Battery manufacturing method and battery manufacturing apparatus

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 method for manufacturing a battery and a battery manufacturing apparatus.

Background Art

[0002] In the manufacturing process of a battery using an electrolytic solution obtained by dissolving an electrolyte in an organic solvent, a liquid injection operation is performed in which the electrolytic solution is supplied into the exterior body that houses the electrode body and the electrolytic solution is allowed to penetrate into the electrode body. The electrodes of a battery may be subjected to a process of pressing at a high pressure in order to increase the energy density. When the filling density of the electrode active material in the electrode increases due to pressing the electrode, the permeability of the electrolytic solution decreases. The decrease in the permeability of the electrolytic solution is the cause of the decrease in the efficiency of the liquid injection operation.

[0003] As a measure to increase the permeability of the electrolytic solution during the liquid injection operation, Patent Document 1 proposes to cause a constant flow rate of the electrolytic solution to flow by continuously discharging the electrolytic solution while supplying it to the exterior body that houses the electrode body. According to this method, it is said that the electrolytic solution collides with the electrode body while causing a turbulent flow, and the penetration rate of the electrolytic solution into the electrode body is improved.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the method described in Patent Document 1, there is a possibility that the flowing electrolytic solution contains bubbles generated by contact with the electrode body. In this case, the bubbles contained in the electrolytic solution may prevent penetration into the electrode body. One embodiment of the present disclosure aims at a novel method for manufacturing a battery and a battery manufacturing apparatus in which the efficiency of the liquid injection operation of the electrolytic solution is improved. [Means for solving the problem]

[0006] The following embodiments are included as means for solving the above problems. <1> The first step involves supplying an electrolyte solution to the internal space of the outer casing that houses the electrode body, The second step includes supplying the electrolyte extracted from the internal space of the outer casing back into the internal space of the outer casing, A method for manufacturing a battery, comprising the second step of removing air bubbles contained in the electrolyte taken out from the internal space of the outer casing. <2> The second step includes circulating the electrolyte, <1> The battery manufacturing method described above. <3> The aforementioned bubbles are removed using a vacuum degassing device. <1> or <2> The battery manufacturing method described above. <4> The amount of electrolyte in the internal space of the outer casing is such that more than half of the electrode body is submerged. <1> ~ <3> A method for manufacturing a battery as described in any one of the items. <5> A first supply unit that supplies electrolyte to the internal space of the outer casing in which the electrode body is housed, It includes a second supply unit that supplies the electrolyte extracted from the internal space of the outer casing back into the internal space of the outer casing, The second supply unit is a battery manufacturing apparatus that includes a degassing unit for removing air bubbles contained in the electrolyte taken out from the internal space of the outer casing. [Effects of the Invention]

[0007] According to one embodiment of the present disclosure, a novel battery manufacturing method and battery manufacturing apparatus are provided in which the efficiency of the electrolyte injection work is improved. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic diagram illustrating one example of a battery manufacturing method. [Figure 2] This diagram schematically illustrates an example of the application of a battery module to an electric vehicle. [Figure 3] This diagram schematically shows an example of a battery module configuration. [Figure 4] This diagram schematically shows an example of a battery module configuration. [Figure 5] This diagram schematically shows an example of the configuration of a battery cell included in a battery module. [Modes for carrying out the invention]

[0009] In this disclosure, a numerical range indicated using "~" means a range that includes the numbers written before and after "~" as the minimum and maximum values, respectively. In the numerical ranges described in stages in this disclosure, the upper or lower limit stated in one numerical range may be replaced with the upper or lower limit of another numerical range described in stages. In the numerical ranges described in this disclosure, the upper or lower limit stated in one numerical range may be replaced with the values ​​shown in the examples. In this disclosure, the term "process" includes not only independent processes but also processes that cannot be clearly distinguished from other processes, as long as their intended purpose is achieved. When embodiments are described in this disclosure with reference to the drawings, the configuration of such embodiments is not limited to the configuration shown in the drawings. Furthermore, the sizes of the components in each figure are conceptual, and the relative relationships between the sizes of the components are not limited thereto.

[0010] <Battery manufacturing method> The battery manufacturing method disclosed herein is The first step involves supplying an electrolyte solution to the internal space of the outer casing that houses the electrode body, The second step includes supplying the electrolyte extracted from the internal space of the outer casing back into the internal space of the outer casing, The second step includes removing air bubbles contained in the electrolyte extracted from the internal space of the outer casing.

[0011] When the electrolytic solution is supplied to the internal space of the exterior body, among the supplied electrolytic solution, the portion that is not absorbed by the electrode body immediately after supply stays in the internal space of the exterior body. In the conventional method, the operation is stopped and waiting is performed until the electrolytic solution staying in the internal space of the exterior body is absorbed by the electrode body due to capillary action or the like. This waiting time can be a factor that reduces work efficiency. In particular, when the electrolytic solution is supplied in multiple portions, if the above waiting time is long, the work efficiency is likely to decrease.

[0012] In contrast, in the method of the present disclosure, in addition to the first step of supplying the electrolytic solution to the internal space of the exterior body, a second step of supplying the electrolytic solution taken out from the internal space of the exterior body back to the internal space of the exterior body is performed. By performing the second step, the electrolytic solution in the internal space of the exterior body can be made to flow. When the electrolytic solution in the exterior body is in a flowing state, the penetration rate into the electrode body is increased compared to the case where the electrolytic solution is stationary (staying).

[0013] Furthermore, the method of the present disclosure includes removing bubbles contained in the electrolytic solution taken out from the internal space of the exterior body in the second step. The electrolytic solution supplied to the internal space of the exterior body in the first step may contain bubbles generated by contact with the electrode body disposed in the exterior body. The bubbles contained in the electrolytic solution can be a factor that hinders the penetration of the electrolytic solution into the electrode body. In the method of the present disclosure, the bubbles contained in the electrolytic solution taken out from the exterior body are removed before the electrolytic solution is supplied back to the exterior body again. Thereby, the permeability of the electrolytic solution to the electrode body is maintained well.

[0014] (First step) In the first step, the electrolytic solution is supplied to the internal space of the exterior body in which the electrode body is accommodated. The supply of the electrolytic solution in the first step is carried out, for example, using a first pipe that connects a tank for storing the electrolytic solution and a first supply port provided on the exterior body.

[0015] The amount of electrolyte supplied to the internal space of the outer casing in the first step may be the same as the design amount of electrolyte contained in the battery manufactured by the method of this disclosure, may be less than the design amount, or may be more than the design amount. If the amount of electrolyte supplied is less than the design amount, for example, the electrolyte supply in the first process may be repeated multiple times. If the amount of electrolyte supplied exceeds the design amount, the excess is removed from the electrolyte extracted from the casing in the second step, for example. The removed electrolyte may be reused in the manufacture of the battery. In the method disclosed herein, since the electrolyte is removed from the outer casing in the second step, it is possible to supply more electrolyte to the internal space of the outer casing in the first step than the designed amount. This increases the contact area between the electrolyte and the electrode body, and enables efficient penetration of the electrolyte into the electrode body.

[0016] Of the electrolyte supplied in the first step, the portion not absorbed by the electrode remains in the internal space of the outer casing. From the viewpoint of efficiently penetrating the electrode with the electrolyte, it is preferable that the amount of electrolyte remaining in the internal space of the outer casing is enough to immerse more than half of the electrode.

[0017] (2nd process) In the second step, the electrolyte extracted from the internal space of the outer casing is supplied back into the internal space of the outer casing. In the second step, the electrolyte is supplied, for example, using a second pipe that connects an electrolyte outlet provided on the outer casing to a second electrolyte supply port provided on the outer casing.

[0018] The second step may include circulating the electrolyte. That is, the step of supplying the electrolyte taken from the internal space of the outer casing back into the internal space of the outer casing may be repeated continuously.

[0019] The second step includes removing air bubbles contained in the electrolyte extracted from the internal space of the outer casing. The method for removing air bubbles from the electrolyte is not particularly limited and can be carried out using known defoaming devices. Examples of defoaming devices include vacuum defoaming devices, centrifugal defoaming devices, ultrasonic defoaming devices, etc., with vacuum defoaming devices being preferred.

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

[0021] The embodiments of this disclosure will be described below with reference to the drawings. Figure 1 is a schematic diagram illustrating an example of a battery manufacturing method. The outer casing 11 shown in Figure 1 has a first supply port 12, a second supply port 13, and a discharge port 14 for supplying or discharging electrolyte. The electrode body 15 is arranged in the internal space of the outer casing 11. The first supply port 12 is connected to a tank 16 for storing electrolyte by a first pipe 17. The second supply port 13 is connected to one end of the 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 electrolyte is connected to the second pipe 18.

[0022] The electrolyte 20 supplied from the tank 16 via the first pipe 17 is contained within the internal space of the outer casing 11. The electrolyte 20 contains bubbles (not shown) generated by contact with the electrode body 12, etc.

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

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

[0025] In one embodiment, the material constituting the outer casing 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. That is, a battery manufactured by the method of this disclosure may be a battery (so-called laminate battery) having an outer casing 11 obtained by joining the periphery of a laminate film. The exterior body 11 may consist of one member or two or more members, as shown in Figure 1.

[0026] <Battery manufacturing equipment> The battery manufacturing apparatus of this disclosure is A first supply unit that supplies electrolyte to the internal space of the outer casing in which the electrode body is housed, It includes a second supply unit that supplies the electrolyte extracted from the internal space of the outer casing back into the internal space of the outer casing, The second supply unit includes a defoaming unit that removes air bubbles contained in the electrolyte taken out from the internal space of the outer casing.

[0027] The configuration of the first supply unit in the apparatus of this disclosure is not particularly limited as long as it is capable of supplying electrolyte to the internal space of the outer casing in which the electrode body is housed. The first supply unit may, for example, include a tank for storing electrolyte and a first supply port provided in the outer casing, and a first pipe connecting them.

[0028] The configuration of the second supply unit in the apparatus of this disclosure is not particularly limited as long as it is configured to supply the electrolyte extracted from the internal space of the outer casing back into the internal space of the outer casing. The second supply unit may, for example, include a second pipe connecting an outlet for extracting electrolyte from the outer casing and a second supply outlet for resupplying electrolyte to the outer casing. The configuration of the defoaming section included in the second piping is not particularly limited and can be selected from known defoaming devices.

[0029] Details of how to use the apparatus of this disclosure and preferred embodiments can be found in the description of the battery manufacturing method of this disclosure described above.

[0030] (battery) The types of batteries manufactured by the method of this disclosure are not particularly limited. Specific examples of batteries include lithium-ion 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 batteries. From the standpoint of energy density, versatility, etc., the battery may be a lithium-ion secondary battery.

[0031] A lithium-ion secondary battery comprises, for example, a positive electrode, a negative electrode, a separator placed between the positive and negative electrodes, and an electrolyte.

[0032] The positive electrode comprises, for example, a current collector and a positive electrode layer placed on the current collector. The positive electrode layer contains a positive electrode material. Examples of positive electrode active materials include lithium-transition metal composite oxides (hereinafter also referred to as lithium transition metal composite oxides). Examples of transition metals include Ni, Co, Mn, Al, B, Mg, Ti, V, Cr, Fe, Cu, Zn, Ga, Sr, Zr, Nb, In, Sn, Ta, and W. Examples of lithium transition metal composite oxides include layered lithium transition metal composite oxides, spinel-type lithium transition metal composite oxides, and olivine-type lithium transition metal composite oxides. Examples of layered lithium transition metal composite oxides include those containing at least one transition metal selected from Ni, Co, and Mn. Specifically, LiNi a Co b Mn c Examples include compounds represented by the structural formula of O2 (where a, b, and c are each numbers between 0 and 1, and a+b+c=1), and compounds obtained by adding 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. to the aforementioned compound. A specific example of a spinel-type lithium transition metal composite oxide is LiMn2O4. Specific examples of olivine-type lithium transition metal composite oxides include LiMPO4 (M: Fe, Co, Ni, or Mn). The positive electrode active material contained in the positive electrode material may be a single type or two or more types. The positive electrode layer may contain components such as conductive additives and binders in addition to the positive electrode active material. Materials that can be used to construct the positive electrode current collector include aluminum, aluminum alloy, nickel, titanium, and stainless steel. The shape of the current collector can include foil, mesh, etc.

[0033] The negative electrode comprises, for example, a current collector and a negative electrode layer disposed on the current collector and containing a negative electrode active material. Examples of negative electrode active materials include carbon materials such as graphite, hard carbon, soft carbon, and activated carbon, as well as silicon, metallic lithium, lithium alloys, and lithium titanate (LTO). The negative electrode layer may contain components such as conductive additives and binders in addition to the negative electrode active material. The materials used to construct the negative electrode current collector include copper, copper alloys, nickel, titanium, and stainless steel. The shape of the negative electrode current collector can be foil, mesh, etc.

[0034] Examples of separators include nonwoven fabrics, cloths, and microporous films mainly composed of polyolefins such as polyethylene and polypropylene. When a lithium-ion secondary battery uses a solid electrolyte, a separator may not be necessary.

[0035] As the electrolyte, any known lithium salt such as LiPF6 dissolved in an organic solvent can be used without any particular limitations.

[0036] The battery of this disclosure may be installed in an electric vehicle. An example of applying the battery of this disclosure 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 this disclosure.

[0037] Figure 2 is a schematic plan view showing the main parts of a vehicle 100 to which the battery pack 10 according to the embodiment is applied. As shown in Figure 2, the vehicle 100 is a battery electric vehicle (BEV) with the battery pack 10 mounted under the floor. In each figure, the arrows UP, FR, and LH indicate the upper side in the vertical direction of the vehicle, the front side in the longitudinal direction of the vehicle, and the left side in the width direction of the vehicle, respectively. When describing the directions of front, rear, left, right, up, and down, unless otherwise specified, they refer to the front and rear in the longitudinal direction of the vehicle, the left and right in the width direction of the vehicle, and the up and down in the vertical direction of the vehicle.

[0038] In this embodiment, the vehicle 100, as an example, has a DC / DC converter 102, an electric compressor 104, and a PTC (Positive Temperature Coefficient) heater 106 positioned in front of the battery pack 10. The motor 108, gearbox 110, inverter 112, and charger 114 are positioned behind the battery pack 10.

[0039] The DC current output from the battery pack 10 is voltage-adjusted by the DC / DC converter 102 and then supplied to the electric compressor 104, PTC heater 106, inverter 112, etc. Power is also supplied to the motor 108 via the inverter 112, causing the rear wheels to rotate and the vehicle 100 to move.

[0040] A charging port 116 is provided on the right side of the rear of the vehicle 100. By connecting a charging plug from an external charging device (not shown) to the charging port 116, power can be stored in the battery pack 10 via the onboard charger 114.

[0041] The arrangement and structure of the components constituting the vehicle 100 are not limited to the configuration described above. For example, it may be applied to a hybrid vehicle (HV) or a plug-in hybrid electric vehicle (PHEV) equipped with an engine. In this embodiment, the motor 108 is mounted at the rear of the vehicle and it is a rear-wheel drive vehicle, but it is not limited to this, and it may be a front-wheel drive vehicle with the motor 108 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, it may be a vehicle equipped with in-wheel motors for each wheel.

[0042] The battery pack 10 is composed of multiple battery modules 11. In this embodiment, as an example, 10 battery modules 11 are provided. Specifically, 5 battery modules 11 are arranged in the longitudinal direction of the vehicle on the right side of the vehicle 100, and 5 battery modules 11 are arranged in the longitudinal direction of the vehicle on the left side of the vehicle 100. Furthermore, each battery module 11 is electrically connected.

[0043] Figure 3 is a schematic perspective view of the battery module 11. As shown in Figure 3, the battery module 11 is formed in a roughly rectangular parallelepiped shape with the vehicle width direction as the longitudinal direction. The outer shell of the battery module 11 is made of aluminum alloy. For example, the outer shell of the battery module 11 is formed by joining aluminum die-cast parts to both ends of an aluminum alloy extruded 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, busbars (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 longitudinal direction is, for example, 150 mm to 250 mm, and the height MH in the vehicle vertical direction is, for example, 80 mm to 110 mm.

[0046] Figure 4 is a plan view of the battery module 11 with the top cover removed. As shown in Figure 4, multiple battery cells 20 are housed inside the battery module 11 in an arranged state. In this embodiment, as an example, 24 battery cells 20 are arranged in the front-rear direction of the vehicle and bonded to each other.

[0047] A flexible printed circuit board (FPC) 21 is placed on top of the battery cell 20. The flexible printed circuit board 21 is formed in a strip shape with the vehicle width direction as its longitudinal direction, and thermistors 23 are provided at both ends of the flexible printed circuit board 21. The thermistors 23 are not bonded to the battery cell 20, but are pressed toward the battery cell 20 by the upper cover of the battery module 11.

[0048] Furthermore, one or more cushioning materials (not shown) are housed inside the battery module 11. For example, the cushioning material is a thin, elastically deformable plate-like member, and is arranged between adjacent battery cells 20 with the arrangement direction of the battery cells 20 as the thickness direction. In this embodiment, as an example, cushioning material is arranged at both ends in the longitudinal direction and in the longitudinal center of the battery module 11.

[0049] Figure 5 is a schematic view of a battery cell 20 housed in a battery module 11, viewed from the thickness direction. As shown in Figure 5, the battery cell 20 is formed in a roughly rectangular plate shape, and an electrode body (not shown) is housed inside. The electrode body is composed of a positive electrode, a negative electrode, and a separator stacked together, and is sealed with a laminate film 22.

[0050] In this embodiment, as an example, the electrode housing is formed by folding and bonding an embossed sheet-like laminate film 22. While both a single-cup embossed structure (with one embossed area) and a double-cup embossed structure (with two embossed areas) can be employed, this embodiment uses a single-cup embossed structure with a fold depth of approximately 8mm to 10mm.

[0051] The upper ends of both longitudinal ends of the battery cell 20 are bent, and the corners form the outer shape. In addition, the upper end of the battery cell 20 is bent, and a fixing tape 24 is wrapped around the upper end of the battery cell 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 a position offset below the vertical center of the battery cell 20. The terminals 26 are joined to a busbar (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, 530mm~600mm, 600mm~700mm, 700mm~800mm, 800~900mm, and 1000mm or more. The length CW2 of the area where the electrode body is housed is, for example, 500mm~520mm, 600mm~700mm, 700mm~800mm, 800~900mm, and 1000mm or more. The height CH of the battery cell 20 is, for example, 80mm~110mm and 110mm~140mm. The thickness of the battery cell 20 is 5.0mm~7.0mm, 7.0mm~9.0mm, and 9.0mm~11.0mm. The height TH of the terminal 26 is 40mm~50mm, 50mm~60mm, and 60mm~70mm. [Explanation of Symbols]

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

Claims

1. The first step involves supplying an electrolyte solution to the internal space of the outer casing that houses the electrode body, The second step includes supplying the electrolyte extracted from the internal space of the outer casing back into the internal space of the outer casing, A method for manufacturing a battery, comprising the second step of removing air bubbles generated by contact with the electrode body contained in the electrolyte taken out from the internal space of the outer casing.

2. The method for manufacturing a battery according to claim 1, wherein the second step includes circulating the electrolyte.

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

4. The method for manufacturing a battery according to claim 1 or claim 2, wherein the amount of electrolyte in the internal space of the outer casing is such that more than half of the electrode body is submerged.

5. A first supply unit that supplies electrolyte to the internal space of the outer casing housing the electrode body, It includes a second supply unit that supplies the electrolyte extracted from the internal space of the outer casing back into the internal space of the outer casing, The battery manufacturing apparatus includes a second supply unit, which includes a defoaming unit that removes bubbles generated by contact between the electrolyte solution taken from the internal space of the outer casing and the electrode body.

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