Power storage cell and method of manufacturing electrode body

Abstract

A capacitor cell comprises an electrode body, a cell case for housing the electrode body, and an electrolyte contained within the cell case. The electrode body comprises a plurality of positive electrodes and a plurality of negative electrodes arranged in a thickness direction, and a separator for insulating each positive electrode and each negative electrode. The electrode body has a shape that is longer in the width direction, which is orthogonal to both the thickness direction and the vertical direction, than in the thickness direction. The electrode body includes an upper portion, a bottom portion, a first end portion located at one end in the width direction, and a second end portion located at the other end in the width direction. The plurality of electrodes includes a plurality of positive electrodes and a plurality of negative electrodes. The plurality of positive electrodes include a positive electrode tab protruding from the first end portion. The plurality of negative electrodes include a negative electrode tab protruding from the second end portion. In the first end portion, a first weld portion is formed in a portion located below the positive electrode tab. In the second end, a second weld is formed in the portion located below the negative electrode tab. In the bottom portion, a third weld is formed in contact with the first weld and a fourth weld is formed in contact with the second weld. The third weld and the fourth weld are spaced apart with the central portion of the bottom portion in between.

Description

Technology Field

[0001] The present disclosure relates to a method for manufacturing a capacitor cell and an electrode body. Background Technology

[0002] Japanese Patent Publication No. 2009-88279 discloses a method for bonding an electrode and a separator, or separators to each other, using an adhesive mainly composed of a component identical to that of the electrode binder, in an electrode body in which an electrode containing a binder is laminated with a separator interposed therein.

[0003] The electrode body repeatedly expands and contracts as it undergoes repeated charging and discharging. During this process, the electrolyte flows in and out from the periphery of the electrode body. In the case of an electrode body formed horizontally, the electrolyte remains infiltrated in the surrounding area due to the inflow and outflow from the periphery. On the other hand, as time passes, the electrolyte tends to be depleted within the electrode body, particularly in the center. As a result, there is a risk that the permeation of the electrolyte within the electrode body may become uneven.

[0004] The object of the present disclosure is to provide a capacitive cell in which the permeation of the electrolyte within the electrode body is difficult to become uneven.

[0005] [1] An electrode body, a cell case for accommodating the electrode body, and an electrolyte contained within the cell case, and

[0006] The above electrode body comprises a plurality of positive electrodes and a plurality of negative electrodes arranged in a thickness direction, and a separator for insulating each positive electrode and each negative electrode.

[0007] The above electrode body has a shape that is longer in the width direction, which is orthogonal to both the thickness direction and the upper / lower direction, than in the thickness direction.

[0008] The electrode body comprises an upper portion, a bottom portion, a first end portion located at one end in the width direction, and a second end portion located at the other end in the width direction.

[0009] The plurality of positive electrodes above include a positive electrode tab protruding from the first end, and

[0010] The plurality of negative electrodes above include a negative tab protruding from the second end, and

[0011] In the first end portion above, a first weld portion is formed in the portion located below the positive electrode tab, and

[0012] In the second end portion above, a second weld portion is formed in the portion located below the negative electrode tab, and

[0013] In the bottom portion, a third weld portion in contact with the first weld portion and a fourth weld portion in contact with the second weld portion are formed.

[0014] The above third welded portion and the above fourth welded portion are spaced apart and arranged with a gap between them, with the central portion of the bottom portion in between, forming a capacitor cell.

[0015] The electrode body expands and contracts when charging and discharging are performed. Due to this expansion and contraction, the electrolyte flows in and out of the electrode body. Meanwhile, in the welded portion, the micropores of the separator are closed, preventing the electrolyte from passing through. Therefore, by forming welded portions at the lower ends of both sides in the width direction of the electrode body and at both sides of the bottom portion in the width direction of the electrode body, the entry and exit of the electrolyte in the welded portion is blocked. As a result, the electrolyte can be maintained in the corners of the bottom portion of the electrode body. Consequently, it becomes difficult for the permeation of the electrolyte within the electrode body to become uneven.

[0016] FIG. 1 is a schematic diagram showing the degree of electrolyte penetration in an electrode body in which a welded portion is not formed. In FIG. 1, the left-right direction represents the horizontal direction of the electrode body, and the up-down direction represents the up-down direction of the electrode body. As described above, it is believed that the electrolyte that has seeped into the corner portion of the bottom part of the electrode body seeps into the region (Z) in the center of FIG. 1, where the electrolyte is difficult to seep into, over time, thereby suppressing the variation in the degree of electrolyte penetration.

[0017] [2] The height of the first welded portion and the height of the second welded portion are at least one-third and no more than one-half of the height of the electrode body, respectively, of the capacitor cell described in [1].

[0018] [3] A capacitor cell described in [1] or [2], wherein the width of the third welded portion and the width of the fourth welded portion are at least one-fourth and at least one-third of the width of the electrode body.

[0019] [4] A method for manufacturing an electrode body in which a positive electrode and a negative electrode are arranged in a row with a separator interposed therebetween,

[0020] The process of preparing the above separator, and

[0021] A process of placing the positive electrode on the separator, and

[0022] A process of forming a folded portion that determines the position of the positive electrode relative to the separator by folding the separator back, and placing the separator on the positive electrode;

[0023] A process of welding the separator to the positive electrode by heating the separator, and

[0024] A process of placing the negative electrode on the separator welded on the positive electrode, and

[0025] A process of forming a folded portion that determines the position of the negative electrode relative to the separator by folding the separator back, and placing the separator on the negative electrode;

[0026] A method for manufacturing an electrode body comprising a process of welding the separator to the negative electrode by heating the separator.

[0027] The above and other objects, features, aspects, and advantages of the present invention will become clear from the following detailed description of the present invention, which is understood in conjunction with the accompanying drawings. Brief explanation of the drawing

[0028] Figure 1 is a schematic diagram showing the degree of electrolyte penetration in an electrode body in which a welded portion is not formed. FIG. 2 is an example of a perspective view schematically showing a capacitor cell in embodiment 1. Figure 3 is a cross-sectional view of the capacitor cell shown in Figure 2. FIG. 4A and FIG. 4B are examples of perspective views schematically showing an electrode body in Embodiment 1. FIG. 5 is a schematic diagram showing the electrode body in embodiment 2. FIG. 6 is a diagram schematically showing the method of manufacturing an electrode body in embodiment 2. FIG. 7 is a diagram schematically illustrating the method of manufacturing an electrode body in embodiment 2. FIG. 8 is a diagram schematically illustrating the method of manufacturing an electrode body in embodiment 2. FIG. 9 is a diagram schematically illustrating the method of manufacturing an electrode body in embodiment 2. FIG. 10 is a schematic diagram showing the electrode body in embodiment 3. FIG. 11 is a diagram schematically illustrating the method of manufacturing an electrode body in embodiment 3. FIG. 12 is a diagram schematically illustrating the method of manufacturing an electrode body in embodiment 3. FIG. 13 is a diagram schematically illustrating the method of manufacturing an electrode body in embodiment 3. FIG. 14 is a diagram schematically illustrating the method of manufacturing an electrode body in embodiment 3. FIG. 15 is a diagram schematically illustrating the method of manufacturing an electrode body in embodiment 3. FIG. 16 is a diagram schematically illustrating the method of manufacturing an electrode body in embodiment 3. FIG. 17 is a schematic diagram showing the electrode body in embodiment 4. Specific details for implementing the invention

[0029] <Embodiment 1>

[0030] The capacitor cell in this embodiment will be described with reference to the drawings. In addition, in the drawings referenced below, the same or equivalent components are given the same number.

[0031] FIG. 2 is an example of a perspective view schematically showing a capacitor cell in the present embodiment. FIG. 3 is a cross-sectional view of the capacitor cell shown in FIG. 2. FIG. 4A and FIG. 4B are examples of perspective views schematically showing an electrode body in the present embodiment.

[0032] As shown in FIGS. 2 and 3, the capacitor cell (1) comprises an electrode body (100), a cell case (200), a pair of external terminals (300), a pair of connecting members (400), an insulating member (500), and an electrolyte (not shown).

[0033] The electrode body (100) is provided with a plurality of positive electrodes (110) and a plurality of negative electrodes (120) arranged in a thickness direction (T in FIG. 2), and a separator (130) for insulating each positive electrode (110) and each negative electrode (120). The electrode body (100) is formed in a rectangular shape that is longer in a direction (W in FIG. 2) that is orthogonal to both the thickness direction and the vertical direction (H in FIG. 2) than in the thickness direction. The electrode body (100) includes an upper part (11), a bottom part (12), a first end part (13) located at one end in the width direction, and a second end part (14) located at the other end in the width direction.

[0034] Each positive electrode (110) is formed in a rectangular shape that is long in the width direction. Each positive electrode (110) has a positive electrode current collector and a positive electrode active material layer provided on both sides of the positive electrode current collector. The positive electrode (110), specifically the positive electrode current collector, includes a positive electrode tab (112p) that protrudes from the first end (13) toward one side in the width direction. The positive electrode tab (112p) is not provided with a positive electrode active material layer.

[0035] Each negative electrode (120) is formed in a rectangular shape that is long in the width direction. Each negative electrode (120) has a negative electrode collecting foil and a negative electrode active material layer provided on both sides of the negative electrode collecting foil. The negative electrode (120), specifically the negative electrode collecting foil, includes a negative electrode tab (122n) that protrudes from the second end (14) toward one side in the width direction. The negative electrode tab (122n) is not provided with a negative electrode active material layer.

[0036] In the first end (13), a first weld (15) is formed in the portion located below the positive electrode tab (112p). In the second end (14), a second weld (16) is formed in the portion located below the negative electrode tab (122n). In the bottom portion (12), a third weld (17) in contact with the first weld (15) and a fourth weld (18) in contact with the second weld (16) are formed. With this configuration, the entry and exit of the electrolyte in the first weld (15), the second weld (16), the third weld (17), and the fourth weld (18) can be blocked. As a result, the electrolyte can be maintained in the corner portions of the bottom portion (12) (near the first weld portion (15) and the third weld portion (17) and near the second weld portion (16) and the fourth weld portion (18)). Therefore, it is difficult for the electrolyte to seep unevenly into the interior of the electrode body (100).

[0037] The first welded part (15), the second welded part (16), the third welded part (17), and the fourth welded part (18) may be formed of resin, for example. The first welded part (15), the second welded part (16), the third welded part (17), and the fourth welded part (18) may be formed of the same resin or may be formed of different resins.

[0038] It is preferable that the height (H1) of the first welded portion (15) and the height (H2) of the second welded portion (16) are each at least one-third and no more than one-half of the height of the electrode body (100). By making the heights such, it is expected that the permeation of the electrolyte will be more uniform.

[0039] The third weld section (17) and the fourth weld section (18) are spaced apart by sandwiching the central part of the bottom section (12). This is because if a weld section is formed over the entire bottom section (12), the electrolyte cannot enter or exit from the bottom section (12).

[0040] It is preferable that the widthwise length (W1) of the third welded portion (17) and the widthwise length (W2) of the fourth welded portion (18) are each at least one-fourth and no more than one-third of the widthwise length of the electrode body (100). By making the lengths such, it is expected that the permeation of the electrolyte will be more uniform.

[0041] The separator (130) insulates the positive electrode (110) and the negative electrode (120). The separator (130) is made of an insulating material and has tiny pores that allow ion penetration.

[0042] The cell case (200) accommodates the electrode body (100). The cell case (200) contains an electrolyte that is not shown. The cell case (200) is sealed. The cell case (200) has a case body (210) and a cover (220).

[0043] The case body (210) has an opening that opens in the upward direction. The case body (210) is made of a metal such as aluminum. As shown in FIG. 3, the case body (210) has a bottom wall (212) and a perimeter wall (214). The bottom wall (212) is formed in a rectangular and flat shape. The perimeter wall (214) stands upright from the bottom wall (212). The perimeter wall (214) is formed in a rectangular tube shape. The length of the perimeter wall (214) in the width direction is longer than the length of the perimeter wall (214) in the thickness direction. The length of the perimeter wall (214) in the height direction is longer than the length of the perimeter wall (214) in the thickness direction.

[0044] The cover (220) closes the opening of the case body (210). The cover (220) is connected to the opening by welding or the like. The cover (220) is formed in a flat plate shape. The cover (220) is made of a metal such as aluminum. The cover (220) has a pressure release valve (222) and a sealing member (224).

[0045] A pressure release valve (222) is formed in the center of the cover (220). The pressure release valve (222) is formed to break when the internal pressure of the cell case (200) exceeds a predetermined pressure. As the pressure release valve (222) breaks, the gas inside the cell case (200) is released outside the cell case (200) through the pressure release valve (222), thereby lowering the internal pressure of the cell case (200).

[0046] The sealing member (224) seals the injection port (h) formed in the cover (220). The injection port (h) is a through hole for injecting an electrolyte into the cell case (200) during the manufacturing process of the capacitor cell (1). The injection port (h) is sealed by the sealing member (224) after the electrolyte is injected into the case body (210) through the injection port (h).

[0047] A pair of external terminals (300) are fixed on the cell case (200). One of the pair of external terminals (300) is a positive external terminal, and the other is a negative external terminal. Each external terminal (300) is fixed to the upper surface of the cover (220) via an upper insulating part (510) described later. Each external terminal (300) is made of a metal such as aluminum. Each external terminal (300) is formed, for example, in a rectangular shape. A bus bar, not shown, is connected to each external terminal (300) by welding or the like.

[0048] A pair of connecting members (400) connect a plurality of electrode tabs (112p, 122n) and an external terminal (300). One connecting member (400) connects a plurality of positive electrode tabs (112p) and a positive electrode external terminal (300), and the other connecting member (400) connects a plurality of negative electrode tabs (122n) and a negative electrode external terminal (300). Since each of the pair of connecting members (400) has substantially the same structure, one connecting member (400) will be described below.

[0049] The connecting member (400) has a current collection tap (410), a sub-tap (420), and a connecting pin (430).

[0050] The current collection tap (410) has a lateral portion (412) and an upper portion (414). The lateral portion (412) is located on the side of the electrode body (100) in the width direction. The upper portion (414) is located on the upper side of the electrode body (100). The upper portion (414) extends inward in the width direction from the upper end of the lateral portion (412).

[0051] The sub-tap (420) connects a plurality of positive pole taps (112p) to the current collection tap (410). One end (422) of the sub-tap (420) is connected to a plurality of positive pole taps (112p) by welding or the like, and the other end (424) of the sub-tap (420) is connected to a side portion (412) of the current collection tap (410) by welding or the like.

[0052] The connecting pin (430) connects the current collection tap (410) and the external terminal (300). The connecting pin (430) connects the upper portion (414) and the external terminal (300). Specifically, the lower portion of the connecting pin (430) is connected to the upper portion (414) by welding or the like while inserted into a through hole provided in the upper portion (414), and the upper portion of the connecting pin (430) is connected to the external terminal (300) by welding or caulking while inserted into a through hole provided in the external terminal (300).

[0053] The insulating member (500) insulates the cell case (200) and the connecting member (400). The insulating member (500) has an upper insulating part (510), a lower insulating part (520), an insulator (530), and an insulating plate (540).

[0054] The upper insulating portion (510) is fixed to the upper surface of the cover (220). The upper insulating portion (510) is positioned between the cover (220) and the external terminal (300). The upper insulating portion (510) is provided with an insertion hole through which a connecting pin (430) is inserted and passed.

[0055] The lower insulating portion (520) is fixed to the lower surface of the cover (220). The lower insulating portion (520) is positioned between the cover (220), the upper portion (414), and the lower portion of the connecting pin (430). The lower insulating portion (520) is provided with an insertion hole through which the connecting pin (430) is inserted and passed.

[0056] The insulator (530) is positioned between the connecting pin (430) and the cover (220). The insulator (530) is formed in a tubular shape and surrounds the connecting pin (430).

[0057] The insulating plate (540) is fixed to the lower surface of the upper portion (414). The insulating plate (540) is positioned above the electrode body (100). A through hole is provided in the portion of the insulating plate (540) located below the pressure release valve (222) and in the portion located below the injection port (h).

[0058] As described above, in the capacitor cell (1) of the present embodiment, a first welded portion (15) and a second welded portion (16) are respectively formed below the first end portion (13) and the second end portion (14) located at both ends in the width direction of the electrode body (100). Additionally, a third welded portion (17) and a fourth welded portion (18) are respectively formed at both ends of the bottom portion (12) of the electrode body (100). With this configuration, the entry and exit of the electrolyte in the first welded portion (15), the second welded portion (16), the third welded portion (17), and the fourth welded portion (18) can be blocked, making it difficult for the electrolyte to seep unevenly into the interior of the electrode body (100).

[0059] <Embodiment 2>

[0060] In this embodiment, the electrode body and the method for manufacturing the electrode body that can be used in Embodiment 1 are described with reference to the drawings. In addition, redundant descriptions regarding the same content as in Embodiment 1 are omitted.

[0061] FIG. 5 is a schematic diagram showing the electrode body in the present embodiment. In the present embodiment, the electrode body (100) comprises a plurality of positive electrodes (110) and a plurality of negative electrodes (120) arranged in a thickness direction, and a separator (130) formed in a zigzag shape to insulate each positive electrode (110) and each negative electrode (120). It has a shape that is longer in the width direction, which is orthogonal to both the thickness direction and the upper / lower direction, than in the thickness direction, and includes an upper part (11), a bottom part (12), a first end part (13) located at one end in the width direction, and a second end part (14) located at the other end in the width direction. The plurality of positive electrodes (110) include a positive electrode tab (112p) protruding from the first end part (13), and the plurality of negative electrodes (120) include a negative electrode tab (122n) protruding from the second end part (14). The separator (130) has a first back-folding section (131) and a second back-folding section (132). The first back-folding section (131) is formed at the first end (13). The second back-folding section (132) is formed at the second end (14). The first back-folding section (131) is welded to the positive electrode (110). The second back-folding section (132) is welded to the negative electrode (120).

[0062] In this embodiment, the separator (130) of the electrode body (100) is formed in a zigzag shape between each positive electrode (110) and each negative electrode (120), and is welded to the end of the positive electrode (110) and the end of the negative electrode (120). By doing so, the positional misalignment of the positive electrode (110) and the negative electrode (120) with respect to the separator (130) can be suppressed.

[0063] Next, the manufacturing process of the electrode body (100) will be described. The method for manufacturing an electrode body (100) in the present embodiment is a method for manufacturing an electrode body (100) in which a positive electrode (110) and a negative electrode (120) are arranged in a row with a separator (130) interposed therein, comprising: a process of preparing a separator (130) (preparation process); a process of placing a positive electrode (110) on a separator (130) (positive electrode placement process); a process of placing a separator (130) on a positive electrode (110) together with forming a first re-folding portion (131) that determines the position of the positive electrode (110) relative to the separator (130) by re-folding the separator (130) (first re-folding process); and a process of placing a negative electrode (120) on the separator (130) placed on the positive electrode (110) (negative electrode placement process). The method includes a process of forming a second re-folding portion (132) that determines the position of the negative electrode (120) relative to the separator (130) by re-folding the separator (130), a process of placing the separator (130) on the negative electrode (120) (second re-folding process), and a process of heating the first re-folding portion (131) and the second re-folding portion (132) to weld them to the positive electrode (110) and the negative electrode (120) (welding process).

[0064] In the preparation process, a long separator (130) is prepared.

[0065] In the positive electrode placement process, the positive electrode (110) is placed on the separator (130). Additionally, FIG. 6 shows the state after the positive electrode placement process.

[0066] In the first back-folding process, the separator (130) is back-folded so that the separator (130) is placed on the positive electrode (110). By doing so, a first back-folding portion (131) is formed on the separator (130). By this first back-folding portion (131), the position of the positive electrode (110) relative to the separator (130) is determined. That is, in this process, the separator (130) is back-folded to form a first back-folding portion (131) that determines the position of the positive electrode (110) relative to the separator (130), and at the same time, the separator (130) is placed on the positive electrode (110). Additionally, FIG. 7 shows the state after the first back-folding process.

[0067] In the negative electrode placement process, a negative electrode (120) is placed on a separator (130) placed on a positive electrode (110). Additionally, FIG. 8 shows the state after the negative electrode placement process.

[0068] In the second back-folding process, similar to the first back-folding process, the separator (130) is back-folded to form a second back-folding section (132) that determines the position of the negative electrode (120) relative to the separator (130), and the separator (130) is placed on the negative electrode (120). Additionally, FIG. 9 shows the state after the second back-folding process.

[0069] After that, the positive electrode placement process, the first back-folding process, the negative electrode placement process, and the second back-folding process are repeated in this order.

[0070] In the welding process, the first back-folding portion (131) and the second back-folding portion (132) are heated to weld to the positive electrode (110) and the negative electrode (120). The heating method is not particularly limited, but, for example, a heater may be used.

[0071] In the welding process, it is preferable to further heat at least one selected from the group consisting of the upper part (11) and the bottom part (12) to weld the separator (130) to the positive electrode (110) and the negative electrode (120). The electrode body (100) is, for example, mounted in a vehicle. When mounted in a vehicle, vibration is often applied in the vertical direction. Therefore, in the electrode body (100), by heating at least one selected from the group consisting of the upper part (11) and the bottom part (12) in the vertical direction, the positional misalignment of the positive electrode (110) and the negative electrode (120) relative to the separator (130) is further suppressed. In the welding process, it is more preferable to heat the upper part (11) and the bottom part (12) to weld the separator (130) to the positive electrode (110) and the negative electrode (120).

[0072] The upper part (11) and the bottom part (12) may be heated entirely or only partially. It is preferable to heat the entire upper part (11) and the bottom part (12).

[0073] As described above, in the electrode body (100) and the manufacturing method thereof in the present embodiment, the first fold-back portion (131) and the second fold-back portion (132) of the separator (130) are heated and welded, so that the positive electrode (110) and the negative electrode (120) are positioned relative to the separator (130), thereby suppressing the misalignment of the position of the positive electrode (110) and the negative electrode (120) relative to the separator (130).

[0074] <Embodiment 3>

[0075] In this embodiment, the electrode body and the method for manufacturing the electrode body that can be used in Embodiment 1 are described with reference to the drawings. In addition, redundant descriptions regarding contents such as Embodiments 1 and 2 are omitted.

[0076] FIG. 10 is a schematic diagram showing an electrode body in the present embodiment. The electrode body (100) in the present embodiment has the same structure as in embodiment 2.

[0077] The method of manufacturing the electrode body (100) in this embodiment is partially different from embodiment 2. The manufacturing method of the electrode body (100) in the present embodiment is a manufacturing method of the electrode body (100) in which a positive electrode (110) and a negative electrode (120) are arranged in a row with a separator (130) interposed therein, comprising: a process of preparing a separator (130) (preparation process); a process of placing a positive electrode (110) on a separator (130) (positive electrode placement process); a process of placing a separator (130) on a positive electrode (110) together with forming a re-folded portion (131) that determines the position of the positive electrode (110) relative to the separator (130) by re-folding the separator (130) (first re-folding process); a process of heating the first re-folded portion (131) to weld it to the positive electrode (110) (first welding process); and a positive electrode The method includes a process of placing a negative electrode (120) on a separator (130) placed on an electrode (110) (negative electrode placement process), a process of placing a separator (130) on a negative electrode (120) by forming a re-folding portion (132) that determines the position of the negative electrode (120) relative to the separator (130) by re-folding the separator (130) (second re-folding process), and a process of heating the second re-folding portion (132) to weld it to the negative electrode (120) (second welding process).

[0078] The method of manufacturing the electrode body (100) in this embodiment differs from embodiment 2 in that it has a first welding process and a second welding process. Below, the first welding process and the second welding process will be described. In addition, FIG. 11 shows the state after the positive electrode placement process, FIG. 12 shows the state after the first back-folding process, FIG. 14 shows the state after the negative electrode placement process, and FIG. 15 shows the state after the second back-folding process.

[0079] In the first welding process, the first back-folded bend portion (131) is heated and welded to the positive electrode (110). Additionally, FIG. 13 shows the state after the first welding process.

[0080] In the second welding process, the second folded bend portion (132) is heated and welded to the negative electrode (120). Additionally, FIG. 16 shows the state after the second welding process.

[0081] In this embodiment, the positive electrode placement process, the first back-folding process, the first welding process, the negative electrode placement process, the second back-folding process, and the second welding process are repeated in this order.

[0082] In this embodiment, a third welding process may be included in which at least one selected from the group consisting of the upper part (11) and the bottom part (12) is heated to weld the separator (130) to the positive electrode (110) and the negative electrode (120). In the third welding process, it is preferable to heat the upper part (11) and the bottom part (12) to weld them to the positive electrode (110) and the negative electrode (120).

[0083] The upper part (11) and the bottom part (12) may be heated simultaneously with heating the first back-folding part (131) and the second back-folding part (132) in the first welding process and the second welding process, so that the separator (130) is welded to the positive electrode (110) and the negative electrode (120). That is, in the case shown in FIGS. 13 and FIGS. 16, the separator (130) may be welded to the positive electrode (110) and the negative electrode (120) by sequentially heating the upper part and the bottom part during the electrode body formation process, simultaneously with heating the first back-folding part (131) and the second back-folding part (132).

[0084] As described above, in the electrode body (100) and the manufacturing method thereof in the present embodiment, the first fold-back portion (131) and the second fold-back portion (132) of the separator (130) are heated and welded, so that the positive electrode (110) and the negative electrode (120) are positioned relative to the separator (130), thereby suppressing the misalignment of the position of the positive electrode (110) and the negative electrode (120) relative to the separator (130).

[0085] <Embodiment 4>

[0086] In this embodiment, the electrode body and the method for manufacturing the electrode body that can be used in Embodiment 1 are described with reference to the drawings. In addition, redundant descriptions regarding contents such as Embodiments 1 to 3 are omitted.

[0087] FIG. 17 is a schematic diagram showing an electrode body in the present embodiment. In the present embodiment, the electrode body (100) comprises a plurality of positive electrodes (110) and a plurality of negative electrodes (120) arranged in a thickness direction, and a separator (130) formed in a zigzag shape to insulate each positive electrode (110) and each negative electrode (120). It has a shape that is longer in the width direction, which is orthogonal to both the thickness direction and the upper / lower direction, than in the thickness direction, and includes an upper part (11), a bottom part (12), a first end part (13) located at one end in the width direction, and a second end part (14) located at the other end in the width direction. The plurality of positive electrodes (110) include a positive electrode tab (112p) protruding from the first end part (13), and the plurality of negative electrodes (120) include a negative electrode tab (122n) protruding from the second end part (14). The separator (130) includes a first external separator (133), a second external separator (134), an internal separator (135), a first external backfold section (136), and a second external backfold section (137). The first external backfold section (136) connects the first external separator (133) and the internal separator (135). The second external backfold section (137) connects the second external separator (134) and the internal separator (135). The internal separator (135) has a first backfold section (131) and a second backfold section (132). The first back-folding section (131), the first outer back-folding section (136), and the second outer back-folding section (137) are formed on the first end (13). The second back-folding section (132) is formed on the second end (14). The first outer back-folding section (136) and the second outer back-folding section (137) have a chamfering shape.

[0088] In the present embodiment, the separator (130) of the electrode body (100) comprises, as shown in FIG. 17, a first outer separator (133) and a second outer separator (134) disposed at the outermost part in the thickness direction of the electrode body (100), an inner separator (135) disposed inside, a first outer back-folding portion (136) connecting the first outer separator (133) and the inner separator (135), and a second outer back-folding portion (137) connecting the second outer separator (134) and the inner separator (135). The first outer back-folding portion (136) and the second outer back-folding portion (137) have a chamfering shape. In the electrode body (100) having such a shape, the electrode body (100) can be smoothly inserted into the cell case by inserting it from the first end (13) having a chamfering shape. Additionally, the separator (130) is configured such that the first outer separator (133), the first outer re-folding portion (136), the inner separator (135), the second outer re-folding portion (137), and the second outer separator (134) are connected as one.

[0089] There are no specific restrictions on the chamfering shape, and it can be an angled flat shape (a flat shape with a rounded feel) rather than a sharp edge.

[0090] The method for manufacturing an electrode body (100) in the present embodiment is a method for manufacturing an electrode body (100) in which a positive electrode (110) and a negative electrode (120) are arranged with a separator (130) interposed therebetween, comprising: a process of preparing a separator (130) (preparation process); a process of placing a positive electrode (110) on a separator (130) (first positive electrode placement process); a process of placing a separator (130) on a positive electrode (110) together with forming a first external re-folding portion (136) that determines the position of the positive electrode (110) relative to the separator (130) by folding the separator (130) back (first external re-folding process); and a process of placing a negative electrode (120) on the separator (130) placed on the positive electrode (110) (negative electrode placement). A process (second reversing process) and, together with forming a reversing portion (132) that determines the position of the negative electrode (120) relative to the separator (130) by reversing the separator (130), a process of placing the separator (130) on the negative electrode (120), a process of placing the positive electrode (110) on the separator (130) placed on the negative electrode (120) (second positive electrode placement process), a process of placing the separator (130) on the positive electrode (110) together with forming a second outer reversing portion (137) that determines the position of the positive electrode (110) relative to the separator (130) by reversing the separator (130) (second outer reversing process), and a first outer reversing It includes a process (chamfering process) for forming a chamfered shape by heating the bending portion (136) and the second outer back-folding portion (137).

[0091] The method for manufacturing the electrode body (100) in this embodiment includes a chamfering process. The chamfering process will be explained below.

[0092] In the chamfering process, the first outer back-folding portion (136) and the second outer back-folding portion (137) are heated to form a chamfering shape. The chamfering shape is formed by heating, that is, the separator is hardened by heating. As a result, when the electrode body (100) is inserted into the cell case, even if the cell case and the chamfering portion of the electrode body (100) come into contact, damage to parts other than the chamfering portion of the electrode body (100) is suppressed.

[0093] As described above, in the electrode body (100) and the manufacturing method thereof according to the present embodiment, a first outer re-folding portion (136) and a second outer re-folding portion (137) are provided at the first end (13) of the first outer separator (133) and the second outer separator (134) disposed at the outermost part in the thickness direction of the electrode body (100), and the first outer re-folding portion (136) and the second outer re-folding portion (137) form a chamfering shape. In the electrode body (100) having such a shape, inserting the electrode body (100) smoothly into the cell case is achieved by inserting it into the cell case from the first end (13) having the chamfering shape. In addition, since the chamfering shape is formed by heating, when the electrode body (100) is inserted into the cell case, even if the cell case and the chamfering shape portion of the electrode body (100) come into contact, damage to parts other than the chamfering shape portion of the electrode body (100) is suppressed.

[0094] Although embodiments of the present invention have been described, the embodiments disclosed herein should be considered illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, and all modifications within the meaning and scope equivalent to the claims are intended to be included.

Claims

Claim 1 The apparatus comprises an electrode body, a cell case for housing the electrode body, and an electrolyte contained within the cell case. The electrode body comprises a plurality of positive electrodes and a plurality of negative electrodes arranged to be aligned in the thickness direction, and a separator for insulating each positive electrode and each negative electrode. The electrode body has a shape that is longer in the width direction, which is orthogonal to both the thickness direction and the upper / lower direction, than in the thickness direction. The electrode body includes an upper portion, a bottom portion, a first end portion located at one end in the width direction, and a second end portion located at the other end in the width direction. The plurality of positive electrodes each include a positive electrode tab protruding from the first end portion, and the plurality of negative electrodes each include a negative electrode tab protruding from the second end portion. In the first end portion, a first weld portion formed of resin is formed to cover a portion located below the positive electrode tab in the thickness direction of the electrode body. In the second end portion, a portion located below the negative electrode tab is the thickness of the electrode body. A capacitor cell having a second weld formed of resin covering in a direction, a third weld formed of resin covering a portion in contact with the first weld in the thickness direction of the electrode body in the bottom portion, and a fourth weld formed of resin covering a portion in contact with the second weld in the thickness direction of the electrode body, wherein the third weld and the fourth weld are spaced apart by sandwiching a central portion of the bottom portion where no weld is formed, the height of the first weld and the height of the second weld are each at least one-third and at least one-half of the height of the electrode body, and the width in the width direction of the third weld and the width in the width direction of the fourth weld are each at least one-fourth and at least one-third of the width in the electrode body. Claim 2 In claim 1, the separator is formed in a zigzag shape, and the separator has a first backfold bend portion and a second backfold bend portion, wherein the first backfold bend portion is formed at the first end and the second backfold bend portion is formed at the second end, a capacitor cell. Claim 3 In claim 1, the separator is formed in a zigzag shape, and the separator includes a first outer separator, a second outer separator, an inner separator, a first outer re-folding portion, and a second outer re-folding portion, wherein the first outer re-folding portion connects the first outer separator and the inner separator, and the second outer re-folding portion connects the second outer separator and the inner separator, and the inner separator has a first re-folding portion and a second re-folding portion, wherein the first re-folding portion, the first outer re-folding portion, and the second outer re-folding portion are formed at the first end, and the second re-folding portion is formed at the second end, and the first outer re-folding A capacitor cell having a bend portion and a second outer back-fold bend portion having a chamfering shape. Claim 4 delete

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