JP2017173062A - Thickness measuring device for electrode body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To measure precise thickness of an active material layer 4 after rolling at a measurement position of an after-rolling thickness measuring instrument 15 while removing an affection caused at the active material layer 4 after rolling an electrode body 2.SOLUTION: An after-rolling guide roller 9 for carrying a rolled electrode body 2 is arranged on a downstream side of a rolling roller. The electrode body 2 is structured by intermittently coating a power collecting foil 3 with an active material layer 4. An annular protruding object 19 is attached to an outer peripheral surface 9a of the after-rolling guide roller 9. The protruding object 19 faces an after-rolling thickness measuring instrument 15. At the time of carrying the rolled electrode body 2, tension is applied to the electrode body 2 in association with winding of the electrode body 2, and thereby the electrode body 2 is locally extended below a measurement surface 15a of the after-rolling thickness measuring instrument 15 by a contact surface 20 of the protruding object 19. Therefore, precise thickness of the active material layers 4 on both sides after rolling is measured in a state where there is no wrinkle at a position for measuring thickness of the active material layer 4.SELECTED DRAWING: Figure 5

Description

  The present invention relates to an electrode body thickness measuring apparatus that measures the thickness of an active material layer applied intermittently on a current collector foil after rolling.

  Patent Document 1 discloses a rolling device for rolling a battery electrode body, and this electrode body is formed by continuously coating an active material layer on a current collector foil. This rolling apparatus includes a pre-rolling movement amount detector that detects a movement amount per unit time of an electrode body before rolling, and a post-rolling movement amount detector that detects a movement amount per unit time of the electrode body after rolling. And a thickness meter for measuring the thickness of the electrode body after rolling. In the above rolling apparatus, based on the elongation amount of the electrode body obtained from each movement amount detected by the movement amount detector before rolling and the movement amount detector after rolling, and the thickness of the electrode body after rolling measured by a thickness meter. Thus, the density of the active material layer of the electrode body is controlled.

JP 2000-188103 A

  When rolling an electrode body in which an active material layer is intermittently applied on a current collector foil using the rolling apparatus of Patent Document 1, the active material layer extends in the length direction and the width direction. On the other hand, the portion of the current collector foil where the active material layer is not coated does not extend in the width direction, so that wrinkles may occur in the active material layer.

  Here, in the rolling apparatus, the density of the active material layer is determined based on the thickness of the active material layer after rolling.

  However, if the thickness of the active material layer having wrinkles is measured with a thickness meter and this thickness is used for calculating the density of the active material layer, an accurate density cannot be calculated.

  In the present invention, an electrode body thickness measuring device for measuring the thickness of the active material layer intermittently coated on the current collector foil after rolling is provided on the downstream side of the rolling roller so as to convey the rolled electrode body. A guide roller, an annular protrusion protruding from the outer peripheral surface of the guide roller toward the outer periphery, and a thickness measuring instrument facing the annular protrusion.

  Thereby, when the electrode body passes through the annular projection on the guide roller after rolling, the wrinkles of the active material layer below the thickness measuring device are locally extended by the annular projection.

  According to the present invention, it is possible to measure the accurate thickness of the active material layer with the thickness measuring instrument in a state where there is no wrinkle at the measurement position of the thickness of the active material layer.

It is explanatory drawing of the rolling apparatus of one Example of this invention. It is a top view of the rolling apparatus of FIG. It is explanatory drawing which shows the state of the active material layer and current collection foil before and behind rolling. It is explanatory drawing which shows arrangement | positioning of the annular protrusion on a guide roller after rolling. It is explanatory drawing of the after-rolling guide roller and the after-rolling thickness measuring device seen from the rolling roller side. It is explanatory drawing of the cyclic | annular protrusion of a 2nd Example. It is explanatory drawing of the annular protrusion of a 3rd Example. It is explanatory drawing of the cyclic | annular protrusion of a 4th Example. It is sectional drawing of the annular protrusion and the after-rolling guide roller along the AA line of FIG. It is explanatory drawing of the annular protrusion of a 5th Example.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 shows a rolling device 1 having the thickness measuring device of the present invention. The rolling device 1 is used for rolling an electrode body 2 of a battery, for example, a lithium ion secondary battery. The electrode body 2 is obtained by intermittently mixing a slurry obtained by mixing an active material, a conductive additive, a binder, an organic solvent and the like with a predetermined thickness on both surfaces of a current collector foil 3 (FIG. 2), for example, an aluminum foil or a copper foil. It is formed into a band shape by coating and drying. After the slurry is dried, a plurality of active material layers 4 indicated by dots in FIG. 2 are formed on both surfaces of the current collector foil 3 at predetermined intervals.

  The rolling apparatus 1 includes a feed roll 5 that feeds the strip-shaped electrode body 2 after being wound in a roll shape, and the first and second pre-rolling guides for the electrode body 2 fed from the feed roll 5. Guide rollers 6 and 7, a pair of upper and lower rolling rollers 8 and 8 for rolling the electrode body 2, and a cylindrical or cylindrical post-rolling guide roller 9 for guiding the electrode body 2 that has passed through the rolling rollers 8 and 8. A pair of upper and lower image processing units 10 and 10 for confirming the quality of the electrode body 2 after rolling, a marking unit 11 for marking defective products of the electrode body 2 discovered by the image processing units 10 and 10, and the electrode body 2 And a winding roll 13 that winds up the electrode body 2 fed from the feed roll 5. The winding roll 13 is biaxial so that the winding of the electrode body 2 before cutting and the winding of the electrode body 2 after cutting the electrode body 2 of a predetermined length can be alternately performed. It is configured.

  In the rolling apparatus 1, when the feed roll 5 rotates clockwise in the drawing, the strip-shaped electrode body 2 has the first and second pre-rolling guide rollers 6 and 7, the rolling rollers 8 and 8, and the post-rolling guide. It is continuously supplied to the roller 9, the image processing units 10 and 10, the marking unit 11, the cutting unit 12 and the winding roll 13.

  A plurality of rollings measuring the thickness of the active material layer 4 before rolling, specifically, the thickness of the entire electrode body 2 including the active material layers 4 on both sides, on the upper left side of the second pre-rolling guide roller 7. A front thickness measuring instrument 14 is provided so as to face the second pre-rolling guide roller 7. On the other hand, above the guide roller 9 after rolling, a plurality of post-rolling thickness measurements for measuring the thickness of the active material layer 4 after rolling, specifically, the thickness of the entire electrode body 2 including the active material layers 4 on both sides. A vessel 15 is provided to face the guide roller 9 after rolling. The post-rolling thickness measuring instrument 15 is a non-contact type thickness measuring instrument, for example, a spectral interference laser displacement meter. Further, the thickness measuring device 14 before rolling and the thickness measuring device 15 after rolling determine the relatively thin thickness due to the inclination or fading of the active material layer 4 at the start of coating of the active material layer 4 and at the end of coating. The coating lengths of the front and rear active material layers 4 are measured.

  Here, for convenience of the following description, the X direction of FIG. 2 that is the length direction of the active material layer 4 is defined as “active material layer length direction”, and is a view that is the width direction of the active material layer 4. The Y direction of 2 is defined as the “active material layer width direction”.

  In this example, as shown in FIG. 2, three pre-rolling thickness measuring devices 14, 14, 14 and three post-rolling thickness measuring devices 15, 15, 15 are arranged in a predetermined direction along the active material layer width direction Y. Each is provided at intervals.

  Further, a pair of upper and lower pre-rolling width measuring instruments 16 and 16 for measuring the width of the active material layer 4 before rolling are provided between the thickness measuring instrument 14 before rolling and the pair of rolling rolls 8 and 8. It is provided on each side of the electrode body 2 along the direction Y. On the other hand, on the downstream side of the post-rolling thickness measuring instrument 15, a pair of upper and lower post-rolling width measuring instruments 17 and 17 that measure the width of the active material layer 4 after rolling are similar to the pre-rolling width measuring instruments 16 and 16, respectively. They are provided on both sides of the electrode body 2 along the active material layer width direction Y, respectively.

  In the rolling apparatus 1, the quality of the electrode body 2 is managed by calculating the density of the active material layer 4 after rolling. The density of the active material layer 4 is obtained by dividing the weight per unit area of the active material layer 4 on both sides of the current collector foil 3 (hereinafter referred to as “deposition”) by the thickness of the active material layer 4 on both sides after rolling. It is calculated by. After the electrode body 2 is rolled, in addition to the thickness of the active material layer 4 being reduced, the active material layer 4 has an active material layer length direction X and an active material layer width direction as shown exaggeratedly in FIG. It extends to both sides of Y. Therefore, when calculating the density of the active material layer 4 after rolling, first, the active material layer of the active material layer 4 is calculated from the coating length of the active material layer 4 before and after rolling measured by the thickness measuring devices 14 and 15. The elongation amount in the length direction X is obtained, and the elongation amount in the active material layer width direction Y of the active material layer 4 is obtained from the width of the active material layer 4 before and after rolling measured by the width measuring devices 16 and 17. Then, the deposition is calculated in consideration of these elongation amounts, and this deposition is divided by the thickness of the active material layer 4 measured by the thickness meter 15 after rolling.

  In addition, after the electrode body 2 is rolled, the active material layer 4 extends in both the active material layer length direction X and the active material layer width direction Y, but the current collecting foil in a portion where the active material layer 4 is not coated. Since 3 does not extend in the width direction, wavy wrinkles 18 may occur in the active material layer 4 after rolling. Furthermore, the generation | occurrence | production location of the wrinkle 18 changes with the inclination of the electrode body 2 on the coating shape of the active material layer 4, a pass line, etc. If the thickness of the active material layer 4 having the wrinkles 18 is measured, the thickness of the active material layer 4 that is uneven due to the wrinkles 18 is measured, which is a factor for calculating an inaccurate density of the active material layer 4. .

  Therefore, in the present embodiment, the thickness of the active material layer 4 after rolling is measured in a state where the influence of the wrinkles 18 generated in the active material layer 4 after rolling is eliminated.

  In this embodiment, as shown in FIG. 4, the three annular protrusions 19, 19, 19 that locally stretch the wrinkles 18 of the active material layer 4 after rolling have three post-rolling thickness measuring instruments 15, 15, It is attached to the guide roller 9 after rolling below 15 (FIG. 2). Here, the inner diameter of the annular protrusion 19 corresponds to the outer diameter of the guide roller 9 after rolling, and the protrusion 19 is attached to the outer peripheral surface (contact surface) 9a of the guide roller 9 after rolling. Moreover, you may make it the protrusion 19 fit in the cyclic | annular recessed part formed in the guide roller 9 after rolling. The protrusions 19 may be formed integrally with the guide roller 9 after rolling.

  The annular projection 19 of this embodiment is made of a material having rigidity equivalent to that of the guide roller 9 after rolling. The after-rolling guide roller 9 is made of, for example, steel or stainless steel (SUS). Accordingly, the annular protrusion 19 is made of steel or stainless steel, like the guide roller 9 after rolling.

  The annular protrusion 19 protrudes from the outer peripheral surface 9a of the guide roller 9 after rolling to the outer peripheral side. The protrusion height of the protrusion 19 is set to such a height that no transfer streaks are generated in the active material layer 4 when the electrode body 2 is conveyed in a state of being locally pressed against the protrusion 19. In one example, the protrusion height of the protrusion 19 is about several millimeters. Further, the width W of the protrusion 19 is set to be narrower than the interval between the wrinkles 18 of the active material layer 4 after rolling. In one example, the width W of the protrusion 19 is about 6 mm. Thereby, since the protrusion 19 does not contact the wrinkle 18 adjacent to the wrinkle 18 to be stretched, the sagging and the new wrinkle 18 are prevented from occurring in the active material layer 4.

  As shown in FIG. 5, the annular protrusion 19 has a contact surface 20 that comes into contact with the lower surface 2 a of the electrode body 2, and this contact surface 20 is a central position where the thickness of the active material layer 4 is measured. A flat surface 20a and arcuate surfaces 20b and 20b that are convex outward on both sides of the flat surface 20a are provided. The flat surface 20a is opposed to the measurement surface 15a of the thickness meter 15 after rolling.

  When the electrode body 2 after rolling passes through the protrusions 19 and the guide roller 9 after rolling, the tension is applied to the electrode body 2 as the winding roll 13 is wound, so that the electrode body 2 has a thickness meter after rolling. It is pressed locally against the contact surface 20 of the projection 19 below the 15 measurement surfaces 15a. Thereby, the wrinkle 18 of the active material layer 4 is locally extended in the active material layer width direction Y while following the flat surface 20a and the arcuate surfaces 20b and 20b at the measurement position of the thickness of the active material layer 4 after rolling. It is.

  In FIG. 5, the wrinkles 18 are actually generated in the active material layer 4 of the electrode body 2 that is in contact with the contact surface 9 a of the guide roller 9 after rolling. Is omitted.

  As described above, in the present embodiment, the wrinkles 18 of the active material layer 4 after rolling are locally stretched by the annular protrusions 19, so that there are no wrinkles 18 at the location where the thickness of the active material layer 4 is measured. In this state, the flat active material layer 4 is irradiated with a laser beam 21 (shown by a dotted arrow in FIG. 5) from the post-rolling thickness measuring instrument 15, so that the accurate thickness (both sides of the active material layer 4 after rolling) The total thickness of the active material layers 4) can be measured. Therefore, by dividing the deposition by the exact thickness of the active material layer 4, the density of the active material layer 4 after rolling can be accurately calculated. Thereby, management of the quality of the electrode body 2 after rolling improves.

  Further, in this embodiment, since the annular protrusion 19 has the arc surfaces 20b, 20b on both sides of the flat surface 20a, the active material layer 4 is peeled off or transferred when the electrode body 2 is rolled. Can be prevented. If the portion corresponding to the arcuate surface 20b is formed at the corner, the stress is concentrated on the corner due to the tension applied to the electrode body 2 when the electrode body 2 is wound, so that the active material layer 4 is likely to be peeled off or transferred. Therefore, by providing the circular arc surface 20b having a smooth curve, the active material layer 4 is prevented from being peeled off or transferred while the stress on the contact surface 20 is relaxed.

  FIG. 6 shows an annular protrusion 19 of the second embodiment. In this embodiment, the annular protrusion 19 is made of a material different from that of the annular protrusion 19 shown in FIGS. In the annular protrusion 19, it is desirable that the rigidity of at least the side portion 27 that applies stress to the electrode body 2, that is, the arc surface 20b, is lower than the rigidity of the contact surface 9a of the post-rolling guide roller 9 made of steel or stainless steel. More desirably, the rigidity of the arcuate surface 20b (side portion 27) is preferably equal to the rigidity of the active material layer 4.

  In the present embodiment, the annular protrusion 19 is entirely made of a material (shown by dots in FIG. 6) having the same rigidity as that of the active material layer 4. The protrusion 19 is made of an elastic body such as rubber or fluororesin.

  In the second embodiment, since the annular protrusion 19 is made of a material having rigidity equivalent to the rigidity of the active material layer 4, for example, an elastic body, the annular protrusion 19 is rolled by elastic deformation. It is possible to absorb the stress applied to the contact surface 20, particularly the arcuate surfaces 20b and 20b, when the electrode body 2 is transported later. Thereby, peeling of the active material layer 4 and transfer streaks are more reliably prevented.

  FIG. 7 shows an annular protrusion 19 of the third embodiment. In the present embodiment, the projection 19 is composed of three parts, an annular projection base 22 having a flat surface 20a similar to that shown in FIGS. 4 to 6, and arcuate surfaces 20b and 20b similar to those shown in FIGS. Are provided with two annular protrusion side portions 23 and 23 respectively.

  The protrusion base 22 is made of a material having rigidity equivalent to that of the guide roller 9 after rolling. Further, the protrusion side parts 23 and 23 are made of a material having rigidity equivalent to that of the active material layer 4. For example, it is made of rubber or fluororesin as in the above-described embodiments.

  Therefore, also according to the third embodiment, it is possible to absorb the stress applied to the arcuate surfaces 20b and 20b when the electrode body 2 after rolling is conveyed.

  FIG. 8 shows an annular protrusion 19 of the fourth embodiment. In the present embodiment, the annular protrusion 19 is composed of four parts, and an annular protrusion base 24 (shown by hatching in FIG. 9) having a smaller outer diameter than the annular protrusion base 22 of the third embodiment, The projection side portions 23 and 23 are the same as the annular projection side portions 23 and 23 of the third embodiment. Therefore, an annular groove (not shown) having the outer peripheral surface 24a of the protrusion base 24 as a bottom surface is formed between the protrusion base 24 and the protrusion side parts 23 and 23. An annular cover portion 25 having a width corresponding to the groove width is fitted into the annular groove portion. In the state in which the annular cover portion 25 is fitted, as shown in FIG. 9, the annular protrusion base 24 is attached to the outer peripheral surface 9 a of the guide roller 9 after rolling, and further, the annular protrusion base 24 is annular on the outer peripheral surface 24 a. A cover portion 25 is attached. Note that the protrusion base 24 may be formed integrally with the guide roller 9 after rolling.

  Similar to the third embodiment, the protrusion side parts 23 and 23 are made of a material having rigidity equivalent to that of the active material layer 4, such as rubber or fluororesin.

  The projection base 24 is made of a material having rigidity equivalent to that of the guide roller 9 after rolling, for example, steel or stainless steel. The annular cover portion 25 is made of a material having rigidity equivalent to that of the active material layer 4, for example, rubber or fluororesin, like the protrusion side portion 23. Accordingly, the central portion 28 of the annular protrusion 19 serving as a measurement position of the thickness of the active material layer 4 includes a protrusion base 24 having a relatively high rigidity on the inner peripheral side and a cover part having a relatively low rigidity on the outer peripheral side. 25.

  In the fourth embodiment, since the annular cover portion 25 is made of the same material as the annular protrusion side portions 23, 23, the entire contact surface 20 of the annular protrusion 19 is the same as in the second embodiment. Furthermore, it has a rigidity equivalent to that of the active material layer 4. Therefore, like the second embodiment, the annular protrusion 19 of the fourth embodiment can absorb the stress applied to the contact surface 20, particularly the arc surfaces 20 b and 20 b, when the rolled electrode body 2 is conveyed. it can.

  FIG. 10 shows an annular protrusion 19 of the fifth embodiment. In the present embodiment, the annular protrusion base 22 in the embodiment of FIG. 7 is replaced with an annular heating portion 26 having the same shape as the protrusion base 22. The annular heating unit 26 heats the electrode body 2 by generating heat with, for example, an internal heater (not shown). Here, the heating temperature by the heating unit 26 is set to be lower by about 20 to 40 ° C. than the melting point of the binder in the active material layer 4. The heating width by the heating unit 26 (the width along the active material layer width direction Y in FIG. 10) is set to be narrower than the interval between the wrinkles 18.

  In the fifth embodiment, since the electrode body 2 after rolling is heated by the heating unit 26, the binder in the active material layer 4 is softened. It becomes easy to move along the contact surface 20, particularly the flat surface 26 a of the heating unit 26. Accordingly, the wrinkles 18 of the active material layer 4 after rolling are likely to extend along the contact surface 20 of the protrusion 19.

DESCRIPTION OF SYMBOLS 1 ... Rolling apparatus 2 ... Electrode body 3 ... Current collecting foil 4 ... Active material layer 8 ... Rolling roller 9 ... Rolling guide roller 15 ... Rolling thickness measuring instrument 19 ... Projection 20 ... Contact surface 20a ... Flat surface 20b ... Arc surface 22 ... Projection base 23 ... Projection side 24 ... Projection base 25 ... Cover Part 26 .. heating part

Claims (6)

A thickness measuring device for an electrode body that measures the thickness of an active material layer applied intermittently on a current collector foil after rolling,
A guide roller provided on the downstream side of the rolling roller so as to convey the electrode body after rolling;
An annular projection projecting outward from the outer peripheral surface of the guide roller;
A thickness measuring instrument facing the annular projection;
Thickness measuring device with   The thickness measuring apparatus according to claim 1, wherein rigidity of at least a side portion of the annular protrusion is lower than rigidity of a contact surface of the guide roller.   The annular protrusion has a central annular protrusion base serving as a thickness measurement position, and annular protrusion side portions on both sides of the annular protrusion base, and the annular protrusion side portion is the annular protrusion. The thickness measuring device according to claim 1, wherein the thickness is lower than that of the base portion.   An annular projection base having a relatively high rigidity on the inner peripheral side, and an annular cover having a relatively low rigidity attached to the outer peripheral surface of the annular projection base. The thickness measuring device according to claim 1, wherein the thickness measuring device comprises: a portion.   The thickness measurement device according to claim 1, wherein the annular protrusion includes a flat surface and arc surfaces on both sides of the flat surface.   The thickness measuring device according to claim 1, wherein the annular protrusion includes a heating unit.

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