JP7109233B2 - Electrochemical device manufacturing method - Google Patents

Description

The present invention relates to a method for manufacturing an electrochemical device .

Secondary batteries, which are a type of electrochemical device, are widely used as power sources for portable electronic devices such as mobile phones, digital cameras, and laptop computers, power sources for vehicles, and power sources for households. Electrochemical devices include laminated electrochemical devices and wound electrochemical devices. A laminated electrochemical device has an electrode laminate in which two types of electrodes, that is, a positive electrode and a negative electrode, are alternately and repeatedly laminated via a separator. The electrode laminate is housed in the exterior container together with the electrolytic solution. Each of the positive electrode and the negative electrode has a coated portion in which an active material layer is formed on a current collector and an uncoated portion in which an active material layer is not formed on the current collector. Then, as described in Patent Documents 1 to 7, the current collectors of the uncoated portions located at the ends of the electrodes (positive electrode and negative electrode) are overlapped with each other, and the current collectors of the uncoated portions are overlapped. The body is joined to the electrode terminals (positive terminal and negative terminal). The positive electrode terminal and the negative electrode terminal extend outside the outer container, respectively, and connect the electrode laminate of the electrochemical device and an external electric circuit.

JP-A-2002-329493 JP 2009-187768 A JP 2002-298825 A Japanese Patent Application Laid-Open No. 2003-249209 JP 2007-234466 A JP 2017-168462 A JP 2005-317312 A

In the configurations described in Patent Documents 1 to 4, at one end in the stacking direction of the electrode laminate (the lower end in Patent Documents 1 to 3 and the upper end in Patent Document 4), the current collector in the uncoated portion They are superimposed on each other and joined to the electrode terminals. According to this configuration, the current collector in the non-coated portion of the electrode positioned near one end joined to the electrode terminal has a short distance to the joint portion with the electrode terminal. On the other hand, the current collector in the non-coated portion of the electrode located near the other end has a long distance to the joint portion with the electrode terminal. In particular, in a configuration in which the number of electrodes in the electrode laminate is large in order to improve the energy density per unit volume, the difference in the length of the uncoated portion of each electrode is large. Therefore, it is conceivable to change the length of the uncoated portion of each electrode, and eventually change the length of the entire current collector, according to the position in the stacking direction of the electrode laminate. However, in that case, the manufacturing of the electrodes becomes complicated, and there is a possibility that the characteristics such as the electric resistance value may change in each electrode. On the other hand, when electrodes having uncoated portions of the same length are used, the electrodes can be manufactured efficiently and easily, and the characteristics of all the electrodes are constant. However, the uncoated portion of the electrode located near the electrode terminal (near one end) is too long and becomes an obstacle. In addition, much material is wasted, which hinders cost reduction. Furthermore, with such a configuration in which the unapplied current collector and the electrode terminal are joined together at the ends in the stacking direction, the outer container has an asymmetrical shape. Although the portion on the electrode terminal side (one end side) that constitutes the exterior container is small and can be easily formed, the portion on the opposite side to the electrode terminals (the other end side) is large enough to accommodate almost all electrodes. must have a container for In particular, when the electrode laminate has a large number of layers, it is not easy to form a portion having such a large accommodating portion.

On the other hand, as disclosed in Patent Documents 5 to 7, an uncoated current collector is superimposed at an intermediate position (preferably at the center) between both ends in the stacking direction of the electrode stack. and the electrode terminal, the difference in the length of the uncoated portion of each electrode is relatively small. Therefore, the various problems mentioned above are mostly solved. However, in this configuration, the current collector in the non-coated portion of the electrode positioned at one end in the stacking direction is pulled to the intermediate position and then contacted and joined to the electrode terminal. That is, the unapplied portion of the current collector is pulled from one end to the intermediate position, so that the current collector contacts the electrode terminal under tension. Then, in order to join the current collector and the electrode terminal of the uncoated portion to each other, pressure is applied while heat and ultrasonic vibration are applied using a welding member (horn, anvil, etc.). At this time, the uncoated portion of the current collector is brought into contact with the edge of the electrode terminal under tension, and is pressed by the welding member via the electrode terminal, so that it is very easily damaged. In particular, since the electrode terminal is thicker than the current collector, the current collector is easily torn when the edge of the electrode terminal rubs against the uncoated portion of the current collector.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above-described problems and to provide a method of manufacturing an electrochemical device in which electrodes are less likely to be damaged.

The method for manufacturing an electrochemical device of the present invention is characterized in that an active material layer is formed on a part of a current collector, an application part in which the active material layer is formed on the current collector, and an active material layer on the current collector. a step of forming two types of electrodes having an uncoated portion where is not formed; a step of alternately laminating the two types of electrodes with a separator interposed therebetween to form an electrode laminate; a step of overlapping current collectors of uncoated portions at an intermediate position between both end portions in the stacking direction of the electrode laminate, and a step of joining the stacked current collectors of uncoated portions to electrode terminals; including , from one end side in the stacking direction from the boundary portion with the coated portion of the current collector of the uncoated portion of at least one electrode to the joint portion joined to the electrode terminal After extending toward the other end side and maintaining the same height as the intermediate position in the stacking direction, or once extending from one end side in the stacking direction to the other end side beyond the intermediate position, Further comprising forming a position defining portion returning to the intermediate position, the forming of the position defining portion being performed in the step of overlapping the current collectors of the uncoated portions or overlapping the current collectors of the uncoated portions. Between the step and the step of joining the uncoated portion of the current collector to the electrode terminal, the portion of the overlapping uncoated portion of the current collector between the boundary portion with the coated portion and the joining portion is This is done by pushing up using a pushing member.
Another feature of the method for manufacturing an electrochemical device of the present invention is that an active material layer is formed on a part of the current collector, and an application portion in which the active material layer is formed on the current collector and a step of forming two types of electrodes having an uncoated portion where an active material layer is not formed; a step of alternately laminating the two types of electrodes via a separator to form an electrode laminate; overlapping the current collectors of the uncoated portions of the electrode at an intermediate position between both ends in the stacking direction of the electrode laminate; and, between the boundary portion with the coated portion of the current collector of the uncoated portion of at least one electrode and the joint portion joined to the electrode terminal, one end side in the stacking direction to the other end side and then maintain the same height as the intermediate position in the stacking direction, or once extend from one end side in the stacking direction to the other end side beyond the intermediate position forming a position defining portion returning to the intermediate position from the The portion of the body between the boundary portion with the application portion and the joint portion is pushed up from one end side toward the other end side using a pushing member.

According to the present invention, it is possible to obtain an electrochemical device whose electrodes are less likely to be damaged.

1 is a cross-sectional view showing a main part of an electrochemical device according to a first embodiment of the invention; FIG. FIG. 2 is a plan view of an electrochemical device according to a second embodiment of the invention; FIG. 2B is a cross-sectional view taken along the line AA of FIG. 2A; FIG. 3 is a cross-sectional view showing a formation state of a position defining portion in the method of manufacturing the electrochemical device shown in FIGS. 2A and 2B; 2C is a cross-sectional view showing another example of the formation state of the position defining portion in the method of manufacturing the electrochemical device shown in FIGS. 2A and 2B; FIG.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a main part of an electrochemical device according to a first embodiment of the invention. The electrochemical device of this embodiment has an electrode laminate 4 in which two types of electrodes (a positive electrode 1 and a negative electrode 2) are alternately stacked with separators 3 interposed therebetween. Electrodes 1 and 2 respectively have coated portions where active material layers 1b and 2b are formed on current collectors 1a and 2a, and uncoated portions where active material layers 1b and 2b are not formed on current collectors 1a and 2a. have The current collectors 1a of the uncoated portions of the positive electrode 1 are overlapped at an intermediate position C between both ends in the stacking direction S of the electrode stack 4 and joined to the electrode terminal (positive electrode terminal) 5. . At least one current collector 1a of the uncoated portion of the positive electrode 1 is located on one end side in the stacking direction (Fig. 1 1) and then maintain the same height as the middle position C in the stacking direction S, or from one end side in the stacking direction S to the middle It has a position regulating portion 6 that once extends beyond the position C to the other end side and then returns to the intermediate position.

According to this embodiment, the current collector 1a of the uncoated portion of the positive electrode 1 located on one end side (lower side in FIG. 1) in the stacking direction S is placed on the other end side (upper side in FIG. 1). It extends and is joined to the positive electrode terminal 5 at an intermediate position C in the stacking direction S. More specifically, the uncoated current collector 1a in the example shown in FIG. It is returned to the intermediate position and joined to the positive electrode terminal 5 . A tension is applied to the uncoated portion of the current collector 1a to extend it from one end side to the other end side. , and reaches the intermediate position C by returning to one end side. Therefore, the tension for extending from one end side to the other end side is not applied so much to the portion joined to the positive electrode terminal 5 . As a result, even if it comes into contact with the positive electrode terminal 5, it is less likely to be damaged. Although FIG. 1 shows the junction between the positive electrode 1 and the positive electrode terminal 5 and its surroundings, the negative electrode 2 and the negative electrode terminal described later and its surroundings also have the same configuration as in FIG.

2A and 2B show a secondary battery as an example of the electrochemical device according to the present invention. FIG. 2A is a schematic plan view seen from above perpendicular to the main surface (flat surface) of the secondary battery. FIG. 2B is a cross-sectional view taken along line AA of FIG. 2A. This secondary battery is a more specific and detailed embodiment (second embodiment) than the electrochemical device of the first embodiment shown in FIG. The electrochemical device of this embodiment has an electrode laminate 4 in which positive electrodes 1 and negative electrodes 2 are alternately stacked with separators 3 interposed therebetween, as in the first embodiment. This electrode laminate 4 is housed in an exterior container 8 made of a flexible film (laminate film) together with an electrolytic solution 7 . Uncoated current collectors 1a and 2a of positive electrode 1 and negative electrode 2 are used as electrode tabs (positive electrode tab, negative electrode tab) for connecting to electrode terminals (positive electrode terminal 5, negative electrode terminal 9). The current collectors (positive electrode tabs) 1a of the uncoated portions of the positive electrode 1 are overlapped on one end of the positive electrode terminal 5 and connected to each other by ultrasonic welding or the like. Similarly, current collectors (negative electrode tabs) 2a of uncoated portions of the negative electrode 2 are overlapped on one end of the negative electrode terminal 9 and connected to each other by ultrasonic welding or the like. The other end of the positive electrode terminal 5 and the other end of the negative electrode terminal 9 extend to the outside of the external container 8 made of a flexible film. In FIG. 2B, the electrolytic solution 7 is shown by omitting a part of each layer constituting the electrode laminate 4 (the layer located in the middle in the thickness direction). It is preferable that the outer dimensions of the applied portion (active material layer 2b) of the negative electrode 2 are larger than the outer dimensions of the applied portion (active material layer 1b) of the positive electrode 1 and smaller than or equal to the outer dimensions of the separator 3. A plurality of uncoated current collectors (positive electrode tabs) 1a may be sandwiched between the positive electrode terminal 5 and the support tab 10 and fixed. A plurality of uncoated current collectors (negative electrode tabs) 2 a that are superimposed may be fixed while being sandwiched between the negative electrode terminal 9 and the support tab 10 . FIG. 2B omits part of the current collectors 1a and 2a in the non-coated portions in the same way as part of each layer constituting the electrode laminate 4 is omitted. 2 is illustrated as being sandwiched between the electrode terminals 5 and 9 and the support tab 10 with appropriate modifications.

In such a configuration, as in the first embodiment, the current collectors 1a and 2a of the uncoated portions of at least one of the positive electrode 1 and the negative electrode 2 are connected to the electrode terminals 5 and 9 from the boundary portions with the coated portions. It has a position regulating part 6 between the joined parts. The position defining portion 6 once extends from one end side (bottom side in the vertical direction) in the stacking direction S to the other end side (upper side in the vertical direction) beyond the intermediate position C, and then returns to the intermediate position C again. It has a curved shape to be joined to the electrode terminals 5 and 9 through the joint. In this configuration, in particular, the uncoated current collectors 1a and 2a located on one end side (at least the uncoated current collectors 1a and 2a located on the most one end side) are provided with the above-described It has a position regulating part 6 . However, the unapplied current collectors 1a and 2a located on the other end side may not necessarily have the position defining portion 6 .

A method for manufacturing this secondary battery will be described. In the manufacture of this secondary battery, first, active material layers 1b and 2b are formed on both sides of current collectors 1a and 2a, respectively, and the active material layers 1b and 2b are formed on current collectors 1a and 2a. Two types of electrodes (a positive electrode 1 and a negative electrode 2) are formed, each having a portion and an uncoated portion where the active material layers 1b and 2b are not formed on the current collectors 1a and 2a. A plurality of positive electrodes 1 and a plurality of negative electrodes 2 are alternately and repeatedly laminated with separators 3 in between to form an electrode laminate 4 . Then, the uncoated current collector (positive electrode tab) 1a at one end of the plurality of positive electrodes 1 is overlapped. Similarly, the uncoated current collector (negative electrode tab) 2a at one end of the plurality of negative electrodes 2 is overlapped. Further, the current collector 1a of the uncoated portion of the superimposed positive electrode 1 is sandwiched between the positive electrode terminal 5 and the support tab 10, and these are joined together. Further, in a state in which the uncoated current collector 2a of the superimposed negative electrode 2 is sandwiched between the negative electrode terminal 9 and the support tab 10, they are joined together. The electrode laminate 4 is covered from above and below with an upper container portion 8a and a lower container portion 8b each made of a flexible film (laminate film). The container upper portion 8 a has a housing portion for housing a part of the electrodes 1 and 2 and the separator 3 that constitute the electrode laminate 4 . The container lower portion 8b has a housing portion for housing the remaining portions of the electrodes 1 and 2 and the separator 3 that constitute the electrode laminate 4. As shown in FIG. The outer container 8 is formed by joining the peripheral edges of the container upper portion 8a and the container lower portion 8b together, and the electrode laminate 4 and the electrolytic solution 7 are accommodated in the outer container 8 . The positive electrode terminal 5 and the negative electrode terminal 9 extend outward from the exterior container 8 through the joint portion of the periphery of the container upper portion 8a and the container lower portion 8b.

The main feature of the manufacturing method of the secondary battery of the present embodiment described above is that the current collector (positive electrode tab) 1a of the uncoated portion of the positive electrode 1 and the positive electrode terminal 5 are overlapped and joined, and one side of the negative electrode 2 is The uncoated portion of the current collector (negative electrode tab) 2a and the negative electrode terminal 9 are overlapped and joined. That is, as shown in FIG. 3, the overlapping current collector 1a of the uncoated portion is sandwiched between the positive electrode terminal 5 positioned vertically below and the support tab 10 positioned vertically above. Then, welding members (horn 11, anvil 12, etc.) are pressed from above and below against the portion where all of these overlap. Furthermore, in the present embodiment, the position between the boundary portion with the application portion and the joint portion between the electrode terminals 5 and 9, in other words, the portion where the positive electrode 1 and the negative electrode 2 overlap, the horn 11 and the anvil 12 A pressing jig 13 pushes up the unapplied portion of the current collector 1a from vertically below at a position between the portion to be pressed. This pushing jig 13 is pushed from one end side (bottom side in the vertical direction) beyond the portion (intermediate position C) where the current collector 1a of the uncoated portion and the positive electrode terminal 5 are joined to the other end side. It extends until the tip is positioned (upper in the vertical direction). By being pushed up by the pushing jig 13, the position defining portion 6 having a bent shape is formed on the unapplied portion of the current collector 1a. The position of the pushed-up uncoated current collector 1a is the portion where the uncoated current collector 1a is finally joined to the positive electrode terminal 5, that is, the portion sandwiched between the horn 11 and the anvil 12 (middle position). It is above the position C) in the stacking direction S (vertically above). According to this method, the current collector 1a of the uncoated portion and the positive electrode terminal 5 are joined while a part of the current collector 1a of the uncoated portion is pushed up using the pressing jig 13 . Thereby, the position defining portion 6 having the bent shape described above is formed. A tension is applied to the current collector 1a of the uncoated portion to push it up from the vertically downward direction to the intermediate position C. is converted, the tension is relieved. Therefore, the current collector 1a of the uncoated portion and the positive electrode terminal 5 can be joined without causing breakage even at the portion where the edge of the positive electrode terminal 5 contacts the current collector 1a of the uncoated portion. Although not shown, in the negative electrode 2 as well, by forming the position defining portion 6 having a bent shape using the pressing jig 13, the portion where the edge of the negative electrode terminal 9 abuts the current collector 2a of the uncoated portion. However, the current collector 2a and the negative electrode terminal 9 in the unapplied portion can be joined without damage.

As a modification of the present embodiment, as shown in FIG. 4, the tip of the pressing jig 13 is a portion where the unapplied portions of the current collectors 1a and 2a and the electrode terminals 5 and 9 are joined in the stacking direction S ( It may be located in an intermediate position C). In that case, even if the current collectors 1a and 2a of the uncoated portions do not have the bent shape as in the first and second embodiments, but have the position defining portion 6 held at the intermediate position C, good.

The first and second embodiments described above are configured such that the electrode terminals 5 and 9 are brought into contact with and joined to the current collectors 1a and 2a in the overlapping uncoated portions from vertically below. Therefore, the pressing jig 13 extends vertically upward from the vertically downward direction. Then, the position regulating portion 6 of the current collectors 1a and 2a of the uncoated portion extends vertically from below to the intermediate position C and maintains the height, or once extends vertically above the intermediate position C and then It is back to the middle position again. However, if the electrode terminals 5 and 9 are in contact with and joined to the superimposed uncoated current collectors 1a and 2a from the vertical upper side, the electrode terminals 5 and 9 are joined from the vertical upper side to the vertical lower side. Use a pushing jig that extends Then, the position defining portion of the current collectors 1a and 2a of the uncoated portion extends vertically from above to the intermediate position C and maintains the height, or once extends vertically below the intermediate position C and then again. formed to return to an intermediate position. Further, when the electrode terminals 5 and 9 are configured to abut against the current collectors 1a and 2a of the non-coated portions from a direction different from the vertical direction, the current collectors 1a and 2a are pushed from the side where the electrode terminals 5 and 9 are located. A pressing jig that extends toward the side where it is located may be used. In this case, the position-defining portions of the current collectors 1a and 2a of the uncoated portions extend from the side where the electrode terminals 5 and 9 are located to the intermediate position C and maintain the height thereof, or the current collectors 1a and 2a are It is formed so as to once extend beyond the intermediate position C toward the side where 2a is located, and then return to the intermediate position C again. To explain the reason for this, it is the portions where the slightly sharp edges of the electrode terminals 5 and 9 abut that the uncoated portions of the current collectors 1a and 2a are likely to be damaged. This is when the terminals 5 and 9 are pressed and the edges bite into the uncoated portions of the current collectors 1a and 2a. Therefore, in order to suppress breakage of the current collectors 1a and 2a in the non-coated portions, the pressure acting on the contact portions between the current collectors 1a and 2a in the non-coated portions and the electrode terminals 5 and 9 should be reduced. is desirable. Pressurization of the welding members (horn 11 and anvil 12) for welding the current collectors 1a and 2a and the electrode terminals 5 and 9 on the uncoated portions cannot be suppressed. However, the tension applied to the uncoated collectors 1a and 2a can be reduced by pulling the uncoated collectors 1a and 2a to the position (intermediate position C) where they are joined to the electrode terminals 5 and 9. , it is possible to absorb and reduce the pressure acting on the contact portions with the electrode terminals 5 and 9 . In order to reduce the force applied to the current collectors 1a and 2a in the unapplied portions at the joining positions (intermediate positions C) with the electrode terminals 5 and 9, the structure shown in FIG. 3 is effective. That is, the current collectors 1a and 2a of the non-coated portion once pass the joint position (intermediate position C) with the electrode terminals 5 and 9, and the opposite side of the electrode terminals 5 and 9 2a side), it is preferably returned to the intermediate position C and brought into contact with the electrode terminals 5 and 9 . However, as shown in FIG. 4, the current collectors 1a and 2a of the non-coated portions reach the junction position (intermediate position C) with the electrode terminals 5 and 9 and maintain the same height as the intermediate position C. A certain degree of effect can be obtained even with a structure in which the contact portions are in contact with the electrode terminals 5 and 9 .

A support tab 10 is also in contact with the current collectors 1a and 2a in the overlapping uncoated portions from the opposite side of the electrode terminals 5 and 9. As shown in FIG. However, the support tab 10 is generally much thinner than the electrode terminals 5, 9 and somewhat flexible. Therefore, even if the support tab 10 comes into contact with the current collectors 1a and 2a, the non-coated portions of the current collectors 1a and 2a are less likely to be damaged. Therefore, a special configuration for suppressing damage to the unapplied portions of the current collectors 1a and 2a by the support tabs 10 may not be provided.

In the example shown in FIGS. 3 and 4, the position regulating portion 6 is formed on the uncoated portions of the current collectors 1a and 2a using the pressing member 13 during welding, but the present invention is not limited to this. Before welding, for example, at the time of forming the electrode stack 4, the position defining portion 6 may be formed using the pressing member 13 or a similar member. In this case, the electrode terminals 5 and 9 are joined to the uncoated current collectors 1a and 2a on which the position defining portions 6 have already been formed. , 9 is small, and damage to the current collectors 1a, 2a is suppressed in the same manner as in the examples shown in FIGS.

The shape and detailed configuration of the pressing jig 13 are not particularly limited. Even if it is not a rod-shaped jig as shown in FIGS. It is sufficient if the shape is such that it can be pressed by an appropriate amount. The pressing jig 13 may be fixed or may be configured to move back and forth in the pressing direction. The pressing jig 13 preferably extends over the entire widthwise length of the uncoated portions of the current collectors 1a and 2a.

Examples of materials for each member constituting the secondary battery of the present invention described above will be described below. Examples of the active material constituting the active material layer 1b of the positive electrode include LiCoO ₂ , LiNiO ₂ , LiMn ₂ O ₂ , Li ₂ MO ₃ -LiMO ₂ , LiNi _1/3 Co _1/3 Mn _1/3 O ₂ and the like. Layered oxide materials, spinel materials such as LiMn ₂ O ₄ , olivine materials such as LiMPO ₄ , olivine fluoride materials such as Li ₂ MPO ₄ F and Li ₂ MSiO ₄ F, and V ₂ O ₅ and the like. Examples include vanadium oxide-based materials (M is a transition metal). In each active material, some of the elements constituting these active materials may be substituted with other elements, and Li may be excessive. One or a mixture of two or more of these active materials can be used.

Examples of active materials constituting the active material layer 2b of the negative electrode include carbon materials such as graphite, amorphous carbon, diamond-like carbon, fullerene, carbon nanotubes, and carbon nanohorns, lithium metal materials, and alloy materials such as silicon and tin. , Nb ₂ O ₅ and TiO ₂ , or composites thereof.

The active material mixture constituting the active material layers 1b and 2b of the positive electrode and the negative electrode is obtained by appropriately adding a binder, a conductive agent, and the like to each of the active materials described above. As the conductive aid, carbon black, carbon fiber, graphite, or the like can be used alone or in combination of two or more. As the binder, polyvinylidene fluoride, polytetrafluoroethylene, carboxymethylcellulose, styrene-butadiene rubber, modified acrylonitrile rubber particles, and the like can be used.

In both of the active material layers 1b and 2b of the positive and negative electrodes, there may be unavoidable inclination, unevenness, roundness, etc. of each layer due to, for example, variations in manufacturing and layer forming ability.
As the current collector 1a of the positive electrode, aluminum, stainless steel, nickel, titanium, alloys thereof, or the like can be used, and aluminum is particularly preferable. As the current collector 2a of the negative electrode, copper, stainless steel, nickel, titanium, or alloys thereof can be used.

Examples of the electrolyte solution 7 include cyclic carbonates such as ethylene carbonate, propylene carbonate, vinylene carbonate, and butylene carbonate, ethyl methyl carbonate (EMC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), and the like. chain carbonates, aliphatic carboxylic acid esters, γ-lactones such as γ-butyrolactone, chain ethers, cyclic ethers, and other organic solvents. Mixtures can be used. Furthermore, lithium salts can be dissolved in these organic solvents.

The separator 3 is mainly made of a resin porous film, woven fabric, non-woven fabric, etc., and its resin components include, for example, polyolefin resins such as polypropylene and polyethylene, polyester resins, acrylic resins, styrene resins, nylon resins, aramid resins (aromatic Polyamide resin), polyimide resin, or the like can be used. In particular, a polyolefin-based microporous film is preferable because of its excellent ion permeability and ability to physically separate the positive electrode and the negative electrode. Moreover, a layer containing inorganic particles may be formed on the separator 3 as necessary. Examples of inorganic particles include insulating oxides, nitrides, sulfides, carbides, etc. Among them, TiO ₂ and Al ₂ O ₃ are preferably included.

The exterior container 8 is a lightweight exterior case made of a flexible film, and the flexible film is a laminated film in which a resin layer is provided on both sides of a metal foil serving as a base material. A metal foil having a barrier property for preventing leakage of the electrolytic solution 7 and entry of moisture from the outside can be selected as the metal foil, and aluminum, stainless steel, or the like can be used. At least one surface of the metal foil is provided with a heat-sealable resin layer such as modified polyolefin. The exterior container 8 is formed by placing the heat-sealable resin layers of the flexible film facing each other and heat-sealing the periphery of the portion where the electrode laminate 4 is to be accommodated. A resin layer such as a nylon film, a polyethylene terephthalate film, a polyester film, or the like can be provided as the surface of the outer container 8 on the surface of the metal foil opposite to the surface on which the heat-sealable resin layer is formed.

As the positive electrode terminal 5, one made of aluminum or an aluminum alloy can be used. As the negative electrode terminal 9, copper, a copper alloy, nickel-plated material thereof, nickel, or the like can be used. The other end portions of the electrode terminals 5 and 9 are drawn out of the exterior container 8 . A heat-fusible resin (sealing material) can be provided in advance at portions of the electrode terminals 5 and 9 corresponding to the portions to be heat-sealed on the outer peripheral portion of the outer container 8 .

Although the present invention is particularly useful for lithium ion secondary batteries, it is also effective when applied to secondary batteries other than lithium ion batteries and electrochemical devices other than batteries such as capacitors.

1 positive electrode (electrode)
1a, 2a Current collectors 1b, 2b Active material layer 2 Negative electrode (electrode)
3 Separator 4 Electrode laminates 5 and 9 Electrode terminal 6 Position defining portion

Claims (4)

An active material layer is formed on a part of a current collector, and an applied portion where the active material layer is formed on the current collector and an uncoated portion where the active material layer is not formed on the current collector. forming two types of electrodes having
a step of alternately stacking the two types of electrodes via a separator to form an electrode stack;
a step of overlapping the current collectors of the uncoated portions of the electrodes of the same type at an intermediate position between both ends in the stacking direction of the electrode stack;
and joining the overlapping current collector of the uncoated portion to an electrode terminal;
One end in the stacking direction of the current collector of the uncoated portion of at least one of the electrodes, from the boundary portion with the coated portion to the joint portion joined to the electrode terminal or maintain the same height as the intermediate position in the stacking direction after extending from the one end side toward the other end side, or extend from the one end side in the stacking direction beyond the intermediate position to the other side. further comprising forming a position defining portion that once extends to the end of the and then returns to the intermediate position;
The position defining portion is formed in the step of overlapping the current collectors of the uncoated portions, or in the step of overlapping the current collectors of the uncoated portions and the current collector of the uncoated portions. to the electrode terminal, the portion between the boundary portion with the applied portion and the joint portion of the overlapping unapplied portion of the current collector is removed using a pressing member A method for manufacturing an electrochemical device, characterized in that the method is carried out by pushing up with a bar . An active material layer is formed on a part of a current collector, and an applied portion where the active material layer is formed on the current collector and an uncoated portion where the active material layer is not formed on the current collector. forming two types of electrodes having
a step of alternately stacking the two types of electrodes via a separator to form an electrode stack;
a step of overlapping the current collectors of the uncoated portions of the electrodes of the same type at an intermediate position between both ends in the stacking direction of the electrode stack;
and joining the overlapping current collector of the uncoated portion to an electrode terminal;
One end side in the stacking direction of the current collector of the uncoated portion of at least one of the electrodes, from the boundary portion with the coated portion to the joint portion joined to the electrode terminal to the other end side and then maintain the same height as the intermediate position in the stacking direction, or from the one end side in the stacking direction beyond the intermediate position to the other end further comprising forming a position defining portion that once extends toward the portion and then returns to the intermediate position;
In the step of joining the current collector of the unapplied portion to the electrode terminal, the position defining portion is formed by forming a boundary portion of the current collector of the unapplied portion overlapped with the applied portion. A method for manufacturing an electrochemical device, wherein the portion between the joining portion is pushed up from the one end portion side toward the other end portion side using a pushing member. 3. The method of manufacturing an electrochemical device according to claim 1 , wherein said pressing member is arranged between said application portion and said joint portion. further comprising the step of accommodating the electrode laminate and the electrolyte in an outer container, wherein when the electrode laminate and the electrolyte are accommodated, part of the electrodes and the separators constituting the electrode laminate are 2. The exterior container is configured by joining a portion having a housing portion for housing and a portion having a housing portion for housing the remaining portions of the electrodes and the separators constituting the electrode laminate. 4. The method for producing an electrochemical device according to any one of 3 .

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