Method for manufacturing battery

Abstract

To provide a novel method for manufacturing a battery that improves the efficiency of electrolyte pouring operations.SOLUTION: A method for manufacturing a battery includes: a step of arranging an electrode body 12 and a plate 13 with grooves formed on its surface in the interior space of an outer body 11; and a step of supplying electrolyte 14 to the outer body 11 so that at least part of the electrode body 12 and plate 13 are immersed in the electrolyte 141.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a method for manufacturing a battery. [Background technology]

[0002] In the manufacturing process of a battery that uses a liquid electrolyte (electrolytic solution), a liquid injection process is carried out in which the electrolyte is permeated into electrodes that contain an electrode active material. In order to increase the energy density of battery electrodes, they are sometimes subjected to a high-pressure pressing process. When the packing density of the electrode active material in the electrode is increased by pressing the electrode, the permeability of the electrolyte decreases. The decrease in the permeability of the electrolyte decreases the efficiency of the electrolyte injection process.

[0003] As a measure for increasing the permeability of the electrolyte during injection, Patent Document 1 proposes using grooves provided on the surface of the electrodes or separator as paths for the electrolyte. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2002-15773 A Summary of the Invention [Problem to be solved by the invention]

[0005] The method described in Patent Document 1 requires a step of providing grooves on the surface of the electrode or separator, which may reduce the efficiency of the entire battery manufacturing process. In addition, providing grooves in the electrode may reduce the energy density of the battery. One embodiment of the present disclosure aims to provide a novel method for manufacturing a battery that improves the efficiency of the electrolyte injection process. [Means for solving the problem]

[0006] Means for solving the above problems include the following embodiments. <1> A step of disposing an electrode body and a plate having a groove formed on a surface thereof in an internal space of an exterior body; and supplying an electrolyte to the exterior body so that the electrode body and at least a portion of the plates are immersed in the electrolyte. <2> The direction of the grooves of the plate is perpendicular to the liquid surface. <1> A method for manufacturing the battery according to claim 1. <3> The surface of the plate on which the groove is formed is in contact with the end surface of the electrode body. <1> or <2> A method for manufacturing the battery according to claim 1. <4> moving at least a portion of the electrolyte along the grooves of the plate to an area above a liquid level; <1> ~ <3> 13. A method for producing the battery according to claim 12. <5> reducing the pressure in the internal space of the exterior body; <1> ~ <4> 13. A method for producing the battery according to claim 12. Effect of the Invention

[0007] According to one embodiment of the present disclosure, a novel battery manufacturing method is provided that improves the efficiency of the electrolyte injection operation. [Brief description of the drawings]

[0008] [Figure 1] 1A to 1C are diagrams illustrating an example of a method for manufacturing a battery. [Diagram 2] FIG. 1 is a diagram illustrating an example of application of a battery module to an electric vehicle. [Diagram 3] FIG. 2 is a diagram illustrating an example of a configuration of a battery module. [Figure 4] FIG. 2 is a diagram illustrating an example of a configuration of a battery module. [Diagram 5] 2 is a diagram illustrating an example of a configuration of a battery cell included in a battery module. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] In the present disclosure, a numerical range indicated using "~" means a range that includes the numerical values ​​before and after "~" as the minimum and maximum values, respectively. In the numerical ranges described in the present disclosure, the upper or lower limit value described in a certain numerical range may be replaced with the upper or lower limit value of another numerical range described in the present disclosure. In the numerical ranges described in the present disclosure, the upper or lower limit value described in a certain numerical range may be replaced with a value shown in the examples. In the present disclosure, the term "process" refers not only to an independent process, but also to a process that cannot be clearly distinguished from other processes, as long as the intended purpose of the process is achieved. When an embodiment of the present disclosure is described with reference to the drawings, the configuration of the embodiment is not limited to the configuration shown in the drawings. In addition, the size of the members in each drawing is conceptual, and the relative relationship between the sizes of the members is not limited to this.

[0010] The method for manufacturing a battery according to the present disclosure includes: A step of disposing an electrode body and a plate having a groove formed on a surface thereof in an internal space of an exterior body; and supplying an electrolyte to the exterior body so that at least a portion of the electrode body and the plates are immersed in the electrolyte.

[0011] When the electrolyte solution is supplied to the internal space of the exterior body, the portion of the supplied electrolyte solution that is not absorbed by the electrode body immediately after supply remains in the internal space of the exterior body. The waiting time until the electrolyte solution remaining in the internal space of the exterior body is absorbed by the electrode body can be a factor in reducing the work efficiency. In particular, when the electrolyte solution is supplied in multiple batches, a long waiting time is likely to reduce the work efficiency.

[0012] In contrast, in the method disclosed herein, a plate having grooves on its surface is placed in the internal space of the exterior body together with the electrode assembly. The grooves of the plate induce capillary action in the electrolyte, causing at least a portion of the electrolyte to move above the liquid surface. As a result, the electrode assembly and the electrolyte come into contact with each other more frequently, and the waiting time until the electrolyte is absorbed into the electrode assembly is shortened. Furthermore, the method of the present disclosure can be carried out without processing the electrode body, and is therefore highly versatile.

[0013] Hereinafter, the process of placing the electrode body and a plate having a groove formed on its surface in the internal space of the outer casing is also referred to as "process 1," and the process of supplying an electrolyte to the outer casing so that at least a portion of the electrode body and the plate are immersed in the electrolyte is also referred to as "process 2."

[0014] (Process 1) In step 1, an electrode body and a plate having a groove formed on its surface are placed in the internal space of an exterior body. The type of exterior body is not particularly limited, and known exterior bodies such as a bag-shaped structure obtained by bonding the periphery of a flexible sheet, a metal can, etc. can be used. The electrode assembly includes a laminate including a positive electrode, a separator, and a negative electrode. The electrode assembly may be in the form of a laminate in which a plurality of laminate sheets cut to a predetermined size are stacked, or in which a long laminate is wound. The electrode body is preferably disposed in the internal space of the exterior body so that the end face of the electrode body (the part where the cross section of the electrode is exposed and which serves as the entrance of the main permeation path of the electrolyte) is located on the side of the electrode body.

[0015] As the plate, any plate having grooves formed on the surface thereof that can induce the movement of the electrolyte by capillary action can be used without any particular limitation. From the viewpoint of allowing the electrolyte to be efficiently absorbed into the electrode assembly, it is preferable that the plate is placed in the internal space of the exterior body with the surface on which the groove is formed in contact with the end face of the electrode assembly. The direction of the grooves of the plate disposed in the internal space of the exterior body is preferably perpendicular to the liquid surface. The number of plates disposed in the internal space of the exterior body may be one or two or more.

[0016] The dimensions of the plate are not particularly limited as long as it can be placed in the internal space of the exterior body together with the electrode assembly. From the viewpoint of the electrolyte migration promoting effect and ease of removal from the exterior body, it is preferable that the dimension L1 in the long side direction of the plate and the dimension L2 in the gravity direction of the electrode assembly when placed in the internal space of the exterior body satisfy the condition L1 ≧ L2.

[0017] (Process 2) In step 2, an electrolyte is supplied to the exterior body so that at least a portion of the electrode body and the plates are immersed in the electrolyte. The method for supplying the electrolyte to the exterior body is not particularly limited, and can be carried out by a known method. The electrolyte may be supplied once or multiple times.

[0018] In step 2, the electrolyte supplied to the exterior body is not absorbed into the electrode body immediately after supply, and remains in the internal space of the exterior body. Therefore, the electrolyte remaining in the internal space of the exterior body is kept waiting until it is absorbed into the electrode body. During this time, at least a part of the electrolyte moves to a region above the liquid level along the grooves of the plate.

[0019] The method of the present disclosure may include reducing the pressure in the interior space of the exterior body, which tends to promote the movement of the electrolyte along the grooves of the plate and promote absorption of the electrolyte into the electrode body.

[0020] After the designed amount of electrolyte has permeated into the electrode assembly, the plate is removed from the exterior body and the opening of the exterior body is closed. There are no particular limitations on the method for closing the opening of the exterior body, and the method can be a known method.

[0021] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. FIG. 1 is a diagram illustrating an example of a method for producing a battery. As shown in FIG. 1, an electrode body 12 and a plate 13 having a groove formed on the surface are arranged in the internal space of an exterior body 11. The electrode body 12 has an end surface on its side, and the plate 13 is disposed so as to be in contact with the end surface of the electrode body 12. The plate 13 has a groove (not shown) formed in a direction perpendicular to the liquid surface on the surface in contact with the end surface of the electrode body 12. Of the supplied electrolyte solution 14, the portion that is not absorbed by the electrode assembly 12 immediately after supply remains in the internal space of the exterior body 11. The electrode assembly 12 and the plate 13 are each partially immersed in the electrolyte solution 14. At least a portion of the electrolyte 14 remaining in the internal space of the exterior body 11 moves above the liquid surface along the grooves of the plate 13 due to capillary action. The electrolyte 14 that has moved along the grooves of the plate 13 comes into contact with the end face of the electrode body 12 in a region above the liquid surface of the electrolyte 14, and is absorbed into the electrode body 12. Once the electrolyte 14 has been sufficiently absorbed into the electrode body 12, the process of supplying the electrolyte 14 to the internal space of the exterior body 11 is repeated as necessary. Once the designed amount of electrolyte 14 has been supplied to exterior body 11, the opening of exterior body 11 is sealed.

[0022] In one embodiment, the material constituting the exterior body 11 may be a laminate (so-called laminate film) having a metal layer containing a metal such as aluminum and a heat seal layer containing a resin that melts when heated. In other words, the battery 10 may be a battery (so-called laminate battery) equipped with the exterior body 11 obtained by joining the periphery of a laminate film. Exterior body 11 may be made up of one member, or two or more members.

[0023] (battery) The type of battery produced by the method of the present disclosure is not particularly limited. Specific examples of batteries include secondary batteries such as lithium-ion secondary batteries, lead-acid batteries, nickel-metal hydride batteries, nickel-cadmium batteries, nickel-iron batteries, nickel-zinc batteries, silver oxide-zinc batteries, and cobalt-titanium lithium secondary batteries. From the standpoint of energy density, versatility, and the like, the battery may be a lithium ion secondary battery.

[0024] A lithium ion secondary battery includes, for example, a positive electrode, a negative electrode, a separator disposed between the positive electrode and the negative electrode, and an electrolyte.

[0025] The positive electrode includes, for example, a current collector and a positive electrode layer disposed on the current collector. The positive electrode layer includes a positive electrode material. The positive electrode active material may be a composite oxide of lithium and a transition metal (hereinafter, also referred to as a lithium transition metal composite oxide). Examples of the transition metal include Ni, Co, Mn, Al, B, Mg, Ti, V, Cr, Fe, Cu, Zn, Ga, Sr, Zr, Nb, In, Sn, Ta, W, etc. Examples of the lithium transition metal composite oxide include layered lithium transition metal composite oxides, spinel type lithium transition metal composite oxides, and olivine type lithium transition metal composite oxides. The layered lithium transition metal composite oxide includes those containing at least one transition metal selected from Ni, Co, and Mn. Specifically, LiNi a Co b Mn c Examples of such compounds include compounds represented by the structural formula O2 (where a, b, and c are each a number between 0 and 1, and a+b+c=1), and compounds in which one or more elements selected from Al, Mg, La, Ti, Zn, B, W, Fe, Cr, V, Ru, Cu, Cd, Ag, Y, Sc, Ga, In, As, Sb, Pt, Au, Si, etc. are added to the above compounds. A specific example of the spinel-type lithium transition metal composite oxide is LiMn2O4. A specific example of the olivine-type lithium transition metal composite oxide is LiMPO4 (M: Fe, Co, Ni, or Mn). The positive electrode active material contained in the positive electrode material may be one type alone or two or more types. The positive electrode layer may contain components such as a conductive assistant and a binder in addition to the positive electrode active material. Examples of materials constituting the current collector of the positive electrode include aluminum, aluminum alloys, nickel, titanium, stainless steel, etc. Examples of the shape of the current collector include foil, mesh, etc.

[0026] The negative electrode includes, for example, a current collector and a negative electrode layer that is disposed on the current collector and contains a negative electrode active material. Examples of the negative electrode active material include carbon materials such as graphite, hard carbon, soft carbon, and activated carbon, silicon, metallic lithium, lithium alloys, and lithium titanate (LTO). The negative electrode layer may contain components such as a conductive assistant and a binder in addition to the negative electrode active material. Examples of the material constituting the negative electrode current collector include copper, copper alloy, nickel, titanium, stainless steel, etc. Examples of the shape of the negative electrode current collector include foil, mesh, etc.

[0027] Examples of the separator include nonwoven fabrics, cloths, microporous films, etc., whose main component is a polyolefin such as polyethylene or polypropylene. When the lithium ion secondary battery uses a solid electrolyte, it is not necessary to use a separator.

[0028] As the electrolyte, a solution in which a known lithium salt such as LiPF6 is dissolved in an organic solvent can be used without any particular limitation.

[0029] The battery of the present disclosure may be installed in an electric vehicle. An example in which the battery of the present disclosure is applied to an electric vehicle will be described below with reference to the drawings. In the following description, "battery cell 20" corresponds to the battery of the present disclosure.

[0030] Fig. 2 is a schematic plan view showing a main part of a vehicle 100 to which a battery pack 10 according to an embodiment is applied. As shown in Fig. 2, the vehicle 100 is an electric vehicle (BEV: Battery Electric Vehicle) in which the battery pack 10 is mounted under the floor. Note that the arrows UP, FR, and LH in each figure indicate the upper side in the vehicle vertical direction, the front side in the vehicle front-rear direction, and the left side in the vehicle width direction, respectively. When describing using the front-rear, left-right, up-down directions, they refer to the front-rear in the vehicle front-rear direction, the left-right in the vehicle width direction, and the up-down in the vehicle vertical direction, unless otherwise specified.

[0031] As an example, in the vehicle 100 of this embodiment, a DC / DC converter 102, an electric compressor 104, and a PTC (Positive Temperature Coefficient) heater 106 are disposed on the vehicle front side of the battery pack 10. In addition, a motor 108, a gear box 110, an inverter 112, and a charger 114 are disposed on the vehicle rear side of the battery pack 10.

[0032] The direct current output from the battery pack 10 has its voltage adjusted by a DC / DC converter 102, and is then supplied to an electric compressor 104, a PTC heater 106, an inverter 112, etc. In addition, power is supplied to a motor 108 via the inverter 112, causing the rear wheels to rotate and causing the vehicle 100 to run.

[0033] A charging port 116 is provided on the right side at the rear of the vehicle 100, and by connecting a charging plug of an external charging device (not shown) to the charging port 116, power can be stored in the battery pack 10 via the on-board charger 114.

[0034] The arrangement and structure of each component constituting the vehicle 100 are not limited to the above-mentioned configuration. For example, the present invention may be applied to a hybrid vehicle (HV: Hybrid Vehicle) equipped with an engine or a plug-in hybrid vehicle (PHEV: Plug-in Hybrid Electric Vehicle). In addition, in the present embodiment, the vehicle is a rear-wheel drive vehicle in which the motor 108 is mounted at the rear of the vehicle, but the present invention is not limited to this. The vehicle may be a front-wheel drive vehicle in which the motor 108 is mounted at the front of the vehicle, or a pair of motors 108 may be mounted at the front and rear of the vehicle. Furthermore, the vehicle may be equipped with an in-wheel motor on each wheel.

[0035] The battery pack 10 includes a plurality of battery modules 11. In the present embodiment, as an example, ten battery modules 11 are provided. Specifically, five battery modules 11 are arranged on the right side of the vehicle 100 in the vehicle longitudinal direction, and five battery modules 11 are arranged on the left side of the vehicle 100 in the vehicle longitudinal direction. In addition, the respective battery modules 11 are electrically connected to each other.

[0036] Fig. 3 is a schematic perspective view of the battery module 11. As shown in Fig. 3, the battery module 11 is formed in a substantially rectangular parallelepiped shape with the vehicle width direction as the longitudinal direction. The outer shell of the battery module 11 is formed of an aluminum alloy. For example, the outer shell of the battery module 11 is formed by joining aluminum die castings to both ends of an aluminum alloy extrusion material by laser welding or the like.

[0037] A pair of voltage terminals 12 and a connector 14 are provided at both ends of the battery module 11 in the vehicle width direction. A flexible printed circuit board 21, which will be described later, is connected to the connector 14. In addition, bus bars (not shown) are welded to both ends of the battery module 11 in the vehicle width direction.

[0038] The length MW of the battery module 11 in the vehicle width direction is, for example, 350 mm to 600 mm, the length ML in the vehicle front-rear direction is, for example, 150 mm to 250 mm, and the height MH in the vehicle up-down direction is, for example, 80 mm to 110 mm.

[0039] Fig. 4 is a plan view of the battery module 11 with the top cover removed. As shown in Fig. 4, a plurality of battery cells 20 are housed in an arranged state inside the battery module 11. In this embodiment, as an example, 24 battery cells 20 are arranged in the front-rear direction of the vehicle and bonded to one another.

[0040] A flexible printed circuit (FPC) 21 is disposed on the battery cells 20. The flexible printed circuit 21 is formed in a strip shape with the vehicle width direction as the longitudinal direction, and a thermistor 23 is provided on each of both ends of the flexible printed circuit 21. The thermistor 23 is not bonded to the battery cells 20, and is configured to be pressed towards the battery cells 20 by the upper lid of the battery module 11.

[0041] One or more cushioning materials (not shown) are housed inside the battery module 11. For example, the cushioning materials are elastically deformable thin plate-like members, and are arranged between adjacent battery cells 20 with the arrangement direction of the battery cells 20 being the thickness direction. As an example in this embodiment, cushioning materials are arranged at both ends of the battery module 11 in the longitudinal direction and in the central portion in the longitudinal direction.

[0042] Fig. 5 is a schematic diagram of a battery cell 20 housed in a battery module 11, viewed from the thickness direction. As shown in Fig. 5, the battery cell 20 is formed in a substantially rectangular plate shape, and houses an electrode body (not shown) inside. The electrode body is configured by laminating a positive electrode, a negative electrode, and a separator, and is sealed with a laminate film 22.

[0043] In this embodiment, as an example, the housing portion for the electrode body is formed by folding and pasting an embossed sheet-like laminate film 22. Note that, although both a single cup embossed structure in which embossing is performed at one place and a double cup embossed structure in which embossing is performed at two places can be adopted, the present embodiment adopts a single cup embossed structure with a drawing depth of about 8 mm to 10 mm.

[0044] The upper ends of the battery cells 20 at both ends in the longitudinal direction are bent to form corners. The upper end of the battery cells 20 is also bent, and a fixing tape 24 is wrapped around the upper end of the battery cells 20 along the longitudinal direction.

[0045] Here, terminals (tabs) 26 are provided at both longitudinal ends of the battery cell 20. In this embodiment, as an example, the terminals 26 are provided at positions offset downward from the vertical center of the battery cell 20. The terminals 26 are joined to a bus bar (not shown) by laser welding or the like.

[0046] The length CW1 of the battery cell 20 in the vehicle width direction is, for example, 530 mm to 600 mm, 600 mm to 700 mm, 700 mm to 800 mm, 800 to 900 mm, 1000 mm or more, the length CW2 of the region in which the electrode body is housed is, for example, 500 mm to 520 mm, 600 mm to 700 mm, 700 mm to 800 mm, 800 to 900 mm, 1000 mm or more, and the height CH of the battery cell 20 is, for example, 80 mm to 110 mm, 110 mm to 140 mm. The thickness of the battery cell 20 is 5.0 mm to 7.0 mm, 7.0 mm to 9.0 mm, 9.0 mm to 11.0 mm, and the height TH of the terminal 26 is 40 mm to 50 mm, 50 mm to 60 mm, 60 mm to 70 mm. [Explanation of symbols]

[0047] 11: Exterior body 12: Electrode body 13: Plate 14: Electrolyte

Claims

1. A step of disposing an electrode body and a plate having a groove formed on a surface thereof in an internal space of an exterior body; and supplying an electrolyte to the exterior body so that the electrode body and at least a portion of the plates are immersed in the electrolyte.

2. The method for manufacturing a battery according to claim 1 , wherein the grooves in the plate are oriented perpendicular to the liquid surface.

3. The method for manufacturing a battery according to claim 1 or 2, wherein the surface of the plate on which the groove is formed is in contact with the end surface of the electrode assembly.

4. 3. The method of claim 1, further comprising: moving at least a portion of the electrolyte along the grooves of the plate to a region above the liquid level.

5. The method for producing a battery according to claim 1 or 2, further comprising reducing the pressure in an internal space of the exterior body.

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