Battery manufacturing method

Abstract

The present disclosure relates to a novel method for manufacturing a battery that improves the efficiency of an electrolyte injection operation. This method for manufacturing a battery comprises: a step in which an electrode body (12) and a plate (13) having a groove formed on the surface thereof are disposed in the internal space of an exterior body (11); and a step for supplying an electrolyte solution (14) to the exterior body (11) such that at least a part of the electrode body (12) and the plate (13) are immersed in the electrolyte solution (141).

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 (electrolyte solution), a liquid injection operation is performed to allow the electrolyte solution to permeate into electrodes including an electrode active material.

[0003] The battery electrodes are sometimes pressed at high pressure to increase the energy density. When the electrode is pressed to increase the packing density of the electrode active material in the electrode, the permeability of the electrolyte decreases. The decrease in the permeability of the electrolyte becomes a cause of the decrease in the efficiency of the injection operation.

[0004] As a measure to improve the permeability of the electrolyte during the injection operation, Japanese Patent Application Laid-Open No. 2002-15773 proposes a technique of using grooves provided on the surface of an electrode or a separator as a flow path for the electrolyte.

[0005] The method described in Japanese Patent Application Laid-Open No. 2002-15773 requires a process of providing grooves on the surface of an electrode or a separator, so the efficiency of the entire battery manufacturing process may be reduced. In addition, the energy density of the battery may be reduced due to the grooves provided on the electrode. Summary of the invention

[0006] In view of the above circumstances, an object of one embodiment of the present disclosure is to provide a novel method for manufacturing a battery that improves the efficiency of an electrolyte injection operation.

[0007] Means for solving the above-mentioned problems include the following embodiments.

[0008] <1> A method for manufacturing a battery includes: a step of arranging an electrode body and a plate having grooves formed on the surface in the internal space of an outer casing; and a step of supplying an electrolyte to the outer casing in such a manner that at least a portion of the electrode body and the plate are immersed in the electrolyte.

[0009] <2> according to <1> In the battery manufacturing method, the direction of the grooves of the plate is perpendicular to the liquid surface.

[0010] <3> according to <1> or <2> In the above-mentioned method for manufacturing a battery, the surface of the plate having the groove formed thereon is in contact with the end surface of the electrode body.

[0011] <4> according to <1> ~ <3> The method for manufacturing a battery as described above includes: moving at least a portion of the electrolyte solution along the grooves of the plate to a region above a liquid surface.

[0012] <5> according to <1> ~ <4> The method for manufacturing a battery according to any one of the above aspects includes: reducing the pressure of the internal space of the outer casing. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a diagram schematically showing an example of a method for manufacturing a battery.

[0014] Figure 2 This is a diagram schematically showing an example of application of a battery module to an electric vehicle.

[0015] Figure 3 This is a diagram schematically showing an example of the configuration of a battery module.

[0016] Figure 4 This is a diagram schematically showing an example of the configuration of a battery module.

[0017] Figure 5 This is a diagram schematically showing an example of the configuration of battery cells included in a battery module. DETAILED DESCRIPTION

[0018] In the present disclosure, a numerical range expressed using "to" means a range including the numerical values ​​described before and after "to" as a minimum value and a maximum value, respectively.

[0019] In the numerical range recorded in stages in the present disclosure, the upper limit or lower limit recorded in a certain numerical range can also be replaced by the upper limit or lower limit of other numerical ranges recorded in stages. In the numerical range recorded in the present disclosure, the upper limit or lower limit recorded in a certain numerical range can also be replaced by the value shown in the embodiment.

[0020] In the present disclosure, the term "step" includes not only an independent step but also a step that cannot be clearly distinguished from other steps as long as the intended purpose of the step is achieved.

[0021] In the present disclosure, when an embodiment 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 sizes of components in each figure are conceptual, and the relative relationship between the sizes of the components is not limited to this.

[0022] The method for manufacturing a battery disclosed herein includes: placing an electrode body and a plate having grooves formed on the surface in an internal space of an outer casing; and 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.

[0023] When the electrolyte solution is supplied to the internal space of the outer casing, a portion of the supplied electrolyte solution that is not absorbed by the electrode assembly immediately after the supply is accumulated in the internal space of the outer casing.

[0024] The waiting time until the electrolyte solution accumulated in the internal space of the outer casing is absorbed by the electrode body may be a major factor that reduces the working efficiency. In particular, when the electrolyte solution is supplied in multiple times, if the waiting time is long, the working efficiency is likely to be reduced.

[0025] In contrast, in the method disclosed herein, a plate having grooves on its surface is disposed in the internal space of the outer body together with the electrode body. The grooves of the plate induce capillary action of the electrolyte, and at least a portion of the electrolyte moves to a position above the liquid surface. As a result, the contact opportunity between the electrode body and the electrolyte is increased, and the waiting time until the electrolyte is absorbed by the electrode body is shortened.

[0026] Furthermore, the method disclosed herein can be implemented without processing the electrode body, and therefore has high versatility.

[0027] Hereinafter, the process of configuring the electrode body and the plate having grooves formed on the surface in the internal space of the outer casing will also be referred to as "process 1", and the process of supplying the electrolyte to the outer casing in a manner that at least a portion of the electrode body and the plate are immersed in the electrolyte will also be referred to as "process 2".

[0028] (Process 1)

[0029] In step 1, the electrode body and the plate having grooves formed on the surface are arranged in the internal space of the outer casing.

[0030] The type of the outer casing is not particularly limited, and a known outer casing such as a bag-shaped structure obtained by bonding the periphery of a flexible sheet, or a metal can can be used.

[0031] The electrode body includes a laminated body composed of a positive electrode, a separator, and a negative electrode. Examples of the form of the electrode body include a state where a plurality of laminated bodies cut into predetermined sizes are stacked, a state where a long laminated body is wound, and the like.

[0032] The electrode body is preferably disposed in the internal space of the outer casing so that the end surface of the electrode body (a portion where the cross section of the electrode is exposed and serves as an inlet of a main permeation path of the electrolyte) is located on the side of the electrode body.

[0033] As the plate, any plate having grooves formed on the surface thereof that can induce the migration of the electrolyte by capillary phenomenon can be used without particular limitation.

[0034] From the viewpoint of allowing the electrode body to absorb the electrolyte efficiently, the plate is preferably disposed in the internal space of the outer casing in a state where the surface having the grooves is in contact with the end surface of the electrode body.

[0035] The direction of the grooves of the plate disposed in the internal space of the outer casing is preferably perpendicular to the liquid surface.

[0036] The number of panels arranged in the internal space of the exterior body may be one or two or more.

[0037] The size of the plate is not particularly limited as long as it can be arranged in the internal space of the outer body together with the electrode body. From the perspective of promoting the movement of the electrolyte and the ease of removal from the outer body, the dimension L1 of the long side direction of the plate and the dimension L2 of the electrode body in the gravity direction in the state of being arranged in the internal space of the outer body preferably satisfy the condition of L1 ≥ L2.

[0038] (Process 2)

[0039] In step 2, the electrolyte solution is supplied to the outer casing so that at least a portion of the electrode assembly and the plate are immersed in the electrolyte solution.

[0040] The method of supplying the electrolyte solution to the outer casing is not particularly limited, and the electrolyte solution can be supplied by a known method.

[0041] The electrolyte solution may be supplied once or multiple times.

[0042] The part of the electrolyte supplied to the outer body in step 2 that is not absorbed by the electrode body immediately after supply is retained in the inner space of the outer body. Therefore, the electrolyte retained in the inner space of the outer body is absorbed by the electrode body. During this period, at least a part of the electrolyte moves along the groove of the plate to the area above the liquid surface.

[0043] The method of the present disclosure may further include: depressurizing the internal space of the outer casing. When the internal space of the outer casing is in a depressurized state, the movement of the electrolyte along the grooves of the plate is promoted, and absorption of the electrolyte into the electrode body tends to be promoted.

[0044] After the designed amount of electrolyte solution has completely penetrated the electrode assembly, 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 carried out by a known method.

[0045] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

[0046] Figure 1 This is a diagram schematically showing an example of a method for manufacturing a battery.

[0047] like Figure 1 As shown, an electrode body 12 and a plate 13 having grooves formed on the surface are arranged in the internal space of an outer casing 11 .

[0048] Electrode body 12 has an end surface on the side, and plate 13 is arranged to contact the end surface of electrode body 12. 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 electrode body 12.

[0049] The portion of the supplied electrolyte 14 that is not absorbed by the electrode body 12 immediately after the supply is accumulated in the internal space of the outer casing 11. The electrode body 12 and the plate 13 are partially immersed in the electrolyte 14, respectively.

[0050] At least a portion of the electrolyte 14 retained in the internal space of the outer casing 11 moves to a position above the liquid surface along the grooves of the plate 13 due to the capillary phenomenon. The electrolyte 14 moving along the grooves of the plate 13 contacts the end surface of the electrode body 12 in a region above the liquid surface of the electrolyte 14 and is absorbed by the electrode body 12.

[0051] After the electrolyte solution 14 is sufficiently absorbed by the electrode body 12 , the step of supplying the electrolyte solution 14 to the internal space of the outer casing 11 is repeated as necessary.

[0052] After a designed amount of electrolyte solution 14 is supplied to the outer casing 11 , the opening of the outer casing 11 is sealed.

[0053] In one embodiment, the material constituting the outer casing 11 may be a laminate (so-called laminate film) having a metal layer including a metal such as aluminum and a heat seal layer including a resin melted by heating. That is, the battery 10 may be a battery (so-called laminate battery) having an outer casing 11 obtained by bonding the periphery of a laminate film.

[0054] The exterior body 11 may be composed of one member or may be composed of two or more members.

[0055] (Battery)

[0056] The type of battery produced by the method of the present disclosure is not particularly limited.

[0057] Specific examples of the battery include secondary batteries such as lithium ion secondary batteries, lead storage batteries, nickel-metal hydride storage batteries, nickel-cadmium storage batteries, nickel-iron storage batteries, nickel-zinc storage batteries, silver oxide-zinc storage batteries, and cobalt-titanium-lithium secondary batteries.

[0058] From the viewpoint of energy density, versatility, etc., the battery may be a lithium ion secondary battery.

[0059] 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 solution.

[0060] The positive electrode includes, for example, a current collector and a positive electrode layer disposed on the current collector. The positive electrode layer contains a positive electrode active material.

[0061] The positive electrode includes, for example, a current collector and a positive electrode layer disposed on the current collector. The positive electrode layer contains a positive electrode active material.

[0062] As the positive electrode active material, a composite oxide composed of lithium and a transition metal, and other metals that can be arbitrarily contained (hereinafter also referred to as a lithium transition metal composite oxide) can be listed. As transition metals and other metals, Ni, Co, Mn, Al, B, Mg, Ti, V, Cr, Fe, Cu, Zn, Ga, Sr, Zr, Nb, In, Sn, Ta, W, etc. can be listed.

[0063] Examples of the lithium transition metal composite oxide include layered lithium transition metal composite oxides, spinel lithium transition metal composite oxides, and olivine lithium transition metal composite oxides.

[0064] Examples of layered lithium transition metal composite oxides include lithium transition metal composite oxides containing at least one transition metal selected from Ni, Co, and Mn. Specifically, examples include LiNi a Co b Mn c A compound represented by the structural formula O2 (a, b, c are numbers greater than 0 and less than 1, respectively, and a+b+c=1), and a compound to 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.

[0065] Specific examples of spinel-type lithium transition metal composite oxides include LiMn 2 O 4 .

[0066] Specific examples of the olivine-type lithium transition metal composite oxide include LiMPO 4 (M: Fe, Co, Ni, or Mn).

[0067] The positive electrode active material contained in the positive electrode layer may be used alone or in combination of two or more.

[0068] The positive electrode layer may contain components such as a conductive auxiliary agent and a binder in addition to the positive electrode active material.

[0069] Examples of the material of the current collector constituting the positive electrode include aluminum, aluminum alloys, nickel, titanium, stainless steel, etc. Examples of the shape of the current collector include foil and mesh.

[0070] The negative electrode includes, for example, a current collector and a negative electrode layer disposed on the current collector and containing a negative electrode active material.

[0071] 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).

[0072] The negative electrode layer may contain components such as a conductive auxiliary agent and a binder in addition to the negative electrode active material.

[0073] Examples of the material of the current collector constituting the negative electrode include copper, copper alloys, nickel, titanium, stainless steel, etc. Examples of the shape of the current collector of the negative electrode include foil and mesh.

[0074] Examples of the separator include nonwoven fabrics, cloths, and microporous films mainly composed of polyolefins such as polyethylene and polypropylene. When a solid electrolyte is used in a lithium ion secondary battery, a separator may not be used.

[0075] As the electrolyte solution, an electrolyte solution obtained by dissolving a known lithium salt such as LiPF 6 in an organic solvent can be used without particular limitation.

[0076] The battery of the present disclosure can be mounted on an electric vehicle. Hereinafter, an example in which the battery of the present disclosure is applied to an electric vehicle will be described with reference to the accompanying drawings. In the following description, the "battery unit 20" corresponds to the battery of the present disclosure.

[0077] Figure 2 1 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. Figure 2 As shown, the vehicle 100 is an electric vehicle (BEV) equipped with a battery pack 10 under the floor. In addition, the arrows UP, FR, and LH in each figure respectively indicate the upper side in the vehicle vertical direction, the front side in the vehicle front-back direction, and the left side in the vehicle width direction. When the front-back, left-right, up-down and down directions are used for description, unless otherwise specified, they indicate the front-back in the vehicle front-back direction, the left-right in the vehicle width direction, and the up-down in the vehicle vertical direction.

[0078] As an example, the vehicle 100 of the present embodiment is provided with a DC / DC converter 102, an electric compressor 104, and a PTC (Positive Temperature Coefficient) heater 106 at a position closer to the front side of the vehicle than the battery pack 10. In addition, a motor 108, a gear box 110, an inverter 112, and a charger 114 are provided at a position closer to the rear side of the vehicle than the battery pack 10.

[0079] The DC current output from battery pack 10 is regulated in voltage by DC / DC converter 102 and then supplied to electric compressor 104, PTC heater 106, inverter 112, etc. In addition, by supplying power to motor 108 via inverter 112, the rear wheels rotate and vehicle 100 travels.

[0080] A charging port 116 is provided at the right side of the rear portion of the vehicle 100. By connecting a charging plug of an external charging device (not shown) to the charging port 116, electric power can be stored in the battery pack 10 via the charger 114.

[0081] The configuration and structure of each component constituting the vehicle 100 are not limited to the above-mentioned configuration. For example, it can also be applied to a hybrid vehicle (HV: Hybrid Vehicle) or a plug-in hybrid vehicle (PHEV: Plug-in Hybrid Electric Vehicle) equipped with an engine. In addition, in the present embodiment, the motor 108 is mounted on the rear of the vehicle and is a rear-wheel drive vehicle, but it is not limited to this. The motor 108 may be mounted on the front of the vehicle and is a front-wheel drive vehicle, or a pair of motors 108 may be mounted on the front and rear of the vehicle. In addition, it may be a vehicle with an in-wheel motor on each wheel.

[0082] The battery pack 10 is configured to include a plurality of battery modules 11. In the present embodiment, as an example, 10 battery modules 11 are provided. Specifically, on the right side of the vehicle 100, five battery modules 11 are arranged along the front-rear direction of the vehicle, and on the left side of the vehicle 100, five battery modules 11 are arranged along the front-rear direction of the vehicle. In addition, each battery module 11 is electrically connected.

[0083] Figure 3 1 is a schematic three-dimensional diagram of the battery module 11. Figure 3 As shown, the battery module 11 is formed into a substantially rectangular parallelepiped shape with the vehicle width direction as the length direction. In addition, 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 the two ends of an aluminum die casting and an aluminum alloy extrusion by laser welding or the like.

[0084] 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 described later is connected to the connector 14. Bus bars (not shown) are welded to both ends of the battery module 11 in the vehicle width direction.

[0085] The battery module 11 has a length MW in the vehicle width direction of, for example, 350 mm to 600 mm, a length ML in the vehicle front-rear direction of, for example, 150 mm to 250 mm, and a height MH in the vehicle vertical direction of, for example, 80 mm to 110 mm.

[0086] Figure 4 1 is a plan view of the battery module 11 with the upper cover removed. Figure 4 As shown, a plurality of battery cells 20 are accommodated in an aligned state inside the battery module 11. In the present embodiment, as an example, 24 battery cells 20 are aligned in the vehicle front-rear direction and bonded to each other.

[0087] A flexible printed circuit (FPC) 21 is provided on the battery cell 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 at both ends of the flexible printed circuit 21. The thermistor 23 is not bonded to the battery cell 20 but is pressed toward the battery cell 20 by the upper cover of the battery module 11.

[0088] In addition, one or more buffers (not shown) are accommodated inside the battery module 11. For example, the buffer is a thin plate-shaped member that can be elastically deformed, 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, buffers are arranged at both ends and the center of the battery module 11 in the longitudinal direction.

[0089] Figure 5 This is a schematic diagram of the battery cell 20 housed in the battery module 11 as viewed from the thickness direction. Figure 5 As shown, the battery cell 20 is formed in a substantially rectangular plate shape, and an electrode body (not shown) is accommodated therein. The electrode body is formed by stacking a positive electrode, a negative electrode, and a separator, and is sealed by a laminate film 22 .

[0090] In this embodiment, as an example, the electrode body receiving portion is formed by folding and laminating the sheet-shaped laminate film 22 after embossing. The laminate film 22 can adopt any one of a single-cup embossing structure with embossing at one place and a double-cup embossing structure with embossing at two places. The laminate film 22 in one embodiment is a single-cup embossing structure with a drawing depth of about 8 mm to 10 mm.

[0091] The upper ends of the battery cell 20 at both ends in the longitudinal direction are bent, and the corners become the outer shape. In addition, the upper end of the battery cell 20 is bent, and the fixing band 24 is wound around the upper end of the battery cell 20 along the longitudinal direction.

[0092] Terminals (tabs) 26 are provided at both ends of the battery cell 20 in the longitudinal direction. In the present 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 bus bars (not shown) by laser welding or the like.

[0093] For example, the length CW1 of the battery cell 20 in the vehicle width direction is 530mm~600mm, 600mm~700mm, 700mm~800mm, 800~900mm or more than 1000mm, the length CW2 of the area accommodating the electrode body is 500mm~520mm, 600mm~700mm, 700mm~800mm, 800~900mm or more than 1000mm, the height CH is 80mm~110mm or 110mm~140mm, the thickness is 5.0mm~7.0mm, 7.0mm~9.0mm or 9.0mm~11.0mm, and the height TH of the terminal 26 is 40mm~50mm, 50mm~60mm or 60mm~70mm.

Claims

1. A method for manufacturing a battery, comprising: A step of arranging an electrode body and a plate having grooves formed on the surface in the internal space of the outer casing; as well as A step of supplying an electrolyte solution to the outer casing so that at least a portion of the electrode assembly and the plate are immersed in the electrolyte solution.

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

3. The method for manufacturing a battery according to claim 1 or 2, The surface of the plate having the grooves formed thereon is in contact with the end surface of the electrode body.

4. The method for manufacturing a battery according to claim 1 or 2, The manufacturing method of the battery comprises: At least a portion of the electrolyte solution is moved along the grooves of the plate to a region above the liquid surface.

5. The method for manufacturing a battery according to claim 1 or 2, The manufacturing method of the battery comprises: The internal space of the outer body is decompressed.

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