Battery manufacturing method and battery manufacturing apparatus

Abstract

The present disclosure provides a novel method for manufacturing a battery and a device for manufacturing a battery that improve the efficiency of an electrolyte injection operation. The method for manufacturing a battery includes: a first step in which an electrolyte solution is supplied to an inner space of an exterior body in which an electrode body is housed; and a second step in which the electrolyte solution extracted from the inner space of the exterior body is supplied to the inner space of the exterior body, the second step including removing air bubbles contained in the electrolyte solution extracted from the inner space of the exterior body.

Description

Technical Field

[0001] The present disclosure relates to a method for manufacturing a battery and an apparatus for manufacturing a battery. 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 to supply the electrolytic solution into an outer casing that houses an electrode body and to allow the electrolytic solution to permeate the electrode body.

[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 countermeasure to improve the permeability of the electrolyte during the injection operation, the following countermeasure is proposed in Patent Document 1: by continuously supplying the electrolyte to the outer body containing the electrode body while discharging the electrolyte, a certain flow rate of electrolyte is allowed to flow. According to this method, the electrolyte collides with the electrode body while causing turbulence, and the penetration rate of the electrolyte into the electrode body is increased.

[0005] In the method described in Patent Document 1, the electrolyte in a flowing state may contain bubbles generated by contact with the electrode body. In this case, the bubbles contained in the electrolyte may prevent the electrolyte from penetrating into the electrode body. 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 battery manufacturing method and battery manufacturing apparatus that improve the efficiency of electrolyte injection work.

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

[0008] <1> A method for manufacturing a battery, comprising:

[0009] a first step of supplying an electrolyte solution to an internal space of an outer casing accommodating an electrode assembly; and

[0010] a second step of supplying the electrolyte solution taken out from the internal space of the outer casing to the internal space of the outer casing,

[0011] The second step includes removing bubbles contained in the electrolyte solution taken out from the internal space of the outer casing.

[0012] <2> according to <1> In the battery manufacturing method, the second step includes: circulating the electrolyte.

[0013] <3> according to <1> or <2> In the battery manufacturing method, the bubbles are removed by using a vacuum degassing device.

[0014] <4> according to <1> ~ <3> In the method for manufacturing a battery described above, the amount of the electrolyte solution in the internal space of the outer casing is an amount sufficient to immerse at least half of the electrode body.

[0015] <5> A battery manufacturing device, comprising:

[0016] a first supply unit that supplies an electrolyte solution to an internal space of an outer casing that accommodates the electrode assembly; and

[0017] a second supply unit configured to supply the electrolyte solution taken out from the internal space of the outer casing to the internal space of the outer casing,

[0018] The second supply unit includes a degassing unit that removes bubbles included in the electrolyte solution taken out from the internal space of the outer casing. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a diagram schematically showing an example of a method for manufacturing a battery.

[0020] Figure 2 This is a diagram schematically showing an example of application of a battery module to an electric vehicle.

[0021] Figure 3 This is a diagram schematically showing an example of the configuration of a battery module.

[0022] Figure 4 This is a diagram schematically showing an example of the configuration of a battery module.

[0023] Figure 5 This is a diagram schematically showing an example of the configuration of battery cells included in a battery module. DETAILED DESCRIPTION

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] <Battery Manufacturing Method>

[0029] The manufacturing method of the battery disclosed herein comprises:

[0030] a first step of supplying an electrolyte solution to an internal space of an outer casing accommodating an electrode assembly; and

[0031] a second step of supplying the electrolyte solution taken out from the internal space of the outer casing to the internal space of the outer casing,

[0032] The second step includes removing bubbles contained in the electrolyte solution taken out from the internal space of the outer casing.

[0033] When the electrolyte is supplied to the internal space of the outer body, the part of the supplied electrolyte that is not absorbed by the electrode body immediately after supply is retained in the internal space of the outer body. In the previous method, the operation is stopped and the standby is performed until the electrolyte retained in the internal space of the outer body is absorbed by the electrode body through capillary phenomena, etc. This standby time may become the main reason for the reduction in operating efficiency. In particular, when the electrolyte is supplied in multiple times, when the above-mentioned standby time is long, the operating efficiency is likely to be reduced.

[0034] In contrast, in the method of the present disclosure, in addition to the first step of supplying the electrolyte to the internal space of the outer casing, the second step of supplying the electrolyte taken out from the internal space of the outer casing to the internal space of the outer casing is performed.

[0035] By performing the second step, the electrolyte in the internal space of the outer casing can be made to flow. When the electrolyte in the outer casing is in a flowing state, the penetration rate into the electrode body can be increased compared to a case where the electrolyte is in a stationary (stagnant) state.

[0036] Furthermore, in the method of the present disclosure, the second step includes removing bubbles contained in the electrolyte solution taken out from the internal space of the outer casing.

[0037] The electrolyte solution supplied to the internal space of the outer casing in the first step may contain bubbles generated by contact with the electrode assembly disposed in the outer casing. The bubbles contained in the electrolyte solution may become a factor that prevents the electrolyte solution from permeating into the electrode assembly.

[0038] In the method of the present disclosure, bubbles contained in the electrolyte solution taken out from the outer casing are removed before the electrolyte solution is supplied to the outer casing again. This makes it possible to maintain good permeability of the electrolyte solution to the electrode body.

[0039] (1st step)

[0040] In the first step, an electrolyte solution is supplied to the internal space of the outer casing that houses the electrode assembly.

[0041] The supply of the electrolyte in the first step is performed, for example, using a first pipe connecting a tank storing the electrolyte and a first supply port provided in the outer casing.

[0042] The amount of the electrolyte supplied to the internal space of the outer casing in the first step may be the same as, less than, or more than the designed amount of the electrolyte contained in the battery manufactured by the method of the present disclosure.

[0043] When the supply amount of the electrolyte solution is smaller than the designed amount of the electrolyte solution, for example, the supply of the electrolyte solution in the first step is performed a plurality of times.

[0044] When the supply amount of the electrolyte solution is larger than the designed amount of the electrolyte solution, for example, the excess amount is removed from the electrolyte solution taken out from the outer casing in the second step. The removed electrolyte solution can be reused in the manufacture of the battery.

[0045] In the method disclosed herein, since the electrolyte is taken out from the outer body in the second step, the amount of electrolyte supplied to the inner space of the outer body in the first step can be greater than the designed amount. Thus, the contact area between the electrolyte and the electrode body can be increased, and the electrolyte can be efficiently infiltrated into the electrode body.

[0046] The portion of the electrolyte supplied in the first step that is not absorbed by the electrode body is retained in the internal space of the outer casing. From the viewpoint of efficiently permeating the electrolyte into the electrode body, the amount of electrolyte retained in the internal space of the outer casing is preferably an amount that immerses more than half of the electrode body.

[0047] (Second step)

[0048] In the second step, the electrolyte solution taken out from the internal space of the outer casing is supplied to the internal space of the outer casing.

[0049] The supply of the electrolyte in the second step is performed, for example, using a second pipe connecting an electrolyte discharge port provided in the outer casing and a second electrolyte supply port provided in the outer casing.

[0050] The second step may include: circulating the electrolyte solution. That is, the step of supplying the electrolyte solution taken out from the internal space of the outer casing to the internal space of the outer casing may be continuously repeated.

[0051] The second step includes removing bubbles contained in the electrolyte solution taken out from the internal space of the outer casing.

[0052] The method for removing bubbles contained in the electrolyte is not particularly limited, and it can be carried out using a known degassing device. Examples of the degassing device include a vacuum degassing device, a centrifugal degassing device, and an ultrasonic degassing device, among which a vacuum degassing device is preferred.

[0053] From the viewpoint of efficiently performing the penetration of the electrolyte into the electrode assembly, the discharge port for taking out the electrolyte from the outer casing is preferably provided below the second supply port for supplying the electrolyte to the outer casing in the gravity direction.

[0054] From the viewpoint of efficiently allowing the electrolyte solution to permeate the electrode assembly, it is preferred that the second step be performed while decompressing the internal space of the outer casing.

[0055] The second step can also be performed using a power source such as a pump.

[0056] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

[0057] Figure 1 This is a diagram schematically showing an example of a method for manufacturing a battery.

[0058] Figure 1 The outer casing 11 shown has a first supply port 12, a second supply port 13, and a discharge port 14 for supplying or discharging the electrolyte. An electrode body 15 is arranged in the internal space of the outer casing 11.

[0059] The first supply port 12 is connected to a tank 16 storing an electrolytic solution via a first pipe 17 .

[0060] 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 .

[0061] A degassing device 19 for removing bubbles contained in the electrolyte is connected to the second pipe 18 .

[0062] The electrolyte 20 supplied from the tank 16 via the first pipe 17 is retained in the internal space of the outer casing 11. The electrolyte 20 contains bubbles (not shown) generated by contact with the electrode assembly 15 and the like.

[0063] The electrolyte 20 is taken out from the discharge port 14 of the outer casing 11 , and is supplied again to the internal space of the outer casing 11 from the second supply port 13 of the outer casing 11 through the second pipe 18 .

[0064] The electrolyte 20 taken out from the internal space of the outer casing 11 has bubbles removed by the degassing device 19 provided in the second pipe 18 before being supplied again to the internal space of the outer casing 11 .

[0065] After the electrolyte 20 is sufficiently absorbed by the electrode assembly 15 , the first step of supplying the electrolyte 20 from the tank 16 to the internal space of the exterior body 11 and the second step of supplying the electrolyte taken out from the exterior body 11 to the exterior body 11 are repeated as necessary.

[0066] After a designed amount of the electrolyte solution 20 is supplied to the outer casing 11 , the first supply port 12 , the second supply port 13 , and the discharge port 14 are sealed.

[0067] In one embodiment, the material constituting the outer casing 11 may be a laminate having a metal layer including a metal such as aluminum and a heat seal layer including a resin melted by heating (so-called laminate film). That is, the battery manufactured by the method disclosed herein may be a battery having an outer casing 11 obtained by bonding the periphery of a laminate film (so-called laminate battery).

[0068] The outer casing 11 may be Figure 1 Although it is composed of one member as shown, it may be composed of two or more members.

[0069] <Battery Manufacturing Apparatus>

[0070] The battery manufacturing device of the present disclosure includes:

[0071] a first supply unit that supplies an electrolyte solution to an internal space of an outer casing that accommodates the electrode assembly; and

[0072] a second supply unit configured to supply the electrolyte solution taken out from the internal space of the outer casing to the internal space of the outer casing,

[0073] The second supply unit includes a degassing unit that removes bubbles included in the electrolyte solution taken out from the internal space of the outer casing.

[0074] The configuration of the first supply unit in the device of the present disclosure is not particularly limited as long as it can supply the electrolyte solution to the internal space of the outer casing that accommodates the electrode assembly.

[0075] The first supply unit may include, for example, a first pipe that connects a tank storing the electrolyte solution and a first supply port provided in the outer casing.

[0076] 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 taken out from the internal space of the outer casing to the internal space of the outer casing.

[0077] The second supply unit may include, for example, a second pipe connecting a discharge port for taking out the electrolyte from the outer casing and a second supply port for resupplying the electrolyte to the outer casing.

[0078] The structure of the degassing section included in the second pipe is not particularly limited, and can be selected from known degassing devices.

[0079] For details and preferred embodiments of the method of using the device of the present disclosure, reference can be made to the contents described in the above-mentioned method of manufacturing the battery of the present disclosure.

[0080] (Battery)

[0081] The type of battery produced by the method of the present disclosure is not particularly limited.

[0082] 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.

[0083] From the viewpoint of energy density, versatility, etc., the battery may be a lithium ion secondary battery.

[0084] 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.

[0085] 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.

[0086] 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.

[0087] 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.

[0088] 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 O 2 A compound represented by a structural formula (a, b, c are respectively numbers greater than 0 and less than 1, 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.

[0089] Specific examples of the spinel lithium transition metal composite oxide include LiMn 2 O 4 .

[0090] Specific examples of the olivine-type lithium transition metal composite oxide include LiMPO 4 (M: Fe, Co, Ni or Mn).

[0091] The positive electrode active material contained in the positive electrode layer may be used alone or in combination of two or more.

[0092] The positive electrode layer may contain components such as a conductive auxiliary agent and a binder in addition to the positive electrode active material.

[0093] 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.

[0094] 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.

[0095] 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).

[0096] The negative electrode layer may contain components such as a conductive auxiliary agent and a binder in addition to the negative electrode active material.

[0097] 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.

[0098] 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.

[0099] As the electrolyte, LiPF can be used without particular limitation. 6 Such a known lithium salt is dissolved in an organic solvent to form an electrolyte solution.

[0100] 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.

[0101] 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.

[0102] 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.

[0103] 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.

[0104] 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.

[0105] 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.

[0106] 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.

[0107] 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.

[0108] 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.

[0109] 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.

[0110] 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.

[0111] 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.

[0112] 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.

[0113] 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 .

[0114] 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.

[0115] 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.

[0116] 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.

[0117] 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 first step of supplying an electrolyte solution to an internal space of an outer casing accommodating an electrode assembly; as well as a second step of supplying the electrolyte solution taken out from the internal space of the outer casing to the internal space of the outer casing, The second step includes removing bubbles contained in the electrolyte solution taken out from the internal space of the outer casing.

2. The method for manufacturing a battery according to claim 1, The second step comprises: The electrolyte is circulated.

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

4. The method for manufacturing a battery according to claim 1 or 2, The amount of the electrolyte solution in the internal space of the outer casing is an amount sufficient to immerse at least half of the electrode body.

5. A battery manufacturing device, comprising: a first supply unit for supplying an electrolyte to an internal space of an outer casing that accommodates the electrode assembly; as well as a second supply unit configured to supply the electrolyte solution taken out from the internal space of the outer casing to the internal space of the outer casing, The second supply unit includes a degassing unit that removes bubbles included in the electrolyte solution taken out from the internal space of the outer casing.

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