Laminator for Manufacture of Unit Structural Bodies with Increased Force of Adhesion

Abstract

A laminator is configured for increasing the force of adhesion between an electrode and a separator upon forming a unit structural body. The laminator is configured for heating a unit structural body sheet that includes an electrode and a separator in a stacked state and a press roll having a pair of upper and lower rolls configured to press the heated unit structural body sheet. The press roll is configured to raise its temperature. The average temperature of the press roll is higher than the temperature of the unit structural body sheet.

Claims

1. A laminator for manufacturing unit structural bodies, the laminator comprising: a heating means configured to heat a unit structural body sheet that includes an electrode and a separator in a stacked state; and a press roll comprising a pair of upper and lower rolls and configured to press the heated unit structural body sheet, wherein the press roll including a temperature raising means configured to raise a temperature of the press roll, and wherein an average temperature of the press roll, during a manufacture of the unit structural bodies, is higher than a temperature of the unit structural body sheet during the manufacture of the unit structural bodies.

2. The laminator according to claim 1, further comprising an air blower configured to inject air onto the press roll, the air blower having a temperature lower than the temperature of the press roll.

3. The laminator according to claim 2, wherein the air blower injects air to a middle part of the press roll such that a temperature of the middle part of the press roll is lower than a temperature of a peripheral part of the press roll.

4. The laminator according to claim 2, further comprising a further air blower, wherein the air blowers are disposed to inject air onto respective ones of the upper and the lower rolls of the press roll.

5. The laminator according to claim 3, wherein the air blower continuously injects air to the middle part of the press roll.

6. The laminator according to claim 1, wherein a length of each of the upper and the lower rolls in an axial direction is greater than a width of the unit structural body sheet.

7. The laminator according to claim 1, wherein each the upper and the lower rolls is rigid and roll made of metal.

8. The laminator according to claim 3, further comprising a temperature sensor configured to measure the temperature of the middle part of the press roll and the temperature of the peripheral part of the press roll.

9. A method for manufacturing a unit structural body with increased force of adhesion between an electrode and a separator, the method comprising: stacking a separator and an electrode cut to a predetermined size to form a unit structural body sheet; heating the unit structural body sheet; pressing the heated unit structural body sheet using a press roll to adhere the electrode and the separator to each other; and cutting the unit structural body sheet with the electrode and the separator adhered to each other, wherein during the pressing step, a temperature of a middle part of the press roll is lower than a temperature of a peripheral part of the press roll.

10. The method according to claim 9, wherein an average temperature of the press roll is higher than a temperature of the unit structural body sheet.

11. A battery cell comprising the unit structural body manufactured using the manufacturing method according to claim 9.

12. A battery pack comprising the battery cell according to claim 11.

13. A battery cell comprising the unit structural body manufactured using the manufacturing method according to claim 10.

14. A battery pack comprising the battery cell according to claim 13.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0033] FIG. 1 is a perspective view schematically showing a conventional unit structural body manufacturing apparatus.

[0034] FIG. 2 is a plan view schematically showing a portion of a conventional laminator for manufacture of unit structural bodies.

[0035] FIG. 3 is a plan view schematically showing a portion of a laminator and structural body sheet during the manufacture of unit structural bodies according to an embodiment.

[0036] FIG. 4 is a front view schematically showing a portion of the laminator and structural body sheet of FIG. 3 during the manufacture of unit structural bodies according to the embodiment.

[0037] FIGS. 5A and 5B are views showing a difference in position-based force of adhesion between (a) a unit structural body manufactured using the laminator for manufacture of unit structural bodies according to the embodiment and (b) a unit structural body manufactured using the conventional laminator for manufacture of unit structural bodies, respectively.

DETAILED DESCRIPTION

[0038] In the present application, it should be understood that the terms “comprises,” “has,” “includes,” etc. specify the presence of stated features, numbers, steps, operations, elements, components, or combinations thereof, but do not preclude the presence or addition of one or more other features, numbers, steps, operations, elements, components, or combinations thereof.

[0039] 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 in 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.

[0040] Hereinafter, a laminator for manufacture of unit structural bodies according to the present invention will be described with reference to the accompanying drawings.

[0041] FIG. 3 is a plan view schematically showing a portion of a laminator for manufacture of unit structural bodies according to an embodiment, and FIG. 4 is a front view schematically showing a portion of the laminator for manufacture of unit structural bodies according to the embodiment.

[0042] When describing the laminator 100 in detail with reference to FIGS. 3 and 4, the laminator 100 includes a heating means (not shown) configured to raise the temperature of a unit structural body sheet S, a press roll 110 configured to press the unit structural body sheet S, and an air blower 120.

[0043] First, the heating means is configured to raise the temperature of the unit structural body sheet before the unit structural body sheet is pressed by the press roll 110 in order to increase the force of adhesion between an electrode and a separator. A heating method is not particularly restricted. Any of known indirect heating methods based on radiation and convection may be selected and used.

[0044] In addition, it is preferable for heating temperature of the unit structural body sheet S to be between 60° C. and 105° C. If the heating temperature is lower than 60° C., it is difficult to secure the force of adhesion between the electrode and the separator. If the heating temperature is higher than 105° C., on the other hand, defects, such as performance deterioration, may occur due to shrinkage of the separator.

[0045] Next, the press roll 110, which is constituted by a pair of an upper press roll 111 and a lower press roll 112, presses the unit structural body sheet S passing between the upper press roll and the lower press roll while rotating such that the electrode and the separator are adhered to each other.

[0046] Consequently, the press roll 110 is formed such that the length of the press roll in an axial direction is greater than the width of the unit structural body sheet S that passes between the constituents of the press roll 110.

[0047] A temperature raising means (not shown) configured to raise the average temperature T.sub.2 of the press roll 110 is provided in the press roll 110. The temperature raising means heat the press roll 110 such that the average temperature T.sub.2 of the press roll 110 is higher than the temperature T.sub.1 of the unit structural body sheet S.

[0048] The temperature raising means is not particularly restricted as long as the temperature raising means is located in the press roll 110 so as to heat the press roll 110, and any of various known devices may be used.

[0049] Meanwhile, a rigid roll made of any of various metal materials is used as the press roll 110. The length of a metal is changed depending on a change in temperature thereof, i.e. the metal thermally expands, and each metal has an inherent coefficient of thermal expansion.

[0050] The coefficient of thermal expansion is typically classified into a coefficient of linear thermal expansion and a coefficient of volume thermal expansion. In the present disclosure, the “coefficient of thermal expansion” means the “coefficient of linear thermal expansion,” unless mentioned otherwise.

[0051] For example, stainless steel has a coefficient of thermal expansion of about 9 to 18 [10.sup.−6/° C.] within a range of 0 to 100° C. depending on the kind thereof.

[0052] Specifically, ferrite-based stainless steel has a coefficient of thermal expansion of about 9.3 to 12 [10.sup.−6/° C.], martensite-based stainless steel has a coefficient of thermal expansion of about 9.9 to 12 [10.sup.−6/° C.], and austenite-based stainless steel has a coefficient of thermal expansion of about 9.8 to 25 [10.sup.−6/° C.].

[0053] In the case in which the press roll 110 is made of a metal, such as stainless steel, therefore, a temperature gradient may occur in the press roll 110 depending on the position thereof, whereby a difference in thermal expansion may occur.

[0054] Also, in the laminator 100, the air blower 120, which is configured to inject air to the press roll 110, is further provided.

[0055] The air blower 120 is constituted by an upper air blower 121 corresponding to the upper press roll 111 and a lower air blower 122 corresponding to the lower press roll 112.

[0056] The air blower 120 injects air having a temperature lower than the average temperature T.sub.2 of the press roll 110 to a middle part R.sub.2 of the press roll 110 heated to a temperature higher than the temperature of the unit structural body sheet S by the temperature raising means such that the temperature of the middle part R.sub.2 of the press roll 110 is lower than the temperature of a peripheral part R.sub.1 of the press roll.

[0057] As a result, the peripheral part R.sub.1 of the press roll 110, which has a temperature higher than the temperature of the middle part R.sub.2 of the press roll 110, thermally expands much more than the middle part of the press roll, and much more pressure is applied to a peripheral part of the unit structural body sheet S by the peripheral part R.sub.1 having a diameter increased much more than the diameter of the middle part due to a difference in thermal expansion.

[0058] Consequently, the peripheral part of the unit structural body sheet S has force of adhesion higher than the force of adhesion at the remaining part of the unit structural body sheet, whereby it is possible to prevent poor adhesion at the peripheral part of the unit structural body sheet.

[0059] In addition, since the laminator 100 includes the air blower 120, as described above, the middle part R.sub.2 of the press roll 110 is constantly maintained at a temperature uniformly lower than the temperature of the peripheral part R.sub.1 of the press roll 110 without influences due to contact with the unit structural body sheet S from a start step of the process, whereby it is possible to press the unit structural body sheet S with a uniform pressure while the process is performed.

[0060] Meanwhile, the conditions of air injected by the air blower 120, such as the temperature, speed, and amount thereof, appropriately selected within a range within which the temperature of the middle part R.sub.2 of the press roll 110 approximates the temperature T.sub.1 of the unit structural body sheet S, although the conditions of the air are not particularly restricted.

[0061] A unit structural body with increased force of adhesion at a peripheral part thereof may be manufactured using the laminator 100 for manufacture of unit structural bodies.

[0062] When describing a method of manufacturing the unit structural body, first, a separator and an electrode cut to a predetermined size are stacked to form a unit structural body sheet, and the formed unit structural body sheet is introduced into the laminator and is heated using the heating means.

[0063] Subsequently, the unit structural body sheet is pressed using the press roll in the state in which the temperature of the peripheral part of the press roll is higher than the temperature of the middle part of the press roll to adhere the electrode and the separator to each other.

[0064] At this time, the average temperature of the press roll is higher than the temperature of the heated unit structural body sheet.

[0065] Finally, one electrode adhered to the separator and another electrode adhered to the separator are separated from each other by cutting to form a unit structural body with increased force of adhesion between the electrode and the separator at a peripheral part thereof.

[0066] As a result, it is possible to prevent defects that may occur due to separation between the electrode and the separator in a unit structural body transfer process or subsequent processes of manufacturing a battery cell using the unit structural body.

[0067] Unit structural bodies may be stacked to form an electrode assembly, the formed electrode assembly may be received in a case, and an electrolytic solution may be injected into the case to form a battery cell.

[0068] In addition, a plurality of battery cells may be connected to each other in series or in parallel, and various kinds of components may be added to manufacture a battery module or a battery pack. The manufactured battery module or battery pack is used as a power supply source for various kinds of devices.

[0069] FIGS. 5A and 5B are views showing a difference in position-based force of adhesion between (a) a unit structural body manufactured using the laminator for manufacture of unit structural bodies according to the embodiment of the embodiment and (b) a unit structural body manufactured using the conventional laminator for manufacture of unit structural bodies, respectively.

[0070] In FIGS. 5A and 5B, a darker portion indicates that the force of adhesion between the electrode and the separator is higher, and a brighter portion indicates that the force of adhesion between the electrode and the separator is lower.

[0071] In addition, the force of adhesion means the value of peel strength measured using an adhesive force measuring instrument at normal temperature.

[0072] When describing a difference in force of adhesion between the unit structural body according to the present disclosure and the conventional unit structural body with reference to FIGS. 5A and 5B, the force of adhesion of the unit structural body according to the present disclosure at the peripheral part thereof is high due to the press roll having great thermal expansion at the peripheral part thereof, as clearly shown in FIG. 5A, whereas the middle part of the unit structural body is pressed with higher pressure, whereby the force of adhesion of the unit structural body at the middle part thereof is high, as shown in FIG. 5B.

[0073] As can be seen therefrom, there is a definite difference in position-based force of adhesion between the unit structural body manufactured using the laminator 100 for manufacture of unit structural bodies and the unit structural body manufactured using the conventional laminator.

[0074] Although the specific details of the present invention have been described in detail, those skilled in the art will appreciate that the detailed description thereof discloses only preferred embodiments of the present invention and thus does not limit the scope of the present invention. Accordingly, those skilled in the art will appreciate that various changes and modifications are possible, without departing from the category and technical idea of the present invention, and it will be obvious that such changes and modifications fall within the scope of the appended claims.

DESCRIPTION OF REFERENCE SYMBOLS

[0075] 100: Laminator [0076] 110: Press roll [0077] 111: Upper press roll [0078] 112: Lower press roll [0079] 120: Air blower [0080] 121: Upper air blower [0081] 122: Lower air blower [0082] S: Unit structural body sheet [0083] R.sub.1: Peripheral part of press roll [0084] R.sub.2: Middle part of press roll [0085] T.sub.1: Temperature of unit structural body sheet [0086] T.sub.2: Average temperature of press roll