JP2011228400A - Electrochemical device and manufacturing method for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wound type electrochemical device restrained in characteristics fluctuations and a manufacturing method for the same.SOLUTION: An electrochemical device comprises auxiliary metal parts T1 and T2 provided around the axes of winding at one end along the axes of winding of an anode electrode A and a cathode electrode K, a separator S1 intervening between the anode electrode A and the cathode electrode K, and a thermoplastic resin disposed between the auxiliary metal parts T1 and T2 and active substance layers AE1 and KE1, wherein reinforced resin layers TC1 and TC2 thinner than the auxiliary metal parts T1 and T2 and not in contact with the separator S1 but in contact with both the flanks of the auxiliary metal parts T1 and T2 and the flanks of the active substance layers AE1 and KE1.

Description

  The present invention relates to an electrochemical device such as an electric double layer capacitor (EDLC) and a manufacturing method thereof.

  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 applied to the upper and lower surfaces of one strip electrode with a binder resin. 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.

  FIG. 9 is a longitudinal sectional view of an electrochemical device for comparison. In FIG. 9, the electrochemical device body 10 shows the side surface state as it is, not the cross section, for clarification of the description of the structure.

  The enclosure includes a cylindrical body H and electrode plates L1 and L2, and the electrochemical device main body 10 is accommodated in the enclosure together with the electrolyte LQ. The electrode plate L2 located below the drawing is formed integrally with the cylinder H, and the electrode plate L1 located above is embedded in the resin lid material L1R, and the resin lid material L1R. However, the opening of the cylinder H is closed. Metal electrode tabs 10L1 and 10L2 respectively constituting both terminals of the capacitor extend from the vertical end of the device body 10 in the drawing, and these contact the electrode plates L1 and L2, respectively, and electrically It is connected to the.

  In the case of an electrochemical device having such a structure, the metal electrode tabs 10L1 and 10L2 have a slight resistance, which contributes to an increase in internal resistance. In general, the internal resistance tends to increase as the electrochemical device deteriorates. In this case, there is a problem that the voltage applied to the external load decreases. Therefore, in order to reduce the internal resistance, it is conceivable to weld the end portion of the electrochemical device body directly to the electrode plate without using the metal electrode tab.

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 of the electrochemical device body is directly welded to the electrode plate, there is a problem that the characteristics vary.

  The inventor of the present application diligently studied the variation in characteristics, and in the case of direct welding, heat is transmitted from the electrode plate to the end of the device body, and pressure is applied, which is caused by the heat and pressure. As a result, it has been found that the end of the electrochemical device body is deformed and its characteristics vary greatly.

  This invention is made | formed in view of such a problem, and it aims at providing the winding type electrochemical device by which the dispersion | variation in a characteristic is suppressed, and its manufacturing method.

  In order to solve the above-described problem, a wound electrochemical device according to the present invention includes an enclosure, an electrochemical device body enclosed in the enclosure, and a wound positive electrode strip electrode, An electrochemical device body having a negative electrode strip wound so as to face the positive electrode strip, and a separator interposed between the positive electrode strip and the negative electrode strip.

  The positive electrode strip electrode includes a wound positive electrode main metal foil, a positive electrode active material layer formed around the winding axis of the positive electrode main metal foil, and the positive electrode main metal foil. A positive side auxiliary metal part provided on the positive side main metal foil along the winding axis at one end side along the winding axis, and between the positive side auxiliary metal part and the positive side active material layer It consists of a provided positive electrode side thermoplastic resin, is thinner than the positive electrode side auxiliary metal part, does not contact the separator, and contacts both the side surface of the positive electrode side auxiliary metal part and the side surface of the positive electrode side active material layer A positive-side reinforcing resin layer.

  Similarly, the negative electrode strip electrode includes a wound negative electrode side main metal foil, a negative electrode active material layer formed around the winding axis of the negative electrode main metal foil, and the negative electrode main layer. On the other end side along the winding axis of the metal foil, the negative side auxiliary metal part provided on the negative side main metal foil along the winding axis, the negative side auxiliary metal part, and the negative electrode side active material layer Between the negative electrode side auxiliary metal portion and the side surface of the negative electrode side auxiliary metal portion and the side surface of the negative electrode side active material layer. And a negative electrode side reinforcing resin layer that is in contact with both.

  According to this electrochemical device, since the auxiliary metal part is provided in the main metal foil of the positive electrode and the negative electrode, the mechanical strength of the part increases and the auxiliary metal part extends in the radial direction of each strip electrode. Therefore, the change in capacity between them is suppressed. In addition, since a reinforcing resin layer made of a thermoplastic resin and in contact with both side surfaces is provided between the auxiliary metal part of the positive electrode and the negative electrode and the active material layer, the mechanical strength of the portion where this is reliably applied is provided. In addition, the relative movement between the auxiliary metal part and the material layer is restricted, and variations in the characteristics of the electrochemical device are further suppressed.

  In addition, since the reinforcing resin layer is thinner than the auxiliary metal portion and does not contact the separator, heat is not directly transferred from the reinforcing resin layer to the separator, and the separator is protected from heat. In other words, the variation in characteristics due to the deterioration of the separator can be further suppressed. This structure is particularly useful when adopting a resin separator such as polyacrylonitrile having a low internal resistance. Recently, as a measure for lowering resistance (internal resistance), there are cases where measures are taken to reduce the thickness of the electrode (active material layer). If the auxiliary metal foil is also thickened at the same time, the strength becomes very weak. However, the presence of the resin layer makes it possible to maintain high strength even with low resistance.

  In the electrochemical device according to the present invention, one end in the winding axis direction of the positive electrode strip electrode and the negative electrode strip electrode is directly welded to an electrode plate constituting the lid of the enclosure. Features.

  In this case, since each strip electrode is directly welded to the electrode plate, the internal resistance can be reduced, but the resistance to heat and pressure during welding is also improved, so the characteristics as described above. The variation of is suppressed.

  The enclosure according to the present invention includes a metal cylinder, an insulating ring interposed between the electrode plate and the cylinder, a peripheral portion of the electrode plate, and an outer surface of the cylinder. And a heat-shrinkable tube for coating.

  In order to weld directly to the electrode plate, it is necessary to be made of metal. However, if the cylinder is also made of metal, the positive and negative electrodes are short-circuited, so an insulating ring is interposed between the cylinder and the electrode plate. In particular, these can be fixed by using heat-shrinkable tubes.

  Further, in the present invention, the enclosure includes a metal cylinder sealed by the electrode plate, and a part of the cylinder is recessed from the outer periphery toward the center, so that the cylinder It is characterized by comprising a narrowing part for fixing the inner surface of the body in contact with the outer surface of the electrochemical device body.

  As described above, since the axial portion and the radial movement of the internal electrochemical device main body are restricted due to the narrowing portion, a change in characteristics due to vibration or the like is suppressed.

  In addition, the method for producing an electrochemical device according to the present invention includes (A) a step of preparing the positive electrode strip electrode on which the positive electrode side active material layer and the positive electrode side auxiliary metal part are formed, and (B) the negative electrode. A step of preparing the negative electrode strip electrode in which the side active material layer and the negative electrode side auxiliary metal portion are respectively formed; and (C) a positive electrode side heat between the positive electrode side auxiliary metal portion and the positive electrode side active material layer. A step of arranging a plastic resin, (D) a step of arranging a negative electrode side thermoplastic resin between the negative electrode side auxiliary metal part and the negative electrode side active material layer, and (E) the positive electrode side thermoplastic resin It contacts both the side surface of the positive electrode side auxiliary metal part and the side surface of the positive electrode side active material layer, and the negative electrode side thermoplastic resin is in contact with the side surface of the negative electrode side auxiliary metal part and the side surface of the negative electrode side active material layer. Said positive side thermoplastic resin and so as to be in contact with both Heating the negative side thermoplastic resin; and (F) cooling and solidifying the positive side thermoplastic resin and the negative side thermoplastic resin to form the positive side reinforcing resin layer and the negative side reinforcing resin layer. And a step of performing.

  According to this method, by heating the thermoplastic resin, the above-mentioned reinforcing resin layer is formed, so that it can be easily brought into contact with the active material layer of each electrode and the side surfaces of the auxiliary metal part, It becomes easy to manufacture an electrochemical device in which variation in characteristics is suppressed.

  According to the wound electrochemical device of the present invention and the manufacturing method thereof, variation in characteristics can be suppressed.

It is a perspective view of the electrochemical device which concerns on embodiment. It is II-II arrow sectional drawing of the electrochemical device shown in FIG. It is sectional drawing of the electrochemical device intermediate body for demonstrating the manufacturing process of an electrochemical device. It is a top view of the electrochemical device main body which expands and shows the rolled electrochemical device main body partially. It is VV arrow sectional drawing of the electrochemical device shown in FIG. It is a figure for demonstrating the formation process of the reinforcement resin layer by melting of a thermoplastic resin. It is a figure for demonstrating the effect of a reinforcement resin layer. It is a figure for demonstrating the dimension of the component of a strip electrode. It is a longitudinal cross-sectional view of the electrochemical device for a comparison.

  Hereinafter, the electrochemical device and the manufacturing method thereof 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 a perspective view of a wound electrochemical device according to an embodiment, and FIG. 2 is a cross-sectional view taken along the line II-II of the electrochemical device shown in FIG. 2 and 3, the electrochemical device body 10 shows the side surface state as it is, not the cross section, for the sake of clarifying the structure. Further, a three-dimensional orthogonal coordinate system is set as shown in the figure, with the winding axis of the electrode of the electrochemical device as the Z axis and the two axes perpendicular to the Z axis as the X axis and the Y axis.

  The electrochemical device 100 includes an enclosure and an electrochemical device main body 10 enclosed in the enclosure, and the enclosure is filled with an electrolyte LQ. The enclosure includes a metal cylinder H, an insulating ring H1 interposed between the electrode plate L1 and the cylinder H, a peripheral portion of the electrode plate L1, and an outer surface of the cylinder H. The shrinkable tube 20 is provided.

  Since the electrode plates L1 and L2 and the electrochemical device body 10 are directly welded, these are made of metal. The cylinder H is also made of metal. Since the insulating ring H1 is interposed between the cylindrical body H and the electrode plate L2, it is possible to prevent the positive and negative electrodes (electrode plates L1, L2) from being short-circuited. Moreover, the cylindrical body H, the insulating ring H1, and the electrode plate L1 are fixed to each other by using the heat shrinkable tube 20.

  One opening of the cylindrical body H is closed by the electrode plate L1, while the other opening is closed by the electrode plate L2. The cylindrical body H and the other electrode plate L2 are integrally formed. Both ends of the electrochemical device body 10 in the winding axis (Z-axis) direction are fixed to the electrode plates L1 and L2, respectively. This fixing is performed by welding, and a welded portion D is shown in FIG. The welded portion D is formed by laser welding, and is formed by irradiating the electrode plates L1 and L2 with laser light. The plurality of irradiation spot positions of the laser beam are scattered in a radial manner along a direction extending in the radial direction from the Z axis serving as a winding axis.

  Further, as shown in FIG. 5, the electrochemical device body 10 includes a positive electrode strip electrode A and a negative electrode strip electrode K, and one end portion in the winding axis (Z axis) direction is a lid of the enclosure. Are welded directly to the electrode plates L1, L2 by the welded portion D.

  Further, the enclosure includes a metal cylinder H sealed by the electrode plate L1, and a part of the cylinder H includes a narrowing portion SB. The narrowed portion SB is recessed from the outer periphery toward the center, thereby fixing the inner surface of the cylindrical body H in contact with the outer surface of the electrochemical device body 10.

  In this manner, since the narrowed portion SB is provided, movement of the internal electrochemical device body 10 in the axial direction and the radial direction is restricted, so that a change in characteristics due to vibration or the like is suppressed.

  Since the end portions (auxiliary metal portions T1 and T2) of the respective strip electrodes A and K are directly welded to the electrode plates L1 and L2, the internal resistance is lower than that of the electrochemical device shown in FIG. Can be reduced.

  FIG. 3 is a cross-sectional view of the electrochemical device intermediate for explaining the manufacturing process of the electrochemical device.

  After the electrochemical device body 10 is inserted into the enclosure, the electrolytic solution LQ is filled into the cylindrical body H, and then the insulating ring H1 and the electrode plate L1 are disposed on one open end of the cylindrical body H ( FIG. 3 (A)). Subsequently, the electrode plates L1 and L2 are irradiated with the laser beam LB along the Z-axis direction, and the constituent materials at the laser beam irradiation positions of the electrode plates L1 and L2 are melted to form the melting portion D, and the electrochemical device The end of the main body 10 is fixed to the electrode plates L1 and L2. Thereafter, the heat-shrinkable tube 20 shown in FIG. 2 is fitted into the envelope and heated, whereby the heat-shrinkable tube 20 contracts and adheres closely to the envelope, and its constituent elements are fixed.

  Next, the electrochemical device body 10 will be described.

  FIG. 4 is a plan view of the electrochemical device body 10 showing a part of the rolled electrochemical device body, and FIG. 5 is a cross-sectional view taken along the line VV of the electrochemical device shown in FIG. is there.

  The electrochemical device body 10 is interposed between the wound positive electrode strip A, the negative electrode strip K wound so as to face the positive electrode strip A, and the positive electrode strip A and the negative electrode strip K. Separator S1. 4 and 5, the separator S2, the active material layer AE2, the main metal foil A1, the active material layer AE1, the separator S1, the active material are sequentially arranged in the positive direction of the X axis (the radial direction perpendicular to the winding axis). The material layer KE2, the main metal foil A2, and the active material layer KE1 are laminated.

  More specifically, the positive electrode strip electrode A serving as an anode is wound around the positive electrode side main metal foil A1 in the form of a wound belt and the winding axis (Z axis) of the positive electrode side main metal foil A1 (in this example, The positive electrode side active material layers AE1 and AE2 formed on both sides and the one end side (Z-axis positive direction position) along the winding axis (Z-axis) of the positive-side main metal foil A1 (see FIG. 4) Then, the positive side auxiliary metal part (metal foil) T1 (T1 (b)) provided on the positive side main metal foil A1 along the Y axis) and the positive side reinforcing resin layer TC1 (TC1 (b)). .

  The positive electrode side reinforcing resin layer TC1 (TC1 (b)) is made of a positive electrode side thermoplastic resin provided between the positive electrode side auxiliary metal portion T1 (T1 (b)) and the positive electrode side active material layer AE1 (AE2). Further, it is thinner than the positive electrode side auxiliary metal part T1 (T1 (b)) and does not contact the separator S1 (S2), and the side surface of the positive electrode side auxiliary metal part T1 (T1 (b)) and the positive electrode side active material layer AE1. It touches both sides.

  Similarly, the negative electrode strip electrode K serving as the cathode is formed along the wound strip-shaped negative electrode side main metal foil K2 and the winding axis of the negative electrode side main metal foil K2 (on both surfaces in this example). The negative side main metal along the winding axis on the other end side (Z-axis negative direction position) along the winding axis (Z axis) of the negative electrode side active material layers KE1 and KE2 and the negative side main metal foil K2 Between the negative electrode side auxiliary metal part (metal foil) T2 (T2 (b)) provided on the foil K2, and between the negative electrode side auxiliary metal part T2 (T2 (b)) and the negative electrode side active material layer KE1 (KE2). The negative electrode side reinforcing resin layer TC2 (TC2 (b)) provided is provided.

  The negative electrode side reinforcing resin layer TC2 (TC2 (b)) is made of a negative electrode side thermoplastic resin, is thinner than the negative electrode side auxiliary metal part T2 (T2 (b)), does not contact the separator S2 (S1), and It contacts both the side surface of the negative electrode side auxiliary metal portion T2 (T2 (b)) and the side surface of the negative electrode side active material layer KE1 (KE2).

  5, the electrode plate L1 and the auxiliary metal portion T1 (T1 (b)) are welded, and the electrode plate L2 and the auxiliary metal portion T2 (T2 (b)) are welded. In addition, each main metal foil A1, K2 is shifted in the end face position along the winding axis direction (width direction) Z, and the auxiliary metal portion T1 (T1 (b)) and T2 on the exposed region where they do not overlap. (T2 (b)) is formed.

  According to this electrochemical device, since the auxiliary metal portions T1 (T1 (b)) and T2 (T2 (b)) are provided on the main metal foils A1 and K2 of the positive electrode and the negative electrode, the machine of the part As the mechanical strength increases, the auxiliary metal portions T1 (T1 (b)) and T2 (T2 (b)) restrict the movement of the strip electrodes A and K in the radial direction. Is suppressed. Further, the auxiliary metal portions T1 (T1 (b)) and T2 (T2 (b)) of the positive electrode and the negative electrode and the active material layers AE1 (AE2) and KE1 (KE2) are both made of a thermoplastic resin. Since the reinforcing resin layers TC1 (TC1 (b)) and TC2 (TC2 (b)) that are in contact with the side surfaces of the auxiliary metal portions T1 (T1 (T1 (T1 ( b)), T2 (T2 (b)) and the relative movement between the material layers are restricted, and variations in characteristics of the electrochemical device are further suppressed.

  Further, each reinforcing resin layer TC1 (TC1 (b)), TC2 (TC2 (b)) is thinner than each auxiliary metal part T1 (T1 (b)), T2 (T2 (b)) adjacent to each other, Since the separators S1 and S2 are not in contact with each other, heat is not directly transferred from the reinforcing resin layers TC1 (TC1 (b)) and TC2 (TC2 (b)) to the separators S1 and S2. Separators S1 and S2 are protected from heat, and variations in characteristics due to deterioration of separators S1 and S2 can be further suppressed. Thus, in the electrochemical device which concerns on embodiment, since the tolerance with respect to the heat and pressure at the time of welding is improving, the dispersion | variation in a characteristic is suppressed.

  FIG. 6 is a diagram for explaining a step of forming a reinforcing resin layer by melting a thermoplastic resin.

  In the formation of the reinforcing resin layer TC1, the thermoplastic resin TC1 is first disposed on the surface of the main metal foil A1 between the active material layer AE1 and the auxiliary electrode layer T1 (FIG. 6A). Then, heat is applied to melt the resin, and the resin constituent material is moved in the direction of the arrow (FIG. 6B), and the side surface (XY surface) of the active material layer AE1 and the side surface (XY surface) of the auxiliary electrode layer T1 are moved. After the resin is brought into contact with both sides, it is cooled and solidified (FIG. 6C).

  FIG. 7 is a diagram for explaining the effect of the reinforcing resin layer.

  When the reinforcing resin layer TC1 exists as in the above-described embodiment (FIG. 7A), the reinforcing resin layer TC1 is an auxiliary metal against an impact (force F) in the Z-axis direction during laser light irradiation or the like. The variation and deformation of the distance between the portion T1 and the active material layer AE1 can be suppressed. On the other hand, when the reinforcing resin layer does not exist (FIG. 7B), the stress concentrates in the region between the auxiliary metal portion T1 and the active material layer AE1, and the bending occurs when the force F is applied.

  Further, at the time of irradiation with the laser beam LB, heat propagates as indicated by an arrow TML, and heat is directly transmitted to the separator S1 via the auxiliary metal portion T1 and the reinforcing resin layer TC1, and the separator S1 is damaged. There is a risk (FIG. 7C). On the other hand, in the structure according to the embodiment (FIG. 7A), since the thickness of the reinforcing resin layer TC1 is thin and there is a gap corresponding to X2-X5 between this and the separator S1, the separator S1 Direct heat is not transferred and the separator S1 is protected.

  In the formation of the reinforcing resin layer TC1 (b), the reinforcing resin layer TC1, the active material layer AE1, the auxiliary metal portion T1, and the separator S1 described above in FIG. 6 and FIG. ), Active material layer AE2, auxiliary metal portion T1 (b), and separator S2.

  In the formation of the reinforcing resin layer TC2, in FIG. 6 and FIG. 7, the reinforcing resin layer TC1, the active material layer AE1, the auxiliary metal portion T1, the main metal foil A1, and the separator S1 are respectively added to the reinforcing resin layer TC2. , Active material layer KE1, auxiliary metal portion T2, main metal foil K2, and separator S2.

  Similarly, in the formation of the reinforcing resin layer TC2 (b), the reinforcing resin layer TC1, the active material layer AE1, the auxiliary metal portion T1, and the main metal foil A1 described above in FIG. 6 and FIG. It will be read as TC2 (b), active material layer KE2, auxiliary metal portion T2 (b), and main metal foil K2.

  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, metal foil A1, K2, and reinforcement resin layer TC1, TC2. 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.

  The material of the reinforced resin layers TC1 and TC2 is a thermoplastic resin that is softened by heating and exhibits plasticity, and is a synthetic resin having a property of solidifying by cooling. That is, for the reinforcing resin layer, polyethylene, polypropylene, polystyrene, polyimide, ABS (acrylonitrile butadiene styrene) resin, vinyl chloride resin, methyl methacrylate resin, fluorine resin, polycarbonate, polyester resin, or the like can be used. These materials are easily available, do not react with ordinary electrolytes, and are chemically stable. In addition, these materials can become binder resin and can be impregnated with electrolyte solution. As the material of the reinforcing resin layers TC1 and TC2, a material used for the separator may be employed.

  When polypropylene is used as the resin, it has a feature that it melts at a high temperature (100 to 250 ° C.) and can be dried while heating at 200 ° C.

  Moreover, it is preferable that the material of auxiliary metal part (metal foil) T1, T2 is the same as the material of main metal foil 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 parts T1, T2 and the main metal foils A1, K2 are preferably electrically connected and welded (welded).

  Further, the auxiliary metal portion 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.

  In the above description, the auxiliary metal portion is provided on both surfaces of the main metal foil, but it may be provided only on one surface. The thickness when the auxiliary metal part is provided only on one side is twice the thickness when the auxiliary metal part is provided on both sides. When the thickness X4 of the auxiliary metal portion (see FIG. 8) is smaller than the thickness X2 of the active material layer (electrode layer), the deformation of the end portion of the strip electrode becomes remarkably large, so that X4> X2. preferable. In addition, a fixed pressure is applied to the thickness direction at the time of manufacture of a laminated body.

  As described above, the electrochemical device manufacturing method according to the embodiment includes the following steps (1) to (6).

  Step (1): In this step, a positive electrode strip electrode A on which a positive electrode side active material layer AE1 and a positive electrode side auxiliary metal portion T1 are formed is prepared. That is, in the formation of the active material layer AE1, as described above, the active material is emitted from the nozzle onto the main metal foil A1 and applied, and the auxiliary metal portion T1 welds a thin metal strip to the main metal foil A1. And fix.

  Step (2): In this step, a negative electrode strip electrode K on which the negative electrode side active material layer KE1 and the negative electrode side auxiliary metal portion T2 are formed is prepared. That is, in the formation of the active material layer KE1, as described above, the active material is emitted from the nozzle onto the main metal foil K2 and applied, and the auxiliary metal portion T2 has a thin metal strip on the main metal foil K2. Fix by welding.

  Step (3): In this step, a positive electrode side thermoplastic resin is disposed between the positive electrode side auxiliary metal portion T1 and the positive electrode side active material layer AE1. Similarly, a negative electrode side thermoplastic resin is arrange | positioned between the negative electrode side auxiliary metal part T2 and the negative electrode side active material layer KE1. Steps (1) and (2) are performed in the same manner for the structures T1 (b) and T2 (b) on the back surface side. Further, the thermoplastic resin on the back side is also formed between the positive electrode side auxiliary metal part T1 (b) and the positive electrode side active material layer AE2 and between the negative electrode side auxiliary metal part T2 (b) and the negative electrode side active material layer KE2. Arranged between.

  Step (4): The strip electrode formed as described above and the separator are overlapped and laminated as shown in FIG. 4, and this laminate is wound as shown in FIG.

  Step (5): After winding the strip electrode, heat treatment is performed to melt the thermoplastic resin. This overheating is caused by positive electrode side thermoplastic resin TC1 located on the front surface side contacting both the side surface of positive electrode side auxiliary metal portion T1 and the side surface of positive electrode side active material layer AE1, and positive electrode side thermoplastic resin located on the back surface side. TC1 (b) is performed until it contacts both the side surface of the positive electrode side auxiliary metal part T1 (b) and the side surface of the positive electrode side active material layer AE2. By this step, the resin melts and deforms as shown in FIG. In the figure, only the resin melting behavior on the front surface is shown, but the same phenomenon occurs on the back surface side. The heating temperature is specifically 180 ° C., but any heating temperature within the range of the resin melting temperature can be used.

  Of course, due to the heating at this time, the negative electrode side thermoplastic resin TC2 on the front surface side contacts both the side surface of the negative electrode side auxiliary metal portion T2 and the side surface of the negative electrode side active material layer KE1, and further, the negative electrode side thermoplastic resin on the back surface side. The resin TC2 (b) contacts both the side surface of the negative electrode side auxiliary metal portion T2 (b) and the side surface of the negative electrode side active material layer KE2. These heating steps are performed simultaneously, and as described above, the heating temperature is specifically 180 ° C., but within the range of the resin melting temperature, even if the temperature is higher than this, Even temperature can be employed.

  Step (6): In this step, all the thermoplastic resins are cooled and solidified to form reinforcing resin layers TC1, TC1 (b), TC2, and TC2 (b). Although FIG. 6C shows only the behavior of the surface on the positive electrode side, the resin is flattened and solidified as shown in FIG. 6C by this step. The cooling temperature may be room temperature. The behavior of the positive and negative front and back resins is the same as in the case of FIG. This cooling / solidification step can be performed in the drying step of the electrochemical device body after heating.

  In addition, by providing the above-mentioned resin heating step (resin melting step), one end surface in the width direction of the strip-shaped electrode in the wound laminated body is held so as to face vertically upward, and the end surface portion facing upward If only the upper side is heated, the molten resin flows only in the direction of one active material layer located below. Furthermore, when the intermediate body of this electrochemical device body is turned upside down and the upper end surface portion on the opposite side is heated in the same manner, the molten resin is positioned below as in the case shown in FIG. It flows only in one active material layer direction.

  Therefore, when both the upper and lower sides of the wound laminate are heated, on the upper side, the resin flows in the direction of the active material layer, and on the lower side, flows in the direction of the auxiliary metal part. Similarly, if the upper side and the lower side of the laminate are both heated, similarly, the resin flows in the direction of the active material layer on the upper side and flows in the direction of the auxiliary metal part on the lower side. By doing in this way, resin can be made to contact both an active material layer and an auxiliary metal part. In addition, as a method for heating only the vicinity of the end face, there are hot air drying, infrared irradiation heating, and heating with a heating wire. Of course, the laminate may be heated in whole or in part while rotating or swinging the laminate, and the active material layer and auxiliary metal may be heated by heating the resin before winding. It is also possible to keep both parts in contact.

  According to the above-described method, the thermoplastic resin is heated to form the above-described reinforcing resin layer, so that it can be easily brought into contact with the active material layer of each electrode and the side surface of the auxiliary metal portion. In addition, it is easy to manufacture an electrochemical device in which variation in characteristics is suppressed.

  After the formation of the respective strip electrodes, strip electrodes A and K are stacked together with separators S1 and S2 as shown in FIG. 4 and wound around the Z axis to manufacture the electrochemical device body 10. Note that the wound strip electrode and the terminal end of the separator are fixed with tape or an adhesive. Thereafter, the electrochemical device body is assembled according to the steps shown in FIG. That is, the electrochemical device body 10 is enclosed in the enclosure together with the electrolytic solution, the upper and lower electrode plates are laser welded, pressure is applied to the outer surface of the cylinder from the outside to form the tightening portion SB, and the heat is applied to the outside of the enclosure. Fit the shrink tube and heat it. Thereby, said electrochemical device is completed.

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. 8 is a diagram for explaining the dimensions of the constituent elements of the strip electrode.

  Explaining the dimensions in the Z-axis direction, the dimension Z1 is the width of the main metal foils A1, K2, the dimension Z2 is the width of the active material layers AE1, AE2, KE1, KE2, and 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 layer in the Z direction, the dimension Z5 indicates the width of the auxiliary metal portions T1 and T2, 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, K2, the dimension X2 is the thickness of the active material layers AE1, AE2, KE1, KE2, and the dimension X3 is the thickness of the separators S1, S2. The dimension X4 is the thickness of the auxiliary metal portions T1 and T2. The reinforcing resin layers TC1, TC1 (b), TC2, and TC2 (b) have a thickness of X5.

The preferred range of each dimension is as follows.
10 ≦ Z1 ≦ 1000mm
5mm ≦ Z2 ≦ 995mm
2mm ≦ Z3 ≦ 50mm
1mm ≦ Z4 ≦ 10mm
1mm ≦ Z5 ≦ 49mm
7mm ≦ Z6 ≦ 997mm

10 μm ≦ X1 ≦ 200 μm
10 μm ≦ X2 ≦ 500 μm
10 μm ≦ X3 ≦ 50 μm
10 μm ≦ X4 ≦ 500 μm
10 μm ≦ X5 ≦ 200 μm <X2 <X4

  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 device function, it is preferable that the region is small from the viewpoint of miniaturization. After the strip electrode is wound, both ends in the width direction are cut perpendicularly to the Z axis to cut the cut surface. 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.

  Z5 defines the width of the auxiliary metal portions T1 and T2, and is set to the width Z3-1mm of the exposed region.

  The range of X1 is a realistic thickness range of the main metal foil that is a current collector. A thicker one is preferable from the viewpoint of low resistance and high strength, but the degree of integration per unit volume Becomes so low that a large amount of charge 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. Since the thickness X5 of the resin layer is smaller than the thickness X2 of the active material layer, when the electrolyte solution is injected in the Z-axis direction, the shoulder portion of the active material layer is exposed and the electrolyte solution can easily penetrate into the active material layer. Become.

  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.

  The range of X4 is less than or equal to the total thickness of the layers located between adjacent main metal foils and may be about 1000 μm, but the physical constraint condition that the strip electrode can be wound is more than the total of the layers. From this viewpoint, X4 is preferably 500 μm or less, and the thickness is preferably the same as that of the main metal foil from the viewpoint of reducing internal stress. Therefore, X4 is preferably 10 μm or more and 500 μm or less, which is the lower limit value of the thickness X1 of the main metal foil.

  According to the electrochemical device described above, the auxiliary metal portions T1 and T2 narrow the movable range in the radial direction (X-axis direction in FIG. 8) in the exposed regions of the main metal foils A1 and K2, and thus the main metal foils A1 and K2 The impedance change due to the positional deviation in the X-axis direction can be suppressed. Since the auxiliary metal portions T1 and T2 have the thickness X4, the auxiliary metal portions T1. The contact area between the side surface (XY plane) of T2 and the above-described electrode plate can be increased, and the contact resistance can be decreased. Thus, when the contact resistance is 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. The thickness X4 is preferably as large as possible from the above viewpoint.

  Further, the thickness X4 of the auxiliary metal part alone when the auxiliary metal parts T1 and T2 are formed on both surfaces is doubled or the thickness X4 of the auxiliary metal part alone when the auxiliary metal parts T1 and T2 are formed on one side. Is not more than the distance L (= 4 × X2 + 2 × X3 + X1) of the gap between the opposing main metal foils A1 (or K2) in the exposed region (region of dimension Z3). In this case, the auxiliary metal portions T1 and T2 do not push the distance L between the main metal foils A1 and K2 at the end in the width direction (Z-axis direction), and the increase in the radial dimension is suppressed. can do. Of course, twice the single thickness X4 of the auxiliary metal portions T1 and T2 (during double-sided formation) or the thickness X4 (during single-sided formation) may coincide with the distance L of the gap. It is possible to reliably suppress the radial movement in the exposed areas of the metal foils A1 and K2, and to electrically connect the main metal foils A1 (or K2) to improve the strength and electrical stability. it can.

  When the thickness X4 is twice (during double-sided formation) or the thickness X4 (during single-sided formation) is smaller than the distance L (= 4 × X2 + 2 × X3 + X1), a slight gap is formed between the auxiliary metal portions T1, T2 and the main electrode A1, Since there is a slight gap between K2 and K2, a penetration gap for the electrolyte introduced along the Z-axis direction is ensured, the electrolyte enters the interior sufficiently, variation in impedance is suppressed, and impedance characteristics are reduced. Will be improved.

  The thickness X5 of the reinforcing resin layers TC1 and TC2 in the Z-axis direction is preferably 10 μm to 200 μm from the viewpoint of no peen holes and ensuring flexibility, and electrolysis introduced from the outside along the Z-axis direction. In order to introduce the liquid into the active material layer, it is preferable that the reinforcing resin layers TC1 and TC2 do not contact the separators S1 and S2 and have a slight gap (X2-X5> 0).

A ... anode electrode, A1, K2 ... main metal foil, AE1, AE2, KE1, KE2 ... active material layer, K ... cathode electrode, T1, T2 ... auxiliary metal part, TC1, TC2: Reinforcement resin layer.

Claims (5)

An enclosure,
An electrochemical device body enclosed within the enclosure, the electrochemical device body having a wound positive electrode strip electrode and a negative electrode strip electrode wound so as to face the positive electrode strip electrode;
A separator interposed between the positive electrode strip electrode and the negative electrode strip electrode;
With
The positive electrode strip electrode is
A wound belt-like positive-side main metal foil;
A positive electrode side active material layer formed around the winding axis of the positive electrode main metal foil;
A positive side auxiliary metal part provided on the positive side main metal foil along the winding axis at one end side along the winding axis of the positive side main metal foil;
It is made of a positive electrode side thermoplastic resin provided between the positive electrode side auxiliary metal part and the positive electrode side active material layer, is thinner than the positive electrode side auxiliary metal part and does not contact the separator, and the positive electrode side auxiliary metal part A positive-side reinforcing resin layer that is in contact with both the side surface of the metal part and the side surface of the positive-electrode side active material layer;
Have
The negative electrode strip electrode is
A wound strip-shaped negative-side main metal foil;
A negative electrode side active material layer formed along the winding axis of the negative electrode side main metal foil,
A negative side auxiliary metal part provided on the negative side main metal foil along the winding axis on the other end side along the winding axis of the negative side main metal foil;
It consists of a negative electrode side thermoplastic resin provided between the negative electrode side auxiliary metal part and the negative electrode side active material layer, is thinner than the negative electrode side auxiliary metal part and does not contact the separator, and the negative electrode side auxiliary material A negative electrode side reinforcing resin layer in contact with both the side surface of the metal part and the side surface of the negative electrode side active material layer;
An electrochemical device comprising:   2. The electrochemical according to claim 1, wherein one end in the winding axis direction of the positive electrode strip electrode and the negative electrode strip electrode is directly welded to an electrode plate constituting a lid of the enclosure. device. The enclosure is
A metal cylinder,
An insulating ring interposed between the electrode plate and the cylinder;
A heat-shrinkable tube covering the peripheral portion of the electrode plate and the outer surface of the cylindrical body;
The electrochemical device according to claim 1, further comprising: The enclosure includes a metal cylinder sealed by the electrode plate,
A part of the cylindrical body is provided with a narrowing portion that is recessed from the outer periphery toward the center direction to fix the cylindrical body in contact with the outer surface of the electrochemical device body. The electrochemical device according to claim 1 or 2. In the manufacturing method of the electrochemical device of any one of Claims 1 thru | or 4,
Preparing the positive electrode strip electrode in which the positive electrode side active material layer and the positive electrode side auxiliary metal part are respectively formed;
Preparing the negative electrode strip electrode in which the negative electrode side active material layer and the negative electrode side auxiliary metal part are respectively formed;
A step of disposing a positive side thermoplastic resin between the positive side auxiliary metal part and the positive side active material layer;
Disposing a negative electrode side thermoplastic resin between the negative electrode side auxiliary metal part and the negative electrode side active material layer;
The positive side thermoplastic resin is in contact with both the side surface of the positive side auxiliary metal portion and the side surface of the positive side active material layer, and the negative side thermoplastic resin is in contact with the side surface of the negative side auxiliary metal portion and the negative electrode. Heating the positive side thermoplastic resin and the negative side thermoplastic resin so as to contact both side surfaces of the side active material layer;
Cooling and solidifying the positive electrode side thermoplastic resin and the negative electrode side thermoplastic resin to form the positive electrode side reinforcing resin layer and the negative electrode side reinforcing resin layer;
The manufacturing method of the electrochemical device characterized by the above-mentioned.

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