Battery pack

Abstract

The present invention relates to a battery pack that houses a cell assembly, and includes a pack case in which the cell assembly is mounted, and an upper case that is coupled to the pack case to cover an upper portion of the cell assembly mounted inside the pack case, and the upper case includes a protrusion that applies pressure to the upper portion of the cell assembly mounted in the pack case.

Description

[Technical Field]

[0001] The present invention relates to a battery pack that houses a cell assembly.

[0002] This application claims the benefit of priority based on Korean Patent Application No. 10-2023-0107092 filed on August 16, 2023, and all contents disclosed in the literature of said Korean patent application are incorporated as part of the present specification. [Background Art]

[0003] Generally, a cell is constituted by an electrode assembly in which electrodes and separation membranes are alternately stacked, an electrode lead coupled to the electrode of the electrode assembly, a case from which the electrode lead is led out to the outside and surrounds the electrode assembly, and an electrolyte filled together with the electrode assembly inside the case.

[0004] The cells can be broadly classified into cylindrical cells, pouch-type cells, and prismatic cells according to the shape of the case.

[0005] On the other hand, although cells may be used alone, in many cases they are generally configured in a form where a large number of cells are electrically connected to each other in series and / or parallel. In particular, a large number of cells form a single cell stack in a state where they are electrically connected to each other. Further, the cell stack can be housed inside a module frame to form a single cell assembly.

[0006] Figure 1 shows a cell assembly 20 housing pouch-type cells 24, and Figure 2 shows a cell assembly 20 housing prismatic cells 24.

[0007] As shown in Figure 1, the pouch-type cells 24 are arranged such that the electrode leads 26 of each cell 24 are positioned at the side. Therefore, the cell assembly 20 can have terminals formed on the side portion corresponding to the electrode leads 26 of the housed cells 24.

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

[0009] As shown in Figure 2 above, the rectangular cells 24 are arranged so that the electrode leads 26 of each cell 24 face upward. Therefore, the cell assembly 20 can have terminals formed on its upper surface corresponding to the electrode leads 26 of the cells 24 it houses. Thus, the cell assembly 20 housing the rectangular cells 24 can have external terminals electrically connected to the cell stack 25, which are provided on a module frame 22 located above the cell stack 25.

[0010] The cell assembly 20 that houses the above-mentioned rectangular cell 24 does not have any configurations such as an end plate 21 added by electrode leads 26 provided on the side, as shown in Figure 2.

[0011] The cell assemblies 20 differ slightly in the configuration of the cells 24 housed inside, as shown in Figures 1 and 2 above, but are the same in that the internal cell stack 25 is surrounded and protected by the module frame 22.

[0012] Cell assemblies 20 used in products requiring high power output, such as electric vehicles, can be connected in series and / or parallel by two or more of them to form higher-level devices such as battery packs.

[0013] Figure 3 shows a conventional battery pack and the cell assemblies 20 housed within it. In the case of a battery pack, it may include a pack case 10 into which the cell assemblies 20 are directly inserted and housed, and an upper case that connects to the pack case 10 so that the internal space of the pack case 10 can be isolated from the outside. Each of the cell assemblies 20 is housed in a partitioned space inside the pack case 10, as shown in Figure 3.

[0014] On the other hand, in a cell assembly 20 containing multiple cells 24 densely packed together in a narrow space, problems such as short circuits may occur in some of the cells 24, causing a sustained rise in temperature, which can lead to a thermal runaway phenomenon where the temperature of the cells 24 exceeds the critical temperature. High-temperature gas and spark particles may be ejected from the thermally runaway cells 24. (Here, spark particles refer to active material or molten aluminum particles detached from electrodes inside the cells 24.) Furthermore, in some cases, flames may be generated in some of the cells 24.

[0015] As described above, if gas is generated inside the cell assembly 20 surrounded by the module frame 22 and end plate 21, there is a risk that the cell assembly 20 may explode due to the gas pressure, and such explosion may transfer flames and heat to other cell assemblies 20. Conventional cell assemblies 20 can have opening holes 23 formed therein that allow gas to be released in order to solve the explosion problem described above.

[0016] Figure 4 shows a conventional cell assembly 20 to which the opening holes 23 are applied. The cell assembly 20 to which the opening holes 23 are applied can quickly discharge the gas even if the internal cell 24 experiences thermal runaway and generates high-temperature gas, thereby preventing the generation of internal pressure.

[0017] However, when an opening hole 23 is formed in the cell assembly 20 as described above, a problem frequently occurred in which spark particles and flames generated in the cell 24 were transferred to other cell assemblies 20 through the opening hole 23. [Overview of the initiative] [Problems that the invention aims to solve]

[0018] Therefore, the present invention was devised to solve the above-mentioned problems, and aims to provide a battery pack with a structure that can effectively discharge gases generated internally to the outside in the event of thermal runaway.

[0019] Furthermore, the present invention aims to provide a battery pack with a structure that can delay the progression of thermal transfer to other cell assemblies even if a thermal runaway phenomenon occurs in any one of the cell assemblies housed inside.

[0020] Other objects and advantages of the present invention can be understood from the following description and will be more clearly seen from 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 as set forth in the claims. [Means for solving the problem]

[0021] According to the present invention, a battery pack is provided in which a cell assembly is housed.

[0022] The battery pack includes a pack case in which a cell assembly is placed, and an upper case that connects to the pack case so as to cover the upper part of the cell assembly placed inside the pack case, wherein the upper case includes a protrusion that pressurizes the upper part of the cell assembly placed in the pack case.

[0023] The 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.

[0024] The module frame may include an opening hole opened such that the internal cell stack is exposed to the outside.

[0025] The opening hole may be formed in any one shape of a circular shape and a polygonal shape.

[0026] The opening hole may be formed to extend along any one direction of the longitudinal direction and the width direction of the cell assembly.

[0027] The cell assembly may further include a protective sheet attached to a surface of the module frame to cover the opening hole.

[0028] The protruding portion of the upper case may be formed to correspond to a position where there is no opening hole of the cell assembly.

[0029] The opening hole may be formed on the module frame located at an upper portion of the cell assembly.

[0030] The protective sheet may have a porous structure including a plurality of voids that selectively allow gas to pass through.

[0031] The protective sheet may have a structure in which no void is formed so that gas does not pass through.

[0032] The protective sheet may have electrical insulating properties.

[0033] The protective sheet may have heat resistance and flame resistance.

[0034] The protruding portion may have a columnar shape with a flat end face.

[0035] The above-mentioned protrusion may have a downward-convex projection shape.

[0036] The above-mentioned protrusion can be formed extending along either the longitudinal direction or the width direction of the upper case. [Effects of the Invention]

[0037] According to the present invention, in a battery pack containing multiple cell assemblies, even if a thermal runaway phenomenon occurs in any one of the cell assemblies, it is possible to minimize the transfer of heat to adjacent cell assemblies and improve safety against explosion. [Brief explanation of the drawing]

[0038] [Figure 1] This shows a conventional cell assembly including pouch-type cells. [Figure 2] This shows a conventional cell assembly that includes rectangular cells. [Figure 3] This shows a conventional battery pack and the cell assembly housed within it. [Figure 4] This shows a conventional cell assembly. [Figure 5] This shows a battery pack according to the first embodiment of the present invention. [Figure 6] This shows the cell assembly of the present invention. [Figure 7] The protective sheet is shown separated from the cell assembly in Figure 6 above. [Figure 8] This is a perspective view of the bottom of the upper case. [Figure 9] In the battery pack shown in Figure 5 above, the upper case has been treated with concealed lines so that the protruding part is visible. [Figure 10] The image above shows the upper case and pack case joined together as shown in Figure 9. [Figure 11] This is a simplified cross-section of a battery pack with one of the cell assemblies installed. [Figure 12]The above Figure 11 shows the movement of gas generated in the cell stack when thermal runaway occurs in the battery pack. [Figure 13] This shows a battery pack according to a second embodiment of the present invention. [Figure 14] Figure 13 above shows the cell assembly that will be housed within it. [Figure 15] The protective sheet is shown separated from the cell assembly in Figure 14 above. [Figure 16] This shows a battery pack according to a third embodiment of the present invention. [Figure 17] This shows a battery pack according to a fourth embodiment of the present invention. [Modes for carrying out the invention]

[0039] Preferred embodiments of the present invention will now be described in detail with reference to the attached drawings. Before that, however, terms and words used herein and in the claims shall not be interpreted to be limited to their usual or dictionary meanings, but rather as meanings and concepts consistent with the technical idea of ​​the present invention, based on the principle that an inventor may appropriately define the concepts of terms in order to best describe his own invention.

[0040] Therefore, the embodiments described herein and the configurations shown in the drawings represent only one of the most preferred embodiments of the present invention and do not represent the entire technical concept of the present invention; there may be a variety of equivalents and modifications that can substitute for them at the time of filing.

[0041] Furthermore, in describing the present invention, if it is determined that a specific description of a related known configuration or function may obscure the gist of the present invention, such detailed description will be omitted.

[0042] Since embodiments of the present invention are provided to more fully explain the invention to an ordinary person, the shapes and sizes of components in the drawings may be exaggerated, omitted, or shown schematically for the sake of clarity. Accordingly, the sizes and proportions of each component do not fully reflect their actual sizes and proportions.

[0043] The present invention relates to a battery pack that houses a plurality of cell assemblies, characterized in that a protruding portion with a structure that pressurizes the upper part of the housed cell assemblies is applied.

[0044] Figures 5 to 12 relate to a battery pack according to the first embodiment of the present invention, Figures 13 to 15 relate to a battery pack according to the second embodiment of the present invention, Figure 16 relates to a battery pack according to the third embodiment of the present invention, and Figure 17 relates to a battery pack according to the fourth embodiment of the present invention.

[0045] Specific embodiments of the battery pack of the present invention will be described in detail below with reference to the attached drawings. For reference, the forward / backward and up / down / left / right directions used to specify relative positions in the following description are for the purpose of aiding the understanding of the invention, and unless otherwise defined, the directions shown in the drawings are used as the reference.

[0046] Furthermore, the cell assembly of the present invention may be in a form in which pouch-type cells are housed, as shown in Figure 1, or in a form in which rectangular cells are housed, as shown in Figure 2. However, for convenience, the description will focus on the form in which pouch-type cells are housed, as shown in Figure 1.

[0047] (First Embodiment) Figure 5 shows a battery pack according to the first embodiment of the present invention.

[0048] The above-described battery pack includes a pack case 100 in which a cell assembly 300 is installed, and an upper case 200 that connects to the pack case 100 so as to cover the upper part of the cell assembly 300 installed inside the pack case 100.

[0049] The cell assembly 300 housed in the battery pack of the present invention is characterized by having an opening hole 321 formed on one side and a protective sheet 340 covering the opening hole 321.

[0050] Figure 6 shows the cell assembly 300 of the present invention, and Figure 7 shows the cell assembly 300 of Figure 6 with the protective sheet 340 separated.

[0051] The cell assembly 300 includes a cell stack 310 containing multiple cells and a module frame 320 surrounding at least one side of the cell stack 310.

[0052] As shown in Figure 6, the cell assembly 300 may further include an end plate 330 on which external terminals are located that protect the cell stack 310 housed inside from external impacts and are electrically connected to the cell stack 310.

[0053] As shown in Figure 7, the module frame 320 includes a number of opening holes 321 that are opened so that the internal cell stack 310 is exposed to the outside.

[0054] The opening hole 321 is formed to prevent the cell assembly 300 from exploding when high-temperature gas g is generated due to thermal runaway of the housed cell stack 310, causing an increase in the gas g pressure inside the cell assembly 300. In other words, the opening hole 321 serves as a passage through which the gas g generated by the thermal runaway of the cell stack 310 escapes to the outside.

[0055] The above-mentioned opening hole 321 is formed on the module frame 320, which is located above the cell assembly 300 shown in Figure 7.

[0056] The opening hole 321 can be formed in either a circular or polygonal shape.

[0057] The cell assembly 300 of the present invention further includes a protective sheet 340 that is attached to the surface of the module frame 320 so as to cover the opening hole 321.

[0058] The protective sheet 340 covers one side of the module frame 320 in which the opening hole 321 is formed, and serves to restrict flames and spark particles from flying out through the opening hole 321. The protective sheet 340 also serves to restrict flames and gases from flowing into the opening holes 321 of other normal cell assemblies 300 when one of the housed cell assemblies 300 experiences thermal runaway and generates flames and gases.

[0059] The protective sheet 340 described above 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.

[0060] Furthermore, the protective sheet 340 preferably includes an electrically insulating material.

[0061] The protective sheet 340 may have a structure in which no voids are formed to prevent gas from passing through, or it may have a porous structure that includes multiple voids that selectively allow gas to pass through.

[0062] The protective sheet 340, which has a structure that does not form voids, is attached to the cell assembly to seal the opening holes. Therefore, in the case of a cell assembly 300 with the protective sheet 340 properly attached, gas and flames are less likely to pass through the opening holes 321.

[0063] The protective sheet 340 has a limit pressure at which it will not deform under external pressure, and may break when pressure exceeding this limit pressure is applied. For example, the protective sheet 340 sealing the opening hole 321 as described above may partially break to release gas and flame when the pressure inside the cell assembly 300 reaches the limit pressure range. In this case, a break line may be applied to the protective sheet 340 to intentionally open a desired portion first.

[0064] The protective sheet 340, with its voids, allows gas g generated by the thermal runaway of the cell to pass through, but prevents spark particles and other particles that may be generated along with gas g from passing through.

[0065] The pack case 100 includes a base plate 110 that supports the lower part 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 of the cell assembly 300.

[0066] Furthermore, the pack case 100 may include a cross beam 130 whose lower end is connected to the base plate 110 so as to partition the internal space.

[0067] Multiple cell assemblies 300 can be arranged and installed in the internal space of the pack case 100, which is partitioned by the cross beam 130 and the like, so as to be separated from each other. At this time, each cell assembly 300 is arranged so that the opening hole 321 and the protective sheet 340 are on the upper surface, as shown in Figure 5.

[0068] As shown in Figure 5, the upper case 200 is connected to the upper end of the side beam 120 of the pack case 100 so as to cover the upper part of the cell assembly 300 which is installed inside the pack case 100.

[0069] The protective sheet 340 can be attached to the surface of the module frame 320 by an adhesive or glue. However, if the pressure of gas g is very high and exceeds the adhesive force, it may peel off the module frame 320. In other words, when the pressure of gas g is high, the protective sheet 340 may peel off the surface of the module frame 320 and fail to perform its role in filtering spark particles and flames.

[0070] The battery pack of the present invention is characterized by the addition of a structure that can push the protective sheet 340 toward the module frame 320 in order to prevent the protective sheet 340 from being removed from the surface of the module frame 320 as described above.

[0071] Specifically, the upper case 200 includes a protrusion 210 that pressurizes the upper part of the cell assembly 300 placed in the pack case 100.

[0072] Figure 8 is a bottom perspective view of the upper case 200.

[0073] As shown in Figure 8 above, a number of protrusions 210 are formed at the lower end of the upper case 200.

[0074] Each of the above-mentioned protrusions 210 is columnar in shape with a flat end face and protrudes from the surface of the upper case 200 to a predetermined length.

[0075] In addition to the shape shown above, the protrusion 210 may also be a downward-facing projection. That is, the protrusion 210 may be any shape that can directly pressurize the upper part of the cell assembly 300.

[0076] Figure 9 shows the battery pack from Figure 5, but with the upper case 200 concealed so that the protruding portion 210 is visible.

[0077] The above-mentioned protrusions 210 are formed at positions corresponding to each of the above-mentioned cell assemblies 300.

[0078] Preferably, the protrusion 210 extends to such an extent that it can pressurize the upper part of each cell assembly 300 when the upper case 200 is fully coupled with the pack case 100. Therefore, the protective sheet 340 attached to the module frame 320 of the cell assembly 300 can be pressed against the lower end of the protrusion 210 and remain attached.

[0079] However, the opening hole 321 of the cell assembly 300 must not be completely blocked by the protrusion 210. If the protrusion 210 blocks the opening hole 321, the gas g inside the cell assembly 300 may not be able to be smoothly discharged in the event of thermal runaway of the cell, posing a risk of explosion.

[0080] Figure 10 shows the state in which the upper case 200 and the pack case 100 from Figure 9 are joined together.

[0081] As shown in Figure 10, the above-mentioned protrusion 210 is formed at the lower end of the upper case 200 so as to correspond to a position in the cell assembly 300 where there is no opening hole 321.

[0082] Figure 11 shows a simplified cross-section of a battery pack in which one of the cell assemblies 300 is installed.

[0083] As shown in Figure 11 above, each protrusion 210 formed at the lower end of the upper case 200 pressurizes the module frame 320 in the cell assembly 300 where the opening hole 321 is not located.

[0084] Figure 12 shows the movement of gas g generated in the cell stack 310 when thermal runaway occurs in the battery pack shown in Figure 11.

[0085] Referring to Figure 12 above, 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 multiple protrusions 210 interposed between the upper case 200 and the cell assembly 300, and can then be discharged to the outside.

[0086] The battery pack of the present invention further includes an exhaust hole (not shown) formed to communicate with the internal space so that gas g generated inside can be discharged to the outside.

[0087] Therefore, in the battery pack of the present invention, the high-temperature gas g discharged through the opening hole 321 of the cell assembly 300 can be discharged to the outside through the discharge hole.

[0088] The discharge hole may be formed on one side of the side beam 120 of the pack case 100, or on one side of the upper case 200.

[0089] (Second Embodiment) The shape of the opening hole 321 of the cell assembly 300 housed in the battery pack of the present invention may be slit-shaped. That is, the opening hole 321 may be in a form that extends elongated in any one direction.

[0090] Figure 13 shows a battery pack according to a second embodiment of the present invention, Figure 14 shows a cell assembly 300 housed in Figure 13, and Figure 15 shows the cell assembly 300 of Figure 14 with the protective sheet 340 separated.

[0091] According to Figures 13 to 15 above, the opening hole 321 is formed extending along the longitudinal direction d4 of the cell assembly 300.

[0092] In addition to the shape shown above, the opening hole 321 may also have a shape that extends along the width direction d3 of the cell assembly 300.

[0093] (Third real-time form) The protrusion 210 included in the battery pack of the present invention may be in a form that extends long in either one direction.

[0094] Figure 16 shows the upper case 200 included in the battery pack according to the third embodiment of the present invention.

[0095] As shown in Figure 16 above, the protrusion 210 is formed to extend along the width direction d1 of the battery pack. Although not shown, it is preferable that the opening hole 321 of the cell assembly 300 is also formed in a shape corresponding to the shape of the protrusion 210.

[0096] (Fourth Embodiment) The protrusion 210 included in the battery pack of the present invention may be in a form that extends long in either one direction.

[0097] Figure 17 shows the upper case 200 included in the battery pack according to the fourth embodiment of the present invention.

[0098] As shown in Figure 17 above, the protrusion 210 is formed to extend along the longitudinal direction d2 of the battery pack. Although not shown, it is preferable that the opening hole 321 of the cell assembly 300 is also formed in a shape corresponding to the shape of the protrusion 210.

[0099] The present invention has been described in more detail above through the drawings and embodiments. However, the configurations described in the drawings or embodiments described herein are merely one embodiment of the present invention and do not represent the entire technical concept of the present invention. Therefore, there may be various equivalents and modifications that can be substituted for them at the time of filing. [Explanation of symbols]

[0100] 10: (Conventional technology) Pack case 20: (Conventional Technology) Cell Assembly 21: (Conventional Technology) End Plate 22: (Conventional Technology) Module Frame 23: (Conventional technology) Opening hole 24: (Conventional technology) Cell 25: (Conventional Technology) Cell Stack 26: (Conventional Technology) Electrode Lead 100: Pack Case 110: Base plate 120: Side beam 130: Crossbeam 200: Upper case 210:Protrusion 300: Cell assembly 310: Cell stack 320: Module Frame 321: Opening Hall 330: End plate 340: Protective sheet g: gas d1: Width direction of the battery pack d2: Longitudinal direction of the battery pack d3: Width direction of the cell assembly d4: Longitudinal direction of the cell assembly

Claims

1. A battery pack in which a cell assembly is housed, A pack case in which the aforementioned cell assembly is placed, It includes an upper case that connects to the pack case so as to cover the upper part of the cell assembly which is placed inside the pack case, The upper case includes a protrusion that pressurizes the upper part of the cell assembly placed in the pack case, An opening hole is formed on the upper surface of the cell assembly, which serves as a passage for gas generated inside the cell assembly due to thermal runaway to escape to the outside, and the cell assembly is equipped with a protective sheet that covers the opening hole. The protective sheet serves to restrict flames and spark particles from flying out or flowing in through the opening hole. A battery pack in which the protective sheet is pressurized at the protruding portion so as to maintain a state in which it covers the opening hole.

2. The aforementioned cell assembly is A cell stack containing multiple cells, The battery pack according to claim 1, comprising a module frame surrounding at least one side of the cell stack.

3. The battery pack according to claim 2, wherein the module frame includes the opening hole which is opened so that the internal cell stack is exposed to the outside.

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

5. The battery pack according to claim 3, wherein the opening hole is formed extending along either the longitudinal direction or the width direction of the cell assembly.

6. The battery pack according to claim 3, wherein the protective sheet is attached to the surface of the module frame so as to cover the opening hole.

7. The battery pack according to any one of claims 3 to 6, wherein the protrusion of the upper case is formed to correspond to a position in the cell assembly where there is no opening hole.

8. The battery pack according to any one of claims 3 to 6, wherein the opening hole is formed on the module frame located on the upper part of the cell assembly.

9. The battery pack according to claim 6, wherein the protective sheet has a porous structure that includes a plurality of voids that selectively allow gas to pass through.

10. The battery pack according to claim 6, wherein the protective sheet has a structure that does not form voids so that gas cannot pass through.

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

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

13. The battery pack according to any one of claims 1 to 6, wherein the protruding portion is columnar in shape with a flat end face.

14. The battery pack according to any one of claims 1 to 6, wherein the protruding portion has a downwardly convex projection shape.

15. The battery pack according to any one of claims 1 to 6, wherein the protrusion is formed extending along either the longitudinal direction or the width direction of the upper case.

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