JP2012204279A - Secondary battery manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a secondary battery manufacturing method capable of inexpensively manufacturing a secondary battery in a shorter time.SOLUTION: A secondary battery 1 comprises an electrode plate laminate 4, and a container 6 for housing the electrode plate laminate 4 together with an electrolyte solution 5. A method of the secondary battery 1 includes a separator lamination step, an electrolyte solution permeation step, an electrode plate lamination step, and a step for housing the electrode plate laminate 4 in the container 6 and injecting the electrolyte solution 5 in the container 6. In the separator lamination step, a separator 7 is laminated on one of a positive electrode plate 2 and a negative electrode plate 3. In the electrolyte solution permeation step, the electrolyte solution 5 is permeated in the separator 7 from a side of the separator 7 opposite to one electrode plate. In the electrode plate lamination step, the other one of the positive electrode plate 2 and the negative electrode plate 3 is laminated on the side of the separator 7 opposite to one electrode plate, so as to form the electrode plate laminate 4.

Description

  The present invention relates to a method for manufacturing a secondary battery having a positive electrode plate and a negative electrode plate laminated via a separator.

  A chargeable / dischargeable secondary battery is used as a driving power source for portable electronic devices such as a mobile phone, a notebook computer, a video cam recorder, and a digital still camera. In recent years, secondary batteries have been adopted in electric vehicles and household storage batteries, and the demand for secondary batteries is increasing. In order to cope with the increase in demand for secondary batteries, it is desired to improve the productivity of secondary batteries.

  The structure and manufacturing method of the secondary battery will be described with reference to FIGS. FIG. 4 is a cross-sectional view of the structure of the secondary battery.

  As shown in FIG. 4, the secondary battery 1 includes an electrode plate laminate 4 in which a positive electrode plate 2 and a negative electrode plate 3 are laminated, and a container 6 that houses the electrode plate laminate 4 together with an electrolyte solution 5. ing. A separator 7 is provided between the positive electrode plate 2 and the negative electrode plate 3. The separator 7 is formed using a material capable of penetrating liquid, such as a porous resin film, and the electrolyte solution 5 penetrates the separator 7. As the ions in the electrolyte solution 5 pass through the separator 7 and reciprocate between the positive electrode plate 2 and the negative electrode plate 3, the secondary battery 1 is charged and discharged.

  FIG. 5 is a diagram for explaining a method of manufacturing a secondary battery. First, as shown in FIG. 5A, the positive electrode plate 2 and the negative electrode plate 3 having a predetermined size are laminated via the separator 7 to form the electrode plate laminate 4. Next, as shown in FIG. 5 (b), the electrode plate laminate 4 is sandwiched between a pair of container main bodies 6a and 6b having recesses, and the edges of the pair of container main bodies 6a and 6b are joined to each other. At this time, a part of the edges of the pair of container main bodies 6a and 6b is not joined. Subsequently, as shown in FIG. 5 (c), the electrolyte solution 5 is injected into the container 6 from the unjoined part of the edges of the pair of container main bodies 6 a and 6 b, and the electrolyte solution 5 flows through the container 6. Fill with. Finally, a part of the edges of the pair of container main bodies 6a and 6b that are not joined is joined, and the electrode laminate 4 is accommodated in the container 6 together with the electrolyte solution 5 to complete the secondary battery 1.

  In such a secondary battery manufacturing method, when the container 6 is filled with the electrolyte solution 5 in a relatively short time, air remains in the micropores existing in the separator 7, and the electrolyte solution 5 sufficiently penetrates the separator 7. There are things that do not.

  The reason why air remains in the minute holes of the separator 7 is that there is almost no gap or only a very small gap (25 μm or less) between the separator 7 and the positive electrode plate 2 or the negative electrode plate 3. . When the container 6 is filled with the electrolyte solution 5 in a relatively short time, the electrolyte solution 5 starts to penetrate the separator 7 from the entire periphery of the separator 7. Therefore, the air in the minute holes near the center of the separator 7 cannot escape from the periphery of the separator 7 to the outside. As a result, air remains in the minute hole near the center of the separator 7.

  When the electrolyte solution 5 does not sufficiently permeate the separator 7, ions in the electrolyte solution 5 that reciprocate between the positive electrode plate 2 and the negative electrode plate 3 decrease, so that the performance of the secondary battery (for example, operating voltage or (Electric capacity) decreases. Further, if charging / discharging is performed in a state where the electrolyte solution 5 is not sufficiently permeated, air remains in the separator 7, which may cause ignition from the separator 7.

  In order to sufficiently infiltrate the electrolyte solution 5 into the separator 7, the following method for injecting the electrolyte solution 5 into the container 6 has been proposed. In the electrolyte solution injection step of injecting the electrolyte solution 5 into the container 6, the container 6 is arranged so that the separator 7 is along the vertical direction (as shown in FIG. 5C), and half of the electrode plate laminate 4 is immersed. The electrolyte solution 5 is injected into the container 6. In this state, since the electrolyte solution 5 does not permeate the upper half of the separator 7 in the vertical direction, air near the center of the separator 7 easily escapes from the separator 7, and the electrolyte solution 5 penetrates to the vicinity of the center of the separator 7. . After the electrolyte solution 5 has penetrated to the vicinity of the center of the separator 7, the electrolyte solution 5 is again injected into the container 6 to fill the container 6 with the electrolyte solution 5. By injecting the electrolyte solution 5 into the container 6 in this manner, the air in the separator 7 can be extracted, and the electrolyte solution 5 can be sufficiently permeated into the separator 7. A method of continuously injecting a small amount of the electrolyte solution 5 into the container 6 may be used.

  However, in such a method, the electrolyte solution 5 must be left for a relatively long time until it penetrates to the vicinity of the center of the separator 7. In particular, a nonaqueous solution having a low affinity for the separator 7 is often used for the electrolyte solution 5. Therefore, the electrolyte solution 5 hardly penetrates into the separator 7.

  Furthermore, the positive electrode plate 2 and the negative electrode plate 3 often contain a carbon-based conductive material. The affinity of the non-aqueous solution for the carbon-based conductive material is relatively low. Therefore, when the positive electrode plate 2 or the negative electrode plate 3 and the separator 7 are close to each other, the carbon-based conductive material may prevent the electrolyte solution 5 from penetrating into the separator 7.

  Therefore, in a secondary battery in which a nonaqueous solution is used for the electrolyte solution 5 and the positive electrode plate 2 or the negative electrode plate 3 contains a carbon-based conductive material, the electrolyte solution 5 must be permeated into the separator 7 over a longer time. It was. As a result, the productivity of the secondary battery has been reduced. In view of this, Patent Documents 1 to 5 propose methods for manufacturing a secondary battery in which the electrolyte solution 5 can sufficiently permeate the separator 7 without reducing the productivity of the secondary battery.

  Patent Document 1 discloses a manufacturing method in which an electrolyte solution injection process is performed in a space in a vacuum state. By disposing the electrode laminate 4 in the space, the air in the separator 7 is extracted. Therefore, even if the container 6 is filled with the electrolyte solution 5 in a relatively short time, the electrolyte solution 5 can permeate to the vicinity of the center of the separator 7 without air remaining in the separator 7.

  Patent Document 2 discloses a method for manufacturing a secondary battery using a high affinity solvent having a relatively high affinity for the separator 7. A high affinity solvent is mixed into the electrolyte solution 5 to form a mixed solution of the high affinity solvent and the electrolyte solution 5, and the mixed solution is injected into the container 6. Since the mixed solution contains the high affinity solvent, the mixed solution can penetrate into the separator 7 in a relatively short time.

  In Patent Document 3, a manufacturing method of adding a functional group limiting agent that limits the number of functional groups present on the surfaces of the positive electrode plate 2 and the negative electrode plate 3, particularly the carbon-based conductive material, to a certain range is added to the positive electrode plate 2 and the negative electrode plate 3. Is disclosed. It is known that when the number of functional groups of the positive electrode plate 2 and the negative electrode plate 3 is limited, the affinity of the positive electrode plate 2 and the negative electrode plate 3 to the electrolyte solution 5 is improved. By limiting the number of functional groups of the positive electrode plate 2 and the negative electrode plate 3, the positive electrode plate 2 and the negative electrode plate 3 do not hinder the penetration of the electrolyte solution 5 into the separator 7, and the electrolyte solution 5 easily penetrates into the separator 7. Become. As a result, the electrolyte solution 5 can be sufficiently permeated into the separator 7 in a relatively short time.

  Patent Document 4 and Patent Document 5 disclose a method for manufacturing a secondary battery including a step of allowing a separator 7 to permeate a solvent having a relatively high affinity for the electrolyte solution 5 before the electrode plate laminate 4 is formed. ing. By soaking the solvent into the separator 7, the electrolyte solution 5 can easily penetrate into the separator 7 in the electrolyte solution injection step. Therefore, the time for the electrolyte solution injection step can be shortened.

WO99 / 41797 JP 2009-176598 A JP-A-2005-310764 JP 2003-308877 A JP 2007-280948 A

  However, the manufacturing method disclosed in Patent Document 1 requires a new device for forming a space in a vacuum state, such as a vacuum device. Therefore, a manufacturing apparatus becomes expensive and the manufacturing cost of a secondary battery becomes high.

  In addition, in the production methods disclosed in Patent Documents 2 to 5, since a new solvent such as a high affinity solvent or a functional group limiting agent is used, the material cost becomes high. Furthermore, a process for producing a new solvent is required, which may increase the production cost.

  Therefore, an example of the object of the present invention is to provide a secondary battery manufacturing method capable of manufacturing a secondary battery in a shorter time and at a lower cost.

  In order to achieve the above object, one aspect of the present invention accommodates an electrode plate laminate in which a positive electrode plate and a negative electrode plate are laminated via a separator infiltrated with an electrolyte solution, and an electrode plate laminate together with the electrolyte solution. A secondary battery including the container. In this aspect, a positive electrode plate, a negative electrode plate, and a step of preparing a separator in which an electrolyte solution does not permeate, a separator laminating step, an electrolyte solution permeating step, an electrode plate laminating step, and a container are prepared. Containing a body in a container and injecting an electrolyte solution into the container. In the separator stacking step, the separator is stacked on one of the positive electrode plate and the negative electrode plate. In the electrolyte solution infiltration step, the electrolyte solution is infiltrated into the separator from the side of the separator opposite to the one electrode plate. In the electrode plate lamination step, the other electrode plate of the positive electrode plate or the negative electrode plate is laminated on the side of the separator opposite to the one electrode plate to form an electrode plate laminate.

  According to the method for manufacturing a secondary battery of the present invention, a secondary battery can be manufactured in a shorter time and at a lower cost.

It is sectional drawing of the secondary battery manufactured by the manufacturing method which concerns on this invention. It is a figure for demonstrating the manufacturing method of the secondary battery which concerns on this invention. It is sectional drawing of the secondary battery which has an electrode plate laminated body by which a some positive electrode plate, a negative electrode plate, and a separator are laminated | stacked. It is sectional drawing for demonstrating the structure of a secondary battery. It is a figure for demonstrating the manufacturing method of the conventional secondary battery.

  Hereinafter, the manufacturing method of the secondary battery which concerns on embodiment of this invention is demonstrated in detail based on drawing.

  FIG. 1 is a cross-sectional view of a secondary battery manufactured by a manufacturing method according to an embodiment of the present invention. As shown in FIG. 1, the secondary battery 1 includes an electrode plate laminate 4 in which a positive electrode plate 2 and a negative electrode plate 3 are laminated, and a container 6 that houses the electrode plate laminate 4 together with an electrolyte solution 5. ing.

  A separator 7 is provided between the positive electrode plate 2 and the negative electrode plate 3. Contact between the positive electrode plate 2 and the negative electrode plate 3 is prevented by the separator 7. A gap may be provided between the positive electrode plate 2 and the separator 7 and between the negative electrode plate 3 and the separator 7. In addition, spacers (not shown) for securing the gap may be disposed between the positive electrode plate 2 and the separator 7 and between the negative electrode plate 3 and the separator 7.

  The positive electrode plate 2 includes a positive electrode current collector 2a and a positive electrode active material layer 2b disposed on the surface of the positive electrode current collector 2a on the separator 7 side. The negative electrode plate 3 includes a negative electrode current collector 3a and a negative electrode active material layer 3b disposed on the surface of the negative electrode current collector 3a on the separator 7 side. A carbon-based conductive material is used for the positive electrode active material layer 2b and the negative electrode active material layer 3b.

  The separator 7 is formed using a material capable of penetrating liquid, such as a porous resin film, and the electrolyte solution 5 penetrates the separator 7. As the ions in the electrolyte solution 5 pass through the separator 7 and reciprocate between the positive electrode plate 2 and the negative electrode plate 3, the secondary battery 1 is charged and discharged.

  Next, a method for manufacturing a secondary battery according to the first embodiment of the present invention will be described with reference to FIG. 2A to 2F are views for explaining a method for manufacturing a secondary battery according to the present embodiment.

  As shown in FIG. 2A, the worker or the manufacturing apparatus prepares the positive electrode plate 2, the negative electrode plate 3, and the separator 7 having a predetermined size. At this time, the electrolyte solution 5 (FIG. 1) does not penetrate into the separator 7. Therefore, when the separator 7 is prepared, the electrolyte solution 5 is not dripped from the separator 7 and consumption of the electrolyte solution 5 and contamination around the manufacturing apparatus are suppressed.

  Next, as shown in FIG. 2B, a separator stacking process for stacking the separator 7 on the positive electrode plate 2 is performed. In the separator stacking step, a spacer (not shown) for securing a gap between the positive electrode plate 2 and the separator 7 may be disposed between the positive electrode plate 2 and the separator 7.

  Subsequently, as shown in FIG. 2 (c), an electrolyte solution infiltration step is performed in which the electrolyte solution 5 is infiltrated into the separator 7 from the side of the separator 7 opposite to the positive electrode plate 2. As a method for infiltrating the electrolyte solution 5 into the separator 7, the positive electrode plate 2 and the separator 7 are arranged so as to cross the vertical direction, and the separator 7 is arranged above the positive electrode plate 2 in the vertical direction. The method of dripping the solution 5 is mentioned.

  In the electrolyte solution infiltration step, the negative electrode plate 3 is not laminated on the side of the separator 7 opposite to the positive electrode plate 2. Therefore, the air existing in the minute holes of the separator 7 can escape from the side of the separator 7 opposite to the positive electrode plate 2. Therefore, the electrolyte solution 5 can be permeated into the separator 7 in a shorter time than the case where the electrolyte solution 5 is permeated from the edge of the separator 7 sandwiched between the positive electrode plate 2 and the negative electrode plate 3.

  Moreover, the electrolyte solution 5 can be dripped at a plurality of locations on the surface of the separator 7 opposite to the positive electrode plate 2. Therefore, the electrolyte solution 5 can be permeated into the separator 7 in a shorter time as compared with the case where the electrolyte solution 5 is permeated from the edge of the separator 7.

  The method of infiltrating the electrolyte solution 5 into the separator 7 is not limited to the method of dropping the electrolyte solution 5 from above the separator 7 in the vertical direction. For example, the positive electrode plate 2 and the separator 7 may be disposed along the vertical direction, and the electrolyte solution 5 may be infiltrated into the separator 7 by spraying the electrolyte solution 5 in the form of a mist to the separator 7.

  The amount of the electrolyte solution 5 that permeates the separator 7 is desirably substantially equal to the maximum amount of the electrolyte solution 5 that can be absorbed by the separator 7. This is because when the amount of the electrolyte solution 5 exceeding the maximum amount is dropped onto the separator 7, the electrolyte solution 5 overflows from the separator 7. In addition, when the amount is less than the maximum amount, the electrolyte solution 5 does not sufficiently permeate the separator 7 and air may remain in the separator 7.

  When the electrolyte solution 5 has permeated the separator 7, as shown in FIG. 2 (d), an electrode plate stacking step is performed in which the negative electrode plate 3 is stacked on the side of the separator 7 opposite to the positive electrode plate 2. In this way, the electrode plate laminate 4 in which the positive electrode plate 2 and the negative electrode plate 3 are laminated via the separator 7 is formed. A spacer (not shown) for securing a gap between the separator 7 and the negative electrode plate 3 may be disposed between the separator 7 and the negative electrode plate 3.

  In this embodiment, the separator 7 is laminated on the positive electrode plate 2 in the separator lamination step (FIG. 2B), but the separator 7 may be laminated on the negative electrode plate 3 in the separator lamination step. In this case, the positive electrode plate 2 is stacked on the separator 7 in the electrode plate stacking step (FIG. 2D).

  Next, as shown in FIG. 2 (e), a container 6 for preparing the electrode laminate 4 together with the electrolyte solution 5 is prepared, and the electrode laminate 4 is accommodated in the container 6. Examples of the container 6 include a structure formed by joining a pair of container main bodies 6a and 6b each having a recess. The electrode plate laminate 4 is accommodated in the container 6 by arranging the electrode plate laminate 4 between the pair of container main bodies 6 a and 6 b and joining the edges of the pair of container main bodies 6 a and 6 b to each other.

  Finally, as shown in FIG. 2F, an electrolyte solution injection step for injecting the electrolyte solution 5 into the container 6 is performed. An opening 8 is formed in a part of the container 6, and the electrolyte solution 5 is injected into the container 6 from the opening 8. The opening 8 may be formed by not joining a part of the edges of the pair of container main bodies 6a and 6b in the step of housing the electrode plate laminate 4 in the container 6 (FIG. 2 (e)).

  The electrode plate laminate 4 can be accommodated in the container 6 together with the electrolyte solution 5 by joining the opening 8 after injecting the electrolyte solution 5.

  Further, in the electrolyte solution injection step, the electrolyte solution 5 can be permeated into the separator 7 in a short time by injecting the electrolyte solution 5 from the direction intersecting with the stacking direction of the electrode plate laminate 4. This is suitable when the separator 7 is less than the maximum amount of the electrolyte solution 5 that can be absorbed in the electrolyte solution permeation step (FIG. 2C). This is because by injecting the electrolyte solution 5 in this way, the electrolyte solution 5 easily passes between the positive electrode plate 2 and the negative electrode plate 3.

  In order to inject the electrolyte solution 5 from the direction crossing the stacking direction of the electrode laminate 4, the secondary battery is manufactured in the present embodiment by the following method.

  That is, when the electrode plate laminate 4 is accommodated in the container 6 (FIG. 2 (e)), the direction in which the pair of container main bodies 6a and 6b face each other and the lamination direction of the electrode plate laminate 4 are parallel to each other. The electrode plate laminate 4 was disposed between the pair of container main bodies 6a and 6b. Furthermore, the opening 8 was formed by not joining a part of edge of a pair of container main body 6a, 6b. The opening 8 located in the direction which cross | intersects with respect to the lamination direction of the electrode laminated body 4 of the container 6 can be formed easily.

  Further, the container 6 was arranged so that the opening 8 was positioned on the upper side in the vertical direction, and the electrolyte solution 5 was injected into the container 6 toward the lower side in the vertical direction. The electrolyte solution 5 can be injected into the container 6 without the electrolyte solution 5 leaking from the container 6.

  According to the method for manufacturing a secondary battery according to the present invention, the electrolyte solution 5 has already penetrated into the separator 7 in the electrolyte solution injection step. That is, the separator 7 is familiar with the electrolyte solution 5, and the affinity of the electrolyte solution 5 for the separator 7 is improved.

  Therefore, in the electrolyte solution injection step, the time for allowing the electrolyte solution 5 to permeate the separator 7 becomes unnecessary or shorter. As a result, it is possible to inject the electrolyte solution 5 into the container 6 in a shorter time than in the case where the electrolyte solution 5 is infiltrated into the separator 7 in the electrolyte solution injection step.

  In the method for manufacturing the secondary battery shown in FIG. 4, the electrolyte solution injection process requires 8 hours. However, in the method for manufacturing the secondary battery according to the present embodiment, the electrolyte solution injection process can be completed in 2 hours. did it.

  In addition, according to the manufacturing method of the present invention, a new device such as a vacuum device for removing the air in the separator 7 is not required. Furthermore, a new solvent such as a high affinity solvent or a functional group restricting agent for making the electrolyte solution 5 easily penetrate into the separator 7 is not required. Therefore, a secondary battery can be manufactured at a lower cost.

  In the present embodiment, the secondary battery including one positive electrode plate 2, negative electrode plate 3, and separator 7 has been described. However, an electrode plate stack in which a plurality of positive electrode plates 2, negative electrode plates 3, and separators 7 are stacked. The present invention can also be applied to a secondary battery having a body (FIG. 3).

  FIG. 3 is a cross-sectional view of a secondary battery having an electrode plate laminate in which a plurality of positive electrode plates 2, negative electrode plates 3, and separators 7 are laminated. When the secondary battery 1 shown in FIG. 3 is manufactured, the separator lamination step, the electrolyte solution infiltration step, and the electrode plate lamination step are repeated in this order after the electrode plate lamination step, and a desired number of positive electrode plates 2 are obtained. The negative electrode plate 3 and the separator 7 are laminated.

DESCRIPTION OF SYMBOLS 1 Secondary battery 2 Positive electrode plate 3 Negative electrode plate 4 Electrode plate laminated body 5 Electrolyte solution 6 Container 7 Separator 8 Opening

Claims (5)

An electrode plate laminate in which a positive electrode plate and a negative electrode plate are laminated via a separator;
A container containing the electrode plate laminate together with an electrolyte solution, and a manufacturing method of a secondary battery comprising:
Preparing the positive electrode plate, the negative electrode plate, the separator not penetrating the electrolyte solution, and the container;
A separator laminating step of laminating the separator on one of the positive electrode plate or the negative electrode plate;
An electrolyte solution infiltration step for infiltrating the electrolyte solution into the separator from the side of the separator opposite to the one electrode plate;
An electrode plate stacking step of forming the electrode plate laminate by stacking the other electrode plate of the positive electrode plate or the negative electrode plate on the side of the separator opposite to the one electrode plate;
A method of manufacturing a secondary battery, comprising: an electrolyte solution injection step of accommodating the electrode laminate in the container and injecting the electrolyte solution into the container.   In the electrolyte solution permeation step, the one electrode plate and the separator are arranged so as to intersect with the vertical direction, and the separator is arranged on the upper side in the vertical direction with respect to the one electrode plate, and the electrolyte from above in the vertical direction of the separator. The method for producing a secondary battery according to claim 1, wherein the solution is dropped.   The method for manufacturing a secondary battery according to claim 2, wherein in the electrolyte solution permeation step, the electrolyte solution is dropped into at least two locations of the separator.   In the electrolyte solution injection step, an opening is formed in a part of the container in a direction intersecting with the stacking direction of the electrode plate laminate, and the container is arranged so that the opening is positioned on the upper side in the vertical direction. The method for manufacturing a secondary battery according to claim 1, wherein the electrolyte solution is injected into the container downward in the vertical direction. Each of the electrode laminates includes at least two of the positive electrode plate, the negative electrode plate, and the separator;
The manufacturing method of the secondary battery of any one of Claim 1 thru | or 4 including repeatedly performing the said separator lamination process, the said electrolyte solution osmosis | permeation process, and the said electrode plate lamination process in this order.

Images