JP2009176650A - Electrode plate for nonaqueous secondary battery, nonaqueous secondary battery using the same, and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a nonaqueous secondary battery which can prevent exfoliation of an electrode mix layer of a cut portion of an electrode plate, can avoid thermal runaway due to internal short-circuit, and is excellent in safety, by restricting an insertion angle of the electrode plate into cutting blades and an exit port angle after cutting thereof when the electrode plate is cut by a gang blade. <P>SOLUTION: An inflection angle θ1 a positive electrode plate 8 and a cutting lower blade 12 make and an inflection angle θ2 the positive electrode plate 8 and a cutting upper blade 11 make are made not less than 175°, thereby suppressing bending of the electrode plate in cutting. An exit port angle θ3 and an exit port angle θ4 are made not less than 10°, thereby preventing contact of cutting portions of a positive electrode plate 9 and a positive electrode plate 10 after cutting and preventing exfoliation of the electrode mix layer. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  TECHNICAL FIELD The present invention relates to an electrode plate for a non-aqueous secondary battery represented by a lithium ion battery, a non-aqueous secondary battery using the same, a manufacturing method thereof, and a manufacturing apparatus, and more particularly to a non-aqueous secondary battery with improved safety. Is.

In recent years, lithium secondary batteries, which are widely used as power sources for portable electronic devices, use a carbonaceous material capable of occluding and releasing lithium for the negative electrode plate, and a transition metal such as LiCoO ₂ and lithium for the positive electrode plate. A composite oxide is used as an active material, and this has realized a non-aqueous secondary battery with a high potential and a high discharge capacity. However, with the recent multi-functionalization of electronic and communication devices, the capacity has increased. Is desired. In these lithium secondary batteries, while increasing capacity, safety measures should be emphasized, and in particular, it is extremely important to suppress a rapid temperature rise due to an internal short circuit between the positive electrode plate and the negative electrode plate. .

  Conventionally, as one of the problems, there is a problem that when the positive electrode plate and the negative electrode plate are cut into predetermined dimensions, the active material is dropped from the current collector and the current collector is exposed. In a non-aqueous secondary battery in which an electrode group in which an electrode plate and a separator are wound is inserted into a battery case and sealed after injecting an electrolyte, the current collector of the positive electrode plate is particularly exposed during charging and discharging. An internal short circuit when the part and the active material of the negative electrode plate come into contact causes thermal runaway.

  Various proposals have been made as means for suppressing the peeling of the current collector and the active material to the above-mentioned problem. For example, when cutting using a gang blade, it is attached to the upper shaft 62 as shown in FIG. It has been proposed to prevent the active material from falling off at the cut portion of the electrode plate by changing the clearance 64 between the end faces of the lower blade 61 attached to the upper blade 60 and the lower shaft 63 from 20 μm to 60 μm (for example, Patent Document 1).

Further, for example, when cutting using a gang blade as shown in FIG. 9, the circumferential edge portion of the side surface 72 of the upper blade 70 is tapered 74 and the circumferential edge portion of the side surface 73 of the lower blade 71 is tapered. It has been proposed to prevent the active material from dropping off at the cut portion of the electrode plate by applying the processing 75 (see, for example, Patent Document 2).
JP-A-2005-317496 JP 2006-172828 A

  However, the electrode plate for a non-aqueous secondary battery is made up of a three-layer part in which an active material is applied on both sides of an aluminum current collector or a copper current collector and an uncoated part in which no active material is applied. Therefore, it is very difficult to cut the three-layer portion and the uncoated portion with the same cutting blade. In the conventional technique for preventing the active material from falling off in the above-mentioned Patent Document 1, even if the active material can be prevented from falling off, burrs are generated when the current collector in the uncoated part is cut to induce an internal short circuit. Had problems. Moreover, in the prior art which prevents the active material from falling off in Patent Document 2, there is a problem that the dropping of the active material depends on the adhesion strength of the active material and the current collector, the thickness of the electrode plate, or the strength of the electrode plate. Had.

The present invention has been made in view of the above-described conventional problems. When cutting an electrode plate, the active material of the cutting portion is regulated by regulating the insertion angle of the electrode plate into the cutting blade and the exit angle after cutting the electrode plate. It is an electrode plate for a non-aqueous secondary battery that can prevent detachment of the battery, and an object thereof is to provide a non-aqueous secondary battery excellent in safety that can avoid thermal runaway due to an internal short circuit.

  In order to solve the above conventional problems, the electrode plate for a non-aqueous secondary battery according to the present invention is a positive electrode mixture in which an active material, a conductive material and a binder comprising at least a lithium-containing composite oxide are kneaded and dispersed in a dispersion medium. A coating material is applied onto the positive electrode current collector and dried to form a positive electrode mixture layer and pressed to a predetermined thickness, or at least an active material and a binder made of a material capable of holding lithium in a dispersion medium. A non-aqueous secondary battery comprising a negative electrode plate coated with a kneaded and dispersed negative electrode coating material, dried to form a negative electrode mixture layer, and pressed to a predetermined thickness and cut to a predetermined size. The length of peeling from the cut surface of the positive electrode mixture layer of the positive electrode current collector or the negative electrode mixture layer of the negative electrode current collector in the longitudinal direction of the positive electrode plate or negative electrode plate Less than or equal to the thickness of the positive electrode mixture layer or negative electrode mixture layer It is characterized in.

  According to the electrode plate for a non-aqueous secondary battery of the present invention, the active material can be prevented from peeling off at the cut portion of the positive electrode plate or the negative electrode plate, and thermal runaway due to an internal short circuit can be avoided. In addition, when the electrode plate after cutting is continuously wound, it is possible to avoid cutting of the electrode plate at the cutting portion, and the yield in the manufacturing process can be improved.

  In the first invention of the present invention, a positive electrode mixture paint obtained by kneading and dispersing at least an active material composed of a lithium-containing composite oxide, a conductive material, and a binder in a dispersion medium is applied onto a positive electrode current collector and dried. A negative electrode current collector is formed by forming a positive electrode mixture layer and pressing it to a predetermined thickness, or a negative electrode mixture paint obtained by kneading and dispersing an active material and a binder made of a material capable of holding at least lithium in a dispersion medium An electrode plate for a non-aqueous secondary battery, which is formed by cutting a negative electrode plate that has been applied and dried to form a negative electrode mixture layer and pressed to a predetermined thickness, and is cut to a predetermined size, and is a positive electrode plate or a negative electrode plate The length of the positive electrode current collector in the longitudinal direction of the positive electrode mixture layer from the cut surface of the positive electrode mixture layer or the length of the negative electrode current collector from the cut surface of the negative electrode mixture layer is the thickness of the positive electrode mixture layer or the negative electrode mixture layer. Due to the following, thermal runaway due to internal short circuit It is possible to avoid, and it is possible to ensure the safety of the non-aqueous secondary battery, and it is possible to avoid the electrode plate breakage of the cut part when continuously winding the electrode after cutting, and the yield in the manufacturing process can be avoided. It can be improved.

  In the second invention of the present invention, a positive electrode mixture paint obtained by kneading and dispersing at least an active material comprising a lithium-containing composite oxide, a conductive material, and a binder in a dispersion medium is applied onto the positive electrode current collector and dried. A positive electrode plate pressed to a predetermined thickness after forming a positive electrode mixture layer or a negative electrode mixture coating material in which an active material made of a material capable of holding at least lithium and a binder are kneaded and dispersed in a dispersion medium A non-aqueous system in which a negative electrode plate that is applied to a body and dried to form a negative electrode mixture layer and then pressed to a predetermined thickness is cut into predetermined dimensions, and then the positive electrode plate or the negative electrode plate is divided and wound up alternately after being cut. A method for manufacturing an electrode plate for a secondary battery, wherein when the electrode plate is cut with an upper and lower cutting blade, the bending angle is changed from 175 ° to 180 ° when the electrode plate is cut, and the electrode plates are adjacent after being cut. Cutting By separating the subsequent electrode plates in an up-and-down direction, the cutting portion is not affected by the influence of the active material and current collector adhesion strength, the electrode plate thickness, or the electrode plate strength depending on the dropout of the active material. The active material can be prevented from falling off, and thermal runaway due to an internal short circuit can be avoided.

  In the third invention of the present invention, when the electrode plate is cut by the upper and lower cutting blades, a horizontal roll is provided to be inserted in the center and horizontally of the upper and lower cutting blades at the inlet portion, and the adjacent cut electrodes at the outlet portion. By installing the outlet rolls that separate the plates alternately in the upper and lower directions at 10 ° or more, it is possible to prevent the active material in the cut portion from falling off and to avoid thermal runaway due to an internal short circuit.

  According to a fourth aspect of the present invention, in a non-aqueous secondary battery in which an electrode group consisting of a positive electrode plate, a negative electrode plate, a separator laminate or a wound body is enclosed in a case together with a non-aqueous electrolyte, By using the electrode plate according to claim 1 as the negative electrode plate, thermal runaway due to an internal short circuit can be avoided.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. For example, as shown in FIG. 4, in the non-aqueous secondary battery of the present invention, a separator 18 includes a positive electrode plate 16 using a composite lithium oxide as an active material and a negative electrode plate 17 using a material capable of holding lithium as an active material. After the electrode group 22 wound in a spiral shape is manufactured through the electrode, the electrode group 22 is housed in the bottomed cylindrical battery case 19 together with the insulating plate 25 and is led out from the lower part of the electrode group 22. 24 is connected to the bottom of the battery case 19, and then the positive electrode lead 23 led out from the upper part of the electrode group 22 is connected to the sealing plate 20. The battery case 19 has an electrolyte solution (not shown) made of a predetermined amount of nonaqueous solvent. Then, a sealing plate 20 having a sealing gasket 21 attached to the periphery is inserted into the opening of the battery case 19, and the opening of the battery case 19 is bent inward to seal it.

  Further, the electrode group 22 for the non-aqueous secondary battery includes, for example, a positive electrode plate 3 and a negative electrode current collector 4 in which positive electrode mixture layers 2a and 2b are formed on both surfaces of the positive electrode current collector 1 as shown in FIG. It consists of a negative electrode plate 6 and a separator 7 on which negative electrode mixture layers 5a and 5b are formed. For example, as shown in FIG. 3A, the uncut positive plate 8 is inserted into the cutting upper blade 11 and the cutting lower blade 12 via the horizontal roll 15, and the cutting upper blade 11 and the cutting lower blade 12 After cutting, the positive electrode plate 9 and the positive electrode plate 10 are wound into a hoop shape via an outlet roll 13 and an outlet roll 14 installed at the outlet angle θ3 and the outlet angle θ4.

  When the positive electrode plate 8 is inserted horizontally with respect to the cutting upper blade 11 and the cutting lower blade 12, the bending angle θ1 of the positive electrode plate 8 and the cutting lower blade 12 and the bending angle θ2 of the positive electrode plate 8 and the cutting upper blade 11 are respectively set. By setting the angle to 175 ° or more, bending of the electrode plate during cutting can be suppressed, and by setting the exit angle θ3 and the exit angle θ4 to 10 ° or more respectively, the cut portions of the positive electrode plate 9 and the positive electrode plate 10 after cutting It becomes possible to prevent mutual contact. At this time, for example, as shown in FIGS. 1 (a) and 1 (b), the negative electrode composite is formed on both surfaces of the positive electrode plate 3 and the negative electrode current collector 4 formed with the positive electrode mixture layers 2 a and 2 b on both surfaces of the positive electrode current collector 1. In the negative electrode plate 6 on which the agent layers 5a and 5b are formed, peeling of the positive electrode current collector 1 and the positive electrode mixture layers 2a and 2b and peeling of the negative electrode current collector 4 and the negative electrode mixture layers 5a and 5b can be suppressed. As shown in 3 (a), the refraction strength of the electrode mixture layer and the current collector is maintained by preventing the contact angle between the cut portions after cutting and that the refraction angle of the electrode plate at the time of cutting is large. This is considered to be the reason why peeling of the electrode mixture layer can be suppressed.

  For example, as shown in FIG. 3B, the uncut positive plate 8 is inserted into the cutting upper blade 11 and the cutting lower blade 12 via the horizontal roll 15, and the cutting upper blade 11 and the cutting lower blade 12 After cutting, the positive electrode plate 9 and the positive electrode plate 10 are wound in a hoop shape via the outlet roll 13 and the outlet roll 14 installed at the outlet angle θ5 and the outlet angle θ6. When the positive electrode plate 8 is inserted in the horizontal direction, the bending angle θ1 of the positive electrode plate 8 and the lower cutting blade 12 and the bending angle θ2 of the positive electrode plate 8 and the upper cutting blade 11 are set to 175 ° or more, respectively. Although bending of the plate can be suppressed, the cut portions of the positive electrode plate 9 and the positive electrode plate 10 after cutting are brought into contact with each other by setting the outlet angle θ5 and the outlet angle θ6 to be less than 10 °.

At this time, for example, as shown in FIGS. 5 (a) and 5 (b), the negative electrode composite is formed on both surfaces of the positive electrode plate 3 and the negative electrode current collector 4 having the positive electrode mixture layers 2 a and 2 b formed on both surfaces of the positive electrode current collector 1. In the negative electrode plate 6 on which the agent layers 5a and 5b are formed, peeling of the positive electrode current collector 1 and the positive electrode mixture layers 2a and 2b and peeling of the negative electrode current collector 4 and the negative electrode mixture layers 5a and 5b are likely to occur. As shown in FIG. 3 (b), the electrode plate has a reduced refraction angle between the electrode mixture layer and the current collector due to the small refraction angle of the electrode plate at the time of cutting and the contact between the cut portions after cutting. This is considered to be the reason why the mixture layer is easily peeled off.

  For example, as shown in FIG. 3C, the uncut positive electrode plate 8 is inserted from the lower (or higher) direction than the meshing height of the upper cutting blade 11 and the lower cutting blade 12, and the upper cutting blade 11 and the lower cutting edge are cut. The positive electrode plate 9 and the positive electrode plate 10 after being cut by the blade 12 are wound into a hoop shape via an outlet roll 13 and an outlet roll 14 installed at the outlet angle θ3 and the outlet angle θ4.

  When the positive electrode plate 8 is inserted from below (or above) the height of engagement between the upper cutting blade 11 and the lower cutting blade 12, the uncut positive electrode plate 8 is tangential to the lower cutting blade 12, and therefore bent. The angle θ7 is 180 °, and the positive electrode plate 9 after cutting does not peel off the active material. However, as shown in FIG. The reason why the peel strength of the current collector is maintained is considered to be the reason why peeling of the electrode mixture layer can be suppressed.

  On the other hand, when the positive electrode plate 8 is cut by the cut upper blade 11, the uncut positive electrode plate 8 has a bending angle θ8 of less than 170 ° with respect to the cut upper blade 11, and the positive electrode plate 9 after cutting is peeled off of the active material. However, as shown in FIG. 3 (c), the electrode mixture layer peels off because the peel strength between the electrode mixture layer and the current collector decreases due to the contact between the cut parts after cutting. It is thought that it is easy to do.

  Next, for example, FIGS. 6A, 6 </ b> B, 6 </ b> C, 6 </ b> D, and 6 </ b> E show that the upper cutting blade 26 and the lower cutting blade 27 have positive electrode mixture layers on both surfaces of the positive electrode current collector 28. The process of cutting while entering the positive electrode plate 30 on which 29a and 29b are formed is shown. FIG. 6 is a cross-sectional view of the electrode plate showing the cutting process of the electrode plate. FIG. 6A shows a state before the cutting upper blade 26 and the cutting lower blade 27 enter the positive electrode plate 30, and there is no change in the positive electrode current collector 28 and the positive electrode mixture layers 29a and 29b. FIG. 6B shows an initial state in which the upper cutting blade 26 and the lower cutting blade 27 have entered the positive electrode plate 30, and the positive electrode current collector 28 and the positive electrode mixture layers 29 a and 29 b of the positive electrode plate 30 are deformed by shearing. It is in the state which started.

  FIG. 6C shows a state in which the upper cutting blade 26 and the lower cutting blade 27 are closer to each other so that the positive electrode plate 33 and the positive electrode plate 36 are separated. The positive electrode plate 33 is separated from the current collector 31 and the positive electrode mixture layer. The state after cutting | disconnection which consists of 32a and the positive mix layer 32b is shown, and the positive electrode plate 36 shows the state after cutting | disconnection which consists of the electrical power collector 34, the positive mix layer 35a, and the positive mix layer 35b. At this stage, the positive electrode plate 33 and the positive electrode plate 36 are separated into two positive plates, but the cut surface of the positive electrode plate 33 and the cut surface of the positive electrode plate 36 are in contact with each other.

  FIG. 6D shows a state of the positive electrode plate 33 and the positive electrode plate 36 when the apexes of the upper cutting blade 26 and the lower cutting blade 27 are engaged with each other. The positive electrode plate 33 is the current collector 31 and the positive electrode mixture layer 32a. The positive electrode plate 36 shows a state after cutting consisting of the current collector 34, the positive electrode mixture layer 35a, and the positive electrode mixture layer 35b. The cut surface 33 and the cut surface of the positive electrode plate 36 are completely separated. FIG. 6E shows the state of the positive electrode plate 33 and the positive electrode plate 36 when passing through the upper cutting blade 26 and the lower cutting blade 27, and this stage is similar to that of FIG. The cut surface and the cut surface of the positive electrode plate 36 are completely separated.

  For example, FIG. 7 shows an electrode plate cutting device, but an electrode plate 38 unwound from an electrode plate roll 37 passes through a horizontal roll 39 and then is cut by upper cutting blades 40a, 40b, 40c and lower cutting blades 41a, 41b. It is cut into a predetermined cutting size and a predetermined number of rows. The cutting dimension and the number of rows can be switched by the number of cutting upper blades and cutting lower blades attached. The cut electrode plates 38 are separated in a staggered manner like an electrode plate 47a and an electrode plate 46a, an electrode plate 46a and an electrode plate 47b, an electrode plate 47b and an electrode plate 46b, and an electrode plate 46b and an electrode plate 47c.

  At this time, the electrode plates 46a and 46b are wound up via the upper traveling outlet roll 42 and the guide roll 44, but the upper traveling outlet roll 42 has the electrode plates 46a and 46b at an angle of 10 ° or more with respect to the horizontal. On the other hand, the electrode plates 47a, 47b and 47c are wound up via the lower traveling outlet roll 43 and the guide roll 45, but the lower traveling outlet roll 43 has the electrode plates 46a and 46b horizontally It is installed at an angle of 10 ° or less. As described above, it is necessary to maintain the peel strength between the electrode mixture layer and the current collector by increasing the refraction angle of the electrode plate at the time of cutting and preventing contact between the cut portions after cutting. It is thought that peeling of the agent layer can be suppressed.

  Next, a method for producing the positive electrode plate 3 and the negative electrode plate 6 will be specifically described. First, the positive electrode plate 3 is not particularly limited, but a sintered metal body made of aluminum, an aluminum alloy, nickel, or a nickel alloy can be used. The thickness is 10 μm to 40 μm, the porosity is 20% to 60%, A positive electrode mixture paint in which a positive electrode active material, a conductive material, and a binder are mixed and dispersed in a dispersion medium such as a planetary mixer on one or both sides of a positive electrode current collector 1 having a pore diameter of 1 μm to 5 μm. Is applied, dried and rolled to form a positive electrode mixture layer.

  Examples of the positive electrode active material include lithium cobaltate and modified products thereof (such as lithium cobaltate in which aluminum or magnesium is dissolved), lithium nickelate and modified products thereof (such as nickel partially substituted with cobalt). And composite oxides such as lithium manganate and modified products thereof.

  As the conductive material at this time, for example, carbon black such as acetylene black, ketjen black, channel black, furnace black, lamp black and thermal black, and various graphites may be used alone or in combination.

  As the binder for the positive electrode at this time, for example, polyvinylidene fluoride (PVdF), a modified polyvinylidene fluoride, polytetrafluoroethylene (PTFE), a rubber particle binder having an acrylate unit, and the like can be used. At this time, an acrylate monomer or an acrylate oligomer into which a reactive functional group is introduced can be mixed in the binder.

  On the other hand, the negative electrode plate 6 is not particularly limited, but a sintered metal body made of copper or a copper alloy can be used. The thickness is 10 μm or more and 40 μm or less, the porosity is 20% or more and 60% or less, and the pore diameter is 1 μm or more. A negative electrode active material, a binder, and optionally a conductive material and a thickener were mixed and dispersed in a dispersion medium such as a planetary mixer on one or both sides of the negative electrode current collector 4 having a thickness of 5 μm or less. The negative electrode mixture layer is formed by applying, drying and rolling a negative electrode mixture paint.

  As the negative electrode active material, various natural graphites, artificial graphite, silicon-based composite materials such as silicide, and various alloy composition materials can be used.

  Various binders such as PVdF and modified products thereof can be used as the negative electrode binder at this time. From the viewpoint of improving lithium ion acceptability, styrene-butadiene copolymer rubber particles (SBR) and modified products thereof are used. Etc. can also be used.

  Next, the separator is not particularly limited as long as it has a composition that can withstand the use range of the lithium ion secondary battery, but a microporous film of an olefin resin such as polyethylene or polypropylene is generally used singly or in combination. And preferred as an embodiment. The thickness of the separator is not particularly limited, but may be 10 to 25 μm.

Moreover, for the electrolytic solution, it is possible to use various lithium compounds such as LiPF ₆ and LiBF ₄ as an electrolyte salt. Further, ethylene carbonate (EC), dimethyl carbonate (DMC), diethyl carbonate (DEC), and methyl ethyl carbonate (MEC) can be used alone or in combination as a solvent.

  It is also preferable to use vinylene carbonate (VC), cyclohexylbenzene (CHB), or a modified product thereof in order to form a good film on the positive and negative electrode plates or to ensure stability during overcharge. Hereinafter, specific embodiments of the present invention will be described in more detail with reference to the drawings.

  The result of having evaluated the relationship between peeling of the positive electrode mixture layer, internal short circuit, and winding deviation of the electrode group is shown. The evaluation method is to produce a wound electrode group using an electrode group manufacturing apparatus (not shown), evaluate the occurrence frequency of internal short circuit using a short circuit inspection machine (not shown), and X-ray inspection machine Was used to evaluate the winding deviation between the positive electrode plate and the negative electrode plate.

  As a criterion for evaluating the internal short circuit, a voltage of 200 volts was applied to the electrode group, and when the voltage drop amount was smaller than the set reference value, a non-defective product was designated. In addition, as the evaluation criteria of the X-ray inspection machine, the position of the negative electrode plate wider than the positive electrode plate was used as a reference, and if the positive electrode plate was within the width of the negative electrode plate, it was judged as a non-defective product. The number of inspections was 100. In Example 1, a positive electrode plate in which the length B of peeling of the positive electrode mixture layer was smaller than the thickness A of the positive electrode mixture layer was used.

(Comparative Example 1)
The same evaluation method as in Example 1 was used, and Comparative Example 1 was obtained using a positive electrode plate in which the length B of peeling of the positive electrode mixture layer was larger than the thickness A of the positive electrode mixture layer.

  In the result of Example 1, there was no occurrence of an internal short circuit failure and 1% of winding failure occurred, whereas in Comparative Example 1, 15% of internal short circuit failure and 8% of winding failure occurred. From the above results, it can be seen that if the length of peeling of the positive electrode mixture layer is equal to or less than the thickness of the mixture layer, an internal short circuit can be prevented and winding deviation can be suppressed. Further, it is considered that the internal short-circuit failure and the winding deviation failure tend to increase as the mixture peeling length increases, so an approach to reduce the length of the electrode mixture layer peeling is required.

  First, by changing the bending angle θ1 at the cutting blade inlet, the electrode mixture layer peels off the electrode mixture layer in the positive electrode plate 20 after cutting, the electrode mixture layer falls off, and the electrode mixture layer falls off during the group electrode group configuration. The evaluation results are shown. As shown in FIG. 3A, the evaluation apparatus uses an apparatus that cuts the positive electrode plate 19 with a cutting upper blade 22 and a cutting lower blade 23, and the evaluation positive electrode plate 20 has a length of 200 mm. did. The positive electrode plate of Example 1 was cut by setting the bending angle θ1 of the cutting blade inlet of the positive electrode plate 19 to 175 °.

Using the same cutting method as in Example 2, the bending angle θ1 at the cutting blade inlet of the positive electrode plate 19 was set to 180 ° as Example 3.

(Comparative Example 2)
The same cutting method as in Example 2 was used, and Comparative Example 2 was obtained by setting the bending angle θ1 of the cutting blade inlet of the positive electrode plate 19 to 170 °.

  In the result of Example 2, when the bending angle θ1 of the cutting blade inlet of the positive electrode plate 19 was 175 °, peeling of the electrode mixture layer occurred in two places, but the electrode mixture layer did not fall off after cutting, There was no loss of the electrode mixture layer after the electrode group configuration. Moreover, in the result of Example 3, when the bending angle θ1 of the cutting blade inlet was set to 180 °, the electrode mixture layer was peeled off at one place, but the electrode mixture layer was not dropped after cutting, and the electrode group There was no dropout of the electrode mixture layer after construction.

  On the other hand, when the bending angle θ1 at the cutting blade entrance is set to 170 °, the electrode mixture layer is peeled off at 47 locations, and the electrode mixture layer is dropped after cutting and the electrode mixture layer is dropped after the electrode group is configured. It was. It can be seen that when the electrode mixture layer is peeled off many times, the electrode mixture layer falls off after cutting and after the electrode group structure. As a cause of the dropping of the electrode mixture layer shown in Comparative Example 2, the positive electrode plate 19 travels along the cutting lower blade 23 after cutting, but the positive electrode plate 19 is bent at the moment when it is separated by the cutting lower blade 23. It is considered that the electrode mixture layer falls off when the bending angle θ1 is large.

  From the above results, it can be said that the bending angles θ1 and θ2 at the entrance of the cutting blade of the positive electrode plate 19 are 175 ° or more as a good countermeasure against the electrode mixture layer falling off.

  Next, by changing the exit angle θ3 of the positive electrode plate 20 after cutting, the electrode mixture layer peels off the electrode mixture layer from the positive electrode plate 20 after cutting, the electrode mixture layer falls off, and the electrode mixture layer during electrode group configuration The result of evaluation of omission is shown.

  As shown in FIG. 3A, the evaluation apparatus uses an apparatus that cuts the positive electrode plate 19 with a cutting upper blade 22 and a cutting lower blade 23, and the evaluation positive electrode plate 20 has a length of 200 mm. did. From the results of Example 1, the bending angle θ1 at the cutting blade inlet of the positive electrode plate 19 was set to 175 °. Example 4 in which the bending angle θ3 at the cutting blade entrance of the positive electrode plate 19 was set to 10 ° was used.

  Using the same cutting method as in Example 4, the outlet angle θ3 of the positive electrode plate 20 after cutting was set to 15 ° as Example 5.

(Comparative Example 3)
Using the same cutting method as in Example 4, the outlet angle θ3 of the positive electrode plate 20 after cutting was set to 5 ° as Comparative Example 3.

  In the result of Example 4, when the exit angle θ3 of the positive electrode plate 20 after cutting was 10 °, peeling of the electrode mixture layer occurred in three places, but the electrode mixture layer did not drop after cutting, and the electrode There was no loss of the electrode mixture layer after the group configuration. Further, in the result of Example 5, when the bending angle θ3 of the cutting blade inlet was set to 15 °, the electrode mixture layer was peeled off at three places, but the electrode mixture layer was not dropped after cutting, and the electrode group There was no dropout of the electrode mixture layer after construction.

  On the other hand, when the bending angle θ3 at the cutting blade entrance is 5 °, the electrode mixture layer is peeled off at 21 locations, and the electrode mixture layer is dropped after cutting and the electrode mixture layer is dropped after the electrode group is configured. It was. It can be seen that when the electrode mixture layer is peeled off many times, the electrode mixture layer falls off after cutting and after the electrode group structure.

  The cause of the drop of the electrode mixture layer shown in Comparative Example 3 is that the cut portions of the positive electrode plate 20 and the positive electrode plate 21 after cutting the outlet angle θ3 are in contact with each other, and the cutting is performed when the outlet angle θ3 is small. It is considered that the electrode mixture layer falls off because the parts easily come into contact with each other.

  From the above results, it can be said that 10 ° or more of the exit angles θ3 and θ4 of the positive electrode plate 20 after cutting is good as a measure against dropping of the electrode mixture layer. From the results of this experiment, it is preferable to restrict both the bending angle of the cutting blade inlet and the outlet angle after cutting in order to suppress the electrode mixture layer from falling off.

  The electrode plate for a non-aqueous secondary battery according to the present invention comprises a positive electrode mixture paint obtained by kneading and dispersing at least an active material comprising a lithium-containing composite oxide, a conductive material, and a binder in a dispersion medium. A positive electrode plate formed by forming a positive electrode mixture layer and drying to a predetermined thickness, or a negative electrode mixture paint prepared by kneading and dispersing an active material and a binder composed of a material capable of holding at least lithium in a dispersion medium An electrode plate for a non-aqueous secondary battery comprising a negative electrode plate formed on a negative electrode current collector, dried to form a negative electrode mixture layer and pressed to a predetermined thickness, and cut to a predetermined dimension. The length of the peeling from the cut surface of the positive electrode mixture layer from the positive electrode current collector in the longitudinal direction of the plate or the negative electrode plate or the length of the peeling from the cut surface of the negative electrode mixture layer from the negative electrode current collector By making it below the thickness of the negative electrode mixture layer, Can avoid thermal runaway due to fault, it is excellent for use in safety with the multi-functionality of electronic devices and communication devices useful as a portable power source such as a high capacity is desired.

(A) Sectional drawing which shows the positive electrode plate without peeling of the mixture layer which concerns on one embodiment in this invention, (b) Sectional drawing which shows the negative electrode plate without peeling of the mixture layer The schematic diagram which shows the cross section of the electrode group which concerns on one embodiment in this invention (A) Schematic diagram showing a method for cutting an electrode plate in the present invention, (b) Schematic diagram showing a method for cutting the electrode plate, (c) A method for cutting an electrode plate according to another embodiment of the present invention Schematic diagram showing 1 is a partially cutaway perspective view of a cylindrical secondary battery according to an embodiment of the present invention. (A) Cross-sectional view showing positive electrode plate with peeling of mixture layer in conventional example, (b) Cross-sectional view showing negative electrode plate with peeling of mixture layer (A) A sectional view of the electrode plate showing the cutting process of the electrode plate in the present invention, (b) a sectional view of the electrode plate showing the cutting process of the electrode plate, (c) an electrode plate showing the cutting process of the electrode plate Cross-sectional view, (d) Cross-sectional view of electrode plate showing cutting process of same electrode plate, (e) Cross-sectional view of electrode plate showing cutting process of same electrode plate The schematic diagram which shows the electrode plate cutting device which concerns on one embodiment in this invention. Schematic diagram showing a conventional electrode plate cutting device Schematic diagram showing a cutting device in a conventional example

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Positive electrode collector 2a, 2b Positive electrode mixture layer 3 Positive electrode plate 4 Negative electrode collector 5a, 5b Negative electrode mixture layer 6 Negative electrode plate 7 Separator 8 Positive electrode plate 9 Positive electrode plate 10 Positive electrode plate 11 Cutting upper blade 12 Cutting lower blade 13 Exit roll 14 Exit roll 15 Horizontal roll 16 Positive electrode plate 17 Negative electrode plate 18 Separator 19 Battery case 20 Sealing plate 21 Sealing gasket 22 Electrode group 23 Positive electrode lead 24 Negative electrode lead 25 Insulating plate 26 Cutting upper blade 27 Cutting lower blade 28 Positive electrode current collector 29a, 29b Positive electrode mixture layer 30 Positive electrode plate 31 Current collector 32a, 32b Positive electrode mixture layer 33 Positive electrode plate 34 Current collector 35a, 35b Positive electrode mixture layer 36 Positive electrode plate 37 Electrode plate roll 38 Electrode plate 39 Horizontal roll 40a, 40b, 40c Cutting upper blade 41a, 41b Cutting lower blade 42 Upper traveling outlet roll 43 Lower traveling outlet roll 44 Idororu 45 guide roll 46a, peeling length of 46b electrode plates 47a, 47b, the thickness of 47c electrode plate A positive electrode mixture layer B positive electrode mixture layer

Claims (4)

  A positive electrode mixture paint obtained by kneading and dispersing at least an active material composed of a lithium-containing composite oxide, a conductive material, and a binder in a dispersion medium is applied onto a positive electrode current collector and dried to form a positive electrode mixture layer. A negative electrode mixture, in which an active material made of a material capable of holding at least lithium and a binder capable of holding lithium and a binder mixed and dispersed in a dispersion medium is applied onto the negative electrode current collector and dried. A non-aqueous secondary battery electrode plate comprising a layer formed and pressed to a predetermined thickness and cut to a predetermined size, wherein the positive electrode plate or the positive electrode current collector in the longitudinal direction of the negative electrode plate The length of the peeling from the cut surface of the positive electrode mixture layer or the peeling from the cut surface of the negative electrode mixture layer of the negative electrode current collector is equal to or less than the thickness of the positive electrode mixture layer or the negative electrode mixture layer. Non-aqueous secondary battery electrode plate.   After forming a positive electrode mixture layer by applying and drying a positive electrode mixture coating material obtained by kneading and dispersing at least an active material composed of a lithium-containing composite oxide, a conductive material, and a binder in a dispersion medium. A negative electrode coating material obtained by kneading and dispersing a positive electrode plate pressed to a predetermined thickness or an active material made of a material capable of holding at least lithium and a binder in a dispersion medium is dried on the negative electrode collector. A method for producing an electrode plate for a non-aqueous secondary battery in which a negative electrode plate pressed to a predetermined thickness after forming an agent layer is cut into a predetermined size, and the positive electrode plate or the negative electrode plate is cut and wound alternately after being cut. When the electrode plate is cut with an upper and lower cutting blade, the bending angle is set to 175 ° to 180 ° when the electrode plate is cut, and the adjacent cut electrode plates are moved up and down after the electrode plate is cut. Mutual A method for producing an electrode plate for a non-aqueous secondary battery, characterized in that the electrode plates are separated in different ways.   An apparatus for manufacturing an electrode plate for a non-aqueous secondary battery comprising an electrode plate unwinding section, a cutting section, and a winding section, wherein a horizontal roll that is inserted into the center of the upper and lower cutting blades is installed at the inlet section, and the outlet section Then, the upper traveling exit roll that separates the electrode plates after cutting alternately in the vertical direction is installed at 10 ° or more with respect to the horizontal, and the lower traveling exit roll is installed at 10 ° or less with respect to the horizontal. An apparatus for manufacturing an electrode plate for an aqueous secondary battery.   2. The electrode according to claim 1, wherein the positive electrode plate and the negative electrode plate are used in a non-aqueous secondary battery in which a group of electrodes including a positive electrode plate, a negative electrode plate, a laminated body or a wound body of a separator is enclosed in a case together with a non-aqueous electrolyte. A non-aqueous secondary battery using a plate.

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