Manufacturing method of stacked battery and stacked battery

Abstract

To provide a laminated battery manufacturing method with which it is possible to manufacture a laminated battery having high structural reliability.SOLUTION: Provided is a laminated battery manufacturing method comprising: an arrangement step for arranging a plastic liquid injection frame 20 having a liquid injection opening P on a side surface of an electrode laminate 10; a liquid injection step for injecting an electrolyte to the inside of the electrode laminate; a first sealing step for locating a first member 30 having a resin layer A on a surface of the liquid injection frame, in which an x-axis direction orthogonal to a z-axis direction is taken as a normal direction, and sealing the liquid injection opening; a battery processing step for applying charging and / or aging after the first sealing step; an open hole forming step for forming an open hole Q that communicates with the liquid injection opening in the first member after the battery processing step; and a second sealing step, by using a second member 40 having a resin layer B and a metal layer, for locating the resin layer B of the second member on a surface of the first member, in which the x-axis direction is taken as the normal direction, and thereby covering the open hole and sealing the liquid injection opening.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a method for manufacturing a stacked battery and the stacked battery. [Background technology]

[0002] There is a known technology for sealing the periphery of an electrode laminate having a plurality of electrodes with a resin body. For example, Patent Document 1 discloses a bipolar battery having at least one combination of a positive electrode and a negative electrode connected in series and a detection tab, characterized in that the exterior of the battery element is covered with at least one resin group.

[0003] Furthermore, Patent Document 2 discloses a method for manufacturing a secondary battery, which is characterized in that the charging step, degassing step, and aging step are carried out in a restrained state in which a pair of wide surfaces of a battery case are clamped from both sides and the battery case is pressed in the clamping direction.

[0004] Patent Document 3 discloses a method for manufacturing an energy storage device, which includes a step of filling the space between a stack in which a frame body is joined to the peripheral edge of each electrode plate of a plurality of bipolar electrodes and a nest held by a nest holding portion between adjacent frame bodies in the stacking direction, with resin, with a nest having one end extending into the frame and the other end held by the nest holding portion outside the frame. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2005-005163 A [Patent Document 2] JP 2010-021104 A [Patent Document 3] JP 2019-016459 A Summary of the Invention [Problem to be solved by the invention]

[0006] When manufacturing a stacked battery having an electrode stack in which multiple electrodes are stacked in the z-axis direction (thickness direction), an electrolyte is injected into the internal space of each generating unit. In this case, due to design constraints, a resin-made electrolyte injection frame having multiple injection ports for supplying electrolyte to each internal space may be arranged along the side of the electrode stack. After the electrolyte is injected, the electrolyte injection port of the electrolyte injection frame needs to be sealed. Here, it is considered that a barrier property can be obtained by arranging a sealing member having a metal layer on the electrolyte injection port and welding and sealing it, and thus the intrusion of moisture and the like into the battery can be suppressed. However, during battery treatment such as charging treatment and aging treatment after this sealing, the internal pressure of the electrode stack increases, the electrolyte injection frame having the electrolyte injection port is damaged, and electrolyte leakage or the like occurs, which may reduce structural reliability.

[0007] The present disclosure has been made in consideration of the above-described circumstances, and has a primary object to provide a method for manufacturing a stacked battery that can produce a stacked battery with high structural reliability. [Means for solving the problem]

[0008] [1] a preparation step of preparing an electrode stack including a plurality of electrodes stacked in the z-axis direction; a placement step of placing a resin liquid pouring frame having a liquid pouring port on a side surface of the electrode stack; a liquid injection step of injecting an electrolyte solution into the electrode stack from the liquid injection port of the liquid injection frame; a first sealing step of sealing the liquid pouring port by disposing a first member having a resin layer A on a surface of the liquid pouring frame whose normal direction is the x-axis direction perpendicular to the z-axis direction after the liquid pouring step; a battery treatment step of performing at least one of charging and aging after the first sealing step; a through-hole forming step of forming a through-hole in the first member, the through-hole communicating with the liquid injection port, after the battery processing step; a second sealing step of using a second member having a resin layer B and a metal layer and disposing the resin layer B of the second member on a surface of the first member whose normal direction is the x-axis direction, thereby covering the through hole and sealing the liquid injection hole.

[0009] [2] The method for manufacturing a stacked battery according to [1], wherein the first member and the second member are in the form of a film.

[0010] [3] The method for producing a laminated battery according to [1] or [2], wherein the first member has a plurality of resin layers as the resin layer A.

[0011] [4] The method for manufacturing a laminated battery according to any one of [1] to [3], wherein the second member has a resin layer C on the opposite side of the metal layer to the resin layer B.

[0012] [5] The method for manufacturing a laminated battery according to any one of [1] to [4], wherein the electrode laminate includes a bipolar electrode having a current collector, a positive electrode layer disposed on one surface of the current collector, and a negative electrode layer disposed on the other surface of the current collector.

[0013] [6] an electrode stack including a plurality of electrodes stacked in the z-axis direction; a resin liquid injection frame disposed on a side surface of the electrode stack and having a liquid injection port for supplying an electrolyte solution into the electrode stack; a first member arranged on a surface of the liquid injection frame opposite to the electrode stack, the surface having a normal direction in an x-axis direction perpendicular to the z-axis direction; a second member disposed on a surface of the first member opposite to the liquid injection frame, the surface having a normal direction in the x-axis direction; the first member has a resin layer A, and has a through hole that covers the liquid injection hole and communicates with the liquid injection hole, the second member has, in order from the first member side, a resin layer B and a metal layer, and covers the through hole and seals the liquid injection hole, in this stacked battery.

[0014] [7] The stacked battery according to [6], wherein the first member and the second member are in the form of a film.

[0015] [8] The laminated battery according to [6] or [7], wherein the first member has a plurality of resin layers as the resin layer A.

[0016] [9] The laminated battery according to any one of [6] to [8], wherein the second member has a resin layer C on the opposite side of the metal layer to the resin layer B.

[0017]

[10] The laminated battery according to any one of [6] to [9], wherein the electrode laminate includes a bipolar electrode having a current collector, a positive electrode layer disposed on one surface of the current collector, and a negative electrode layer disposed on the other surface of the current collector. Effect of the Invention

[0018] The manufacturing method of a stacked battery according to the present disclosure has the effect of manufacturing a stacked battery with high structural reliability. [Brief description of the drawings]

[0019] [Figure 1] 1A to 1C are schematic cross-sectional views illustrating a method for manufacturing a stacked battery in the present disclosure. [Diagram 2] 1 is a schematic cross-sectional view illustrating an electrode stack according to the present disclosure. [Diagram 3] FIG. 2 is a schematic perspective view illustrating a liquid filling frame according to the present disclosure. [Figure 4] 1 is a schematic cross-sectional view illustrating an electrode stack in which a liquid injection frame according to the present disclosure is disposed. [Diagram 5] 1 is a schematic cross-sectional view illustrating a temporary sealing laminate according to the present disclosure. [Figure 6] 4 is a schematic cross-sectional view illustrating an electrode stack preparation step in a manufacturing method for a stacked battery in the present disclosure. FIG. [Figure 7] 4 is a schematic cross-sectional view illustrating a liquid pouring frame arrangement step in a manufacturing method for a stacked battery according to the present disclosure. FIG. [Figure 8] 4 is a schematic cross-sectional view illustrating a liquid pouring frame arrangement step in a manufacturing method for a stacked battery according to the present disclosure. FIG. [Figure 9] 1 is a schematic cross-sectional view illustrating a stacked battery in which a liquid filling frame is directly welded and sealed with a sealing member having a metal layer. [Figure 10] FIG. 1 is a schematic cross-sectional view illustrating a stacked battery according to the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Hereinafter, the embodiments of the present disclosure will be described in detail with reference to the drawings. Each of the drawings shown below is a schematic illustration, and the size and shape of each part are appropriately exaggerated to facilitate understanding. In addition, in this specification, when expressing an aspect in which another member is arranged relative to a certain member, the term "above" or "below" is used, unless otherwise specified, it includes both a case in which another member is arranged directly above or below a certain member so as to be in contact with the certain member, and a case in which another member is arranged above or below a certain member via another member.

[0021] A. Manufacturing method of stacked battery FIG. 1 is a schematic cross-sectional view illustrating a method for manufacturing a stacked battery according to the present disclosure. First, as shown in FIG. 1(a), an electrode stack including a plurality of electrodes E stacked in the z-axis direction is prepared (preparation step). As shown in FIG. 1(a), a communication hole O leading to the inside of the electrode stack 10 is usually formed on the side surface SS of the electrode stack 10. Next, as shown in FIG. 1(b), a resin-made liquid pouring frame 20 having a plurality of liquid pouring ports P for pouring an electrolyte solution into the inside of the electrode stack 10 is arranged on the side surface SS of the electrode stack 10 (arrangement step). Next, an electrolyte solution (not shown) is poured into the inside of the electrode stack from the liquid pouring ports P of the liquid pouring frame 20 (liquid pouring step). 1(c), after the liquid pouring step, a first member 30 having a resin layer A (resin layer 31) is disposed on a surface 20S of the liquid pouring frame 20 opposite the electrode stack 10, the surface 20S having a normal direction in the x-axis direction perpendicular to the z-axis direction, to seal the liquid pouring port P of the liquid pouring frame 20 (first sealing step). As a result, a temporarily sealed stack 50 is obtained.

[0022] After the first sealing step, as shown in FIG. 1(d), at least one of charging and aging is performed on the temporary sealed laminate 50 (battery treatment step). At this time, gas is generated inside the electrode laminate 10, and the internal pressure of the temporary sealed laminate 50 increases. After the battery treatment step, as shown in FIG. 1(e), a through hole Q communicating with the liquid injection port P is formed in the first member 30 (through hole forming step). This releases the sealed state of the temporary sealed laminate 50, and the increased internal pressure decreases. After the through hole forming step, as shown in FIG. 1(f), a second member 40 having a resin layer B (resin layer 41) and a metal layer 42 is used, and the resin layer B (resin layer 41) of the second member 40 is disposed on the surface 30S of the first member 30 opposite to the liquid injection frame 20, with the x-axis direction as the normal direction, to cover the through hole Q and seal the liquid injection port P (second sealing step). This results in a laminated battery 100.

[0023] As described above, it is believed that the intrusion of moisture and the like into the battery can be suppressed by sealing the inlet of the inlet of the inlet frame with a sealing member having a metal layer. In particular, in the case of a large battery, even a small amount of moisture can lead to deterioration of the entire battery, so it is preferable that the sealing member has high barrier properties. However, when the sealed body is subjected to at least one of battery treatments, ie, charging and aging, gas is generated inside the electrode stack, the internal pressure of the sealed body increases, and the inlet frame may be damaged. This may result in leakage of the electrolyte, etc., and a decrease in structural reliability.

[0024] According to the present disclosure, after the battery processing step (FIG. 1(d)), a through hole forming step (FIG. 1(e)) is performed to provide a through hole Q in the first member 30, thereby releasing the sealed state of the temporarily sealed laminate 50 and reducing the increased internal pressure. Thereafter, the through hole Q of the first member 30 is covered with the second member 40 while the filling port P of the filling frame 20 is sealed (FIG. 1(f)), thereby obtaining a laminated battery in which deterioration of structural reliability is suppressed.

[0025] Furthermore, according to the present disclosure, a stacked battery capable of suppressing peeling between the first member and the second member can be manufactured. Specifically, when the through hole Q of the first member 30 is covered with the second member 40 in the second sealing step (FIG. 1(f)), gas may be present between the first member 30 and the second member 40, but the gas can be released by the through hole Q formed in the first member 30. If gas is present, peeling will occur between the first member and the second member when exposed to high temperatures in the field.

[0026] Furthermore, according to the present disclosure, a stacked battery capable of suppressing short circuiting can be manufactured. FIG. 9 shows a schematic cross-sectional view of a stacked battery in which the filling port of the filling frame is directly sealed with a sealing member having a metal layer. Here, the sealing member 40 generally has a resin layer B (resin layer 41) and a metal layer 42. In this case, if the welding sealing conditions are excessive, the resin contained in the resin layer B (resin layer 41) may melt and flow, and the metal layer 42 may be exposed. If the exposed metal layer 42 (within the dotted line frame) directly contacts an electrolyte having a different potential, a short circuit may occur. In particular, when welding sealing is performed under reduced pressure, the pressure inside the battery becomes negative pressure, so that the welding sealing conditions may become excessive in order to ensure welding strength. On the other hand, according to the present disclosure, as shown in FIG. 1, by disposing the first member 30 between the filling frame 20 and the second member 40, even if a sealing member having a metal layer is used as the second member 40 and the metal layer 42 is exposed, there is a distance to the adjacent filling port, so that a short circuit can be suppressed.

[0027] Furthermore, according to the present disclosure, since the through hole is formed in the first member, the welding and sealing conditions in the second sealing step can be relaxed.

[0028] 1. Preparation process This step is a step of preparing an electrode laminate including a plurality of electrodes stacked in the z-axis direction ( FIG. 1(a)). FIG. 2 is a schematic cross-sectional view illustrating an electrode laminate in the present disclosure. As shown in FIG. 2, an electrode laminate 10 includes a plurality of electrodes E stacked in the z-axis direction. The electrode has a current collector and an electrode layer (positive electrode layer or negative electrode layer) disposed on at least one surface of the current collector.

[0029] 2, the electrode laminate 10 may have, as an electrode E, a bipolar electrode BP having a current collector 1, a positive electrode layer 2 arranged on one surface of the current collector 1, and a negative electrode layer 3 arranged on the other surface of the current collector 1. The electrode laminate in the present disclosure may have only one bipolar electrode BP, or may have two or more bipolar electrodes BP. On the other hand, the electrode laminate in the present disclosure is not particularly limited as long as it includes a plurality of electrodes E stacked in the z-axis direction, and may not have a bipolar electrode.

[0030] The electrode stack in the present disclosure may include a plurality of bipolar electrodes in the z-axis direction, and a separator may be disposed between each of the plurality of bipolar electrodes adjacent to each other.

[0031] The electrode laminate 10 shown in FIG. 2 has a bipolar electrode BP1, a bipolar electrode BP2, a positive electrode end electrode CA, and a negative electrode end electrode AN as electrodes E. The bipolar electrode BP1 has a positive electrode layer 2a arranged on one surface of the current collector 1a and a negative electrode layer 3a arranged on the other surface of the current collector 1a. The bipolar electrode BP2 has a positive electrode layer 2b arranged on one surface of the current collector 1b and a negative electrode layer 3b arranged on the other surface of the current collector 1b. The positive electrode end electrode CA has a current collector 1 and a positive electrode layer 2 arranged on one surface of the current collector 1. The negative electrode end electrode AN has a current collector 1 and a negative electrode layer 3 arranged on one surface of the current collector 1.

[0032] As shown in FIG. 2, the electrode laminate 10 may have a plurality of generating units U (U1, U2, U3) stacked in the z-axis direction. The generating unit U has a positive electrode layer 2, a negative electrode layer 3, and a separator 4 disposed between the positive electrode layer 2 and the negative electrode layer 3. As shown in FIG. 2, the generating units U (U1, U2, U3) may be directly connected to each other. Although not shown in particular, the generating units may be connected in parallel to each other. The generating units are independent of each other so that the electrolyte does not flow between them. In FIG. 2, the generating units U (U1, U2, U3) are independent of each other so that the electrolyte does not flow between them. The generating units U (U1, U2, U3) each have an internal space V (V1, V2, V3). For example, the generating unit U1 and the generating unit U2 are partitioned by a current collector 1 and a resin member 5 and are independent of each other.

[0033] One generating unit may be constructed using two bipolar electrodes. In FIG. 2, the electrode stack 10 has a bipolar electrode BP1 and a bipolar electrode BP2 in the z-axis direction. A separator 4 is disposed between the adjacent bipolar electrodes BP1 and BP2. The generating unit U2 is constructed from a positive electrode layer 2 in the bipolar electrode BP2, a negative electrode layer 3 in the bipolar electrode BP1, and a separator 4 disposed therebetween. On the other hand, the generating unit U1 is constructed from a positive electrode layer 2 in the bipolar electrode BP1, a negative electrode layer 3 in the negative electrode end electrode AN, and a separator 4 disposed therebetween. In addition, the generating unit U3 is constructed from a negative electrode layer 3 in the bipolar electrode BP2, a positive electrode layer 2 in the positive electrode end electrode CA, and a separator 4 disposed therebetween.

[0034] A communication hole is usually formed in each of the plurality of power generating units. As shown in Fig. 2, the communication hole O is formed, for example, so as to penetrate the resin member 5 in the x-axis direction perpendicular to the z-axis direction, and preferably communicates with the internal space V of the power generating unit U and a liquid pouring port P of the liquid pouring frame 20 described later.

[0035] The electrode laminate in the present disclosure may have a resin member arranged along the outer edge of a plurality of current collectors. For example, in FIG. 2, the resin member 5 is arranged along the outer edge of the current collector 1. When the electrode laminate 10 is viewed from the z-axis direction, the resin member 5 is a member that prevents leakage of the electrolyte, and is usually arranged around the entire outer edge of the current collector 1. Examples of the resin constituting the resin member include thermoplastic resins. Examples of the thermoplastic resin include olefin-based resins such as polyethylene and polypropylene. The resin member in the present disclosure usually has a communication hole O that communicates with the internal space V (V1, V2, V3) of the power generation unit U (U1, U2, U3) and the liquid injection port P of the liquid injection frame 20 described later, as shown in FIG. 2. It is preferable that the communication hole O extends in the x-axis direction and penetrates the resin member 5. In addition, the resin member 5 usually has a plurality of communication holes O.

[0036] The planar shape of the electrode laminate (shape seen from the z-axis direction) is not particularly limited, and examples thereof include quadrangles such as squares and rectangles. The length of one side in the planar shape of the electrode laminate is, for example, 30 cm or more, and may be 50 cm or more, or may be 100 cm or more. Meanwhile, the length of one side is, for example, 200 cm or less. Furthermore, when the planar shape of the electrode laminate is rectangular, it is preferable that the length of the short side is within the above range. Furthermore, in the rectangle, the length of the long side relative to the short side (aspect ratio) may be greater than 1.0 and may be 1.2 or more. Meanwhile, the aspect ratio is, for example, 3.0 or less.

[0037] The method for producing the electrode laminate is not particularly limited. FIG. 6 is a schematic cross-sectional view (exploded view) illustrating a method for producing the electrode laminate in the present disclosure. As shown in FIG. 6(a), a bipolar electrode BP1 and a bipolar electrode BP2 are prepared. The bipolar electrode BP1 has a positive electrode layer 2a arranged on one surface of a current collector 1a and a negative electrode layer 3a arranged on the other surface of the current collector 1a.

[0038] Furthermore, the bipolar electrode BP1 has a resin frame 51a arranged along the outer edge of the current collector 1a. When the bipolar electrode BP1 is viewed from the z-axis direction, the resin frame 51a is usually arranged along the entire outer edge of the current collector 1a. For example, when the outer edge of the current collector 1a has a rectangular shape, the resin frame 51a is arranged along the entire outer edge of the rectangle. As shown in FIG. 6, the resin frame 51a preferably covers a part of one main surface α of the current collector 1a, a part of the other main surface β of the current collector 1a, and the entire side surface γ constituting the outer edge of the current collector 1a.

[0039] As shown in Fig. 6(a), the bipolar electrode BP2 has a positive electrode layer 2b disposed on one surface of the current collector 1b and a negative electrode layer 3b disposed on the other surface of the current collector 1b. Furthermore, the bipolar electrode BP2 has a resin frame 51b disposed along the outer edge of the current collector 1b. The details of the bipolar electrode BP2 are the same as those of the bipolar electrode BP1 described above.

[0040] As shown in Fig. 6(a), the negative electrode layer 3a of the bipolar electrode BP1 and the positive electrode layer 2b of the bipolar electrode BP2 are opposed to each other with a separator 4 interposed therebetween. At this time, at least a part of the outer edge of the separator 4 is disposed between the resin frame 51a and the resin frame 51b. Also, as shown in Fig. 6(a), the insert 6 and the resin frame (spacer) 51c are disposed between the resin frame 51a of the bipolar electrode BP1 and the resin frame 51b of the bipolar electrode BP2.

[0041] As shown in FIG. 6(b), the bipolar electrode BP1, the bipolar electrode BP2, the separator 4, and the insert 6 are arranged, then the negative electrode member AN having the separator layer 4, the negative electrode layer 3, and the current collector 1 is arranged on the positive electrode layer 2a of the bipolar electrode BP1, and the positive electrode member CA having the separator layer 4, the positive electrode layer 2, and the current collector 1 is arranged on the negative electrode layer 3b of the bipolar electrode BP2. Then, the resin frames 51a, 51b, and 51c are welded. This forms a power generation unit having the positive electrode layer 2b, the negative electrode layer 3a, and the separator 4. In addition, the resin member 5 is formed by welding the resin frames 51a, 51b, and 51c. Furthermore, the insert 6 is arranged so as to penetrate the resin member 5. In this manner, an electrode stack with the insert inserted is obtained.

[0042] 2. Liquid filling frame placement process 1(b), this step is a step of arranging a resin liquid filling frame 20 having a liquid filling port P for supplying an electrolyte solution to the inside of the electrode stack on a side surface SS of the electrode stack 10. The liquid filling frame may be arranged by being formed on the side surface of the electrode stack by resin molding such as injection molding, or may be prepared as a separate member and arranged on the side surface of the electrode stack.

[0043] 2, the side surface SS of the electrode laminate 10 refers to a surface extending in the z-axis direction in the electrode laminate 10. The side surface of the electrode laminate is usually a surface connecting the top surface (one main surface) and the bottom surface (the other main surface) of the electrode laminate, which are opposed to each other in the z-axis direction.

[0044] As shown in Fig. 1(b), the liquid filling frame 20 preferably has a plurality of liquid filling ports P (P1, P2, P3) for supplying the electrolyte solution to the inside of the electrode stack 10. The liquid filling ports P1, P2, P3 are arranged corresponding to the power generation units U1, U2, U3, respectively. On the other hand, although not specifically shown, the liquid filling frame may have only one liquid filling port. The liquid filling port P is a portion capable of supplying the electrolyte solution in the x-axis direction perpendicular to the z-axis direction.

[0045] Fig. 3 is a schematic perspective view illustrating a liquid filling frame in the present disclosure. As shown in Fig. 1(b) and Fig. 3, the liquid filling frame 20 usually has a partition part 21 that divides each liquid filling port P. The partition part 21 is, for example, welded to a resin member 5. The liquid filling frame 20 shown in Fig. 3 has a plurality of liquid filling ports P in the z-axis direction and a plurality of liquid filling ports P in the y-axis direction. In addition, the partition part 21 has a plurality of vertical walls 21z and a plurality of horizontal walls 21y. Each liquid filling port P is divided by the vertical wall 21z and the horizontal wall 21y.

[0046] Examples of the resin constituting the liquid injection frame include thermoplastic resins. Examples of the thermoplastic resin include polyolefin resins such as polypropylene (PP) and polyethylene (PE), and polyethylene terephthalate. Among them, resins having resistance to the electrolyte used (electrolyte resistance) are preferable. In addition, resins having excellent mechanical strength and moldability are preferable. Examples of such resins include polyolefin resins such as polypropylene (PP) and polyethylene (PE). The liquid injection frame is disposed on a side surface of the electrode laminate. As shown in FIG. 1(b), the liquid injection frame 20 may be disposed on at least one side surface (a side surface having a communication hole O) of the electrode laminate 10.

[0047] Fig. 4 is a schematic cross-sectional view illustrating an electrode laminate in which a liquid injection frame according to the present disclosure is arranged. As shown in Fig. 4, the liquid injection frame 20 may have a base 22 in addition to a partition 21. The partition 21 extends from the base 22, for example. The base 22 is welded to a resin member 5, for example.

[0048] The thickness of the liquid injection frame 20 is, for example, 1 mm or more and 20 mm or less, or may be 4 mm or more and 15 mm or less. The thickness of the liquid injection frame is the thickness in the x-axis direction perpendicular to the z-axis direction (T 20 )

[0049] Fig. 7 is a schematic cross-sectional view (exploded view) illustrating a method for forming a liquid injection frame by injection molding in this step. As shown in Fig. 7(a), the electrode stack 10 in this step may have a insert 6 for forming a communication hole on a side surface SS. One end t1 of the insert 6 is located inside the electrode stack 10, and the other end t2 protrudes outward from the side surface SS of the electrode stack 10. The insert 6 is a part of a metal mold, and is attached to a mold 70 (mother die), and is a member for producing a resin molded product.

[0050] Next, as shown in FIG. 7(b), the electrode laminate 10, which is an insert product, is placed in the mold 70 so that the side surface SS of the electrode laminate 10 faces the surface of the mold 70 on which the recess 71 is formed. The recess 71 of the mold 70 is a portion into which the insert 6 is inserted. Next, as shown in FIG. 7(c), a resin is supplied between the electrode laminate 10 and the mold 70 to form a liquid injection frame (resin molded body) 20. Although not shown in FIG. 7(c), when the liquid injection frame 20 is formed, a mold is usually also placed above and below the electrode laminate 10. Next, as shown in FIG. 8(a), the mold 70 is removed from the electrode laminate 10. As a result, the liquid injection frame 20 including the partition wall portion 21 and the base portion 22 that divide the liquid injection ports P is obtained. Next, as shown in FIG. 8(b), when the insert 6 is removed from the electrode laminate 10, a communication hole O is formed in the resin member 5.

[0051] 3. Liquid injection process This step is a step of injecting an electrolyte into the electrode laminate from the injection port of the injection frame. The method of supplying the electrolyte is not particularly limited, and for example, a known method using an injection device is used. As shown in FIG. 1(b), the electrolyte is introduced into the injection port P and supplied into the electrode laminate through the communication hole O. As a result, the positive electrode layer, the negative electrode layer, and the separator are each impregnated with the electrolyte.

[0052] 4.First sealing process 1(c), this step is a step of sealing the liquid pouring port P of the liquid pouring frame 20 by arranging a first member 30 having a resin layer A (resin layer 31) on a surface 20S of the liquid pouring frame having a normal direction in the x-axis direction orthogonal to the z-axis direction after the liquid pouring step, thereby obtaining a temporarily sealed laminate 50. The "surface of the liquid pouring frame having a normal direction in the x-axis direction orthogonal to the z-axis direction" refers to the surface of the liquid pouring frame having an opening of the liquid pouring port P on the side opposite the electrode laminate.

[0053] As shown in FIG. 1(c), for example, by pressing a heat bar 60 heated to a predetermined temperature against the first member 30 from the side opposite to the liquid filling frame 20, the first member 30 and the liquid filling frame 20 are welded together, and the liquid filling port P of the liquid filling frame 20 is sealed with the first member 30. Note that the welding and sealing means is not limited to the above method, and can be performed by a general heating means. The first sealing step is preferably performed in a vacuumed chamber in a reduced pressure atmosphere. Also, in order to prevent the first member from adhering to the heat bar, the welding and sealing may be performed by sandwiching an adhesion-preventing member such as a PET film or glass cloth between the first member and the heat bar.

[0054] The first member has a resin layer A. The resin layer A may be a single resin layer, or may have multiple resin layers. FIG. 5 is a schematic cross-sectional view illustrating a temporary sealing laminate in the present disclosure in the case where the first member 30 has multiple resin layers as the resin layer A (resin layer 31). As shown in FIG. 5, the first member 30 may have a three-layer structure consisting of a first resin layer 31a, a second resin layer 31b, and a third resin layer 31c as the resin layer A (resin layer 31) from the liquid pouring frame 20 side. The first resin layer 31a and the third resin layer 31c each preferably contain a thermoplastic resin. When the first resin layer 31a contains a thermoplastic resin, welding between the liquid pouring frame 20 and the first member 30 becomes easy. Also, when the third resin layer 31c contains a thermoplastic resin, welding between the first member 30 and the second member 40 becomes easy. Furthermore, by providing the second resin layer 31b between the first resin layer 31a and the third resin layer 31c, the strength of the first member can be improved.

[0055] Examples of the thermoplastic resin contained in the first resin layer and the third resin layer include olefin resins. The olefin resin is a resin mainly composed of an olefin component unit, and examples thereof include polyolefins such as polyethylene and polypropylene, and acid-modified polyolefins such as acid-modified polyethylene and acid-modified polypropylene. The acid-modified polyolefin is a polyolefin to which an acid group has been introduced. The type of the acid group is not particularly limited, but a carboxylic acid anhydride residue (-CO-O-OC-) is preferable. The acid group may be introduced by any compound, and an example of a compound to introduce the acid group is maleic anhydride. In the present disclosure, among them, acid-modified polypropylene is preferable. This is because it has sufficient welding strength to the injection frame, can withstand an increase in internal pressure, and has high electrolyte resistance. In particular, acid-modified polypropylene modified by maleic anhydride is preferable. The thermoplastic resins contained in the first resin layer and the third resin layer may be the same type or different types.

[0056] The resin contained in the second resin layer is preferably a resin having high mechanical strength and excellent resistance to an increase in internal pressure during the battery processing process. Examples of such resins include polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate. Among them, polyethylene naphthalate is preferred.

[0057] The first member is preferably in the form of a film. In particular, it is preferably a resin film made of a single resin layer or a plurality of resin layers. When the first member is a resin film, the pouring hole of the pouring frame can be easily sealed.

[0058] The thickness of the first member is not particularly limited, but is preferably 100 μm or more, and more preferably 120 μm or more. On the other hand, it is preferably 200 μm or less, and more preferably 180 μm or less. The thickness of the first member is the thickness in the x-axis direction (T 30 When the first member is a laminate of multiple layers, the above thickness refers to the total thickness of the multiple layers included in the first member.

[0059] The welding and sealing conditions (heating temperature, pushing distance, time, etc.) in the first sealing step are not particularly limited. The heating temperature is preferably a temperature at which at least one of the resin contained in the liquid pouring frame 20 and the resin contained in the resin layer A of the first member (when the resin layer A has a plurality of resin layers, the first resin layer arranged on the liquid pouring frame side) is softened or melted. For example, the heating temperature is 80°C or higher and 200°C or lower, and may be 100°C or higher and 180°C or lower. The heating time is, for example, 10 seconds or higher and 60 seconds or lower, and may be 20 seconds or higher and 60 seconds or lower. The pushing distance is, for example, 0.2 mm or higher and 1.0 mm or lower, and may be 0.5 mm or higher and 0.8 mm or lower.

[0060] 5. Battery processing process This step is a battery treatment step in which at least one of charging and aging is performed after the first sealing step. As shown in Fig. 1(d), by performing at least one of battery treatments, i.e., charging and aging, on the temporary sealed laminate 50, the internal pressure of the temporary sealed laminate increases. The conditions for charging or aging are not particularly limited. The charging process can be performed, for example, in the same manner as in the case of performing initial charging in a general lithium ion battery. For example, charging may be performed until the SOC (State of Charge) becomes 50% or more, until the SOC becomes 70% or more, or until the SOC becomes 90% or more. The aging process may be, for example, a high-temperature aging process in which the temporarily sealed laminate is held in a high temperature range for a predetermined time. The aging temperature is, for example, 35°C or more and 85°C or less, or may be 40°C or more and 80°C or less. The aging time may be 10 hours or more, 20 hours or more.

[0061] 6.Through hole formation process 1(e), this step is a step of forming a through hole Q in the first member 30, which communicates with the liquid injection port P, after the battery processing step. The method of forming the through hole in the first member is not particularly limited, but for example, a method of making a hole using an appropriate punching tool (needle, punch, drill, etc.), a method of irradiating the first member with high-energy rays such as a laser, etc., can be appropriately adopted.

[0062] The through hole Q preferably penetrates the first member 30 in the x-axis direction. The first member 30 preferably has a plurality of through holes Q. In addition, in plan view in the x-axis direction, the through hole Q of the first member 30 preferably overlaps at least a portion of the liquid filling port P of the liquid filling frame 20. The shape of the through hole in plan view in the x-axis direction is not particularly limited, and examples of such a shape include a circle and a rectangle.

[0063] 7.Second sealing process As shown in FIG. 1(f), this process is a process in which, after the through hole forming process, a second member 40 having a resin layer B (resin layer 41) and a metal layer 42 is used, and the resin layer B of the second member is placed on the surface 30S of the first member opposite the liquid injection frame, with the x-axis direction as the normal direction, to cover the through hole Q while sealing the liquid injection port P.

[0064] 1(f), the second member 40 has a resin layer B (resin layer 41) and a metal layer 42. The second member 40 preferably has a resin layer C (resin layer 43) on the opposite side of the metal layer 42 to the resin layer B (resin layer 41). Each of the resin layer B and the resin layer C is preferably a single resin layer.

[0065] The metal constituting the metal layer is not particularly limited as long as it can exhibit barrier properties, and examples thereof include metals such as aluminum, stainless steel, titanium, nickel, iron, and copper, or alloys containing these metals. The thickness of the metal layer is preferably 10 μm or more, more preferably 30 μm or more. On the other hand, it is preferably 180 μm or less, more preferably 150 μm or less.

[0066] The resin layer B preferably contains a thermoplastic resin. When the resin layer B contains a thermoplastic resin, the first member 30 and the second member 40 can be easily welded together. Examples of the thermoplastic resin contained in the resin layer B include those exemplified for the first resin layer and the third resin layer in the first member. Among these, polyethylene is preferred. Examples of the resin contained in the resin layer C include those similar to those contained in the second resin layer in the first member. Among these, polyethylene terephthalate is preferred.

[0067] The second member 40 is preferably in the form of a film. By having the second member in the form of a film, the filling port of the filling frame can be easily welded and sealed while covering the through-hole of the first member.

[0068] The thickness of the second member is not particularly limited, and is preferably 100 μm or more, and more preferably 120 μm or more. On the other hand, it is preferably 200 μm or less, and more preferably 180 μm or less. The thickness of the second member is the thickness in the x-axis direction (T 40 ) In addition, when the second member is a laminate of multiple layers, the above thickness is the total thickness of the multiple layers included in the second member. This is because the rigidity of the second member is improved, and deformation during vacuum sealing can be suppressed.

[0069] The resin constituting the filling frame, the resin contained in the first resin layer and the third resin layer in the first member, and the resin contained in the resin layer B in the second member are preferably the same type, but may be different types. In the case of different types, it is preferable that the absolute value of the difference in solubility parameter (SP value) between the resin with the largest solubility parameter and the resin with the smallest solubility parameter among the above resins is within 3. This is because high weldability can be obtained.

[0070] 1(f), for example, a heat bar 60 heated to a predetermined temperature is pressed against the second member 40 from the side opposite to the first member 30, thereby welding the first member 30 and the second member 40 together, and the second member 40 covers the through-hole Q and seals the liquid injection port P. Note that the welding method is not limited to the above method, and can be performed by a general heating method. The second sealing step is preferably performed in a vacuumed chamber in a reduced pressure atmosphere.

[0071] The welding sealing conditions (heating temperature, pushing distance, time, etc.) in the second sealing step are not particularly limited. The heating temperature is preferably a temperature at which at least one of the resin contained in the resin layer A of the first member (when the resin layer A has a plurality of resin layers, the third resin layer arranged on the second member side) and the resin contained in the resin layer B of the second member softens or melts. The heating temperature is, for example, 80°C or more and 200°C or less, and may be 100°C or more and 180°C or less. The heating time is, for example, 10 seconds or more and 60 seconds or less, and may be 20 seconds or more and 60 seconds or less. The pushing distance is, for example, 0.2 mm or more and 3.0 mm or less, and may be 0.5 mm or more and 2.0 mm or less.

[0072] 8.Stacked battery The laminated battery manufactured by the manufacturing method of the laminated battery according to the present disclosure is similar to the content described in the section "B. Stacked battery" below.

[0073] B. Stacked battery FIG. 10 is a schematic cross-sectional view illustrating a stacked battery in the present disclosure. As shown in FIG. 10, the stacked battery 100 has an electrode stack 10 including a plurality of electrodes E stacked in the z-axis direction. The stacked battery 100 has the electrode stack 10, a resin-made liquid injection frame 20 that is disposed on a side surface SS of the electrode stack 10 and has a liquid injection port P for supplying an electrolyte solution to the inside of the electrode stack 10, a first member 30 that is disposed on a surface 20S of the liquid injection frame 20 opposite to the electrode stack 10, with the x-axis direction perpendicular to the z-axis direction as the normal direction, and a second member 40 that is disposed on a surface 30S of the first member 30 opposite to the liquid injection frame 20, with the x-axis direction as the normal direction. The first member 30 has a resin layer A (resin layer 31), and has a through hole Q that covers the liquid injection port P and communicates with the liquid injection port P. The second member 40 has, in order from the first member 30 side, a resin layer B (resin layer 41) and a metal layer 42, and seals the liquid injection port P while covering the through hole Q. The electrode stack 10 in FIG. 10 has bipolar electrodes BP1 and BP2.

[0074] According to the stacked battery of the present disclosure, a first member having a through hole is disposed between the second member and the liquid filling frame, thereby making it possible to suppress a decrease in structural reliability due to an increase in internal pressure during the battery processing step in the manufacturing process.

[0075] Furthermore, according to the present disclosure, as shown in FIG. 10, by disposing the first member 30 between the liquid filling frame 20 and the second member 40, even if the metal layer 42 of the second member 40 becomes exposed, there is a distance to the adjacent liquid filling port, so that a short circuit can be suppressed.

[0076] Furthermore, according to the present disclosure, by having the first member have a through hole, gas accumulation between the first member and the second member is suppressed, resulting in a stacked battery in which peeling between the first member and the second member can be suppressed.

[0077] 1. Electrode laminate The laminated battery of the present disclosure has an electrode laminate 10 including a plurality of electrodes E laminated in the z-axis direction, as shown in Fig. 10. The electrode laminate is the same as that described in the above section "A. Manufacturing method of laminated battery". In addition, the positive electrode layer 2, the negative electrode layer 3, and the separator 4 are each impregnated with an electrolyte.

[0078] 2. Liquid filling frame 10, the laminated battery of the present disclosure has a resin liquid filling frame 20 that is disposed on a side surface SS of the electrode laminate 10 and has a liquid filling port P for supplying an electrolyte solution to the inside of the electrode laminate. The liquid filling frame is the same as that described in the above section "A. Manufacturing method of laminated battery."

[0079] 3. First member 10, the first member in the present disclosure is disposed on a surface 20S of the liquid injection frame 20 opposite the electrode stack 10, with the normal direction being the x-axis direction orthogonal to the z-axis direction. The first member 30 has a resin layer A (resin layer 31), and has a through hole Q that covers the liquid injection port P and communicates with the liquid injection port P. The first member 30 is preferably welded to the liquid injection frame 20. The first member and the through hole in the first member are the same as those described in the above section "A. Manufacturing method of stacked battery."

[0080] 4. Second member As shown in FIG. 10, the stacked battery according to the present disclosure has a second member 40 disposed on a surface 30S of the first member 30 opposite the liquid injection frame 20, with the x-axis direction being the normal direction.

[0081] The second member has, in that order from the first member side, a resin layer B and a metal layer, and seals the liquid inlet while covering the through hole. As shown in Fig. 1, the second member 40 seals the liquid inlet P of the liquid inlet frame 20 while covering the through hole Q of the first member 30. The second member 40 is preferably welded to the first member 30. The second member is the same as that described in the above section "A. Manufacturing method of stacked battery".

[0082] 5.Other The laminated battery of the present disclosure generally has an electrolyte solution impregnated in the electrode laminate. As the electrolyte solution, for example, a known organic electrolyte solution used in a lithium ion secondary battery can be appropriately used.

[0083] 6.Stacked battery Specific examples of the laminated battery in the present disclosure include secondary batteries (e.g., lithium ion secondary batteries) and electric double layer capacitors. In addition, examples of applications of the laminated battery include power sources for vehicles such as hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), electric vehicles (BEVs), gasoline automobiles, and diesel automobiles. In particular, it is preferable to use the laminated battery as a driving power source for hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), or electric vehicles (BEVs). In addition, the laminated battery in the present disclosure may be used as a power source for moving objects other than vehicles (e.g., railways, ships, and aircraft), and may be used as a power source for electrical products such as information processing devices. EXAMPLES

[0084] The present disclosure will be further described below with reference to experimental examples.

[0085] (Experimental Example) Films 1 to 4 were prepared and evaluated as follows. The film 1 has a three-layer structure consisting of a first resin layer (PE layer) containing polyethylene, a second resin layer (PET layer) containing polyethylene terephthalate, and a third resin layer (PE layer) containing polyethylene. The film 2 has a two-layer structure consisting of a first resin layer (PE layer) containing polyethylene and a second resin layer (PET layer) containing polyethylene terephthalate. The film 3 has a four-layer structure consisting of a first resin layer (PPa layer) containing acid-modified polypropylene, a second resin layer (PEN layer) containing polyethylene naphthalate, a third resin layer (PPa layer) containing acid-modified polypropylene, and a fourth resin layer (PEa layer) containing acid-modified polyethylene, and further has a release PET layer on the surface of the fourth resin layer side. The thickness of the film 3 excluding the release PET layer is 105 μm. Film 4 is a 72 μm thick film having a three-layer structure consisting of a first resin layer (PPa layer) containing acid-modified polypropylene, a second resin layer (PEN layer) containing polyethylene naphthalate, and a third resin layer (PPa layer) containing acid-modified polypropylene. The acid-modified polypropylene and the acid-modified polyethylene in Film 3 and Film 4 are maleic anhydride-modified polypropylene and maleic anhydride-modified polyethylene, respectively.

[0086] (Experimental example 1): Productivity evaluation The above film 1 was placed on the injection frame, and the injection port was sealed by pressing a hot plate against it from above. If the film could be easily peeled off from the hot plate immediately after welding the above film 1, and there was no sticking of the film to the hot plate or flow of the resin, it was rated as A. On the other hand, if the film stuck to the hot plate or there was flow of the resin, it was rated as B. The results are shown in Table 1. Film 1 caused a melt flow in the PE layer.

[0087] Films 2 to 4 were evaluated in the same manner as Film 1. Film 2 was placed so that the first resin layer containing polyethylene faced the liquid pouring frame, and then welded. The PET layer prevented Film 2 from welding to the hot plate. Film 3 was placed so that the first resin layer containing acid-modified polypropylene faced the liquid pouring frame, and then welded. The release PET layer prevented Film 3 from welding to the hot plate. Film 4 was welded via a PET film or glass cloth, and thus prevented Film 2 from welding to the hot plate.

[0088] (Experimental Example 2): Evaluation of electrolyte resistance The above film 4 was welded onto the liquid injection frame, and the injection port was sealed. An electrolyte (electrolyte LiPF6 dissolved at 1.1 M in a mixed solvent of EC / DMC / EMC=3 / 4 / 3) was stored in the liquid injection frame to which the film was welded, sealed, and stored at 65° C. for 80 hours. After storage, a pressure resistance evaluation was performed, and a pressure resistance value of 0.40 MPa or more was rated as A.

[0089] [Table 1]

[0090] (Experimental example 3): Pressure resistance evaluation The injection frame, which is an injection molded product, was used, and the film 4 was placed on the injection frame, and the injection port was sealed by pressing a hot plate from above. The injection frame side was fixed to a base, and compressed air was injected from the bottom of the injection frame on the opposite side to the film 1. The internal pressure of the injection frame was increased, and the pressure (pressure resistance value) until the film 1 peeled off from the injection frame or burst was measured (Experimental Example 3-1). In addition, a pressure resistance evaluation was performed in the same manner as above, except that a film 5 having a PET layer, a metal aluminum layer, and a PE resin layer in this order was used, and the PE layer of the film 5 was placed so as to face the injection frame (Reference Example). In addition, the film 4 was used, and after the film 4 was welded to the injection frame, the film 5 was further welded to the film 4. The pressure resistance evaluation was performed in the same manner as above, and the pressure resistance value was measured (Experimental Example 3-2). The results are shown in Table 2.

[0091] [Table 2]

[0092] Although the pressure resistance strength is lower when film 4 is welded under film 5 (Experimental Example 3-2) than when the injection frame is directly sealed with film 5 (Reference Example), it was confirmed that sufficient pressure resistance strength against an increase in internal pressure is obtained.

[0093] The present disclosure is not limited to the above-described embodiments. The above-described embodiments are merely examples, and anything that has substantially the same configuration as the technical idea described in the claims of the present disclosure and exhibits similar effects is included in the technical scope of the present disclosure. [Explanation of symbols]

[0094] 1...Current collector 2…Positive electrode layer 3...Negative electrode layer 4…Separator 5…Resin material 6…Nesting 10...Electrode laminate 20...Filling frame 30…First member 40…Second member 100…Stacked battery O…Communication hole P…Liquid inlet Q...Through hole

Claims

1. a preparation step of preparing an electrode stack including a plurality of electrodes stacked in the z-axis direction; a placement step of placing a resin liquid pouring frame having a liquid pouring port on a side surface of the electrode stack; a liquid injection step of injecting an electrolyte solution into the electrode stack from the liquid injection port of the liquid injection frame; a first sealing step of sealing the liquid pouring port by disposing a first member having a resin layer A on a surface of the liquid pouring frame whose normal direction is the x-axis direction perpendicular to the z-axis direction after the liquid pouring step; a battery treatment step of performing at least one of charging and aging after the first sealing step; a through-hole forming step of forming a through-hole in the first member, the through-hole communicating with the liquid injection port, after the battery treatment step; a second sealing step of using a second member having a resin layer B and a metal layer, and disposing the resin layer B of the second member on a surface of the first member whose normal direction is in the x-axis direction, thereby covering the through hole and sealing the liquid injection port.

2. The method for manufacturing a laminated battery according to claim 1 , wherein the first member and the second member are in the form of a film.

3. The method for manufacturing a laminated battery according to claim 1 , wherein the first member has a plurality of resin layers as the resin layer A.

4. The method for manufacturing a laminated battery according to claim 1 , wherein the second member has a resin layer C on an opposite side of the metal layer to the resin layer B.

5. 2. The method for manufacturing a laminated battery according to claim 1, wherein the electrode laminate includes a bipolar electrode having a current collector, a positive electrode layer disposed on one surface of the current collector, and a negative electrode layer disposed on the other surface of the current collector.

6. an electrode stack including a plurality of electrodes stacked in the z-axis direction; a resin liquid pouring frame disposed on a side surface of the electrode stack and having a liquid pouring port for supplying an electrolyte solution to the inside of the electrode stack; a first member disposed on a surface of the liquid injection frame opposite to the electrode stack, the surface having a normal direction in an x-axis direction perpendicular to the z-axis direction; a second member disposed on a surface of the first member opposite to the liquid injection frame, the surface having a normal direction in the x-axis direction; the first member has a resin layer A, and has a through hole that covers the liquid injection hole and communicates with the liquid injection hole; the second member has, in order from the first member side, a resin layer B and a metal layer, and covers the through hole and seals the liquid injection hole.

7. The stacked battery according to claim 6 , wherein the first member and the second member are in the form of a film.

8. The laminated battery according to claim 6 , wherein the first member has a plurality of resin layers as the resin layer A.

9. The laminated battery according to claim 6 , wherein the second member has a resin layer C on the opposite side of the metal layer to the resin layer B.

10. 7. The laminated battery according to claim 6, wherein the electrode stack includes a bipolar electrode having a current collector, a positive electrode layer disposed on one surface of the current collector, and a negative electrode layer disposed on the other surface of the current collector.

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