Apparatus and method for manufacturing secondary battery

Abstract

The present invention relates to a secondary battery manufacturing apparatus and method, wherein, by heating an electrode laminate while simultaneously cooling separators located on both sides of an electrode laminate during a lamination process of a secondary battery, the invention prevents shrinkage of the separators, thereby reducing costs, facilitating production management, and enabling the manufacture of a secondary battery with improved safety. A secondary battery manufacturing apparatus according to the present invention comprises a conveying unit for conveying an electrode stack having a separator, a negative electrode, a separator, and a positive electrode stacked therein, a pair of heating units for heating the electrode stack conveyed by the conveying unit from the upper and lower sides, and a cooling unit for cooling the separator on both sides parallel to the conveying direction of the electrode stack in the electrode stack.

Description

Technology Field

[0001] The present invention relates to a secondary battery manufacturing apparatus and a manufacturing method, and provides a secondary battery manufacturing apparatus and a manufacturing method capable of manufacturing a secondary battery with improved safety, reduced costs by preventing shrinkage of the separator, and easy production management. Background Technology

[0002] Generally, a secondary battery refers to a battery that can be charged and discharged, unlike a primary battery which cannot be recharged. These secondary batteries are widely used in the field of advanced electronic devices such as mobile phones, laptops, and automobiles, and active research and development is currently underway.

[0003] Secondary batteries have a structure in which an electrode assembly and an electrolyte are housed within a case, such as a can or a pouch. The electrode assembly has a structure in which a positive electrode, a separator, and a negative electrode are repeatedly stacked; generally, it can be classified into a wound type, in which the positive electrode, separator, and negative electrode are stacked and then wound to be housed within a case, and a stacked type, in which the positive electrode, separator, and negative electrode are cut to a specific size and then stacked.

[0004] The above electrode assembly is manufactured through a lamination process, which includes a transfer step for transferring the electrode and the separator, a joining step for joining the electrode and the separator so that they are alternately arranged, with the electrode placed at the top, a heating step for heating the joined electrode and the separator, and a joining step for joining the heated electrode and the separator to manufacture a unit cell and manufacturing an electrode assembly including one or more of the unit cells.

[0005] Looking at the lamination process in detail, during the transfer and bonding stage, cut electrodes are placed at predetermined intervals on top of one or more continuously supplied separator membranes. Subsequently, during the heating stage, the bonded electrodes and separator membranes are heated to enhance the bonding strength between them. During the bonding stage, the electrode stack, in which the electrodes are laminated onto the separator membrane (unit cells formed with spacing between them), is rolled by passing it between a pair of rollers, thereby bonding the electrodes and separator membranes through heat and pressure. Afterward, the laminated electrodes and separator membranes are cut into unit cells to form an electrode assembly.

[0006] The electrode laminate is formed by stacking a separator sheet, a cathode, a separator sheet, and an anode in an overlapping manner. In this case, the separator sheet is formed to protrude to the side of the electrode laminate to surround the cathode, thereby preventing exposure of the cathode. However, when the electrode laminate is heated during the heating step of the lamination process, thermal shrinkage may occur in the separator sheet on the side portion that is not laminated, as shown in Fig. 1. In this case, the cathode is exposed, causing damage to the battery case, which leads to quality issues of the battery such as corrosion of the battery case and leakage of the electrolyte. Furthermore, if a short circuit occurs due to contact between the anode and the cathode, problems such as ignition or explosion of the battery may occur, posing a significant threat to user safety.

[0007] Therefore, to address this, conventional methods involved manufacturing larger separator sizes to account for thermal shrinkage; however, this leads to increased manufacturing costs, posing a problem of higher expenses. Additionally, while measures such as adjusting the residence time of the electrode stack within the heating device or opening parts of the device to reduce heat transfer to the sides of the electrode stack can be employed, the shrinkage of the separator persists, making it difficult to guarantee the quality and safety of the battery. The problem to be solved

[0008] The present invention has been devised to solve the above problems. The objective of the present invention is to provide a secondary battery manufacturing apparatus and a manufacturing method that can manufacture a secondary battery with reduced costs, easy production management, and improved safety by preventing shrinkage of the separator through heating the electrode laminate during the lamination process of the secondary battery and simultaneously cooling the separator located on both sides of the electrode laminate. means of solving the problem

[0009] A secondary battery manufacturing apparatus according to the present invention comprises a conveying unit for conveying an electrode stack having a separator, a negative electrode, a separator, and a positive electrode stacked therein, a pair of heating units for heating the electrode stack conveyed by the conveying unit from the upper and lower sides, and a cooling unit for cooling the separator on both sides parallel to the conveying direction of the electrode stack in the electrode stack.

[0010] The cooling section may be provided on both sides of the heating section parallel to the transport direction of the electrode stack.

[0011] The cooling unit may include a pair of guide members that guide the movement of the separator on both sides of the electrode stack and a cooling means provided on the guide members to cool the separator.

[0012] The guide member can have a flat surface that guides the separator.

[0013] The cooling means is an air injection unit provided in the guide member, and the air injection unit can cool the separator by injecting cooled air.

[0014] The air injection unit includes a nozzle, and the nozzle can cool the membrane by injecting cooled air into a space provided to guide the movement of the membrane between guide members.

[0015] The cooling means is a cooling pipe provided inside the guide member, and the cooling pipe can cool the separation membrane through the endothermic action of the cooled fluid flowing inside.

[0016] The cooling pipe may have a flat surface facing the space provided to guide the movement of the separator between the guide members.

[0017] The heating section can be block-shaped along a direction parallel to the transport direction of the electrode stack.

[0018] The heating section can be block-shaped in a direction orthogonal to the transport direction of the electrode stack.

[0019] A method for manufacturing a secondary battery according to the present invention comprises the steps of: transporting an electrode stack having a separator, a negative electrode, a separator, and a positive electrode stacked thereon; heating the transported electrode stack from the top and bottom; and cooling the separator on both sides parallel to the transport direction of the electrode stack in the electrode stack.

[0020] A heating step and a cooling step may be performed simultaneously, wherein the heating step is performed at the center of the electrode stack in which the separator, cathode, separator, and anode are overlapped, and the cooling step can be performed on both sides of the electrode stack in which the separator protrudes.

[0021] The cooling step can cool the membrane by injecting cooled air from an air injection unit.

[0022] The cooling step can cool the membrane through the endothermic reaction of the cooled fluid flowing inside the cooling pipe. Effects of the invention

[0023] The secondary battery manufacturing apparatus and method according to the present invention comprises a conveying unit for conveying an electrode stack in which a separator, a negative electrode, a separator, and a positive electrode are stacked, a pair of heating units for heating the electrode stack conveyed by the conveying unit from the upper and lower sides, and a cooling unit for cooling the separator on both sides parallel to the conveying direction of the electrode stack in the electrode stack, thereby preventing shrinkage of the separator, thereby reducing costs, facilitating production management, and enabling the manufacture of a secondary battery with improved safety. Brief explanation of the drawing

[0024] Figure 1 is a diagram illustrating the shrinkage of a separator located on the side of an electrode laminate in a conventional lamination process. FIG. 2 is a schematic plan view illustrating a secondary battery manufacturing apparatus according to Example 1 of the present invention. Figure 3 is a cross-sectional view showing the cross section of the A-A' plane of Figure 2. FIG. 4 is a cross-sectional view illustrating the secondary battery manufacturing apparatus of FIG. 3 equipped with a cooling means. Specifically, FIG. 4(a) is a drawing illustrating the cooling means including an air injection unit, and FIG. 4(b) is a drawing illustrating the cooling means including a cooling pipe. FIG. 5 is a plan view illustrating a block-shaped heating unit in a secondary battery manufacturing apparatus according to Example 1 of the present invention. Specific details for implementing the invention

[0025] Hereinafter, preferred embodiments of the present invention are described in detail with reference to the attached drawings so that those skilled in the art can easily implement the present invention. However, the present invention may be embodied in various different forms and is not limited or restricted by the following embodiments.

[0026] In order to clearly explain the present invention, detailed descriptions of related prior art that are irrelevant to the explanation or that may unnecessarily obscure the essence of the invention have been omitted. Furthermore, when assigning reference numerals to the components of each drawing in this specification, identical or similar reference numerals are assigned to identical or similar components throughout the entire specification.

[0027] Furthermore, terms and words used in this specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings, but should be interpreted in a meaning and concept consistent with the technical spirit of the invention, based on the principle that the inventor can appropriately define the concept of the terms to best describe his invention.

[0029] Example 1

[0030] FIG. 2 is a schematic plan view illustrating a secondary battery manufacturing apparatus according to Embodiment 1 of the present invention. FIG. 3 is a cross-sectional view illustrating a section cut along the A-A' plane of FIG. 2. FIG. 4 is a cross-sectional view illustrating a secondary battery manufacturing apparatus of FIG. 3 equipped with a cooling means. FIG. 5 is a plan view illustrating a heating unit in a secondary battery manufacturing apparatus according to Embodiment 1 of the present invention in a block-like configuration.

[0031] Referring to FIGS. 2 and 3, a secondary battery manufacturing apparatus according to Embodiment 1 of the present invention includes a transfer unit (not shown in the drawing), a heating unit (110), and a cooling unit (120). The transfer unit transfers an electrode stack (10) in which a separator (11), a negative electrode (12), a separator (11), and a positive electrode (13) are stacked. The heating unit (110) heats the electrode stack (10) transferred by the transfer unit, and a pair of units are positioned at the top and bottom of the electrode stack (10) to heat the upper and lower parts of the electrode stack (10).

[0032] In addition, the secondary battery manufacturing device according to Embodiment 1 of the present invention further includes a cooling unit (120) for cooling the separator (11) on both sides parallel to the transport direction of the electrode stack (10) in the electrode stack (10). By doing so, the secondary battery manufacturing device of the present invention can be formed such that the separator (11) sufficiently surrounds the negative electrode (12) by minimizing the shrinkage of the separator (11) on the side portion of the electrode stack (10), thereby preventing contact between the negative electrode (12) and the battery case and preventing short circuits, thereby improving the safety of the battery. In addition, since the thermal shrinkage of the separator (11) is minimized, costs can be reduced by using a separator (11) of an optimized size without considering the amount of shrinkage, and various types of separators (11) with different thermal shrinkage rates can be used, or shrinkage of the separator (11) can be prevented without being affected by the residence time of the electrode stack (10) within the device, making production management easier and ensuring uniform quality of the battery.

[0033] The cooling section (120) will be described in detail below with reference to FIGS. 2 and FIGS. 4. The cooling section (120) is provided on both sides of the heating section (110) parallel to the transport direction of the electrode stack (10), and may include a guide member (121) and a cooling means. The two sides of the heating section (110) parallel to the transport direction of the electrode stack (10) are places where lamination does not occur, and thus shrinkage of the separator (11) occurs. Therefore, the cooling section (120) is provided symmetrically on both sides of the heating section (110) parallel to the transport direction to uniformly prevent shrinkage of the separator (11).

[0034] The guide member (121) may be formed as an upper and lower pair to guide the movement of the separator (11) and may form a space, and the upper and lower pair of guide members (121) may be provided on each side of the electrode stack (10). That is, the guide member (121) ensures that the separator (11) is stably guided during the transfer process, and by forming a space between the guide members (121), the separator (11) can be cooled by a cooling means. In addition, the guide member (121) has no particular restrictions on its cross-section or shape, but the surface guiding the separator (11) can be formed flat, thereby maximizing the contact area between the guide member (121) and the separator (11) to maximize the cooling effect by the cooling means described later.

[0035] A cooling means may be provided on a guide member (121) as a means for cooling the separator (11). First, referring to FIG. 4(a), the cooling means is an air injection unit (122-1) provided on the guide member (121), and the separator (11) can be cooled by air-cooling by the air injection unit (122-1) injecting cooled air. In detail, the air injection unit (122-1) includes a nozzle, and the separator (11) can be cooled by injecting cooled air into a space provided for the nozzle to guide the movement of the separator (11) between the guide members (121). In this way, when cooled air is injected from the air injection unit (122-1) into the space where the separator (11) is located, the separator (11) can be effectively cooled while minimizing physical and chemical deformation of the separator (11) and the electrode stack (10). In addition, the air injection unit (122-1) may be provided in the form of a hole formed in the guide member (121) rather than a nozzle to discharge cooling air, or may be provided with a fan to generate cooling air.

[0036] Next, referring to FIG. 4(b), the cooling means may be a cooling pipe (122-2) provided inside the guide member (121). A cooled fluid (F) flows through the cooling pipe (122-2), and the membrane (11) can be cooled by water cooling through the endothermic action of the fluid (F). The fluid (F) may be cooling water or a cooled gas, and this is a method of cooling the membrane (11) more indirectly compared to the method using an air injection unit (122-1), and can also stably cool the membrane (11) without causing physical or chemical deformation of the membrane (11).

[0037] There are no special restrictions on the cross-sectional shape of the cooling pipe (122-2), and it does not necessarily have to match the cross-sectional shape of the guide member (121), but the surface facing the space between the pair of guide members (121), that is, the space provided to guide the movement of the separator (11), can be formed flat. This maximizes the contact area between the cooling pipe (122-2) and the separator (11) and maximizes the cooling effect of the separator (11).

[0038] Referring to FIG. 5(a), the heating unit (110) may be block-shaped along a direction parallel to the transport direction of the electrode stack (10). For example, it may include a first heating unit located on the left side with respect to the transport direction and having a cooling unit (120) attached to its left side, a second heating unit located on the right side with respect to the transport direction and having a cooling unit (120) attached to its right side, and a third heating unit located between the first heating unit and the second heating unit. When the heating unit (110) is block-shaped in this way, the secondary battery manufacturing device according to Embodiment 1 of the present invention can be applied variably according to the size of the electrode by adjusting the size and number of the third heating unit, in particular.

[0039] Also, referring to FIG. 5(b), the heating unit (110) can be blocked in a direction orthogonal to the transport direction of the electrode stack (10), thereby allowing the time during which the electrode stack (10) is heated and cooled by the heating unit (110) and the cooling unit (120) in the manufacturing device according to Example 1 of the present invention to be easily controlled.

[0041] Example 2

[0042] Example 2 of the present invention differs from Example 1 in that it is a method of manufacturing a secondary battery using the secondary battery manufacturing apparatus of Example 1.

[0043] Content common to Example 1 will be omitted as much as possible, and Example 2 will be described focusing on the differences. That is, it is obvious that if content not explained in Example 2 is necessary, it can be considered as content of Example 1.

[0044] The secondary battery manufacturing method according to the present invention includes a transfer step, a heating step, and a cooling step for an electrode stack (10). In the transfer step of the electrode stack (10), an electrode stack (10) having a separator (11), a negative electrode (12), a separator (11), and a positive electrode (13) stacked thereon is transferred. In the heating step of the electrode stack (10), the transferred electrode stack (10) is heated from the top and bottom. In addition, in the cooling step of the present invention, the separator (11) located on both sides of the electrode stack (10) parallel to the transfer direction of the electrode stack (10) is cooled. By doing so, the shrinkage of the separator (11) on the side portion of the electrode stack (10) is minimized and the exposure of the negative electrode (12) is prevented, thereby preventing damage to the battery case, corrosion, and the occurrence of a short circuit, and improving the safety of the battery. In addition, since the thermal shrinkage of the separator (11) is minimized, costs can be reduced by using a separator (11) of an optimized size, and by using various types of separators (11) with different thermal shrinkage rates or by preventing shrinkage of the separator (11) without being affected by the residence time of the electrode stack (10) in the device, production management becomes easier and the quality of the battery can be ensured uniformly.

[0045] The heating and cooling steps of the electrode stack (10) can be performed simultaneously. That is, the heating step can be performed at the center of the electrode stack (10) where the separator (11), cathode (12), separator (11), and anode (13) are stacked, and the cooling step can be performed on both sides of the electrode stack (10) where the separator (11) protrudes. By performing the heating and cooling steps simultaneously in this way, heat can be prevented from being transferred to the separator (11) protruding from the sides of the electrode stack (10) during the process of heating the electrode stack (10), thereby preventing thermal shrinkage from occurring. The heating and cooling steps can be performed by the heating unit (110) and the cooling unit (120), and the detailed configuration of the heating unit (110) and the cooling unit (120) and the resulting effects can be understood as being the same as described in Example 1.

[0046] The cooling step can be performed as an air-cooling method in which an air injection unit (122-1) injects cooled air to cool the separator (11). In this way, when air cooled from the air injection unit (122-1) is injected into the space where the separator (11) is located, the separator can be effectively cooled while minimizing physical and chemical deformation of the separator (11) and the electrode stack (10). Additionally, the cooling step can be performed as a water-cooling method in which the separator is cooled through an endothermic reaction of the cooled fluid flowing inside the cooling pipe (122-2). This is a method of cooling the separator (11) more indirectly compared to the method using the air injection unit (122-1), and the separator (11) can be stably cooled without causing physical and chemical deformation of the separator (11). Furthermore, the configuration of the air injection unit (122-1) and the cooling pipe (122-2) of Example 2 can be understood as being the same as that of Example 1.

[0047] Although the present invention has been described above by limited embodiments and drawings, the present invention is not limited thereto, and various implementations are possible within the scope of the technical spirit of the present invention and the equivalent scope of the claims described below by those skilled in the art to which the present invention belongs. Explanation of the symbols

[0048] 10: Electrode laminate 11: Separator 12: Cathode 13: Bipolar 110: Heating part 120: Cooling section 121: Absence of guide 122-1: Air injection unit 122-2: Cooling pipe F: Fluid

Claims

Claim 1 A secondary battery manufacturing apparatus comprising: a conveying unit for conveying an electrode stack having an electrode and a separator stacked therein; a heating unit for heating the electrode stack conveyed by the conveying unit from the upper and lower sides; and a cooling unit for cooling the separator, wherein a portion of the separator overlaps with the electrode in a stacking direction, and the remaining portion of the separator protrudes outwardly from the electrode in the electrode stack, the heating unit heats the portion of the separator, and the cooling unit cools the remaining portion of the separator. Claim 2 A secondary battery manufacturing apparatus according to claim 1, wherein the cooling unit is provided on both sides of the heating unit parallel to the transport direction of the electrode stack. Claim 3 A secondary battery manufacturing apparatus according to claim 1, wherein the cooling unit comprises: a pair of guide members that guide the movement of a separator on both sides of the electrode stack; and a cooling means provided on the guide members for cooling the separator. Claim 4 A secondary battery manufacturing apparatus according to paragraph 3, wherein the guide member is characterized in that the surface guiding the separator is formed flat. Claim 5 A secondary battery manufacturing apparatus according to paragraph 3, wherein the cooling means is an air injection unit provided in the guide member, and the air injection unit cools the separator by injecting cooled air. Claim 6 A secondary battery manufacturing apparatus according to claim 5, wherein the air injection unit includes a nozzle, and the nozzle cools the separator by injecting cooled air into a space provided to guide the movement of the separator between the guide members. Claim 7 A secondary battery manufacturing apparatus according to paragraph 3, wherein the cooling means is a cooling pipe provided inside the guide member, and the cooling pipe cools the separator through the endothermic action of the cooled fluid flowing inside. Claim 8 A secondary battery manufacturing apparatus according to claim 7, wherein the cooling pipe is characterized in that the surface facing the space provided to guide the movement of the separator between the guide members is formed flat. Claim 9 A secondary battery manufacturing apparatus according to claim 1, wherein the heating unit is formed into blocks along a direction parallel to the transport direction of the electrode stack. Claim 10 A secondary battery manufacturing apparatus according to claim 1, wherein the heating unit is formed into blocks in a direction orthogonal to the transport direction of the electrode stack. Claim 11 A method for manufacturing a secondary battery comprising: a transfer step for transferring an electrode stack having an electrode and a separator stacked thereon; a heating step for heating the transferred electrode stack from the top and bottom; and a cooling step for cooling the separator, wherein a portion of the separator overlaps with the electrode in a stacking direction, and the remaining portion of the separator protrudes outwardly from the electrode in the electrode stack, and the portion of the separator is heated in the heating step and the remaining portion of the separator is cooled in the cooling step. Claim 12 A method for manufacturing a secondary battery according to claim 11, wherein the heating step and the cooling step are performed simultaneously. Claim 13 A method for manufacturing a secondary battery according to claim 11, wherein the cooling step is characterized by cooling the separator by injecting air cooled from an air injection unit. Claim 14 A method for manufacturing a secondary battery according to claim 11, wherein the cooling step is characterized by cooling the separator through an endothermic reaction of the cooled fluid flowing inside the cooling pipe.

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