Method of manufacturing non-aqueous electrolyte secondary battery

Abstract

To provide a method of manufacturing a non-aqueous electrolyte secondary battery capable of shortening time to impregnate an electrode body with an electrolyte.SOLUTION: A method of manufacturing a non-aqueous electrolyte secondary battery includes the step of disposing a sheath body in such a manner that a direction of the sheath body in a length direction is longitudinal, injecting an electrolyte into the sheath body, impregnating an electrode body with the electrolyte, next disposing the sheath body while changing the direction of the sheath body in the length direction from longitudinal to lateral, and impregnating the electrode body with the electrolyte. When a dimension of the electrode body in the length direction of the sheath body is defined as H1 and when a level of the electrolyte comes to a position where a height from a lower end face of the electrode body stored in the sheath body is (1 / 4)×H1 or more to (3 / 4)×H1 or less, the direction of the sheath body in the length direction is changed from longitudinal to lateral.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a method for manufacturing a non-aqueous electrolyte secondary battery. [Background technology]

[0002] Japanese Patent Publication No. 2023-25424 (Patent Document 1) proposes a method for manufacturing a battery in which an electrode body is sealed with an outer casing, and an intermediate member having an unsealed portion for injecting electrolyte is placed so that the long side of the intermediate member is vertically downward, and electrolyte is allowed to penetrate into the intermediate member. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2023-25424 Summary of the Invention [Problem to be solved by the invention]

[0004] In the battery manufacturing method described in JP 2023-25424 A, the time required to impregnate the electrode body with the electrolyte solution is not sufficiently shortened, and the time required to manufacture the battery may be long. In particular, in the manufacture of large cells, the time required to impregnate the electrode body with the electrolyte solution tends to be long, and the time required to manufacture the battery tends to be long, so there is a demand for shortening the time required to impregnate the electrode body with the electrolyte solution.

[0005] An object of the present disclosure is to provide a method for producing a nonaqueous electrolyte secondary battery that can shorten the time required for impregnating an electrode assembly with an electrolyte solution. [Means for solving the problem]

[0006] [1] A method for manufacturing a nonaqueous electrolyte secondary battery including an exterior body, an electrolytic solution, and an electrode assembly within the exterior body, comprising: The longitudinal dimension of the exterior body is 200 mm or more, a step of housing an electrode assembly in the exterior housing; a step of placing the exterior body so that the longitudinal direction of the exterior body is oriented vertically, injecting the electrolyte into the exterior body, and impregnating the electrode body with the electrolyte; and then changing the orientation of the exterior body so that the longitudinal direction of the exterior body is oriented horizontally from the vertical direction, and impregnating the electrode body with the electrolyte; Including, a method for manufacturing a nonaqueous electrolyte secondary battery, wherein, when the height of the liquid surface of the electrolyte solution from the lower end surface of the electrode body housed in the exterior body is at least (¼)×H1 and not more than (¾)×H1, the longitudinal orientation of the exterior body is changed from vertical to horizontal, where H1 is the dimension of the electrode body in the longitudinal direction of the exterior body. [2] The method for producing a nonaqueous electrolyte secondary battery according to [1], wherein a liquid injection hole is provided in a side wall of the exterior body on the electrode terminal side. [3] The method for manufacturing a nonaqueous electrolyte secondary battery according to [1] or [2], wherein a liquid injection hole is provided in one of the side walls opposing each other in the longitudinal direction of the exterior body. [4] The method for producing a nonaqueous electrolyte secondary battery according to any one of [1] to [3], wherein the ratio of the dimension in the short direction to the dimension in the long direction of the exterior body is 0.4 or less. [5] The method for producing a nonaqueous electrolyte secondary battery according to any one of [1] to [4], wherein the longitudinal dimension of the exterior body exceeds 200 mm, and the longitudinal dimension of the exterior body of the electrode assembly is 200 mm or more. [6] The method for producing a nonaqueous electrolyte secondary battery according to any one of [1] to [5], wherein the electrode assembly is of a laminated type or a wound type. [Effects of the Invention]

[0007] According to the present disclosure, it is possible to provide a method for manufacturing a nonaqueous electrolyte secondary battery that can shorten the time required for impregnating an electrode assembly with an electrolyte solution. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view showing a battery. [Figure 2] FIG. 2 is a cross-sectional view of the battery as viewed from the Y-axis direction. [Figure 3] FIG. 3 is a schematic cross-sectional view showing the flow of the liquid injection impregnation step. [Figure 4] FIG. 4 is a schematic cross-sectional view illustrating a method for checking the liquid level. [Figure 5] FIG. 5 is a schematic diagram illustrating the longitudinal dimension of the electrode body. [Figure 6] FIG. 6 is a schematic cross-sectional view illustrating a liquid injection impregnation step not according to the present disclosure. [Figure 7] FIG. 7 is a schematic cross-sectional view illustrating the liquid injection impregnation step according to the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0009] <Method of manufacturing non-aqueous electrolyte secondary battery> A method for manufacturing a nonaqueous electrolyte secondary battery (hereinafter also referred to as a battery) according to the present disclosure includes a process of housing an electrode assembly in an exterior housing having a longitudinal dimension of 200 mm or more, an electrolyte solution therein, and an electrode assembly (hereinafter also referred to as a housing process), and a process of positioning the exterior housing containing the electrode assembly so that the longitudinal direction of the exterior housing is vertical, injecting electrolyte solution into the exterior housing to impregnate the electrode assembly with the electrolyte solution, and then changing the longitudinal direction of the exterior housing containing the electrode assembly so that the longitudinal direction of the exterior housing is horizontal, and impregnating the electrode assembly with the electrolyte solution (hereinafter also referred to as a liquid injection and impregnation process). When the height of the electrolyte solution from the bottom surface of the electrode assembly housed in the exterior housing is at least (¼) × H1 and not more than (¾) × H1, where H1 is the longitudinal dimension of the electrode assembly housed in the exterior housing, the longitudinal direction of the exterior housing is changed from vertical to horizontal. According to the battery manufacturing method of the present disclosure, the time required for impregnating the electrode assembly with the electrolyte can be shortened.

[0010] (battery) FIG. 1 is a perspective view showing an example of a nonaqueous electrolyte secondary battery (hereinafter also referred to as a battery) according to this embodiment. The battery 100 shown in FIG. 1 can be used for any purpose. For example, the battery 100 may be used as a main power source or a power source for power assist in an electric vehicle. A plurality of batteries 100 may be connected to form a battery module or a battery pack. The battery 100 may be a lithium-ion battery.

[0011] As shown in FIG. 1 , the battery 100 has an exterior body 110 (exterior can), an electrode terminal 120, and an inlet hole 130. The exterior body 110 has a rectangular shape. The rectangular shape is one example. The exterior body 110 may be cylindrical or pouch-shaped. The battery 100 is a rectangular secondary battery cell. The exterior body 110 may be made of, for example, an aluminum (Al) alloy. The exterior body 110 has a rectangular parallelepiped shape and forms the external appearance of the battery 100. The electrode terminal 120 and the inlet hole 130 may be formed on the exterior body 110.

[0012] The exterior body 110 has a fourth side wall 114, a third side wall 113 facing the fourth side wall 114, a pair of first side walls 111 standing upright from the edge of the fourth side wall 114 and facing each other, and a pair of second side walls 112 standing upright from the edge of the fourth side wall 114 and facing each other, connecting the first side walls 111 to each other. The electrode terminal 120 is arranged on the third side wall 113 and the fourth side wall 114. The electrode terminal 120 may be formed only on the third side wall 113 side, for example. The liquid inlet 130 may be arranged on the side wall of the exterior body 110 facing the electrode terminal 120, or on one of the side walls facing each other in the longitudinal direction of the exterior body 110. The liquid inlet 130 is arranged on the third side wall 113.

[0013] The third side wall 113 has a plane perpendicular to the Z-axis direction (third direction) that is perpendicular to the Y-axis direction and the X-axis direction. An electrode terminal 120 is arranged on each of the third side wall 113 and the fourth side wall 114. The fourth side wall 114 faces the third side wall 113 along the Z-axis direction. The liquid injection hole 130 may be provided in the third side wall 113.

[0014] The first side wall 111 has a plane perpendicular to the Y-axis direction. The plane of the first side wall 111 may have the largest area among the multiple planes of the exterior body 110. The first side wall 111 has a rectangular shape in a plan view (the shape when viewed in the Y-axis direction). When viewed in the Y-axis direction, the first side wall 111 has a rectangular shape with the Z-axis direction as the longitudinal direction and the X-axis direction as the lateral direction. In this specification, the longitudinal direction of the exterior body is the direction of the long sides of the plane of the first side wall 111, and the lateral direction of the exterior body is the direction of the short sides of the plane of the first side wall 111. When the exterior body 110 has a polygonal shape, the second side wall 112, the third side wall 113, and the fourth side wall 114 may all have a rectangular shape in a plan view, for example, a rectangle.

[0015] When the dimension in the longitudinal direction of the exterior body 110 (the dimension from the fourth side wall 114 to the third side wall 113) is H, the dimension H is 200 mm or more. The dimension H may be, for example, 2000 mm or less. According to the manufacturing method of the present disclosure, when the dimension H is within the above range, even if the battery is a large cell, for example, the time required to impregnate the electrode assembly with the electrolyte can be shortened, thereby shortening the time required to manufacture the battery. The dimension H can be the length of the long side of the plane having the largest area among the multiple planes that the exterior body 110 has.

[0016] When the dimension of exterior body 110 in the short direction (the dimension in the direction in which the pair of second side walls 112 face each other) is defined as W, dimension W may be, for example, 50 mm or more and 500 mm or less. Dimension W may be the length of the short side of the plane having the largest area among the multiple planes that exterior body 110 has.

[0017] When the width dimension in the direction in which the pair of first side walls 111 face each other is defined as T, dimension T may be, for example, 20 mm or more and 500 mm or less. Dimension T may be the dimension in the thickness direction (stacking direction) of the electrode body.

[0018] The ratio (W / H) of the dimension in the short direction (dimension W) to the dimension in the long direction (dimension H) of exterior body 110 may be, for example, 0.4 or less, for example, 0.3 or less, or 0.1 or more.

[0019] Fig. 2 is a schematic cross-sectional view of a battery. As shown in Fig. 2, in a battery 100, an exterior body 110 contains an electrode assembly 140, a current collecting member 150, and an electrolyte (not shown). The current collecting member 150 is connected to an electrode terminal 120. The electrode assembly is connected to the electrode terminal 120 by the current collecting member 150.

[0020] The electrode assembly 140 may include a positive electrode plate, a negative electrode plate, and a separator. In the electrode assembly 140, the active material layer of the positive electrode plate and the negative electrode active material layer of the negative electrode plate face each other with the separator interposed therebetween. The electrode assembly 140 may be, for example, a laminated type. The electrode assembly 140 may be formed, for example, by alternately stacking positive electrode plates and negative electrode plates with a separator sandwiched between them. The electrode assembly 140 may be formed, for example, by folding a strip-shaped separator zigzag, with positive electrode plates and negative electrode plates alternately arranged each time the separator is folded. The electrode assembly 140 may be, for example, a wound type. The positive electrode plate, negative electrode plate, and separator may all be, for example, strip-shaped. The electrode assembly 140 may be formed, for example, by stacking positive electrode plates, separators, and negative electrode plates in this order to form a laminate, and then winding the laminate into a spiral shape. The wound electrode body 140 may be formed into a flat shape after being wound.

[0021] The electrode assembly 140 may have a rectangular planar shape when viewed in the thickness direction (stacking direction). The electrode assembly 140 may have, for example, a rectangular parallelepiped outer shape. The electrode assembly 140 may have, for example, a flat rectangular parallelepiped shape.

[0022] When the electrode assembly 140 has a rectangular planar shape when viewed in the thickness direction, the long side direction is the longitudinal direction of the electrode assembly 140, which is also the longitudinal direction of the exterior housing 110. When the dimension of the electrode assembly 140 in the longitudinal direction of the exterior housing 110 (the dimension of the long side) is H1, dimension H1 may be, for example, 150 mm or more and 1900 mm or less. The dimension of the short side of the rectangle may be, for example, 50 mm or more and 1500 mm or less. When the electrode assembly 140 has a rectangular shape when viewed in the thickness direction, the ratio of the length of the short side to the long side may be, for example, 0.4 or less, for example, 0.3 or less, or 0.1 or more. The thickness of the electrode assembly 140 may be, for example, 5 mm or more and 50 mm or less.

[0023] The positive electrode plate has a positive electrode current collector and a positive electrode active material layer containing a positive electrode active material, with the positive electrode active material layer being formed on one or both sides of the positive electrode current collector. The positive electrode current collector is a metal foil made of an Al material such as Al or an Al alloy, and any metal foil that is stable within the potential range of the positive electrode plate may be used.

[0024] The positive electrode active material layer can be formed, for example, by applying a positive electrode mixture slurry onto a positive electrode current collector, drying it, and compressing it. The positive electrode mixture slurry can be prepared by adding a solvent such as N-methyl-2-pyrrolidone (NMP) to materials that form the active material layer, such as a positive electrode active material, a binder, and a conductive material, and kneading the mixture.

[0025] The positive electrode active material layer may contain, in addition to the positive electrode active material, a binder, a conductive material, and the like. Examples of binders include known materials such as fluororesins such as polyvinylidene fluoride (PVdF) and polytetrafluoroethylene (PTFE), and cellulose-based resins such as carboxymethyl cellulose (CMC). Examples of conductive materials include carbon materials. Examples of carbon materials include one or more selected from the group consisting of fibrous carbon, carbon black, coke, and activated carbon. Examples of fibrous carbon include carbon nanotubes (CNTs).

[0026] The positive electrode active material layer may have a thickness of, for example, 10 μm to 200 μm. The positive electrode active material layer may have a high density. The density of the positive electrode active material layer may be, for example, 3.5 g / cm. 3 or more, for example, 4.0 g / cm 3 It may have the following densities:

[0027] A negative electrode plate typically includes a negative electrode current collector and a negative electrode active material layer formed on one or both sides of the negative electrode current collector. The negative electrode current collector is a metal foil made of a copper material such as copper or a copper alloy. The negative electrode active material layer contains a negative electrode active material and may further contain a conductive material, a binder, and the like.

[0028] Examples of the negative electrode active material include known materials, such as carbon-based active material particles such as graphite, and metal-based active material particles containing an element selected from the group consisting of Si, Sn, Sb, Bi, Ti, and Ge. Examples of the conductive material include those described above. Examples of the binder include cellulose-based resins such as CMC, methyl cellulose (MC), and hydroxypropyl cellulose; polyacrylic acid; and styrene-butadiene rubber (SBR). CMC can also be used as a thickener.

[0029] The separator may have a substrate with a single-layer or multi-layer structure and a functional layer on at least one side of the substrate. The substrate may be a film made of a resin such as a polyolefin (e.g., polyethylene or polypropylene), polyester, cellulose, or polyamide, or a porous sheet such as a nonwoven fabric. The functional layer may be, for example, an adhesive layer and / or a heat-resistant layer. The adhesive layer may be formed, for example, with an adhesive. The heat-resistant layer may contain, for example, a filler and a binder.

[0030] The electrolytic solution is preferably a solution containing an electrolyte in a non-aqueous solvent such as an organic solvent. Examples of the electrolyte include one or more of LiPF6, LiBF4, LiClO4, LiFSO3, and LiBOB. Examples of the non-aqueous solvent include one or more of ethylene carbonate (EC), ethyl methyl carbonate (EMC), dimethyl carbonate (DMC), propylene carbonate (PC), butylene carbonate (BC), and diethyl carbonate (DEC). The electrolytic solution may further contain additives such as vinylene carbonate (VC), vinyl ethylene carbonate (VEC), and fluoroethylene carbonate.

[0031] (Storage process) In the storing step, the electrode body 140 is stored in the exterior body 110. The current collecting member 150 of the electrode body 140 can be connected to the electrode terminal 120. After storing the electrode body 140 inside the exterior body 110 from which the third side wall 113 has been removed, the third side wall 113 can be welded to the first side wall 111 and the second side wall 112.

[0032] (Liquid impregnation process) An electrolyte solution is injected into the exterior body 110 housing the electrode assembly 140 through the injection hole 130, thereby impregnating the electrode assembly 140 with the electrolyte solution. The injection and impregnation step will be described with reference to FIG. 3. First, the exterior body is arranged so that its longitudinal direction is vertical. In this specification, vertical orientation refers to a vertical direction, which does not have to be completely vertical and also includes a direction tilted within a range of approximately -10° to +10° from the vertical direction. The vertical orientation is preferably a vertical direction or a nearly vertical direction (a direction tilted from the vertical direction by several degrees), and more preferably a vertical direction. The horizontal orientation refers to a horizontal direction, which does not have to be completely horizontal and also includes a direction tilted within a range of approximately -10° to +10° from the horizontal direction. The horizontal orientation is preferably a horizontal direction or a nearly horizontal direction (a direction tilted from the horizontal direction by several degrees), and more preferably a horizontal direction. When the exterior body 110 is arranged so that the longitudinal direction of the exterior body 110 is vertical, the exterior body 110 is arranged so that the third side wall 113 in which the liquid injection hole 130 is located is on the upper side and the fourth side wall 114 is on the lower side.

[0033] Before injecting the electrolyte, the pressure inside the cell is reduced (a). The reduced pressure may be, for example, less than 0 kPa, and may be -50 kPa or less or -90 kPa or less. Next, the electrolyte is injected into the cell through the injection hole using a pressure difference (b). The amount of electrolyte injected can be adjusted depending on the size of the exterior body and the electrode body. After injection is complete, the electrolyte is impregnated at normal pressure while checking the electrolyte level (c). The electrolyte level is detected by the amount of X-ray transmission when irradiated from the short side of the cell. As shown in Figure 4, the amount of X-ray transmission is high in areas where electrolyte is not present and low in areas where electrolyte is present, so the boundary where the amount of X-ray transmission changes can be detected as the electrolyte level. Thereafter, as the impregnation of the electrode assembly 140 with the electrolyte progresses, when the liquid level of the electrolyte reaches a position where the height from the bottom surface of the electrode assembly 140 housed in the exterior housing 110 is equal to or greater than (¼)×H1 and equal to or less than (¾)×H1, the longitudinal orientation of the exterior housing 110 is changed from vertical to horizontal, and the electrode assembly 140 is impregnated with the electrolyte at normal pressure (d). As shown in FIG. 5, H1 is the longitudinal dimension of the electrode assembly 140, which is the dimension from the bottom surface 141 of the electrode assembly 140 housed in the exterior housing to the top surface 142 when the bottom surface 141 is set as the reference (0 mm). (¼)×H1 is the position where the distance from the bottom surface 141 is ¼ of the longitudinal dimension H1 of the electrode assembly 140. (¾)×H1 is the position where the distance from the bottom surface 141 is ¾ of the longitudinal dimension H1 of the electrode assembly 140. When the longitudinal orientation of the outer casing 110 is changed from vertical to horizontal, the liquid level of the electrolyte is preferably at a position where the height from the lower end surface 141 of the electrode body 140 housed in the outer casing 110 is (1 / 2) × H1.

[0034] The above-described liquid injection impregnation process can shorten the time required for the electrode assembly 140 to be impregnated with the electrolyte. The cases where the longitudinal orientation of the exterior body is not changed from vertical to horizontal and where the longitudinal orientation of the exterior body is changed from vertical to horizontal will be described with reference to FIGS. 6 and 7. FIG. 6 shows a cross section of the exterior body when the longitudinal orientation of the exterior body is not changed from vertical to horizontal. FIG. 7 shows a cross section of the exterior body when the longitudinal orientation of the exterior body is changed from vertical to horizontal. In FIGS. 6 and 7, the contact area between the exposed portion of the electrode assembly and the electrolyte is indicated by a thick line. As shown in FIG. 6, as the impregnation of the electrode assembly 140 with the electrolyte progresses, the liquid level drops, the contact area between the exposed portion of the electrode assembly and the electrolyte decreases, and the impregnation speed slows. On the other hand, as shown in Figure 7, when the height from the bottom end surface of the electrode body stored in the outer casing is at a position between (1 / 4) × H1 and (3 / 4) × H1, by changing the longitudinal orientation of the outer casing from vertical to horizontal, the reduction in the contact area between the exposed portion of the electrode body and the electrolyte can be reduced compared to when the longitudinal orientation of the outer casing is not changed from vertical to horizontal, and the time required for the electrolyte to be impregnated into the electrode body can be made shorter.

[0035] After the longitudinal orientation of the exterior body is changed from vertical to horizontal, the electrode body is impregnated with the electrolyte for a predetermined time. The liquid injection impregnation process is completed when there are no more portions of the electrode body that are not impregnated with the electrolyte (also referred to as unimpregnated portions). The time it takes for the electrolyte to impregnate the electrode body after the longitudinal orientation of the exterior body is changed from vertical to horizontal can be measured, for example, by removing the electrode body from the exterior body and checking for the presence or absence of unimpregnated portions (f). After the impregnation of the electrode body with the electrolyte is complete, the liquid injection hole is sealed and the battery is fabricated.

[0036] According to the battery manufacturing method of the present disclosure, the time required for impregnating the electrode body with the electrolyte can be shortened, thereby shortening the time required for battery manufacturing. The battery manufacturing method of the present disclosure is suitable for manufacturing batteries with a long dimension in the longitudinal direction of the exterior body, such as wide cells or large cells.

[0037] The present disclosure will now be described in further detail with reference to examples. [Example]

[0038] Example 1 (Cell preparation) Positive and negative electrode plates were alternately stacked with separators between them, with the separators interposed between the positive and negative electrode plates, each rectangular in shape when viewed from above. Separators were further stacked on both sides of the stack to produce a stacked laminate. Current collectors were attached to each of the positive and negative electrode plates. The thickness of the laminate was 13 mm. Two of these laminates were stacked to produce an electrode body. The electrode body was rectangular in shape when viewed from above, and when housed in an outer casing, the dimension H1 in the longitudinal direction of the outer casing (the dimension of the long side when viewed from above) was 284 mm, and the dimension in the lateral direction (the dimension of the short side when viewed from above) was 88 mm. The thickness of the electrode body (the dimension in the stacking direction) was 26 mm. The produced electrode body was housed in an outer casing to produce a cell. The exterior body had a longitudinal dimension (longer side dimension in plan view) of 308 mm, a lateral dimension (short side dimension in plan view) of 90 mm, and a thickness (dimension in the direction perpendicular to the longitudinal and lateral directions) of 30 mm. The exterior body had a liquid injection hole at one of the opposing longitudinal ends.

[0039] (Electrolyte injection and impregnation) The cell was placed with the inlet facing upward so that the longitudinal direction of the exterior body was vertical, and the cell was depressurized at a pressure of -96 kPa or less for 30 seconds. Next, 290 g of electrolyte (salt: LiPF6) was injected into the cell through the inlet by differential pressure. After the injection was completed, the electrolyte level was monitored while the cell was impregnated at normal pressure. The electrolyte level was detected by the amount of X-ray transmission when irradiating the cell from the short side. When the electrolyte level reached a position at a height of (1 / 2) × H1 (142 mm) from the bottom end surface (excluding the current collector) of the electrode body housed in the exterior body (defined as 0 mm), the cell was reoriented so that the longitudinal direction of the exterior body was horizontal. The electrolyte was then impregnated at normal pressure. The entire electrode body was impregnated with the electrolyte, completing the nonaqueous electrolyte secondary battery. The cell was disassembled at regular intervals to check the state of impregnation of the electrolyte, and the time from the completion of injection until the entire electrode body was impregnated with the electrolyte (hereinafter referred to as impregnation time) was measured. The results are shown in Table 1.

[0040] <Example 2> A nonaqueous electrolyte secondary battery was fabricated in the same manner as in Example 1, except that the orientation of the cell was changed so that the longitudinal direction of the exterior body was changed from vertical to horizontal when the liquid level of the electrolyte reached a position where the height from the bottom end surface of the electrode assembly housed in the exterior body was (¼) × H1 (71 mm). The results are shown in Table 1.

[0041] Example 3 A nonaqueous electrolyte secondary battery was fabricated in the same manner as in Example 1, except that the orientation of the cell was changed so that the longitudinal direction of the exterior body was changed from vertical to horizontal when the liquid level of the electrolyte reached a position where the height from the bottom end surface of the electrode assembly housed in the exterior body was (3 / 4) × H1 (213 mm). The results are shown in Table 1.

[0042] <Comparative Example 1> A nonaqueous electrolyte secondary battery was fabricated in the same manner as in Example 1, except that the cell orientation was not changed so that the longitudinal direction of the exterior body was horizontal rather than vertical, and the impregnation with the electrolyte solution was carried out while maintaining the cell orientation in a state in which the longitudinal direction of the exterior body was vertical. The results are shown in Table 1.

[0043] <Comparative Example 2> A nonaqueous electrolyte secondary battery was fabricated in the same manner as in Example 1, except that the cell was placed so that the longitudinal direction of the exterior body was oriented horizontally, the electrolyte solution was poured into the cell, and the impregnation of the electrolyte solution was carried out while maintaining the cell orientation in such a state that the longitudinal direction of the exterior body was oriented horizontally. The results are shown in Table 1.

[0044] <Comparative Example 3> A nonaqueous electrolyte secondary battery was fabricated in the same manner as in Example 1, except that the orientation of the cell was changed so that the longitudinal direction of the exterior body was changed from vertical to horizontal when the liquid level of the electrolyte solution reached a position 50 mm [<(1 / 4) × H1] above the bottom end surface of the electrode assembly housed in the exterior body. The results are shown in Table 1.

[0045] <Comparative Example 4> A nonaqueous electrolyte secondary battery was fabricated in the same manner as in Example 1, except that the orientation of the cell was changed so that the longitudinal direction of the exterior body was changed from vertical to horizontal when the liquid level of the electrolyte reached a position 234 mm [>(3 / 4) × H1] above the bottom surface of the electrode assembly housed in the exterior body. The results are shown in Table 1.

[0046] [Table 1]

[0047] In Examples 1 to 3, the time required for impregnating the electrode body with the electrolyte solution was shorter than in Comparative Examples 1 to 4. This shows that the method for manufacturing a nonaqueous electrolyte secondary battery according to the present disclosure can shorten the manufacturing time for a nonaqueous electrolyte secondary battery. [Explanation of symbols]

[0048] 100 Battery, 110 Exterior body, 111 First side wall, 112 Second side wall, 113 Third side wall, 114 Fourth side wall, 120 Electrode terminal, 130 Inlet hole, 140 Electrode body, 141 Lower end surface, 142 Upper end surface, 150 Current collecting member.

Claims

1. A method for manufacturing a nonaqueous electrolyte secondary battery including an exterior body, and an electrolytic solution and an electrode assembly within the exterior body, comprising: The longitudinal dimension of the exterior body is 200 mm or more, a step of housing an electrode assembly in the exterior housing; a step of placing the exterior body so that the longitudinal direction of the exterior body is oriented vertically, injecting the electrolyte into the exterior body, and impregnating the electrode body with the electrolyte; and then changing the orientation of the exterior body so that the longitudinal direction of the exterior body is oriented horizontally from the vertical direction, and impregnating the electrode body with the electrolyte; Including, a method for manufacturing a nonaqueous electrolyte secondary battery, wherein, when the height of the liquid surface of the electrolyte solution from a lower end surface of the electrode body housed in the exterior body is equal to or greater than (¼)×H1 and equal to or less than (¾)×H1, the longitudinal orientation of the exterior body is changed from a vertical orientation to a horizontal orientation, where H1 is the dimension of the electrode body in the longitudinal direction of the exterior body.

2. The method for manufacturing a nonaqueous electrolyte secondary battery according to claim 1 , wherein an inlet hole is disposed in a side wall of the exterior body on the electrode terminal side.

3. The method for manufacturing a nonaqueous electrolyte secondary battery according to claim 1 , wherein a liquid injection hole is disposed in one of the side walls opposing each other in the longitudinal direction of the exterior body.

4. 2. The method for manufacturing a nonaqueous electrolyte secondary battery according to claim 1, wherein the ratio of the dimension in the short direction to the dimension in the long direction of the exterior body is 0.4 or less.

5. The method for manufacturing a nonaqueous electrolyte secondary battery according to claim 1 , wherein the longitudinal dimension of the exterior body exceeds 200 mm, and the longitudinal dimension of the electrode body of the exterior body is 200 mm or more.

6. The method for producing a nonaqueous electrolyte secondary battery according to claim 1 , wherein the electrode assembly is a laminated type or a wound type.

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