positive electrode active material layer and the negative electrode active material layer corresponds to the first active material layer described in the claims, and the other corresponds to the second active material layer. A solid electrolyte layer is disposed between the positive electrode active material layer and the negative electrode active material layer. The manufacturing method according to the embodiment intermittently applies the first active material layer and the electrolyte layer, and forms the second active material layer one size smaller than the electrolyte layer on the electrolyte layer, so that the short circuit of the battery is achieved. While preventing, it is possible to improve the material yield.

Embodiment 1
1 and 2 are manufacturing process diagrams illustrating the method of manufacturing a battery according to the first embodiment. The flow of each process is shown in the upper part in FIG. 1, 2, and the state of the battery laminated body in each process is shown in the lower part. The battery laminate P obtained by the manufacturing method of FIG. 1 has a configuration in which the negative electrode active material layer 11, the solid electrolyte layer 12, and the positive electrode active material layer 13 are stacked on the negative electrode foil 10.

  It is preferable that it is order of the negative electrode active material layer 11, the solid electrolyte layer 12, and the positive electrode active material layer 13 in order of a lamination | stacking order of each layer of battery laminated body P sequentially from the bottom. This is because the positive electrode active material layer 13 is more easily cracked than the negative electrode active material layer 11, and therefore, the purpose is to suppress the generation of the crack. Note that the negative electrode active material layer 11 and the positive electrode active material layer 13 can be replaced with each other. In the following embodiment, the negative electrode active material layer 11 is a first active material layer, and the positive electrode active material layer 13 is a second active material layer. After the battery laminate P is cut out from the strip-shaped negative electrode foil 10, the positive electrode foil 14 is attached onto the positive electrode active material layer 13.

  The negative electrode foil 10 is a current collector for the negative electrode active material layer 11. As the negative electrode foil 10, a metal foil, for example, a SUS foil or a Cu foil can be used. As a positive electrode foil which is a current collector for the positive electrode active material layer 13, a metal foil, for example, a SUS foil or an Al foil can be used. The positive electrode foil and the negative electrode foil are connected to a positive electrode terminal and a negative electrode terminal (not shown) leading to the outside, respectively, by a tab for current extraction.

  As a negative electrode active material contained in the negative electrode active material layer 11, a material capable of inserting Li, for example, a carbon-based negative electrode active material such as graphite can be used. Moreover, as a solid electrolyte contained in the negative electrode active material layer 11, arbitrary solid electrolytes, such as a sulfide solid electrolyte and an oxide electrolyte, can be used. In addition, the negative electrode active material layer 11 may contain any binder, conductive auxiliary agent, and the like.

  As a positive electrode active material contained in the positive electrode active material layer 13, a material capable of inserting Li, for example, as a solid electrolyte contained in the positive electrode active material layer 13, any solid such as a sulfide solid electrolyte or an oxide electrolyte An electrolyte can be used. In addition, the positive electrode active material layer 13 may contain any binder, conductive additive and the like.

  The solid electrolyte used for the solid electrolyte layer 12 is not particularly limited. For example, a sulfide solid electrolyte or an oxide solid electrolyte applied to the negative electrode active material layer 11 and the positive electrode active material layer 13 can be used.

  As shown in FIG. 1, in the method of manufacturing the battery of Embodiment 1, a negative electrode coating step (S11) of coating the negative electrode active material layer 11 and an electrolyte coating step of coating the solid electrolyte layer 12 (S12) A negative electrode pressing step (S13), a transfer step (S14) for applying the positive electrode active material layer 13 by transfer, a densification pressing step (S15), a sheet cutting step (S16) for cutting the negative electrode foil 10, a laminate for a battery Cutting step (S17) for cutting out

  In FIG. 1, the arrows indicate the flow direction of the negative electrode foil 10. As shown in FIG. 1, a plurality of substantially rectangular battery laminates P are continuously formed on the flowing strip-like negative electrode foil 10. In the example shown in FIG. 1, the longitudinal direction of the battery laminate P is formed along the length direction of the strip-like negative electrode foil 10, and the short direction of the battery laminate P is in the width direction of the strip-like negative electrode foil 10. It is formed along. The tab T for current extraction is disposed on the downstream side in the flow direction of the battery stack P. Such arrangement of the battery laminate P on the negative electrode foil 10 is referred to as vertical orientation.

  First, in the negative electrode coating step (S11), the negative electrode active material layer 11 is coated on both surfaces of the negative electrode foil 10. The negative electrode active material layer 11 is prepared, for example, by adding a solvent to a negative electrode active material, a conductive auxiliary agent, a binder, etc. and mixing them to obtain a slurry, and coating the slurry on the negative electrode foil 10 and drying it. . Although the coating method of the negative electrode active material layer 11 is not particularly limited, for example, a bar coating method, a die coating method, a screen coating method, an inkjet coating method, or the like can be used. The negative electrode active material layer 11 is intermittently applied to both surfaces of the negative electrode foil 10. Thereby, on the negative electrode foil 10, the coated part in which the negative electrode active material layer 11 was coated, and the uncoated part in which the negative electrode active material layer 11 is not coated are formed.

  Next, in the electrolyte coating step (S12), the solid electrolyte layer 12 is formed on the negative electrode active material layer 11 formed on both sides of the negative electrode foil 10, respectively. Then, in the negative electrode pressing step (S13), the negative electrode active material layer 11 and the solid electrolyte layer 12 are pressed by the first pressing mechanism 20 in order to enhance the input / output performance of the battery. The first pressing mechanism 20 is, for example, a roll-type pressing unit, and has a plurality of rotatable pressing rollers (in the present embodiment, two upper and lower rollers).

  Then, the positive electrode active material layer 13 is coated on the solid electrolyte layer 12 (S14). The positive electrode active material layer 13 is formed inside the end of the solid electrolyte layer 12. That is, the positive electrode active material layer 13 is disposed so as to be slightly smaller than the peripheral edge of the solid electrolyte layer 12 and not to protrude from the periphery of the solid electrolyte layer 12.

  The positive electrode active material layer 13 is prepared, for example, by adding a solvent to a positive electrode active material, a conductive auxiliary agent, a binder, etc. and mixing them to obtain a slurry, coating the slurry on the solid electrolyte layer 12 and drying it. Ru. In the example shown in FIG. 1, the positive electrode active material layer 13 is transfer-coated on the solid electrolyte layer 12 by the transfer mechanism 30.

  A plurality of thin film-like positive electrode active material layers 13 which are slightly smaller than the solid electrolyte layer 12 are continuously formed on the strip-like substrate having film-like flexibility. Both ends of the substrate are connected to the supply roller 31 and the winding roller 33, respectively. The substrate on which the positive electrode active material layer 13 is formed is in a state of being wound around the supply roller 31. The feed roller 31, the transfer roller 32, and the take-up roller 33 are rotatable about an axis extending in the longitudinal direction.

  The positive electrode active material layer 13 is fed out from the supply roller 31 by the rotation of the supply roller 31 and the winding roller 33, guided by the transfer roller 32, and laminated on the solid electrolyte layer 12. The substrate on which the positive electrode active material layer 13 has been transferred is taken up by the transfer roller 32. In addition, the coating method of the positive electrode active material layer 13 is not specifically limited, It is also possible to employ | adopt any of the coating method mentioned above.

  Thereafter, in the densifying pressing step (S15), the negative electrode active material layer 11, the solid electrolyte layer 12, and the positive electrode active material layer 13 stacked by the second pressing mechanism 40 are pressed in the stacking direction to densify each layer. The second pressing mechanism 40 is, for example, a roll-type pressing unit, and has a plurality of rotatable pressing rollers (in the present embodiment, two upper and lower rollers).

  Then, in the uncoated portion of the negative electrode foil 10, the negative electrode foil 10 is cut (S16). Thereby, the laminated sheet W in which the negative electrode active material layer 11, the solid electrolyte layer 12, and the positive electrode active material layer 13 are laminated on both surfaces of the negative electrode foil 10 is obtained. Thereafter, the uncoated portion included in the laminate sheet W is cut to form a tab T for current extraction (S17). In this manner, a single-layered battery laminate P is obtained.

  Thereafter, as shown in FIG. 2, assembly of the all-solid-state battery is performed using the single-sheet battery laminate P. In the method of manufacturing a battery according to the first embodiment, an end insulation step (S21), a positive electrode foil cutting step (S22), a first foil bonding step (S23), a laminating step (S24), and a second foil bonding step (S25), further including a terminal welding step (S26) and a sealing step (S27).

  In the end insulation step (S21), the tab T is coated with a hot melt such as a thermoplastic resin. Thereby, the insulation of the tab T is secured, and when stacking the battery stack P, it is possible to prevent the occurrence of a short circuit between the electrodes of the tab T that are stacked. In addition, in the positive electrode foil cutting step (S22), the positive electrode foil 14 is cut out from the positive electrode foil sheet according to the shape of the battery laminate P. Hot melt is applied to one side of the positive electrode foil 14.

  Then, the positive electrode foil 14 coated with hot melt on one side is attached onto the positive electrode active material layer 13 of the battery laminate P (S23). Thereafter, the battery laminate P after the positive electrode foil 14 is attached is inverted, and the positive electrode foil 14 of the already inverted battery laminate P is not attached with the surface on which the positive electrode foil 14 is attached facing down. The surface is laminated on the positive electrode active material layer 13 (S24). The process from S21 to S24 is repeated to stack a predetermined number of battery stacks P.

  After laminating a predetermined number of battery laminates P, the positive electrode foil 14 is attached onto the uppermost positive electrode active material layer 13 (S25). Then, the end portions of the positive electrode and the negative electrode are welded (S26), and vacuum sealing is performed in a battery case such as a laminate film (S27), whereby the laminated all solid battery F can be manufactured. Note that this assembly procedure is an example, and the laminated all-solid battery F can be manufactured by other procedures.

  Here, the comparative example will be described with reference to FIGS. 4 to 6 are manufacturing process diagrams illustrating a method of manufacturing the battery of the comparative example. In FIG. 4, the flow of each process is shown in the upper part, and the state of the battery stack during each process is shown in the lower part.

  As shown in FIG. 4, in the manufacturing method of the comparative example, a negative electrode coating step (S1) of coating the negative electrode active material layer 11, an electrolyte coating step of coating the solid electrolyte layer 12 (S2), a negative electrode pressing step (S3), including a transfer step (S4) for applying the positive electrode active material layer 13 by transfer, a densification press step (S5), a positive electrode removal step (S6), and a cutting step (S7) for cutting out the battery laminate .

In the comparative example, unlike the negative electrode coating step (S11) of the first embodiment described above, the longitudinal direction of the battery laminate P is formed along the width direction of the strip-like negative electrode foil 10 The short side direction is formed along the length direction of the strip-like negative electrode foil 10. At one end side of the negative electrode foil 10, an uncoated portion extending in the length direction is formed. A tab for current extraction is formed on this uncoated portion. That is, the tabs T are arranged side by side with the battery stack P in the width direction.
Such arrangement of the battery laminate P on the negative electrode foil 10 is referred to as horizontal orientation.

  The negative electrode active material layer 11 is continuously coated on the negative electrode foil 10 (S1). Also, the solid electrolyte layer 12 is continuously formed on the continuously formed negative electrode active material layer 11 (S2). Then, after the negative electrode active material layer 11 and the solid electrolyte layer 12 are pressed (S3), the positive electrode active material layer 13 is coated on the solid electrolyte layer 12 (S4). The base on which the positive electrode active material layer 13 is continuously formed is wound around the supply roller 31, and the positive electrode active material layer 13 is continuously transferred onto the solid electrolyte layer 12.

  Thereafter, through the densification pressing step (S5), in order to make the positive electrode active material layer 13 smaller than the solid electrolyte layer 12, a part of the positive electrode active material layer 13 is removed (trimmed) by a laser (S6) ). 5 and 6 are manufacturing process diagrams for explaining in detail the positive electrode removing step (S6) of the comparative example. As shown in FIG. 5, in the battery laminate P, the peripheral portion of the stacked positive electrode active material layer 13 is shaped like a frame so that the positive electrode active material layer 13 is smaller than the periphery of the solid electrolyte layer 12. The groove 15 is formed by removing the positive electrode active material layer 13 by laser.

  Then, the battery laminate P is cut out by laser scanning along the cutting line L so that the solid electrolyte layer 12 and the negative electrode active material layer 11 become larger than the positive electrode active material layer 13 along the groove 15 ( S7). In the battery laminate P manufactured in this manner, the sizes of the negative electrode active material layer 11, the solid electrolyte layer 12, and the positive electrode active material layer 13 are smaller than those of when applied. As shown in FIG. 6, the unnecessary portion D after the battery laminate P is cut out includes a part of the negative electrode active material layer 11, the solid electrolyte layer 12, and the positive electrode active material layer 13. Since the unnecessary portion D is discarded, the yield of the material is deteriorated. In particular, since the active material is expensive, it causes an increase in product cost when mass-produced.

  Further, in the comparative example, fumes are vaporized and scattered because trimming and cutting are performed using a laser. If foreign matter of a predetermined size (for example, 50 μm or more) adheres to the battery, a short circuit may occur.

  Furthermore, in order to obtain good performance as an all solid state battery, the solid electrolyte layer 12 needs to be formed thin (for example, 30 μm). However, when the solid electrolyte layer 12 is thin, there is a risk that the solid electrolyte layer 12 may be removed when trimming the positive electrode active material layer 13 with a laser. When the solid electrolyte layer 12 is removed, the negative electrode active material layer 11 is exposed, which causes a short circuit when the battery stack P is stacked. Therefore, when trimming the positive electrode active material layer 13 with a laser, the solid electrolyte layer 12 can not be thinned. In addition, when the solid electrolyte layer 12 is thickened, the entire thickness of the laminated all-solid-state battery manufactured by stacking a plurality of sheets becomes thick, which causes a problem that energy efficiency per volume of the battery is deteriorated.

  On the other hand, in the first embodiment, both the negative electrode active material layer 11 and the solid electrolyte layer 12 are intermittently applied to a predetermined size. In addition, the positive electrode active material layer 13 is smaller than the solid electrolyte layer 12 and intermittent coating is performed so as not to protrude from the periphery of the solid electrolyte layer 12. Thereby, a short circuit of the battery can be prevented, and a laser trimming process of removing the positive electrode active material layer 13 by a laser becomes unnecessary. Moreover, the negative electrode foil 10 is cut | disconnected in an uncoated part, and tab T is formed using the uncoated part contained in the laminated sheet W. As shown in FIG. As a result, there is no need to discard the positive electrode active material, the negative electrode active material, and the electrolyte, and the material yield can be improved.

Embodiment 2
FIG. 3 is a manufacturing process diagram illustrating the method of manufacturing a battery according to the second embodiment. In FIG. 3, the flow of each process is shown in the upper part, and the state of the battery laminate during each process is shown in the lower part. The second embodiment differs from the first embodiment in that the negative electrode active material layer 11 and the solid electrolyte layer 12 are continuously coated.

  In the second embodiment, the battery laminate P is disposed laterally on the negative electrode foil 10. That is, the longitudinal direction of the battery laminate P is formed along the width direction of the strip-like negative electrode foil 10, and the short direction of the battery laminate P is formed along the length direction of the strip-like negative electrode foil 10 There is. At one end side of the negative electrode foil 10, an uncoated portion extending in the length direction is formed. At this uncoated portion, a tab for current extraction is formed.

The negative electrode active material layer 11 is continuously coated on the negative electrode foil 10 (S31). Also, the solid electrolyte layer 12 is continuously formed on the continuously formed negative electrode active material layer 11 (S32).
Then, after the negative electrode active material layer 11 and the solid electrolyte layer 12 are pressed (S33), the positive electrode active material layer 13 is coated on the solid electrolyte layer 12 (S34). As in the first embodiment, the positive electrode active material layer 13 is intermittently smaller than the solid electrolyte layer 12 so as not to protrude from the periphery of the solid electrolyte layer 12. Thereafter, through the densification pressing step (S35), the battery laminate P having the tab T formed using the uncoated portion is cut out (S17).

  As described above, also in the second embodiment, the short circuit of the battery can be prevented, and the laser trimming process of removing the positive electrode active material layer 13 by the laser becomes unnecessary. As a result, it is not necessary to discard the positive electrode active material, and the material yield can be improved.

  The present invention is not limited to the above embodiment, and can be appropriately modified without departing from the scope of the present invention.

DESCRIPTION OF SYMBOLS 10 Negative electrode foil 11 Negative electrode active material layer 12 Solid electrolyte layer 13 Positive electrode active material layer 14 Positive electrode foil 15 Groove 20 1st press mechanism 30 Transfer mechanism 31 Supply roller 32 Transfer roller 33 Winding roller 40 2nd press mechanism F Multilayer whole solid Battery P Battery laminate W laminate sheet T tab L cutting line D unnecessary part

Claims (1)

The first active material layer is intermittently coated on the current collector, and the coated portion on which the first active material layer is coated, and the uncoated portion on which the first active material layer is not coated Forming a work portion;
Applying an electrolyte layer on the coating unit;
Applying a second active material layer on the electrolyte layer inside the end of the electrolyte layer;
Cutting the current collector at the uncoated portion;
Forming a tab for current extraction using the uncoated portion;
A method of manufacturing a battery, comprising:

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