JP2015115097A - Manufacturing method of electrode assembly, power storage device, and manufacturing apparatus for electrode assembly - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of an electrode assembly capable of reducing weights of cathodes and anodes and a capacity variation between the cathodes and the anodes in the entire electrode assembly.SOLUTION: The manufacturing method of the electrode assembly includes: sorting each of a plurality of cathodes and anodes into a plurality of cathode groups and anode groups which are set on the basis of weights; alternately extracting cathodes and anodes from the cathode groups of a minimum weight to a (m)th weight and anode groups of a minimum weight to a (m)th weight and stacking the extracted cathodes and anodes to form a plurality of first semi-laminates; alternately extracting cathodes and anodes from the cathode groups of a (m+1)th weight to a maximum (n)th weight and the anode groups of a (m+1)th weight to a maximum (n)th weight, and stacking the extracted cathodes and anodes to form a plurality of second semi-laminates; and forming the electrode assembly by stacking the first semi-laminates and the second semi-laminates in such a manner that a total weight of one first semi-laminate and one second semi-laminate is settled within an allowable range defining a target value as a reference and becomes heavy gradually in a direction of lamination.

Description

  The present invention relates to an electrode assembly manufacturing method, a power storage device, and an electrode assembly manufacturing apparatus.

  A power storage device including an electrode assembly configured by a positive electrode and a negative electrode is known. The electrode assembly is manufactured by laminating a rectangular positive electrode plate and a negative electrode plate via a separator (hereinafter, the positive electrode and the negative electrode are also collectively referred to as “electrode plate”). In general, the electrode plate used in the electrode assembly is manufactured as a large plate from which a plurality of single plates can be collected, and the large plates are collectively cut to form a plurality of single plates. Since it is extremely difficult to prevent the weight distribution of the active material from being varied depending on the portion of the large plate, the veneers thus formed have different weights.

  Therefore, when the electrode assembly is manufactured by alternately laminating single plates with different polarities using this single plate group, the weight of the positive electrode or the negative electrode varies depending on which part of the single plate is used. There is. For example, when an electrode assembly is manufactured by combining a positive electrode with the largest manufacturing tolerance, a negative electrode with a minimum, and a separator, the capacity balance between the positive electrode and the negative electrode is lost, and there are problems such as deposition of metal components and overcharge. It is thought that it will occur.

  In order to solve such a problem, for example, in Patent Document 1 (Japanese Patent Laid-Open No. 11-154531), the weight of a single plate is measured and subjected to weight selection, and the total weight of the single plate constituting the electrode assembly. Discloses a method of combining the single plates so that they fall within a predetermined range.

Japanese Patent Laid-Open No. 11-154631

  However, although the above-described conventional manufacturing method can reduce the weight variation of the entire electrode assembly, when attention is paid to the electrode plates adjacent to each other, a portion having a difference in capacitance may occur. If there is such a portion in the electrode assembly, SOC (State Of Charge) unevenness may occur. For example, the life of the power storage device may be shortened.

  Therefore, an object of the present invention is to reduce the weight variation between the positive electrode and the negative electrode in the whole electrode assembly and to reduce the capacity variation between the positive electrode and the negative electrode when manufacturing the electrode assembly. An object of the present invention is to provide a three-dimensional manufacturing method and an electrode assembly manufacturing apparatus. Another object of the present invention is to provide a power storage device including an electrode assembly that can reduce the weight variation between the positive electrode and the negative electrode in the entire electrode assembly and can reduce the capacity variation between the positive electrode and the negative electrode.

A method of manufacturing an electrode assembly according to an aspect of the present invention includes a sorting step of sorting each of a plurality of positive electrodes and negative electrodes into a plurality of positive electrode groups and a negative electrode group set based on weight, a plurality of positive electrode groups, when arranged in each order based Fukyokugun weight, from the negative electrode unit from the positive electrode group and weight smallest first from the smallest first weight until the weight m _P th until the weight m _N th, A first lamination step of alternately taking out the positive electrode and the negative electrode, and alternately stacking the positive electrode and the negative electrode so that the respective weights of the positive electrode and the negative electrode gradually increase or decrease, thereby forming a plurality of first semi-laminates. When taken out from the negative electrode unit from the positive electrode group and m _n + 1-th +1 th weight m _P to the most significant n _P th until the weight is greatest n _n th weight, the positive and negative electrodes alternately A second laminating step of alternately stacking the positive and negative electrodes so that the respective weights of the positive electrode and the negative electrode gradually increase or decrease, thereby forming a plurality of second semi-laminates; and a plurality of first semi-laminates Of the body and the plurality of second semi-laminates so that the combined weight of one first semi-laminate and one second semi-laminate is within an allowable range based on the target value. A combination step of selecting a combination of the first semi-laminate and one second semi-laminate, and the first and second semi-laminates selected in the combination step, the positive electrode and the negative electrode And a third stacking step of forming the electrode assembly by stacking so that the weights of each of the electrodes gradually increase or decrease along the stacking direction.

An apparatus for manufacturing an electrode assembly according to an aspect of the present invention includes a sorting unit that classifies each of a plurality of positive electrodes and negative electrodes into a plurality of positive electrode groups and a negative electrode group set based on weight, a plurality of positive electrode groups, when arranged in each order based Fukyokugun weight, from the negative electrode unit from the positive electrode group and weight smallest first from the smallest first weight until the weight m _P th until the weight m _N th, A first stacked unit that alternately takes out the positive electrode and the negative electrode, and alternately stacks the positive electrode and the negative electrode so that the respective weights of the positive electrode and the negative electrode gradually increase or decrease, thereby forming a plurality of first semi-stacked bodies. If, from the negative electrode unit from the positive electrode group and m _n +1 th from weight m _P +1 th to the most significant n _P th until the weight is greatest n _n th weight, removed positive and negative electrodes alternately positive And a plurality of first semi-laminates, wherein a plurality of first semi-laminates are formed by alternately stacking positive and negative electrodes so that the respective weights of the negative and negative electrodes gradually increase or decrease. And the first semi-laminate so that the combined weight of the first semi-laminate and the second semi-laminate is within an allowable range based on the target value. A combination part for selecting a combination of one semi-laminate and one second semi-laminate, one first semi-laminate and one second semi-laminate selected by the combination part, and And a third laminated portion that forms an electrode assembly by being stacked so that the respective weights gradually increase or decrease along the stacking direction.

  In these manufacturing methods and manufacturing apparatuses, after forming a plurality of first and second semi-laminates, the combined weight of the first and second semi-laminates is based on the target value. The electrode assembly is formed by stacking them so as to be within the allowable range. Thereby, it is possible to easily set the variation in the overall weight of the electrode assembly within a predetermined range. In addition, the positive and negative electrodes sorted into the positive electrode group and the negative electrode group set based on the weight are stacked so that the weight of each of the positive electrode and the negative electrode gradually increases or decreases, so that the adjacent positive electrode and The weight difference from the negative electrode (weight difference of the active material) can be easily set within a certain range. That is, in the adjacent positive electrode and negative electrode, the ratio (N / P) of the negative electrode capacity N to the positive electrode capacity P is easily set within a predetermined range.

Here, the order m _P in the positive electrode group and the order m _{N in the} negative electrode group may be different from each other. For example, the positive electrode group may be up to the fourth and the negative electrode group may be up to the fifth. Similarly, the weight of the order n _N in weight of the order n _P and Fukyokugun in group of electrodes may be different from each other.

  In one embodiment, the electrode assembly manufacturing method includes a plurality of first semi-stacks in the first stacking step, in which the positive and negative electrodes are alternately stacked so that the weights of the positive and negative electrodes gradually increase. In the second lamination step, the positive electrode and the negative electrode are alternately stacked so that the respective weights of the positive electrode and the negative electrode are gradually increased to form a plurality of second semi-laminates. The first semi-laminate and the second semi-laminate selected in the combining step are composed of an electrode on the stacking end side in the first semi-laminate and an electrode on the stacking start side in the second semi-laminate. The electrode assembly may be formed by stacking so as to face each other.

  Moreover, in one embodiment, in the electrode assembly manufacturing apparatus, the first stacked unit alternately stacks the positive electrode and the negative electrode so that the respective weights of the positive electrode and the negative electrode gradually increase, thereby providing a plurality of first semi-stacks. And forming a plurality of second semi-stacks by alternately stacking positive and negative electrodes so that the respective weights of the positive and negative electrodes gradually increase. The first semi-laminate and the second semi-laminate selected in the combination part are composed of an electrode on the stacking end side in the first semi-laminate and an electrode on the stacking start side in the second semi-laminate. The electrode assembly may be formed by stacking so as to face each other.

  In these manufacturing methods and manufacturing apparatuses, the weights of the positive electrode and the negative electrode are stacked by stacking the electrodes on the stacking end side in the first semi-laminate and the electrodes on the stacking start side in the second semi-laminate so as to face each other. It is possible to form an electrode assembly that gradually becomes lighter or heavier. The electrode assembly can be formed by a simple operation in which the electrodes on the stacking end side in the first semi-stacked body and the electrodes on the stacking start side in the second semi-stacked body are stacked facing each other.

  In one embodiment, the method for manufacturing an electrode assembly may be such that the polarity of the electrode on the stacking end side in the first semi-laminate and the polarity of the electrode on the stacking start side in the second semi-laminate are different from each other. Good.

  Further, in one embodiment, the electrode assembly manufacturing apparatus may be configured such that the polarity of the electrode on the stacking end side in the first semi-laminate and the polarity of the electrode on the stacking start side in the second semi-laminate are different from each other. Good.

  In these electrode assembly manufacturing method and manufacturing apparatus, if the electrode on the stacking end side in the first semi-stacked body is a positive electrode, the electrode on the stacking start side in the second semi-stacked body is used as the negative electrode, and the first semi-stacked body If the electrode on the stacking end side in is a negative electrode, the electrode on the stacking start side in the second semi-stacked body is the positive electrode. Thereby, the electrode assembly by which the positive electrode and the negative electrode were laminated | stacked alternately can be formed.

  In one embodiment, the electrode assembly manufacturing method includes a plurality of first semi-stacks in the first stacking step, in which the positive and negative electrodes are alternately stacked so that the weights of the positive and negative electrodes gradually increase. In the second lamination step, the positive electrode and the negative electrode are alternately stacked so that the respective weights of the positive electrode and the negative electrode are gradually reduced to form a plurality of second semi-laminates. In the third lamination step, The first semi-laminate and the second semi-laminate selected in the combining step are configured such that an electrode on the stacking end side in the first semi-laminate and an electrode on the stacking end side in the second semi-laminate are The electrode assembly may be formed by stacking so as to face each other.

  In one embodiment, the electrode assembly manufacturing apparatus includes a plurality of first half-stacks in which the positive electrode and the negative electrode are alternately stacked so that the weight of each of the positive electrode and the negative electrode gradually increases in the first stack unit. And forming a plurality of second semi-stacks by alternately stacking the positive and negative electrodes so that the respective weights of the positive and negative electrodes are gradually reduced. The first semi-laminate and the second semi-laminate selected by the combination unit are arranged such that an electrode on the stacking end side in the first semi-laminate and an electrode on the stacking end side in the second semi-laminate are The electrode assembly may be formed by stacking so as to face each other.

  In these electrode assembly manufacturing methods and manufacturing apparatuses, the respective weights of the positive electrode and the negative electrode are obtained by stacking the electrodes so that the electrodes on the stacking side of the first semi-laminate and the second semi-laminate are opposed to each other. An electrode assembly can be formed that gradually becomes lighter or heavier. The first semi-laminate and the second semi-laminate can form an electrode assembly by a simple operation of stacking the electrodes on the side stacked last so as to face each other.

  Further, in one embodiment, the electrode assembly manufacturing method may be configured such that the polarity of the electrode at the end of stacking in the first semi-stack and the polarity of the electrode at the end of stacking in the second semi-stack are different from each other. Good.

  In one embodiment, the electrode assembly manufacturing apparatus may be configured such that the polarity of the electrode at the end of stacking in the first semi-stack and the polarity of the electrode at the end of stacking in the second semi-stack are different from each other. Good.

  In these electrode assembly manufacturing methods and manufacturing apparatuses, if the electrode on the stacking end side in the first semi-stacked body is a positive electrode, the electrode on the stacking end side in the second semi-stacked body is used as the negative electrode, and the first semi-stacked body If the electrode on the stacking end side in is a negative electrode, the electrode on the stacking end side in the second semi-stacked body is the positive electrode. Thereby, the electrode assembly by which the positive electrode and the negative electrode were laminated | stacked alternately can be formed.

  Moreover, in one Embodiment, it can also be set as an electrical storage apparatus provided with a case and the electrode assembly accommodated in the case and manufactured by said manufacturing method.

  The power storage device having this configuration can include an electrode assembly in which the variation in weight between the positive electrode and the negative electrode in the entire electrode assembly is reduced and the variation in capacity between the positive electrode and the negative electrode is reduced.

  According to the present invention, when manufacturing the electrode assembly, it is possible to reduce the weight variation between the positive electrode and the negative electrode in the entire electrode assembly, and to reduce the capacity variation between the positive electrode and the negative electrode. In addition, it is possible to provide an electrode assembly in which variation in weight between the positive electrode and the negative electrode in the entire electrode assembly is reduced and capacity variation between the positive electrode and the negative electrode is reduced.

It is sectional drawing which shows typically an electrical storage apparatus provided with the electrode assembly manufactured by the manufacturing method of the electrode assembly which concerns on one Embodiment. It is sectional drawing of the electrical storage apparatus along the II-II line | wire of FIG. It is a flowchart which shows each process in the manufacturing method of the electrode assembly which concerns on one Embodiment. It is a figure for demonstrating a sorting process. It is a figure for demonstrating the positive electrode group and negative electrode group taken out in a 1st lamination process and a 2nd lamination process, respectively. It is a figure for demonstrating a 1st lamination process. It is a figure for demonstrating a 2nd lamination process. It is a figure for demonstrating a combination process. It is a figure for demonstrating a 3rd lamination process. It is a figure which shows schematic structure of the manufacturing apparatus of the electrode assembly which concerns on one Embodiment.

  Hereinafter, an electrode assembly manufacturing method and a manufacturing apparatus according to an embodiment will be described with reference to the drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted. The dimensional ratios in the drawings do not necessarily match those described.

  First, a power storage device including an electrode assembly manufactured by an electrode assembly manufacturing method according to an embodiment will be described. Power storage device 200 is a nonaqueous electrolyte secondary battery such as a lithium ion secondary battery. The power storage device 200 is not limited to a secondary battery, and may be an electric double layer capacitor, for example.

  A power storage device 200 shown in FIGS. 1 and 2 includes a case 10 and an electrode assembly 20 accommodated in the case 10. Case 10 may be formed, for example from metals, such as aluminum system metal or stainless steel. The electrode assembly 20 includes a positive electrode 30, a negative electrode 40, and a separator 50 disposed between the positive electrode 30 and the negative electrode 40. The electrode assembly 20 is manufactured by a manufacturing method described in detail later.

  The positive electrode 30 and the negative electrode 40 are formed in a sheet shape. In the power storage device 200 of the present embodiment, the separator 50 is formed in a sheet shape. The plurality of positive electrodes 30 and the plurality of negative electrodes 40 are alternately stacked via separators 50 in the Y-axis direction. The separator 50 may be formed in a bag shape. In this case, the positive electrode 30 is accommodated in the bag-shaped separator 50. The case 10 can be filled with an electrolytic solution 60. Examples of the electrolytic solution 60 include organic solvent-based or non-aqueous electrolytic solutions.

  The positive electrode 30 includes a positive metal foil 30B and a positive electrode active material layer 30C provided on the positive metal foil 30B. The positive electrode active material layer 30C can be provided on both surfaces of the positive electrode metal foil 30B. The positive electrode metal foil 30B is, for example, an aluminum foil. The positive electrode active material layer 30C may include a positive electrode active material, a conductive additive, and a binder. Examples of the positive electrode active material include composite oxide, metallic lithium, and sulfur. The composite oxide includes at least one of manganese, nickel, cobalt, and aluminum and lithium.

  The positive electrode 30 has a tab 30A formed at the edge. The tab 30A does not hold the positive electrode active material. The positive electrode 30 is connected to the conductive member 32 via the tab 30A. The conductive member 32 is connected to the positive terminal 34. The positive electrode terminal 34 may be attached to the case 10 via an insulating ring 36.

  The negative electrode 40 includes a negative electrode metal foil 40B and a negative electrode active material layer 40C provided on the negative electrode metal foil 40B. The negative electrode active material layer 40C can be provided on both surfaces of the negative electrode metal foil 40B. The negative electrode metal foil 40B is, for example, a copper foil. The negative electrode active material layer 40C may include a negative electrode active material and a binder. Examples of the negative electrode active material include graphite, highly oriented graphite, mesocarbon microbeads, carbon such as hard carbon and soft carbon, alkali metals such as lithium and sodium, metal compounds, and SiOx (0.5 ≦ x ≦ 1. 5) and other metal oxides, boron-added carbon and the like.

  The negative electrode 40 has a tab 40A formed at the edge. The negative electrode active material is not held on the tab 40A. The negative electrode 40 is connected to the conductive member 42 via the tab 40A. The conductive member 42 is connected to the negative terminal 44. The negative electrode terminal 44 may be attached to the case 10 via the insulating ring 46.

  Examples of the separator 50 include a porous film made of a polyolefin-based resin such as polyethylene (PE) and polypropylene (PP), a woven fabric or a non-woven fabric made of polypropylene, polyethylene terephthalate (PET), methylcellulose, and the like.

  The power storage device 200 of this embodiment further includes a first metal plate 12, a second metal plate 14, and an insulating member 16. A second metal plate 14 is disposed between the case 10 and the electrode assembly 20. The second metal plate 14 is, for example, a single plate member, but may be a plurality of stacked metal foils. The second metal plate 14 is not provided with an active material layer. The second metal plate 14 is an uncoated electrode for safety measures.

  The first metal plate 12 is disposed between the case 10 and the second metal plate 14. The first metal plate 12 is, for example, a single plate member, but may be a plurality of stacked metal foils. The first metal plate 12 is not provided with an active material layer. The first metal plate 12 is an uncoated electrode for safety measures. The first metal plate 12 is accommodated in a bag-like insulating member 16. The insulating member 16 may be formed as a resin layer such as a resin sheet.

  In the power storage device 200 of this embodiment, the first metal plate 12, the insulating member 16, and the second metal plate 14 constitute a safety measure short-circuit unit 65. The short circuit unit 65 for safety measures is applied to the first metal plate 12 and the second metal plate 14 which are uncoated electrodes when a force for crushing the power storage device 200 is applied or when a nail or the like is stuck in the power storage device 200. By passing a short circuit current between the positive electrode 30 and the negative electrode 40 coated with the active material, thermal runaway is prevented.

  FIG. 3 is a flowchart showing each step in the method of manufacturing the electrode assembly 20 according to the embodiment. As shown in FIG. 3, the manufacturing method of the electrode assembly 20 according to an embodiment includes a sorting process S1, a first stacking process S2, a second stacking process S3, a combination process S4, and a third stacking process S5. And.

In the method of manufacturing the electrode assembly 20, first, sorting each for each of the plurality of positive electrodes 30 and negative electrodes 40, the negative electrode unit having a positive electrode group and n _N groups n _P group that is set based on the weight (sorting step S1) . For example, in the manufacturing method of the electrode assembly 20 in one embodiment, as shown in FIG. 4, a plurality of positive electrodes 30 of the distribution of weight _{W P} is _{W 0 ≦ W P <W 8} , the weight _{W P} of the positive electrode 30 based on the set of eight group of electrodes _{(P 1: W 0 ≦ W} P <W 1, P 2: W 1 ≦ W P <W 2, P 3: W 2 ≦ W P <W 3, P 4: W _{3 ≦ W P <W 4,} P 5: W 4 ≦ W P <W 5, P 6: W 5 ≦ W P <W 6, P 7: W 6 ≦ W P <W 7, P 8: W 7 ≦ ₉ negative electrode groups (N ₁₎ set based on the weight W _N of the negative electrode 40 for a plurality of negative electrodes 40 that are classified into W _P <W ₈ ) and the distribution of the weight W _N is W ₀ ≦ W _N <W _{9. : W 0 ≦ W N <W} 1, N 2: W 1 ≦ W N <W 2, N 3: W 2 ≦ W N <W 3, N 4: W 3 ≦ W N <W 4, N 5 _{: W 4 ≦ W N <W} 5, N 6: W 5 ≦ W N <W 6, N 7: W 6 ≦ W N <W 7, N 8: W 7 ≦ W N <W 8, N 9: W ₈ ≦ W _N <W ₉ ).

Further, in the sorting step S1, the ratio of the capacity N of the negative electrode 40 to the capacity P of the positive electrode 30 in the adjacent positive electrode 30 and the negative electrode 40 when alternately stacking in the first stacking step S2 and the second stacking step S3 described later ( A positive electrode group (P _{1 to} P ₈ ) and a negative electrode group (N _{1 to} N ₉ ) are set such that (N / P) is a predetermined value.

Hereinafter, extracts a plurality of positive electrode group and Fukyokugun in each so that a large group of small groups of weight were ordered, to the positive electrode unit weight is m _P th from the smallest first positive group weight In addition, a group obtained by extracting from the first negative electrode group having the smallest weight to the m _Nth negative electrode group having the weight is defined as a first group G _1, and the n _P th largest _one from the m _P + _1st positive electrode group is defined as the first group G ₁ . It extracts a to group of electrodes, illustrating a group extracted from m n ₊₁ th negative group to heaviest big n _n-th negative group as the second group G _2. For example, in the manufacturing method of the electrode assembly 20 of one embodiment, as shown in FIG. 5, the first positive electrode group P ₁ and the negative electrode group N ₁ having the smallest weight to the fourth positive electrode group P ₄ and the negative electrode group N ₄ and the first group G ₁ extracted respectively up, extracts the heaviest big eighth group of electrodes P ₈ from the fifth group of electrodes P _5, Do heaviest size from 5 th Fukyokugun N ₅ 9 th the second group _{G 2} obtained by extracting Fukyokugun _{N 9.}

Then, stacked alternately from the first positive electrode unit and negative electrode unit group G ₁ is taken out of the positive electrode 30 and negative electrode 40, the positive electrode 30 and the negative electrode 40 so that the respective weight of the positive electrode 30 and the negative electrode 40 is gradually heavier alternately Then, a plurality of first semi-stacked bodies 20A are formed (first stacking step S2). For example, in the manufacturing method of the electrode assembly 20 of one embodiment, as shown in FIG. 6, the negative electrode group N ₁ , the positive electrode group P ₁ , the negative electrode group N ₂ , the positive electrode group P ₂ , the negative electrode group N ₃ , and the positive electrode group P _{3. The} negative electrode 40 and the positive electrode 30 are taken out alternately in the order of the negative electrode group N ₄ and the positive electrode group P ₄ . Further, a separator 50 prepared separately is taken out while the negative electrode 40 and the positive electrode 30 are taken out. As a result, a plurality of first semi-stacked bodies 20A that are gradually heavier as the weights W _P and W _N of the positive electrode 30 and the negative electrode 40 are stacked are formed.

Then, stacked alternately from the second positive electrode unit and negative electrode unit group G ₂ is taken out of the positive electrode 30 and negative electrode 40, the positive electrode 30 and the negative electrode 40 so that the respective weight of the positive electrode 30 and the negative electrode 40 is gradually heavier alternately Then, a plurality of second semi-stacked bodies 20B are formed (second stacking step S3). For example, in the manufacturing method of the electrode assembly 20 of one embodiment, as shown in FIG. 7, the negative electrode group N ₅ , the positive electrode group P ₅ , the negative electrode group N ₆ , the positive electrode group P ₆ , the negative electrode group N ₇ , and the positive electrode group P _{7. The} positive electrode 30 and the negative electrode 40 are taken out alternately in the order of the negative electrode group N ₈ , the positive electrode group P ₈ , and the negative electrode group N ₉ . Also in the second stacking step S <b> 3, a separately prepared separator 50 is disposed between the negative electrode 40 and the positive electrode 30. As a result, a plurality of second half-stacked bodies 20B that are gradually heavier as the weights of the positive electrode 30 and the negative electrode 40 are stacked are formed.

Next, from among the plurality of first half-layers 20A _{1 to} 20A _n and the plurality of second half-layers 20B _{1 to} 20B _n , one first half-layer body 20A and one second half-layer body 20B weight W _T of the combined is such that within an allowable range relative to the target value W _D, selects a combination of one first half stack 20A and one second half-stack 20B (combining step S4 ). For example, in the manufacturing method of the electrode assembly 20 in one embodiment, as shown in FIG. 8, one first half stack 20A and one second half-stack 20B and weight W _T is the target value W of the combined A combination of one first half-layer 20A ₃ and one second half-layer 20B ₂ is selected so that it falls within a predetermined range with reference to _D , or one first half-layer 20A _{n -1} and one second semi-laminate 20B ₄ can be selected.

Next, the electrode assembly 20 is formed by stacking one first half-layered body 20A and one second half-layered body 20B selected in the combination step S4 so as to gradually become heavier along the stacking direction. (Third stacking step S5). For example, in one method of manufacturing the embodiment of the electrode assembly 20, as shown in FIG. 9, loading end side of the electrode in the first half stack 20A ₃ one selected in combination step S4 _(P 4 (30) ) And the electrodes on the stacking start side (N ₅ (40)) in the second half-stacked body 20B ₂ selected in the combination step S4 are stacked so as to face each other with the separator 50 therebetween. 20 can be formed. That is, the positive electrode 30 taken out from the positive electrode group P ₄ in the first half-stacked body 20 A ₃ and the negative electrode 40 taken out from the negative electrode group N ₅ in the second half-stacked body 20 A ₃ are opposed to each other through the separator 50. The electrode assembly 20 can be formed by stacking.

  As described above, the electrode assembly 20 as shown in FIG. 2 is manufactured through the sorting step S1 to the third stacking step S5.

  Next, an electrode assembly manufacturing apparatus 70 for manufacturing the electrode assembly 20 by the above-described electrode assembly manufacturing method will be described. FIG. 10 is a diagram illustrating a schematic configuration of an electrode assembly manufacturing apparatus 70 according to an embodiment. As shown in FIG. 10, the manufacturing apparatus 70 for the electrode assembly 20 includes a control unit 90, sorting units 71 and 81, a first stacking unit 101, a second stacking unit 111, a third stacking unit 121, It has.

  The control unit 90 is a part that controls various operations in the manufacturing apparatus 70 of the electrode assembly 20, and includes a central processing unit (CPU), a read only memory (ROM), a random access memory (RAM), and a hard disk. As shown in FIG. 10, the control unit 90 mainly has a combination unit 93. The functions executed by such a conceptual part are executed under the control of a CPU or the like.

Sorting unit 71, a plurality of the positive electrode 30 is a portion to sort the eight group of electrodes _P 1 to P _8, which is set based upon the weight _{W P.} Specifically, the transport device 72 takes out one positive electrode 30 from a stocker 73 in which a plurality of positive electrodes 30 are stored. The transport device 72 is arranged so as to be movable in the front-rear (depth) left-right direction shown in FIG. 10 along the rail 79, for example, and sucks and transports the positive electrode 30. The stocker 73 has a built-in weight scale, and calculates the weight of the positive electrode 30 taken out by the transfer device 72 from the change in weight when the positive electrode 30 is taken out by the transfer device 72.

At positions adjacent to the stocker 73, stockers 75 respectively corresponding to the _eight positive electrode groups P _{1 to} P ₈ are arranged. Although not shown in FIG. 10, for example, eight stockers 75 are arranged in the depth direction. The transfer device 72 stores the extracted positive electrode 30 in the stocker 75 of the positive electrode group corresponding to the weight of the positive electrode 30 based on the weight calculated in the previous step.

The sorting unit 81 is a part that sorts the plurality of negative electrodes 40 into nine negative electrode groups N _{1 to} N ₉ set based on the weight W _N. Specifically, the conveyance device 82 takes out one negative electrode 40 from a stocker 83 in which a plurality of negative electrodes 40 are accommodated. The conveyance device 82 is arranged to be movable in the front-rear and left-right directions shown in FIG. 10, and adsorbs and conveys the negative electrode 40. The stocker 83 has a built-in weight scale, and calculates the weight of the negative electrode 40 taken out by the transport device 82 from the change in weight when the negative electrode 40 is taken out by the transport device 82.

At positions adjacent to the stocker 83, stockers 85 respectively corresponding to the _nine negative electrode groups N _{1 to} N ₉ are arranged. Although not shown in FIG. 10, for example, nine stockers 85 are arranged in the depth direction. The transport device 82 stores the extracted negative electrode 40 in the negative electrode group stocker 85 corresponding to the weight of the negative electrode based on the weight calculated in the previous step.

The first stack unit 101, the eight group of electrodes P ₁ to P ₈ the most weight at the time of arranging the respective order so that a large group of small group of weight small first from group of electrodes P ₁ 4 th a group of electrodes P _4, 9 one Fukyokugun N ₁ to N of the most weight at the time of arranging the respective order as a major group ₉ from a small group of weight small first Fukyokugun N ₁ from the fourth negative taken from among the group N ₄ the positive electrode 30 and the negative electrode 40 are alternately stacked a positive electrode 30 and the negative electrode 40 so that the respective weight of the positive electrode 30 and the negative electrode 40 is gradually heavier alternately a plurality of first half stack It is a part forming the body 20A.

For example, the transport device 77 takes out the negative electrode 40 from the stocker 85 of the negative electrode group N ₁ , performs alignment with the alignment unit 104 disposed adjacent to the stocker 85, and then adjacent to the alignment unit 104. It is placed on the placed stocker 105. The conveyance device 77 adsorbs and conveys the negative electrode 40 (positive electrode 30). The alignment by the alignment unit 104 adjusts the adsorption position with respect to the negative electrode 40. Thereby, the negative electrode 40 can be placed at a predetermined position of the stocker 105. Next, the transport device 77 takes out the separator 50 from a group of separators (not shown), performs the same alignment as that of the negative electrode 40, and then places the separator 50 on the stocker 105. Next, the conveying device 77, a positive electrode 30 was taken out from the stocker 75 of group of electrodes P _1, after the positioning by the positioning unit 103 disposed adjacent to the stocker 75, adjacent to the positioning unit 103 Placed on the stocker 105 arranged in the above manner. That is, the transport device 77 stacks the positive electrode 30 on the negative electrode 40 and the separator 50 previously placed on the stocker 105.

As described above, the negative electrode group N ₁ , the separator group, the positive electrode group P ₁ , the separator group, the negative electrode group N ₂ , the separator group, the positive electrode group P ₂ , the separator group, the negative electrode group N ₃ , the separator group, the positive electrode group P ₃ , The negative electrode 40, the separator 50, and the positive electrode 30 are taken out from the respective groups in the order of the separator group, the negative electrode group N ₄ , the separator group, and the positive electrode group P ₄ , and placed on the stocker 105. As a result, a plurality of first semi-laminates 20A are formed that are stacked so that the weights of the positive electrode 30 and the negative electrode 40 gradually increase. The plurality of first semi-laminates 20A are arranged in the depth direction of FIG.

The second laminate unit 111, the heaviest of eight group of electrodes P ₁ to P ₈ a weight upon each so that a large group of small groups of weight were ordered magnitude fifth group of electrodes P ₅ 8th positive electrode group P ₈ and nine negative electrode groups N _{1 to} N ₉ are arranged in order from a group having a smaller weight to a group having a larger weight. _The positive electrode 30 and the negative electrode 40 are alternately taken out of the _ninth negative electrode group N ₉ having the largest weight from _5, and the positive electrode 30 and the negative electrode 40 are alternately arranged so that the weights of the positive electrode 30 and the negative electrode 40 gradually increase. This is a portion that is stacked to form a plurality of second semi-stacked bodies 20B.

For example, a specific method for forming the second half-stacked body 20B is the same as the method for forming the first half-layered body 20A, and thus detailed description thereof is omitted here. That is, negative electrode group N ₅ , separator group, positive electrode group P ₅ , separator group, negative electrode group N ₆ , separator group, positive electrode group P ₆ , separator group, negative electrode group N ₇ , separator group, positive electrode group P ₇ , separator group, The negative electrode 40, the separator 50, and the positive electrode 30 are taken out from the respective groups in the order of the negative electrode group N ₈ , the separator group, the positive electrode group P ₈ , the separator group, and the negative electrode group N ₉ , and placed on the stocker 105. As a result, a plurality of second half-stacked bodies 20B are formed that are stacked so that the weights of the positive electrode 30 and the negative electrode 40 gradually increase. The plurality of second semi-stacked bodies 20B are arranged in the depth direction of FIG. Note that the stocker 105 may not be disposed in forming the first semi-laminate 20A and the second semi-laminate 20B.

The combination unit 93 has a weight W _T that is obtained by combining one first half-layer 20A and one second half-layer 20B from the plurality of first half-layers 20A and the plurality of second half-layers 20B. There so falls within an allowable range relative to the target value W _D, a part for selecting a combination of one first half stack 20A and one second half-stack 20B.

Specifically, in the first stacked unit 101 and the second stacked unit 111, the total weight of the positive electrode 30 and the negative electrode 40 is stored in the storage unit when the first half stacked unit 20A and the second semi stacked unit 20B are formed. since it is stored in, the combination unit 93, based on the information, based on the weight W _T is the target value W _D to the combination of the one first half stack 20A and one second half-stack 20B The combination of one first half-laminate 20A and one second half-laminate 20B is selected so that it falls within the allowable range. The combination unit 93 may store the selection information thus selected in the storage unit.

The third stacked unit 121 is formed by stacking one first half-stacked body 20A and one second half-layered body 20B selected in the combination unit 93 so as to gradually become heavier along the stacking direction. 20 is a portion that forms 20. In the third multilayer portion 121, as shown in FIG. 9, the loading end side of the electrode in the first half stack 20A ₃ one _(P 4 _(30)), begins loading in one of the second half stack 20B ₂ The electrode assembly 20 is formed by stacking the side (N ₅ (40)) electrodes so as to face each other via the separator 50. For example, the third stacked unit 121 holds the second semi-stacked body 20 </ b> B formed in one stocker 105 with a chuck (not shown) and the like, and the first semi-stacked layer formed in the one stocker 105. The chuck is released in a state where it is moved above the body 20A and aligned with the first semi-stacked body 20A. Thus, by stacking and loading end of the side electrode in the first half stack 20A ₃ one, and a loading start-side electrode in the second half stack 20B ₂ one, so as to be opposed to each other via the separator 50 An electrode assembly 20 can be formed.

In the manufacturing method and the manufacturing apparatus 70 for the electrode assembly 20 according to the above-described embodiment, the first semi-laminated body 20A and the second semi-laminated body are formed after a plurality of the first semi-laminated body 20A and the second semi-laminated body 20B are formed. weight W _T of the combined and 20B is selected to be within the allowable range based on the target value W _D, are stacked them. Thereby, the dispersion | variation in the whole weight as the electrode assembly 20 can be easily set to the range within a predetermined. Moreover, the positive electrode 30 and the negative electrode 40 classified into the positive electrode group (P _{1 to} P ₈ ) and the negative electrode group (N _{1 to} N ₉ ) respectively set based on the weights W _P and W _N are used. Since the positive electrodes 30 and the negative electrodes 40 are alternately stacked so that the respective weights W _P and W _N gradually increase, the weight difference between the adjacent positive electrodes 30 and the negative electrodes 40 can be easily set within a certain range. That is, in the adjacent positive electrode and negative electrode, the ratio (N / P) of the capacity N of the negative electrode 40 to the capacity P of the positive electrode 30 can be easily set within a predetermined range.

Here, in the sorting process S1, the ratio (N / P) of the capacity N of the negative electrode 40 to the capacity P of the adjacent positive electrodes 30 is a predetermined value when alternately stacking in the first stacking process S2 and the second stacking process S3. The positive electrode group (P _{1 to} P ₈ ) and the negative electrode group (N _{1 to} N ₉ ) can be set. Specifically, the weights of the positive electrode group and the negative electrode group are set in consideration of the positive electrode and the negative electrode that are arranged adjacent to each other. For example, considering that the positive electrode 30 and the negative electrode 40 belonging to the positive electrode group P ₁ and the negative electrode group N ₁ are disposed adjacent to each other, the weight of the positive electrode 30 belonging to the positive electrode group P ₁ and the negative electrode group The weight of the negative electrode 40 that will belong to N ₁ is set. By setting the positive electrode group (P _{1 to} P ₈ ) and the negative electrode group (N _{1 to} N ₉ ), the ratio of the negative electrode capacity N to the positive electrode capacity P (N / P) is a predetermined value. Therefore, the electrode assembly 20 having excellent performance can be provided.

  Although one embodiment has been described above, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the invention.

In the manufacturing method and the manufacturing apparatus 70 of the electrode assembly 20 of the embodiment, once the number of positive 30 and negative electrodes 40 taken out from each group of electrodes _(P 1 to P ₈₎ and Fukyokugun _(N 1 to N ₉₎ However, the present invention is not limited to this example. For example, once the Fukyokugun _{N 1} and group of electrodes _{P 1,} twice from Fukyokugun _{N 2} and group of electrodes _{P 2,} three times from Fukyokugun _{N 3} and group of electrodes _{P 3,} Fukyokugun _{N 4} and the positive electrode The positive electrode 30 and the negative electrode 40 may be taken out from the group P ₄ four times (in order to increase in weight). Further, for example, four times from Fukyokugun _{N 5} and group of electrodes _{P 5,} three times from Fukyokugun _{N 6} and group of electrodes _{P 6,} twice from Fukyokugun _{N 7} and group of electrodes _{P 7,} Fukyokugun _{N 8} Alternatively, the positive electrode 30 and the negative electrode 40 may be taken out from the positive electrode group P ₈ and the negative electrode group N ₉ once (so as to increase gradually).

The weight distribution of the plurality of positive electrodes 30 housed in the stocker 73 often follows a normal distribution with the design weight of the positive electrode 30 as the center. As described above, only the positive electrodes 30 belonging to a predetermined positive electrode group can be obtained by relatively increasing the number of extractions from the positive electrode group (for example, the positive electrode groups P ₄ and P ₅ ) of the positive electrode 30 that frequently appears according to the normal distribution. It is possible to avoid such things as disappearing or remaining. The same applies to the plurality of negative electrodes 40 housed in the stocker 83. In addition, the frequency | count of the positive electrode 30 and the negative electrode 40 taken out from the positive electrode group and negative electrode group which were mentioned above is an illustration, and is not limited to what was mentioned above.

  Further, contrary to the manufacturing method and the manufacturing apparatus 70 of the electrode assembly 20 of the above embodiment, the positive electrode 30 and the negative electrode 40 are stacked so that the respective weights are gradually reduced, and a plurality of first semi-stacked bodies 20A are formed. It may be formed and stacked such that the weight of each of the positive electrode 30 and the negative electrode 40 is gradually reduced to form a plurality of second semi-laminates 20B. In this case, the electrode assembly 20 is formed by stacking one first half-laminate 20A and one second half-laminate 20B selected in the combination unit 93 so as to gradually become lighter in the laminating direction. be able to.

In the manufacturing method and the manufacturing apparatus 70 of the electrode assembly 20 of the above embodiment, as shown in FIG. 5, the _first positive electrode group P ₁ and the negative electrode group N ₁ to the fourth positive electrode group P ₄ and the negative electrode having the smallest weight. A group obtained by extracting up to the group N ₄ is a first group G ₁ , and the eighth positive electrode group P ₈ with the heaviest weight is extracted from the _fifth positive electrode group P _5, and the most from the fifth negative electrode group N ₅ a group obtained by extracting Fukyokugun N ₉ big ninth weight has been described as the second group G _2, the present invention is not limited thereto. For example, the first positive electrode group P ₁ having the smallest weight to the fourth positive electrode group P ₄ are extracted, and the first negative electrode group N ₁ having the smallest weight to the fifth negative electrode group N ₅ are extracted. The group is a first group G ₁ and the eighth positive electrode group P ₈ with the heaviest weight is extracted from the _fifth positive electrode group P ₅ and the ninth negative electrode group with the heaviest weight is extracted from the _sixth negative electrode group N _6. a group obtained by extracting N ₉ may be a second group _{G 2.} That is, in the manufacturing method of the electrode assembly 20 of another embodiment, the negative electrode group N ₁ , the positive electrode group P ₁ , the negative electrode group N ₂ , the positive electrode group P ₂ , the negative electrode group N ₃ , the positive electrode group P ₃ , and the negative electrode group N ₄ , the first half stack 20A is formed by taking out the negative electrode 40 and positive electrode 30 are alternately in the order of group of electrodes _{P 4} and Fukyokugun _{N 5,} group of electrodes _{P 5,} Fukyokugun _{N 6,} group of electrodes _{P 6,} Fukyokugun N _7, group of electrodes _{P 7,} Fukyokugun _{N 8,} may form a second half-stack 20B retrieves the positive electrode 30 and the negative electrode 40 are alternately in the order of group of electrodes _{P 8} and Fukyokugun _{N 9.}

In the manufacturing method and the manufacturing apparatus 70 of the electrode assembly 20 of the above embodiments, the positive electrode 30 and the negative electrode 40 of the second group G ₂ is taken out alternately, the cathode such that each weight of the positive electrode 30 and the anode 40 gradually becomes heavier Although the example in which the plurality of second semi-stacked bodies 20B are formed by alternately stacking 30 and the negative electrode 40 has been described, the present invention is not limited thereto. For example, the cathode 30 and the anode 40 of the second group G ₂ is taken out alternately stacked a positive electrode 30 and the negative electrode 40 so that the respective weight of the positive electrode 30 and negative electrode 40 becomes gradually lighter alternately a plurality of second half The stacked body 20B may be formed. That is, in the manufacturing method of the electrode assembly 20 according to another embodiment, the negative electrode group N ₉ , the positive electrode group P ₈ , the negative electrode group N ₈ , the positive electrode group P ₇ , the negative electrode group N ₇ , the positive electrode group P ₆ , and the negative electrode group N ₆ Alternatively, the positive electrode group P ₅ and the negative electrode group N ₅ may be alternately taken out in the order of the positive electrode 30 and the negative electrode 40 to form the second semi-stacked body 20B. In this case, as shown in FIG. 9, one first half loading end side of the laminate 20A ₃ electrode _(P 4 (30)) and one second half-loading end side of the laminate 20B ₂ of ( N ₅ (40)) electrodes are stacked so as to face each other with the separator 50 interposed therebetween, so that the electrode assembly 20 is formed. For example, the third stacked unit 121 holds the second semi-stacked body 20 </ b> B formed in one stocker 105 with a chuck (not shown) and the like, and the first semi-stacked layer formed in the one stocker 105. The chuck may be released in a state where it is moved to above the body 20A and is aligned and inverted upside down with respect to the first semi-stacked body 20A.

In the manufacturing method and the manufacturing apparatus 70 for the electrode assembly 20 according to the above-described embodiment, when the first half-layered body 20A and the second half-layered body 20B are stacked to form the electrode assembly 20, the both ends of the electrode assembly 20 are disposed. Although an example in which the polarity of the electrode is a negative electrode has been described, the present invention is not limited to this. For example, the polarity of the electrodes at both ends of the electrode assembly 20 may be a positive electrode. In this case, for example, the positive electrode group P ₁ , the negative electrode group N ₁ , the positive electrode group P ₂ , the negative electrode group N ₂ , the positive electrode group P ₃ , the negative electrode group N ₃ , the positive electrode group P ₄ , the negative electrode group N _4, and the positive electrode group P ₅ , the positive electrode 30 and the negative electrode 40 are alternately taken out to form the first semi-stacked body, and the negative electrode group N ₅ , the positive electrode group P ₆ , the negative electrode group N ₆ , the positive electrode group P ₇ , the negative electrode group N ₇ , The negative electrode 40 and the positive electrode 30 are alternately taken out in the order of the positive electrode group P ₈ , the negative electrode group N ₈ , and the positive electrode group P ₉ to form the second semi-stacked body 20B, and the electrode on the stacking end side (positive electrode) in the first semi-stacked body ) And the electrode (negative electrode) on the stacking start side in the second semi-stacked body are stacked so as to face each other with a separator interposed therebetween, so that the electrode assembly 20 may be formed.

Further, in the manufacturing method and a manufacturing apparatus 70 of the electrode assembly 20 of the above embodiments, for each of a plurality of positive electrodes 30 and negative electrodes 40, eight group of electrodes P ₁ to P ₈ and 9 of the negative electrode that is set based on the weight Although the example classified to each of the groups N _{1 to} N ₉ has been described, the present invention is not limited to this. For example, each of the plurality of positive electrodes 30 and negative electrodes 40 is divided into seven positive electrode groups P _{1 to} P ₇ and eight negative electrode groups N _{1 to} N ₈ that are set based on the weight. It suffices if a group is set.

  Moreover, in the manufacturing method and the manufacturing apparatus 70 of the electrode assembly 20 of the said embodiment, the example which performs sorting, stacking, combination, etc. based on the weight of the electrode highly relevant to the weight of an active material was given and demonstrated. Based on the idea of the present invention, the present invention is highly related to the weight of the active material. For example, sorting, stacking, and combination can be performed based on the thickness of the electrode.

10 ... case, 12 ... first metal plate, 14 ... second metal plate, 16: insulating member, 20 ... electrode _assembly, 20A 1 through 20a n _... first half _stack, 20B 1 _~20B n _... second half Laminated body, 30 ... positive electrode, 32 ... conductive member, 40 ... negative electrode, 42 ... conductive member, 50 ... separator, 60 ... electrolyte, 65 ... short-circuit unit, 70 ... manufacturing apparatus for electrode assembly, 71, 81 ... sorting section , 72, 82 ... conveying device, 73, 75, 83, 85, 105 ... stocker, 77 ... conveying device, 79 ... rail, 90 ... control unit, 93 ... combination unit, 101 ... first stacking unit, 103, 104 ... positioning unit, 111 ... second laminate section, 121 ... third laminated portion, 200 ... power storage device, G 1 _... first group, G 2 _... second _{group, N} 1 to N 9 _{... Fukyokugun,} P 1 to P ₈ ... group of electrodes, S1 ... sorting step, S2 ... 1 laminating step, S3 ... second laminating step, S4 ... combining step, S5 ... third laminating step.

Claims (11)

For each of a plurality of positive electrodes and negative electrodes, a sorting step for sorting each of the plurality of positive electrode groups and negative electrode groups set based on weight,
When arranged in each order on the basis of said plurality of cathode groups and Fukyokugun weight, weight smallest positive electrode group and the weight from the first to the weight m _P th is the most weight from a small 1 th m _N th The positive electrode and the negative electrode are alternately taken out from the negative electrode group, and the positive electrode and the negative electrode are alternately stacked so that the respective weights of the positive electrode and the negative electrode gradually increase or decrease, A first lamination step for forming a first semi-laminate;
From the negative electrode unit from the positive electrode group and m _N + 1-th weight +1 th m _P to the most significant n _P th until the weight is greatest n _N th weight, taking out the positive electrode and the negative electrode alternately, the positive electrode and A second laminating step of alternately stacking the positive electrode and the negative electrode so that the weight of each of the negative electrodes gradually increases or decreases, thereby forming a plurality of second semi-laminates;
An allowable range in which the weight of one first semi-laminate and one second semi-laminate out of the plurality of first semi-laminates and the plurality of second semi-laminates is based on a target value. A combination step of selecting a combination of the one first semi-laminate and the one second semi-laminate,
The one first semi-laminate and the one second semi-laminate selected in the combination step are made lighter or lighter so that the respective weights of the positive electrode and the negative electrode gradually increase along the laminating direction. A third stacking step of stacking so as to form an electrode assembly;
A method for manufacturing an electrode assembly, comprising: In the first stacking step, the positive electrodes and the negative electrodes are alternately stacked so that the respective weights of the positive electrode and the negative electrode gradually increase to form a plurality of first semi-stacked bodies,
In the second lamination step, the positive electrode and the negative electrode are alternately stacked so that the weights of the positive electrode and the negative electrode gradually increase to form a plurality of second semi-stacked bodies,
In the third lamination step, the one first semi-laminate and the one second half-laminate selected in the combination step are combined with the electrode on the stacking end side in the first semi-laminate and the second The electrode assembly is formed by stacking so that the electrodes on the stacking side in the semi-stacked body face each other.
The manufacturing method of the electrode assembly of Claim 1. The polarity of the electrode on the stacking end side in the first semi-laminate and the polarity of the electrode on the stacking start side in the second semi-laminate are different from each other,
The manufacturing method of the electrode assembly of Claim 2. In the first stacking step, the positive electrodes and the negative electrodes are alternately stacked so that the respective weights of the positive electrode and the negative electrode gradually increase to form a plurality of first semi-stacked bodies,
In the second stacking step, the positive electrode and the negative electrode are alternately stacked so that the respective weights of the positive electrode and the negative electrode are gradually reduced to form a plurality of second semi-stacked bodies,
In the third lamination step, the one first semi-laminate and the one second half-laminate selected in the combination step are combined with the electrode on the stacking end side in the first semi-laminate and the second The electrode assembly is formed by stacking so that the electrodes at the stacking end side in the semi-stacked body face each other.
The manufacturing method of the electrode assembly of Claim 1. The polarity of the electrode at the end of stacking in the first semi-stack and the polarity of the electrode at the end of stacking in the second semi-stack are different from each other,
The manufacturing method of the electrode assembly of Claim 4. Case and
The electrode assembly housed in the case and manufactured by the manufacturing method according to any one of claims 1 to 5,
A power storage device. For each of the plurality of positive electrodes and negative electrodes, a sorting unit that sorts each of the plurality of positive electrode groups and negative electrode groups set based on weight,
When arranged in each order on the basis of said plurality of cathode groups and Fukyokugun weight, weight smallest positive electrode group and the weight from the first to the weight m _P th is the most weight from a small 1 th m _N th The positive electrode and the negative electrode are alternately taken out from the negative electrode group, and the positive electrode and the negative electrode are alternately stacked so that the respective weights of the positive electrode and the negative electrode gradually increase or decrease, A first stack forming a first semi-stack,
From the negative electrode unit from the positive electrode group and m _N + 1-th weight +1 th m _P to the most significant n _P th until the weight is greatest n _N th weight, taking out the positive electrode and the negative electrode alternately, the positive electrode and A second laminated part that alternately stacks the positive electrode and the negative electrode so that the weight of each of the negative electrodes gradually increases or becomes light, and forms a plurality of second semi-laminates;
An allowable range in which the weight of one first semi-laminate and one second semi-laminate out of the plurality of first semi-laminates and the plurality of second semi-laminates is based on a target value. A combination unit for selecting a combination of the one first semi-laminate and the one second semi-laminate;
The one first semi-laminate and the one second semi-laminate selected by the combination unit are made lighter or lighter so that the respective weights of the positive electrode and the negative electrode gradually become heavier along the laminating direction. A third stacked portion that is stacked to form an electrode assembly;
An apparatus for manufacturing an electrode assembly. In the first stacked portion, the positive electrode and the negative electrode are alternately stacked so that the respective weights of the positive electrode and the negative electrode gradually increase to form a plurality of first semi-stacked bodies,
In the second stacked portion, the positive electrode and the negative electrode are alternately stacked so that the respective weights of the positive electrode and the negative electrode gradually increase to form a plurality of second semi-stacked bodies,
In the third stacked unit, the one first semi-stacked body and the one second semi-stacked body selected in the combination unit are combined with the electrode on the stacking end side in the first semi-stacked body and the second The electrode assembly is formed by stacking so that the electrodes on the stacking side in the semi-stacked body face each other.
The apparatus for manufacturing an electrode assembly according to claim 7. The polarity of the electrode on the stacking end side in the first semi-laminate and the polarity of the electrode on the stacking start side in the second semi-laminate are different from each other,
The apparatus for manufacturing an electrode assembly according to claim 8. In the first stacked portion, the positive electrode and the negative electrode are alternately stacked so that the respective weights of the positive electrode and the negative electrode gradually increase to form a plurality of first semi-stacked bodies,
In the second stacked unit, the positive electrode and the negative electrode are alternately stacked so that the weights of the positive electrode and the negative electrode are gradually reduced to form a plurality of second semi-stacked bodies,
In the third stacked unit, the one first semi-stacked body and the one second semi-stacked body selected by the combination unit are connected to the stacking end electrode in the first semi-stacked body and the second stack. The electrode assembly is formed by stacking so that the electrodes at the stacking end side in the semi-stacked body face each other.
The apparatus for manufacturing an electrode assembly according to claim 7. The polarity of the electrode at the end of stacking in the first semi-stack and the polarity of the electrode at the end of stacking in the second semi-stack are different from each other,
The apparatus for manufacturing an electrode assembly according to claim 10.

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