Patent Application
20130019732
The present invention relates to an electrode plate manufacturing apparatus.
Priority is claimed on Japanese Patent Application No. 2010-073169, filed on Mar. 26, 2010, the content of which is incorporated herein by reference.
Conventionally, battery cells have been used as power sources of various electrical devices. A secondary battery, which is a rechargeable battery cell, may be used as a power buffer such as a power generating device as well as the power source. As a configuration example of the battery cell, there are two types: a stacked-type in which a plurality of positive electrode plates and a plurality of negative electrode plates are stacked with separators interposed between them; and a wound-type in which one positive electrode plate and one negative electrode plate are wound with a separator interposed between them. In an electrode plate (a positive electrode plate or a negative electrode plate) of either type, a surface of a collector is coated with an electrode active material.
For example, Patent Document 1 discloses a method of manufacturing an electrode plate of a stacked-type.
In Patent Document 1, after forming an original plate by coating a surface of a sheet-like collector with an electrode active material, the original plate is die-cut using a cutting die (a Thomson die), so that a substantially rectangular electrode plate is manufactured. The cutting die is one in which a band-like cutting blade (a Thomson cutter) is vertically fixed to a support substrate, and a pressing member formed of an elastic material is attached thereto while covering the cutting blade. In a state in which the cutting die does not press the original plate, the pressing member protrudes from the support substrate above the cutting blade. That is, since the cutting blade is embedded in the pressing member, a blade edge of the cutting blade is hidden in the pressing member and thus not seen as if the cutting blade is inside the pressing member.
When the cutting die presses the original plate supported by a support, the pressing member is compression-deformed, so that the cutting blade protrudes from the support substrate above the pressing member. The original plate is pressed toward the support by a pressing force of the pressing member and cut by the cutting blade, so that the electrode plate is formed.
In Patent Document 1, in case of the cutting blade having a shape of a single-edged blade, a load is not applied to the cutting surface of the electrode plate. Therefore, a burr or a crack of an electrode active material hardly occurs.
However, even when the technique disclosed in Patent Document 1 is used, the electrode active material may be exfoliated and missed from the collector, or be separated from the collector at the corner of the electrode plate. Thus, there has been a problem in that a manufacturing yield is low.
The present invention is made in light of the above problems, and it is an object of the present invention to provide an electrode plate manufacturing apparatus in which the manufacturing yield is improved by minimizing separation of an electrode active material at the time of die-cutting an electrode plate.
In the present invention, in order to achieve the above object, the following configuration is employed.
An electrode plate manufacturing apparatus according to an aspect of the present invention includes an original plate support portion that supports an original plate of an electrode plate coated with an electrode active material, a first cutting blade that forms a linear first cutting portion in the original plate, a first support substrate, which is arranged to face the original plate support portion, having the first cutting blade fixed thereto, a second cutting blade that forms a linear second cutting portion in the original plate, a second support substrate, which is arranged to face the original plate support portion, having the second cutting blade fixed thereto, and a driving portion that drives the first and second support substrates, wherein when the first support substrate is driven by the driving portion, the first cutting portion is formed by the first cutting blade, and when the second support substrate is driven by the driving portion, on the original plate in which the first cutting portion is formed, the second cutting portion is formed by the second cutting blade to intersect with the first cutting portion.
In this electrode plate manufacturing apparatus, the first cutting blade forms the first cutting portion, and the second cutting blade forms the second cutting portion on the original plate in which the first cutting portion is formed. A portion in which the first cutting portion intersects with the second cutting portion becomes a portion that configures a corner of an electrode plate to be die-cut. As described above, two sides that configure the corner of the electrode plate are cut at different timings.
Thus, unlike the case in which two sides connected to the corner are cut at the same time, since the original plate is prevented from being compressed from the two sides at the same time, separation of the electrode active material is reduced and prevented.
According to the electrode plate manufacturing apparatus, an electrode active material can be prevented from being separated in the corner of an electrode plate, and thus a manufacturing yield can be improved.
Hereinafter, exemplary embodiments of the present invention will be described with reference to the drawings. In the drawings used for description, in order to illustrate characteristic portions in an easily understood manner, a dimension or a scale of components in the drawing may be different from that of actual components. A combination of all components described in embodiments is not necessarily indispensable to the present invention. In embodiments, the same reference numerals are given to the same components, and a detailed description thereof may be omitted. Before describing an electrode plate manufacturing apparatus according to the present invention, a configuration example of a battery cell will be described.
As illustrated in
The battery case 10 of the present example is a hollow container made of aluminum and has a substantially prism-like (a substantially rectangular parallelepiped) shape. The battery case 10 includes a case body 11 having an opening and a cover 12 bonded to the case body 11 to close the opening.
Electrode terminals 13 and 14 are disposed on the cover 12. The electrode terminal 13 is a positive terminal, and the electrode terminal 14 is a negative terminal. A plurality of electrode plates 15 and 16 and a plurality of separators 17 are housed inside the battery case 10. The electrode plate 15 is a positive electrode plate, and the electrode plate 16 is a negative electrode plate. The plurality of electrode plates 15 and 16 are repetitively arranged such that the positive electrode plate and the negative electrode plate are alternately lined up. An electrode active material of the electrode plate 15 which is a positive electrode plate is, for example, a ternary-system material (LiNixCoyMnzO2 (x+y+z=1)), and an electrode active material of the electrode plate 16 which is a negative electrode plate is, for example, a carbon material (e.g., artificial graphite).
The separator 17 is arranged to be sandwiched between a pair of electrode plates 15 and 16 and prevents the electrode plates 15 and 16 from coming in direct contact with each other. The separator 17 is made of a porous insulating material or the like and allows an electrolytic component such as lithium ions to pass therethrough. In fact, a stacked body is formed by stacking a plurality of positive electrode plates, a plurality of negative electrode plates, and a plurality of separators. The battery cell 1 has a structure in which the stacked body is housed in the battery case 10. The electrolyte is retained to come in contact with the electrode plates 15 and 16 inside the battery case 10.
As illustrated in
A direction in which the electrode tab 151 protrudes is substantially orthogonal to the short side 155 and parallel to a main surface of the electrode body part 150. The electrode tab 151 is formed to lean to one side of the short side 155. The electrode tabs 151 of the plurality of electrode plates 15 are collectively electrically connected to the electrode terminal 13.
As illustrated in
The electrode plate 15 includes the electrode body part 150 which is coated with the electrode active material 157 and the electrode tab 151 which is not coated with the electrode active material 157. The electrode tab 151 is formed by die-cutting the collector 152 as will be described later.
The electrode plate 16 differs in the formation material of the electrode active material as described above. Although the dimension of the electrode body part is formed to be larger than that of the electrode plate 15, the structure and shape of the electrode body part is same that of the electrode plate 15. As illustrated in
Next, an electrode plate manufacturing apparatus according to a first embodiment will be described. The electrode plate manufacturing apparatus according to the present invention can be used for manufacturing any of a positive electrode plate and a negative electrode plate, but here an example in which it is applied to the electrode plate 15, which is a positive electrode plate, will be described.
As illustrated in
The first cutting die 4 includes a first support substrate 40, and a set of first cutting blades 41 and a set of second cutting blades 42 which are fixed to the first support substrate 40. The two cutting blades are at the same position in a Y direction which is a conveying direction, and aligned and arranged not to overlap each other in an X direction. Specifically, the two cutting blades are disposed at the positions to be line-symmetric to an imaginary line extending from the center of a formation area 92 in the X direction to the Y direction, which is the conveying direction.
The second cutting die 5 includes a second support substrate 50, a set of third cutting blades 51 which are fixed to the second support substrate 50 and correspond to the first cutting blades 41, and a set of fourth cutting blades 52 which are fixed to the second support substrate 50 and correspond to the second cutting blades. The two cutting blades are at the same position in the Y direction, and aligned and arranged at the positions respectively corresponding to the cutting blades of the first cutting die 4 in the X direction. Specifically, the two cutting blades are disposed at the positions to be line-symmetric to an imaginary line extending from the center of the formation area 92 in the X direction to the Y direction, which is the conveying direction.
A combination of the shape of the first cutting blade 41 and the shape of the third cutting blade 51 corresponding thereto becomes the shape of the electrode plate. Similarly, a combination of the shape of the second cutting blade 42 and the shape of the fourth blade 52 corresponding thereto becomes the shape of the electrode plate. That is, the two electrode plates 15 having the same shape can be formed at the same time by the first cutting die 4 and the second cutting die 5.
The first to fourth cutting blades are configured with, for example, a Thomson cutter.
As described later, a first pressing portion 43 covering the periphery of the first and second cutting blades is disposed on the first cutting die 4, and a second pressing portion 53 covering the periphery of the third and fourth cutting blades is disposed on the second cutting die 5.
The driving system 3 is configured with conveying rollers 21 to 24 as a conveying, a control portion 30, a driving portion 31, and holding portions 32 and 33.
The components of the electrode plate manufacturing apparatus 2 are arranged as follows.
The conveying rollers 21 and 22 are disposed to sandwich the original plate support portion 20 in the Y direction so as to convey a protection sheet 90 along a planar upper surface 20a of the original plate support portion 20. The conveying rollers 23 and 24 are disposed to sandwich the original plate support portion 20 and the conveying rollers 21 and 22 in the Y direction so as to convey an original plate 91 arranged on the protection sheet 90 on the upper surface 20a in the Y direction similarly to the protection sheet 90. Here, the Y direction is a direction in which the conveying rollers 21 to 24 convey the original plate 91 or the die-cut electrode plate.
As illustrated in
For example, the protection sheet 90 is made of a resin sheet. When the cutting blade penetrates and cuts the original plate 91, the protection sheet 90 prevents the cutting blades from touching the upper surface 20a of the original plate support portion 20, that is, the cutting blades from getting damaged.
The driving portion 31 is disposed above (+Z direction) the original plate support portion 20. Support posts 34 to 37 in which one ends thereof are arranged on the same plane and which perform up-down movement by the driving portion 31 are connected to the driving portion 31. The holding portion 32 is connected to the other ends of the support posts 34 and 35, and the holding portion 33 is connected to the other ends of the support posts 36 and 37.
The first cutting die 4 is attached to a lower surface side of the holding portion 32, and the second cutting die 5 is attached to a lower surface side of the holding portion 33.
Here, the holding portion 32 and the holding portion 33 are described as separate configurations, the holding portion 32 and the holding portion 33 may be combined as one holding portion.
A schematic operation of the electrode plate manufacturing apparatus 2 is as follows.
The control portion 30 controls an operation of the conveying rollers 21 to 24 and the driving portion 31. First, the control portion 30 conveys the original plate 91 and the protection sheet 90, which are synchronized with each other, by a predetermined interval and then stops the conveying rollers 21 to 24. That is, the control portion 30 controls the conveying rollers 21 to 24 which intermittently perform an operation.
The predetermined interval refers to a distance from a midpoint between the set of first cutting blades 41 in the Y direction and a midpoint between the set of third cutting blades 51 in the Y direction.
After the conveying rollers 21 to 24 stop, the control portion 30 controls the driving portion 31 such that the holding portions 32 and 33 moves downward (−Z direction). Thus, the first cutting die 4 and the second cutting die 5 move toward the upper surface 20a of the original plate support portion 20 and press the original plate 91 conveyed onto the upper surface 20a. The first to fourth cutting blades 41, 42, 51, and 52 cut the original plate 91, and thus a first cutting portion by the first cutting die 4 and a second cutting portion by the second cutting die 5 are formed in the original plate 91.
At this time, die cutting of the electrode plate 15 is completed when the second cutting portion is formed.
After the first cutting portion and the second cutting portion are formed, the holding portions 32 and 33 move upward (+Z direction), and thus the first cutting die 4 and the second cutting die 5 retreat from the original plate 91, that is, withdraw upward. After the withdrawal, the control portion 30 controls the conveying rollers 21 to 24 such that the original plate 91 and the protection sheet 90 are conveyed the predetermined distance, and thus the conveying rollers 21 to 24 stop.
After the stopping, the control portion 30 controls the driving portion 31 such that the first cutting die 4 and the second cutting die 5 move toward the upper surface 20a of the original plate support portion 20 again. As a result of the conveyance, the first cutting portion is positioned directly below the second cutting die. Thus, by re-movement of the original plate support portion 20, the first cutting portion and the second cutting portion are joined together, and portions surrounded by the first cutting portion and the second cutting portion are die-cut from the original plate 91 as the two electrode plates 15.
The electrode plate manufacturing apparatus 2 repeats the above operation and repetitively die cuts the original plate 91.
As illustrated in
An electrode tab of one electrode plate is die-cut from the non-formation area 93 at one end of the original plate 91, and an electrode tab of another electrode plate is die-cut from the non-formation area 93 at the other end. That is, as described above, the third cutting blade 51 and the fourth cutting blade 52 are arranged so that a total of two electrode plates with the electrode tabs can be simultaneously die cut.
As illustrated in
The second cutting blade 42 also has the same configuration.
The third cutting blade 51 includes a third blade element 54 and a fourth blade element 55. The third blade element 54 refers to a portion that forms the short side 154. The fourth blade element 55 refers to a portion that forms the short side 155 and the electrode tab 151. Similarly to
The fourth cutting blade 52 also has the same configuration.
The first to fourth blade elements 44, 45, 54, and 55 are independent of one another, and are all configured with a single-edged band-like body. For example, the plate thickness of the band-like body ranges from about 0.5 mm to 2.0 mm. On the band-like body, a blade edge is disposed along one side in the width direction. The band-like body is attached to the first support substrate 40 and the second support substrate 50 so that the width direction can be substantially vertical to the facing surface.
The first pressing portion 43 and the second pressing portion 53 are members that press the original plate 91 toward the original plate support portion 20 when the original plate 91 is die-cut. For example, the first pressing portion 43 and the second pressing portion 53 are configured of an elastic body such as rubber or sponge.
In the first pressing portion 43, a dimension (thickness) of the facing surface 40a in a normal direction is set so that a surface 43a can protrude toward the original plate support portion 20 further than a blade edge 443. As the pressing portion, any member capable of pressing the original plate 91 toward the original plate support portion 20 can be used. For example, a member having a pressing surface may be biased toward the original plate support portion 20 by a spring or the like. Further, the pressing portion may be supported by another member different from the support member of the first and second cutting blades. This is similarly applied to the second pressing portion 53.
The first cutting blade 41 and the third cutting blade 51 are arranged to satisfy the following condition. Here, the first blade element 44 imaginarily parallel-shifted in the conveying direction (Y direction) by a predetermined distance ΔY is referred to as a first imaginary blade element 44a. Similarly, the second blade element 45 imaginarily parallel-shifted in the conveying direction by a predetermined distance AY is referred to as a second imaginary blade element 45a. That is, in a state in which the facing surface of the second support substrate 50 is viewed in a plan view, the first imaginary blade element 44a intersects with the third and fourth blade elements 54 and 55, and the second imaginary blade element 45a intersects with the third and fourth blade elements 54 and 55.
The first imaginary blade element 44a and the second imaginary blade element 45a may intersect so as to overlap the end portion of the third blade element 54 and the end portion of the fourth blade element 55 portion or may intersect with the third blade element 54 and the fourth blade element 55 at an inner side of the end portion. Here, both of the first imaginary blade element 44a and the second imaginary blade element 45a intersect with the third blade element 54 and the fourth blade element 55.
A portion surrounded by the first imaginary blade element 44a, the second imaginary blade element 45a, the third blade element 54, and the fourth blade element 55 has an electrode plate shape P. The original plate is die-cut in the electrode plate shape P, and thus the electrode plate 15 of
Thus, an outline of the electrode plate 15 illustrated in
The first extension portion P1 extends from the first corner portion P6 in a first direction (the X direction), and the second extension portion P4 extends in a second direction (the Y direction) to intersect with the first extension portion P1 at the first corner portion P6.
The first extension portion P1 extends from the second corner portion P7 in the first direction, and the second extension portion P3 extends in the second direction to intersect with the first extension portion P1 at the second corner portion P7.
The first extension portion P2 extends from the third corner portion P8 in the first direction, and the second extension portion P3 extends in the second direction to intersect with the first extension portion P2 at the third corner portion P8.
The first extension portion P2 extends from the fourth corner portion P9 in the first direction, and the second extension portion P4 extends in the second direction to intersect with the first extension portion P2 at the fourth corner portion P9.
In the die-cutting process, when the conveying rollers 21 to 24 stop, first, the first cutting die 4 presses the original plate 91. Thus, the second cutting die 5 presses the original plate 91 together with the first cutting die 4. As illustrated in
As illustrated in
Then, when the first cutting die 4 further moves downward, as illustrated in
Then, when the first cutting die 4 further moves downward, as illustrated in
Next, the original plate 91 in which the first cutting portion 94n has been formed is conveyed downstream in the conveying direction (the Y direction) by a predetermined distance ΔY (see
Next, the first cutting die 4 and the second cutting die 5 press the original plate 91 again. A new first cutting portion 94n+1 is formed in the original plate 91 below the first cutting die 4. Further, a second cutting portion 95 which has a second pattern corresponding to the second cutting blade 51 is formed in the original plate below the second cutting die 5. The second cutting portion 95 is formed to intersect with the first cutting portion 94n, and a portion surrounded by the first cutting portion 94n and the second cutting portion 95 is die-cut from the original plate 91 as the electrode plate 15.
Next, the original plate 91 is conveyed downstream in the conveying direction (the Y direction) by a predetermined distance ΔY (see
The die-cut electrode plate 15 is separated from the original plate 91 by a separation means (not shown) after the first cutting die 4 and the second cutting die 5 move away from the original plate 91. After the separation, a void portion 96 is formed in the original plate.
Meanwhile, as illustrated in
In the electrode plate manufacturing apparatus disclosed in Patent Document 1, the original plate is almost simultaneously cut all around the cutting blade, and a portion, which becomes a corner of the electrode plate (also referred to as a “corner portion”), almost simultaneously receives a compression force from two sides connected to the corner portion. When the compression force is above a certain value, since the collector and the electrode active material differ in material and in mechanical characteristics from each other, the collector and the electrode active material are not deformed at the same time. In this case, a shear force acts in a direction parallel to an interface between the collector and the electrode active material (hereinafter referred to simply as an “interface”), and thus adhesion between the collector and the electrode active material is lowered.
In the electrode plate die-cutting apparatus 2 according to the first embodiment, the first pattern by the first cutting die 4 and the second pattern by the second cutting die 5 are formed at different timings, and a portion in which the first pattern and the second pattern intersect with each other becomes the corner portion of the electrode plate 15. Thus, a maximum value of a compression force acting on the corner portion of the electrode plate 15 at a time is lowered, and adhesion between the collector 911 and the electrode active materials 912 and 913 at the corner portion of the electrode plate 15 is prevented from being lowered. Thus, during or after die-cutting, the electrode active material is not easily separated from the collector at the corner portion of the electrode plate 15.
Since the first cutting blade 41 and the third cutting blade 51 are arranged so that the first pattern can intersect with the second pattern, even if positional deviation has occurred in the original plate 91, a problem in which the first pattern is not connected with the second pattern is prevented. Further, both end portions of the first cutting blade 41 in the extending direction are positioned outside the portion which becomes the electrode plate 15, and the both end portions of the third cutting blade 51 in the extending direction are positioned outside the portion which becomes the electrode plate 15. Thus, even if portions cut by both ends portions of the first cutting blade 41 and the second cutting blade 51 have been distorted, this distortion does not have a bad influence on the electrode plate 15.
This point is similarly applied to a relation between the second cutting blade 42 and the fourth cutting blade 52.
The first cutting blade 41 and the third cutting blade 51 are configured with a single-edged blade in which an edge blade leans to the surface side which forms the contour of the electrode plate shape P. Thus, a portion surrounded by the first pattern and the second pattern, that is, a portion which becomes the electrode plate 15, is smaller in displacement of the cutting surface than the outside of the portion. As a result, a compression force acting on the portion which becomes the electrode plate 15 is reduced, and separation of the electrode active material in the electrode plate 15 is reduced.
As described above, according to the electrode plate manufacturing apparatus 2 according to the first embodiment, separation of the electrode active material can be reduced. Thus, it is possible to prevent battery performance from being lowered due to a reduction in the amount of electrode active material of the electrode plate portion, and a high-performance battery cell can be configured. Further, exposure of the collector caused by peeling of the electrode active material is prevented, and a short circuit caused by exposure of the collector is avoided. Thus, a battery cell in which few problems occur can be formed.
Further, a technical scope of the present invention is not limited to the above embodiment. Various modifications can be made in a range not departing from the gist of the present invention. For example, modifications which will be described below are conceivable.
The electrode body portion 150B has a substantially octagonal shape in which corners of a rectangle are removed when seen in a plan view, and all inner angles are obtuse angles.
Specifically, the electrode body portion 150B includes sides 152B to 159B. The sides 152B and 153B extend in a first direction (the Y direction). The sides 154B and 155B extend in a second direction (the X direction) substantially orthogonal to the first direction. The side 156B is connected to the side 155B and the side 152B near a base end of the electrode tab 151. The side 157B is connected to the side 152B and the side 154B. The side 158B is connected to the side 153B and the side 154B. The side 159B is connected to the side 153B and the side 155B.
As illustrated in
If the first cutting blade 41B is imaginarily parallel-shifted in the conveying direction by a predetermined distance to overlap the second cutting blade 51B, a first imaginary cutting blade and the second cutting blade 51B are joined, so that blade edges are distributed along the electrode plate shape Q. The electrode plate manufacturing apparatus according to the first modified embodiment is the same in configuration of portions except for the first cutting die 4B and the second cutting die 5B as in the first embodiment.
According to the electrode plate manufacturing apparatus according to the first modified embodiment, since the inner angles of the corner portions of the electrode body portion 150B are obtuse angles, the die-cut electrode plate 15B does not have separation of the electrode active material occurring at the corner portion. The electrode plate 15B may be die-cut by an electrode plate manufacturing apparatus according to a second modified embodiment, which will be described next.
In the second cutting die 5C, a third cutting blade 51C is disposed to correspond to the sides 152B and 153B in the electrode plate shape Q. In the third cutting die 5D, a fourth cutting blade 51D is disposed to correspond to the sides 154B and 155B and the outer periphery of the electrode tab 151 in the electrode plate shape Q.
If the second cutting blade 51 C is imaginarily parallel-shifted in the conveying direction by a predetermined distance, and the first cutting blade 41B is imaginarily parallel-shifted in the conveying direction by two times a predetermined distance, they are joined, so that blade edges are distributed along the electrode plate shape Q.
The present invention is not limited to the three cutting dies and the patterns of the cutting blades illustrated in
Further, the outer periphery of the electrode tab and the side 155B in the electrode plate shape Q configure a connected cutting blade. However, in order to prevent separation of the electrode active material of corresponding portions and manufacture the electrode plate with a higher degree of accuracy, the outer periphery of the electrode tab and the side 155B may configure cutting blades respectively corresponding to separate cutting dies.
In the third modified embodiment, a first cutting die 4E is configured such that a first blade element 44 and a second blade element 45 that constitute a first cutting blade and a first pressing portion 43E are disposed on a facing surface of a first support substrate 40. A notch 46E is disposed in a portion along the one surface 441 at a side of the first blade element 44 facing the second blade element 45. Since the notch 46E is disposed, this one surface 441 is apart from the first pressing portion 43E. In the present example, the other surface 442, which is a back surface of the one surface 441, comes in contact with the first pressing portion 43E. The notch 47E is disposed in a portion along one surface at a side of the second blade element 45 facing the first blade element 44. This one surface is apart from the first pressing portion 43E.
A second cutting die 5E is configured such that third and fourth blade elements 54 and 55 that constitute a second cutting blade and a second pressing portion 53E are disposed on one surface of a second support substrate 40. A notch 56E is disposed in a portion along one surface at a side of the third blade element 54 facing the fourth blade element 55. This one surface is apart from the second pressing portion 53E. The notch 57E is disposed in a portion along one surface at a side of the fourth blade element 55 facing the third blade element 54. This one surface is apart from the second pressing portion 53E.
When the electrode plate 15 is die-cut from the original plate 91 by the electrode plate manufacturing apparatus including the first cutting die 4E and the second cutting die 5E configured in the above described manner, as will be described later, an effect of reducing separation of the electrode active material can increase. Here, while the above description has been made in connection with the vicinity of the cutting portion by the first blade element 44, the present embodiment is similarly applied to the vicinities of the cutting portions by the second to fourth blade elements 45, 54, and 55.
As illustrated in
In the end portion 94b, as the position of a portion coming in contact with the first pressing portion 43E is restricted, a range deformable in a direction parallel to the main surface of the original plate 91 is confined. Since distortion of the end portion 94b is difficult to mitigate, the compression force F4 intensively acts on the end portion 94b. Since the deformable range is confined, the end portion 94b is not easily deformed by bending. Thus, the compression force F4 acts on in a direction substantially parallel to the interface, and most of the compression force F4 contributes to generating a shear force which causes deviation of the collector 911 and the electrode active materials 912 and 913. However, since the end portion 94b is a portion that does not become the electrode plate, even if the electrode active material exfoliated from the end portion 94b, few problems occur.
In the original plate 91, an end portion 94c including a cutting portion at a side coming in contact with the one surface 441 is a portion which becomes the electrode plate. The end portion 94c receives a compression force F3 reverse to the compression force F4 from the one surface 441 and compressed in the normal direction of the one surface 441. As the notch 46E is disposed, the end portion 94c includes a portion, which is not pressed against the first pressing portion 43E, between a portion pressed against the first pressing portion 43E and a portion coming in contact with one surface 441. Since the end portion 94c has a deformable range wider than the end portion 94b, the end portion 94c is small in compression stress acting thereon and is easily deformed by bending. As bending deformation (an angle of deflection) of the end portion 94c increases, a tangential line L of the interface at which the end portion 94c comes in contact with the one surface 441 is more inclined with respect to a normal direction of the one surface 441.
The compression force F3 may be split into a component force F5 parallel to the tangential line L and a component force F6 vertical to the tangential line L. The component force F5 is a force which deviates the current collecting material 911 and the electrode active materials 912 and 913 similarly to the shear force. The component force F6 is a force which causes the collector 911 and the electrode active materials 912 and 913 to approach each other in a portion coming in contact with the one surface 441. That is, the component force F6 acts to cause the collector 911 and the electrode active materials 912 and 913 to adhere to each other.
As the inclination of the tangential line L to the direction parallel to the main surface of the original plate 91 increases, the ratio of the component force F6 to the component force F5 increases. That is, as the inclination of the tangential line L increases, the shear force that exfoliates the current collecting material 911 and the electrode active materials 912 and 913 decreases, and a force that causes the electrode active material 912 and 913 to adhere to the current collecting material 911 increases. That is, by making the inclination of the tangential line L equal to or larger than a predetermined value, an effect of increasing an adhesion force by the component force F6 can be more excellent than an effect of reducing an adhesion force by the component force F5.
In the third modified embodiment, an interval between the one surface 441 and the first pressing portion 43E, that is, a dimension of the notch 46E is set to allow the end portion 94c to be bent so that an adhesion force can be secured to the extent that the current collecting material 911 and the electrode active materials 912 and 913 are not exfoliated.
On the dimension of the notch, an interval between the pressing portion and the cutting blade is preferably set to 1 mm or more, and when the interval is set to 2 mm or more, an effect of reducing exfoliation of the electrode active material may increase. In the process of die cutting, from a point of view for reducing positional deviation between the original plate and the cutting blade, the interval is preferably 10 mm or less, and when the interval is 5 mm or less, an effect of reducing positional deviation may increase. As described above, the interval is preferably 1 mm or more and 10 mm or less, and more preferably, 2 mm or more and 5 mm or less.
The electrode plate manufacturing apparatus according to the third modified embodiment not only can prevent separation of the electrode active material at the corner of the electrode plate but also can prevent separation of the electrode active material when the original plate is cut through the straight line-like cutting blades.
In the cutting die 4F having the above described structure, unlike the configuration in which the first cutting blade 41 and the second cutting blade 51 are disposed on the different support substrates, respectively, clearance between a plurality of support substrates need not be secured, and thus the first and second cutting blades 41 and 42 can be arranged to be close to the third and four cutting blades 51 and 52. Thus, the device size can be reduced.
As illustrated in
The mark forming portion 46 is disposed in a first cutting die 4G. The mark forming portion 46 is disposed to come in contact with the non-formation area 93 of the original plate 91 when the first cutting die 4G presses the original plate 91. The mark forming portion 46 comes in contact with the original plate 91 and forms a through hole at the contact position as the alignment mark. Thus, the alignment mark is formed at the position associated with the position of the first cutting portion 94n and 94n+1 illustrated in
The mark detecting portion 25 is disposed on the original plate support portion 20. The mark detecting portion 25 includes a photo-sensitive element therein. The mark detecting portion 25 detects the position of the through hole by detecting light passing through the through hole formed by the mark forming portion 46. Since the mark detecting portion 25 is arranged near the original plate 91, the position of the through hole can be detected with a high degree of accuracy.
The mark detecting portion 25 is electrically connected to the control portion 30 and outputs a detection result to the control portion 30. The control portion 30 controls the conveying rollers 21 to 24 based on the detection result of the mark detecting portion 25 so that the first cutting portion can be conveyed up to a predetermined position. Thus, the relative position of the first cutting portion to the second cutting blades 51 and 52 can be controlled with a high degree of accuracy, and the electrode plate 15 of a highly accurate shape can be die-cut.
Further, as the mark forming portion, for example, one in which a coating material is attached to the original plate 91 at the position associated with the position of the first cutting portion may be used. Instead of the mark forming portion 46, alignment marks may be formed on the original plate 91, for example, at regular intervals in advance. In this case, the first cutting blade can come in contact with the original plate at the position associated with the position of the alignment mark based on a result of detecting the alignment mark. As a result, since the contact position between the original plate and the first cutting blade is already known, the contact position between the original plate and the first cutting blade is detected. When it is difficult to detect the alignment mark through the original plate 91, the mark detecting portion 25 is preferably disposed above the original plate support portion 20.
Next, a description will be made in connection with an electrode plate manufacturing apparatus according to a second embodiment. The second embodiment is different from the first embodiment in that a cylindrical cutting die is provided instead of the flat plate-like cutting die.
As illustrated in
The control portion 80 controls rotation of the conveying rollers 21 to 24 such that the original plate 91 and the protection sheet 90 are displaced in the conveying direction at a predetermined displacement speed. The driving portion 81 is controlled by the control portion 80 and rotates the first rotating body 83 and the second rotating body 84 at the same circumferential speed as the displacement speed.
Thus, the first rotating body 83 and the second rotating body 84 rotate while coming in contact with the original plate 91 without slipping.
The first rotating body 83 is one in which first cutting blades 85a and 85b are disposed on the outer circumferential surface of a cylindrical support portion. The first rotating body 83 is supported to be rotatable on a central axis C1. The central axis C1 is parallel to the upper surface 20a of the original plate support portion 20 and orthogonal to the conveying direction. Here, two sets of first cutting blades 85a and 85b are disposed at the positions to be line-symmetric to an imaginary line extending from the center of the formation area 92 of the original plate 91 in the X direction to the Y direction which is the conveying direction. The first rotating body 83 is arranged so that the first cutting blades 85a and 85b can come in contact with the original plate 91 supported on the upper surface 20a with the rotation of the first rotating body 83.
The second rotating body 84 is one in which second cutting blades 86a and 86b are disposed on the outer circumferential surface of a cylindrical support portion. The diameter of the support portion of the second rotating body 84 is the same as that of the first rotating body 83. Thus, the circumferential speeds of the first rotating body 83 and the second rotating body 84 can easily become uniform. The second rotating body 84 is supported to be rotatable on a central axis C2 substantially parallel to the central axis C1. Here, two sets of second cutting blades 86a and 86b are disposed at the positions to be line-symmetric to an imaginary line extending from the center of the formation area 92 of the original plate 91 in the X direction to the Y direction which is the conveying direction. The second rotating body 84 is arranged so that the second cutting blades 86a and 86b can come in contact with the original plate 91 supported on the upper surface 20a with the rotation of the second rotating body 84.
As illustrated in
The first cutting blades 85a and 85b extend in an axial direction of the support portion. In
Unlike the first embodiment in which an intermittent operation is performed, the first rotating body 83, the second rotating body 84, and the conveying rollers 21 to 24 rotate without stopping in the process of die-cutting the electrode plate. As illustrated in
The original plate 91 is conveyed with the rotation of the first rotating body 83 and the second rotating body 84, and at a time t1, the first cutting portion 97a comes in contact with the second rotating body 84. When the first cutting portion 97a is closest to the second rotating body 84, the second rotating body 84 comes in contact with the original plate 91 near the reference line L2.
Next, the second cutting blades 86a and 86b cut the original plate 91, so that second cutting portions 98a and 98b are formed, and the original plate 91 is conveyed. The second cutting portions 98a and 98b correspond to parts of the short sides 154 and 155 and part of the electrode tab 151 of the electrode plate 15. At a time t2, the first cutting blade 85b comes in contact with the original plate 91, so that a first cutting portion 97b is formed. The first cutting portion 97b corresponds to the long side 153 of the electrode plate 15. Then, at a time t3, the first cutting blade 85a comes in contact with the original plate 91, so that a first cutting portion 97c is formed. The first cutting portion 97c is a portion of the long side 152 of the electrode plate which is to be die-cut next.
At a time t4, die-cutting of the electrode plate is completed. In the above described manner, the electrode plate is continuously die-cut.
In the electrode plate manufacturing apparatus 7 according to the second embodiment, since the first cutting portion and the second cutting portion corresponding to the two sides connected to the corner portion of the electrode plate 15 are formed at different timings, the electrode active material does not easily separated from the collector at the corner portion of the electrode plate 15.
The first cutting blades 85a and 85b and the second cutting blades 86a and 86b are disposed along the outer circumferential surface of the cylindrical support portion, and thus the apparatus size can be reduced in the direction parallel to the surface of the original plate 91 compared to the planar cutting die. Further, since the original plate 91 can be die-cut during the conveyance, efficiency of die-cutting the original plate 91 can be improved as much as the conveyance does not stop.
The exemplary embodiments of the present invention have been described above, but the present invention is not limited to the above embodiments. Addition, omission, replacement, and other alternation can be made in a range not departing from the gist of the present invention. The present invention is not limited to the above description and confined only by the accompanying claims.
According to the electrode plate manufacturing apparatus, separation of the electrode active material can be minimized when the electrode plate is die-cut, and thus the manufacturing yield can be improved.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2010-073169 | Mar 2010 | JP | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/JP2011/056858 | 3/22/2011 | WO | 00 | 9/21/2012 |
