Method and device for manufacturing battery

Abstract

To provide a novel method and device for manufacturing a battery that improve the efficiency of electrolyte pouring operations.SOLUTION: A method for manufacturing a battery includes: a first step of supplying the electrolyte to the interior space of an outer body in which an electrode body is housed; and a second step of supplying the electrolyte extracted from the interior space of the outer body to the interior space of the outer body. The second step includes removing air bubbles contained in the electrolyte extracted from the interior space of the outer body.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] In the manufacturing process of a battery that uses an electrolytic solution obtained by dissolving an electrolyte in an organic solvent, a liquid injection operation is carried out in which the electrolytic solution is supplied to the inside of an exterior body that houses an electrode assembly and the electrolytic solution is allowed to permeate the electrode assembly. 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 reduces the efficiency of the electrolyte injection process.

[0003] As a measure to improve the permeability of the electrolyte during the injection operation, Patent Document 1 proposes flowing the electrolyte at a constant flow rate by continuously supplying and discharging the electrolyte to an exterior body that houses an electrode body. According to this method, the electrolyte causes turbulence while colliding with the electrode body, which is said to improve the permeation speed of the electrolyte into the electrode body. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2015-5331 A Summary of the Invention [Problem to be solved by the invention]

[0005] In the method described in Patent Document 1, the electrolyte in a fluid state may contain air bubbles generated by contact with the electrode body, and in this case, the air bubbles contained in the electrolyte may hinder the electrolyte from penetrating into the electrode body. One embodiment of the present disclosure aims to provide a novel battery manufacturing method and battery manufacturing apparatus that improve the efficiency of the electrolyte injection operation. [Means for solving the problem]

[0006] Means for solving the above problems include the following embodiments. <1> A first step of supplying an electrolyte solution into an internal space of an exterior body in which an electrode body is housed; A second step of supplying the electrolyte solution removed from the internal space of the exterior body to the internal space of the exterior body, A second step of the method for manufacturing a battery includes removing air bubbles contained in the electrolyte solution removed from the internal space of the exterior body. <2> The second step includes circulating the electrolyte. <1> A method for manufacturing the battery according to claim 1. <3> The air bubbles are removed using a vacuum degassing device. <1> or <2> A method for manufacturing the battery according to claim 1. <4> The amount of the electrolyte in the internal space of the exterior body is an amount in which more than half of the electrode body is immersed. <1> ~ <3> 13. A method for producing the battery according to claim 12. <5> A first supply unit that supplies an electrolyte to an internal space of the exterior body in which the electrode body is housed; a second supply unit that supplies the electrolyte solution removed from the internal space of the exterior body to the internal space of the exterior body; The second supply unit includes a degassing unit that removes air bubbles contained in the electrolyte solution removed from the internal space of the exterior body. Effect of the Invention

[0007] According to one embodiment of the present disclosure, there is provided a novel battery manufacturing method and battery manufacturing apparatus that improve 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] <Battery manufacturing method> The method for manufacturing a battery according to the present disclosure includes: A first step of supplying an electrolyte solution into an internal space of an exterior body in which an electrode body is housed; A second step of supplying the electrolyte solution removed from the internal space of the exterior body to the internal space of the exterior body, The second step includes removing air bubbles contained in the electrolyte solution removed from the internal space of the exterior body.

[0011] When the electrolyte is supplied to the internal space of the exterior body, the portion of the electrolyte that is not absorbed into the electrode body immediately after supply remains in the internal space of the exterior body. In the conventional method, the work is stopped and the work is waited until the electrolyte that remains in the internal space of the exterior body is absorbed into the electrode body by capillary action or the like. This waiting time can be a factor in reducing work efficiency. In particular, when the electrolyte is supplied in multiple batches, the work efficiency is likely to decrease if the above-mentioned waiting time is long.

[0012] In contrast, the method disclosed herein includes a first step of supplying an electrolyte to the internal space of the exterior body, as well as a second step of supplying the electrolyte removed from the internal space of the exterior body to the internal space of the exterior body. By carrying out the second step, the electrolyte solution in the internal space of the exterior body can be caused to flow. When the electrolyte solution in the exterior body is in a flowing state, the rate of permeation into the electrode body is increased compared to when the electrolyte solution is in a stationary (stagnant) state.

[0013] Furthermore, the method of the present disclosure includes removing air bubbles contained in the electrolyte solution removed from the internal space of the exterior body in the second step. The electrolyte solution supplied to the internal space of the exterior body in the first step may contain air bubbles generated by contact with the electrode assembly disposed within the exterior body. Air bubbles contained in the electrolyte solution may be a factor preventing the electrolyte solution from penetrating into the electrode assembly. In the method of the present disclosure, air bubbles contained in the electrolyte solution removed from the exterior body are removed before the electrolyte solution is supplied back to the exterior body, thereby maintaining good permeability of the electrolyte solution into the electrode assembly.

[0014] (1st step) In the first step, an electrolyte is supplied to the internal space of the exterior body in which the electrode assembly is housed. The supply of the electrolytic solution in the first step is carried out, for example, by using a first pipe that connects a tank that stores the electrolytic solution and a first supply port provided in the exterior body.

[0015] The amount of electrolyte supplied to the internal space of the exterior body in the first step may be the same as the designed amount of electrolyte contained in the battery produced by the method of the present disclosure, or it may be less than the designed amount, or it may be more than the designed amount. When the amount of the electrolytic solution supplied is less than the designed amount of the electrolytic solution, for example, the supply of the electrolytic solution in the first step is carried out multiple times. When the supply amount of the electrolyte is more than the designed amount of the electrolyte, for example, the excess electrolyte is removed from the electrolyte removed from the exterior body in the second step. The removed electrolyte may be reused in the manufacture of the battery. In the method of the present disclosure, since the electrolyte solution is extracted from the exterior body in the second step, it is possible to increase the amount of electrolyte solution supplied to the internal space of the exterior body in the first step from the designed amount, thereby increasing the contact area between the electrolyte solution and the electrode body, and enabling the electrolyte solution to efficiently permeate the electrode body.

[0016] Of the electrolyte solution supplied in the first step, the portion that is not absorbed by the electrode assembly remains in the internal space of the exterior body. From the viewpoint of efficient penetration of the electrolyte solution into the electrode assembly, it is preferable that the amount of electrolyte solution remaining in the internal space of the exterior body is an amount that immerses at least half of the electrode assembly.

[0017] (2nd process) In the second step, the electrolyte solution removed from the internal space of the exterior body is supplied to the internal space of the exterior body. The supply of the electrolytic solution in the second step is carried out, for example, by using a second pipe that connects an electrolytic solution outlet provided in the exterior body and a second electrolytic solution supply port provided in the exterior body.

[0018] The second step may include circulating the electrolyte, i.e., the step of supplying the electrolyte taken out of the interior space of the exterior body to the interior space of the exterior body may be continuously repeated.

[0019] The second step includes removing air bubbles contained in the electrolyte solution removed from the internal space of the exterior body. The method for removing bubbles from the electrolytic solution is not particularly limited, and can be carried out using a known degassing device, such as a vacuum degassing device, a centrifugal degassing device, or an ultrasonic degassing device, among which a vacuum degassing device is preferred.

[0020] From the viewpoint of efficiently permeating the electrolyte solution into the electrode body, it is preferable that the outlet for removing the electrolyte solution from the outer casing be provided lower in the direction of gravity than the second supply port for supplying the electrolyte solution to the outer casing. From the viewpoint of efficiently permeating the electrolyte into the electrode assembly, the second step is preferably carried out while reducing the pressure in the internal space of the exterior body. The second step may be carried out using a power source such as a pump.

[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. 1 has a first supply port 12, a second supply port 13, and a discharge port 14 for supplying or discharging an electrolyte. An electrode assembly 15 is disposed in the internal space of the exterior body 11. The first supply port 12 is connected by a first pipe 17 to a tank 16 that stores the electrolyte. The second supply port 13 is connected to one end of a second pipe 18 , and the discharge port 14 is connected to the other end of the second pipe 18 . A defoaming device 19 for removing air bubbles contained in the electrolytic solution is connected to the second pipe 18.

[0022] The electrolyte 20 supplied from the tank 16 through the first pipe 17 resides in the internal space of the exterior body 11. The electrolyte 20 contains air bubbles (not shown) generated by contact with the electrode body 12, etc.

[0023] The electrolytic solution 20 is taken out from the outlet 14 of the exterior body 11 , passes through the second pipe 18 , and is supplied again into the internal space of the exterior body 11 from the second supply port 13 of the exterior body 11 . Before the electrolyte solution 20 removed from the internal space of the exterior body 11 is supplied again to the internal space of the exterior body 11, air bubbles are removed by a defoaming device 19 provided in the second pipe.

[0024] Once the electrolyte solution 20 has been sufficiently absorbed into the electrode body 15, the first step of supplying the electrolyte solution 20 from the tank 16 to the internal space of the outer casing 11 and the second step of supplying the electrolyte solution removed from the outer casing 11 to the outer casing 11 are repeated as necessary. Once the designed amount of electrolyte 20 has been supplied to exterior body 11, first supply port 12, second supply port 13 and outlet port 14 are sealed.

[0025] 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 produced by the method of the present disclosure 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 of one member as shown in FIG. 1, or may be made of two or more members.

[0026] <Battery manufacturing equipment> The battery manufacturing apparatus of the present disclosure comprises: A first supply unit that supplies an electrolyte to an internal space of the exterior body in which the electrode body is housed; a second supply unit that supplies the electrolyte solution removed from the internal space of the exterior body to the internal space of the exterior body; The second supply unit includes a defoaming unit that removes air bubbles contained in the electrolyte solution taken out from the internal space of the exterior body.

[0027] The configuration of the first supply unit in the device of the present disclosure is not particularly limited as long as it is capable of supplying the electrolyte to the internal space of the exterior body that houses the electrode assembly. The first supply unit may include, for example, a first pipe that connects a tank that stores the electrolytic solution and a first supply port provided in the exterior body.

[0028] The configuration of the second supply unit in the device of the present disclosure is not particularly limited as long as it is a configuration capable of supplying the electrolyte solution removed from the internal space of the exterior body to the internal space of the exterior body. The second supply unit may include, for example, a second pipe that connects an outlet for removing the electrolytic solution from the exterior body and a second supply port for re-supplying the electrolytic solution to the exterior body. The configuration of the degassing section included in the second pipe is not particularly limited, and can be selected from known degassing devices.

[0029] For details and preferred embodiments of the method of using the device of the present disclosure, reference can be made to the contents described above in relation to the method of manufacturing a battery of the present disclosure.

[0030] (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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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 longitudinal 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 longitudinal direction, the left-right in the vehicle width direction, and the up-down in the vehicle vertical direction, unless otherwise specified.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] 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 wound around the upper end of the battery cells 20 along the longitudinal direction.

[0052] 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.

[0053] 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]

[0054] 11: Exterior body 12: 1st supply port 13:Second supply port 14: Outlet 15: Electrode body 16: Tank 17: First pipe 18: Second piping 19: Defoaming device 20: Electrolyte

Claims

1. A first step of supplying an electrolyte solution into an internal space of an exterior body in which an electrode body is housed; A second step of supplying the electrolyte solution removed from the internal space of the exterior body to the internal space of the exterior body, A second step of the method for manufacturing a battery includes removing air bubbles contained in the electrolyte solution removed from the internal space of the exterior body.

2. The method of claim 1 , wherein the second step comprises circulating the electrolyte.

3. The method for producing a battery according to claim 1 or 2, wherein the air bubbles are removed using a vacuum degassing device.

4. The method for manufacturing a battery according to claim 1 or 2, wherein an amount of the electrolyte in the internal space of the exterior body is an amount that immerses at least half of the electrode body.

5. A first supply unit that supplies an electrolyte to an internal space of the exterior body in which the electrode body is housed; a second supply unit that supplies the electrolyte solution taken out from the internal space of the exterior body to the internal space of the exterior body, The second supply unit includes a degassing unit that removes air bubbles contained in the electrolyte solution removed from the internal space of the exterior body.

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