Battery pack

Abstract

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

Description

Technical Field

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

[0002] This application claims the benefit of priority from Korean Patent Application No. 10-2023-0107108, filed on August 16, 2023, the disclosure of which is incorporated herein by reference. Background Art

[0003] Generally, a battery cell includes: an electrode assembly, which is stacked with alternating layers of electrodes and separators; an electrode lead, which is connected to the electrodes of the electrode assembly; a shell, from which the electrode lead is led to the outside, and the shell surrounds the electrode assembly; and an electrolyte, which is filled inside the shell together with the electrode assembly.

[0004] According to the shape of the shell, battery cells can be roughly divided into cylindrical batteries, pouch-type batteries and prismatic batteries.

[0005] While battery cells are sometimes used individually, they are more commonly configured as multiple cells electrically connected in series and / or in parallel. Specifically, multiple cells are electrically connected to form a cell stack. Furthermore, the cell stack can be stored within a module frame to form a single cell assembly.

[0006] Figure 1 The battery cell assembly 20 containing the pouch-type battery cell 24 is shown, and Figure 2 A cell assembly 20 housing prismatic cells 24 is shown.

[0007] like Figure 1 As shown, the pouch-type battery cells 24 are arranged so that the electrode lead 26 of each battery cell 24 is located on the side. Therefore, the battery cell assembly 20 may be formed with a terminal on the side corresponding to the electrode lead 26 of the accommodated battery cell assembly 24.

[0008] The cell assembly 20 containing the pouch-type cells 24 may have end plates 21 coupled to the front and rear surfaces of the cell stack 25 to protect the terminals. Therefore, the cell assembly 20 containing the pouch-type cells 24 may be provided with external terminals electrically connected to the cell stack 25 on the end plates 21.

[0009] like Figure 2 As shown, the prismatic cells 24 are arranged so that the electrode leads 26 of each cell 24 face upward. Therefore, the cell assembly 20 can be formed with terminals on the upper portion corresponding to the electrode leads 26 of the accommodated cell 24. Therefore, the cell assembly 20 accommodating the prismatic cells 24 can be provided with external terminals electrically connected to the cell stack 25 on the module frame 22, and the external terminals are located on the upper portion of the cell stack 25.

[0010] like Figure 2 As shown, the cell assembly 20 accommodating the prismatic cell 24 is not affected by the configuration of the end plate 21 added due to the electrode lead 26 provided on the side.

[0011] like Figure 1 and Figure 2 As shown, the cell assemblies 20 have slight variations based on the shape of the cells 24 housed therein, but are otherwise identical in that the cell stack 25 inside is surrounded and protected by the module frame 22 .

[0012] The battery cell assembly 20 used in products requiring high power (eg, electric vehicles) may be one in which two or more battery cell assemblies are electrically connected to each other in series and / or in parallel to form a higher-level device (eg, a battery pack).

[0013] Figure 3 A conventional battery pack and a cell assembly 20 housed therein are shown. The battery pack may include a battery pack case 10, and an upper case, the cell assembly 20 being directly inserted into and housed in the battery pack case 10, and the upper case being coupled to the battery pack case 10 so that the space inside the battery pack case 10 is sealed from the outside. Figure 3 As shown, each of the battery cell assemblies 20 is stored in a separate space within the battery pack case 10 .

[0014] Furthermore, in a battery cell assembly 20 that includes multiple battery cells 24 tightly packed together in a small space, some of the battery cells 24 may experience a problem (e.g., a short circuit) that causes the temperature of the battery cells 24 to continue to rise, thereby causing the temperature of the battery cells 24 to exceed a threshold temperature, a phenomenon known as thermal runaway. High-temperature gases and spark particles may be ejected from the thermally runaway battery cells 24 (spark particles refer to, for example, active material or molten aluminum particles that are dislodged from the electrodes within the battery cells 24). Furthermore, in some cases, some of the battery cells 24 may even burst into flames.

[0015] As described above, if gas is generated inside the cell assembly 20 surrounded by the module frame 22 and the end plates 21, there is a risk that the cell assembly 20 may explode due to the gas pressure, and the explosion may cause flames and heat to be transferred to other cell assemblies. Conventional cell assemblies 20 may be formed with openings 23 through which gas can be discharged to solve the above-mentioned explosion problem.

[0016] Figure 4 The conventional battery cell assembly 20 having the opening hole 23 is shown. The battery cell assembly 20 having the opening hole 23 can prevent internal pressure from being generated by quickly discharging the high-temperature gas even if the battery cells 24 therein generate high-temperature gas due to thermal runaway.

[0017] However, when the opening holes 23 are formed in the cell assemblies 20 as described above, a problem frequently occurs in which spark particles and flames generated in the cell 24 are transferred to other cell assemblies 20 through the opening holes 23 . Summary of the Invention

[0018] Technical issues

[0019] Therefore, the present disclosure is directed to solving the above-mentioned problems and providing a battery pack having a structure capable of effectively discharging internally generated gas to the outside in the event of thermal runaway.

[0020] Another object of the present disclosure is to provide a battery pack having a structure capable of delaying heat transfer to other battery packs even if thermal runaway occurs in any one of the battery cell assemblies accommodated therein.

[0021] Other purposes and advantages of the present disclosure will be understood from the following description and will become more apparent from the embodiments of the present disclosure. It is also obvious that the purposes and advantages of the present disclosure can be achieved by the means disclosed in the patent claims and their combinations.

[0022] Technical Solution

[0023] The present disclosure provides a battery pack in which a battery cell assembly is housed.

[0024] The battery pack includes: a battery pack case in which a cell assembly is disposed; and an upper case connected to the battery pack case to cover an upper portion of the cell assembly disposed inside the battery pack case, wherein the upper case includes an elastic member at a lower end that pressurizes the upper portion of the cell assembly disposed in the battery pack case.

[0025] The battery cell assembly may include: a battery cell stack including a plurality of battery cells; and a module frame surrounding at least one side of the battery cell stack.

[0026] The module frame may include an opening hole opened to expose the battery cell stack in the module frame to the outside.

[0027] The opening hole may be formed in either a circular shape or a polygonal shape.

[0028] The opening hole may extend along at least one of a length direction and a width direction of the battery cell assembly.

[0029] The battery cell assembly may further include a protection sheet attached to a surface of the module frame to cover the opening hole.

[0030] The elastic member of the upper case may be formed in a position where the opening hole of the battery cell assembly is not provided.

[0031] The opening hole may be formed on a module frame located on an upper portion of the battery cell assembly.

[0032] The protection sheet may be a porous structure including a plurality of pores through which gas selectively passes.

[0033] The protective sheet may have a structure without forming pores to prevent gas from passing through.

[0034] The protective sheet may have electrical insulating properties.

[0035] The protective sheet may have heat resistance and flame retardancy.

[0036] Beneficial effects

[0037] According to the present disclosure, in a battery pack accommodating a plurality of battery cell assemblies, even if thermal runaway occurs in one of the battery cell assemblies, heat transfer to other adjacent battery cell assemblies can be suppressed to the greatest extent, thereby improving safety against explosion. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 A conventional battery cell assembly including pouch-type battery cells is shown.

[0039] Figure 2 A conventional cell assembly including prismatic cells is shown.

[0040] Figure 3 A conventional battery pack and the battery cell assemblies housed therein are shown.

[0041] Figure 4 A conventional battery cell assembly is shown.

[0042] Figure 5 A battery pack according to a first embodiment of the present disclosure is shown.

[0043] Figure 6 A battery cell assembly of the present disclosure is shown.

[0044] Figure 7 Shown from Figure 6 Remove the protective sheet from the battery cell assembly.

[0045] Figure 8 It is a bottom perspective view of the upper shell.

[0046] Figure 9 The upper housing is shown using hidden lines to illustrate the Figure 5 An elastic member in a battery pack.

[0047] Figure 10 Shown Figure 9 The upper shell and the battery pack shell are connected together.

[0048] Figure 11 is a simplified cross-sectional view of a battery pack with one of the battery cell assemblies positioned therein.

[0049] Figure 12 shows the period of thermal runaway in the cell stack Figure 11 Migration of gases in the battery pack.

[0050] Figure 13 A battery pack according to a second embodiment of the present disclosure is shown.

[0051] Figure 14 Shown Figure 13 The battery cell components contained therein.

[0052] Figure 15 Shown from Figure 14 Remove the protective sheet from the battery cell assembly. DETAILED DESCRIPTION

[0053] Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Prior to this, it should be noted that the terms or words used in this specification and claims should not be interpreted in their ordinary or dictionary meanings, but rather, based on the principle that the inventor can appropriately define the concept of the term to best describe his / her invention, and should be interpreted in a meaning and concept consistent with the technical concept of the present invention.

[0054] Therefore, it should be understood that the embodiments described herein and the configurations shown in the drawings are merely the most preferred embodiments of the present disclosure and are not intended to exhaust the technical concept of the present invention, and that various equivalents and modifications may exist that may replace them upon submission.

[0055] Furthermore, in describing the present invention, where it is determined that a detailed description of related known configurations or features would obscure the essence of the present invention, such detailed description is omitted.

[0056] Since the embodiments of the present disclosure are provided to more fully explain the present disclosure to those skilled in the art, the shapes and sizes of the components in the drawings may be exaggerated, omitted, or schematically illustrated for the sake of clarity. Therefore, the size or ratio of each component does not necessarily indicate its actual size or ratio.

[0057] The present disclosure relates to a battery pack containing a plurality of battery cell assemblies, characterized in that the battery pack comprises an elastic member having a structure for pressurizing an upper portion of the contained battery cell assemblies.

[0058] Figures 5 to 12 relates to a battery pack according to a first embodiment of the present disclosure, and Figures 13 to 15 A battery pack according to a second embodiment of the present disclosure is provided.

[0059] Hereinafter, the specific embodiments of the battery pack of the present disclosure will be described in detail with reference to the accompanying drawings. For reference, unless otherwise defined, the relative positioning names used in the following description (such as front-to-back or top-to-bottom) are intended to help understand the present disclosure and refer to the orientation shown in the accompanying drawings.

[0060] In addition, the battery cell assembly of the present disclosure may be as follows Figure 1 The storage of pouch cells is shown, or as Figure 2 The storage is shown in the form of prismatic cells, but for convenience, the description will focus on the storage Figure 1 In the form of pouch-type batteries.

[0061] (First embodiment)

[0062] Figure 5 A battery pack according to a first embodiment of the present disclosure is shown.

[0063] The battery pack includes a pack case 100 in which the cell assembly 300 is seated, and an upper case 200 coupled to the pack case 100 to cover an upper portion of the cell assembly 300 seated within the pack case 100 .

[0064] The battery cell assembly 300 housed in the battery pack of the present disclosure is characterized in that an opening hole 321 is formed at one side and a protection sheet 340 covering the opening hole 321 is provided.

[0065] Figure 6 The battery cell assembly 300 of the present disclosure is shown, and Figure 7 Shown from Figure 6 The protective sheet 340 is removed from the battery cell assembly 300 .

[0066] The battery cell assembly 300 includes a battery cell stack 310 including a plurality of battery cells and a module frame 320 surrounding at least one side of the battery cell stack 310 .

[0067] like Figure 6 As shown, the battery cell assembly 300 may further include an end plate 330 , which protects the battery cell stack 310 accommodated in the battery cell assembly 300 from external impact, etc., and has an external terminal electrically connected to the battery cell stack 310 .

[0068] like Figure 7 As shown, the module frame 320 includes a plurality of opening holes 321 , which are opened to expose the battery cell stack 310 inside to the outside.

[0069] The opening holes 321 are formed to prevent the cell assembly 300 from exploding due to an increase in the pressure of the gas (g) inside the cell assembly 300 when high-temperature gas (g) is generated due to thermal runaway of the stored cell stack 310. In other words, the opening holes 321 serve as a path for the gas (g) generated by thermal runaway of the cell stack 310 to escape to the outside.

[0070] The opening hole 321 is formed relative to Figure 7 The battery cell assembly 300 is located on the upper module frame 320 .

[0071] The opening hole 321 may be formed in any one of a circular shape and a polygonal shape.

[0072] The battery cell assembly 300 of the present disclosure further includes a protection sheet 340 attached to a surface of the module frame 320 to cover the opening hole 321 .

[0073] The protection sheet 340 covers one side of the module frame 320 where the opening hole 321 is formed, to regulate the escape of flames, spark particles, etc. through the opening hole 321 .

[0074] In addition, in the event that thermal runaway occurs in any of the housed battery cell assemblies 300 , the protection sheet 340 is used to restrict flames and gas from entering the openings 321 of other normal battery cell assemblies 300 .

[0075] The protection sheet 340 preferably includes a heat-resistant and flame-retardant material so as not to be damaged by the high-temperature gas (g) and not to be burned by flames.

[0076] Furthermore, the protective sheet 340 preferably includes a material having electrical insulating properties.

[0077] The protection sheet 340 may have a non-porous structure that does not allow gas to pass through, or may have a porous structure including a plurality of pores that selectively allow gas to pass through.

[0078] The protective sheet 340 having a non-porous structure is attached to seal the opening hole of the cell assembly. Therefore, in the case of the cell assembly 300 with the protective sheet 340 attached normally, it is difficult for gas, flame, etc. to pass through the opening hole 321.

[0079] The protective sheet 340 has a limit pressure below which it will not deform due to external pressure. However, when pressure exceeding this limit is applied, the protective sheet 340 can be damaged. For example, as described above, when the pressure inside the battery cell assembly 300 reaches the limit pressure range, the protective sheet 340 sealing the opening 321 may partially rupture, releasing gas and flames. In this case, the protective sheet 340 may have a fracture line applied thereto to intentionally open the desired area first.

[0080] The porous protection sheet 340 allows the gas (g) generated due to thermal runaway of the battery cell to pass through, but does not allow spark particles that may be generated along with the gas (g) to pass through.

[0081] The battery pack case 100 includes a base plate 110 that supports a lower portion of the battery cell assembly 300 and a side beam 120 coupled to an edge of the base plate 110 to support a side portion of the battery cell assembly 300 .

[0082] In addition, the battery pack case 100 may include a beam 130 having a lower end coupled to the base plate 110 to partition the internal space.

[0083] The plurality of cell assemblies 300 may be separately arranged and placed in the inner space of the battery pack housing 100 partitioned by the crossbeam 130 or the like. Figure 5 As shown, each battery cell assembly 300 is arranged so that the opening hole 321 and the protection sheet 340 serve as the upper surface.

[0084] like Figure 5 As shown, the upper case 200 is coupled to the upper end of the side member 120 of the pack case 100 so that the upper portion of the battery cell assembly 300 positioned inside the pack case 100 is covered.

[0085] The protective sheet 340 may be attached to the surface of the module frame 320 by adhesive or glue, etc. However, when the pressure of the gas (g) is very large and exceeds the attachment force, the protective sheet 340 may fall off the module frame 320. In other words, when the pressure of the gas (g) is large, the protective sheet 340 may peel off from the surface of the module frame 320 and may not function to filter spark particles and flames, etc.

[0086] As described above, the battery pack of the present disclosure is characterized by the addition of a structure capable of pressing the protection sheet 340 toward the module frame 320 to prevent the protection sheet 340 from being removed from the surface of the module frame 320 .

[0087] Specifically, the upper case 200 includes an elastic member 210 at a lower end thereof, which pressurizes an upper portion of the battery cell assembly 300 positioned in the pack case 100 .

[0088] Figure 8 It is a bottom perspective view of the upper housing 200.

[0089] Reference Figure 8 , a plurality of elastic members 210 are formed at the lower end of the upper case 200 .

[0090] Each of the elastic members 210 may be, for example, a spring or a foam member having elasticity, and is provided to transmit elastic force downward with respect to the upper case 200 .

[0091] Figure 9 The upper housing 200 is shown with hidden lines so that Figure 5 The elastic member 210 of the battery pack is visible.

[0092] The elastic member 210 is formed at a position corresponding to each of the battery cell assemblies 300 .

[0093] When the upper case 200 and the battery pack case 100 are coupled, the elastic member 210 is naturally pressed by the upper end of the battery cell assembly 300. That is, the elastic member 210 is pressed against the upper end of the battery cell assembly 300 and simultaneously transmits elastic force to the upper portion of the battery cell assembly 300, thereby pressurizing the protective sheet 340 attached to the upper portion of the battery cell assembly 300.

[0094] Preferably, when the upper case 200 is fully coupled to the pack case 100, the elastic member 210 extends sufficiently to pressurize the upper portion of each battery cell assembly 300. Therefore, the protective sheet 340 attached to the module frame 320 of the battery cell assembly 300 can be pressed against the lower end of the elastic member 210 and maintained attached.

[0095] However, the opening hole 321 of the battery cell assembly 300 should not be completely blocked by the elastic member 210 .

[0096] Figure 10 Shown Figure 9 The upper case 200 and the battery pack case 100 are coupled together.

[0097] If the elastic member 210 blocks the opening 321, the gas (g) inside the cell assembly 300 may not be able to escape smoothly in the event of thermal runaway of the battery, which may cause an explosion. In addition, the elastic member 210 may directly contact and damage the internal cell stack 310 through the opening 321.

[0098] like Figure 10 As shown, the elastic member 210 is formed at the lower end of the upper case 200 such that it is formed at a misaligned position with respect to the opening hole 321 of the battery cell assembly 300 .

[0099] Figure 11 is a simplified cross-sectional view of a battery pack in which one of the battery cell assemblies 300 is positioned.

[0100] Reference Figure 11 Each of the elastic members 210 formed at the lower end of the upper case 200 pressurizes the module frame 320 at a position where the positioning opening hole 321 is not provided in the battery cell assembly 300 .

[0101] Figure 12It shows that when the battery cell stack 310 is in thermal runaway Figure 11 Migration of gas (g) in the battery pack.

[0102] Reference Figure 12 The gas (g) rising upward from the cell stack 310 passes through the opening holes 321 and the protective sheet 340 and travels between the upper case 200 and the cell assembly 300. That is, the gas (g) may travel between the plurality of elastic members 210 interposed between the upper case 200 and the cell assembly 300 and then be exhausted to the outside.

[0103] *The battery pack of the present disclosure further includes a discharge hole (not shown) formed to communicate with the internal space to allow gas (g) generated inside to be discharged to the outside.

[0104] Therefore, the battery pack of the present disclosure may allow the high-temperature gas (g) exhausted through the opening hole 321 of the battery cell assembly 300 to be exhausted to the outside through the exhaust hole.

[0105] The drain hole may be formed on one side of the side member 120 of the pack case 100 , or may be formed on one side of the upper case 200 .

[0106] (Second embodiment)

[0107] The opening hole 321 of the cell assembly 300 accommodated in the battery pack of the present disclosure may be slit-shaped, that is, the opening hole 321 may be elongated in any direction.

[0108] Figure 13 shows a battery pack according to a second embodiment of the present disclosure, Figure 14 Shown Figure 13 The cell assembly 300 contained therein, and Figure 15 Shown from Figure 14 The protective sheet 340 is removed from the battery cell assembly 300 .

[0109] Reference Figures 13 to 15 The opening hole 321 is formed to extend along the length direction d4 of the battery cell assembly 300 .

[0110] In addition to the shape shown, the opening hole 321 may also have a shape extending along the width direction d3 of the battery cell assembly 300 .

[0111] The present disclosure has been described in more detail above with reference to the accompanying drawings and embodiments. However, it should be understood that the configuration shown in the drawings or the embodiments described herein is only one embodiment of the present invention and does not represent the entire technical concept of the present invention, and various equivalents and modifications that can replace them when filing this application may exist.

[0112] [Explanation of Reference Numerals]

[0113] 10: (Prior art) Battery pack housing 20: (Prior art) Cell assembly 21: (Prior art) End plate

[0114] 22: (Prior art) Module frame 23: (Prior art) Opening hole

[0115] 24: (Existing technology) battery cell

[0116] 25: (Prior art) Battery cell stack 26: (Prior art) Electrode lead 100: Battery pack housing

[0117] 110: Substrate

[0118] 120: Side beam

[0119] 130: beam

[0120] 200: Upper shell

[0121] 210: Elastic member

[0122] 300: Battery cell components

[0123] 310: Battery cell stack

[0124] 320: Module Framework

[0125] 321: Opening hole

[0126] 330: End plate

[0127] 340: Protective sheet

[0128] g: gas

[0129] d1: width of battery pack

[0130] d2: battery pack length direction

[0131] d3: width direction of battery cell assembly

[0132] d4: length direction of battery cell assembly

Claims

1. A battery pack, wherein a battery cell assembly is housed therein, the battery pack comprising: a battery pack housing in which the battery cell assembly is housed; as well as an upper housing coupled to the battery pack housing to cover an upper portion of the battery cell assembly disposed inside the battery pack housing, wherein: The upper case includes an elastic member at a lower end that pressurizes an upper portion of the cell assembly positioned in the pack case.

2. The battery pack according to claim 1, wherein: The battery core assembly includes: A battery cell stack comprising a plurality of battery cells; and A module frame surrounds at least one side of the battery cell stack.

3. The battery pack according to claim 2, wherein: The module frame includes an opening hole that opens to expose the battery cell stack in the module frame to the outside.

4. The battery pack according to claim 3, wherein: The opening hole is formed in either a circular shape or a polygonal shape.

5. The battery pack according to claim 3, wherein: The opening hole extends along at least one of a length direction and a width direction of the battery cell assembly.

6. The battery pack according to claim 3, wherein: The battery cell assembly further includes: A protection sheet is attached to a surface of the module frame to cover the opening hole.

7. The battery pack according to claim 6, wherein: The elastic member of the upper case is formed in a position where the opening hole of the battery cell assembly is not provided.

8. The battery pack according to claim 6, wherein: The opening hole is formed on the module frame located on an upper portion of the battery cell assembly.

9. The battery pack according to claim 6, wherein: The protective sheet has a porous structure including a plurality of pores through which gas selectively passes.

10. The battery pack according to claim 6, wherein: The protective sheet has no pores formed therein to prevent gas from passing therethrough.

11. The battery pack according to claim 6, wherein: The protective sheet has electrical insulation properties.

12. The battery pack according to claim 6, wherein: The protective sheet has heat resistance and flame retardancy.

Images