Battery pack

Abstract

The present invention relates to a battery pack in which a cell assembly is accommodated. The battery pack includes: a pack case in which a cell assembly is seated; and an upper case coupled to the pack case so as to cover the top portion of the cell assembly seated in the pack case, wherein the upper case includes, at the bottom thereof, an elastic member for pressing the top portion of the cell assembly seated in the pack case.

Description

battery pack

[0001] The present invention relates to a battery pack in which a cell assembly is accommodated.

[0002] This application claims the benefit of priority to Republic of Korea Patent Application No. 10-2023-0107108, dated August 16, 2023, and all contents of the document in said Korean patent application are incorporated herein by reference.

[0003]

[0004] Typically, a cell is composed of an electrode assembly in which electrodes and separators are alternately laminated, an electrode lead coupled to the electrodes of the electrode assembly, a case in which the electrode leads extend outward and surround the electrode assembly, and an electrolyte filled together with the electrode assembly inside the case.

[0005] The above cells can be broadly classified into cylindrical cells, pouch-shaped cells, and square cells depending on the shape of the case.

[0006] While cells can be used individually, they are often configured as multiple cells electrically connected in series and / or parallel. Specifically, multiple cells are electrically connected to each other to form a cell stack. Furthermore, the cell stack can be housed within a module frame to form a single cell assembly.

[0007] Figure 1 shows a cell assembly (20) containing a pouch-shaped cell (24), and Figure 2 shows a cell assembly (20) containing a square cell (24).

[0008] The pouch-shaped cells (24) are arranged so that the electrode leads (26) of each cell (24) are located on the side, as shown in the above-described Figure 1. Accordingly, the cell assembly (20) can have terminals formed on the side corresponding to the electrode leads (26) of the received cells (24).

[0009] A cell assembly (20) that accommodates a pouch-shaped cell (24) may have an end plate (21) coupled to the front and rear surfaces of a cell stack (25) to protect the terminal. Accordingly, the cell assembly (20) that accommodates a pouch-shaped cell (24) may have an external terminal electrically connected to the cell stack (25) provided on the end plate (21).

[0010] The square cells (24) are arranged so that the electrode leads (26) of each cell (24) face upward, as illustrated in the above-described FIG. 2. Accordingly, the cell assembly (20) may have terminals formed at the upper portion corresponding to the electrode leads (26) of the accommodated cells (24). Accordingly, the cell assembly (20) in which the square cells (24) are accommodated may have external terminals electrically connected to the cell stack (25) provided on the module frame (22) located at the upper portion of the cell stack (25).

[0011] The cell assembly (20) that accommodates the above-mentioned square cell (24) does not have a configuration such as an added end plate (21) due to the electrode lead (26) provided on the side as shown in FIG. 2.

[0012] The cell assembly (20) has a slight difference depending on the shape of the cell (24) accommodated inside as shown in the above drawings 1 and 2, but is the same in that the cell stack (25) inside is wrapped and protected by the module frame (22).

[0013] Cell assemblies (20) used in products requiring high output, such as electric vehicles, can be electrically connected in series and / or parallel to two or more of them to form a higher-level device, such as a battery pack.

[0014] Fig. 3 illustrates a conventional battery pack and a cell assembly (20) accommodated therein. In the case of a battery pack, the battery pack may include a pack case (10) into which the cell assembly (20) is directly inserted and accommodated, and an upper case coupled to the pack case (10) so that the internal space of the pack case (10) can be sealed from the outside. Each cell assembly (20) is accommodated in a partitioned space within the pack case (10) as illustrated in Fig. 3.

[0015] Meanwhile, in a cell assembly (20) including a plurality of cells (24) densely packed in a narrow space, a problem such as a short circuit may occur in some cells (24), causing the temperature to continuously rise, which may cause a thermal runaway phenomenon in which the temperature of the cell (24) exceeds a critical temperature. High-temperature gas and spark particles may be ejected from the cells (24) experiencing thermal runaway. (Here, the spark particles refer to active materials or molten aluminum particles detached from the electrodes inside the cells (24).) In addition, in some cases, a flame may occur in some cells (24).

[0016] When gas is generated inside the cell assembly (20) surrounded by the module frame (22) and the end plate (21) as described above, there is a risk that the cell assembly (20) may explode due to the gas pressure, and the explosion may transmit flames and heat to other cell assemblies (20). In order to solve the explosion problem as described above, a conventional cell assembly (20) may be formed with an opening (23) through which gas can be discharged.

[0017] Fig. 4 illustrates a conventional cell assembly (20) to which an opening hole (23) is applied. The cell assembly (20) to which the opening hole (23) is applied can prevent internal pressure from being generated by quickly discharging the gas even if the internal cell (24) experiences thermal runaway and generates high-temperature gas.

[0018] However, when an opening hole (23) is formed in the cell assembly (20) as described above, a problem frequently occurs in which spark particles and flames generated in the cell (24) are transferred to another cell assembly (20) through the opening hole (23).

[0019] Accordingly, the present invention was created to solve the above problems, and aims to provide a battery pack having a structure capable of effectively discharging gas generated internally to the outside in a thermal runaway situation.

[0020] In addition, the present invention aims to provide a battery pack having a structure capable of delaying heat transfer to other cell assemblies even if a thermal runaway phenomenon occurs in one cell assembly accommodated therein.

[0021] Other objects and advantages of the present invention can be understood through the following description and will be more clearly understood through the embodiments of the present invention. Furthermore, it will be readily apparent that the objects and advantages of the present invention can be realized by the means and combinations thereof set forth in the claims.

[0022] According to the present invention, a battery pack in which a cell assembly is accommodated is provided.

[0023] The battery pack includes a pack case in which a cell assembly is mounted; and an upper case coupled to the pack case to cover an upper portion of the cell assembly mounted inside the pack case; wherein the upper case is characterized in that it includes an elastic member at a lower portion that presses an upper portion of the cell assembly mounted in the pack case.

[0024] The above cell assembly may include a cell stack including a plurality of cells; and a module frame surrounding at least one side of the cell stack.

[0025] The above module frame may include an opening hole that allows the cell stack inside to be exposed to the outside.

[0026] The above opening can be formed in either a circular or polygonal shape.

[0027] The above opening hole can be formed to extend along either the longitudinal direction or the width direction of the cell assembly.

[0028] The above cell assembly may further include a protective sheet attached to the surface of the module frame to cover the opening hole.

[0029] The elastic member of the upper case may be formed at a location where the opening hole of the cell assembly is not provided.

[0030] The above opening can be formed on a module frame located at the upper portion of the cell assembly.

[0031] The above protective sheet may be a porous structure including a plurality of pores that selectively allow gases to pass through.

[0032] The above protective sheet may have a structure in which no pores are formed to prevent gas from passing through.

[0033] The above protective sheet may have electrical insulation properties.

[0034] The above protective sheet may have heat resistance and flame retardancy.

[0035] According to the present invention, in a battery pack accommodating a plurality of cell assemblies, even if a thermal runaway phenomenon occurs in one cell assembly, heat transfer to adjacent cell assemblies can be suppressed as much as possible, thereby improving safety against explosion.

[0036] Figure 1 illustrates a conventional cell assembly including pouch-shaped cells.

[0037] Figure 2 illustrates a conventional cell assembly including square cells.

[0038] Figure 3 illustrates a conventional battery pack and a cell assembly accommodated therein.

[0039] Figure 4 illustrates a conventional cell assembly.

[0040] Figure 5 illustrates a battery pack according to the first embodiment of the present invention.

[0041] Figure 6 illustrates a cell assembly of the present invention.

[0042] Figure 7 shows the protective sheet separated from the cell assembly of Figure 6.

[0043] Figure 8 is a bottom perspective view of the upper case.

[0044] Fig. 9 shows the upper case of the battery pack of Fig. 5 with a hidden line so that the elastic member is visible.

[0045] Figure 10 shows the upper case and pack case of Figure 9 combined.

[0046] Figure 11 is a simplified cross-section of a battery pack with one cell assembly mounted thereon.

[0047] Figure 12 shows the movement of gas generated when thermal runaway occurs in the cell stack in the battery pack of Figure 11.

[0048] Fig. 13 illustrates a battery pack according to a second embodiment of the present invention.

[0049] Figure 14 shows a cell assembly accommodated in Figure 13.

[0050] Figure 15 shows the protective sheet separated from the cell assembly of Figure 14.

[0051] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. Prior to this, it should be noted that the terms and words used in this specification and claims should not be construed as limited to their conventional or dictionary meanings. Based on the principle that the inventor can appropriately define the concept of a term to best explain his or her invention, they should be construed as meanings and concepts consistent with the technical spirit of the present invention.

[0052] Therefore, the embodiments described in this specification and the configurations illustrated in the drawings are only the most preferred embodiments of the present invention and do not represent all of the technical ideas of the present invention, and it should be understood that there may be various equivalents and modified examples that can replace them at the time of filing this application.

[0053] In addition, when describing the present invention, if it is determined that a detailed description of a related known configuration or function may obscure the gist of the present invention, the detailed description is omitted.

[0054] Since the embodiments of the present invention are provided to more fully explain the present invention to those skilled in the art, the shapes and sizes of components in the drawings may be exaggerated, omitted, or schematically illustrated for clearer explanation. Accordingly, the sizes and proportions of each component do not fully reflect the actual sizes or proportions.

[0055]

[0056]

[0057] The present invention relates to a battery pack that accommodates a plurality of cell assemblies, characterized in that an elastic member that presses the upper portion of the accommodated cell assemblies is applied.

[0058] FIGS. 5 to 12 relate to a battery pack according to a first embodiment of the present invention, and FIGS. 13 to 15 relate to a battery pack according to a second embodiment of the present invention.

[0059] Hereinafter, specific embodiments of the battery pack of the present invention will be described in detail with reference to the attached drawings. Note that the directions used in the following description to designate relative positions, such as front-back, up-down, left-right, etc., are intended to aid understanding of the invention, and unless otherwise specified, the directions depicted in the drawings will be used as a reference.

[0060] In addition, the cell assembly of the present invention may be in a form in which pouch-shaped cells are stored as in FIG. 1, or in a form in which square cells are stored as in FIG. 2. However, for convenience, the form in which pouch-shaped cells are stored as in FIG. 1 will be mainly described.

[0061]

[0062] (First embodiment)

[0063] Figure 5 illustrates a battery pack according to the first embodiment of the present invention.

[0064] The above battery pack includes a pack case (100) in which a cell assembly (300) is mounted, and an upper case (200) that is coupled to the pack case (100) to cover the upper portion of the cell assembly (300) mounted inside the pack case (100).

[0065]

[0066] The cell assembly (300) accommodated in the battery pack of the present invention is characterized in that an opening hole (321) is formed on one side and a protective sheet (340) covering the opening hole (321) is provided.

[0067] FIG. 6 illustrates a cell assembly (300) of the present invention, and FIG. 7 illustrates a protective sheet (340) separated from the cell assembly (300) of FIG. 6.

[0068] The above cell assembly (300) includes a cell stack (310) including a plurality of cells and a module frame (320) surrounding at least one side of the cell stack (310).

[0069] The above cell assembly (300) may further include an end plate (330) that protects the cell stack accommodated therein from external impact, etc., as illustrated in FIG. 6, and has an external terminal electrically connected to the cell stack.

[0070] The above module frame (320) includes a plurality of opening holes (321) that are opened so that the internal cell stack (310) is exposed to the outside, as shown in FIG. 7.

[0071] The above opening hole (321) is formed for the purpose of preventing the cell assembly (300) from exploding due to an increase in the pressure of the gas (g) inside the cell assembly (300) when a high temperature gas (g) is generated due to a thermal runaway phenomenon of the stored cell stack (310). That is, the opening hole (321) serves as a passage through which the gas (g) generated due to the thermal runaway phenomenon of the cell stack (310) escapes to the outside.

[0072] The above opening hole (321) is formed on the module frame (320) located above the cell assembly (300) of FIG. 7.

[0073] The above opening hole (321) can be formed in either a circular or polygonal shape.

[0074] The cell assembly (300) of the present invention further includes a protective sheet (340) attached to the surface of the module frame (320) to cover the opening hole (321).

[0075] The above protective sheet (340) covers one side of the module frame (320) in which the opening hole (321) is formed, thereby preventing flames and spark particles from flying out through the opening hole (321).

[0076] In addition, when one of the cell assemblies (300) accommodated in the protective sheet (340) undergoes thermal runaway and generates flame and gas, it serves to regulate the flame and gas from flowing into the opening hole (321) of another normal cell assembly (300).

[0077] The above protective sheet (340) preferably includes a material that is heat-resistant and flame-retardant so as not to be damaged by high-temperature gas (g) and not to burn in flames.

[0078] Additionally, the protective sheet (340) preferably includes a material having electrical insulation properties.

[0079] The above protective sheet (340) may have a structure in which no pores are formed to prevent gas from passing through, or may have a porous structure including a plurality of pores that selectively allow gas to pass through.

[0080] A protective sheet (340) having a structure in which no voids are formed is attached to seal the opening hole (321) of the cell assembly. Therefore, in the case of a cell assembly (300) to which the protective sheet (340) is normally attached, it is difficult for gases and flames, etc., to pass through the opening hole (321).

[0081] The protective sheet (340) has a pressure limit beyond which it is not deformed by external pressure, and may be damaged when pressure exceeding the pressure limit is applied. For example, the protective sheet (340) sealing the opening hole (321) as described above may be partially damaged when the pressure inside the cell assembly reaches the pressure limit range, thereby releasing gas and flames. In this case, a fracture line may be applied to the protective sheet (340) to intentionally open a desired area first.

[0082] The protective sheet (340) in which a gap is formed allows gas (g) generated by thermal runaway of the cell to pass through, but does not allow spark particles, etc. that may be generated together with the gas (g) to pass through.

[0083]

[0084] The above pack case (100) includes a base plate (110) that supports the lower portion of the cell assembly (300) and a side beam (120) that is coupled to the edge of the base plate (110) to support the side portion of the cell assembly (300).

[0085] Additionally, the pack case (100) may include a cross beam (130) whose lower end is joined to the base plate (110) to partition the internal space.

[0086] A plurality of cell assemblies (300) can be installed and separated from each other in the internal space of the pack case (100) partitioned by the cross beam (130), etc. At this time, each cell assembly (300) is arranged so that the opening hole (321) and the protective sheet (340) are facing upward, as shown in FIG. 5.

[0087]

[0088] The upper case (200) is coupled to the upper end of the side beam (120) of the pack case (100) so as to cover the upper portion of the cell assembly (300) installed inside the pack case (100) as shown in FIG. 5.

[0089] The above protective sheet (340) may be attached to the surface of the module frame (320) using an adhesive or glue. However, if the pressure of the gas (g) is very high and exceeds the adhesive force, the protective sheet (340) may fall off from the module frame (320). That is, when the pressure of the gas (g) is high, the protective sheet (340) may fall off from the surface of the module frame (320) and may not be able to perform its role of filtering spark particles and flames.

[0090] The battery pack of the present invention is characterized in that a structure capable of pressing the protective sheet (340) toward the module frame (320) is added to prevent the protective sheet (340) from being removed from the surface of the module frame (320) as described above.

[0091] Specifically, the upper case (200) includes an elastic member (210) at the bottom that presses the upper portion of the cell assembly (300) mounted on the pack case (100).

[0092] Figure 8 is a bottom perspective view of the upper case (200).

[0093] According to the above drawing 8, a plurality of elastic members (210) are formed at the bottom of the upper case (200).

[0094] Each of the above elastic members (210) may be, for example, a spring or a foam member having elastic restoring force, and is arranged to transmit elastic force downward based on the upper case (200).

[0095] FIG. 9 shows the upper case (200) of the battery pack of FIG. 5, with the elastic member (210) being treated with a hidden line so that it is visible.

[0096] The above elastic member (210) is formed at a position corresponding to each cell assembly (300).

[0097] The elastic member (210) is naturally pressed by the upper end of the cell assembly (300) as the upper case (200) and the pack case (100) are combined. That is, the elastic member (210) is pressed by the upper end of the cell assembly (300) and simultaneously transmits elastic force to the upper end of the cell assembly (300) and, conversely, presses the protective sheet (340) attached to the upper end of the cell assembly (300).

[0098] It is preferable that the elastic member (210) be extended to a degree that it can pressurize the upper portion of each cell assembly (300) when the upper case (200) is completely combined with the pack case (100). Accordingly, the protective sheet (340) attached to the module frame (320) of the cell assembly (300) can be pressed against the lower portion of the elastic member (210) and remain attached.

[0099] However, the opening hole (321) of the cell assembly (300) must not be completely blocked by the elastic member (210).

[0100] Figure 10 shows a state in which the upper case (200) and pack case (100) of Figure 9 are combined.

[0101] If the elastic member (210) blocks the opening hole (321), there is a risk of explosion as the gas (g) inside the cell assembly (300) cannot be smoothly discharged in the event of thermal runaway of the cell. In addition, there is a risk that the elastic member (210) may directly contact the internal cell stack (310) through the opening hole (321) and damage it.

[0102] The above elastic member (210) is formed at the bottom of the upper case (200) so as to be positioned out of alignment with the opening hole (321) of the cell assembly (300), as shown in FIG. 10.

[0103] Figure 11 is a simplified cross-section of a battery pack in which one cell assembly (300) is mounted.

[0104] According to the above drawing 11, each elastic member (210) formed at the bottom of the upper case (200) presses the module frame (320) in which the opening hole (321) is not located in the cell assembly (300).

[0105] Fig. 12 shows the movement of gas (g) generated when thermal runaway occurs in the cell stack (310) in the battery pack of Fig. 11.

[0106] Referring to the above Fig. 12, the gas (g) rising upward from the cell stack (310) passes through the opening hole (321) and the protective sheet (340) and moves between the upper case (200) and the cell assembly (300). That is, the gas (g) moves between the plurality of elastic members (210) interposed between the upper case (200) and the cell assembly (300) and can then be discharged to the outside.

[0107]

[0108]

[0109] *The battery pack of the present invention further includes a discharge hole (not shown) formed to communicate with the internal space so as to discharge gas (g) generated internally to the outside.

[0110] Accordingly, the battery pack of the present invention can discharge high-temperature gas (g) discharged through the opening hole (321) of the cell assembly (300) to the outside through the discharge hole.

[0111] The above discharge hole may be formed on one side of the side beam (120) of the pack case (100), or may be formed on one side of the upper case (200).

[0112]

[0113] (Second embodiment)

[0114] The shape of the opening hole (321) of the cell assembly (300) accommodated in the battery pack of the present invention may be a slit shape. That is, the opening hole (321) may be a shape that extends long in one direction.

[0115] FIG. 13 illustrates a battery pack according to a second embodiment of the present invention, FIG. 14 illustrates a cell assembly (300) accommodated in FIG. 13, and FIG. 15 illustrates a protective sheet (340) separated from the cell assembly (300) of FIG. 14.

[0116] According to the above drawings 13 to 15, the opening hole (321) is formed to extend along the longitudinal direction (d4) of the cell assembly (300).

[0117] The above opening hole (321) may have a shape extending along the width direction (d3) of the cell assembly (300) in addition to the shape illustrated above.

[0118]

[0119]

[0120] The present invention has been described in more detail through drawings and examples. However, the configurations described in the drawings or examples described in this specification are merely embodiments of the present invention and do not represent all of the technical ideas of the present invention. Therefore, it should be understood that various equivalents and modified examples may exist as of the time of this application.

[0121]

[0122] [Explanation of symbols]

[0123] 10: (Prior Art) Pack Case

[0124] 20: (Prior art) Cell assembly

[0125] 21: (Prior art) End plate

[0126] 22: (Prior art) Module frame

[0127] 23: (Previous technology) Opening hole

[0128] 24: (Prior art) Cell

[0129] 25: (Prior art) Cell stack

[0130] 26: (Prior art) Electrode lead

[0131] 100: Pack Case

[0132] 110: Base plate

[0133] 120: Side beam

[0134] 130: Cross beam

[0135] 200: Upper case

[0136] 210: Elastic member

[0137] 300: Cell assembly

[0138] 310: Cell Stack

[0139] 320: Module Frame

[0140] 321: Opening hole

[0141] 330: End Plate

[0142] 340: Protective sheet

[0143] g: gas

[0144] d1: Battery pack width direction

[0145] d2: Battery pack length direction

[0146] d3: Cell assembly width direction

[0147] d4: Cell assembly length direction

Claims

1. A battery pack in which a cell assembly is accommodated, A pack case in which the cell assembly is mounted; and An upper case coupled with the pack case to cover the upper portion of the cell assembly mounted inside the pack case; A battery pack characterized in that the upper case includes an elastic member at the lower end that presses the upper portion of the cell assembly mounted in the pack case.

2. In paragraph 1, The above cell assembly is, A cell stack comprising a plurality of cells; and A battery pack comprising a module frame surrounding at least one side of the cell stack.

3. In paragraph 2, A battery pack having a module frame having an opening through which the cell stack inside is exposed to the outside.

4. In paragraph 3, A battery pack wherein the above opening is formed in either a circular or polygonal shape.

5. In paragraph 3, A battery pack in which the above opening is formed to extend along one of the longitudinal and width directions of the cell assembly.

6. In paragraph 3, The above cell assembly is, A battery pack further comprising a protective sheet attached to the surface of the module frame to cover the opening.

7. In paragraph 6, A battery pack in which the elastic member of the upper case is formed in a position where the opening hole of the cell assembly is not provided.

8. In paragraph 6, A battery pack in which the above opening is formed on the module frame located at the upper part of the cell assembly.

9. In paragraph 6, A battery pack wherein the above protective sheet is a porous structure containing a plurality of pores that selectively allow gas to pass through.

10. In paragraph 6, The above protective sheet is a battery pack having a structure in which no gaps are formed to prevent gas from passing through.

11. In paragraph 6, The above protective sheet is a battery pack having electrical insulation properties.

12. In paragraph 6, The above protective sheet is a battery pack having heat resistance and flame retardancy.

Images