Sealing apparatus for pouch type secondary battery

Abstract

The sealing device for a pouch-type secondary battery according to the present invention is a sealing device for sealing a pouch outer material of a pouch-type secondary battery by heat-pressing, comprising: an upper sealing body that applies heat and pressure to the upper surface of the pouch; an upper sealing block coupled to the upper sealing body and contacting the pouch to seal the pouch; a lower sealing body that applies heat and pressure to the lower surface of the pouch; and a lower sealing block coupled to the lower sealing body and contacting the pouch to seal the pouch, wherein the upper sealing block may have an upper protruding rib formed on its lower surface having a length shorter than the length of the side sealing portion of the pouch.

Description

Technology Field

[0001] The present invention relates to a sealing device for a pouch-type secondary battery, and more specifically, to a sealing device for a pouch-type secondary battery that can prevent insulation failure from occurring due to excessive sealing of the area where the top sealing part and the side sealing part of the pouch overlap. Background Technology

[0003] With the recent advancement of electronic technology, the demand for secondary batteries used in electronic devices such as mobile phones, camcorders, and laptop computers is increasing. Furthermore, due to stricter environmental regulations in the global automotive market, persistently high oil prices, and the depletion of fossil fuels, the demand for secondary batteries for automobiles is also rising.

[0004] Looking at the manufacturing process of such secondary batteries, first, a charge-discharge step is performed in which the electrode assembly is inserted into a pouch and activated through charge-discharge cycles. Next, a degassing step is performed to remove gas generated inside the pouch during the charge-discharge step. The degassing step involves opening a portion of the pouch's rim to form an opening, and then using a vacuum to expel the gas inside the pouch through this opening. Next, a sealing step is performed to re-seal the opening and seal the pouch. Subsequently, the process may proceed through a trimming step to cut the opening, a side folding step to smooth the cut surface, and a hot pressing step to adjust the battery thickness.

[0005] When sealing a pouch, the side with the electrode is called the top sealing section, and the side with the electrode is called the side sealing section. Generally, the side sealing section is formed to be longer than the top sealing section. Additionally, the pouch sheet is typically composed of an innermost layer, a barrier layer, and an outermost layer; the innermost and outermost layers are made of insulating materials, and the barrier layer may be made of aluminum.

[0006] However, conventional sealing devices use a sealing block with a length longer than the length of the side sealing section to sequentially seal the top sealing section and the side sealing section, but there was a problem in that the area where the top sealing section and the side sealing section overlap was excessively sealed, causing frequent insulation failures. Prior art literature

[0008] Published Patent Application No. 10-2015-0072018 The problem to be solved

[0009] The present invention aims to provide a sealing device for a pouch-type secondary battery that can prevent insulation failure caused by excessive sealing of the area where the top sealing part and the side sealing part of the pouch overlap, by forming a protruding rib having a shorter length than the side sealing part of the pouch at the pouch contact part of the sealing block. means of solving the problem

[0011] The sealing device for a pouch-type secondary battery according to the present invention for achieving the above objective comprises: an upper sealing body that applies heat and pressure to the upper surface of the pouch; an upper sealing block coupled to the upper sealing body and in contact with the pouch to seal the pouch; a lower sealing body that applies heat and pressure to the lower surface of the pouch; and a lower sealing block coupled to the lower sealing body and in contact with the pouch to seal the pouch, wherein the upper sealing block may have an upper protruding rib formed on its lower surface having a length shorter than the length of the side sealing portion of the pouch.

[0012] The upper protruding rib can be formed to have a width of 40 to 60% of the width of the lower surface from one end of the width direction of the lower surface of the upper sealing block.

[0013] The above upper protruding rib may be formed such that both ends in the longitudinal direction are spaced 3 to 7 mm apart from the longitudinal end of the upper sealing block.

[0014] The above upper protruding rib may be formed with a protruding height in the range of 1 to 5% of the pouch thickness.

[0015] The lower sealing block may have a lower protruding rib formed on its lower surface having a length shorter than the length of the side sealing portion of the pouch.

[0016] The above lower protruding rib may be formed such that both ends in the longitudinal direction are spaced 3 to 7 mm apart from the longitudinal end of the lower sealing block.

[0017] The above lower protruding rib may be formed with a protruding height in the range of 1 to 5% of the pouch thickness.

[0018] The above sealing device can seal the side sealing portion of a double-sided forming bidirectional battery in which grooves of the electrode assembly are formed on the upper and lower sides of the pouch and a pair of electrodes are arranged on both sides.

[0019] The above sealing device may also seal the side sealing portion of a single-sided forming bidirectional battery in which a groove of the electrode assembly is formed on the upper side of the pouch and a pair of electrodes are arranged on both sides.

[0020] The above sealing device may also seal the side sealing portion of a double-sided forming unidirectional battery in which grooves of an electrode assembly are formed on the upper and lower sides of a pouch and a pair of electrodes are arranged on one side. Effects of the invention

[0022] According to the sealing device for a pouch-type secondary battery of the present invention described above, by forming a protruding rib having a shorter length than the side sealing portion of the pouch at the pouch contact portion of the sealing block, it is possible to prevent insulation failure from occurring due to excessive sealing of the area where the top sealing portion and the side sealing portion of the pouch overlap. Brief explanation of the drawing

[0024] FIG. 1 is a diagram showing the process of manufacturing a pouch-type secondary battery according to one embodiment of the present invention. FIG. 2 is a plan view showing a thermal compression portion of a pouch in a pouch-type secondary battery according to one embodiment of the present invention. FIG. 3 is a perspective view showing a sealing device for a pouch-type secondary battery according to one embodiment of the present invention. FIG. 4 is a bottom view (a) and a front view (b) showing an upper sealing block according to one embodiment of the present invention. FIG. 5 is a cross-sectional view schematically showing a sealing device for a pouch-type secondary battery according to the first embodiment of the present invention. FIG. 6 is a cross-sectional view schematically showing a sealing device for a pouch-type secondary battery according to a second embodiment of the present invention. Specific details for implementing the invention

[0025] The present invention is capable of various modifications and may have various embodiments, and specific embodiments are illustrated and described in detail in the detailed description. However, this is not intended to limit the present invention to specific embodiments, and it should be understood that it includes all modifications, equivalents, and substitutions that fall within the spirit and scope of the invention.

[0026] The terms used in this invention are used merely to describe specific embodiments and are not intended to limit the invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this invention, terms such as "comprising" or "having" are intended to indicate the existence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0027] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Note that in the accompanying drawings, identical components are indicated by the same reference numerals whenever possible. Furthermore, detailed descriptions of known functions and configurations that may obscure the essence of the present invention will be omitted. For the same reason, some components in the accompanying drawings may be exaggerated, omitted, or schematically depicted.

[0028] FIG. 1 is a drawing showing the process of manufacturing a pouch-type secondary battery according to one embodiment of the present invention, and FIG. 2 is a plan view showing the heat-compressed portion of the pouch in a pouch-type secondary battery according to one embodiment of the present invention.

[0029] First, the process of manufacturing a pouch-type secondary battery is explained with reference to Fig. 1.

[0030] As illustrated in FIG. 1(a), a pouch (111) is formed to create one or more grooves into which an electrode assembly (113) is received. The pouch can typically be manufactured by forming a sheet in which an innermost layer, a barrier layer, and an outermost layer are laminated. The innermost layer and the outermost layer may be made of an insulating material, and the barrier layer may be made of an aluminum material.

[0031] As shown in FIG. 1(b), a stack cell, i.e., an electrode assembly (113), is manufactured by stacking a positive electrode, a separator, and a negative electrode and housing them in a battery case, and can be inserted into a groove formed in a pouch (111). Positive terminals and negative terminals may protrude from both ends of the electrode assembly (113).

[0032] As shown in FIG. 1(c), the pouch (111) is folded so that the groove of the pouch (111) on which the electrode assembly (113) is not seated is seated on the upper half of the electrode assembly (113).

[0033] As illustrated in FIG. 1(d), a pouch-type secondary battery (110) can be manufactured by sealing three side portions along the edge of the pouch (111) by heat-pressing them with a sealing device. At this time, the pouch (111) is sealed while electrode leads (118) are connected to the positive terminal and negative terminal of the electrode assembly (113), respectively. The heat-pressing portion (115), which is the heat-pressing portion of the pouch (111), includes a top sealing portion on the short side where the electrode leads (118) are located and a side sealing portion on the long side.

[0034] Additionally, the heat-pressed portion (115) includes not only the portions near the three edges of the pouch (111) but also one side portion of the electrode assembly (113). The latter side sealing portion can be sealed after a degassing step to remove gas generated inside the pouch during the charging and discharging step.

[0035] As shown in FIG. 2, the side sealing portion, which is a portion of the heat-pressed portion (115) that is close to the side of the electrode assembly (113), may be formed in two places in the middle of the pouch (111). The portion of the pouch (111) where the electrode assembly (113) is not located may be cut off after sealing as a place for degassing.

[0036] However, the over-sealing area (116), which is the area where the top sealing part and the side sealing part overlap, is double-sealed before and after degassing, so it is highly likely to be over-sealed, causing insulation failure of the pouch. To prevent such over-sealing, the sealing device of the present invention can prevent the sealing block from double-sealing the over-sealing area (116).

[0037] FIG. 3 is a perspective view showing a sealing device for a pouch-type secondary battery according to one embodiment of the present invention, and FIG. 4 is a bottom view (a) and a front view (b) showing an upper sealing block according to one embodiment of the present invention.

[0038] As illustrated in FIG. 3, a sealing device for a pouch-type secondary battery according to one embodiment of the present invention comprises an upper sealing body (140) that applies heat and pressure to the upper surface of the pouch, an upper sealing block (130) that is coupled to the upper sealing body and contacts the pouch to seal the pouch, a lower sealing body (160) that applies heat and pressure to the lower surface of the pouch, and a lower sealing block (150) that is coupled to the lower sealing body and contacts the pouch to seal the pouch, wherein the upper sealing block (130) has an upper protruding rib (135) formed on its lower surface having a length shorter than the length of the side sealing portion of the pouch.

[0039] The upper sealing body (140) may have a rectangular shape and be configured to apply heat and pressure to the upper surface of the pouch. The upper sealing body (140) may be raised and lowered by an upper lifting frame (145) connected to its upper surface to press the upper surface of the pouch, and heat may be transferred to the pouch through a thermal fluid channel formed inside the upper sealing body (140).

[0040] The upper sealing block (130) may have a rectangular bar shape and be coupled to the upper sealing body (140). To this end, as shown in FIG. 4, a plurality of fastening holes (132) may be formed through the upper sealing block (130). A thermal fluid channel may also be formed inside the upper sealing block (130), or the upper sealing block (130) may be made of a thermally conductive material to transfer heat from the upper sealing body (140) to the pouch by conduction.

[0041] The lower sealing body (160) is installed so as to be vertically symmetric with the upper sealing body (140), and the lower lifting frame (165) is connected to the lower surface so that it can be lifted and compressed while applying heat and pressure to the lower surface of the pouch.

[0042] The lower sealing block (150) is coupled to the upper surface of the lower sealing body (160) so as to be symmetrical with the upper sealing block (130), and can be heat-pressed by contacting the lower surface of the pouch.

[0043] An upper protruding rib (135) is formed on the lower surface of the upper sealing block (130) so that the side sealing portion of the pouch can be heat-pressed. The upper protruding rib (135) has a length shorter than the length of the side sealing portion of the pouch, so that the over-sealing portion (116) where the top sealing portion and the side sealing portion overlap is not heat-pressed twice.

[0044] The upper protruding rib (135) can be formed to have a width of 40 to 60% of the width of the lower surface from one end of the width direction of the lower surface of the upper sealing block (130). Since the side sealing portion is positioned close to the long side of the electrode assembly housed in the pouch, the upper sealing block (130) can be formed from one end of the electrode assembly side of the long side of the lower surface of the upper protruding rib (135) in the width direction to approximately half of the width direction.

[0045] The upper protruding rib (135) can be formed such that both longitudinal ends are spaced 3 to 7 mm apart from the longitudinal ends of the upper sealing block (130). That is, the upper protruding rib (135) can be formed in the longitudinal middle of the upper sealing block (130) and spaced 3 to 7 mm apart from both ends. In this way, since the two ends of the upper protruding rib (135) do not seal the aforementioned over-sealing portion (116), it is possible to prevent the over-sealing portion (116) from being double-heat-pressed.

[0046] The upper protruding rib (135) may be formed with a protruding height in the range of 1 to 5% of the thickness of the pouch (111). Here, the thickness of the pouch (111) refers to the maximum thickness of the portion in which the electrode assembly (113) is housed. It is preferable that the upper protruding rib (135) be formed with a thermally conductive material so as not to be too thick so that heat can be transferred by conduction.

[0047] FIG. 5 is a cross-sectional view schematically showing a sealing device for a pouch-type secondary battery according to a first embodiment of the present invention, and FIG. 6 is a cross-sectional view schematically showing a sealing device for a pouch-type secondary battery according to a second embodiment of the present invention.

[0048] As illustrated in FIG. 5, the sealing device (100) according to the first embodiment is provided with an upper protruding rib (135) on the upper sealing block (130), and the lower sealing block (150) is not provided with a lower protruding rib, and the upper surface of the lower sealing block (150) can be heat-pressed by directly contacting the lower surface of the pouch (111).

[0049] As illustrated in FIG. 6, a lower protruding rib (155) having a length shorter than the length of the side sealing portion of the pouch may also be formed on the lower sealing block (150). In this case, the lower protruding rib (155) may be formed in a shape corresponding to a position facing the upper protruding rib (135).

[0050] That is, the lower protruding rib (155) can be formed such that both longitudinal ends are spaced 3 to 7 mm apart from the longitudinal end of the lower sealing block.

[0051] Additionally, the lower protruding rib (155) may be formed with a protruding height in the range of 1 to 5% of the pouch thickness.

[0052] The sealing device (100) of the pouch-type secondary battery of the present invention can seal the side sealing portion of a double-sided forming bidirectional battery in which a groove of an electrode assembly (113) is formed on the upper and lower sides of the pouch (111) as shown in FIG. 1 and a pair of electrodes are arranged on both sides.

[0053] The pouch (111) may be formed by stacking two sheets to cover the upper and lower surfaces of the electrode assembly (113), and then sealing two top sealing portions and two side sealing portions. That is, the four sides of the pouch (111) are sealed.

[0054] On the other hand, in the case of the pouch illustrated in FIG. 1, one pouch (111) sheet may be folded in half and stacked to cover the upper and lower surfaces of the electrode assembly (113), and then two top sealing portions and one side sealing portion may be sealed. In this case, three sides of the pouch (111) are sealed.

[0055] Additionally, the groove formed in the pouch (111) may be formed as a single groove only on the upper side of the electrode assembly (113) to accommodate the entire thickness of the electrode assembly (113), or two grooves may be formed on the upper side and lower side of the electrode assembly (113) to accommodate the upper and lower halves of the electrode assembly (113), respectively. If there are two grooves formed in the pouch (111), it becomes a double-sided forming battery, and if there is only one groove, it becomes a single-sided forming battery.

[0056] Additionally, a pair of electrode leads (118) of the electrode assembly (113) may be arranged one on each side of the electrode assembly (113), or two may be arranged side by side on one side of the electrode assembly (113). When a pair of electrode leads (118) are arranged on both sides, it becomes a bidirectional battery, and when two are arranged on one side, it becomes a unidirectional battery.

[0057] The sealing device (100) of the present invention can seal the side sealing portion of a double-sided forming bidirectional battery as shown in FIG. 1.

[0058] The sealing device (100) of the present invention may also seal the side sealing portion of a single-sided forming bidirectional battery in which a groove of an electrode assembly (113) is formed on the upper side of a pouch (111) and a pair of electrodes are arranged on both sides.

[0059] The sealing device (100) of the present invention may seal the side sealing portion of a double-sided forming unidirectional battery in which grooves of an electrode assembly (113) are formed on the upper and lower sides of a pouch (111) and a pair of electrodes are arranged on one side.

[0060] According to the sealing device for a pouch-type secondary battery of the present invention, by forming a protruding rib having a shorter length than the side sealing portion of the pouch at the pouch contact portion of the sealing block, it is possible to prevent insulation failure caused by excessive sealing of the area where the top sealing portion and the side sealing portion of the pouch overlap.

[0062] Although an embodiment of the present invention has been described above, those skilled in the art may modify and change the present invention in various ways by adding, changing, deleting, or adding components, etc., without departing from the spirit of the present invention as described in the claims, and such modifications and changes are also to be considered to be included within the scope of the rights of the present invention. Explanation of the symbols

[0064] 100: Sealing device for pouch-type secondary batteries 110: Pouch-type secondary battery 111: Pouch 113: Electrode assembly 115: Hot-pressed section 116: Fruit sealing area 118: Electrode Lead 130: Upper sealing block 132: Fastener 135: Upper protruding rib 140: Upper sealing body 145: Upper lifting frame 150: Lower sealing block 155: Lower protruding rib 160: Lower sealing body 165: Lower lifting frame

Claims

Claim 1 A sealing device for sealing a pouch outer material of a pouch-type secondary battery by heat-pressing, comprising: an upper sealing body that applies heat and pressure to the upper surface of the pouch; an upper sealing block coupled to the upper sealing body and contacting the pouch to seal the pouch; a lower sealing body that applies heat and pressure to the lower surface of the pouch; and a lower sealing block coupled to the lower sealing body and contacting the pouch to seal the pouch, wherein the upper sealing block has an upper protruding rib formed on its lower surface having a length shorter than the length of the side sealing portion of the pouch, and the upper protruding rib is formed such that both ends in the longitudinal direction are spaced 3 to 7 mm apart from the end in the longitudinal direction of the upper sealing block. Claim 2 A sealing device for a pouch-type secondary battery according to claim 1, characterized in that the upper protruding rib is formed to have a width of 40 to 60% of the width of the lower surface from one end of the width direction of the lower surface of the upper sealing block. Claim 3 delete Claim 4 A sealing device for a pouch-type secondary battery according to claim 2, characterized in that the upper protruding rib is formed with a protruding height in the range of 1 to 5% of the pouch thickness. Claim 5 A sealing device for a pouch-type secondary battery according to claim 1, wherein the lower sealing block has a lower protruding rib formed on its lower surface having a length shorter than the length of the side sealing portion of the pouch. Claim 6 A sealing device for a pouch-type secondary battery according to claim 5, characterized in that the lower protruding rib is formed such that both longitudinal ends thereof are spaced 3 to 7 mm apart from the longitudinal end of the lower sealing block. Claim 7 A sealing device for a pouch-type secondary battery according to claim 5, characterized in that the lower protruding rib is formed with a protruding height in the range of 1 to 5% of the pouch thickness. Claim 8 A sealing device for a pouch-type secondary battery according to claim 1, wherein the sealing device seals the side sealing portion of a double-sided forming bidirectional battery in which a groove of an electrode assembly is formed on the upper and lower sides of the pouch and a pair of electrodes are arranged on both sides. Claim 9 A sealing device for a pouch-type secondary battery according to claim 1, wherein the sealing device seals the side sealing portion of a single-sided forming bidirectional battery in which a groove of an electrode assembly is formed on the upper side of the pouch and a pair of electrodes are arranged on both sides. Claim 10 A sealing device for a pouch-type secondary battery according to claim 1, wherein the sealing device seals a side sealing portion of a double-sided forming unidirectional battery in which a groove of an electrode assembly is formed on the upper and lower sides of the pouch and a pair of electrodes are disposed on one side.

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