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 comprising a separator between a positive electrode and a negative electrode; a pouch surrounding and accommodating the electrode assembly; and a venting control plate having a bent surface to cover the upper surface of the pouch and having an opening provided in at least a portion of the bent surface. The pouch cell may further comprise a thermal pad disposed adjacent to the electrode assembly.

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. 10-2025-0030538 filed on March 10, 2025, and all contents of Korean Patent Application No. 10-2025-0030538 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 a venting control panel having a folded surface to cover the upper surface of the pouch and having an opening provided in at least a portion of the folded surface.

[0012] The above pouch cell further includes a thermal pad disposed adjacent to the electrode assembly.

[0013] The thermal pad can be supported by a support portion of the venting control panel extending from the bent surface.

[0014] The support portion of the above-described venting control panel may include: a first support surface extending from the bending surface and located between the electrode assembly and the thermal pad; a second support surface extending from the first support surface and located on the lower surface of the thermal pad; a third support surface extending upward from the second support surface and facing the first support surface; and a fourth support surface extending from the third support surface and covering the upper surface of the thermal pad.

[0015] The opening of the above-mentioned venting control panel may be located at the center of the above-mentioned bent surface.

[0016] The opening of the above-mentioned venting control panel may be formed in at least one or more places on the bent surface.

[0017] The first support surface may have a plurality of additional openings along the lower side of the opening.

[0018] The second support surface can be bonded to the lower surface of the thermal pad.

[0019] The above-mentioned fourth support surface can be opened in the same direction as the above-mentioned bending surface.

[0020] The above venting control panel may be composed of a metal plate or mica material.

[0021] The above pouch may have a region of the pouch corresponding to the opening that is thinner than the rest of the pouch.

[0022] 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 each venting control panel is aligned in a certain direction.

[0023] According to one embodiment of the present invention, by providing a venting control panel having an opening in a pouch cell, the direction of gas discharge can be precisely controlled from the pouch cell unit. Accordingly, swelling or thermal runaway of the pouch cell can be prevented.

[0024] 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.

[0025] FIG. 1 is a perspective view of a pouch cell according to one embodiment.

[0026] Figure 2 is a side view of Figure 1.

[0027] Figure 3 is a detailed view of part A of Figure 1.

[0028] FIG. 4 is a side view of another pouch cell according to one embodiment.

[0029] Figure 5 is an exploded perspective view of another pouch cell of Figure 4.

[0030] Figure 6 is an exploded perspective view of another pouch cell of Figure 5 viewed from the opposite side.

[0031] FIG. 7 is a perspective view of a pouch cell assembly in which other pouch cells of FIG. 4 are arranged.

[0032] Figure 8 is a schematic diagram of the BB line cross-section of Figure 7.

[0033] Figure 9 is a perspective view of the pouch cell of Figure 8.

[0034] Figure 10 is a cross-sectional schematic diagram illustrating the operation of another pouch cell of Figure 8.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039]

[0040] (1st embodiment)

[0041] 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.

[0042] 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).

[0043] 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).

[0044] 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.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] 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.

[0049] 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).

[0050] 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.

[0051] Meanwhile, the pouch cell (100) according to the present embodiment includes a venting control panel (140) that surrounds at least a portion of the pouch (120). The pouch cell (100) can control the direction of the gas discharged through the venting control panel (150) at a constant rate.

[0052] The venting control panel (140) may have a supporting surface (141) on one side of the pouch (120), a folded surface (145) to cover the top surface of the pouch (120), and an opening (146) may be provided in at least a part of the folded surface (145).

[0053] The opening (146) of the venting control panel (140) may be located in the center of the folded surface (145). At least one opening (146) may be formed in the folded surface (145). The opening (146) may be formed in any one of the shapes of a square, polygon, semicircle, ellipse, and rhombus, and may have various shapes.

[0054] The pouch (120) may have a thinner thickness in the area of ​​the pouch (120) corresponding to the opening (146) than in the rest of the pouch (120). To thin a portion of the thickness of the pouch (120), the corresponding area of ​​the pouch (120) may be punched repeatedly several times.

[0055]

[0056] (2nd Example)

[0057] FIG. 4 is a side view of another pouch cell (200) according to one embodiment, and FIG. 5 is an exploded perspective view of the other pouch cell (200) of FIG. 4. FIG. 6 is an exploded perspective view of the other pouch cell (200) of FIG. 5, viewed from the opposite side.

[0058] Referring to FIGS. 4 to 6, the pouch cell (200) according to the second embodiment includes an electrode assembly (210), a pouch (220), and an electrode lead (230), similar to the pouch cell (100) according to the first embodiment, but a redundant description thereof is omitted.

[0059] The pouch cell (200) according to the second embodiment further includes a thermal pad (250) adjacent to the electrode assembly (210).

[0060] The thermal pad (250) effectively disperses and dissipates heat generated inside the pouch cell (200). The thermal pad (250) quickly absorbs the heat generated in the pouch cell (200) and transfers it to a heatsink or an external case to prevent the pouch cell (200) from overheating.

[0061] The thermal pad (250) can be supported by a support portion of the venting control panel (240) extending from the folded surface (245).

[0062] The support portion of the venting control panel (240) includes first to fourth support surfaces (241, 242, 243, 244).

[0063] The first support surface (241) extends downward from the folded surface (245) and is located between the electrode assembly (210) and the thermal pad (240). The first support surface (241) may further have a plurality of openings (247, 248) along the lower side of the opening (246). The central part of the pouch cell (200) is more prone to swelling than other parts. Accordingly, the venting control panel (240) can respond more flexibly to the swelling phenomenon of the pouch cell (200) through the plurality of openings (247, 248) formed in the first support surface (241), and is advantageous for preventing deformation of the pouch.

[0064] The second support surface (242) extends from the first support surface (241) and is located on the lower surface of the thermal pad (250). The second support surface (242) can be bonded to the lower surface of the thermal pad (250).

[0065] The third support surface (243) may extend upward from the second support surface (242) and be positioned facing the first support surface (241). The third support surface (243) is positioned between the thermal pad (250) and the adjacent pouch cell.

[0066] The fourth support surface (244) extends from the third support surface (243) and can cover the top of the thermal pad (250). The fourth support surface (244) can be opened in the same direction as the folded surface (245). If necessary, the fourth support surface (244) may not be installed in the pouch cell (200).

[0067] The venting control panel (240) may be composed of a metal plate or a mica material. The venting control panel (240) may have the first to fourth support surfaces (241, 242, 243, 244) formed integrally as well as the bent surface (245).

[0068] The opening (246) of the venting control panel (240) can be formed in the folding area (211) of the electrode assembly (210).

[0069] In the case of a pouch cell (200) according to the second embodiment, if a venting control panel (240) supported by a thermal pad (250) is placed between electrode assemblies (210), the gas discharge position and direction of the pouch cell (200) can be controlled through the opening (246) of the venting control panel (240), and the gas can be discharged in an intended direction from a battery module or battery pack to which the pouch cell (200) is applied.

[0070] These pouch cells (200) may be composed of a plurality of them as described below, and the plurality of pouch cells (200) may be stacked so as to be electrically connected to each other to form a pouch cell assembly.

[0071]

[0072] (3rd Example)

[0073] FIG. 7 is a perspective view of a pouch cell assembly (200') in which other pouch cells (200) of FIG. 4 are arranged, FIG. 8 is a schematic cross-sectional view along the BB line of FIG. 7, and FIG. 9 is a perspective view of a pouch cell (200) of FIG. 8.

[0074] Referring to the drawings, the pouch cell assembly (200') according to the present embodiment may have a plurality of pouch cells (200) arranged along the Z-axis direction (thickness direction of the pouch cells). For convenience of explanation, the length direction of the pouch cells (200) 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.

[0075] A pouch cell assembly (200') can be assembled by arranging a plurality of pouch cells (200) such that each venting control panel (240) is aligned in a certain direction of the Z-axis, and surrounding the plurality of pouch cells (200) with a plurality of tapes (T).

[0076] 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.

[0077] The pouch cell assembly (200') can be directly seated in a battery pack without a separate module frame, with at least one pouch cell (200) assembled in multiple units and assembled by a tape (T).

[0078] 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.

[0079] 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.

[0080] 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.

[0081] 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 the cell unit is seated and the cell unit. This heat sink may be configured to cool the cell unit by making thermal contact with a thermal pad (250) placed between the pouch cells (200). To this end, the heat sink may be made of a metal material with high thermal conductivity and heat resistance.

[0082] In one embodiment, an insulating pad may be further arranged between the plurality of pouch cells.

[0083] 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.

[0084] The cell unit may include a busbar, a busbar frame, and an insulating cover.

[0085] The above busbar can be configured to be electrically connected to the electrode lead (230) of at least one pouch cell (200).

[0086] 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.

[0087] The above insulating cover may be configured to prevent a short circuit of the electrode lead (230) or busbar. To this end, the insulating cover may be composed of an insulating polymer synthetic resin.

[0088] FIG. 10 is a cross-sectional schematic diagram illustrating the operation of another pouch cell (200) of FIG. 8.

[0089] FIG. 10 is a schematic cross-sectional view of the BB line of FIG. 7, where FIG. 8 shows the state of the pouch cell assembly (200') before the event occurs and FIG. 10 shows the state after the event occurs. In FIG. 8 and FIG. 10, only two pouch cells (200A, 200B) with a thermal pad (250) in between are shown for convenience of explanation.

[0090] Referring to the drawing, if a large amount of gas is generated inside the pouch cell (200A) due to factors such as overcharging, exposure to high temperature, or internal short circuit, the internal pressure of the pouch cell (200A) increases, and gas or flame will be generated inside the pouch cell (200A). At this time, a venting control panel (240) is provided in the folding area (211A) of the pouch cell (200A), and a folded surface (245) having an opening (246) is provided on the upper part of the venting control panel (240). Therefore, even if the internal gas or flame of the pouch cell (200A) is ejected from any direction, the venting gas or flame can be guided in a specific direction as indicated by the arrow through the opening (256) of the folded surface (245) of the venting control panel (240).

[0091] Therefore, even if pouch cells (200A, 200B) 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 (200A, 200B) can be precisely controlled.

[0092] As described above, the pouch cell (200) according to the present invention is provided with a venting control panel (240) in the pouch (220), and by forming an opening (246) in the folded surface (245) of the venting control panel (240), the direction of gas discharge can be precisely controlled from the pouch cell unit, thereby preventing swelling or thermal runaway of the pouch cell.

[0093] In addition, when a plurality of pouch cells (200A, 200B) 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 or the like in a specific direction, thereby ensuring reliable protection of other pouch cells.

[0094] 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 A pouch cell comprising: a venting control panel having a folded surface to cover the upper surface of the pouch and having an opening provided in at least a portion of the folded surface.

2. In Paragraph 1, A pouch cell further comprising a thermal pad disposed adjacent to the electrode assembly.

3. In Paragraph 2, The above thermal pad is a pouch cell supported by a support portion of the venting control panel extending from the above folded surface.

4. In Paragraph 3, The support portion of the above-mentioned venting control panel is, A first support surface extending from the above-mentioned bending surface and located between the electrode assembly and the thermal pad; A second support surface extending from the first support surface and located on the lower surface of the thermal pad; A third support surface extending upward from the second support surface and facing the first support surface; and A pouch cell comprising: a fourth support surface extending from the third support surface and covering the top of the thermal pad.

5. In Paragraph 1, The opening of the above-mentioned venting control panel is a pouch cell located at the center of the above-mentioned folded surface.

6. In Paragraph 1, The opening of the above-mentioned venting control panel is a pouch cell formed in at least one place on the folded surface.

7. In Paragraph 4, The above first support surface is a pouch cell having a plurality of additional openings along the lower side of the opening.

8. In Paragraph 4, The above second support surface is a pouch cell bonded to the lower surface of the above thermal pad.

9. In Paragraph 4, The above-mentioned fourth support surface is a pouch cell that is open in the same direction as the above-mentioned fold surface.

10. In Paragraph 1, The above venting control panel is a pouch cell composed of a metal plate or mica material.

11. In Paragraph 1, The above pouch is a pouch cell in which the area of ​​the pouch corresponding to the opening is thinner than the remaining area of ​​the pouch.

12. 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 venting control panel is arranged so as to be aligned in a certain direction.

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