Manufacturing method for multilayer electrodes

Abstract

To improve the productivity of multilayer electrode bodies. [Solution] The method for manufacturing a laminated electrode body disclosed herein includes a first placement step of placing a first electrode plate 210 on a separator 26 and pressing the first electrode plate 210 with a first fixing member 310; a first folding step of folding the separator 26 so as to sandwich the first electrode plate 210; a second placement step of placing a second electrode plate 220 on the separator 26 so as to overlap the first electrode plate 210 sandwiched between the separator 26; a position information acquisition step of acquiring position information of the first electrode plate 210 sandwiched between the separator 26; a removal step of removing the first fixing member 310 before the position information acquisition step; a determination step of determining whether or not the first electrode plate 210 is positioned to satisfy predetermined criteria; and a correction step of correcting the position of the first electrode plate 210 if it is determined that the determination step is not to satisfy the criteria.

Description

Technical Field

[0001] The present disclosure relates to a method for manufacturing a laminated electrode body.

Background Art

[0002] Japanese Patent Application Laid-Open No. 2022-18024 discloses a manufacturing apparatus for a laminated electrode body in which negative electrode plates and positive electrode plates are alternately arranged and laminated at the valley-fold portions of a separator folded in a zigzag (bellows) shape. In this manufacturing apparatus, the position information of the electrode plate laminated at the uppermost part is acquired, and the position of the uppermost electrode plate is adjusted to an appropriate position.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in an example of manufacturing a laminated electrode body, a new electrode plate is placed on the laminate in a state where the already laminated electrode plate is fixed with a fixing member (for example, a fixing claw). After placing the new electrode plate, the fixing member is removed from the laminate. At this time, friction may occur between the fixing member and the laminated electrode plate, and the position of the electrode plate may shift from an appropriate position. Since an electrode body with a shifted electrode plate becomes a defective product, the productivity decreases.

Means for Solving the Problems

[0005] One aspect of the technology disclosed herein is a method for manufacturing a stacked electrode body with a zigzag structure, in which strip-shaped separators are alternately folded to form a zigzag shape, and electrode plates are alternately sandwiched between the zigzag-shaped separators. An example of this manufacturing method includes: a first placement step of placing a first electrode plate on the separator and holding the first electrode plate with a first fixing member; a first folding step of folding the separator back so as to sandwich the first electrode plate after the first placement step; a second placement step of placing a second electrode plate on the separator so as to overlap the first electrode plate sandwiched between the separators after the first folding step; a position information acquisition step of acquiring position information of the first electrode plate sandwiched between the separators after the second placement step; a removal step of removing the first fixing member before the position information acquisition step; a determination step of determining whether the first electrode plate is positioned to satisfy predetermined criteria based on the acquired position information of the first electrode plate; and a correction step of correcting the position of the first electrode plate if it is determined that it is not in the determination step.

[0006] In the above manufacturing method, the displacement of the electrode body caused by the removal of the fixing member can be corrected, thereby improving productivity. [Brief explanation of the drawing]

[0007] [Figure 1] Figure 1 is a schematic diagram showing the structure of an energy storage device according to one embodiment. [Figure 2] Figure 2 is a schematic diagram showing the structure of a laminated electrode body according to one embodiment. [Figure 3] Figure 3 is a flowchart that roughly illustrates one example of a method for manufacturing a multilayer electrode. [Figure 4] Figure 4 is a schematic diagram showing the assembly of the multilayer electrode during the manufacturing process. [Figure 5] Figure 5 is a schematic diagram showing the assembly after the first mounting process S10. [Figure 6] Figure 6 is a schematic diagram of the assembly shown in Figure 5, viewed from above (plan view). [Figure 7] Figure 7 is a schematic diagram showing the assembly after the first folding process S20. [Figure 8] Figure 8 is a schematic diagram showing the assembly after the second mounting process S30. [Figure 9] Figure 9 is a schematic diagram of the assembly shown in Figure 8, viewed from above (plan view). [Figure 10] Figure 10 is a schematic diagram showing the assembly after the disassembly process S40. [Figure 11] Figure 11 is a schematic diagram of the assembly shown in Figure 10, viewed from above (plan view). [Figure 12] Figure 12 is a schematic diagram showing an assembly in which the first electrode plate has been misaligned after the removal process S40. [Figure 13] Figure 13 is a schematic diagram of the assembly shown in Figure 12, viewed from above (plan view). [Figure 14] Figure 14 is a schematic diagram illustrating the position correction of the first electrode plate. [Figure 15] Figure 15 is a diagram corresponding to Figure 11 in an example where the first electrode plate is the positive electrode plate and the second electrode plate is the negative electrode plate. [Figure 16] Figure 16 is a diagram corresponding to Figure 13 in an example where the first electrode plate is the positive electrode plate and the second electrode plate is the negative electrode plate. [Figure 17] Figure 17 is a diagram corresponding to Figure 13, showing an example of a case where the positional displacement of the first electrode plate occurs after the removal process S40. [Modes for carrying out the invention]

[0008] The following describes some examples of the technologies disclosed herein with reference to the drawings. In the drawings, components and parts that perform the same function may be denoted by the same reference numerals. Matters other than those specifically mentioned herein but necessary for carrying out the technologies disclosed herein (for example, the general configuration and manufacturing process of energy storage devices that do not characterize the technologies disclosed herein) can be understood as design matters for those skilled in the art based on the prior art. The technologies disclosed herein can be carried out based on the contents disclosed herein and the common technical knowledge of the art. Furthermore, the notation "A to B" indicating a range herein shall encompass the meaning of "greater than A and less than or equal to B," as well as "greater than A" and "less than B."

[0009] In this specification, "energy storage device" refers to any device that can be repeatedly charged and discharged by the movement of a charge carrier between a positive electrode and a negative electrode via an electrolyte. The concept of energy storage devices encompasses secondary batteries such as lithium-ion secondary batteries and nickel-metal hydride batteries, and capacitors such as lithium-ion capacitors and electric double-layer capacitors.

[0010] <1. Structure of an energy storage device> Figure 1 is a schematic diagram showing the structure of an energy storage device 1 according to one embodiment. As shown in Figure 1, the energy storage device 1 comprises a case 10, a laminated electrode body 20, a positive electrode terminal 30, and a negative electrode terminal 40. Although not shown in the figure, the energy storage device 1 also comprises an electrolyte. The energy storage device 1 houses the laminated electrode body 20 and the electrolyte within the case 10, which has the positive electrode terminal 30 and the negative electrode terminal 40. The energy storage device 1 is a lithium-ion secondary battery in this case.

[0011] The case 10 is a housing that houses the laminated electrode body 20 and the electrolytic solution. The shape, material, size, etc. of the case 10 are not particularly limited as long as the laminated electrode body 20 and the electrolytic solution can be housed inside. Here, the case 10 is a rectangular parallelepiped square case. In some examples, the case 10 may include a cylindrical case body having openings at both ends and sealing plates for the openings at both ends. The case 10 can be made of a metal material such as aluminum, for example. In some examples, the case 10 may be composed of a laminate film having a multilayer structure including a resin layer and a metal layer. The case 10 includes a thin safety valve 12 that is opened when the internal pressure of the case 10 rises above a predetermined level. Further, the case 10 may include an injection port (not shown) for injecting the electrolytic solution.

[0012] The positive electrode terminal 30 and the negative electrode terminal 40 are exposed on the outer surface of the case 10, respectively. Here, the positive electrode terminal 30 and the negative electrode terminal 40 are fixed to the same surface of the case 10, respectively. In some examples, the positive electrode terminal 30 and the negative electrode terminal 40 may be fixed to different surfaces.

[0013] The positive electrode terminal 30 is preferably made of metal, and more preferably made of aluminum or an aluminum alloy, for example. As shown in FIG. 1, the positive electrode terminal 30 is electrically connected to the positive electrode plate 22 (specifically, the positive electrode tab 22t) of the laminated electrode body 20 through the positive electrode current collector 32 inside the case 10. The negative electrode terminal 40 is preferably made of metal, and more preferably made of copper or a copper alloy, for example. As shown in FIG. 1, the negative electrode terminal 40 is electrically connected to the negative electrode plate 24 (specifically, the negative electrode tab 24t) of the laminated electrode body 20 through the negative electrode current collector 42 inside the case 10.

[0014] The electrolyte may be the same as the conventional one and is not particularly limited. The electrolyte is, for example, a non-aqueous electrolyte containing a non-aqueous solvent (organic solvent) and a supporting salt (electrolyte salt, such as a lithium salt or a sodium salt). As an example of the non-aqueous solvent, carbonates such as ethylene carbonate, dimethyl carbonate, and ethyl methyl carbonate can be mentioned. As an example of the supporting salt, a fluorine-containing lithium salt such as lithium hexafluorophosphate (LiPF6) can be mentioned. The electrolyte is typically liquid, but may also be gel-like.

[0015] The laminated electrode body 20 is housed inside the case 10. The number of laminated electrode bodies 20 arranged inside one case 10 may be one or two or more (plural). Further, the laminated electrode body 20 is housed inside the case 10 in a state covered with a resin-made insulating sheet 50 (electrode body holder) here.

[0016] FIG. 2 is a schematic diagram showing the structure of the laminated electrode body 20 according to an embodiment. As shown in FIG. 2, the laminated electrode body 20 includes a plurality of positive electrode plates 22, a plurality of negative electrode plates 24, and a zigzag separator 26. The direction in which the positive electrode plate 22 and the negative electrode plate 24 face each other is the lamination direction.

[0017] The laminated electrode body 20 has a zigzag structure in which a plurality of positive electrode plates 22 and a plurality of negative electrode plates 24 are alternately sandwiched between the zigzag separators 26. The separator 26 is formed in a zigzag shape by alternately folding a belt-shaped separator sheet in mountain folds and valley folds. The separator 26 has a first surface 26a and a second surface 26b. The second surface 26b is the surface on the opposite side of the first surface 26a. The negative electrode plate 24 is sandwiched so as to face the first surface 26a of the separator 26 folded in a zigzag shape. The positive electrode plate 22 is sandwiched so as to face the second surface 26b of the separator 26 folded in a zigzag shape.

[0018] The positive electrode plate 22 may be the same as in the conventional design and is not particularly limited. The positive electrode plate 22 is substantially rectangular in plan view. Typically, the positive electrode plate 22 comprises a positive electrode current collector 22a and a positive electrode active material layer 22b (see Figure 2) fixed to at least one surface (here, both surfaces) of the positive electrode current collector 22a. The positive electrode current collector 22a is preferably a metal foil, and is preferably composed of aluminum or an aluminum alloy, for example. The positive electrode active material layer 22b contains a positive electrode active material capable of reversibly intercepting and releasing charge carriers. The positive electrode active material may be the same as in the conventional design and is not particularly limited. An example of a positive electrode active material is a lithium transition metal composite oxide. The positive electrode active material layer 22b may also contain optional components other than the positive electrode active material, such as a binder or conductive material.

[0019] The positive electrode plate 22 has a convex positive electrode tab 22t protruding outward from its end (see Figure 1). The positive electrode tab 22t does not have a positive electrode active material layer 22b formed on it, and has a portion where the positive electrode current collector 22a is exposed (current collector exposed portion). Multiple positive electrode tabs 22t are stacked and electrically connected to the positive electrode terminal 30 via the positive electrode current collector portion 32. A positive electrode protective layer containing an inorganic filler may be provided at the boundary between the positive electrode tab 22t and the positive electrode active material layer 22b.

[0020] The negative electrode plate 24 may be the same as in the conventional design and is not particularly limited. In plan view, the negative electrode plate 24 is substantially rectangular in shape. Typically, the negative electrode plate 24 comprises a negative electrode current collector 24a and a negative electrode active material layer 24b (see Figure 2) fixed to at least one surface (here, both surfaces) of the negative electrode current collector 24a. The negative electrode current collector 24a is preferably a metal foil, and is preferably composed of copper or a copper alloy, for example. The negative electrode active material layer 24b contains a negative electrode active material capable of reversibly intercepting and releasing charge carriers. The negative electrode active material may be the same as in the conventional design and is not particularly limited. Examples of negative electrode active materials include carbon materials such as graphite and silicon-based materials. The negative electrode active material layer 24b may also contain optional components other than the negative electrode active material, such as binders, thickeners, and dispersants.

[0021] In a plan view, it is preferable that the negative electrode active material layer 24b has a larger area than the positive electrode active material layer 22b. This improves the acceptance of charge carriers in the negative electrode active material and suppresses the deposition of charge carriers. Here, in the stacking direction of the laminated electrode body 20, the entire positive electrode active material layer 22b faces the negative electrode active material layer 24b. Furthermore, the negative electrode active material layer 24b is arranged to have a portion that protrudes outward from the positive electrode active material layer 22b in a direction perpendicular to the stacking direction of the laminated electrode body 20 (see Figure 9 described later).

[0022] The negative electrode plate 24 has convex negative electrode tabs 24t protruding outward from its ends (see Figure 1). The negative electrode tabs 24t do not have a negative electrode active material layer 24b formed on them, and have a portion where the negative electrode current collector 24a is exposed (current collector exposed portion). Multiple negative electrode tabs 24t are stacked and electrically connected to the negative electrode terminal 40 via the negative electrode current collector portion 42.

[0023] The separator 26 is interposed between the positive electrode plate 22 and the negative electrode plate 24. The separator 26 is an insulating sheet with multiple fine through-holes through which charge carriers can pass. By interposing the separator 26 between the positive electrode plate 22 and the negative electrode plate 24, contact between the positive electrode plate 22 and the negative electrode plate 24 is prevented, and charge carriers (e.g., lithium ions) can be moved between the positive electrode plate 22 and the negative electrode plate 24.

[0024] Although not shown in the figures, the separator 26 preferably comprises a separator substrate and one or more heat-resistant layers (HRL layers). The heat-resistant layers are preferably formed on at least one surface of the separator substrate. The heat-resistant layers may be provided on only one surface of the separator substrate, or on both surfaces.

[0025] The separator substrate can be the same as conventional substrates and is not particularly limited. The separator substrate may be a single-layer structure, or it may be a structure of two or more layers with different properties and characteristics (such as thickness and porosity), for example, a three-layer structure. The separator substrate is typically made of resin, and is preferably made of polyolefin resin. The polyolefin resin is preferably polyethylene (PE), polypropylene (PP), or a mixture thereof, and is more preferably made of PE.

[0026] The heat-resistant layer typically contains an inorganic filler and a heat-resistant layer binder. By providing a heat-resistant layer, thermal shrinkage of the separator 26 can be suppressed, contributing to improved safety of the energy storage device 1. As the inorganic filler, ceramic particles such as alumina, zirconia, boehmite, aluminum hydroxide, silica, and titania are preferred, and compounds containing aluminum are particularly preferred from the viewpoint of suppressing thermal shrinkage of the separator 26. Examples of heat-resistant layer binders include acrylic resins, fluororesins, urethane resins, ethylene vinyl acetate resins, and epoxy resins. Among these, acrylic resins are preferred.

[0027] As shown in Figure 2, the separator 26 is folded in a zigzag pattern (also called a bellows pattern) by being folded back alternately at predetermined intervals (length W). The separator 26 has a flat portion 26f, a first folded portion 26c1, and a second folded portion 26c2. The flat portion 26f is located between the first folded portion 26c1 and the second folded portion 26c2.

[0028] The flat portion 26f of the separator 26 is the portion facing at least one of the positive electrode plate 22 (typically the positive electrode active material layer 22b) and the negative electrode plate 24 (typically the negative electrode active material layer 24b). It has an area that covers the entire positive electrode active material layer 22b and the negative electrode active material layer 24b. In the direction in which the first folded portion 26c1 and the second folded portion 26c2 face each other (left-right direction in Figure 2), the length W of the separator 26 is preferably longer than the lengths of the positive electrode plate 22 (typically the positive electrode active material layer 22b) and the negative electrode plate 24 (typically the negative electrode active material layer 24b).

[0029] The first folded portion 26c1 and the second folded portion 26c2 are parts that do not face either the positive electrode plate 22 or the negative electrode plate 24. In other words, the first folded portion 26c1 and the second folded portion 26c2 are protruding portions that extend beyond the flat portion 26f. Here, the first folded portion 26c1 and the second folded portion 26c2 consist only of the separator 26.

[0030] The end of the separator 26 is wrapped around the outermost part of the zigzag structure in which the positive electrode plate 22 and the negative electrode plate 24 are sandwiched, forming the outer surface of the laminated electrode body 20. A winding stopper tape 29 is attached to the end of the separator 26 to prevent winding slack.

[0031] The energy storage device 1 can be used for various applications. Suitable applications include automotive applications, specifically as a power source for vehicles such as battery electric vehicles (BEVs), hybrid electric vehicles (HEVs), and plug-in hybrid electric vehicles (PHEVs). The energy storage device 1 can also be used as a battery for small-scale power storage devices. The energy storage device 1 can typically be used in the form of a battery module, which consists of multiple devices connected in series and / or parallel.

[0032] <2. Manufacturing method of laminated electrode body> The manufacturing method disclosed herein will be explained below, using the manufacturing method of the laminated electrode body 20 as an example. Figure 3 is a flowchart roughly showing an example of the manufacturing method of the laminated electrode body 20. As shown in Figure 3, the manufacturing method of the laminated electrode body 20 includes a first placement step S10, a first folding step S20, a second placement step S30, a removal step S40, a position information acquisition step S50, a determination step S60, and a correction step S70. In some examples, other steps may be included at any stage. Also, in some examples, unnecessary steps may be omitted.

[0033] Figure 4 is a schematic diagram showing the assembly 200 during the manufacturing process of the laminated electrode body 20. Figure 5 is a schematic diagram showing the assembly 200 after the first placement process S10. Figure 6 is a schematic diagram of the assembly 200 of Figure 5 viewed from above (plan view). In Figure 6, the separator 26 and the equipment (lamination stage 100, rollers 110, etc.) are not shown. Also, in the drawings explaining the manufacturing method (Figures 4 to 17), the positive electrode tab 22t and negative electrode tab 24t are not shown. The symbols L, R, F, Rr, U, and D in the drawings represent left, right, front, back, up, and down, respectively. The symbols X, Y, and Z in the drawings represent the long side direction, the short side direction perpendicular to the long side direction, and the lamination direction of the assembly 200, respectively. However, these are merely directions for the sake of explanation and do not limit the installation configuration of the assembly 200 in any way. The assembly 200 refers to the laminate formed during the manufacturing process of the laminated electrode body 20.

[0034] As shown in Figure 4, the assembly 200 is placed on the stacking stage 100. The stacking stage 100 is a stage for stacking separators 26, positive electrode plates 22, and negative electrode plates 24. Here, the assembly 200 has a stacked structure in which separators 26, negative electrode plates 24, separators 26, and positive electrode plates 22 are repeatedly stacked from the side closest to the stacking stage 100. Here, the long side direction X of the assembly 200 coincides with the long side direction of the electrode plates and the long side direction of the separators 26. In the assembly 200 shown in Figure 4, separators 26 are stacked on top. The assembly 200 in Figure 4 is manufactured, for example, by repeating the first placement step S10 and the first folding step S20 described below. The separators 26 are supplied to the assembly 200 by rollers 110.

[0035] (1) First placement process S10 The first placement step S10 includes placing an electrode plate (hereinafter also referred to as the "first electrode plate 210") on the assembly 200. Here, the negative electrode plate 24 is placed as the first electrode plate 210 on a separator 26 located at the top of the stacking direction Z of the assembly 200 shown in Figure 4 (see Figure 5). The first electrode plate 210 is placed on the separator 26 so as to overlap the positive electrode plate 22, which is the uppermost of the electrode plates included in the assembly 200, in a plan view. It is preferable that the first electrode plate 210 is positioned so that the outer edge of the positive electrode plate 22 and the outer edge of the first electrode plate 210 do not intersect in a plan view. Here, the negative electrode plate 24 has a larger area than the positive electrode plate 22. Therefore, the negative electrode plate 24 as the first electrode plate 210 is positioned so as to cover the entire positive electrode plate 22 without its outer edge intersecting with the outer edge of the positive electrode plate 22 in a plan view. In this specification, the positive electrode tab 22t and the negative electrode tab 24t are not included in the term "outer edge" as used herein.

[0036] As shown in Figure 5, the first electrode plate 210, positioned at the top of the assembly 200, is fixed by the first fixing member 310. Here, the first fixing member 310 is positioned on top of the first electrode plate 210 and holds the first electrode plate 210 in the stacking direction Z. The first fixing member 310 is positioned at the end of the first electrode plate 210 in the long side direction X (left side in Figure 5). This prevents the first electrode plate 210 from shifting position during the first folding step S20, which will be described later.

[0037] As shown in Figure 5, it is preferable that a portion of the first fixing member 310 protrudes from the outer edge of the first electrode plate 210 in the long-side direction X (the region where the first folded portion 26c1 is formed). This reduces the friction that occurs between the first fixing member 310 and the first electrode plate 210 when the first fixing member 310 is removed.

[0038] After the first electrode plate 210 is held in place by the first fixing member 310, the position information of the first electrode plate 210 may be acquired by the imaging device 400. The imaging device 400 is, for example, a camera. As shown in Figure 5, the imaging device 400 is installed, for example, above the assembly 200. The imaging device 400 photographs the assembly 200 so as to include the position information of the first electrode plate 210 and the separator 26 positioned below the first electrode plate 210. Here, the imaging device 400 acquires an image obtained by irradiating with visible light. The imaging device 400 may also be provided with visible light irradiation means. From the acquired image, for example, it can be confirmed whether the first electrode plate 210 is positioned inside the separator 26. Also, from the acquired image, it can be confirmed whether the first fixing member 310 is properly positioned.

[0039] As shown in Figure 6, the first fixing member 310 here includes a first fixing part 310a and a second fixing part 310b. The first fixing part 310a extends from one side of the first electrode plate 210 in the short-side direction Y (the Rr side in Figure 6) and holds the first electrode plate 210 in place. In the removal process S40 described later, the first fixing part 310a is pulled out from the first electrode plate 210 towards the Rr side in the short-side direction Y. The second fixing part 310b extends from the other side of the first electrode plate 210 in the short-side direction Y (the F side in Figure 6) and holds the first electrode plate 210 in place. In the removal process S40 described later, the second fixing part 310b is pulled out from the first electrode plate 210 towards the F side in the short-side direction Y. This makes it easier to remove the first fixing part 310a and the second fixing part 310b from the assembly 200.

[0040] As shown in Figure 6, it is preferable that the first fixing member 310 is positioned to press down on both corners of one end of the first electrode plate 210 in the long side direction X (the left side in Figure 6). In Figure 6, the first fixing part 310a and the second fixing part 310b each press down on one corner of the first electrode plate 210. By pressing down on both corners of the end of the first electrode plate 210 in the long side direction X, the position of the first electrode plate 210 is more securely fixed. Furthermore, if diagonal corners of the first electrode plate 210 are pressed down, wrinkles may occur in the separator 26, so it is preferable to press down on both corners of one end of the first electrode plate 210 (in this case, the left side in Figure 6).

[0041] A first region 212 is provided between the first fixing portion 310a and the second fixing portion 310b, in which the first electrode plate 210 is not directly pressed by the first fixing member 310. This reduces friction when the first fixing member 310 is withdrawn.

[0042] (2) First folding process S20 The first folding step S20 includes folding the separator 26 so as to sandwich the first electrode plate 210, which was placed on top of the assembly 200 in the first placement step S10. Figure 7 is a schematic diagram showing the assembly 200 after the first folding step S20. As shown in Figure 7, the first folded portion 26c1 is formed by folding the separator 26 from one side (left side in Figure 7) to the other side (right side in Figure 7) in the long side direction X of the assembly 200. The separator 26 folded in the first folded portion 26c1 extends in the long side direction X of the assembly 200 so as to sandwich both the first fixing member 310 and the first electrode plate 210. The first folded portion 26c1 can be formed by scanning the roller 110 that supplies the separator 26 to the assembly 200 in the long side direction X. Furthermore, the first folded portion 26c1 can also be formed by scanning the stacking stage 100 in the long side direction X to move the assembly 200.

[0043] (3) Second placement process S30 The second placement step S30 includes placing the second electrode plate 220 on the separator 26 located at the top of the assembly 200 in the stacking direction Z, after the first folding step S20. Figure 8 is a schematic diagram showing the assembly 200 after the second placement step S30. Figure 9 is a schematic diagram of the assembly 200 of Figure 8 viewed from above (plan view). In Figure 9, the separator 26 and the apparatus (stacking stage 100, roller 110, etc.) are not shown. The second electrode plate 220 is here the positive electrode plate 22. The second electrode plate 220 is stacked on the first electrode plate 210 via the separator 26. As shown in Figure 9, the second electrode plate 220 is positioned so that, in plan view, the outer edge of the first electrode plate 210, which is the uppermost layer of electrode plates included in the assembly 200, and the outer edge of the second electrode plate 220 do not intersect. In this configuration, the second electrode plate 220, which is the positive electrode plate 22, has a smaller area than the first electrode plate 210, which is the negative electrode plate 24. Therefore, the second electrode plate 220 is positioned inward from the outer edge of the first electrode plate 210. As shown in Figure 8, a portion of the second electrode plate 220 may be superimposed on the first fixing member 310.

[0044] As shown in Figure 8, the second electrode plate 220, positioned at the top of the assembly 200, is fixed by the second fixing member 320. Here, the second fixing member 320 is positioned on top of the second electrode plate 220 and holds the second electrode plate 220 in the stacking direction Z. The second fixing member 320 is positioned at the end of the second electrode plate 220 in the long side direction X (right side in Figure 8). The second fixing member 320 fixes the end of the assembly 200 opposite to the first fixing member 310.

[0045] As shown in Figure 8, it is preferable that a portion of the second fixing member 320 protrudes from the outer edge of the second electrode plate 220 in the long-side direction X (the region where the second folded portion 26c2 is formed). This reduces the friction that occurs between the second fixing member 320 and the second electrode plate 220 when the second fixing member 320 is removed.

[0046] After the second electrode plate 220 is held in place by the second fixing member 320, the position information of the second electrode plate 220 may be acquired by the imaging device 400. As shown in Figure 8, the imaging device 400 is installed, for example, above the assembly 200. The imaging device 400 photographs the assembly 200 so as to include the position information of the second electrode plate 220 and the separator 26 positioned below the second electrode plate 220. Here, the imaging device 400 acquires an image obtained by irradiating with visible light. From the acquired image, for example, it can be confirmed whether the second electrode plate 220 is positioned inside the separator 26. Also, from the acquired image, it can be confirmed whether the second fixing member 320 is properly positioned.

[0047] As shown in Figure 9, the second fixing member 320 here includes a third fixing portion 320a and a fourth fixing portion 320b. The third fixing portion 320a extends from one side of the second electrode plate 220 in the short-side direction Y (the Rr side in Figure 9) and holds the second electrode plate 220 in place. The fourth fixing portion 320b extends from the other side of the second electrode plate 220 in the short-side direction Y (the F side in Figure 9) and holds the second electrode plate 220 in place.

[0048] As shown in Figure 9, it is preferable that the second fixing member 320 is positioned to press against the corners on both sides of the end of the second electrode plate 220 in the long side direction X (right side in Figure 9). In Figure 9, the third fixing part 320a and the fourth fixing part 320b each press against one corner of the second electrode plate 220. By pressing against the corners on both sides of the end of the second electrode plate 220 in the long side direction X, the position of the second electrode plate 220 is more securely fixed.

[0049] (4) Removal process S40 The removal step S40 includes removing the first fixing member 310 from the assembly 200. The first fixing member 310 is removed, for example, after the second electrode plate 220 is placed on the top of the assembly 200. The first fixing member 310 can be removed, for example, by scanning (pulling out) the first fixing member 310 in the short-side direction Y.

[0050] Incidentally, as shown in Figure 8, the first fixing member 310 is positioned between the first electrode plate 210 and the separator 26. Therefore, when removing the first fixing member 310, friction occurs at the contact points between the first fixing member 310 and the first electrode plate 210, and between the first fixing member 310 and the separator 26. As a result, the position of the first electrode plate 210 may shift when the first fixing member 310 is removed. If the electrode plate shifts, charge carriers (e.g., lithium) are more likely to precipitate during charging and discharging, which can reduce capacity. A laminated electrode body with an electrode plate displacement exceeding a certain standard may be considered a defective product. Therefore, in order to increase production, a technology to correct the displacement of the electrode plate that may occur when the fixing member is removed is desired.

[0051] The removal process S40 may be performed before the position information acquisition process S50, which will be described later. It is preferable to remove the first fixing member 310 after the second fixing member 320 has pressed the second electrode plate 220 in the stacking direction Z. This allows the first fixing member 310 to be removed while the assembly 200 is fixed by the second fixing member 320, making it less likely for the first electrode plate 210 to shift position. In some examples, the first fixing member 310 may be removed at the same time as the second fixing member 320 is placed, or it may be removed before the second fixing member 320 is placed.

[0052] (5) Location information acquisition step S50 The position information acquisition step S50 includes acquiring position information of the first electrode plate 210 sandwiched between the separator 26. Here, the position information acquisition step S50 is performed after the second mounting step S30. Figure 10 is a schematic diagram showing the assembly 200 after the removal step S40. Figure 11 is a schematic diagram of the assembly 200 of Figure 10 viewed from above (plan view). In Figure 11, the separator 26 and the equipment (stacking stage 100, roller 110, etc.) are not shown. Figure 12 is a schematic diagram showing the assembly 200 after the removal step S40 in which the position of the first electrode plate 210 has shifted. Figure 13 is a schematic diagram of the assembly 200 of Figure 12 viewed from above (plan view). In Figure 13, the separator 26 and the equipment (stacking stage 100, roller 110, etc.) are not shown. In this specification, "location information" includes information about the relative positional relationship between the object and other components.

[0053] The positional information of the first electrode plate 210 is acquired, for example, by an imaging device 400. As shown in Figure 10, the imaging device 400 is installed, for example, above the assembly 200. The imaging device 400 photographs the assembly 200 from the stacking direction Z (the direction in which the first electrode plate 210 and the second electrode plate 220 are stacked). Since the second electrode plate 220 is placed on top of the assembly 200, the image captured will include at least the second electrode plate 220. The image captured here may be, for example, an image obtained by irradiating with light in a wavelength band that passes through the separator 26. Light in a wavelength band that passes through the separator 26 may be, for example, infrared light. The imaging device 400 may be configured to irradiate with light in a wavelength band that passes through the separator 26. From the obtained image, the positional information of the first electrode plate 210 sandwiched between the separators 26 can be acquired. For example, an image is obtained showing the outer edges of the first electrode plate 210 and the second electrode plate 220, as shown in Figure 11. Here, since the area of ​​the second electrode plate 220 is smaller than the area of ​​the first electrode plate 210, it is possible to photograph the outer edges of both. This allows information about the positional relationship between the first electrode plate 210 and the second electrode plate 220 to be obtained.

[0054] (6) Judgment step S60 The determination step S60 includes determining whether the first electrode plate 210 is positioned in a location that satisfies predetermined criteria, based on the position information of the first electrode plate 210 acquired in the position information acquisition step S50. For example, it determines whether a predetermined side constituting the outer edge of the first electrode plate 210 and a predetermined side constituting the outer edge of the second electrode plate 220 intersect. Here, as shown in Figure 11, the predetermined side of the first electrode plate 210 is the long side, the first side 210a. Similarly, the predetermined side of the second electrode plate 220 is the long side, the second side 220a. The first side 210a of the first electrode plate 210 is the side below the second side 220a of the second electrode plate 220 in the stacking direction Z. In other words, the first side 210a of the first electrode plate 210 and the second side 220a of the second electrode plate 220 are in a corresponding positional relationship. Furthermore, it is preferable that the first side 210a of the first electrode plate 210 and the second side 220a of the second electrode plate 220 are sides that do not have electrode tabs.

[0055] In Figure 11, the first side 210a of the first electrode plate 210 and the second side 220a of the second electrode plate 220 do not intersect. This case is judged as "positive". A "positive" result indicates that there is little to no displacement of the first electrode plate 210 when the first fixing member 310 is removed.

[0056] In Figure 13, the first side 210a of the first electrode plate 210 and the second side 220a of the second electrode plate 220 intersect. This case is judged as "not". If it is "not", it is presumed that a displacement of the first electrode plate 210 occurred when the first fixing member 310 was removed. Here, the first side 210a of the first electrode plate 210 and the second side 220a of the second electrode plate 220 intersect at an obtuse angle θ. If the first side 210a of the first electrode plate 210 and the second side 220a of the second electrode plate 220 are considered the long sides of the electrode plates, it is easier to determine whether the first side 210a and the second side 220a intersect or not. Also, it becomes easier to obtain the obtuse angle θ formed by the first side 210a and the second side 220a.

[0057] Furthermore, if a misalignment occurs in the first electrode plate 210, as shown in Figure 12, when the assembly 200 is viewed from a direction perpendicular to the stacking direction Z (here, the short side direction Y), the length of the first electrode plate 210 in the long side direction X will be longer than when no misalignment occurs. Also, when the assembly 200 is viewed from a direction perpendicular to the stacking direction Z (here, the short side direction Y), in addition to the first end face 210b extending in the long side direction X of the first electrode plate 210, a second end face 210c extending in the short side direction Y of the first electrode plate 210 may be observed. In some examples, criteria for determining correctness may include, for example, the length of the first electrode plate 210 in the long side direction X, or whether or not the second end face 210c of the first electrode plate 210 is observed.

[0058] (7) Correction process S70 The correction step S70 includes correcting the position of the first electrode plate 210 if the determination step S60 is determined to be "no". Figure 14 is a schematic diagram illustrating the position correction of the first electrode plate 210. Here, if the determination step S60 is determined to be "no", first the second fixing member 320 is removed from the assembly 200. Next, the second electrode plate 220 is removed from the assembly 200. The removed second electrode plate 220 can be used again as a component of the assembly 200. The second electrode plate 220 may be temporarily held by an electrode plate transfer unit (e.g., an arm) until the second mounting step S30 is performed again.

[0059] Next, the separator 26 covering the first electrode plate 210 is removed. For example, the separator 26 can be removed by stopping the supply of the separator 26 by the roller 110 and scanning the roller 110 in the long side direction X. Alternatively, the separator 26 can be removed by reversing the rotation of the roller 110 to unwind the separator 26. With the separator 26 removed, the first electrode plate 210 is exposed at the top of the assembly 200 (see Figure 14). The position of the first electrode plate 210 is then corrected to the appropriate position. Here, the first electrode plate 210 is lifted by the arm 500 and placed in the appropriate position. That is, the first placement step S10 is performed again. After that, the steps from the first folding step S20 to the determination step S60 are performed as described above. In the determination step S60, if the result is determined to be "positive" (i.e., the state shown in Figure 10), the separator 26 is folded back so as to sandwich the second electrode plate 220. Thereafter, the placement of electrode plates and the folding of the separator 26 can be repeated until the number of electrode plates constituting the laminated electrode body 20 is reached.

[0060] In the correction step S70, the position of the first electrode plate 210 can be corrected according to the calculation result based on the position information of the first electrode plate 210 acquired in the position information acquisition step S50. For example, the correction amount can be calculated based on the obtuse angle θ formed by the first side 210a of the first electrode plate 210 and the second side 220a of the second electrode plate 220.

[0061] Furthermore, if the first placement process S10 to the judgment process S60 are performed again after the correction process S70, the judgment in the judgment process S60 may again result in a "failure." In this case, it is presumed that the cause is a defect in the first fixing member 310 (e.g., wear, foreign matter adhesion, etc.). Therefore, if the judgment in the judgment process S60 results in a "failure" two or more times in a row, a process to replace or repair the first fixing member 310 may be performed.

[0062] Although several manufacturing methods have been described above, these are merely examples. This technology can be implemented in various other forms. The technologies described in the claims include various modifications and changes to the manufacturing methods exemplified above. For example, it is possible to replace parts of the above-described manufacturing methods with other modifications, and it is also possible to add other modifications to the above-described manufacturing methods. Furthermore, if a technical feature is not described as essential, it may be deleted as appropriate.

[0063] In the example of the manufacturing method described above, the case where the first electrode plate 210 is a negative electrode plate 24 and the second electrode plate 220 is a positive electrode plate 22 was explained. However, in some examples, the first electrode plate 210 may be a positive electrode plate 22 and the second electrode plate 220 may be a negative electrode plate 24. Figure 15 is a diagram corresponding to Figure 11 in an example where the first electrode plate 210 is a positive electrode plate 22 and the second electrode plate 220 is a negative electrode plate 24. Figure 16 is a diagram corresponding to Figure 13 in an example where the first electrode plate 210 is a positive electrode plate 22 and the second electrode plate 220 is a negative electrode plate 24. In this case, the area of ​​the second electrode plate 220 may be larger than the area of ​​the first electrode plate 210. Therefore, as shown in Figure 15, the outer edge of the first electrode plate 210 may not be included in the image taken from above of the assembly 200 acquired in the position information acquisition step S50. In this case, positional information of the first electrode plate 210 can be obtained, indicating that the first electrode plate 210 is positioned inside the second electrode plate 220. In this case, in the determination step S60, for example, similar to the determination criteria described above, it can be determined to be "positive" based on the fact that the second side 220a of the second electrode plate 220 and the first side 210a of the first electrode plate 210 do not intersect. Also, as shown in Figure 16, if there is a positional misalignment of the first electrode plate 210, an image taken from above the assembly 200 obtained in the positional information acquisition step S50 may show that the first side 210a of the first electrode plate 210 and the second side 220a of the second electrode plate 220 intersect at an obtuse angle θ. In this case, in the determination step S60, for example, similar to the determination criteria described above, it can be determined to be "negative" based on the fact that the second side 220a of the second electrode plate 220 and the first side 210a of the first electrode plate 210 intersect.

[0064] In the example of the manufacturing method described above, information on the positional relationship between the first electrode plate 210 and the second electrode plate 220 was acquired in the position information acquisition step S50. However, in some examples, information on the positional relationship between the first electrode plate 210 and the third electrode plate 230, which is stacked below the first electrode plate 210 via the separator 26, may be acquired. Figure 17 is a diagram corresponding to Figure 13, showing an example in which the first electrode plate 210 is misaligned after the removal step S40. In Figure 17, both the first electrode plate 210 and the second electrode plate 220 are misaligned when the first fixing member 310 is removed. In this case, while the first electrode plate 210 is misaligned, the first side 210a of the first electrode plate 210 and the second side 220a of the second electrode plate 220 do not intersect in a plan view. Therefore, in the position information acquisition step S50, information on the positional relationship between the first electrode plate 210 and the third electrode plate 230 may be acquired. For example, similar to the example described above, the assembly 200 may be photographed from above by the imaging device 400 using light in a wavelength range that passes through the separator 26. This makes it possible to obtain information that the first side 210a of the first electrode plate 210 and the third side 230a of the third electrode plate 230 intersect at an obtuse angle θ' (see Figure 17). Here, the third side 230a of the third electrode plate 230 is the longer side of the third electrode plate 230. For example, if the first side 210a of the first electrode plate 210 and the third side 230a of the third electrode plate 230 intersect, it can be determined as "no".

[0065] In the example of the manufacturing method described above, in the first placement step S10, the first electrode plate 210 was placed on an assembly 200 in which several electrode plates had already been stacked. However, in some examples, the first electrode plate 210 may be placed on a separator 26 placed on a stacking stage 100. That is, the electrode plate placed in the lowest layer constituting the assembly 200 may be the first electrode plate 210.

[0066] In the example of the manufacturing method described above, the case in which the first electrode plate 210 is a positive electrode plate 22 or a negative electrode plate 24 was explained. However, the first electrode plate 210 may also be an electrode plate (an electrode plate for a so-called bipolar battery) having a positive electrode active material layer containing positive electrode active material on one side of the current collector and a negative electrode active material layer containing negative electrode active material on the other side. Furthermore, the second electrode plate 220 and the third electrode plate 230 may each be electrode plates for a bipolar battery.

[0067] In the drawing illustrating one example of the manufacturing method described above, the separator 26 was folded back along the long side direction X of the assembly 200 (electrode plate). However, in some examples, the separator 26 may be folded back along the short side direction Y.

[0068] As described above, specific embodiments of the technology disclosed herein include those described in the following sections.

[0069] Item 1: A method for manufacturing a stacked electrode body with a zigzag structure, wherein strip-shaped separators are folded back alternately to form a zigzag shape, and electrode plates are alternately sandwiched between the zigzag-shaped separators, A first placement step involves placing the first electrode plate on the separator and holding the first electrode plate down with the first fixing member; Following the first placement step described above, a first folding step is performed in which the separator is folded back so as to sandwich the first electrode plate; Following the first folding step described above, a second placement step is performed in which the second electrode plate is placed on top of the separator so as to overlap the first electrode plate sandwiched between the separators; A position information acquisition step is performed after the second placement step described above, in which the position information of the first electrode plate sandwiched between the separators is acquired; A removal step is performed to remove the first fixing member before the above-mentioned position information acquisition step; A determination step of determining whether the first electrode plate is positioned in a location that satisfies predetermined criteria based on the position information of the first electrode plate obtained above; and A correction step to correct the position of the first electrode plate if the above determination step is determined to be negative; A manufacturing method that includes this. Item 2: The positional information of the first electrode plate includes information on the positional relationship between the first electrode plate and the second electrode plate. The manufacturing method according to item 1, wherein in the determination step described above, it is determined that the case in which a predetermined side of the first electrode plate and a predetermined side of the second electrode plate intersect is not the case. Item 3: In the first placement step described above, the separator is placed on top of the other electrode plates, and the first electrode plate is placed on the separator such that the first electrode plate overlaps the other electrode plates via the separator. The positional information of the first electrode plate includes information on the positional relationship between the first electrode plate and the other electrode plates. The manufacturing method according to item 1 or 2, wherein in the determination step described above, it is determined that the case in which a predetermined side of the first electrode plate and a predetermined side of the other electrode plate intersect is not the case. Item 4: The manufacturing method according to any one of items 1 to 3, wherein in the position information acquisition step, the position information of the first electrode plate is acquired by irradiating the separator with light in a wavelength band that passes through it. Item 5: The manufacturing method according to Item 4, wherein the light in the wavelength range transmitted through the separator is infrared light. Item 6: The manufacturing method according to item 4 or 5, wherein in the position information acquisition step, at least the second electrode plate is photographed from the stacking direction of the second electrode plate and the first electrode plate to acquire information on the positional relationship between the first electrode plate and the second electrode plate. [Explanation of Symbols]

[0070] 1. Energy storage device 10 cases 20. Stacked electrode body 22 Positive plate 22t positive electrode tab 24 Negative plates 24t negative electrode tab 26 Separators 26a 1st page 26b 2nd side 26c1 First fold section 26c2 Second Folding Section 26f flat area 29. Tape to secure the tape 30 Positive terminal 32 Positive electrode current collector 40 Negative terminal 42 Negative electrode current collector 100 stacking stages 110 Laura 200 assembly 210 1st electrode plate 210a First side 210b 1st end face 210c 2nd end face 220 Second electrode plate 220a Second side 230 Third electrode plate 230a Third side 310 First fixing member 310a 1st fixed part 310b 2nd fixed part 320 Second fixing member 320a 3rd fixed part 320b 4th fixed part 400 imaging device 500 Arm

Claims

1. A method for manufacturing a stacked electrode body with a zigzag structure, wherein strip-shaped separators are folded back alternately to form a zigzag shape, and electrode plates are alternately sandwiched between the zigzag-shaped separators, A first placement step involves placing the first electrode plate on the separator and holding the first electrode plate down with the first fixing member; A first folding step is performed after the first placement step, in which the separator is folded back so as to sandwich the first electrode plate; A second placement step is performed, after the first folding step, by placing the second electrode plate on top of the separator so that it overlaps the first electrode plate sandwiched between the separators; A position information acquisition step is performed after the second placement step to acquire the position information of the first electrode plate sandwiched between the separators; Prior to the position information acquisition step, a removal step of removing the first fixing member; A determination step of determining whether the first electrode plate is positioned in a location that satisfies predetermined criteria based on the acquired position information of the first electrode plate; and A correction step to correct the position of the first electrode plate if the determination step is determined to be negative; A manufacturing method that includes this.

2. The positional information of the first electrode plate includes information on the positional relationship between the first electrode plate and the second electrode plate. The manufacturing method according to claim 1, wherein in the determination step, it is determined that the case in which a predetermined side of the first electrode plate and a predetermined side of the second electrode plate intersect is not.

3. In the first placement step, the separator is placed on top of the other electrode plates, and the first electrode plate is placed on the separator such that the first electrode plate overlaps the other electrode plates via the separator. The positional information of the first electrode plate includes information on the positional relationship between the first electrode plate and the other electrode plates. The manufacturing method according to claim 1, wherein in the determination step, it is determined that the case in which a predetermined side of the first electrode plate and a predetermined side of the other electrode plate intersect is not.

4. The manufacturing method according to any one of claims 1 to 3, wherein in the position information acquisition step, the position information of the first electrode plate is acquired by irradiating it with light in a wavelength band that passes through the separator.

5. The manufacturing method according to claim 4, wherein the light in the wavelength band transmitted through the separator is infrared light.

6. The manufacturing method according to claim 4, wherein in the position information acquisition step, at least the second electrode plate is photographed from the stacking direction of the second electrode plate and the first electrode plate to acquire information on the positional relationship between the first electrode plate and the second electrode plate.

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