JP2018045788A - Method and device for coating pasty electrode mixture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device for coating a pasty electrode mixture to form a hydrogen storage alloy negative electrode capable of reducing charge reserve of a nickel hydrogen secondary battery.SOLUTION: A device 13 for coating a pasty electrode mixture includes: a paste tank 17 for storing a pasty electrode mixture P; a paste coating part 18 which is pulled up from the paste tank 17 and has a slit part 18a through which a current collector (metal foil 11) having the pasty electrode mixture P coated on the surface can pass; and an electrode heating and drying part 19 which is provided behind the paste coating part 18. The coating device 13 is equipped with a voltage applying part 21 for applying voltage to the pasty electrode mixture P coated on the current collector when the current collector passes through the slit part 18a.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a paste electrode mixture coating method and a paste electrode mixture coating apparatus, and more specifically, to applying a paste electrode mixture coating for producing a hydrogen storage alloy negative electrode of a nickel metal hydride secondary battery. The present invention relates to a construction method and a paste electrode mixture coating apparatus.

Conventionally, a method for producing a hydrogen storage alloy electrode capable of reducing the internal pressure of the battery while ensuring the thickness of the active material layer deposited on the metal plate and the power density of the battery has been proposed (Patent Document 1). In this production method, a metal plate is pulled up from a hydrogen storage alloy paste (a paste electrode mixture) prepared using a highly polymerized methylcellulose having a weight average molecular weight of 1.2 to 1.3 × 10 ⁶ g / mol as a thickener. It is applied (coated) to a metal plate by the method.

  A nickel metal hydride secondary battery using a hydrogen storage alloy negative electrode produced by this manufacturing method has a suitable thickness and surface smoothness, and further avoids a decrease in energy density due to an increase in charge reserve, and further reduces the internal pressure of the battery. Can be reduced.

  As shown in FIG. 4, in the prior art, the amount of hydrogen storage alloy paste deposited on the metal plate, that is, the amount of paste applied increases as the amount of methylcellulose used increases, and the charge reserve (charge capacity of the hydrogen storage alloy negative electrode − It was found that the decrease in the charge capacity of the nickel hydroxide positive electrode) was large. The reason is considered as follows. After the hydrogen storage alloy electrode is incorporated in the battery, oxygen generated at the positive electrode during overcharge decomposes methylcellulose of the hydrogen storage alloy negative electrode to generate electrons, which are charged into the negative electrode and gradually become hydrogen storage alloy negative electrode. The extra chargeable amount (charge reserve) will decrease. In addition, in sealed nickel-metal hydride secondary batteries regulated by the positive electrode, when methylcellulose is decomposed by oxygen generated during overcharge, the charge reserve decreases according to the amount of decomposition, and hydrogen gas is generated at the end of charging, resulting in an increase in battery internal pressure. Will be invited.

  An excessive reduction in the amount of methylcellulose added is difficult because the resulting paste layer (active material layer) becomes extremely thin. After all, in a sealed nickel-metal hydride secondary battery regulated by the positive electrode, it is necessary to set a large charge reserve for the hydrogen storage alloy negative electrode in advance by the amount reduced by the decomposition of methylcellulose, and the energy density of the battery (maximum discharge amount / weight) Will fall.

Japanese Patent Laid-Open No. 10-3925

On the other hand, the use of highly polymerized methylcellulose having a weight average molecular weight of 1.2 to 1.3 × 10 ⁶ g / mol means that a hydrogen storage alloy powder, a binder, a thickener and water are mixed to form a paste electrode Forming a mixture, pulling up the metal plate forming the current collector from the paste tank to deposit the paste layer on both sides of the metal plate to form a paste-coated sheet, drying the paste layer to make an active material layer, Furthermore, the metal plate-adhered hydrogen storage alloy electrode manufacturing method that uses a roll press method to form a hydrogen storage alloy electrode has the following problems. Specifically, when the paste layer is applied to the current collector, an active material that is a paste component in the paste tank, a highly polymerized methylcellulose that is a thickener, PTFE (polytetrafluoroethylene) as a binder, Segregation of SBR (styrene butadiene rubber), PVDF (polyvinylidene fluoride) or a mixture thereof may occur, and the above-described battery performance may be locally degraded in the electrode plate. That is, when the paste layer is applied to the current collector, the viscosity of the thickener partially decreases locally, resulting in a portion with low adhesion, and peeling from the current collector due to charge / discharge. As a result, the battery electrical resistance may increase or the discharge capacity may decrease.

  The present invention has been made in view of the above problems, and its object is to apply a paste electrode mixture for forming a hydrogen storage alloy negative electrode capable of reducing the charge reserve of a nickel metal hydride secondary battery. It is in providing the method and the coating apparatus of a paste-form electrode mixture.

A method for applying a paste electrode mixture that solves the above problems is to mix a hydrogen storage alloy powder, a binder, a thickener, and water to form a paste electrode mixture. In this method, the paste electrode mixture is applied to at least one surface of the current collector by lifting the current collector from the stored paste tank. And, as the thickener, using methylcellulose having a weight average molecular weight of 0.2 × 10 ^{6 to} 1.0 × 10 ⁶ g / mol, when applying the paste electrode mixture to the current collector, Coating is performed in a state where a voltage is applied to the paste electrode mixture to increase the viscosity.

According to this configuration, since methylcellulose having a weight average molecular weight of 0.2 × 10 ^{6 to} 1.0 × 10 ⁶ g / mol is used as a thickener, it is easy to handle in terms of low viscosity per weight of solid content. In applying the paste-like electrode mixture to the current collector, the paste-like electrode mixture is partially prevented from partially reducing the viscosity of the thickening material and forming a portion with low adhesion. The However, this paste-like electrode mixture has a lower viscosity than when methylcellulose having a weight average molecular weight of 1.2 to 1.3 × 10 ⁶ g / mol is used, so that the current collector is lifted from the paste tank. When the paste electrode mixture is applied to the current collector, the thickness of the active material layer formed on the current collector does not reach the target thickness.

  However, since the paste-like electrode mixture configured as described above has properties of an electrorheological fluid, that is, an ER (Electro-Rheological) fluid, its (apparent) viscosity changes when a voltage is applied. In the coating method of the present invention, by applying a voltage to the paste electrode mixture having the properties of ER fluid to increase the viscosity, without increasing the amount of methylcellulose of the thickener, The paste-like electrode mixture can be applied to the current collector with a high viscosity, and the thickness of the active material layer formed on the current collector becomes the target thickness. Therefore, the hydrogen storage alloy negative electrode coated with the paste electrode mixture by the paste electrode mixture coating method has a suitable thickness and surface smoothness, and reduces the charge reserve of the nickel metal hydride secondary battery. be able to.

  After the current collector is pulled up from the paste tank, the current collector passes through the slit portion in order to equalize the thickness of the paste electrode mixture adhered to the current collector. In addition, a voltage is applied to the paste electrode mixture on the current collector. Therefore, the configuration for applying the voltage can be simply configured by, for example, providing the slit plate with an electrode plate provided so as to be able to contact the pasty electrode mixture attached on the current collector. it can.

  The voltage is applied by applying a DC voltage. The voltage applied to the paste electrode mixture on the current collector is not limited to a DC voltage, and may be an AC having a long positive / negative change period, but a DC voltage is preferred.

  A paste electrode mixture coating apparatus that solves the above problems includes a paste tank that stores a paste electrode mixture, and a current collector that is pulled up from the paste tank and coated on the surface with the paste electrode mixture In a paste electrode mixture coating apparatus comprising a paste coating part having a slit part through which a body can pass and an electrode heating and drying part provided after the paste coating part, the current collector is When passing through the slit part, a voltage application part for applying a voltage to the paste electrode mixture attached to the current collector was provided.

  Therefore, by using the coating apparatus of this configuration, the above-described paste electrode mixture coating method can be carried out, and the hydrogen storage alloy negative electrode coated with the paste electrode mixture has a suitable thickness and It has a paste coating amount (ie, basis weight) and surface smoothness, and can reduce the charge reserve of the nickel metal hydride secondary battery.

  The voltage application part is provided over the entire passage range of the current collector of the slit part. According to this structure, when applying the same voltage, a voltage application part can be made small.

  ADVANTAGE OF THE INVENTION According to this invention, the hydrogen storage alloy negative electrode which can reduce the charge reserve of a nickel hydride secondary battery can be formed.

Schematic of the electrode manufacturing apparatus of one Embodiment. (A) is a schematic diagram showing a state of dispersed particles when a DC voltage is not applied to the voltage application unit, and (b) is a schematic diagram showing a state of dispersed particles when a DC voltage is applied to the voltage application unit. Figure. Schematic which shows arrangement | positioning of the electrode plate of the voltage application part of another embodiment. The diagram which shows the relationship between the weight average molecular weight of methylcellulose, aqueous solution density | concentration, and a deposit paste weight.

Hereinafter, an embodiment embodying the present invention will be described with reference to FIGS. 1 and 2.
As shown in FIG. 1, the electrode manufacturing apparatus includes a metal foil supply unit 12 that supplies a metal foil 11 as a current collector, and a paste electrode mixture P on both surfaces of the metal foil 11 that is supplied from the metal foil supply unit 12. The coating apparatus 13 of the paste electrode mixture which coats, the roll press part 14, and the electrode cutting part 15 are provided.

  The metal foil supply unit 12 is configured to support the supply reel 16 around which the strip-shaped metal foil 11 is wound, and to drive the supply reel 16 to feed the metal foil 11 from the supply reel 16. .

  The roll press unit 14 includes an upper roll 14a and a lower roll 14b. The roll pressing unit 14 presses the metal foil 11 on which the active material layer is formed by applying the paste electrode mixture P by the coating apparatus 13 to a predetermined thickness. This is a hydrogen storage alloy negative electrode.

  The coating device 13 includes a paste tank 17 that stores the paste electrode mixture P, a paste coating unit 18 having a slit portion 18 a through which the metal foil 11 can pass, and an electrode heating and drying unit 19. The electrode heating / drying unit 19 is provided above the paste coating unit 18 so that the metal foil 11 coated with the paste electrode mixture P on both sides moves straight from the bottom to the top. More specifically, the electrode heating and drying unit 19 includes a pair of diaphragms 19a and 19b, and mechanical vibrations output from a vibrator (not shown) are converted into sound waves by the diaphragms 19a and 19b. The metal foil 11 is conveyed in a non-contact manner at a predetermined position by the radiation pressure of sound waves from the radiation surfaces of the diaphragms 19a and 19b.

  Tension rollers 20a, 20b, and 20c are provided between the metal foil supply unit 12 and the paste tank 17, and in the paste tank 17 and above the electrode heating and drying unit 19, respectively. A tension roller 20d is also provided between the tension roller 20c and the roll press unit 14. Each of the tension rollers 20a, 20b, 20c, and 20d is dried by heating the electrode after the metal foil 11 supplied from the metal foil supply unit 12 enters the paste tank 17 and then through the slit portion 18a of the paste coating unit 18. It is provided at a position that moves straight up in the part 19 and then smoothly moves to the roll press part 14.

  The paste coating part 18 is pulled up from the paste tank 17, and when the metal foil 11 with the paste electrode mixture P attached on both sides passes through the slit part 18a, the paste form attached to the metal foil 11 The voltage application part 21 which applies a voltage to the electrode mixture P is provided. The voltage application unit 21 applies a DC voltage to the paste electrode mixture P attached to the metal foil 11.

  The voltage application part 21 is provided over the whole passage range of the metal foil 11 of the slit part 18a. More specifically, the voltage application unit 21 has a pair of electrode plates 21a and 21b. One electrode plate 21a is electrically connected to the positive terminal 30a of the DC power supply device 30 by the anode wiring 31a, and the other electrode plate. 21b is electrically connected to the negative terminal 30b of the DC power supply device 30 by the cathode wiring 31b.

  The magnitude of the direct current supplied from the direct current power supply device 30 is the ratio of the hydrogen storage alloy powder, the binder, the thickener and the water constituting the paste electrode mixture P, and the methylcellulose constituting the thickener. An appropriate value is set according to the weight average molecular weight. This value is obtained in advance by a test.

  As the hydrogen storage alloy powder constituting the paste electrode mixture P, a misch metal-based material is suitable, but other materials such as a Zr-based or Ti-Mn-based material can be used. The average particle size of the hydrogen storage alloy powder is preferably 10 to 150 μm. If the average particle size is less than 10 μm, the cost increases. If the average particle size exceeds 150 μm, the reaction surface area of the hydrogen storage alloy electrode is insufficient. However, by setting the average particle size of the hydrogen storage alloy powder to 10 to 150 μm, such a situation does not occur, and a surface of the hydrogen storage alloy powder can be coated with a highly conductive metal film to be microencapsulated. it can. As the metal coating, nickel, copper, palladium, cobalt, or the like can be used. The weight of the metal coating can be 0.5 to 15%, more preferably 0.5 to 5% of the weight of the hydrogen storage alloy powder.

  As the binder, PTFE (polytetrafluoroethylene), SBR (styrene butadiene rubber), or a mixture thereof can be employed. PTFE (polytetrafluoroethylene) suppresses the volume change of the hydrogen storage alloy powder in the hydrogen storage alloy electrode due to hydrogen absorption and release, or resists the volume change and combines with the hydrogen storage alloy powder to suppress the collapse. To do. Since SBR has a large elastic deformation, even if the hydrogen storage alloy powder is deformed, it can be deformed following the deformation, and the hydrogen storage alloy powder is prevented from peeling from the current collector. In addition, as the binder, FEP, PCTFE, or the like can be used as the fluororesin fine powder, and silicon rubber, acrylic rubber, butadiene rubber, or the like can be used as the synthetic rubber system.

  The amount of the binder added can be 0.1 to 4%, more preferably 0.2 to 2% with respect to the hydrogen storage alloy powder. If the amount of binder is less than 0.1 wt%, the capacity of the hydrogen storage alloy powder will be reduced or reduced over time due to pulverization (reduction of cycle life), and if the amount of binder is more than 4 wt%, the capacity will be reduced and internal electricity will be reduced. Increases resistance loss.

As the thickener, methylcellulose having a weight average molecular weight of 0.9 × 10 ^{6 to} 1.0 × 10 ⁶ g / mol is used. The addition amount of the solid content of methylcellulose as the thickener can be 0.1 to 1 wt% with respect to the hydrogen storage alloy powder. If the amount of methyl cellulose is less than 0.1 wt%, the thickness of the paste layer applied to the current collector (metal foil 11) becomes thin. If the amount of methyl cellulose is more than 1 wt%, the surface smoothness of the formed paste layer is reduced. As a result, the electrode resistance increases.

Next, the manufacturing method of the hydrogen storage alloy negative electrode by the electrode manufacturing apparatus comprised as mentioned above is demonstrated.
Various concentrations of a methylcellulose aqueous solution having a weight average molecular weight of 0.9 × 10 ⁶ g / mol used as a thickener when preparing the paste electrode mixture P are 60SH-8000 manufactured by Shin-Etsu Chemical Co., Ltd. Was prepared by adjusting the concentration with water. Various concentrations of methylcellulose aqueous solution having a weight average molecular weight of 1.0 × 10 ⁶ g / mol were prepared by adjusting the concentration of 60SH-10,000 manufactured by Shin-Etsu Chemical Co., Ltd. with water.

  As shown in FIG. 1, the metal foil 11 fed from the supply reel 16 of the metal foil supply unit 12 is sent to the paste tank 17 of the coating apparatus 13 through the tension roller 20a. The metal foil 11 sent to the paste tank 17 is engaged with the tension roller 20b to change the moving direction vertically upward, and is guided to the paste coating unit 18 with the paste electrode mixture P attached to both surfaces. The

  In FIG. 1, the metal foil 11 passing through the slit portion 18 a of the paste coating unit 18 and the pair of electrode plates 21 a and 21 b of the voltage application unit 21 are illustrated with a gap between them. 11 passes through the slit portion 18a in a state where the paste-like electrode mixture P deposited on the metal foil 11 is in contact with the electrode plates 21a and 21b. The voltage application unit 21 applies a predetermined DC voltage to the paste electrode mixture P attached to the metal foil 11 passing through the slit portion 18 a by a DC current supplied from the DC power supply device 30.

  As shown in FIG. 2A, in a state where no voltage is applied between the electrode plates 21a and 21b, the particles 40 of the hydrogen storage alloy powder are dispersed throughout the paste electrode mixture P. is there. However, as shown in FIG. 2B, when a voltage is applied between the electrode plates 21a and 21b, the dispersed particles form a chain cluster between the electrode plates 21a and 21b. As a result, the flow resistance increases. The flow resistance of the paste electrode mixture P varies depending on the magnitude of the applied voltage, but a necessary viscosity change can be induced by applying a relatively low voltage. 2A and 2B, the particles 40 of the hydrogen storage alloy powder are schematically represented by a quadrangle, but of course, the particles 40 are not actually a quadrangle.

  As shown in FIG. 2B, in the state where a voltage is applied between the electrode plates 21a and 21b, the viscosity of the paste electrode mixture P existing between the electrode plates 21a and 21b increases. As a result, the amount of the paste-like electrode mixture P that adheres to both surfaces of the metal foil 11 that passes through the slit portion 18a of the paste coating portion 18 and is fed to the electrode heating / drying portion 19 is between the electrode plates 21a and 21b. Increased compared to a state in which no voltage is applied. In addition, the moving speed (pulling speed) of the metal foil 11 shall be 20-70 cm / min, for example.

  The paste-like electrode mixture P applied to the metal foil 11 by the paste coating unit 18 is dried by evaporating the moisture contained while passing through the electrode heating and drying unit 19, and the metal foil 11 is applied by coating. The pasted electrode mixture P is pressed by the roll press unit 14 in a dried state, and the active material layer is adjusted to an appropriate thickness. Thereafter, the metal foil 11 on which the active material layer is deposited with an appropriate thickness is cut into a predetermined length by the electrode cutting portion 15 to complete a hydrogen storage alloy negative electrode.

  In addition, in order to keep the surface of the paste-like electrode mixture P applied to both surfaces of the metal foil 11 smooth, the moisture contained in the paste-like electrode mixture P applied to both sides of the metal foil 11 In the electrode heating and drying unit 19 from the tension roller 20b to the tension roller 20c that uniformly evaporates, the metal foil 11 is conveyed in a non-contact manner at a predetermined position.

According to this embodiment, the following effects can be obtained.
(1) The paste electrode mixture is applied by mixing hydrogen storage alloy powder, binder, thickener and water to form the paste electrode mixture P, and storing the paste electrode mixture P. The current collector (metal foil 11) is pulled up from the paste tank 17 and the paste electrode mixture P is applied to both sides of the current collector. And, as a thickener, methylcellulose having a weight average molecular weight of 0.9 × 10 ^{6 to} 1.0 × 10 ⁶ g / mol is used, and at the time of applying the paste electrode mixture P to the current collector, it is pasty. Coating is performed in a state where a voltage is applied to the electrode mixture P to increase the viscosity.

Since methyl cellulose having a weight average molecular weight of 0.9 × 10 ^{6 to} 1.0 × 10 ⁶ g / mol is used as a thickener, it is easy to handle because of its low viscosity per solid content, and it is a paste electrode mixture When applying P to the current collector (metal foil 11), the paste-like electrode mixture P is partially prevented from partially reducing the viscosity of the thickening material and forming a portion with low adhesion. Is done.

Moreover, since the paste-like electrode mixture P has a lower viscosity than the case where methylcellulose having a weight average molecular weight of 1.2 to 1.3 × 10 ⁶ g / mol is used as a thickener, a current collector is simply used. When the paste electrode mixture P is pulled up from the paste tank 17 and applied to the current collector, the thickness of the active material layer formed on the current collector does not reach the target thickness.

  However, since the paste-like electrode mixture P configured as described above has the property of an electrorheological fluid, that is, an ER (Electro-Rheological) fluid, its (apparent) viscosity increases when a voltage is applied. And by applying a voltage to the paste-like electrode mixture P having the properties of ER fluid to increase the viscosity, the paste-like electrode mixture can be used without increasing the amount of the thickening agent methylcellulose. The current collector can be applied to the current collector in a high viscosity state, and the thickness of the active material layer formed on the current collector becomes the target thickness. Therefore, the hydrogen storage alloy negative electrode coated with the paste electrode mixture by the paste electrode mixture coating method has a suitable thickness and surface smoothness, and reduces the charge reserve of the nickel metal hydride secondary battery. be able to.

  (2) After the current collector (metal foil 11) is pulled up from the paste tank 17, the current collector is slit to make the thickness of the paste electrode mixture P attached to the current collector uniform. When passing through the portion 18a, a voltage is applied to the paste electrode mixture P on the current collector. Therefore, the configuration for applying the voltage is simple, for example, by providing the slit portion 18a with the electrode plates 21a and 21b provided so as to be in contact with the paste electrode mixture P attached to the current collector. Can be configured.

  (3) A DC voltage is applied to the paste electrode mixture P on the current collector (metal foil 11). The voltage applied to the paste electrode mixture on the current collector is not limited to a DC voltage, but may be an AC having a long positive / negative change period, but the DC voltage is easier to apply the voltage. Become.

  (4) Paste electrode mixture coating device 13 includes paste tank 17 storing paste electrode mixture P, and a collection of paste electrode mixture P applied to the surface by being pulled up from paste tank 17. The paste coating part 18 which has the slit part 18a which an electric body (metal foil 11) can pass, and the electrode heating drying part 19 provided after the paste coating part 18 are provided. Furthermore, the coating apparatus 13 includes a voltage application unit 21 that applies a voltage to the paste electrode mixture P attached to the current collector when the current collector passes through the slit portion 18a. Therefore, the coating apparatus 13 can carry out the above-described method for applying the paste electrode mixture P, and the hydrogen storage alloy negative electrode to which the paste electrode mixture P is applied has a suitable thickness and paste application. It has a deposited amount (ie, basis weight) and surface smoothness, and can reduce the charge reserve of the nickel metal hydride secondary battery.

  (5) The voltage application part 21 is provided over the whole passage range of the collector of the slit part 18a. According to this configuration, when a voltage of a necessary magnitude is applied to the paste electrode mixture P that passes through the slit portion 18a while attached to the current collector (metal foil 11), the voltage application unit 21 Can be reduced.

The embodiment is not limited to the above, and may be embodied as follows, for example.
The thickener is not limited to methyl cellulose having a weight average molecular weight of 0.9 × 10 ^{6 to} 1.0 × 10 ⁶ g / mol, but the weight average molecular weight is less than 0.9 × 10 ⁶ g / mol, and It may be 2 × 10 ⁶ g / mol or more of methylcellulose. The magnitude of the voltage applied in the voltage application unit 21 may be changed depending on the weight average molecular weight of methylcellulose to be used.

  The voltage applied to the paste electrode mixture on the current collector (metal foil 11) is not limited to a DC voltage, and may be an AC having a long positive / negative change period. However, a DC voltage is preferred.

  The application of the paste electrode mixture P is not limited to both sides of the current collector (metal foil 11), and may be on one side. When coating on one side of the current collector (metal foil 11), for example, on one side of the metal foil 11 pulled up from the paste tank 17 between the paste tank 17 and the paste coating unit 18 of the coating device 13. A scraping plate is provided in contact. In this case, of the paste electrode mixture P attached to both surfaces of the metal foil 11 pulled up from the paste tank 17, the paste electrode mixture P attached to one surface of the metal foil 11 is removed by the scraping plate. And the metal foil 11 from which the paste-like electrode mixture P adhering to one side is removed by the scraping plate is a pair of electrode plates 21a that the surface from which the paste-like electrode mixture P is removed constitutes the voltage application unit 21. , 21b, and the other electrode paste P which is attached to the metal foil 11 passes through the voltage application unit 21 and is transferred to the electrode heating / drying unit 19 in contact with the other.

  The electrode plates 21a and 21b constituting the voltage application unit 21 are not limited to the configuration provided over the entire passage range of the current collector (metal foil 11) of the slit portion 18a. For example, the electrode plate 21a, 21b may be provided on a part of the slit portion 18a.

  As shown in FIG. 3, the electrode plates 21 a and 21 b constituting the voltage application unit 21 may be provided so as to be immersed in the paste electrode mixture P stored in the paste tank 17. In the case of this configuration, in the paste-like electrode mixture P stored in the paste tank 17, the viscosity exists due to the DC voltage that exists between the electrode plates 21a and 21b and is applied between the electrode plates 21a and 21b. The paste electrode mixture P in an elevated state adheres to the metal foil 11. Therefore, after the paste-like electrode mixture P is attached to the metal foil 11, the paste-like electrode mixture P is applied with a voltage by the voltage application unit 21 in a state where the metal foil 11 has moved to the upper side of the paste tank 17. Compared to the case, an active material layer having a desired thickness can be easily formed on the metal foil 11.

The hydrogen storage alloy powder is not limited to a misch metal material, a Zr material, or a Ti—Mn material, but may be a conversion-type negative electrode active material that is a metal hydride (MHx).
O It may apply to the electrode manufacturing method in the lithium ion battery which uses the electrode using not only the hydrogen storage alloy electrode of a nickel metal hydride secondary battery but a polymer thickener.

  P ... Paste electrode mixture, 11 ... Metal foil as current collector, 13 ... Coating device, 17 ... Paste tank, 18 ... Paste coating part, 18a ... Slit part, 19 ... Electrode heating and drying part, 21 ... Voltage application unit.

Claims (6)

A hydrogen storage alloy powder, a binder, a thickener and water are mixed to form a paste electrode mixture, and a current collector is pulled up from a paste tank storing the paste electrode mixture, and the paste electrode mixture is extracted. In the coating method of the paste electrode mixture in which the agent is applied to at least one side of the current collector,
Methyl cellulose having a weight average molecular weight of 0.2 × 10 ^{6 to} 1.0 × 10 ⁶ g / mol is used as the thickening material, and the paste is mixed with the paste electrode mixture when applied to the current collector. A method for applying a paste-like electrode mixture, comprising applying a voltage to the electrode-like electrode mixture to cause an increase in viscosity.   After the current collector is pulled up from the paste tank, the current collector passes through the slit portion in order to equalize the thickness of the paste electrode mixture adhered to the current collector. The method for applying a paste electrode mixture according to claim 1, wherein a voltage is applied to the paste electrode mixture on the current collector.   The method of applying a paste electrode mixture according to claim 1 or 2, wherein the voltage is applied by applying a DC voltage.   A paste tank for storing a paste electrode mixture, a paste coating part having a slit portion through which a current collector pulled up from the paste tank and coated with the paste electrode mixture on the surface can pass, In a paste electrode mixture coating apparatus comprising an electrode heating and drying section provided after the paste coating section, the paste electrode mixture is pulled up from the paste tank and coated on the surface thereof. A paste-like electrode comprising a voltage application unit that applies a voltage in contact with the paste-like electrode mixture attached to the current collector when the current passes through the slit portion Mixing agent coating equipment.   The said voltage application part is a coating apparatus of the paste-form electrode mixture of Claim 4 provided over the whole passage range of the said collector of the said slit part.   The said voltage application part is a coating device of the paste-form electrode mixture of Claim 4 or Claim 5 which applies a DC voltage.

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