JP2019192508A - Electrode plate manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrode plate manufacturing method capable of obtaining an electrode plate by satisfactorily cutting the electrode original plate in a simple process without impairing battery performance. An electrode plate for a battery using a non-aqueous electrolyte and an electrode stack is manufactured. First, a liquid supply step of supplying a liquid to the electrode active material layer of the electrode original plate 1 obtained by coating the electrode foil with the electrode active material layer is performed. Next, a cutting step is performed in which the portion of the electrode original plate 1 after the liquid supply step where the liquid is supplied to the electrode active material layer is cut to form the electrode plate 3 of a size to be laminated in the electrode laminate. Here, as the liquid supplied in the liquid supply step, a liquid having a component common to the solvent of the non-aqueous electrolyte is used. [Selection diagram] Figure 1

Description

  The present invention relates to a method for manufacturing an electrode plate in a battery using a non-aqueous electrolyte and an electrode laminate. More specifically, the present invention relates to a method of manufacturing an electrode plate that is cut out from a large-sized electrode original plate and has a size that is laminated in an electrode laminate.

  Conventionally, an electrode laminate formed by laminating positive and negative electrode plates has been used as a battery component. In general, an electrode plate laminated in an electrode laminate is manufactured as a large-size electrode original plate and cut into a size suitable for lamination. As a cutting method for this purpose, one disclosed in Patent Document 1 can be cited. According to the method of this document, a solvent containing a binder resin is applied to a planned cutting position in an electrode original plate (referred to as a “band current collector” or the like in the document). And the ultraviolet rays are irradiated to the applied part. After that, cutting is to be performed. The cutting edge is softened in advance to make it easier to cut, thereby extending the life of the cutting blade.

JP2015-173081A

  However, the conventional techniques described above have the following problems. The battery performance deteriorates as much as the solvent is applied to a part of the electrode plate. This is because the properties of the electrode plate inevitably change due to the application of the solvent. The literature tries to minimize such performance degradation. Therefore, the binder resin in the solvent to be applied is the same as that used when forming the active material layer of the electrode plate. However, it cannot be denied that the amount of the binder resin is excessive as compared with the original composition. In addition, components other than the binder resin in the applied solvent must be removed. For this reason, in the technique of the literature, it is forced to insert a vacuum drying process after cutting.

  The present invention has been made to solve the above-described problems of the prior art. That is, an object of the present invention is to provide an electrode plate manufacturing method capable of obtaining an electrode plate by cutting the electrode original plate satisfactorily by a simple process without impairing battery performance.

  A method for producing an electrode plate according to an aspect of the present invention is a method for producing an electrode plate in a battery using a non-aqueous electrolyte and an electrode laminate, wherein an electrode active material layer is coated on a current collector foil. A liquid supply step for supplying a liquid to the electrode active material layer of the electrode original plate, and a portion of the electrode original plate after the liquid supply step where the liquid is supplied to the electrode active material layer by cutting and laminating it in the electrode laminate And a cutting step for forming an electrode plate. Here, the liquid supplied in the liquid supply process is of the same component as the solvent of the non-aqueous electrolyte.

  In the electrode plate manufacturing method according to the above aspect, the electrode active material layer at the planned cutting position of the electrode original plate is first wetted and softened in the liquid supply step. In this state, a cutting process is performed to cut the electrode plate. What is cut is a portion where the electrode active material layer is softened in the liquid supply step. For this reason, the electrode active material layer is not easily crushed even by the pressure at the time of cutting, so that the cutting is performed well. Thus, a good electrode plate is manufactured. Thereafter, even when the electrode plate is formed as an electrode laminate and incorporated in the battery, the properties of the nonaqueous electrolyte of the battery are not significantly changed by the liquid supplied in the liquid supply process. This is because the liquid has the same component as the solvent of the nonaqueous electrolytic solution. For this reason, the liquid supplied in the liquid supply process may remain without being removed after the cutting process.

  According to this configuration, there is provided an electrode plate manufacturing method capable of obtaining an electrode plate by satisfactorily cutting the electrode original plate by a simple process without impairing battery performance.

It is a side view which shows the structure of the apparatus which enforces the manufacturing method of the electrode plate which concerns on this form. It is a top view of the electrode original plate before a cutting | disconnection, and the electrode plate after a cutting | disconnection. It is sectional drawing which shows notionally the structure of an electrode laminated body. It is a top view which shows the solvent supply area | region in an Example. It is a top view explaining the exposure width measured in the Example.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments embodying the present invention will be described below in detail with reference to the accompanying drawings. This embodiment embodies the present invention as an electrode plate manufacturing method implemented by the apparatus shown in FIG. The apparatus of FIG. 1 is an apparatus for obtaining an electrode plate 3 by cutting the electrode plate 1 with a cutter 2. In addition to the cutter 2, the apparatus shown in FIG. 1 is provided with an entrance roller 4, a spray nozzle 5, and an exit roller 6.

  FIG. 2 shows a plan view of the electrode plate 1 and the cut electrode plate 3 cut by the apparatus shown in FIG. The electrode plate 1 is in the form of a long band extending in the left-right direction in FIG. The electrode plate 1 is generally provided in a coiled form, drawn from there, and supplied to the entry side roller 4. The electrode plate 3 is obtained by cutting the original electrode plate 1 in a direction intersecting with the longitudinal direction thereof into a card shape. The card-like electrode plate 3 is used as an electrode laminate 7 (see FIG. 3) by alternately stacking positive and negative ones. The electrode laminate 7 is built in the battery together with the non-aqueous electrolyte. Although only one positive and negative electrode plate 3 is shown in FIG. 3, the actual electrode laminate 7 has, of course, a larger number of positive and negative electrode plates 3 stacked.

  The positive electrode plate 3 in FIG. 3 is obtained by coating the front and back surfaces of the current collector foil 8 with the positive electrode active material layer 9. The negative electrode plate 3 is obtained by covering the front and back surfaces of the current collector foil 10 with a negative electrode active material layer 11 and further covering both surfaces with a separator layer 12. Instead of the negative electrode plate 3 being integrated with the separator, the positive electrode plate 3 can be integrated with the separator, and the positive and negative electrode plates 3 are not integrated with the separator, and a film separator is prepared separately. Alternatively, the separator layer may be sandwiched between the positive and negative electrode plates 3. In any case, the separator layer is a porous layer made of an insulating material such as resin.

  The apparatus of FIG. 1 will be further described. The cutter 2 is a cutter that cuts the electrode plate 1. The spray nozzle 5 supplies liquid to the electrode original plate 1. The spray nozzle 5 is configured to supply liquid to both the front and back surfaces of the electrode original plate 1. The spray nozzle 5 is arranged upstream of the cutter 2 with respect to the flow direction of the electrode plate 1. In this embodiment, as the liquid supplied from the spray nozzle 5 to the electrode original plate 1, the component used as a solvent for the above-described nonaqueous electrolytic solution (hereinafter referred to as “electrolytic solution solvent”) is used.

  A method for manufacturing the electrode plate 3 performed by the apparatus of FIG. 1 will be described. In the apparatus of FIG. 1, the electrode original plate 1 is conveyed toward the cutter 2 by the entrance side roller 4. The electrode plate 1 passes through the spray nozzle 5 before reaching the cutter 2. When the portion of the electrode plate 1 that is to be cut by the cutter 2 passes through the spray nozzle 5, the electrolyte solvent is supplied to the electrode plate 1 by the spray nozzle 5. That is, in this embodiment, the supply of the electrolyte solvent by the spray nozzle 5 is performed intermittently rather than continuously. The timing at which the spray nozzle 5 supplies the electrolytic solution solvent is controlled by the conveyance speed of the electrode plate 1 and the width dimension W (see FIG. 2) of the electrode plate 3. The width direction dimension W of the electrode plate 3 is the same as the interval W between the portions of the electrode original plate 1 that receive the supply of the electrolyte solvent.

  The portion of the electrode base plate 1 that has received the supply of the electrolyte solvent eventually reaches the cutting portion by the cutter 2. At that time, the electrode plate 1 is cut by the cutter 2. Thereby, the electrode plate 3 is cut out from the electrode original plate 1. The cut-out electrode plate 3 is carried out by a delivery roller 6.

  Here, the location where the cutter 2 is cut in the electrode plate 1 is the location where the supply of the electrolyte solvent is received by the spray nozzle 5 as described above. This has the following advantages. First, the peeling of the electrode active material layer (positive electrode active material layer 9 and negative electrode active material layer 11) from the current collector foils 8 and 10 in the vicinity of the cut portion is compared with the case where the electrolyte solvent was not supplied. And a small amount. Second, it is excellent in charge / discharge performance when assembled as a battery.

  The reason why the first advantage can be obtained is that the electrode active material layer is wetted by the electrolytic solution solvent and becomes flexible at the time of cutting. For this reason, the electrode active material layer is not crushed by the pressure from the cutter 2 at the time of cutting. Therefore, the remaining degree of the positive electrode active material layer 9 and the negative electrode active material layer 11 in the electrode plate 3 after cutting is high. This means that the effective battery reaction area in the electrode plate 3 is wide and the storage capacity of the battery is large.

  The reason why the second advantage is obtained lies in the type of components of the electrolyte solvent. The fact that the electrolyte solvent is the same component as the solvent of the non-aqueous electrolyte means that the properties of the non-aqueous electrolyte do not change much even if the electrolyte solvent is mixed into the non-aqueous electrolyte. This means that even if the electrolyte solvent remains in place after cutting, the properties of the non-aqueous electrolyte do not change much when the electrode plate 3 is incorporated into the battery. For this reason, the charge / discharge performance of the battery is not hindered by the residual electrolyte solvent for cutting.

  If a liquid different from the above is used as the liquid supplied from the spray nozzle 5, the property of the non-aqueous electrolyte may change when the liquid remains. As another type of liquid, for example, a kneading solvent used when kneading the material of the electrode active material layer can be considered. Even if it is a different kind of liquid, there is an effect of preventing the electrode active material layer from being broken at the time of cutting. However, when a different kind of liquid is mixed in the non-aqueous electrolyte, the non-aqueous electrolyte may be denatured and the charge / discharge performance of the battery may be hindered. This is not the case with this embodiment.

  Tests for confirming the effects of the present invention were conducted for the cases shown in the following examples. Each condition in this example was as follows.

Negative electrode configuration:
-Current collector foil 10: Copper foil (10 μm thick)
Negative electrode active material layer 11:
..Active material: Natural graphite particles (particle size is about 80 μm)
・ ・ Binder: Carboxymethyl cellulose, Styrene butadiene rubber ・ Separator layer 12: Porous polyethylene film (20 μm thick, acrylic binder coated on both sides)
-Electrode surface size of electrode plate 3: 112 mm x 72 mm

Positive electrode configuration:
-Current collector foil 8: Aluminum foil (10 μm thick)
-Positive electrode active material layer 9:
・ ・ Active material: Nickel-manganese-chromium ternary lithium oxide (particle size is about 70 μm) ・ ・ Binder: Polyvinylidene fluoride ・ Electrode surface size of electrode plate 3: 110 mm × 70 mm

  In other words, this was a lithium ion battery, and ethyl methyl carbonate (or dimethyl carbonate) was used as the solvent for the non-aqueous electrolyte. Then, ethyl methyl carbonate was also used as the liquid supplied from the spray nozzle 5. As shown in FIG. 4, the supply region 13 has a width of 10 mm with the planned cutting line 14 as the center. Then, as shown in FIG. 5, the maximum width of the exposed portion 15 generated on the cut pieces (upper side and lower side in FIG. 5) of the electrode plate 3 after cutting was measured.

  The results are shown in Table 1. The column of “Liquid supply amount” in Table 1 indicates the supply amount of the electrolyte solvent by the spray nozzle 5 per area of the supply region 13 in FIG. 4. The column of “time difference” indicates a time lag from when the electrolyte solvent is supplied by the spray nozzle 5 until it is cut by the cutter 2. This was adjusted by the distance between the spray nozzle 5 and the cutter 2 in FIG. The column of “exposure width” is a test result, and is a measured value of the maximum width of the exposed portion 15 shown in FIG. Table 1 shows values for the negative electrode plate 3. Although the negative electrode plate 3 is a separator-integrated type as described above, the negative electrode active material layer 11 is wetted even if the electrolyte solvent is supplied from above the separator layer 12. This is because the separator layer 12 is porous.

  In Examples 1 to 3 in Table 1, the liquid supply amount was changed while keeping the time difference constant. When these are seen, also in Example 1 with the smallest liquid supply amount, the exposure width is reduced to about 60% compared with the comparative example (no liquid supply). In Examples 2 and 3 in which the liquid supply amount was increased, the exposure width was reduced to a quarter or less in comparison with the comparative example. However, the difference between Example 2 and Example 3 is not significant.

  Examples 4 to 6 in Table 1 are obtained by changing the time difference while keeping the liquid supply amount at the same level as Example 3. In Example 4 in which the time difference was shorter than in Example 3, the effect was almost the same as in Example 1. In Examples 5 and 6 in which the time difference was made longer than in Example 3, the effect was almost the same as in Example 3. In particular, in Example 5 where the time difference was 1 second, the best result in Table 1 was obtained. From this, in the negative electrode plate 3, there is a certain effect even if the time lag from the supply of the liquid to the cutting is as short as about 0.05 seconds, but the effect is greater when the time lag is 0.5 seconds or more. I understand that. This is considered to be because a certain amount of time is required for the electrolyte solution supplied from the spray nozzle 5 to penetrate the negative electrode active material layer 11 through the separator layer 12. If the separator is not integrated, there is little need to take this time lag.

  In the configuration of the positive and negative electrodes, the solvent at the time of kneading is water or N-methyl-2-pyrrolidone. However, when these liquids are supplied from the spray nozzle 5, the electrode active material layer is formed as described above. Although it has the effect of softening, it is not good because it denatures the non-aqueous electrolyte. In particular, in the case of N-methyl-2-pyrrolidone, the acrylic binder layer on the surface of the separator layer 12 may be dissolved. In this embodiment, the use of ethyl methyl carbonate, which is a component of the nonaqueous electrolytic solution, prevents these adverse effects.

  As described in detail above, according to the present embodiment and the example, when the card-like electrode plate 3 is cut out from the long electrode original plate 1, first, the electrolyte solvent is supplied to the portion to be cut, and the supply I'm going to cut the part that I did. Thereby, while the cutting | disconnection can be performed favorably without inhibiting battery performance, the manufacturing method of the electrode plate which does not need to perform a strict drying process after cutting | disconnection is implement | achieved.

  Note that this embodiment is merely an example, and does not limit the present invention. Therefore, the present invention can naturally be improved and modified in various ways without departing from the gist thereof. For example, in the said form and Example, the aspect which obtains the card-shaped electrode plate 3 by cut | disconnecting the electrode original plate 1 in the direction perpendicular | vertical to the longitudinal direction was demonstrated. And the electrode laminated body 7 which consists of the electrode plate 3 was a flat type. However, the present invention is not limited to this, and the present invention is also applicable to an embodiment in which two long electrode plates are obtained by cutting a long electrode original plate having a width of two strips into two parallel to the longitudinal direction. Application is possible. In this case, the supply of the electrolyte solvent from the spray nozzle is performed locally and continuously. Also in this case, the obtained electrode plate after cutting is usually a wound electrode laminate.

  In addition, the type of the target battery is not limited to the lithium ion battery, but may be another type such as a nickel metal hydride battery. Further, the liquid having the same component as the solvent of the non-aqueous electrolyte does not need to completely match the solvent of the non-aqueous electrolyte. For example, when a mixture of two or more organic solvents is used as the solvent for the non-aqueous electrolyte, the electrolyte solution supplied from the spray nozzle may have a different blending ratio or two or more. Some of these organic solvents may be lacking.

DESCRIPTION OF SYMBOLS 1 Electrode base plate 2 Cutter 3 Electrode plate 5 Spray nozzle 7 Electrode laminated body 8 Current collector foil 9 Positive electrode active material layer 10 Current collector foil 11 Negative electrode active material layer 14 Planned cutting line

Claims (1)

A method for producing an electrode plate in a battery using a non-aqueous electrolyte and an electrode laminate,
A liquid supply step of supplying a liquid to the electrode active material layer of an electrode original plate obtained by coating an electrode active material layer on a current collector foil;
Cutting the electrode plate after the liquid supply step, cutting the portion where the liquid was supplied to the electrode active material layer, and making the electrode plate of a size to be stacked in the electrode laminate,
The method for producing an electrode plate, wherein the liquid supplied in the liquid supply step is of the same component as the solvent of the non-aqueous electrolyte.

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