Abstract:
The present invention provides a manufacturing device of electrochemical cell components in a battery comprising a preliminary dip tank, baking box, main dip tank, and dipping device, drying tower and consolidating device. The present invention also provides a process for manufacturing electrochemical cell components in a battery comprising applying electrode materials over metal current collector webs or carbon (or glass) fiber fabric webs with dipping, baking and consolidating steps to make various kinds of electrochemical cell components in a battery (e.g. a cathode, anode, and separator) for use in subsequent processes of making a battery.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention relates to a device and process for manufacturing battery components, more particularly, to a manufacturing device of electrochemical cell components in a secondary battery and a process for making the same.  
         BACKGROUND OF THE INVENTION  
         [0002]    With the fast development of integrated circuit technology, portable electronic products (such as mobile phone, notebook computer, etc.) require high-performance in function, but lighter in weight and thinner, smaller and various in shape. Therefore, the price of a power source, the density of electrical energy (the dimension of a power supply) and the stability of the source are always a major subject of research in the development of the applications. In view of electrical energy, voltage and environmental protection, traditional batteries (like carbon-zinc, alkaline, mercury, or lithium batteries) are gradually replaced by secondary batteries capable of running for longer time and being charged repeatedly. Moreover, in some fields of application, like battery-powered vehicles, aircraft, microelectronic devices and wireless power supplies, secondary batteries provide broader scope for the development in the future.  
           [0003]    Generally, the electrochemical cell components in a battery comprise the following parts: an anode current collector web, an anode, a diaphragm, a cathode, and a cathode current collector web. Conventionally, the materials of interest are horizontally applied to a substrate (or fabric web) in industrially manufacturing the cell components in a battery to form the electrodes or separators. However, in case of horizontally coating, the applied materials (e.g. high density metal oxides in a polymer secondary battery) will precipitate during a baking process. In other words, the amount of solid particles in the applied materials near the substrate will be much higher than that near the surface layer, and the solid particles near the substrate will peel after coating. In addition, in a pressing process of making a battery, since the amount of particles is high and the adhesive is relatively insufficient, the electrode and separator cannot well combine with each other. Moreover, in the baking process, a solvent can evaporate only from a side of the substrate, and the evaporated surface will form a film of preventing further evaporation. If the baking temperature is too high, the surface is apt to being cracked. If the baking temperature is too low, the production speed will slow down for sufficiently drying and the particles in the applied materials will precipitate due to the long baking period.  
           [0004]    The vertically dipping method did improve the wetting problem and thus increasing the adhesion between the adhesive and the substrate, but the yield is still unsatisfied. As a result, there is still a need to find an improved manufacturing device and process of electrochemical cell components in a battery to solve the problems currently met in the industry; that is, poor yield or high inner electrical resistance results from poor adhesion between the electrodes.  
         SUMMARY OF THE INVENTION  
         [0005]    The present invention provides a device of manufacturing electrochemical cell components in a battery that integrates several improved device to sufficiently solve the problem of joining electrodes or separator of non-conductive polymer with a substrate. The present invention also provides a process for manufacturing an electrochemical cell components in a battery, by use of pretreatments such as wetting, cleaning and/or gluing, a specific design in a drying device that has vertical laminate flows and subsequent heating and consolidating device, to raise the overall product reliability of the electrochemical cell components in a battery and thus increase the yield. According to the present invention, the complexity of the manufacturing process can be simplified. For example, by changing different batches of solutions in a single dip tank or in separate dip tanks, different products, like anodes, cathodes; or separators, etc., can be made by the same manufacturing device. According to the present invention, the device for manufacturing the electrochemical cell components, which are made of a length of the substrate, comprises a plurality of spools in a unwinding device; a preliminary dip tank which contains liquid materials for cleaning and/or gluing surfaces of the substrate; a first coating device comprising a plurality of rollers contacting with the substrate for conveying the substrate through the liquid materials in the preliminary dip tank; a baking box for drying the dip-coated substrate; a main dip tank which contains a solution which includes a solvent for a cathode, an anode or a separator; a second coating device comprising a plurality of rollers in contact with the substrate which travels through the liquid material; agitating blades for stirring the solution, and a shield disposed between the rollers and the agitating blade to protect the agitating blades from the damage by falling objects; a plurality of squeezing rollers for closely joining the coated materials in the solution with the substrate and for uniformly distributing the thickness of the coating; a vertical drying device comprising a heating device, preferabl a heating device with multi-section radiant heating elements and hot-air inlet(s) and outlet(s); a consolidating device comprising a pair of heating rollers for rolling and consolidating the substrate that travels from the vertical drying device; and a spool in a fabric collector for collecting the solvent-coated and -curried electrochemical cell components about the spools for subsequent processing of making a battery.  
           [0006]    These and other objects, features and advantages will be clearly shown in the following more particular description of preferred embodiments. While we have shown and described specific embodiments of the present invention, further modifications and improvements will occur to those skilled in the art. Therefore, it is understood that this invention is not limited to the shown particular forms and covers in the appended claims all modifications that do not depart from the spirit and scope of this invention. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]    [0007]FIG. 1 shows a schematic diagram of a device for manufacturing electrochemical cell components according to the present invention.  
         [0008]    [0008]FIG. 2 shows a preliminary dip tank and a baking box.  
         [0009]    [0009]FIG. 3 shows a schematic diagram of a main dip device.  
         [0010]    [0010]FIG. 4 shows a schematic diagram of a conveying line in the drying tower and heat laminate flow.  
         [0011]    [0011]FIG. 5 shows a schematic diagram of a consolidating device in a closed chamber. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0012]    The present invention discloses a manufacturing device and process of electrochemical cell components in a battery. The present invention is directed to eliminating defects that cannot efficiently increase yield in the conventional manufacturing process, and successfully solving the aforementioned problems of joining the components and unfavorable outcomes.  
         [0013]    [0013]FIG. 1 is a schematic diagram of the manufacturing device of electrochemical cell components in a battery built according to the present invention. An unwinding device  100  includes a plurality of spools  101  to supply an original substrate  10 . A fabric-storing device  102  is designed to change the spools  101  for storing the original substrate  10  without interrupting the conveyance of the original substrate  10  in the production line. A pretreatment device  200  comprises one or more preliminary dip tanks  202  and baking boxes  204 . Subsequently, a main dip device  300  is used to apply an electrode material or non-conductive polymer on the original substrate  10 . Afterward, the coated substrate  20  with the electrode material (or non-conductive material) thereon vertically travels into a vertical drying tower  400  where there is hot air from a blast furnace  600  in the bottom of the tower  400  through the whole drying tower  400  and out of the top of the tower  400 . The coated substrate  20  conveyed from the top of the drying tower  400  then enters a closed consolidating device  500  to closely join the coating material with the coated substrate  20 . Lastly, cell components  30  made of the coated substrate  20  are wound about a spool  701  in the winder  700  for facilitating subsequent processes. Afterward, the resulting cell components in the battery can be made into a semi-product of a battery by way of the conventional hot-rolling process, or by the hot pressing disclosed in the inventor&#39;s previous ROC Patent Application No. 89105811, which the hot pressing comprises cutting the cell components into components of a suitable size, stacking and pressing the cut components.  
         [0014]    [0014]FIG. 2 shows a pretreatment device  200  of the original substrate  10 . The device  200  includes at least one preliminary dip tank  202 , a baking box  204  and a plurality of rollers  205   206   207  and  208 . The function of the preliminary dip tank  202  is to clean an oil-contaminated or the oxidized layer over the surfaces of the original substrate  10  (nonwoven fabric or metal web) due to storage or transportation. These detrimental substances may result in poor adhesion of the coating material to the original substrate  10  or increase the inner electrical resistance of the battery. In addition, one or more preliminary dip tank  202   a  may be optionally added for applying a glue to the original substrate  10  so as to enhance the coating uniformity and adhesion of the subsequently coating electrode materials. After the preliminary dipping step, the original substrate  10  is baked in the baking box  204 .  
         [0015]    [0015]FIG. 3 illustrates a schematic diagram of the main dip device  300  of the present invention. The dried original substrate  10  is then transported to a main dip tank  309  for a primary coating process. The main dip tank  309  comprises a plurality of rollers  302 ,  304 ,  306  and  308  for changing the moving direction of the substrate. The main dip tank  309  contains a solution  310 , an agitating blade  311  for stirring the solution  310 , which contains a cathode, anode, or separator material to be coated. The purpose of stirring the solution  310  is to prevent the solutes with a high specific weight from precipitation in the solution  310  and unevenly coating the original substrate  10 . A shield  312  may be provided between the agitating blade  311  and the original substrate  10 , to avoid interrupting the production process resulting from heavier objects (such as the solute or broken substrates) falling onto the blade  311 . After dipping, the original substrate  10  travels through a pair of squeezing rolls  316  to uniformly and compactly coat the original substrate  10  with the solutes such as the electrode materials in the solution  310 .  
         [0016]    As shown in FIG. 4, the coated substrate  20  moves upward into the vertical drying tower  400 . The drying tower  400  comprises heating devices  402  (preferabl a radiant heating source) which may be divided into a plurality of heating zones to optimize the heating efficacy. In addition to the heating device  402 , hot air from a blast furnace  600  is introduced through an entrance  404  for the coated substrate  20  and is discharged from a hot-air pipe  406 . The purpose of introducing hot air is to form laminate flows in the drying tower  400  as a heat-transfer media, and to take away and recycle evaporated solvents simultaneously. Because the traveling direction of the coated substrate  20  is opposite to that of gravity, the problem of precipitation on the substrate encountered in the prior art can be avoided, and the purpose of stabilizing the quality of the battery is achieved. Moreover, because of the baking box with double-sided baking capability, the solvent in the solution applied on both sides of the coated substrate  20  can be uniformly evaporated. Since the area of evaporation is twice as that in a horizontal machine, the production speed increases.  
         [0017]    [0017]FIG. 5 shows a consolidating device  500  that comprises a pair of heatable squeezing rollers  502  and exhaust pipes  504  and  506 . In a closed chamber, the solutes (e.g. electrode materials) can uniformly distributed on the substrate to form cell components  30  by thermal energy from the heatable squeeze rollers  502 , as Well as by that of the hot air exhausted from the drying tower  400  and the heat kept in the coated substrate  20 . The reason for locating the consolidating device  500  at the top of the drying tower  400  is to well take advantage of hot air and to roll the coated substrate  20  before cooling for saving energy and reducing the cost.  
         [0018]    Finally, the formed cell components  30  are rolled into a fabric spool  701  by a fabric winder  700  for subsequent processes.  
         [0019]    The efficacies of the manufacturing device of electrochemical cell components in a battery according to the present invention are as follows:  
         [0020]    I. Introduction of the Pretreatment Device:  
         [0021]    The pretreatment device is used to clean the substrate, e.g. a copper or aluminum metal web, to keep the substrate from contaminants like an oil. The contamination will result in an uneven distribution of the glue as a glue solution is applied over the substrate in the dip tank. In addition, the preliminary dip tank can be used for pretreatment of the surfaces made of the copper or aluminum metal web. If necessary, the copper or aluminum metal web can be coated with a layer of primer to enhance the surface adhesion of the web. The preliminary dip tanks may be arranged in series to achieve the objects of the present invention mentioned above.  
         [0022]    II. Enhancement in Uniform Temperature Control of the Vertical Baking Box:  
         [0023]    With the preferable radiant heating elements, the thermal energy can be radiatively transferred from the surfaces of heating elements to the object to be dried. At the same time, hot air is introduced into the baking box to take away the solvent and leave the solutes (e.g. electrode materials) behind. The introduction of hot air can also form the laminate flows that act as a heat-transfer medium to provide efficiently thermal energy for drying. The flow rate of the introduced hot air is pre-calculated to sufficiently evaporate the solution on the substrate and to cure the solute of interest disposed on the substrate, without an adverse effect of high temperature on the coating. In addition, the heating elements in the baking box can be divided into multiple sections that independently control the drying temperature to increase the baking efficiency. The above designs can be applied in combination to achieve the object of uniformly distributing temperature or drying, and thus increase the throughout.  
         [0024]    III. Agitation in the Main Dip Tank:  
         [0025]    The purpose of agitating is to prevent the precipitation of the solutes with a high specific weight, and uniformly distribute the solutes in the solution of the main dip tank. Moreover, a shield is equipped above the agitating blade for protection.  
         [0026]    IV. Consolidation Process:  
         [0027]    In consolidation, it is necessary to exercise a pressure on the substrate and heat the substrate by the squeezing rollers. According to the present invention, the consolidating device is set on the top of the baking box in order to efficiently recycle the thermal energy dissipating from the baking box in the closed chamber, and thus to reduce the cost of the battery products.  
         [0028]    V. The Reduction of Investment in Production Equipment:  
         [0029]    According to the present invention, an electrically conductive substrate, e.g. current collector web or carbon-fiber nonwoven fabric web, can be directly coated with the materials such as a cathode or anode, or a substrate can be coated with materials, e.g. polyethylene or polyethylene terephthalate (PET) as a separator film, so that a coating carrier like a releasing film can be eliminated and cost can be reduced. Moreover, the same manufacturing device can be used for producing the current collector web-contained electrodes or separators by simply changing the coating solution in the dip tanks.  
         [0030]    By the foregoing description, various processes embodying the present invention have been disclosed. However, numerous modifications and substitutions may be made without deviating from the scope of the present invention. Therefore, the above illustration is to disclose the present invention but not to limit the scope thereof.