JP2005149980A - Current collector with terminal, electrochemical element using this - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a current collector with terminal in which jointing strength between an external terminal and a current collector is strong, and which has a low resistance owing to low resistance of the external terminal itself and low resistance between the current collector and the external terminal, and also to provide an electrochemical element using this current collector with terminal. <P>SOLUTION: The current collector with terminal comprises a current collector main body being an electrode to be filled with an active material, and a terminal jointed to the current collector main body. The terminal is made of an uneven metal body having irregularity on the surface and the jointing parts of the protruded parts surrounding the recess parts of the uneven metal body are all in solid solution state. The electrochemical element uses the above current collector with terminal. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a current collector with a terminal and an electrochemical element using the current collector, for example, an alkaline secondary battery, a lithium ion secondary battery, or an electric double layer capacitor.

  2. Description of the Related Art Conventionally, alkaline secondary batteries are highly reliable and can be reduced in size and weight, and thus are widely used as power sources for various devices ranging from portable devices to industrial large facilities. In this alkaline secondary battery, a nickel electrode is generally used as a positive electrode, and this nickel electrode is obtained by carrying a positive electrode active material for causing a battery reaction on a current collector that shares a current collecting function. Become. As the current collector, a sintered nickel plate or a punched nickel plate obtained by sintering nickel powder has been widely used. Since the capacity of the battery is determined by the amount of the active material filled in the gap of the current collector, and the amount of the active material is determined by the porosity of the current collector, it is preferable that the porosity of the current collector is as large as possible.

  However, since the conventional sintered nickel plate and punched nickel plate have a low porosity of 75 to 80% and it is difficult to fill the active material with a high density, recently, the porosity is high, As a current collector that can be filled with a high density, the applicant of the present application is “a nonwoven fabric hydrophilized by sulfonation treatment, fluorine gas treatment or vinyl monomer grafting treatment, and a nickel plating film formed on the surface of the nonwoven fabric. Proposed a current collector for an alkaline secondary battery provided with (Patent Document 1). This current collector is formed in a band shape, crushes the location where the external terminal for conducting electricity to the battery encapsulating plate or the battery can bottom is crushed, filled with paste containing the active material, dried and rolled, and then further crushed. A nickel piece as an external terminal is spot-welded to the spot, thereby forming an electrode with a terminal (a positive electrode with a terminal or a negative electrode with a terminal). An electrode group in which a separator is interposed between the positive electrode with terminal and the negative electrode with terminal is formed, and the electrode group is accommodated in a battery case to form a battery. Although this current collector itself was certainly high in current collection performance, when a terminal-attached electrode was manufactured by spot welding a nickel piece normally used as an external terminal, the bonding strength between the current collector and the external terminal was high. Problems of external terminals coming off when forming the electrode group due to weakness, and problems such as high internal impedance when the battery is manufactured due to high resistance between the external terminals and the current collector and inferior high-rate discharge characteristics was there.

  In order to solve such a problem, an alkaline secondary in which one or two or more positive or negative terminals are welded to the current collector via a metal tape on a current collector made of a non-woven fabric plated with nickel A battery electrode "has been proposed (Patent Document 2). As the metal tape, a net woven of nickel wire or a non-woven fabric made of nickel wire is disclosed. This electrode is welded to a net woven with nickel wire or a non-woven fabric made of nickel wire, so the welding strength is strong, but the resistance of the non-woven fabric itself made of a net woven with nickel wire or nickel wire is high. There was a problem of high internal impedance.

  Although the above is about an alkaline secondary battery, the same problem also exists in other electrochemical elements (for example, a lithium ion secondary battery or an electric double layer capacitor).

JP-A-2001-313038 (Claims, paragraph number 0032, Examples 5-6, etc.) JP 2002-319410 A (Claim 1, Claim 5, etc.)

  The present invention has been made in order to solve the above-described problems, and the bonding strength between the external terminal and the current collector is strong, and the resistance between the external terminal itself and the current collector and the external terminal is high. It aims at providing the current collection material with a terminal with low resistance by being low. It is another object of the present invention to provide an electrochemical device using the current collector with terminal.

  The invention according to claim 1 of the present invention is such that, in the current collector with a terminal including a current collector main body filled with an active material and serving as an electrode, and a terminal joined to the current collector main body, the terminal has an uneven surface. It is a current collector with terminals characterized in that the joint portion of the convex portions surrounding the concave portion of the concave-convex metal body is in a solid solution state. As described above, the current collector with terminal of the present invention is composed of an uneven metal body having irregularities on the surface, and due to the anchor effect, the bonding strength between the current collector main body and the terminal is high, so that the terminal may come off when the electrode group is formed. Moreover, the resistance between the current collector main body and the terminal is low. In addition, a conventional non-woven fabric made of a nickel wire woven net or nickel wire has a high resistance, such as a low degree of contact between nickel wires or a non-contact nickel wire. On the other hand, since the concavo-convex metal body that is the terminal of the current collector with a terminal of the present invention is in a solid solution state, the joints between the bulges surrounding the concave part are low in resistance of the concavo-convex metal body (terminal) itself, It is a current collector with terminals with low resistance.

  The invention according to claim 2 of the present invention is as follows: “The current collector main body is formed by plating the nonwoven fabric and not thermally removing the nonwoven fabric. Current collector ”. Thus, when the current collector main body is made of a plated nonwoven fabric in which the nonwoven fabric is not thermally decomposed and removed, when the terminals are connected, not only the joining of the terminal component metal and the plated metal but also the resin constituting the plated nonwoven fabric melts. The anchor effect by taking out can also be anticipated, and it can be excellent joint strength.

  The invention according to claim 3 of the present invention is "the current collector with terminal according to claim 1 or 2, wherein the concavo-convex metal body is made of a punching metal or an expanded metal". Such punching metal or expanded metal has a large number of openings through which the recesses penetrate, and therefore has high bonding strength due to the anchor effect.

  The invention according to claim 4 of the present invention is as follows: “The current collector main body has a rectangular shape, and terminals are joined to all sides of the current collector main body. It is a current collector with terminals according to the above. The current collector with terminal forms an electrode group, and then a current collector plate is joined to the terminal, thereby enabling high-rate discharge.

  The invention according to claim 5 of the present invention is "an electrochemical element using the current collector with terminal according to any one of claims 1 to 4". The current collector with terminal of the present invention is an electrochemical element that has a strong bonding strength between the terminal and the current collector body and can be manufactured without causing defects due to the terminal being detached during the electrode group configuration. In addition, since the resistance of the terminal itself and the resistance between the terminal and the current collector main body are low, the electricity can be smoothly taken in and out, and the charge / discharge efficiency is high. Therefore, it can be an electrochemical device having a high utilization rate and excellent high rate charge / discharge characteristics.

  The invention according to claim 6 of the present invention is an electrochemical device according to claim 5, which is an electrochemical element selected from an alkaline secondary battery, a lithium ion secondary battery, and an electric double layer capacitor. Element ". As described above, the alkaline secondary battery, the lithium ion secondary battery, and the electric double layer capacitor use the current collector with a terminal of the present invention, and thus can be manufactured without causing a defect, and have high charge / discharge efficiency, and can be used. The rate is high and the high rate charge / discharge characteristics are excellent. In particular, the alkaline secondary battery using the terminal current collector according to the invention of claim 4 can be an alkaline secondary battery capable of high-rate discharge.

  The current collector with terminal of the present invention has a high bonding strength between the external terminal and the current collector, and has a low resistance due to the low resistance between the external terminal itself and the current collector and the external terminal.

  Since the electrochemical device of the present invention uses the current collector with a terminal of the present invention, it can be produced without disconnecting the terminal, and has high charge / discharge efficiency, high utilization, and excellent high rate charge / discharge characteristics. Can be things.

  The current collector main body of the present invention carries an active material and functions to collect the charge of the active material, and a known material can be used. For example, a sintered nickel plate, a punched nickel plate, or a porous body such as a foam or a nonwoven fabric plated (a foam or a nonwoven fabric may be removed by thermal decomposition) or the like can be used.

  Among these, the non-woven fabric that is not thermally decomposed and removed by simply plating the nonwoven fabric can be suitably used as the current collector main body. This is because when the terminals are connected, the bonding strength between the current collector and the terminal is strong due to the anchor effect caused by the dissolution of the resin constituting the plated non-woven fabric as well as the bonding between the terminal constituent metal and the plated metal. . Nonwoven fabrics have a large specific surface area compared to conventional foamed nickel and metal foil, and a large contact area with the active material and activated carbon. Can be manufactured. Furthermore, since the nonwoven fabric is excellent in flexibility, there is no cracking at the time of electrode group production (for example, at the time of winding), an effect that an edge caused by the crack does not occur, and an electrode group (positive electrode, negative electrode and Adhesion of the separator) is improved, the internal impedance is lowered, the utilization factor is high, and an electrochemical element excellent in high rate charge / discharge characteristics can be produced. Among the current collector main bodies, those obtained by plating hydrophilic nonwoven fabrics can be particularly preferably used. This is because the adhesion between the plating film and the non-woven fabric is excellent, and it does not fall off even when the electrochemical device is assembled or repeated charging and discharging.

  The current collector main body of the present invention can be produced by a conventional method. For example, a current collector main body obtained by plating a suitable non-woven fabric subjected to hydrophilic treatment can be manufactured as follows. First, a fiber web is formed by a dry method such as a card method, an air lay method, a melt blow method, a spun bond method, or a wet method. In addition, the fiber which comprises a fiber web changes with the uses (electrochemical element) of the collector material with a terminal. For example, when used for alkaline secondary batteries, polyolefin fibers and / or polyamide fibers can be used, and when used for lithium ion secondary batteries, polyolefin fibers, aromatic polyamide fibers, Polyimide fiber, wholly aromatic polyester fiber, polyamideimide fiber, aromatic polyetheramide fiber, and / or polybenzimidazole fiber can be used. When used for electric double layer capacitors, polyamide fiber, polyolefin Base fibers, polyester fibers, and / or cellulosic fibers can be used.

  Subsequently, the nonwoven fabric can be produced by combining the fiber webs by entanglement treatment (water entanglement treatment, needle punching treatment), fusing treatment or adhesion treatment alone or in combination. In particular, it is preferable to fuse fibers by a fusion treatment because the strength of the nonwoven fabric is excellent. In addition, when fusing a fiber by a fusing process, a low melting point fiber (particularly, in addition to a low melting point resin, a low melting point resin having a resin having a melting point lower than that of other fibers) It is preferable that a composite fiber having a high melting point resin having a high melting point is included in the fiber web.

  Next, the nonwoven fabric is hydrophilized by a conventional method. Examples of the hydrophilization treatment include sulfonation treatment, fluorine gas treatment, vinyl monomer graft treatment, or corona discharge treatment.

  Then, the current collector main body can be manufactured by plating the nonwoven fabric hydrophilized by a conventional method. For example, a non-woven fabric that has been hydrophilized by electroless plating can be plated. After forming an electroless plating film on a non-woven fabric that has been hydrophilized by electroless plating, an electroplating film is further formed by electroplating. It is preferable to do this. In addition, it is preferable that the plating amount to the nonwoven fabric which performed the hydrophilic treatment is 30 to 70% of the mass of the current collector main body. If it is less than 30%, the resistance tends to be high, and if it exceeds 70%, the fiber is thickened by the plated metal, and the pore diameter of the current collector main body is reduced, so that the active material filling property tends to be poor. Because. The type of plating metal can be appropriately selected as long as the metal does not deteriorate due to the reaction of the electrolytic solution or the electrochemical element. For example, nickel is used for alkaline secondary batteries, and copper, positive electrodes, and negative electrodes are used for negative electrodes in lithium ion secondary batteries. For use, nickel or titanium can be used, and for electric double layer capacitors, nickel or titanium can be used.

  The current collector with a terminal of the present invention has a terminal joined to the current collector main body as described above, and this terminal is composed of an uneven metal body having irregularities on the surface, and the bonding strength between the current collector main body and the terminal by the anchor effect Therefore, the terminal does not come off when the electrode group is formed, and the resistance between the current collector main body and the terminal is low. Moreover, since all the junction parts of the convex parts surrounding the recessed part of an uneven | corrugated metal body are in a solid solution state, resistance of an uneven | corrugated metal body (terminal) itself is low, and it is a current collector with a terminal with low resistance. In other words, the conventionally proposed non-woven fabric made of nickel wire or nickel wire has a high resistance, such as a low degree of contact at the intersection of nickel wires or a non-contact nickel wire. On the other hand, in the concavo-convex metal body that is a terminal of the current collector with a terminal of the present invention, since the joints between the bulges surrounding the dents are in a solid solution state, the concavo-convex metal body (terminal) itself This is a current collector with a terminal having low resistance.

  In addition, the uneven metal body which comprises the terminal of this invention should just have an unevenness | corrugation on the surface, and it is an uneven | corrugated metal body which has an unevenness | corrugation even when a recessed part does not exist completely, ie, it is a through-hole. Further, in the present invention, “the joints between the convex portions surrounding the concave portions are in a solid solution state” means a state where they are simply in contact with each other like a conventional mesh made of nickel wire or a non-woven fabric made of nickel wire. Unlike the case, it means a state in which the joints between the protrusions are completely integrated like a solid solution, and the joints between the protrusions are inseparable by an external force such as an unintended hand.

  In addition, the concavo-convex metal body is not particularly limited as long as it is made of a metal suitable for the intended use (electrochemical element) of the current collector with terminal. For example, in an alkaline secondary battery, nickel, lithium ion In the secondary battery, copper can be used for the negative electrode, nickel or titanium can be used for the positive electrode and the negative electrode, and nickel or titanium can be used for the electric double layer capacitor.

  As the concavo-convex metal body (terminal) of the present invention, for example, expanded metal or punching metal can be used. This expanded metal or punching metal is suitable because it has a large number of openings through which the recesses penetrate, and therefore has high bonding strength due to the anchor effect.

  Here, a terminal made of expanded metal will be described with reference to FIG. The expanded metal 1 has a large number of concave and convex units each including a concave portion 2 that penetrates and a convex portion 3 that surrounds the concave portion 2, and the joint portions (3a, 3b, 3c, and 3d in FIG. 1) are in a solid solution state. is there. That is, the expanded metal is formed by forming a recess 2 derived from the slit by applying an external force in a direction perpendicular to the slit direction after slitting the metal sheet in a certain direction. Since is a part of the original metal sheet, it is in a completely integrated state (solid solution state).

  In the expanded metal, the shorter the center distance in the short direction (SW in FIG. 1) and the center distance in the long direction (LW in FIG. 1), the shorter the mesh (concave portion 2 and convex portion 3). It is preferable because there are many, the bonding strength between the current collector main body and the terminal is strong, and the resistance is low. For example, when a rectangular terminal having a junction width of about 3 mm and a length of about 5 mm is used as the terminal, the center distance in the short direction is 3 mm or less and the center distance in the long direction is 5 mm or less. Preferably there is. More preferably, the center distance in the short direction is 1 mm or less, the distance in the center direction in the long direction is 2 mm or less, more preferably the distance in the center direction in the short direction is 0.5 mm or less, and the distance in the center direction in the long direction is 1 mm. It is as follows. The lower limit is not particularly limited as long as the anchor effect can be effectively exhibited. However, the distance between the short-direction centers is preferably 0.25 mm or more, and the distance between the long-direction centers is 0.5 mm or more. Is preferred.

  Further, the thickness of the expanded metal (T in FIG. 1) varies depending on the use application (electrochemical element) of the current collector with terminal, and is not particularly limited. For example, when used in a cylindrical battery, it is necessary to wind the current collector with a terminal and the separator in a cylindrical shape when forming the electrode group, and the flexibility that can be wound is necessary. The thickness of the metal is preferably 0.5 mm or less. On the other hand, if it is too thin, the strength of the expanded metal becomes weak and the electrical resistance tends to increase. Considering these balances, the expanded metal thickness is more preferably 0.05 to 0.2 mm.

  Further, the shape of the opening of the expanded metal (that is, the shape of the recess 2) is not particularly limited, and examples thereof include a diamond shape, a turtle shell shape, and a ginkgo shape.

  When joining such a terminal made of expanded metal to the current collector main body, the long direction of the expanded metal is the direction of movement of electricity (for example, in the case of an alkaline secondary battery, the lid direction or the battery so that the resistance is low). It is preferable to join so as to coincide with the direction of the bottom of the can.

  Another punching metal, which is a terminal, will be described with reference to FIG. The punching metal 10 includes a large number of concave and convex units each including a concave portion 20 that penetrates and a convex portion 30 that surrounds the concave portion 20, and joints between the convex portions (30 a, 30 b, 30 c, 30 d, 30 e, and 30 f in FIG. 1) It is in a solid solution state. That is, the punching metal is formed by punching a metal sheet to form the recess 20, and the joint between the protrusions is a part of the original metal sheet, and thus is in a completely integrated state (solid solution state).

  In addition, as for both the distance between holes in punching metal (P in FIG. 2) and the diameter of the hole (D in FIG. 2), the shorter one has more concave portions 20 and convex portions 30 in the joint portion, and the current collector This is suitable because the bonding strength between the main body and the terminal is strong and the resistance is low. For example, when a rectangular terminal having a bonding width of about 3 mm and a length of about 5 mm is used as the terminal, the hole diameter (D) is less than 3 mm, and the inter-hole distance (P) is 3 mm or more. Preferably there is. More preferably, the hole diameter (D) is less than 2 mm, the inter-hole distance (P) is 2 mm or more, more preferably the hole diameter (D) is less than 1 mm, and the inter-hole distance (P) is 1 mm or more. is there. In addition, as long as the anchor effect can be exhibited effectively, the lower limit of the hole diameter (D) is not particularly limited, but is preferably 0.5 mm or more. On the other hand, the upper limit of the inter-hole distance (P) is not particularly limited as long as the anchor effect can be exhibited effectively, but it is preferably 5 mm or less.

  The thickness of the punching metal varies depending on the usage of the current collector with terminal and is not particularly limited. For example, when used in a cylindrical battery, it is necessary to wind the current collector with a terminal and the separator in a cylindrical shape when forming the electrode group, and the flexibility that can be wound is necessary. The thickness of the metal is preferably 0.5 mm or less. On the other hand, if the thickness is too thin, the strength of the punching metal is weakened and the electrical resistance tends to be high. Therefore, the thickness is preferably 0.01 mm or more. Considering these balances, the thickness of the punching metal is more preferably 0.05 to 0.2 mm.

  Although the shape of the recessed part 20 of a punching metal is not specifically limited, For example, a round hole, a long hole, a square hole, a turtle shell hole, a decoration hole, etc. can be mentioned. When the shape of the recess 20 is other than a round hole, the diameter (D) of the hole means a diameter of a circle that can circumscribe the outer periphery of the hole, and the distance (P) between the holes is a hole in an adjacent hole. The distance between the centers of the circles that can circumscribe the outer circumference of the circle.

  The shape of such a terminal is not particularly limited, but is generally rectangular.

  The terminal can be joined to the current collector main body by, for example, a spot welder, a seam welder, an ultrasonic welder, or a heat sealer. In addition, in the case where the current collector main body is a non-woven fabric plated and the nonwoven fabric is not thermally decomposed and removed, the condition that the resin constituting the non-woven fabric melts so that the bonding strength between the terminal and the current collector main body is increased. It is preferred to join below.

  In addition, although the terminal should just be joined to a part of current collector main body, if the current collector main body has a rectangular shape and the terminal is joined to all sides of the current collector main body, this current collector with terminal is connected. After forming an electrode group by using, a current collector plate is joined to a terminal, whereby an electrochemical element capable of high-rate discharge can be manufactured.

  Since the electrochemical device of the present invention uses the current collector with a terminal of the present invention as described above, it can be manufactured without detaching the terminal when forming an electrode group, and the internal impedance is low. Also, it has excellent high rate discharge characteristics. Although it does not specifically limit as an electrochemical element of this invention, For example, an alkaline secondary battery, a lithium ion secondary battery, or an electric double layer capacitor can be mentioned.

  The electrochemical device of the present invention can be exactly the same as the conventional electrochemical device except that the current collector with terminal of the present invention is used. For example, in a nickel metal hydride battery, nickel hydroxide is supported on the current collector with a terminal of the present invention as a positive electrode active material to constitute a positive electrode, and a hydrogen storage alloy is supported on the current collector with a terminal of the present invention as a negative electrode active material. Configure the negative electrode. In addition, an electrode group in which a separator is interposed between the positive electrode and the negative electrode is sealed in a battery can together with an alkaline electrolyte. The positive electrode is joined to the lid of the battery can through the terminal, and the negative electrode is in contact with the inner side surface of the battery can or joined to the bottom of the battery can by the terminal. In the case of an alkaline secondary battery for high rate, the current collector material body has a rectangular shape, and the electrode group using the current collector material with terminals in which the terminals are joined to all sides of the current collector material body is a current collector plate. It has the structure joined to the lid | cover of the battery can through this.

A lithium ion secondary battery, which is another electrochemical element, is prepared by using, for example, a paste of a lithium-containing metal compound such as a lithium-containing metal oxide, sulfide, or chloride as a positive electrode active material as the current collector with a terminal of the present invention. A positive electrode is formed by supporting, lithium metal or lithium alloy as a negative electrode active material, and carbon materials containing carbon or graphite capable of occluding and releasing lithium (for example, carbon materials such as coke, natural graphite and artificial graphite), composite tin An oxide is supported on the current collector with a terminal of the present invention to constitute a negative electrode. In addition, an electrode group in which a separator is interposed between the positive electrode and the negative electrode is enclosed in a battery can together with an electrolytic solution (for example, a nonaqueous electrolytic solution in which LiPF ₆ is dissolved in a mixed solvent of ethylene carbonate and diethyl carbonate). It has a structure. The positive electrode is joined to the lid of the battery can through the terminal, and the negative electrode is in contact with the inner side surface of the battery can or joined to the bottom of the battery can by the terminal.

  As the current collector used in the lithium ion secondary battery, since a foil having a thickness of about 10 to 20 μm is usually used, the current collector with a terminal of the present invention has a low basis weight and is preferably thin. However, when the metal sheet is used as the terminal because the metal weight is low due to the low basis weight, it tends to be difficult to join the terminal. If a non-current collector body is used, a strong joint strength can be obtained regardless of the amount of metal due to the anchor effect of the resin constituting the plated non-woven fabric melting out. Lithium ion secondary batteries can also be manufactured.

  Furthermore, the electric double layer capacitor which is another electrochemical element is, for example, a paste in which conductive carbon particles are added to a polarizable electrode material containing at least activated carbon, and alcohols, ketones, esters and amides are used as solvents. Is composed of a positive electrode and a negative electrode carried on the current collector with terminal of the present invention. In addition, an electrode group in which a separator is interposed between the positive electrode and the negative electrode is an electrolyte (electrolyte such as tetrafluoroborate salt, perchloride salt, hexafluorophosphate salt, carbonates, lactones, ethers, dimethyl sulfoxide, etc. And a structure enclosed in an outer can together. The positive electrode is bonded to the lid of the outer can through the terminal, and the negative electrode is bonded to the bottom of the can through the terminal.

  Examples of the present invention will be described below, but the present invention is not limited to the following examples.

(Example 1)
100% core-sheath type composite fiber (fineness: 6.6 dtex, fiber length: 5 mm) containing polypropylene as a core component and high-density polyethylene as a sheath component is used, and a fiber web is formed by wet papermaking. Was supplied to a hot-air dryer set at a temperature of 135 ° C., and the sheath component of the core-sheath composite fiber was fused to produce a nonwoven fabric having a basis weight of 100 g / m ² . Thereafter, the non-woven fabric was immersed in fuming sulfuric acid to carry out a sulfonation treatment to produce a non-woven fabric. Then, the sulfonated nonwoven fabric was subjected to nickel plating by an electroless plating method to produce a current collector main body (plating amount: 100 g / m ² , not pyrolyzed, rectangular with a length of 50 mm and a width of 100 mm). .

  On the other hand, a nickel expanded metal terminal (concave shape: rhombus, long mesh) having a short center distance (SW) of 0.5 mm, a long center distance (LW) of 1 mm, and a thickness of 0.1 mm. A rectangle having a direction of 20 mm and a short direction of 3 mm) was prepared.

  Next, the expanded metal is arranged at the center of the long side of the rectangular current collector so that the expanded metal overlaps by 5 mm (the long direction is arranged so as to be orthogonal to the long side), and then the current collector and the expanded metal are overlapped. The four corners and the center (five places in total) were welded with a spot welder (manufactured by Power Supply Co., Ltd.) to produce a current collector with terminals. In addition, it was in the state which the nonwoven fabric constituent resin melted out by this welding.

  The current collector with terminal was filled with nickel hydroxide, dried and pressed to produce a positive electrode.

  On the other hand, foamed nickel was filled with a hydrogen storage alloy, dried and pressed (rectangular shape having a length of 50 mm and a width of 120 mm). Also, a nickel expanded metal terminal similar to the positive electrode was prepared. And after arrange | positioning so that an expanded metal may overlap 5 mm in the center part of the long side of the said filled rectangular foam nickel (it arrange | positions so that a long direction may be orthogonal to a long side), filled rectangular foam nickel and an expanded metal, The negative electrode was manufactured by welding the four corners and the center (total of five locations) of the overlapped portions with a spot welder (manufactured by Power Supply Co., Ltd.).

  Next, the positive electrode and the negative electrode are cut into predetermined sizes (positive electrode: 40 mm long, 80 mm wide, negative electrode: 40 mm long, 100 mm wide), and then a separator made of a polyolefin nonwoven fabric that has been subjected to hydrophilic treatment by sulfonation is used as the positive electrode. It wound in the state interposed between the negative electrodes, and manufactured the electrode group.

  Next, this electrode group was put in an AA size battery can, and the negative electrode terminal was welded to the bottom of the battery can. Then, 2.5 g of alkaline electrolyte was put into the battery can, and the positive electrode terminal was spot welded to the battery lid, and then the battery lid was covered with a caulking machine to produce a nickel metal hydride battery having a theoretical capacity of 1300 mAh.

(Example 2)
Nickel expanded metal terminal (recess shape: rhombus, long direction is 0.5 mm, center distance in the short direction (SW) is 0.5 mm, center distance in the long direction is (LW) 1 mm, thickness is 0.1 mm) 120 mm and a rectangle whose short direction is 3 mm) was prepared.

  Next, the expanded metal terminal was welded to all the long sides of the current collector main body manufactured in the same manner as in Example 1 with a seam welder to manufacture a current collector with a terminal. In addition, it was in the state which the nonwoven fabric constituent resin melted out by this welding. In addition, welding was performed with a width of 3 mm from the end of the current collector main body so that the long direction of the expanded metal terminal was parallel to the long side of the current collector.

  The current collector with terminal was filled with nickel hydroxide, dried and pressed to produce a positive electrode.

  On the other hand, a negative electrode was produced in exactly the same manner as in Example 1, and an electrode group was produced in exactly the same manner as in Example 1.

  Next, this electrode group was put in an AA size battery can, and the negative electrode terminal was welded to the bottom of the battery can. Then, 2.5 g of alkaline electrolyte is put into the battery can, and the positive electrode terminal is spot-welded to the battery lid via a nickel current collector plate, and then the lid is covered with a battery lid by a caulking machine, and nickel hydride having a theoretical capacity of 1300 mAh. A battery was manufactured.

(Comparative Example 1)
An attempt was made to produce a positive electrode in exactly the same manner as in Example 1 except that a nickel sheet was used as the positive electrode terminal, but the current collector main body and the nickel sheet could not be welded, and a battery could be produced. could not. This was because the nickel sheet was smooth and the anchor effect did not occur.

(Comparative Example 2)
A nickel metal hydride battery having a theoretical capacity of 1300 mAh was manufactured in exactly the same manner as in Example 1 except that a 100 mesh nickel net was used as the positive electrode terminal.

(Comparative Example 3)
A 100-mesh nickel mesh was prepared as a positive electrode terminal, and a nickel mesh was welded to all the long sides of the current collector main body produced in the same manner as in Example 1 with a seam welder to produce a current collector with terminals. . In addition, it was in the state which the nonwoven fabric constituent resin melted out by this welding. Moreover, it welded by the width | variety of 3 mm from the edge part of a collector material main body.

  Subsequently, a positive electrode, a negative electrode, and an electrode group were produced in exactly the same manner as in Example 2.

  Next, this electrode group was put in an AA size battery can, and the negative electrode terminal was welded to the bottom of the battery can. Then, 2.5 g of alkaline electrolyte was put into the battery can, and the positive electrode terminal (nickel net) was spot-welded to the nickel current collector plate. However, because the resistance of the nickel net was high, welding could not be performed.

(Measurement of internal impedance)
The batteries of Examples 1 and 2 and Comparative Example 2 were charged for 12 hours at 130 mA and then paused for 15 minutes, and the process of discharging to 1.0 V at 130 mA and then paused for 15 minutes was regarded as one cycle, and 5 cycles were completed. The internal impedance between the positive electrode and the negative electrode at the time was measured at a frequency of 1 kHz. The results are shown in Table 1.

(Measurement of 4C utilization rate)
When each of the batteries subjected to the above (measurement of internal impedance) was charged for 4 hours at 390 mA, paused for 15 minutes, discharged to 0.8 V at 5200 mA, and then paused for 15 minutes, and when 3 cycles were completed The average value of the discharge capacity at 4 was taken as the 4C discharge capacity. And based on this 4C discharge capacity, 4C utilization was computed by the following formula | equation. The results are shown in Table 1.
4C utilization rate (%) = (4C discharge capacity ÷ 1300) × 100

  As is clear from Table 1, the current collector with terminal of the present invention is a material in which the current collector main body and the terminal are firmly welded, and the battery using the current collector with terminal of the present invention has low internal impedance, high It had excellent rate discharge characteristics.

Expanded metal perspective view Top view of punching metal

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Expand metal 2 Concave part 3 Convex part 3a, 3b, 3c, 3d Joint part of convex part 10 Punching metal 20 Concave part 30 Convex part 30a, 30b, 30c, 30d, 30e, 30f Joint part of convex part

Claims (6)

A current collector with a terminal comprising a current collector main body filled with an active material to be an electrode and a terminal joined to the current collector main body, wherein the terminal is made of an uneven metal body having an uneven surface, and the uneven metal body The terminal-attached current collector is characterized in that the joints between the convex portions surrounding the concave portion are in a solid solution state. The current collector with a terminal according to claim 1, wherein the current collector main body is formed by plating the nonwoven fabric but not thermally removing the nonwoven fabric. The current collector with terminal according to claim 1 or 2, wherein the concavo-convex metal body is made of a punching metal or an expanded metal. The current collector with terminal according to any one of claims 1 to 3, wherein the current collector main body has a rectangular shape, and terminals are joined to all sides of the current collector main body. The electrochemical element using the current collector with a terminal in any one of Claims 1-4. 6. The electrochemical device according to claim 5, wherein the electrochemical device is selected from an alkaline secondary battery, a lithium ion secondary battery, and an electric double layer capacitor.

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