Pouch cell and pouch cell assembly comprising same

Abstract

According to exemplary embodiments, a pouch cell is provided. The pouch cell comprises: an electrode assembly including a separator between a positive electrode and a negative electrode; a pouch surrounding the electrode assembly and accommodating the electrode assembly; and an exterior cover surrounding the outside of the pouch, wherein a hinged venting part may be formed on the exterior cover.

Description

Pouch cell and pouch cell assembly including the same

[0001] The present invention relates to a pouch cell and a pouch cell assembly including the same, and specifically, to a pouch cell capable of inducing venting in a specific direction and a pouch cell assembly in which such pouch cells are arranged.

[0002] The present disclosure claims the benefit of priority based on Korean Patent Application No. 10-2025-0022876 filed on February 21, 2025, and all contents of Korean Patent Application No. 10-2025-0022876 are incorporated by reference into the present disclosure.

[0003] With the significant increase in technological development and demand for various mobile devices, electric vehicles, and energy storage systems, interest and demand for secondary batteries as an energy source are rapidly growing.

[0004] As a representative secondary battery, lithium-ion batteries are widely used because they allow for free charging and discharging, have a very low self-discharge rate, and high energy density.

[0005] A lithium secondary battery consists of an electrode assembly in which a positive plate and a negative plate, each coated with a positive active material and a negative active material respectively, are arranged with a separator in between, and a battery case that seals and houses the electrode assembly together with an electrolyte.

[0006] Secondary batteries can be classified according to the shape of the battery case into can-type batteries, in which the electrode assembly is embedded in a metal can, and pouch-type batteries, in which the electrode assembly is embedded in a pouch made of aluminum laminate sheets. Pouch-type batteries (hereinafter also referred to as pouch cells) are attracting significant attention due to their low manufacturing cost, small weight, and easy shape deformation, and their usage is gradually increasing.

[0007] However, the electrolyte in pouch cells can decompose due to factors such as overcharging, exposure to high temperatures, and internal short circuits. Consequently, a large amount of gas may be generated internally, and swelling may occur, causing the pouch of the pouch cell to bulge. Swelling can induce high pressure inside the sealed pouch and further accelerate the decomposition of the electrolyte, potentially leading to the explosion of the pouch cell. Additionally, the central part of the pouch may bulge due to the gas, causing deformation of the cell and even leading to an electrical short circuit. Furthermore, because pouch cells are densely packed into the confined spaces of battery modules or battery packs to increase energy density, it is necessary to precisely control the direction of discharge for high-temperature gases or flames generated from each pouch cell.

[0008] However, in the case of conventional pouch cells, although venting guides were provided by weakening specific areas of the pouch, gas generated inside the pouch would often vent in various directions, including not only the sealing or folding areas but also the sides of the pouch cell. As a result, during actual application, the sealing performance of the pouch cell was compromised, and the direction of gas discharge could not be accurately controlled.

[0009] The objective of the present invention is to provide a pouch cell capable of precisely controlling the direction of gas discharge from the pouch cell unit when swelling or thermal runaway occurs in the pouch cell.

[0010] In addition, another objective of the present invention is to provide a pouch cell assembly comprising such a pouch cell.

[0011] According to exemplary embodiments of the present invention for solving the above-described problem, a pouch cell is provided. The pouch cell comprises: an electrode assembly including a separator between a positive electrode and a negative electrode; a pouch surrounding the electrode assembly and accommodating the electrode assembly; and an outer cover surrounding the outside of the pouch. A hinged venting part is formed in the outer cover.

[0012] In the above pouch cell, the area of ​​the pouch corresponding to the hinge venting portion may be thinner than the remaining area of ​​the pouch.

[0013] The hinge venting portion can be opened when the internal pressure of the pouch exceeds a certain pressure.

[0014] The hinge venting portion can be opened within a certain angle range so that the venting channel is limited in a certain direction. Preferably, the hinge venting portion can be opened at an angle ranging from 5° to 80°.

[0015] The hinge venting portion has a square shape, and the hinge venting portion can be opened by using the one side as a hinge axis so that one side of the hinge venting portion is integrally formed with the outer cover and the remaining sides are cut.

[0016] In addition, the hinge venting portion has a semicircular shape, and the semicircular diameter of the hinge venting portion is integrally formed with the outer cover, and the remaining arc section is cut so that the hinge venting portion can be opened.

[0017] In addition, the hinge venting portion has an elliptical shape, and a portion of the arc section of the hinge venting portion is integrally formed with the outer cover, while the remaining arc section is cut so that the hinge venting portion can be opened.

[0018] The hinge venting portion may be formed in at least one or more places in the folding area of ​​the exterior cover.

[0019] The above exterior cover may be composed of FRB (Flame Resistance Barrier) or NCG (Non-Combustible Glassfiber) refractory materials.

[0020] Meanwhile, according to exemplary embodiments of the present invention, a pouch cell assembly is provided. The pouch cell assembly comprises a plurality of pouch cells, and the plurality of pouch cells may be arranged such that their respective hinge venting portions are aligned in a certain direction.

[0021] Insulating pads may be further arranged between the plurality of pouch cells mentioned above.

[0022] According to one embodiment of the present invention, by providing an outer cover on the outside of a pouch and a hinge venting portion on the outer cover, the direction of gas discharge can be precisely controlled from the pouch cell unit. Accordingly, swelling of the pouch cell or thermal runaway can be prevented.

[0023] The effects obtainable from the exemplary embodiments of the present invention are not limited to those mentioned above, and other unmentioned effects can be clearly derived and understood by those skilled in the art to which the exemplary embodiments of the present disclosure belong from the following description. That is, unintended effects resulting from the implementation of the exemplary embodiments of the present disclosure can also be derived by those skilled in the art from the exemplary embodiments of the present disclosure.

[0024] FIG. 1 is a perspective view of a pouch cell according to one embodiment.

[0025] Figure 2 is a side view of Figure 1.

[0026] Figure 3 is a detailed view of part A of Figure 1.

[0027] FIG. 4 is a schematic diagram illustrating the operation of the hinge venting portion of the pouch cell of FIG. 1.

[0028] Figures 5a and 5b are example diagrams of the hinge venting portion of different pouch cells.

[0029] FIG. 6 is a perspective view of another pouch cell according to one embodiment.

[0030] FIG. 7 is a perspective view of a pouch cell assembly in which the pouch cells of FIG. 1 are arranged.

[0031] Figure 8 is a schematic diagram of the BB line cross-section of Figure 7.

[0032] FIG. 9 is a cross-sectional schematic diagram for explaining the operation of a pouch cell assembly equipped with the pouch cell of FIG. 8.

[0033] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. Prior to this, terms and words used in this specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings. Instead, based on the principle that the inventor can appropriately define the concepts of terms to best describe his invention, they should be interpreted in a meaning and concept consistent with the technical spirit of the present invention.

[0034] Therefore, the embodiments described in this specification and the configurations illustrated in the drawings are merely the most preferred embodiments of the present invention and do not represent all of the technical ideas of the present invention; thus, it should be understood that various equivalents and modifications that can replace them may exist at the time of filing this application.

[0035] In addition, in describing the present invention, if it is determined that a detailed description of related known components or functions may obscure the essence of the invention, such detailed description is omitted.

[0036] Since embodiments of the present invention are provided to more fully explain the invention to those skilled in the art, the shapes and sizes of the components in the drawings may be exaggerated, omitted, or schematically depicted for clearer explanation. Accordingly, the size or proportion of each component does not entirely reflect the actual size or proportion.

[0037]

[0038] (1st embodiment)

[0039] FIG. 1 is a perspective view of a pouch cell (100) according to one embodiment, FIG. 2 is a side view of FIG. 1, and FIG. 3 is a detailed view of part A of FIG. 1.

[0040] Referring to FIGS. 1 to 3, a pouch cell (100) according to one embodiment includes an electrode assembly (110), a pouch (120), and an electrode lead (130).

[0041] The electrode assembly (110) has a structure in which a positive electrode (131) and a negative electrode (132) are stacked with a separator in between. The positive electrode (131) or the negative electrode (132) of the electrode assembly (110) is connected to one end of the electrode lead (130), and the other end extends to the outside of the pouch (120) and can be located outside the pouch (120).

[0042] The pouch (120) has two pouch portions facing each other and is configured to accommodate an electrode assembly (110) and an electrolyte material in a receiving space provided between the two pouch portions.

[0043] Such a pouch (120) may be manufactured from a sheet of metal material including aluminum. In one embodiment, the pouch (120) may be manufactured from a single metal sheet. For example, the pouch (120) may be manufactured by folding the metal sheet so that both ends of the metal sheet face each other, and then sealing the edges of the overlapping ends by joining them together. In this case, the two pouch parts may be formed as a single unit.

[0044] In another embodiment, the pouch (120) may be manufactured from two metal sheets. For example, the pouch may be manufactured by overlapping two metal sheets so as to face each other and sealing the edges of the overlapping two metal sheets by joining them together. In this case, the two pouch portions may be composed of different metal sheets.

[0045] In another embodiment, the pouch (120) comprises an outer coating layer, a metal layer, and an inner adhesive layer, and, in some cases, may further comprise an adhesive layer between the outer coating layer and the metal layer, and between the metal layer and the inner adhesive layer.

[0046] Additionally, the mutually bonded edge portions of the pouch (120) may each have a PP (polypropylene) layer provided on the mutually contacting surface, and these PP layers may be sealed by heat fusion.

[0047] This pouch sealing process is difficult to perform uniformly due to various factors such as heating temperature, time, thickness, width, and quality of the PP layer. Therefore, it is difficult to consistently control the direction of the gas discharged through the sealed edge portion of the pouch cell (100).

[0048] When thermal runaway occurs in a pouch cell, if high-temperature gas or flames generated inside the pouch cell are released toward the sealing portion where the electrode lead is located, it may damage the terminal connected to the electrode lead or cause a chain reaction of thermal runaway in other surrounding pouch cells.

[0049] Meanwhile, the pouch cell (100) according to the present embodiment includes an outer cover (140) that surrounds the outside of the pouch (120), and a hinge venting portion (150) may be formed on the outer cover (140). Such a pouch cell (100) can control the direction of gas discharged through the hinge venting portion (150) at a constant level.

[0050] The outer cover (140) may be formed by joining two sheets together to wrap around the outside of the pouch (120) containing the electrode assembly (110). The outer cover (140) may be manufactured from a fireproof sheet having a certain degree of rigidity to have a certain structural shape. The outer cover (140) may be manufactured by folding the fireproof sheet so that both ends of the fireproof sheet face each other, and then joining and sealing the edges of the overlapping fireproof sheets. In this embodiment, the outer cover (140) may be composed of a flame resistance barrier (FRB) or non-combustible glass fiber (NCG) fireproof material.

[0051] The hinge venting portion (150) forms part of the outer cover (140) of the pouch (120) and can be configured to rupture before the outer cover (140) when the gas pressure of the pouch (120) increases. To this end, the hinge venting portion (150) may be configured to have a thinner thickness than other parts of the outer cover (140), or may be configured to have the same thickness as other parts but may have a line-shaped groove or notch. For convenience of explanation, in FIG. 3, the hinge venting portion (150) is shown with its upper surface partially cut and sealed.

[0052] The hinge venting portion (150) may be formed in the folding area (141) of the outer cover (140). In the pouch cell (100) according to the present embodiment, the folding area of ​​the pouch (120) corresponding to the hinge venting portion (150) may also be thinner than the remaining area of ​​the pouch (120).

[0053] In order to reduce the thickness of the hinge venting portion (150), the hinge venting portion (150) of the outer cover (140) can be punched repeatedly several times. The venting pressure of the hinge venting portion (150) is smaller than the venting pressure of the heat-sealed pouch (120). Therefore, when the internal pressure of the pouch cell (100) increases, the pouch (120) vents, and the hinge venting portion (150) can also be easily broken.

[0054] The hinge venting part (150) can be formed in any one of square, polygonal, semicircular, elliptical, and rhombus shapes, and can have various shapes.

[0055] When the hinge venting portion (150) has a square shape, the hinge venting portion (150) can be opened by using the one side as a hinge axis so that one side of the hinge venting portion (150) is integrally formed with the outer cover (140) and the remaining sides are cut.

[0056] FIG. 4 shows the operation of the hinge venting portion (150) of the pouch cell (100).

[0057] As illustrated in FIG. 4, the hinge venting portion (150) can be opened when the internal pressure of the pouch (120) exceeds a certain pressure. At this time, the hinge venting portion (150) can be opened to a certain angle (θ) range, thereby restricting the venting flow path of the pouch cell (100) in a certain direction. It is preferable that the hinge venting portion (150) be opened at an angle (θ) in the range of 5° to 80°. If the hinge venting portion (150) is opened at an angle (θ) of 5° or less, it is easy to directly affect adjacent cells, and if it is opened at an angle (θ) in the range of 80°, a venting flow path can be formed directly upward.

[0058] FIGS. 5A and 5B are exemplary diagrams of hinge venting portions (151, 152) of different pouch cells (100).

[0059] Referring to FIG. 5a, the pouch cell (100) may have a semicircular hinge venting portion (151). In this case, the hinge venting portion (151) may have a semicircular diameter that is integral with the outer cover (140), and the remaining arc portion may be cut so that the hinge venting portion (151) can be opened.

[0060] Referring to FIG. 5b, the pouch cell (100) may have an elliptical hinge venting portion (152). In this case, a portion of the arc of the hinge venting portion (152) may be integral with the outer cover (140), and the remaining arc portion may be cut to open the hinge venting portion (152).

[0061] FIG. 6 is a perspective view of another pouch cell (100') according to one embodiment.

[0062] Referring to FIG. 6, another pouch cell (100') has two hinge venting portions (150A, 150B) of the same shape formed in the folding area (141) of the outer cover (140). The hinge venting portions (150) may be formed with at least one of the same shape as needed, or multiple of different shapes.

[0063] In the case of the pouch cell (100) according to the present embodiment, an outer cover (140) is provided on the outside of the pouch (120), and if the gas discharge position and direction of the pouch cell (100) are controlled through a hinge venting part (140) installed in the folding area of ​​the outer cover (140), the gas can be discharged in an intended direction from the battery module or battery pack to which the pouch cell (100) is applied.

[0064] These pouch cells (100) may be composed of a plurality of them as described below, and the plurality of pouch cells (100) may be stacked so as to be electrically connected to each other to form a pouch cell assembly.

[0065]

[0066] (2nd Example)

[0067] FIG. 7 is a perspective view of a pouch cell assembly (200) in which the pouch cells (100) of FIG. 1 are arranged, and FIG. 8 is a schematic cross-sectional view along the BB line of FIG. 7.

[0068] Referring to the drawings, the pouch cell assembly (200) according to the present embodiment may have a plurality of pouch cells (100) arranged along the Z-axis direction (thickness direction of the pouch cells). For convenience of explanation, the length direction of the pouch cells (100) is defined as the X-axis direction, the width direction as the Y-axis direction, and the thickness direction as the Z-axis direction in this specification.

[0069] A pouch cell assembly (200) can be assembled by arranging a plurality of pouch cells (100) such that each hinge venting part (150) is aligned in a certain direction of the Z-axis, and surrounding the plurality of pouch cells (100) with a plurality of tapes (T).

[0070] The pouch cell assembly (200) may be accommodated in a battery pack and may consist of at least one other cell unit or cell block. In this case, each cell unit and cell block may be stacked side by side.

[0071] The pouch cell assembly (200) can be directly seated in a battery pack without a separate module frame, in a state where at least one pouch cell (100) is assembled in multiple numbers and assembled by a tape (T).

[0072] To this end, the battery pack may include walls constituting an internal space and cross beams dividing the internal space into a plurality of receiving rooms.

[0073] In one embodiment, a gas inlet is provided on one side of a wall adjacent to the internal space of a battery pack for gas generated from a cell unit to flow in, and a gas channel may be provided inside the wall. Additionally, a venting device may be provided on the other side of the wall adjacent to the outside for discharging gas moved through the gas channel to the outside.

[0074] In this case, the gas flow path leading to the gas inlet, gas channel, and venting device of the side wall may be provided individually for each receiving room.

[0075] In one embodiment, the battery pack may further include a heat sink (not shown). The heat sink may be interposed between the bottom surface of a receiving room on which a cell unit is seated and the cell unit. This heat sink may be configured to make thermal contact with the cell unit and to cool the cell unit. To this end, the heat sink may be made of a metal material with high thermal conductivity and heat resistance.

[0076] In one embodiment, an insulating pad may be further arranged between the plurality of pouch cells.

[0077] In addition, the battery pack can be configured to accommodate various additional electrical components as needed. For example, the battery pack can accommodate various electronic components (not shown) that control the charging and discharging operations of pouch cells included in each cell unit, or monitor the State of Charge (SOC), State of Health (SOH), etc.

[0078] The cell unit may include a busbar, a busbar frame, and an insulating cover.

[0079] The above busbar can be configured to be electrically connected to the electrode lead (130) of at least one pouch cell (100).

[0080] The busbar frame may be configured to support the busbar. Such a busbar frame may also be provided with a terminal electrically connected to the busbar.

[0081] The above insulating cover may be configured to prevent a short circuit of the electrode lead (130) or busbar. To this end, the insulating cover may be composed of an insulating polymer synthetic resin.

[0082] FIG. 9 is a cross-sectional schematic diagram for explaining the operation of a pouch cell assembly (200) equipped with the pouch cell (100) of FIG. 8.

[0083] FIGS. 8 and FIGS. 9 are schematic cross-sectional views of the BB line of FIG. 7, respectively, showing the state of the pouch cell assembly (200) before the event occurs and FIG. 9 after the event occurs. For convenience of explanation, FIGS. 8 and FIG. 9 only show three pouch cells (100A, 100B, 100C).

[0084] Referring to the drawing, when a large amount of gas is generated inside the pouch (120) due to factors such as overcharging, exposure to high temperature, or internal short circuit in the pouch cell (100B), the internal pressure of the pouch (120) increases, and gas or flames are generated inside the pouch (120). At this time, since there is an outer cover (140) on the outside of the pouch (120) and a hinge venting part (150) is provided on the upper part of the outer cover (140), even if the gas or flames inside the pouch (120) are ejected from any direction, the venting gas or flames can be guided in a specific direction as indicated by the arrow by the hinge venting part (150).

[0085] Therefore, even if pouch cells (100) are densely arranged in a narrow space of a battery module or battery pack, the direction of discharge of high-temperature gas or flame generated in each pouch cell (100) can be precisely controlled.

[0086] As described above, the pouch cell (100) according to the present invention packages an outer cover (140) in a pouch (120) and provides a hinge venting portion (150) in the folding area (141) of the outer cover (140), thereby allowing for precise control of the direction of gas discharge from the pouch cell unit, and thereby preventing swelling or thermal runaway of the pouch cell.

[0087] In addition, when a plurality of pouch cells (100) according to the present invention are mounted in a battery pack without a battery module or a separate module, it is easy to induce venting of high-temperature gas, etc. in a specific direction, thereby ensuring reliable protection of other pouch cells.

[0088] The present invention has been described in more detail above through drawings and embodiments. However, the configurations described in the drawings or embodiments described in this specification are merely one embodiment of the present invention and do not represent all technical concepts of the present invention; therefore, it should be understood that various equivalents and modifications that can replace them may exist at the time of filing this application.

Claims

1. An electrode assembly including a separator between an anode and a cathode; A pouch that encloses the electrode assembly and accommodates the electrode assembly; and Includes an outer cover surrounding the outside of the above pouch; A pouch cell having a hinged venting part formed on the outer cover.

2. In Paragraph 1, A pouch cell in which the area of ​​the pouch corresponding to the hinge venting portion is thinner than the remaining area of ​​the pouch.

3. In Paragraph 1, The above hinge venting portion is a pouch cell that opens when the internal pressure of the pouch exceeds a certain pressure.

4. In Paragraph 3, A pouch cell in which the hinge venting portion is opened within a certain angle range and the venting channel is limited in a certain direction.

5. In Paragraph 4, A pouch cell in which the above hinge venting portion opens at an angle ranging from 5° to 80°.

6. In Paragraph 1, A pouch cell in which the hinge venting portion has a square shape, and the hinge venting portion is opened using the one side as a hinge axis so that one side of the hinge venting portion is integrally formed with the outer cover and the remaining sides are cut.

7. In Paragraph 1, A pouch cell in which the hinge venting portion has a semicircular shape, the semicircular diameter of the hinge venting portion is integrally formed with the outer cover, and the remaining arc section is cut to open the hinge venting portion.

8. In Paragraph 1, A pouch cell in which the hinge venting portion has an elliptical shape, a portion of the arc section of the hinge venting portion is integrally formed with the outer cover, and the remaining arc section is cut so that the hinge venting portion is opened.

9. In Paragraph 1, The above hinge venting portion is a pouch cell formed in at least one of the folding areas of the exterior cover.

10. In Paragraph 1, The above outer cover is a pouch cell composed of FRB (Flame Resistance Barrier) or NCG (Non-Combustible Glassfiber) refractory material.

11. Includes a plurality of pouch cells according to paragraph 1, and The above plurality of pouch cells are a pouch cell assembly in which each hinge venting portion is arranged so as to be aligned in a certain direction.

12. In Paragraph 11, A pouch cell assembly having insulation pads further arranged between the plurality of pouch cells.

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