Battery Case Shaping Apparatus and Battery Case Manufacturing Method Using the Same

Abstract

A battery case shaping apparatus includes a punch, a die, a holder, and an elastic separator. The punch is configured to press a laminate sheet into a shape of an electrode assembly receiving portion. The die has formed therein an accommodation portion having a size corresponding to the electrode assembly receiving portion. The holder is configured to fix the an outer periphery of the laminate sheet. The elastic separator is located under the punch in order to prevent direct contact between the punch and the laminate sheet. A battery case manufacturing process uses the battery case shaping apparatus to manufacture a battery case.

Claims

1. AA battery case shaping apparatus comprising: a punch configured to press a laminate sheet into a shape of an electrode assembly receiving portion; a die in which an accommodation portion is formed, the accommodation portion having a size corresponding to the electrode assembly receiving portion; a holder configured to fix an outer periphery of the laminate sheet; and an elastic separator located under the punch in order to prevent direct contact between the punch and the laminate sheet.

2. The battery case shaping apparatus according to claim 1, wherein the elastic separator is fixed to the holder.

3. The battery case shaping apparatus according to claim 2, wherein the elastic separator is fixed to a lower part of a side surface of the holder.

4. The battery case shaping apparatus according to claim 1, wherein a lower surface of the punch is configured to be parallel to an upper surface of the elastic separator before the electrode assembly receiving portion is shaped by the punch.

5. The battery case shaping apparatus according to claim 2, further comprising a liquid lubricant received in a space formed by the elastic separator and the holder.

6. The battery case shaping apparatus according to claim 1, further comprising a recess is-formed in at least a portion of a lower surface of the punch.

7. The battery case shaping apparatus according to claim 1, further comprising a pad is disposed in and at a lower part of the accommodation portion of the die.

8. The battery case shaping apparatus according to claim 7, wherein the pad is made of an elastic material and includes a central part that convexly protrudes.

9. The battery case shaping apparatus according to claim 8, wherein the central part of the pad is configured to contract as a result of pressing by the punch, whereby a thickness of the pad becomes uniform over an entirety of the pad in a punching direction parallel to the direction of the pressing of the punch.

10. The battery case shaping apparatus according to claim 1, wherein the elastic separator is watertight.

11. A battery case shaping method using the battery case shaping apparatus according to claims 1, the battery case shaping method comprising: (a) disposing the laminate sheet on the die; (b) fixing the laminate sheet to the die using the holder having the elastic separator attached to the holder; and (c) pressing the elastic separator and thereby shaping the laminate sheet using the punch.

12. The battery case shaping method according to claim 11, further comprising adding a liquid lubricant into a space formed by the elastic separator and the holder between step (b) and step (c).

13. The battery case shaping method according to claim 11, wherein, in step (c), the pressing is performed until a pad disposed in a lower part of the accommodation portion of the die is compressed and flat.

14. The battery case shaping method according to claim 13, wherein, when compression of the pad starts, liquid lubricant moves to an edge of a lower surface of the punch.

15. The battery case shaping method according to claim 11, wherein a region of the laminate sheet that is elongated by the pressing in step (c) is a side surface of the electrode assembly receiving portion and an outer circumferential portion of a bottom of the electrode assembly receiving portion.

16. A battery case manufactured using the battery case shaping apparatus according to claim 1, wherein a thickness of a smallest thickness portion of the battery case is 70% or more of a thickness of a largest thickness portion of the battery case.

17. The battery case shaping method according to claim 6, wherein the recess extends across a majority of the lower surface of the punch.

18. The battery case shaping method according to claim 6, wherein the recess extends across less than a majority of the lower surface of the punch.

19. The battery case shaping method according to claim 1, wherein an elongation region of the laminate sheet is extended to prevent the laminate sheet from being locally excessively elongated.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0039] FIG. 1 is a cross-sectional elevation view of a battery case manufacturing apparatus according to a first embodiment.

[0040] FIG. 2 is an exploded perspective view of the battery case manufacturing apparatus according to the first embodiment.

[0041] FIG. 3 is a cross-sectional elevation view of a battery case manufacturing apparatus according to a second embodiment.

[0042] FIG. 4 is a cross-sectional elevation view of a battery case manufacturing apparatus according to a third embodiment.

[0043] FIG. 5 is an exploded perspective view of the battery case manufacturing apparatus according to the third embodiment.

[0044] FIG. 6 is a cross-sectional elevation view of a battery case manufactured using the battery case manufacturing apparatus according to another embodiment.

[0045] FIG. 7 shows cross-sectional elevation views of a central part of a punch according to another embodiment.

[0046] FIG. 8 sequentially shows a battery case manufacturing process according to another embodiment.

DETAILED DESCRIPTION

[0047] Now, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings such that the preferred embodiments of the present invention can be easily implemented by a person having ordinary skill in the art to which the present invention pertains. In describing the principle of operation of the preferred embodiments of the present invention in detail, however, a detailed description of known functions and configurations incorporated herein will be omitted when the same may obscure the subject matter of the present invention.

[0048] In addition, the same reference numbers will be used throughout the drawings to refer to parts that perform similar functions or operations. In the case in which one part is said to be connected to another part throughout the specification, not only may the one part be directly connected to the other part, but also, the one part may be indirectly connected to the other part via a further part. In addition, that a certain element is included does not mean that other elements are excluded, but rather means that such elements may be further included unless mentioned otherwise.

[0049] In addition, a description to embody elements through limitation or addition may be applied to all inventions, unless particularly restricted, and does not limit a specific invention.

[0050] Also, in the description of the invention and the claims of the present application, singular forms are intended to include plural forms unless mentioned otherwise.

[0051] Also, in the description of the invention and the claims of the present application, “or” includes “and” unless mentioned otherwise. Therefore, “including A or B” means three cases, namely, the case including A, the case including B, and the case including A and B.

[0052] Embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0053] FIG. 1 is a cross-sectional elevation view of a battery case manufacturing apparatus according to a first embodiment, and FIG. 2 is an exploded perspective view of the battery case manufacturing apparatus according to the first embodiment.

[0054] Referring to FIGS. 1 and 2, the battery case manufacturing apparatus 100 includes a punch 110 configured to press a laminate sheet 101 in order to shape a battery case, a die 120 having formed therein an accommodation portion 121 having a size corresponding to an electrode assembly receiving portion that is shaped by the punch, a holder 130 configured to fix the outer periphery of the laminate sheet 101, and an elastic separator 140 located under the punch 110 in order to prevent direct contact between the punch 110 and the laminate sheet 101.

[0055] In order to manufacture a pouch-shaped battery case using the laminate sheet, the laminate sheet 101 is disposed on the die 120 having formed therein the accommodation portion 121 having the size corresponding to the electrode assembly receiving portion, the outer periphery of the laminate sheet 101 is fixed to the die using the holder 130, and the laminate sheet 101 is pressed by the punch 110, whereby the electrode assembly receiving portion may be shaped.

[0056] At this time, in order to prevent direct contact between the laminate sheet and the punch, the elastic separator 140 is disposed between the laminate sheet and the punch.

[0057] If the laminate sheet and the punch directly contact each other, slip does not easily occur due to friction between the surfaces of the laminate sheet and the punch. As a result, the region of the laminate sheet that is elongated is narrowed, and therefore only a local region of the laminate sheet is elongated. Specifically, since the portion of the laminate sheet that becomes a side wall of the electrode assembly receiving portion when the laminate sheet is shaped into a battery case is mainly elongated, the thickness of the portion is excessively reduced, and therefore the battery case is easily damaged.

[0058] Since a stick-slip phenomenon easily occurs on the surface of the laminate sheet and the surface of the punch, as described above, the laminate sheet may be locally excessively elongated, and therefore a battery case shaping defect rate may be increased.

[0059] The laminate sheet 101 is pressed by the punch 110 in the state in which the elastic separator 140 is disposed between the laminate sheet 101 and the punch 110, and therefore the surface of the laminate sheet and the surface of the punch do not directly contact each other. Consequently, it is possible to solve a conventional problem in that the laminate sheet is scratched due to a non-smooth surface of the punch or introduction of foreign matter between the punch and the laminate sheet.

[0060] The x-axis width w1 of the punch 110 may be less than the x-axis distance w2 between opposite sides of the die, and the x-axis distance w2 between opposite sides of the die may be less than the x-axis distance w3 between opposite sides of the holder.

[0061] Consequently, the punch may easily enter the die through the holder.

[0062] FIG. 3 is a cross-sectional elevation view of a battery case manufacturing apparatus according to a second embodiment of the present invention.

[0063] Referring to FIG. 3, the battery case shaping apparatus 200 includes a punch 210 configured to press a laminate sheet 201 in order to shape a battery case, a die 220 having formed therein an accommodation portion 221 having a size corresponding to an electrode assembly receiving portion that is shaped by the punch, a holder 230 configured to fix the outer periphery of the laminate sheet 201, and an elastic separator 240 located under the punch 210 in order to prevent direct contact between the punch 210 and the laminate sheet 201. The elastic separator 240 is fixed to the holder 230. The holder 230, to which the elastic separator 240 is fixed, is disposed on the laminate sheet 201, whereby the laminate sheet is fixed.

[0064] Since the elastic separator 240 is fixed to the holder 230, as described above, the state in which the elastic separator 240 is fixed to the holder may be stably maintained when the laminate sheet 201 is pressed by the punch 210.

[0065] For example, the elastic separator 240 may be attached to the lower surface of the holder 230, or may be fixed to the lower part of the side surface of the holder 230. When the elastic separator 240 is attached to the lower surface of the holder 230, the force of fixing the laminate sheet 201 may be further increased by a microscopically protruding portion formed as the result of coupling between the elastic separator 240 and the holder 230. When the elastic separator 240 is fixed to the lower part of the side surface of the holder 230, particularly when the elastic separator 240 is inserted into and fixed to a recess formed in the lower part of the side surface of the holder 230, the force of coupling between the elastic separator 240 and the holder 230 is further increased. As a result, coupling between the elastic separator and the holder is maintained even when the elastic separator 240 is excessively elongated. When the depth of the receiving portion is large, a more advantageous effect may be achieved.

[0066] Before the battery case is shaped by the punch, the lower surface of the punch is located parallel to the upper surface of the elastic separator 240. In addition, the elastic separator and the laminate sheet are located parallel to each other. When the elastic separator is pressed by the punch, therefore, the entire area of the punch may apply uniform pressure to the entire area of the elastic separator and the laminate sheet.

[0067] In this specification, force generated by the punch is applied to the elastic separator and the laminate sheet with the same magnitude and in the same direction, and deformation of the laminate sheet is identical to deformation of the elastic separator.

[0068] FIG. 4 is a cross-sectional elevation view of a battery case manufacturing apparatus according to a third embodiment, and FIG. 5 is an exploded perspective view of the battery case manufacturing apparatus according to the third embodiment.

[0069] Referring to FIGS. 4 and 5, the battery case shaping apparatus 300 includes a punch 310 configured to press a laminate sheet 301 in order to shape a battery case, a die 320 having formed therein an accommodation portion 321 having a size corresponding to an electrode assembly receiving portion that is shaped by the punch, a holder 330 configured to fix the outer periphery of the laminate sheet 301, and an elastic separator 340 located under the punch 310 in order to prevent direct contact between the punch 310 and the laminate sheet 301.

[0070] The elastic separator 340 is fixed to the holder 330. As a result, a space having the elastic separator as a lower surface thereof and the inner surface of the holder 330 as a side wall thereof is formed, and a liquid lubricant 350 is added into the space. Since the elastic separator is a watertight elastic separator, the liquid lubricant is not discharged through the elastic separator and is movable only in the space.

[0071] The liquid lubricant remarkably reduces the force of friction between the punch and the elastic separator, whereby the surface of the elastic separator and the surface of the punch may very smoothly slip relative to each other.

[0072] As a result, the region of the laminate sheet that is elongated by the punch is increased, and therefore the average elongation of the elongated region may be reduced. For example, the thickness of the laminate sheet in an elongated state may be about 70% or more the thickness of the laminate sheet before elongation.

[0073] For example, at least one selected from the group consisting of hydrocarbon-based oil, such as liquid paraffin, grease, mineral vegetable oil, an emulsified oil, an anti-emulsifier, a pour point depressant, a viscosity modifier, an antifoaming agent, mineral oil including pure mineral oil or pure mineral oil including an additive, a fatty oil including animal oil and vegetable oil, a blended oil of mineral oil and a fatty oil, and a synthetic oil may be used as the liquid lubricant.

[0074] In the case in which the liquid lubricant is used, as described above, it is possible to prevent a local region of the laminate sheet from being excessively elongated.

[0075] FIG. 6 is a cross-sectional elevation view of a battery case manufactured using the battery case manufacturing apparatus according to another embodiment. Referring to FIG. 6, an electrode assembly receiving portion 410 is concavely formed in the battery case 400. The electrode assembly receiving portion 410 may be constituted by a bottom 411 of the electrode assembly receiving portion and a side surface 412 of the electrode assembly receiving portion.

[0076] If no liquid lubricant is used, unlike the embodiments of the present disclosure, the laminate sheet is elongated only at a main elongation region E1. As a result, the average elongation of the main elongation region is high, whereby this region is weakened, and therefore the battery case may be easily damaged.

[0077] Since the liquid lubricant is used in the present disclosure, however, slip occurs well between the surface of the punch and the surface of the elastic separator. Consequently, the elongation region is extended to an additional elongation region E2 in addition to the main elongation region E1. That is, the region of the laminate sheet that is elongated may be the side surface 412 of the electrode assembly receiving portion and the outer circumferential portion of the bottom 411 of the electrode assembly receiving portion.

[0078] As the elongation region is extended, as described above, the average elongation is reduced, whereby it is possible to reduce a thickness reduction rate of the battery case even after the battery case is shaped, and it is possible to prevent the battery case from being locally weakened.

[0079] In the battery case manufactured using the battery case shaping apparatus according to the present disclosure, the thickness of the smallest thickness portion of the battery case may be 70% or more the thickness of the largest thickness portion of the battery case.

[0080] Referring back to FIGS. 4 and 5, a pad 360 is disposed in the accommodation portion 321 of the die 320 at the lower part thereof.

[0081] The pad 360 may be made of an elastic material so as to be contracted by the punch 310. The pad 360 may be formed in a quadrangular shape when viewed in plan and may be configured to have a structure in which a central part of the pad convexly protrudes and the thickness of the pad is gradually decreased toward the outer circumferential portion thereof. When the laminate sheet is pressed by the punch 310 so as to be shaped, first, the protruding central part of the pad comes into contact with the laminate sheet moved downwards by the punch. Subsequently, when the laminate sheet is continuously pressed downwards by the punch, the protruding central part of the pad is contracted, whereby the overall thickness of the pad becomes uniform. As a result, the bottom of the electrode assembly receiving portion may become flat.

[0082] In addition, since the elastic pad 360 is disposed, it is possible to prevent the outside of the lower surface of the laminate sheet from being scratched.

[0083] FIG. 7 shows cross-sectional elevation views of a central part of a punch according to another embodiment.

[0084] Referring to FIG. 7, a recess 411 or 511 is formed in the lower surface of the punch 410 or 510.

[0085] The recess 411 formed in the punch 410 is configured such that the central part of the lower surface of the punch becomes concave, and the recess 511 formed in the punch 510 is configured such that the entirety of the lower surface of the punch becomes concave.

[0086] A space is formed in the lower surface of the punch by the recess formed as described above. When the elastic separator and the laminate sheet are pressed by the punch, a portion of the liquid lubricant is gathered, and the remainder of the liquid lubricant moves to the edge of the lower surface of the punch.

[0087] The force of friction between the central part of the punch and the elastic separator is reduced by the liquid lubricant gathered in the recess.

[0088] FIG. 8 shows a battery case shaping method sequentially from left to right and from top to bottom.

[0089] The battery case shaping method includes a step of disposing a laminate sheet 301 on the die 320, a step of fixing the laminate sheet 301 to the die 320 using the holder 330, to which the elastic separator 340 is attached, and a step of pressing the elastic separator 340 and the laminate sheet 301 using the punch 310.

[0090] Before the laminate sheet 301 is pressed by the punch 310 after the laminate sheet 301 is fixed to the die 320, the liquid lubricant 350 is added to the space formed by the elastic separator 340 and the holder 330. Since the elastic separator is a watertight elastic separator, the liquid lubricant is not discharged to the outside of the elastic separator.

[0091] In the step of pressing the laminate sheet 310 using the punch 310, pressing is performed until the pad 360 disposed in the lower part of the accommodation portion of the die 320 is compressed and flat. Since the pad 360 is configured to have a structure in which the central part of the pad protrudes and the thickness of the pad is gradually decreased toward the outer circumferential portion thereof, first, the laminate sheet 301 comes into contact with the protrude central part of the pad 360.

[0092] When compression of the pad 360 starts, the central part of the pad 360 is in contact with the laminate sheet 301, but a space is formed between the outer circumferential portion of the pad 360 and the laminate sheet 301. As the result of pressing, the liquid lubricant 350 on the elastic separator 340 moves to the space formed between the laminate sheet 301 and the outer circumferential portion of the pad 360, i.e., the edge of the lower surface of the punch 310.

[0093] In the case in which a recess is formed in the lower surface of the punch 310, a portion of the liquid lubricant may be gathered in the recess, and therefore it is possible to reduce the force of friction between the punch and the elastic separator at the lower surface of the punch.

[0094] As the punch 310 is inserted into the accommodation portion of the die 320, the liquid lubricant 350 moves to the edge of the lower surface of the punch 310, and eventually moves along the side surface of the punch 310. As a result, the liquid lubricant 350 may be present not only between the lower surface of the punch 310 and the surface of the elastic separator 340 but also between the side surface of the punch 310 and the surface of the elastic separator 340, whereby it is possible to reduce the force of friction between the punch and the elastic separator. With progress of pressing, the liquid lubricant 350 more widely spreads due to a capillary phenomenon.

[0095] As described above, the pad, the central part of which is convex, is disposed at the lower part of the accommodation portion of the die, whereby the liquid lubricant may easily move to the main elongation region and the additional elongation region of the laminate sheet. Consequently, the force of friction between the surface of the elastic separator and the surface of the punch is minimized, whereby it is possible to widely secure the additional elongation region of the laminate sheet, and therefore it is possible to manufacture a battery case having a small local reduction in thickness.

[0096] Those skilled in the art to which the present invention pertains will appreciate that various applications and modifications are possible within the category of the present invention based on the above description.

DESCRIPTION OF REFERENCE SYMBOLS

[0097] 100, 200, 300: Battery case manufacturing apparatuses

[0098] 101, 201, 301: Laminate sheets

[0099] 110, 210, 310, 410, 510: Punches

[0100] 120, 220, 320: Dies

[0101] 121, 221, 321: Accommodation portions

[0102] 130, 230, 330: Holders

[0103] 140, 240, 340: Elastic separators

[0104] 411, 511: Recesses

[0105] 350: Liquid lubricant

[0106] 360: Pad

[0107] 400: Battery case

[0108] 410: Electrode assembly receiving portion

[0109] 411: Bottom of electrode assembly receiving portion

[0110] 412: Side surface of electrode assembly receiving portion

[0111] E1: Main elongation region

[0112] E2: Additional elongation region

[0113] The present invention relates to a battery case shaping apparatus including a punch configured to shape a battery case for pouch-shaped batteries, wherein the battery case shaping apparatus further includes an elastic separator capable of, when a laminate sheet that is used as the battery case is pressed by the punch, minimizing damage to the surface of the laminate sheet, and a battery case manufacturing method using the same, and therefore the present invention has industrial applicability.