JP2011176136A - Electrochemical device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a winding type electrochemical device having superior impedance characteristics. <P>SOLUTION: A belt-like electrode composing an anode electrode A includes a belt-like main metal foil A1 and a pair of active material layers AE1, AE2, respectively provided on both surfaces of the main metal foil A1. A belt-like electrode composing a cathode electrode K includes a belt-like main metal foil K2 and a pair of active material layers KE1, KE2, respectively provided on both surfaces of the main metal foil K2. Exposed regions where the active material layers AE2, KE2 are not formed are set on respective one-surface sides of the main metal foils, in regions where the main metal foils do not overlap each other. Respectively on the other surface sides, the active material layers AE1, KE1 are formed over the whole surfaces. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an electrochemical device such as a battery or an electric double layer capacitor (EDLC).

  The technique regarding the electrochemical device (battery, EDLC) using the conventional winding electrode is disclosed by patent documents 1-11. Patent Document 1 discloses a technique related to a metal foil spacer, Patent Document 2 discloses a technique related to a resin spacer, Patent Document 3 discloses a technique related to application of an insulating tape, and Patent Document 4 discloses terminal attachment to a winding end surface. Patent Document 5 discloses a technique related to protective layer formation, Patent Document 6 discloses a technique related to metal band attachment, Patent Document 7 discloses a technique related to insulating spacer film attachment, and Patent Document 8 discloses A technique for separating the separator with a spacer is disclosed, Patent Document 9 discloses a technique using an insulating spacer layer, and Patent Document 10 and Patent Document 11 disclose a technique using a metal spacer band.

  In many wound-type electrochemical devices, a pair of strip electrodes and a pair of strip separators are alternately stacked. Activated carbon is coated with a binder resin on the upper and lower surfaces of one strip electrode. The stacked ones are wound around the core, and the ends in the width direction of the wound electrodes are directly welded and used directly as the extraction electrode. Here, the reason why the belt-like electrode is directly welded is that when an extra terminal is attached thereto, the impedance becomes high.

JP 2002-298922 A JP 2000-021436 A JP 2005-235414 A JP-A-2005-347608 JP 2007-095656 A JP 2007-335814 A JP 2008-193010 A JP 05-109435 A Japanese Patent Laid-Open No. 07-130389 Japanese Patent Laid-Open No. 11-135100 Japanese Patent Laid-Open No. 11-283606

  However, when the end in the width direction of the wound body is simply used as the extraction electrode, a gap is formed between the end portions in the width direction of the strip electrode. Due to the presence of this gap, the band-shaped electrode is deformed and the impedance characteristics are deteriorated or varied.

  This invention is made | formed in view of such a problem, and it aims at providing the winding type electrochemical device excellent in the impedance characteristic and the thermal radiation characteristic.

  In order to solve the above-described problem, an electrochemical device according to the present invention includes a wound strip-shaped laminate and an enclosure that houses the laminate together with an electrolyte solution, and the strip-shaped laminate is a pair. A strip-shaped electrode and a pair of separators sandwiching one of the strip-shaped electrodes, each of the strip-shaped electrodes having a strip-shaped main metal foil and an active material layer provided on the main metal foil. In the chemical device, the positions of adjacent ones of the strip-shaped main metal foil are shifted along the width direction, and the active material layer is formed on one side of each of the main metal foils in a region where they do not overlap. An exposed region that is not formed is set, and the active material layer is formed on each of the other side surfaces.

  According to the present invention, since the active material layer is formed in the region on the other surface side where the main metal foil does not overlap, the region is mechanically strengthened and deformation thereof is suppressed. Therefore, the impedance change between the terminals resulting from the deformation is suppressed. In particular, when the pressing process is performed in the thickness direction in order to increase the density of the active material layer, the exposed region is likely to be deformed. However, in the present invention, the deformation is suppressed.

  Further, since the active material layer is not formed on the one surface side facing the other surface side, the active material layer on the other surface side does not effectively contribute to charge accumulation. Therefore, when the main metal foil in the exposed region is welded to a terminal electrode plate or the like, there is an advantage that even if the active material layer in such a region is damaged, element characteristics such as impedance characteristics are not affected.

  The other surface is located farther from the central axis of winding than the corresponding one surface. That is, the other surface is located outside the one surface during winding. An active material layer is formed on the other surface, and the active material layer shrinks slightly during formation, so that tensile stress remains inside. Therefore, when the strip electrode is wound with this outside, the winding is performed against the tensile stress, and the strip electrode can be wound with a large force, and the adhesion with the adjacent material of the strip electrode. And the strength of the wound laminate is increased.

  Further, an auxiliary metal foil is provided on the one surface of the main metal foil. That is, the auxiliary metal foil can further increase the mechanical strength of the exposed region where the main metal foil does not overlap. Moreover, since the auxiliary metal foil narrows the movable range in the radial direction in the exposed region of the main metal foil together with the active material layer on the other surface side, it is possible to suppress the impedance change due to the displacement of the main metal foil. In addition, since the cross-sectional area in the stacking direction is larger than that of the main metal foil alone, a bonding area is increased when an electrode plate or the like is welded thereto. When the contact area with the electrode plate increases, these contact resistances can be reduced, the internal resistance of the element can be suppressed, and the output is improved.

  The thickness of the auxiliary metal foil is preferably the same as the thickness of the active material layer. In this case, even when the pressing process is performed in the thickness direction, the active material layer and the auxiliary metal foil are evenly pressurized, so that the deformation of the main metal foil provided with these can be suppressed, and the impedance accompanying the deformation Change can be suppressed.

  There are a plurality of auxiliary metal foils, and these auxiliary metal foils are provided intermittently along the longitudinal direction, and each of the auxiliary metal foils has one longitudinal direction relative to the main metal foil. It is preferable that welding is performed only at the positions. In this case, stress is difficult to accumulate inside the auxiliary metal foil. In other words, the gap between the auxiliary metal foils can absorb the twist caused by the difference between the inner and outer circumferences of the main metal foil and the auxiliary metal foil during winding, and one place in the longitudinal direction (circumferential direction after winding) Therefore, it is possible to suppress the deformation of the structure around which the laminate is wound, and to provide an electrochemical device with little impedance variation and quality error.

  The electrochemical device of the present invention is superior in impedance characteristics.

It is a disassembled perspective view of the laminated body used for a winding type electrochemical device. It is a perspective view of the laminated body used for a wound-type electrochemical device. It is a perspective view of the laminated body wound around the core. It is a longitudinal cross-sectional view of the electrochemical device before the electrode plate used as a lid | cover is attached. It is a perspective view of the electrochemical device at the time of electrode plate attachment used as a lid. It is a longitudinal cross-sectional view of the electrochemical device after the electrode plate used as a lid | cover is attached. It is sectional drawing of the laminated body for demonstrating a laminated structure in detail. It is a perspective view of a part of a laminated body wound. It is a perspective view of a part of a laminated body wound. It is a perspective view of a part of a laminated body wound. It is sectional drawing of the electrode structure further provided with auxiliary metal foil. It is the perspective view (A) and sectional drawing (B) of an electrode structure further provided with auxiliary metal foil. It is the perspective view (A) and sectional drawing (B) of an electrode structure further provided with auxiliary metal foil.

  Hereinafter, the electrochemical device according to the embodiment will be described. The same reference numerals are used for the same elements, and redundant description is omitted.

  FIG. 1 is an exploded perspective view of a laminate used for a wound electrochemical device, and FIG. 2 is a perspective view of the laminate used for a wound electrochemical device. The electrochemical device is an electric double layer capacitor (EDLC), but this structure can also be applied to a normal battery.

  This laminated body is strip-shaped, and has a pair of strip-shaped electrodes (anode electrode A, cathode electrode K) and a pair of separators S1 and S2 sandwiching one of the strip-shaped electrodes (cathode electrode K in this figure). . In the following description, a three-dimensional orthogonal coordinate system is set, the width direction of the strip electrode is taken as the Z-axis direction, the thickness direction is taken as the X-axis direction, and the longitudinal direction perpendicular to both is taken as the Y-axis.

  The strip electrode constituting the anode electrode A has a strip-shaped main metal foil A1 and a pair of active material layers AE1 and AE2 provided on both surfaces of the main metal foil A1. The strip electrode constituting the cathode electrode K has a strip-shaped main metal foil K2 and a pair of active material layers KE1 and KE2 provided on both surfaces of the main metal foil K2. The positions of adjacent ones of the strip-shaped main metal foils A1 and K2 are shifted along the width direction (Z-axis direction), and one side of each of the main metal foils A1 and K2 in a region where they do not overlap ( An exposed region (indicated by a dimension Z3 in FIG. 7) where the active material layers AE2 and KE2 are not formed is set on the lower surface side of FIG. 1, and the active material is formed on the other surface side (upper surface side in FIG. 1). Layers AE1 and KE1 are formed on the entire surface. That is, active material layers AE1 and KE1 are formed on the side opposite to the above-described exposed region.

  The exposed region extends along the longitudinal direction (Y axis) on the lower surface of the main metal foil A1. The exposed region extends along the longitudinal direction (Y axis) on the lower surface of the main metal foil K2. The exposed regions in the main metal foils A1 and K2 are separated along the Z-axis direction.

  The widths of the separators S1 and S2 are equal to each other, and the widths of the active material layers AE1 and KE1 on the upper surface are also equal to each other. The widths of the active material layers AE2 and KE2 on the lower surface are also equal to each other. The widths of the separators S1 and S2 are slightly wider than the widths of the narrow active material layers AE2 and KE2. The above relationship is maintained even after the laminate is wound, but after the winding, the main metal foils A1 and K2 are electrode plates L1 serving as lids provided at both ends in the width direction (Z-axis direction). , L2 respectively (see FIG. 6). The main metal foils A1 and K2 are welded to the electrode plates L1 and L2, respectively, and in particular, laser welding (see FIG. 6).

  In addition, what is necessary is just to use a well-known thing as a material of above-mentioned separator S1, S2, active material layer AE1, AE2, KE1, KE2, and metal foil A1, K2. Examples of these materials are shown below, but the present invention is not limited to these materials.

  Separator S1, S2 consists of a nonwoven fabric or a porous film containing polyolefin resin of 10% or more of weight ratio, for example. The polarizable electrode and the separator can be bonded together by applying pressure to the pair of polarizable electrodes in a temperature environment equal to or higher than the softening point temperature of the polyolefin resin. A cellulose nonwoven fabric or an aramid fiber nonwoven fabric can also be used as the separator.

  The active material layers AE1, AE2, KE1, and KE2 are polarizable electrodes. This polarizable electrode is made of a porous material, and is manufactured by mixing activated carbon with a binder resin. Examples of the binder resin include fluorine-containing polymer compounds such as polytetrafluoroethylene, and rubber-based polymer compounds such as styrene butadiene rubber. If necessary, carbon black, carbon nanotubes, fine particles of graphite, or fine fibers can be blended as a conductive aid. At the time of manufacture, these materials are emitted from the nozzle and applied to both sides of the main metal foil.

  The main metal foils A1 and K2 are current collectors, and aluminum foil or copper foil whose surface is roughened by etching can be used. As an electrode manufacturing method, there are innumerable methods such as adding a conductive additive and a binder to activated carbon to form a sheet and adhering it to the collector, and a method of applying activated carbon to a collector in a slurry.

  FIG. 3 is a perspective view of the laminate wound around the winding core.

  The laminated body shown in FIGS. 1 and 2 is wound around a core B having an outer surface having a cylindrical surface, and the electrochemical device body 10 is formed from these. The central axis of the winding core B is the Z axis, and the laminate is wound around the Z axis. As the distance from the axial center increases, anode electrodes A and cathode electrodes K are alternately stacked, and separators S1 and S2 are interposed therebetween. The ends of the main metal foils A1 and K2 are located at the ends in the Z-axis direction. At the positive end of the Z-axis, the main metal foil K2 (see FIG. 1) of the cathode electrode K is disposed adjacent to the radial direction in the XZ plane. At the end in the negative direction of the Z-axis, the main metal foil A1 (see FIG. 1) of the anode A is adjacently disposed along the radial direction in the XZ plane.

  FIG. 4 is a vertical cross-sectional view (XZ cross-sectional view) of the electrochemical device before attachment of the electrode plate serving as a lid.

  In the production of this electrochemical device, the electrochemical device body 10 is inserted into the cylindrical body H so that the respective axes coincide with each other, and both end openings of the cylindrical body H are covered by electrode plates L1 and L2 which are lids. Although the sealing is performed sequentially, the electrolytic solution is introduced into the enclosure before sealing one of the electrode plates L1. An adhesive can also be used for this sealing. A surrounding body is constituted by the cylindrical body H and the electrode plates L1 and L2. The shape of the cylindrical body H may be a cylindrical shape as well as a rectangular cylindrical shape. Further, the outer surface shape of the core B can be a rectangular tube surface. As a material for the core B and the cylinder H, various materials can be used as long as they can prevent a short circuit between the anode electrode and the cathode electrode. For example, an insulator can be used. The structure of the core B or the cylinder H may be a structure in which a metal cylinder is joined to both ends of the insulator cylinder.

  FIG. 5 is a perspective view of the electrochemical device when the electrode plate serving as a lid is attached, and FIG. 6 is a longitudinal sectional view (XZ sectional view) of the electrochemical device after the electrode plate serving as a lid is attached.

  This electrochemical device includes a wound belt-like laminated body and an enclosure that houses the laminated body together with the electrolytic solution LQ. As described above, the enclosure includes the cylinder H and the electrode plates L1 and L2. In order to electrically connect the electrode plates L1 and L2 and the main metal foils A1 and K2, respectively, the electrode plates L1 and L2 are irradiated with the laser beam LB from the outside, the irradiation positions are melted, and the inner positions thereof are respectively positioned. The main metal foils A1 and K2 and the electrode plates L1 and L2 are joined. A concave portion D is formed at the irradiation position of the laser beam LB. The plurality of recesses D are formed radially in the XY plane. In addition, instead of the laser beam LB, a current is applied to the electrode plates L1 and L2 at a high voltage, so that the current supply portions are melted. Similarly, the main metal foils A1 and K2 and the electrode plates L1 respectively located inside these portions. , L2 can also be joined. Note that an electrolytic solution LQ is sealed inside the enclosure.

  As the electrolytic solution LQ, an aqueous solution type and an organic type are known. Examples of the solvent for the organic electrolyte include propylene carbonate and acetonitrile, and examples of the solute include ammonium salt, amine salt, and amidine salt.

  FIG. 7 is a cross-sectional view of a laminated body for explaining the laminated structure in detail.

  Explaining the dimensions in the Z-axis direction, the dimension Z1 is the width of the main metal foils A1 and K2, the dimension Z2 is the width of the active material layers AE2 and KE2 on the narrow side, the dimension Z3 is the width of the exposed region (Z1-Z2), The dimension Z4 indicates the distance that the separator protrudes from the active material layers AE2 and KE2 in the Z direction, and the dimension Z6 indicates the width of the separators S1 and S2.

  Explaining the dimensions in the X-axis direction, the dimension X1 is the thickness of the main metal foils A1 and K2, the dimension X2 is the thickness of the active material layers AE1, AE2, KE1, and KE2, and the dimension X3 is the thickness of the separators S1 and S2. is there.

  The preferred range of each dimension is as follows.

10mm ≦ Z1 ≦ 1000mm
5mm ≦ Z2 ≦ 995mm
2mm ≦ Z3 ≦ 50mm
1mm ≦ Z4 ≦ 10mm
7mm ≦ Z6 ≦ 997mm
10 μm ≦ X1 ≦ 200 μm
10 μm ≦ X2 ≦ 500 μm
10 μm ≦ X3 ≦ 50 μm
Regarding the above-mentioned range, the range of Z1 indicates a realistic width of the electrode foil. The range of Z2 indicates the width (electrode width) of the active material layer that can be actually applied. Since the region defined by Z3 does not affect the element function, it is preferable that the region is small from the viewpoint of miniaturization. It can be flat and the width can be set arbitrarily. However, since there is a risk of damaging the active material layer that functions effectively below the lower limit value during welding, the upper limit value is preferably greater than or equal to the upper limit value. It is preferable that

  Z4 defines the amount of protrusion of the separator, and this range does not affect the electrical characteristics and has a margin that prevents the separated metal foil from contacting. Since Z6 is the width of the separator, it was set as a value obtained by adding 2 mm to Z2.

  The range of X1 is a realistic thickness range of the current collector, and a thicker one is preferable from the viewpoint of low resistance and high strength, but the degree of integration per unit volume is low and many Charges cannot be accumulated. In order to prevent damage due to relatively low resistance, a thickness equal to or greater than the lower limit value is suitable, and the thickness that can sufficiently maintain strength with low resistance without greatly degrading the integration degree is a value equal to or less than the above upper limit value. is there.

  The range of X2 defines the realistic thickness range of the active material layer, and since the contact resistance of the electrode activated carbon particles is reduced, there is an advantage that the lower the internal resistance in the thickness direction, the lower the above upper limit value. However, if it is too thin, the function as the active material layer is not sufficient, so that it is preferably not less than the above lower limit value.

  The range of X3 is a realistic thickness range of the separator, and since the thinner one has the advantage that the internal resistance in the thickness direction becomes smaller, it is preferably not more than the above upper limit value. Is not sufficient, and the active material layer separated by the separator is effectively short-circuited.

  According to the electrochemical device described above, since the active material layers AE1 and KE1 are formed in the region on the other surface side (the upper surface side in FIG. 7) where the main metal foil does not overlap, the region is mechanically strengthened. And the deformation is suppressed. Therefore, the impedance change between the terminals resulting from the deformation is suppressed. In particular, when the pressing process is performed in the thickness direction in order to increase the density of the active material layer, the exposed region is likely to be deformed, but in the present embodiment, the deformation is suppressed.

  Further, since the active material layers AE2 and KE2 are not formed on the one surface side (the lower surface side in FIG. 7) opposite to the other surface side (the upper surface side in FIG. 7), the active material layers AE1 on the other surface side are not formed. KE1 does not contribute to charge accumulation effectively. Therefore, when the main metal foils A1 and K2 in the exposed region (Z3) are welded to a terminal electrode plate or the like, even if the active material layers AE1 and KE1 in the region are damaged, the element characteristics such as impedance characteristics are affected. There is an advantage of not giving.

  Moreover, since the active material layers AE1 and KE1 slightly narrow the movable range in the radial direction (X-axis direction in FIG. 7) in the exposed regions of the main metal foils A1 and K2, the positions of the main metal foils A1 and K2 in the X-axis direction Impedance change due to deviation can be suppressed to some extent.

  Further, the other surface (the upper surfaces of A1 and K2 in FIG. 7) is located farther from the center axis (Z-axis) of winding than the corresponding one surface (the lower surfaces of A1 and K2 in FIG. 7). To do. That is, the other surface (the upper surfaces of A1 and K2 in FIG. 7) is located outside the one surface (the lower surfaces of A1 and K2 in FIG. 7) during winding. Active material layers AE1 and KE1 are formed on the other surface (the upper surfaces of A1 and K2 in FIG. 7), and the active material layer shrinks slightly during formation, so that tensile stress remains inside. Therefore, when the strip electrode is wound with this outside, the winding is performed against the tensile stress, and the strip electrode can be wound with a large force, and the adhesion with the adjacent material of the strip electrode. And the strength of the wound laminate is increased.

  FIG. 8 is a perspective view of a part of the wound laminated body according to the first embodiment. This figure shows the shape of the end portion in the Z-axis direction of the anode electrode or the cathode electrode.

  The active material layer AE2 or KE2 is not formed in the exposed region. Further, the other surface (the upper surfaces of A1 and K2 in FIG. 7) is located outside the one surface (the lower surfaces of A1 and K2 in FIG. 7) during winding. The central axis of winding is the Z axis and is located at the center of curvature of the main metal foil A1 or K2.

  FIG. 9 is a perspective view of a part of a wound laminated body according to the second embodiment.

  In the above, the active material layer AE1 (KE1) is formed on the entire surface of the main metal foil A1 (K2). However, the active material layer AE1 (KE1) may not be formed in a part of the region RK. Good. The cutout region RK has a slit shape extending along the Z-axis from the end portion in the Z-axis direction of the main metal foil A1 (K2). Even in such a case, the active material layer formed in the above-described exposed region AE1 (KE1) reinforces the main metal foil A1 (K2).

  FIG. 10 is a perspective view of a part of a rolled laminate according to the third embodiment.

  In the first embodiment, the active material layer AE1 (KE1) is formed on the entire surface of the main metal foil A1 (K2). However, in the third embodiment, the active material layer AE1 (KE1) is a part of the active metal layer AE1 (KE1). It is not formed in the region RK. The outer edge shape of the cutout region RK is a part of an arc extending from the end of the main metal foil A1 (K2) in the Z-axis direction. Even in this case, the active material layer AE1 ( KE1) reinforces the main metal foil A1 (K2).

  FIG. 11 is a cross-sectional view of an electrode structure in which auxiliary metal foils T1 and T2 are further provided on the exposed region.

  Auxiliary metal foils T1 and T2 are provided on the one surface (the lower surface in FIG. 11) of the main metal foils A1 and K2. That is, the auxiliary metal foils T1 and T2 can further increase the mechanical strength of the exposed region where the main metal foils A1 and K2 do not overlap. Further, the auxiliary metal foils T1 and T2, together with the active material layers AE1 and KE1 on the other side (the upper surface in FIG. 11), narrows the movable range in the radial direction in the exposed areas of the main metal foils A1 and K2, so Impedance changes due to radial displacement of A1 and K2 can be suppressed. In addition, since the cross-sectional area in the stacking direction is larger than the case of the main metal foils A1 and K2 alone, when an electrode plate or the like is welded to the main metal foils A1 and K2, the joining area becomes large. When the contact area with the electrode plate increases, these contact resistances can be reduced, the internal resistance of the element can be suppressed, and the output is improved.

  Further, heat can be radiated through the contact part. Therefore, this electrochemical device is superior in impedance characteristics and heat dissipation characteristics. From the above viewpoint, the thickness of the auxiliary metal foils T1, T2 (X4) is preferably as large as possible.

  Moreover, it is preferable that the thickness of auxiliary metal foil T1, T2 is the same as the thickness of active material layer AE2, KE2. In this case, even when the pressing process is performed in the thickness direction, the active material layer and the auxiliary metal foil are evenly pressurized, so that the deformation of the main metal foil provided with these can be suppressed, and the impedance accompanying the deformation Change can be suppressed. Note that “same” includes an error within ± 5% with respect to one thickness.

  12 and 13 are a perspective view (A) and a sectional view (B) of an electrode structure further provided with an auxiliary metal foil.

In each of the anode electrode and the cathode electrode, there are a plurality of auxiliary metal foils T1, T2, and these auxiliary metal foils T1, T2 are provided intermittently along the longitudinal direction, and each auxiliary metal foil T1, T2 is only one position P in the longitudinal direction (Y-axis in FIG. 11: circumferential direction after winding) with respect to the main metal foils A1 and K2 (in this example, one point on the side from the winding start position). It is preferable to be welded. In this case, stress is difficult to accumulate inside the auxiliary metal foils T1, T2. In other words, the gap between the auxiliary metal foil T1 (or T2) can absorb the twist caused by the difference between the inner and outer circumferences of the main metal foil A1 (K2) and the auxiliary metal foil T1 (T2) during winding, Since welding is performed only at one position P in the longitudinal direction (circumferential direction after winding), it is possible to suppress deformation of the structure around which the laminate is wound, and electrochemical characteristics with less impedance variation and quality error. A device can be provided.

  As shown in the cross-sectional views of FIGS. 12B and 13B, the auxiliary metal foils T1 and T2 are partially melted by being irradiated with the laser beam LB from the X-axis direction of FIG. , Mixed with the lower main metal foil A1 (K2), fixed during cooling, and these are electrically connected. Laser beam irradiation traces P are formed on the surfaces of the auxiliary metal foils T1 and T2, which constitute a slight recess. In one auxiliary metal foil T1 (T2), it is preferable that the welding mark P is located on the winding start side of the strip electrode in terms of not accumulating stress, but may be another position. Moreover, as long as welding is performed only at one location in the circumferential direction, the number of weld locations may be two per auxiliary metal foil T1 (T2). That is, in FIG. 12B and FIG. 13B, even when two welding traces P are adjacent to each other at the same coordinate position on the Y axis, the longitudinal direction (circumferential direction) is one. It is welded only at the location.

  The material of the auxiliary metal foils T1, T2 is preferably the same as the material of the main metal foils A1, K2. For example, both are made of aluminum or copper. In this case, both materials can be easily welded, and since there is no potential difference between the materials at the time of contact, there is an advantage that characteristics are stabilized. The auxiliary metal foils T1 and T2 and the main metal foils A1 and K2 are electrically connected and preferably welded (welded) with laser light or the like. It is preferable to perform sequentially while rotating. This is because stress is hardly generated between them.

  Also, the auxiliary metal foil T1. When T2 is continuously or intermittently welded to the main metal foils A1 and K2 along the longitudinal direction of the main metal foils A1 and K2 (which becomes the circumferential direction after winding), these are strengthened. Can be fixed to.

  The active material layers AE2 and KE2 and the auxiliary metal foils T1 and T2 may be physically separated from each other, but they may be slightly in contact with each other.

  As described above, according to the above-described structure, deformation of the main metal foil at the end in the Z-axis direction is suppressed, so that occurrence of a portion that is not welded to the terminal is suppressed, and impedance characteristics are improved. In addition, when the auxiliary electrode foil having the same thickness as the active material layer is welded to the uncoated portion of the active material layer, the entire surface of the main metal foil is flat, so that during the press process in the thickness direction , Pressure is evenly applied to these, and irregular deformation is suppressed.

A ... anode electrode, A1, K2 ... main metal foil, AE1, AE2, KE1, KE2 ... active material layer, K ... cathode electrode, T1, T2 ... auxiliary metal foil.

Claims (5)

A wound strip-shaped laminate, and an enclosure that houses the laminate together with an electrolyte solution, the strip-shaped laminate having a pair of strip electrodes and a pair of separators sandwiching one of the strip electrodes. Each of the strip-shaped electrodes is a wound-type electrochemical device having a strip-shaped main metal foil and an active material layer provided on the main metal foil.
Adjacent ones of the strip-shaped main metal foils are shifted in the width direction, and the active material layer is not formed on one side of each of the main metal foils in a region where they do not overlap. An exposed region is set, and the active material layer is formed on each other surface side.
An electrochemical device characterized by that. The other surface is located farther from the central axis of winding than the corresponding one surface.
The electrochemical device according to claim 1. An auxiliary metal foil is provided on the one surface of the main metal foil.
The electrochemical device according to claim 1 or 2, characterized in that The thickness of the auxiliary metal foil is the same as the thickness of the active material layer.
The electrochemical device according to any one of claims 1 to 3, wherein: There are a plurality of auxiliary metal foils, and these auxiliary metal foils are provided intermittently along the longitudinal direction, and each of the auxiliary metal foils has one longitudinal direction relative to the main metal foil. Welded only at the location of the location,
The electrochemical device according to any one of claims 1 to 4, wherein:

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