Secondary battery and method for manufacturing a secondary battery

Abstract

A method for manufacturing a secondary battery according to one embodiment of this document includes a first sealing step of sealing the periphery of a pouch-type outer casing material by forming a peripheral sealing portion on the periphery of the pouch-type outer casing material, which has a housing portion for housing an electrode assembly and a collection portion for collecting gas generated during the charging and discharging process of the electrode assembly; a degassing step of discharging the gas collected in the collection portion during the charging and discharging process of the electrode assembly to the outside of the pouch-type outer casing material; and a second sealing step of forming a partition sealing portion between the housing portion and the collection portion in the pouch-type outer casing material in order to partition the housing portion from the collection portion after the degassing step, wherein the first sealing step may further include forming an additional sealing portion that extends in a direction traversing between the housing portion and the collection portion at the peripheral sealing portion and is located on the collection portion side, separated from the partition sealing portion.

Description

Technical Field

[0001] [Cross - reference to Related Applications] This application claims the benefit of priority based on Korean Patent Application No. 10 - 2023 - 0121139, filed on September 12, 2023, and all the contents disclosed in the Korean Patent Application are incorporated herein by reference.

[0002] Embodiments of this document relate to a secondary battery and a method for manufacturing a secondary battery.

Background Art

[0003] Generally, unlike a primary battery that cannot be charged, a secondary battery means a battery that can be charged and discharged, and is widely used in electronic devices such as mobile phones, laptop computers, camcorders, or electric vehicles.

[0004] Secondary batteries can be classified into cylindrical and prismatic batteries in which an electrode assembly is built into a cylindrical or prismatic metal can according to the shape of the battery case, and pouch - type batteries in which the electrode assembly is built into a pouch - type case of a laminate sheet.

[0005] FIG. 1 is a diagram showing an example of a pouch - type secondary battery. The pouch - type secondary battery 1 (pouch - type cell) includes an electrode assembly 2 formed by alternately laminating electrodes and a separator, and a pouch - type exterior material 20 in which the electrode assembly 2 is accommodated. Electrode tabs 15 may be respectively connected to the electrodes of the electrode assembly 2. After the electrode tabs 15 are welded to each other in a predetermined area, they may be connected to an electrode lead 17 by welding. The exterior material 20 includes a housing part 21 (cup part) for accommodating the electrode assembly 2. The housing part 21 of the exterior material 20 may be formed of one or two recessed portions. In FIG. 1, a housing part 21 formed of two recessed portions is illustrated. Such an exterior material 20 may be manufactured by molding a pouch film. A sealing part 23 is formed by sealing around the housing part 21.

[0006] On the other hand, in order to activate the secondary battery, activation gas may be generated during the charging and discharging process of the electrode assembly. This activation gas can increase the internal pressure of the pouch-type outer material, causing stress to concentrate in specific parts of the pouch-type outer material. This can lead to deformation, cracks, wrinkles, and other problems in those specific parts of the pouch-type outer material. When deformation or other problems occur in the pouch-type outer material, the insulation performance of the pouch-type outer material may also decrease. To resolve these problems, it may be considered to form sealing sections in many parts of the pouch-type outer material. However, this may result in overlapping of the sealing sections, and this overlapping of sealing sections may actually weaken the sealing performance of the sealing sections. [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] The embodiments described herein aim to provide a secondary battery and a method for manufacturing a secondary battery that, even if the internal pressure of the pouch-type outer material increases due to gas generated during the activation process, does not cause deformation, cracks, wrinkles, etc., in specific parts of the pouch-type outer material, thereby preventing a decrease in the insulation performance of the pouch-type outer material.

[0008] Furthermore, the embodiments described in this document aim to provide a secondary battery and a method for manufacturing a secondary battery that do not cause deformation due to increased internal pressure in specific parts of the pouch-type exterior material, nor cause a decrease in sealing performance due to the superposition of sealing parts. [Means for solving the problem]

[0009] In one example, a method for manufacturing a secondary battery includes a first sealing step of sealing the periphery of a pouch-type outer casing material by forming a peripheral sealing portion on the periphery of the pouch-type outer casing material, which has a housing portion for housing an electrode assembly and a collection portion for collecting gas generated during the charging and discharging process of the electrode assembly; a degassing step of discharging the gas collected in the collection portion during the charging and discharging process of the electrode assembly to the outside of the pouch-type outer casing material; and a second sealing step of forming a partition sealing portion between the housing portion and the collection portion in the pouch-type outer casing material in order to partition the housing portion from the collection portion after the degassing step, wherein the first sealing step may further include forming an additional sealing portion that extends in a direction traversing between the housing portion and the collection portion at the peripheral sealing portion and is located on the collection portion side, separated from the partition sealing portion.

[0010] In another example, the additional sealing portion may be arranged so as not to overlap with the partition sealing portion.

[0011] In yet another example, the additional sealing portion may extend from the peripheral sealing portion and include a curved portion that is recessed in a curved shape defined by a predetermined radius from a predetermined point in the pouch-type outer material that is separated from the additional sealing portion toward the housing portion.

[0012] In yet another example, the separation distance between the additional sealing portion and the partition sealing portion may be at least half of the radius of the curved portion and less than or equal to the radius, in a direction perpendicular to the extension direction of the partition sealing portion.

[0013] In yet another example, if E is the length of the additional sealing portion defined in the extension direction of the additional sealing portion, L is the length of the pouch-type outer material defined in the direction corresponding to the extension direction of the additional sealing portion, and R is the radius of the curved portion, then the condition 0.06*L-2*R≦E≦0.06*L can be satisfied.

[0014] In yet another example, the peripheral sealing portion may include a first horizontal portion provided on the side from which the electrode lead electrically connected to the electrode assembly is drawn out, and formed in a horizontal direction perpendicular to the direction in which the electrode lead is drawn out; a first extension portion extending from one end of the first horizontal portion that is adjacent to the collection portion, in a direction away from the first horizontal portion until it exceeds the housing portion; a second extension portion extending from the end of the first extension portion, inclined toward the outside of the pouch-type outer material in a direction horizontally away from the first extension portion; and a second horizontal portion extending from the end of the second extension portion in a direction horizontally away from the second extension portion.

[0015] In yet another example, the first extension may include an inclined extension extending from one end of the first horizontal portion, inclined toward the inside of the pouch-type exterior material in a direction horizontally away from the first horizontal portion, and a horizontal extension extending from the end of the inclined extension portion in a direction horizontally away from the inclined extension portion.

[0016] In yet another example, the peripheral sealing portion may further include a third extension that extends from the other end of the first horizontal portion that is located further away from the collection portion, inclined toward the inside of the pouch-type outer material in a direction horizontally away from the first horizontal portion.

[0017] In yet another example, the connection point between the additional sealing portion and the peripheral sealing portion may be located within the first extension portion and the second extension portion.

[0018] In yet another example, the secondary battery includes a pouch-type outer casing comprising a housing portion for housing an electrode assembly and a collection portion for collecting gas generated during the charging and discharging process of the electrode assembly; a peripheral sealing portion for sealing the periphery of the pouch-type outer casing; a partition sealing portion of the pouch-type outer casing that seals the space between the housing portion and the collection portion, thereby separating the housing portion from the collection portion; and an additional sealing portion of the pouch-type outer casing that seals a predetermined area of ​​the collection portion, wherein the additional sealing portion extends in a direction corresponding to the extension direction of the partition sealing portion at the peripheral sealing portion and is arranged at a distance from the partition sealing portion.

[0019] In yet another example, the additional sealing portion may be arranged so as not to overlap with the partition sealing portion.

[0020] In yet another example, the additional sealing portion may extend from the peripheral sealing portion and include a curved portion that is recessed in a curved shape defined by a predetermined radius from a predetermined point in the pouch-type outer material that is separated from the additional sealing portion toward the housing portion.

[0021] In yet another example, the separation distance between the additional sealing portion and the partition sealing portion may be at least half of the radius of the curved portion and less than or equal to the radius, in a direction perpendicular to the extension direction of the partition sealing portion.

[0022] In yet another example, if E is the length of the additional sealing portion defined in the extension direction from the peripheral sealing portion to the additional sealing portion, L is the length of the pouch-type outer material defined in the direction corresponding to the extension direction of the additional sealing portion, and R is the radius of the curved portion, then the condition 0.06*L-2*R≦E≦0.06*L can be satisfied. [Effects of the Invention]

[0023] According to one embodiment of this document, by increasing the mechanical rigidity of the pouch-type exterior material through an additional sealing portion, even if the internal pressure of the pouch-type exterior material increases due to the gas generated during the activation process, it is possible to reduce or eliminate problems such as deformation, cracks, and wrinkles occurring in specific parts of the pouch-type exterior material. As a result, it is also possible to prevent a decrease in the insulation performance of the pouch-type exterior material.

[0024] Moreover, according to one embodiment of this document, by arranging the additional sealing portion at a distance from the partition sealing portion, it is possible to reduce or eliminate the problem of a decrease in sealing performance due to the overlap of the sealing portions.

Brief Description of the Drawings

[0025] [Figure 1] It is a diagram showing an example of a pouch-type secondary battery. [Figure 2] It is a plan view for sequentially explaining the manufacturing method of the secondary battery according to Example 1 of this document. [Figure 3] It is a plan view for sequentially explaining the manufacturing method of the secondary battery according to Example 1 of this document. [Figure 4] It is a plan view for sequentially explaining the manufacturing method of the secondary battery according to Example 1 of this document. [Figure 5] It is a plan view for sequentially explaining the manufacturing method of the secondary battery according to Example 1 of this document. [Figure 6] It is a plan view for sequentially explaining the manufacturing method of the secondary battery according to Example 1 of this document. [Figure 7] It is a cross-sectional view showing the laminated structure of the pouch-type exterior material in FIG. 2. [Figure 8] It is a plan view for explaining the secondary battery according to Example 2 of this document.

Modes for Carrying Out the Invention

[0026] Preferred embodiments of the present invention will be described in detail below with reference to the attached drawings, so that those with ordinary skill in the art to which the present invention pertains can easily implement it. However, the present invention may be embodied in a variety of different forms and is not limited to or restricted by the following embodiments.

[0027] In order to clearly explain the present invention, detailed descriptions of prior art that are irrelevant to the description or that may obscure the essence of the invention are omitted. In this specification, when assigning reference numerals to components in each drawing, the same reference numeral is used throughout the specification for identical or similar components.

[0028] Furthermore, the terms and words used in this specification and the claims shall not be interpreted in a manner limited to their ordinary and lexicographical meanings, but rather in a manner consistent with the technical idea of ​​the present invention, in accordance with the principle that inventors may define the concepts of terms as appropriate to best describe their invention.

[0029] Example 1 The method for manufacturing a secondary battery according to Example 1 of this document will be described sequentially below with reference to Figures 2 to 6. Figures 2 to 6 are plan views illustrating the method for manufacturing a secondary battery according to Example 1 of this document. For reference, the contents of Example 1 may also be applied to the examples described later, as long as they do not contradict each other.

[0030] Preparation of pouch-type exterior materials First, a pouch-type exterior material 110 may be prepared. The pouch-type exterior material 110 may be prepared in the form of a single exterior material sheet 120 folded. Alternatively, the pouch-type exterior material may be prepared in the form of two exterior material sheets overlapping each other. Figure 2 illustrates a pouch-type exterior material 110 in the form of a single exterior material sheet 120 folded along a predetermined reference line (F) (see the pouch-type exterior material in Figure 1).

[0031] The exterior material sheet 120 may be a laminate sheet including a metal layer 121 and resin layers 122 and 123 laminated on the metal layer 121, as shown in Figure 7. The metal layer 121 may include a layer of aluminum or a layer of stainless steel. The resin layer may include a first resin layer 122 disposed on the inner surface of the metal layer 121. The first resin layer 122 may be a layer formed of polypropylene (PP) or polyphthalamide (PPA). Since high insulation and corrosion resistance may be required for the first resin layer 122, the first resin layer 122 may be formed of other resins that satisfy these requirements. The resin layer may include a second resin layer 123 disposed on the outer surface of the metal layer 121. The second resin layer 123 may be a layer formed of polyethylene terephthalate (PET). Since the second resin layer 123 may be required to provide protection and insulation for the secondary battery, the second resin layer 123 may be formed from another resin that satisfies these requirements.

[0032] The pouch-type outer packaging material 110 may include a housing portion 111 for housing the electrode assembly 140, as shown in Figure 2. The housing portion 111 may be pre-formed in the outer packaging material sheet 120. For example, the outer packaging material sheet 120 may be pressed with a punch to indent a predetermined portion of the outer packaging material sheet 120 inward, thereby pre-forming a predetermined space for housing the electrode assembly 140 in a predetermined portion of the outer packaging material sheet 120. With the electrode assembly 140 housed in the housing portion 111 of the outer packaging material sheet 120, the outer packaging material sheet 120 can be folded along a predetermined reference line (F) to prepare the pouch-type outer packaging material 110 shown in Figure 2 (before the peripheral sealing portion described later is formed).

[0033] The pouch-type outer packaging material 110 may include a collection section 112 for collecting gases. Gases may be generated during the charging and discharging process of the electrode assembly 140 for activating the secondary battery. The collection section 112 may include a predetermined space that is in communication with the housing section 111 in order to collect such gases. The predetermined space of the collection section 112 may be formed in the space between the outer packaging material sheets 120 that are stacked facing each other, without the need for separate molding. The collection section 112 may refer to the portion of the pouch-type outer packaging material 110 located to the right of the housing section 111 in Figure 2.

[0034] For reference, the electrode assembly 140 may be formed by alternately stacking electrodes and separator films. The electrodes may include a positive electrode and a negative electrode. The electrode assembly 140 may be provided with electrode tabs connected to the electrodes. The electrode tabs may be provided separately or as part of the current collector constituting the electrodes. The electrode tabs may be welded to each other in a predetermined area and then connected to the electrode lead 141 by welding.

[0035] Peripheral sealing of pouch-type exterior materials Next, as shown in Figure 2, peripheral sealing portions 130;131, 132 can be formed on the upper peripheral portion 113a and the lower peripheral portion 113b of the pouch-type exterior material 110, respectively. This allows the upper peripheral portion 113a and the lower peripheral portion 113b of the pouch-type exterior material 110 to be sealed. Sealing may be carried out by heat-sealing the opposing resin layers 122 (see Figure 7) of the exterior material sheet 120, or by welding the opposing metal layers 121 (which may require removal of the resin layers) of the exterior material sheet 120 together. Other sealing methods may be carried out in a similar manner. For reference, the specific directions described in this document are relative concepts and may change depending on the viewing direction. For example, the upper and lower sides may be the left and right sides depending on the viewing direction.

[0036] In Figure 2, the right peripheral portion 113c of the pouch-type outer packaging material 110 may be an open portion. This can be used as an opening for injecting the electrolyte, as will be described later. In Figure 2, the left peripheral portion 113d of the pouch-type outer packaging material 110 is a folded portion, so a peripheral sealing portion 130 for sealing may be unnecessary.

[0037] The upper peripheral sealing portion 131 formed on the upper peripheral portion 113a of the pouch-type outer material 110 may include a first horizontal portion 131a provided on the side from which the electrode lead 141, which is electrically connected to the electrode assembly 140, is drawn out. The first horizontal portion 131a may be formed in a horizontal direction (see X direction) perpendicular to the direction (see Y direction) in which the electrode lead 141 is drawn out. In this document, horizontal and perpendicular may include substantially horizontal and substantially perpendicular cases, respectively.

[0038] The upper peripheral sealing portion 131 may include a first extension portion 131b that extends from one end of the first horizontal portion 131a that is adjacent to the collection portion 112, in a direction away from the first horizontal portion 131a (for example, in the X direction in Figure 2). The first extension portion 131b may extend beyond the housing portion 111. For example, the first extension portion 131b may extend to the right of the boundary line (C) set to correspond to the right peripheral edge of the housing portion 111 in Figure 2.

[0039] The first extension 131b may include an inclined extension 131b1 that extends inclined from one end of the first horizontal section 131a. The inclined extension 131b1 may extend inclined toward the inside of the pouch-type exterior material 110 (for example, downward in Figure 2) with respect to the direction of horizontal separation of the first horizontal section 131a (see X direction). The first extension 131b may include a horizontal extension 131b2 that extends from the end of the inclined extension 131b1. The horizontal extension 131b2 may extend in the direction of horizontal separation of the inclined extension 131b1 (for example, in the X direction). The first extension may be formed inclined overall without the horizontal extension 131b2.

[0040] The upper peripheral sealing portion 131 may include a second extension portion 131c that extends inclined from the end of the first extension portion 131b (the end of the horizontal extension portion in Figure 2). The second extension portion 131c may extend inclined toward the outward direction of the pouch-type exterior material 110 (for example, the upward direction in Figure 2) with respect to the direction in which the first extension portion 131b moves away horizontally.

[0041] The upper peripheral sealing portion 131 may include a second horizontal portion 131d extending from the end of the second extension portion 131c. The second horizontal portion 131d may extend horizontally away from the second extension portion 131c. The second horizontal portion 131d may be located below the first horizontal portion 131a.

[0042] The upper peripheral sealing portion 131 may include a third extension portion 131e that extends inclined from the other end of the first horizontal portion 131a that is located further away from the collection portion 112. The third extension portion 131e may extend inclined toward the inside of the pouch-type outer material 110 (for example, the downward direction in Figure 2) with respect to the direction in which the first horizontal portion 131a moves away horizontally.

[0043] In the case of the pouch-type outer packaging material of this embodiment, the outer portions of the first extension 131b and the third extension 131e of the pouch-type outer packaging material can be removed. In the space secured by such removal (not occupied by the pouch-type outer packaging material), predetermined components (e.g., bolts) of the module or pack in which the secondary battery is placed can be arranged. This makes it possible to improve the energy density of the module or pack. The manufacturing method of this embodiment can improve the energy density of the module or pack to which the secondary battery manufactured by this embodiment is applied, while also preventing a decrease in the insulation performance of the pouch-type outer packaging material, as will be described later.

[0044] The lower peripheral sealing portion 132 formed on the lower peripheral portion 113b of the pouch-type outer material 110 may be formed in a shape symmetrical to the upper peripheral sealing portion 131.

[0045] Next, an electrolyte solution can be injected into the inside of the pouch-type outer packaging material 110. The right peripheral edge portion 113c of the pouch-type outer packaging material 110, which is open, may be used for injecting the electrolyte solution.

[0046] Next, as shown in Figure 3, a right peripheral sealing portion 133 can be formed on the right peripheral portion 113c of the pouch-type outer material 110. This allows the open right peripheral portion 113c to be sealed. In this embodiment, the peripheral sealing portion 130 may include the right peripheral sealing portion 133 together with the upper and lower peripheral sealing portions 131 and 132.

[0047] Emission of collected gas (degassing) Next, during the charging and discharging process of the electrode assembly 140, the gas collected in the collection section 112 can be discharged to the outside of the pouch-type outer packaging material 110. The electrode assembly 140 can be activated by charging and discharging it via the electrode leads 141 exposed to the outside of the pouch-type outer packaging material 110, and gas may be generated during such an activation process. The generated gas can be moved from the containment section 111 to the collection section 112 and collected in the collection section 112. To discharge the collected gas, a hole (H) can be formed in the pouch-type outer packaging material 110 as shown in Figure 4. The gas collected in the collection section 112 can be discharged to the outside of the pouch-type outer packaging material 110 through such a hole (H). To facilitate gas discharge, the gas discharge may proceed with the pouch-type outer packaging material 110 placed inside a negative pressure chamber (not shown).

[0048] Formation of partition sealing section Next, as shown in Figure 5, a partition sealing portion 150 can be formed between the housing portion 111 and the collection portion 112 of the pouch-type outer casing material 110. The collection portion 112 can be removed after degassing, but it is necessary to partition the housing portion 111 from the collection portion 112 before such removal, and for this purpose, the partition sealing portion 150 can be formed. After the partition sealing portion 150 is formed, the right-hand portion of the partition sealing portion 150 of the pouch-type outer casing material 110 can be removed to prepare the final secondary battery product as shown in Figure 6.

[0049] The compartment sealing portion 150 may include a sealing portion 151 on which actual sealing is performed, as shown in Figure 5. The sealing portion 151 may be the portion of the compartment sealing portion 150 that is located furthest from the housing portion 111. The sealing portion 151 may be formed to be approximately 5 mm wide, for example.

[0050] The compartment sealing portion 150 may include a temporary fixing portion 152 positioned next to the sealing portion 151. The process of forming the sealing portion may be described as a process in which the resin layer 122 (see Figure 7) of the pouch-type exterior material 110 is melted with heat and pressure and then solidified again. In such a process, the resin layer 122 of a predetermined portion of the pouch-type exterior material 110 (the portion that will hereafter become the sealing portion) melts and flows to the portion adjacent to the predetermined portion, thereby forming a temporary fixing portion 152 next to the sealing portion 151. The temporary fixing portion 152 may be formed to a width of approximately 2 mm, for example.

[0051] The compartment sealing portion 150 may include an unsealed portion 153 positioned next to the temporary-attached portion 152. The unsealed portion 153 may be a portion where sealing has not progressed and the opposing exterior material sheets 120 do not adhere to each other. The compartment sealing portion 150 can be folded towards the housing portion 111 after the collection portion 112 is removed. Such folding can reduce the space occupied by the secondary battery and improve the volumetric energy density of the secondary battery. The unsealed portion 153 of the compartment sealing portion 150 may be provided to allow folding of the compartment sealing portion 150. If the unsealed portion 153 is not sufficiently provided and folding occurs in the temporary-attached portion 152, there is a possibility that the sealing will be damaged in the temporary-attached portion 152 where sealing is not properly formed. The unsealed portion 153 may be provided with a width of approximately 2 mm, for example.

[0052] Formation of additional sealing portion On the other hand, as shown in Figure 2, an additional sealing portion 160 may be formed separately from the peripheral sealing portion 130. The additional sealing portion 160 is a sealing portion that extends from the peripheral sealing portion 130 and may extend in a direction that crosses between the housing portion 111 and the collection portion 112. For example, the additional sealing portion 160 may extend in a direction that substantially corresponds to the extension direction of the compartmental sealing portion 150 that is formed after the formation of the additional sealing portion 160. Figure 2 illustrates an additional sealing portion 160 that is formed in the vertical direction, which is the direction in which the electrode lead 141 is exposed. The additional sealing portion 160 may include an upper additional sealing portion 161 formed from the upper peripheral sealing portion 131 toward the lower peripheral sealing portion 132, and a lower additional sealing portion 162 formed from the lower peripheral sealing portion 132 toward the upper peripheral sealing portion 131.

[0053] The additional sealing portion 160 may be formed during the formation process of the peripheral sealing portion 130, or before or after the formation process of the peripheral sealing portion 130. The additional sealing portion 160 may extend immediately from the peripheral sealing portion 130, as shown in Figure 2, or it may extend at a distance from the peripheral sealing portion 130. If the additional sealing portion 160 extends immediately from the peripheral sealing portion 130, the connection point between the additional sealing portion 160 and the peripheral sealing portion 130 may be located within the first extension portion 131b and the second extension portion 131c. For example, the connection point may be located in the first extension portion 131b, in the second extension portion 131c, or spanning both. In Figure 5, the connection point is located spanning the horizontal extension portion 131b2 of the first extension portion 131b and the second extension portion 131c.

[0054] The gas generated during the activation process can increase the internal pressure of the pouch-type outer material 110, potentially concentrating stress in specific parts of the pouch-type outer material 110. This can lead to deformation, cracks, wrinkles, and other problems in those specific parts of the pouch-type outer material 110. The manufacturing method in this embodiment reduces or eliminates such problems by forming an additional sealing portion 160 between the containment portion 111 and the collection portion 112, thereby increasing the mechanical rigidity of the pouch-type outer material 110. If deformation does not occur in the pouch-type outer material 110, the decrease in insulation performance caused by deformation can also be prevented.

[0055] On the other hand, the additional sealing portion 160 may be positioned at a distance from the partition sealing portion 150, as shown in Figure 5 (see isolation distance D). Overlapping sealing portions may actually lead to a decrease in sealing performance. For example, if heat and pressure are applied again to a portion that has been primarily sealed by applying heat and pressure, the primary sealing may be weakened by the subsequent heat and pressure. In this embodiment, in order to prevent such problems from occurring, the additional sealing portion 160 can be positioned at a distance from the partition sealing portion 150.

[0056] The additional sealing portion 160 may be located on the side of the pouch-type outer packaging material 110 where the collection portion 112 is located, for example, to the right of the housing portion 111 in Figure 5.

[0057] The additional sealing portion 160 may be spaced approximately 11 mm away from the housing portion 111 in the X direction in Figure 5. The width of the additional sealing portion 160 (which may be defined in the X direction in Figure 5) may be approximately 10 mm. The length of the additional sealing portion 160 (see E in Figure 5) may be approximately 15 mm. Lengths of approximately 8.5 mm or approximately 2.5 mm may also be considered for the additional sealing portion 160.

[0058] On the other hand, the additional sealing portion 160 may include a curved portion 163 extending from the peripheral sealing portion 130, as shown in Figure 2. The curved portion 163 may be a portion formed by recessing in a curved shape defined by a predetermined radius (R) from a predetermined point (P) in the pouch-type outer material 110. The predetermined point (P) may be any point in the pouch-type outer material 110 that is separated from the additional sealing portion 160 toward the housing portion 111. Figure 2 illustrates a curved portion 163 defined by a quadrant drawn around the predetermined point (P).

[0059] If the additional sealing portion 160 is extended vertically from the peripheral sealing portion 130 without including the curved portion 163, stress may concentrate in the vertical portion when the internal pressure of the pouch-type outer material 110 increases due to the gas generated during the activation process, potentially causing damage to the sealing portion and the pouch-type outer material 110. Furthermore, the sealing tool must also be formed vertically to create the vertical portion, and the sharp shape of the vertical portion of the sealing tool may damage the pouch-type outer material 110. To prevent such problems, in this embodiment, the additional sealing portion 160 may include the curved portion 163.

[0060] The following explanation will be given with reference to Figure 5. The additional sealing section 160 is mainly intended to suppress deformation of the pouch-type outer packaging material 110 on the containment section 111 side, and therefore may be placed adjacent to the containment section 111. However, if the additional sealing section 160 is placed very close to the containment section 111, there is a possibility that it will overlap with the compartment sealing section 150. Also, if the additional sealing section 160 is placed very close to the containment section 111, the flow path formed between the additional sealing section 160 and the containment section 111 (see arrow in Figure 3) becomes very narrow, and there is a possibility that the sealing section may be damaged as the gas generated during the activation process moves to the collection section 112.

[0061] Taking these points into consideration, the separation distance (D) between the additional sealing portion 160 and the compartment sealing portion 150 may be more than half of the radius (R) of the curved portion 163 and less than or equal to the radius (R). If the separation distance between the additional sealing portion 160 and the compartment sealing portion 150 is D and the radius of the curved portion 163 is R, then R / 2 ≤ D ≤ R may be satisfied. For example, if R is 4 mm, the minimum value of D may be 2 mm.

[0062] When the isolation distance D is R / 2, some overlap (see the darkened area A) may occur between the additional sealing section 160 and the compartment sealing section 150, as shown in Figure 5. However, it was experimentally confirmed that this hardly causes any problems because the overlapping area is very small. Furthermore, if the separation distance D is greater than R, the additional sealing section 160 will be very far from the housing section 111, which may hinder the effect of suppressing deformation of the housing section 111. For reference, the separation distance (D) between the additional sealing section 160 and the compartment sealing section 150 can be measured in a direction perpendicular to the direction of extension (direction X in Figure 5) when the additional sealing section 160 and the compartment sealing section 150 are extended in the same direction.

[0063] In Figure 5, the additional sealing portion 160 and the partition sealing portion 150 are shown to partially overlap, but the additional sealing portion 160 may be arranged so as not to overlap with the partition sealing portion 150 at all.

[0064] On the other hand, if the length of the additional sealing portion 160 is E, the length of the pouch-type outer packaging material 110 is L, and the radius (R) of the curved portion 163 of the additional sealing portion 160 is R, then the condition 0.06*L-2*R≦E≦0.06*L may be satisfied. The length (E) of the additional sealing portion 160 can be defined in the direction of extension of the additional sealing portion 160 (see the vertical direction in Figure 5). The length (E) of the additional sealing portion 160 can be measured on the side adjacent to the compartment sealing portion 150. The length (L) of the pouch-type outer packaging material 110 can be defined in the direction corresponding to the direction of extension of the additional sealing portion 160. In Figure 5, the length of the pouch-type outer packaging material 110 can be defined in the vertical direction, which is the direction in which the electrode lead 141 is exposed.

[0065] To suppress deformation of the containment section 111, a longer additional sealing section 160 is advantageous. However, if the additional sealing section 160 is very long, it may hinder the movement of gas generated during the activation process from the containment section 111 to the collection section 112. The length of the additional sealing section 160 can be determined considering these points. If the length of the additional sealing section 160 is less than "0.06*L-2*R", the effect of suppressing deformation of the containment section 111 may be hindered. If the length of the additional sealing section 160 is greater than "0.06*L", the movement of gas to the collection section 112 may be hindered.

[0066] secondary battery By manufacturing a secondary battery through the process described above, a secondary battery (intermediate product) like the one shown in Figure 5 can be produced. The secondary battery in Figure 5 may include a pouch-type outer casing 110 having a housing section 111 and a collection section 112, a peripheral sealing section 130 that seals the periphery of the pouch-type outer casing 110, a compartment sealing section 150 that seals the space between the housing section 111 and the collection section 112 within the pouch-type outer casing 110, and an additional sealing section 160 that seals a predetermined area of ​​the collection section 112 within the pouch-type outer casing 110. The additional sealing section 160 may extend in a direction corresponding to the extension direction of the compartment sealing section 150 at the peripheral sealing section 130 and be positioned at a distance from the compartment sealing section 150. The portion of the pouch-type outer casing 110 located on the collection section 112 side of the compartment sealing section 150 may be removed after the degassing process. This allows for the production of a secondary battery (final product) like the one shown in Figure 6.

[0067] Example 2 Figure 8 is a plan view illustrating the secondary battery (intermediate product) according to Example 2 of this document. The secondary battery according to this example differs from the secondary battery of Example 1 in the shape of the peripheral sealing portion, and this will be the main focus of the explanation below. For reference, the contents of Example 2 may also be applied to the previously described examples, as long as they do not contradict each other.

[0068] The secondary battery according to this embodiment includes a linearly formed peripheral sealing portion 230, as shown in Figure 8. The upper and lower peripheral sealing portions 231 and 232 in Figure 8 may be formed linearly in a direction perpendicular to the vertical direction, which is the direction in which the electrode leads 141 are exposed. The right peripheral sealing portion 233 may be formed linearly in the vertical direction.

[0069] The method for manufacturing the secondary battery in Example 1 may be applied regardless of the shape of the peripheral sealing portion. For example, the manufacturing method in Example 1 may also be applied to the process of manufacturing the secondary battery shown in Figure 8.

[0070] The above description is merely illustrative of the technical concept of the present invention, and a person with ordinary skill in the art to which the present invention belongs can make various modifications and alterations without departing from the essential characteristics of the present invention.

[0071] Therefore, the embodiments disclosed in this invention are for illustrative purposes only, and not to limit the technical concept of the invention, and the scope of the technical concept of the invention is not limited by such embodiments.

[0072] The scope of protection of this invention shall be interpreted in accordance with the following claims, and all technical concepts within an equivalent scope shall be interpreted as being included within the scope of the rights of this invention. [Explanation of Symbols]

[0073] 1. Pouch-type rechargeable battery 2 electrode assembly 15 Electrode Tabs 17 Electrode Leads 20 Pouch-type exterior materials 21 Storage Unit 23 Sealing section 110 Pouch-type exterior material 111 Detention Unit 112 Collection section 113a Upper peripheral portion 113b Lower peripheral portion 113c Right side peripheral part 113d Left peripheral area 120 Exterior Material Sheet 121 Metal layer 122, 123 Resin layer 131 Upper peripheral sealing portion 131a 1st horizontal section 131b 1st extension 131b1 Inclined extension 131b2 Horizontal extension 131c 2nd extension 131d 2nd horizontal section 131e 3rd extension 132 Lower peripheral sealing portion 133 Right side peripheral sealing part 140 Electrode assembly 141 Electrode Leads 150 Compartment sealing section 151 Sealing part 152 Temporary attachment part 153 Unsealed portion 160 Additional sealing section 161 Upper additional sealing part 162 Bottom additional sealing part 163 Curved section 230 Peripheral sealing portion 231 Upper peripheral sealing portion 232 Lower peripheral sealing portion 233 Right side peripheral sealing part

Claims

1. A first sealing step involves sealing the periphery of a pouch-type outer packaging material by forming a peripheral sealing portion on the periphery of the pouch-type outer packaging material, which has a housing portion for housing an electrode assembly and a collection portion for collecting gas generated during the charging and discharging process of the electrode assembly. A degassing step in which the gas collected in the collection section during the charging and discharging process of the electrode assembly is discharged to the outside of the pouch-type outer material, The second sealing step includes forming a partition sealing portion between the housing portion and the collection portion in the pouch-type outer material in order to separate the housing portion from the collection portion after the degassing step, The first sealing step is, A method for manufacturing a secondary battery, comprising the step of further forming an additional sealing portion that extends in a direction traversing the space between the housing portion and the collection portion at the peripheral sealing portion and is positioned on the collection portion side, separated from the compartment sealing portion.

2. The aforementioned additional sealing portion is A method for manufacturing a secondary battery according to claim 1, wherein the battery is arranged so as not to overlap with the compartment sealing portion.

3. The aforementioned additional sealing portion is A method for manufacturing a secondary battery according to claim 1, comprising a curved portion that extends from the peripheral sealing portion and is formed by recessing in a curved shape defined by a predetermined radius from a predetermined point in the pouch-type outer material that is separated from the additional sealing portion toward the housing portion.

4. The separation distance between the additional sealing portion and the partition sealing portion is, The method for manufacturing a secondary battery according to claim 3, wherein the curved portion is in a direction perpendicular to the extension direction of the partition sealing portion, and is at least half of the radius of the curved portion and less than or equal to the radius.

5. A method for manufacturing a secondary battery according to claim 3, wherein E is the length of the additional sealing portion defined in the extension direction of the additional sealing portion, L is the length of the pouch-type outer material defined in the direction corresponding to the extension direction of the additional sealing portion, and R is the radius of the curved portion, and the condition 0.06 * L - 2 * R ≤ E ≤ 0.06 * L is satisfied.

6. The aforementioned peripheral sealing portion is A first horizontal portion is provided on the side from which the electrode leads electrically connected to the electrode assembly are drawn out, and is formed in a horizontal direction perpendicular to the direction in which the electrode leads are drawn out. A first extension extends from one end of the first horizontal section that is adjacent to the collection section, in a direction away from the first horizontal section, until it exceeds the housing section, A second extension extends from the end of the first extension, inclined outward toward the pouch-type exterior material in a direction horizontally away from the first extension, A method for manufacturing a secondary battery according to claim 1, comprising: a second horizontal portion extending from the end of the second extension portion in a direction horizontally away from the second extension portion.

7. The first extension is, An inclined extension portion extends from one end of the first horizontal portion, inclined toward the inside of the pouch-type exterior material in a direction horizontally away from the first horizontal portion, A method for manufacturing a secondary battery according to claim 6, comprising: a horizontal extension extending from the end of the inclined extension in a direction horizontally away from the inclined extension.

8. The aforementioned peripheral sealing portion is The method for manufacturing a secondary battery according to claim 6, further comprising a third extension portion that extends from the other end of the first horizontal portion that is located further away from the collection portion, inclined toward the inside of the pouch-type outer material in a direction horizontally away from the first horizontal portion.

9. The connection point between the additional sealing portion and the peripheral sealing portion is, A method for manufacturing a secondary battery according to claim 6, wherein the battery is located within the first extension and the second extension.

10. A pouch-type outer material comprising a housing section for housing an electrode assembly and a collection section for collecting gas generated during the charging and discharging process of the electrode assembly, A peripheral sealing portion that seals the periphery of the pouch-type outer material, The pouch-type outer packaging includes a partition sealing portion that seals the space between the housing portion and the collection portion, thereby separating the housing portion from the collection portion. The pouch-type outer packaging material includes an additional sealing portion that seals a predetermined area of ​​the collection portion, The aforementioned additional sealing portion is A secondary battery having a peripheral sealing portion that extends in a direction corresponding to the extension direction of the partition sealing portion and is positioned at a distance from the partition sealing portion.

11. The aforementioned additional sealing portion is The secondary battery according to claim 10, which is arranged so as not to overlap with the compartment sealing portion.

12. The aforementioned additional sealing portion is The secondary battery according to claim 10, which includes a curved portion that extends from the peripheral sealing portion and is formed by recessing in a curved shape defined by a predetermined radius from a predetermined point in the pouch-type outer material that is separated from the additional sealing portion toward the housing portion.

13. The separation distance between the additional sealing portion and the partition sealing portion is, The secondary battery according to claim 12, wherein the curved portion is in a direction perpendicular to the extension direction of the partition sealing portion, and is equal to or less than half of the radius of the curved portion and less than or equal to the radius.

14. The secondary battery according to claim 12, wherein E is the length of the additional sealing portion defined in the extension direction from the peripheral sealing portion to the additional sealing portion, L is the length of the pouch-type outer material defined in the direction corresponding to the extension direction of the additional sealing portion, and R is the radius of the curved portion, and the condition 0.06*L - 2*R ≤ E ≤ 0.06*L is satisfied.

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