Battery manufacturing method

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 Art

[0002] In the manufacturing process of a battery using a liquid electrolyte (electrolytic solution), a liquid injection operation is performed to allow the electrolytic solution to penetrate into an electrode containing an electrode active material. The electrode of a battery may be subjected to a pressing process at 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 a cause of reducing 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 using a groove provided on the surface of an electrode or a separator as a flow path for the electrolytic solution.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The method described in Patent Document 1 requires a step of providing a groove on the surface of an electrode or a separator, so there is a risk of reducing the efficiency of the entire battery manufacturing process. In addition, there is a risk of reducing the energy density of the battery by providing a groove in the electrode. One embodiment of the present disclosure aims to provide a novel method for manufacturing a battery in which the efficiency of the liquid injection operation of the electrolytic solution is improved.

Means for Solving the Problems

[0006] Means for solving the above problems include the following embodiments. <1> A process of arranging an electrode body and a plate with grooves formed on its surface in the internal space of the outer casing, A method for manufacturing a battery, comprising the step of supplying an electrolyte to the outer casing such that at least a portion of the electrode body and the plate are immersed in the electrolyte. <2> The direction of the grooves in the aforementioned plate is perpendicular to the liquid surface. <1> The battery manufacturing method described above. <3> The grooved surface of the plate is in contact with the end face of the electrode body. <1> or <2> The battery manufacturing method described above. <4> This includes moving at least a portion of the electrolyte to a region above the liquid surface along the grooves of the plate, <1> ~ <3> A method for manufacturing a battery as described in any one of the items. <5> This includes reducing the internal space of the exterior body, <1> ~ <4> A method for manufacturing a battery as described in any one of the items. [Effects of the Invention]

[0007] According to one embodiment of the present disclosure, a novel method for manufacturing a battery is provided in which the efficiency of the electrolyte injection process 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 components are not limited thereto.

[0010] The battery manufacturing method disclosed herein is A process of arranging an electrode body and a plate with grooves formed on its surface in the internal space of the outer casing, The process includes supplying an electrolyte to the outer casing such that at least a portion of the electrode body and plate are immersed in the electrolyte.

[0011] When electrolyte is supplied to the internal space of the outer casing, any portion of the supplied electrolyte that is not immediately absorbed by the electrode remains in the internal space of the outer casing. The waiting time required for the electrolyte solution retained in the internal space of the outer casing to be absorbed by the electrode body can reduce work efficiency. In particular, if the electrolyte solution is supplied in multiple stages, a long waiting time can easily lead to a decrease in work efficiency.

[0012] In contrast, the method of the present disclosure involves arranging a plate having grooves on its surface together with the electrode body in the internal space of the outer casing. The grooves in this 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 opportunity for contact between the electrode body and the electrolyte is increased, and the waiting time until the electrolyte is absorbed by the electrode body is shortened. Furthermore, since the method of the present disclosure can be implemented without processing the electrode body, it has high versatility.

[0013] Hereinafter, the step of disposing an electrode body and a plate having grooves formed on its surface in the internal space of the exterior body is also referred to as "Step 1", and the step of supplying an electrolytic solution to the exterior body so that at least a part of the electrode body and the plate are immersed in the electrolytic solution is also referred to as "Step 2".

[0014] (Step 1) In Step 1, an electrode body and a plate having grooves formed on its surface are disposed in the internal space of the exterior body. The type of the exterior body is not particularly limited, and known exterior bodies such as a bag-shaped structure obtained by joining the periphery of a flexible sheet and a metal can can be used. The electrode body includes a laminate composed of a positive electrode, a separator, and a negative electrode. Examples of the form of the electrode body include a state in which a plurality of cut laminates having a predetermined dimension are overlapped, and a state in which a long laminate is wound. The electrode body is preferably disposed in the internal space of the exterior body such that the end face of the electrode body (the portion where the cross section of the electrode is exposed and serves as the inlet of the main penetration path of the electrolytic solution) is located on the side portion of the electrode body.

[0015] As the plate, a plate having grooves formed on its surface that can induce the movement of the electrolytic solution by capillary action can be used without particular limitation. From the viewpoint of efficiently absorbing the electrolytic solution into the electrode body, the plate is preferably disposed in the internal space of the exterior body in a state where the surface on which the grooves are formed is in contact with the end face of the electrode body. 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 outer casing together with the electrode body. From the viewpoint of promoting the movement of the electrolyte and ease of removal from the outer casing, it is preferable that the dimension L1 in the long side direction of the plate and the dimension L2 in the direction of gravity of the electrode body when placed in the internal space of the outer casing satisfy the condition L1 ≥ L2.

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

[0018] In step 2, of the electrolyte supplied to the outer casing, the portion not absorbed by the electrode body immediately after supply remains in the internal space of the outer casing. Therefore, the system waits until the electrolyte remaining in the internal space of the outer casing is absorbed by the electrode body. During this time, at least a portion of the electrolyte moves along the grooves of the plate to a region above the liquid surface.

[0019] The method disclosed herein may include reducing the internal space of the outer casing. When the internal space of the outer casing is under reduced pressure, the movement of the electrolyte along the grooves of the plate is promoted, and the absorption of the electrolyte into the electrode body tends to be promoted.

[0020] After the design amount of electrolyte has penetrated the electrode body, the plate is removed from the outer casing and the opening of the outer casing is closed. The method for closing the opening of the outer casing is not particularly limited and can be done by known methods.

[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. As shown in Figure 1, the electrode body 12 and the plate 13 with grooves formed on its surface are arranged in the internal space of the outer casing 11. The electrode body 12 has an end face on its side, and the plate 13 is positioned so as to be in contact with the end face of the electrode body 12. The plate 13 has grooves (not shown) formed perpendicular to the liquid surface on the surface that is in contact with the end face of the electrode body 12. The internal space of the outer casing 11 contains the portion of the supplied electrolyte 14 that is not absorbed by the electrode body 12 immediately after supply. The electrode body 12 and the plate 13 are partially immersed in the electrolyte 14. At least a portion of the electrolyte 14 that remains in the internal space of the outer casing 11 moves upward along the grooves of the plate 13 by 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 the region above the liquid surface of the electrolyte 14 and is absorbed by the electrode body 12. Once the electrolyte 14 has been sufficiently absorbed by the electrode body 12, the process of supplying the electrolyte 14 to the internal space of the outer casing 11 is repeated as needed. Once the designed amount of electrolyte 14 has been supplied to the outer casing 11, the opening of the outer casing 11 is sealed.

[0022] 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, the battery 10 may be a battery (so-called laminate battery) that has an outer casing 11 obtained by joining the periphery of a laminate film. The exterior body 11 may consist of one component or two or more components.

[0023] (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.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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.

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

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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.

[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, busbars (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 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.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] 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.

[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 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.

[0046] 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]

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

Claims

1. A process of arranging an electrode body and a plate with grooves formed on its surface in the internal space of the outer casing, A step of supplying electrolyte to the outer casing such that at least a portion of the electrode body and the plate are immersed in the electrolyte, A method for manufacturing a battery, comprising the step of removing the plate from the outer casing.

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

3. The method for manufacturing a battery according to claim 1 or claim 2, wherein the grooved surface of the plate is in contact with the end face of the electrode body.

4. A method for manufacturing a battery according to claim 1 or claim 2, comprising moving at least a portion of the electrolyte to a region above the liquid surface along the grooves of the plate.

5. A method for manufacturing a battery according to claim 1 or claim 2, comprising reducing the internal space of the outer casing.

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