Battery pack

Abstract

According to exemplary embodiments, a battery pack is provided. The battery pack comprises: a pack housing including a base plate: a battery cell assembly, which is disposed on the pack housing and includes a plurality of battery cells; a thermal interface material (TIM) layer between the battery cell assembly and the pack housing; and tape between the TIM layer and the pack housing.

Description

battery pack

[0001] The present invention relates to a battery pack. This application claims the benefit of Korean Application No. 10-2023-0178456, filed December 11, 2023, and Korean Application No. 10-2024-0146032, filed October 23, 2024, which are incorporated herein by reference in their entirety.

[0002] Unlike primary batteries, secondary batteries can be charged and discharged multiple times. They are widely used as a power source for various wireless devices, including handsets, laptops, and cordless vacuum cleaners. Recently, improved energy density and economies of scale have dramatically reduced the per-unit manufacturing cost of secondary batteries. Furthermore, as the range of battery electric vehicles (BEVs) has increased to match that of fuel-powered vehicles, the primary use of secondary batteries is shifting from mobile devices to mobility.

[0003] The technological development trend for secondary batteries for mobility is improving energy density and safety. The safety of secondary batteries for mobility is crucial, as it directly impacts the lives of passengers. Safety in secondary batteries can be achieved through mechanical robustness, reliable electrical insulation, and delayed heat transfer in the event of thermal runaway.

[0004] The problem that the technical idea of ​​the present invention seeks to solve is to provide a battery pack that is easy to service after-sales.

[0005] According to exemplary embodiments of the present invention for solving the above-described problem, a battery pack is provided. The battery pack includes a pack housing including a base plate; a battery cell assembly disposed on the pack housing and including a plurality of battery cells; a TIM (Thermal Interface Material) layer between the battery cell assembly and the pack housing; and a tape between the TIM layer and the pack housing.

[0006] The pack housing includes a lower side wall protruding from the base plate, and a height of the lower side wall is less than a height of the battery cell assembly.

[0007] The lower side wall includes a slanted surface oblique to the mounting surface of the base plate.

[0008] The above inclined surface faces the battery cell assembly.

[0009] The battery pack includes a lead plate covering the battery cell assembly, and the lead plate includes an upper side wall facing the lower side wall.

[0010] The height of the upper side wall is greater than the height of the side wall.

[0011] The battery pack includes a lead plate covering the battery cell assembly, and the lead plate includes an upper side wall facing the base plate.

[0012] The height of the upper side wall is greater than the height of the battery cell assembly.

[0013] The above tape covers the above base plate.

[0014] The above tape is in contact with each of the base plate and the TIM layer.

[0015] The above TIM layer is spaced from the base plate.

[0016] The above battery cell assembly includes a cell block including a plurality of battery cells and cross beams spaced apart from each other with the cell blocks interposed therebetween.

[0017] The above cross beams are symmetrical with respect to the cell block.

[0018] Each of the above cross beams includes a step structure.

[0019] According to exemplary embodiments of the present invention, a battery pack includes a tape interposed between a TIM (Thermal Interface Material) layer and a base plate. By tensioning the tape, the adhesive strength of the TIM layer can be removed, allowing the battery cells to be separated and replaced when quality issues arise.

[0020] The effects that can be obtained from the exemplary embodiments of the present invention are not limited to the effects mentioned above, and other effects not mentioned can be clearly derived and understood by those skilled in the art to which the exemplary embodiments of the present disclosure pertain from the following description. In other words, unintended effects resulting from practicing 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.

[0021] FIG. 1 is a plan view illustrating a battery pack according to exemplary embodiments.

[0022] Figure 2 is a cross-sectional view taken along the cutting line 1I-1I' of Figure 1.

[0023] Figure 3 is a cross-sectional view taken along the cutting line 1II-1II' of Figure 1.

[0024] FIG. 4 is a drawing for explaining a method according to exemplary embodiments.

[0025] Figure 5 is a cross-sectional view illustrating a method according to exemplary embodiments.

[0026] FIG. 6 is a cross-sectional view illustrating a battery pack according to other exemplary embodiments.

[0027] 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 concepts of terms to best explain his or her invention, they should be interpreted in a way that aligns with the technical spirit of the present invention.

[0028] Accordingly, 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. Therefore, it should be understood that there may be various equivalents and modified examples that can replace them at the time of filing this application.

[0029] 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.

[0030] 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.

[0031]

[0032] (Example 1)

[0033] FIG. 1 is a plan view showing a battery pack (100) according to exemplary embodiments.

[0034] Figure 2 is a cross-sectional view taken along the cutting line 1I-1I' of Figure 1.

[0035] Figure 3 is a cross-sectional view taken along the cutting line 1II-1II' of Figure 1.

[0036] Referring to FIGS. 1 and 2, a battery pack (100) may include a pack housing (110), a plurality of battery cell assemblies (120), a center beam (131), supporting beams (133, 135), tapes (141), TIM (Thermal Interface Material) layers (143), a lead (150), a gasket (160), and bolts (170). The battery pack (100) may be a final product mounted in an application such as a vehicle.

[0037] The pack housing (110) can provide a space for mounting battery cell assemblies (120). The pack housing (110) can include a base plate (111) and side walls (112, 113, 114, 115).

[0038] Here, two directions substantially parallel to the mounting surface (111M) of the base plate (111) (i.e., the surface facing the battery cell assembly (120)) are defined as the X direction and the Y direction, and a direction substantially perpendicular to the upper surface of the base plate (111) is defined as the Z direction. The X direction, the Y direction, and the Z direction may be substantially perpendicular to each other.

[0039] The base plate (111) and the side walls (112, 113) may each be provided by an extrusion process. The extrusion direction of the base plate (111) and the side walls (112, 113) may be the X direction. The side walls (114, 115) may also be provided by an extrusion process.

[0040] According to exemplary embodiments, the base plate (111) and side walls (112, 113) may be joined by friction stir welding. The base plate (111) may include a plurality of plates joined by friction stir welding.

[0041] The base plate (111) may include a plurality of cooling channels (CH). The plurality of cooling channels (CH) may provide passages for the movement of a refrigerant, such as water, for example. The plurality of cooling channels (CH) may be formed by an extrusion process. The plurality of cooling channels (CH) may extend in the X direction. The plurality of cooling channels (CH) may be spaced apart in the Y direction. In Fig. 3, the plurality of cooling channels (CH) having a circular cross-section are illustrated, but this is for illustrative purposes only and does not limit the technical idea of ​​the present invention in any way. Each of the plurality of cooling channels may have various shapes, such as a rectangular shape, an oval shape, etc.

[0042] A plurality of battery cell assemblies (120) may be arranged on a base plate (111) of a pack housing (110). The base plate (111) may support the plurality of battery cell assemblies (120). Side walls (112, 113, 114, 115) may horizontally surround the plurality of battery cell assemblies (120). The side walls (112, 113, 114, 115) may protect the plurality of battery cell assemblies (120).

[0043] For example, the battery pack (100) may be of a modular type, and each of the plurality of battery cell assemblies (120) may not include a module frame. As another example, the battery pack (100) may be of a modular type, and each of the plurality of battery cell assemblies (120) may include a module frame.

[0044] A plurality of battery cell assemblies (120) may be arranged on a base plate (111). Each of the plurality of battery cell assemblies (120) may include a cell block (121) and cross beams (125).

[0045] A cell block (121) may include a plurality of battery cells. The plurality of battery cells of the cell block (121) may form a plurality of banks. Each of the plurality of banks may include one or more parallel-connected battery cells. The plurality of banks may be connected to each other in series. The number of series-connected banks and the number of parallel-connected battery cells may be determined according to the magnitude of voltage and current to be output from each of the battery cell assemblies (120).

[0046] Here, a plurality of battery cells are the basic units of a lithium-ion battery, i.e., a secondary battery. Each of the plurality of battery cells includes an electrode assembly, an electrolyte, and a case. Each of the plurality of battery cells may be any one of a cylindrical battery cell, a prismatic battery cell, and a pouch-type battery cell. The electrode assembly of the cylindrical battery cell is housed in a cylindrical metal can. The electrode assembly of the prismatic battery cell is housed in a prismatic metal can. The electrode assembly of the pouch-type battery cell is housed in a pouch case including an aluminum laminate sheet.

[0047] The electrode assembly may include an anode, a cathode, and a separator interposed between the anode and the cathode. The electrode assembly may be either a jelly-roll type or a stack type. The jelly-roll type electrode assembly may include a winding structure of the anode, the cathode, and the separator interposed therebetween. The stack type electrode assembly may include a plurality of sequentially stacked anodes, a plurality of cathodes, and a plurality of separators interposed therebetween.

[0048] The cross beams (125) may be spaced apart from each other with the cell block (121) therebetween. The cross beams (125) may have the same shape. The cross beams (125) may be arranged symmetrically around the cell block (121). The cross beams (125) may be provided, for example, by an extrusion process, but are not limited thereto.

[0049] The cross beams (125) may include a step structure. The step structure of the cross beams (125) may be used for connection with the supporting beams (133, 135). The cross beams (125) may be connected to the supporting beams (133, 135) by a method such as bolting.

[0050] TIM layers (143) may be provided on the base plate (111B) of the pack housing (110). The TIM layers (143) may be interposed between each of the plurality of battery cell assemblies (120) and the base plate (111). The TIM layers (143) may include a resin composition. The TIM layers (143) may be provided by a thermal resin application process.

[0051] In the example of FIG. 3, there are no TIM layers (143) at the center of the Y direction of each of the plurality of battery cell assemblies (120), and two TIM layers (143) are shown corresponding to each of the plurality of battery cell assemblies (120) (i.e., overlapping in the Z direction), but this is for illustration only and does not limit the technical idea of ​​the present invention in any sense.

[0052] The resin composition may be a room temperature curable composition. That is, the curing reaction of the resin composition may be initiated and proceed at room temperature. The curing reaction of the resin composition may be accelerated at a temperature higher than room temperature. The curing reaction rate of the resin composition at a temperature higher than room temperature may be faster than the curing reaction rate of the resin composition at room temperature. As a non-limiting example, the subject of the resin composition may be any one of a silicone resin, a polyol resin, an epoxy resin, and an acrylic resin.

[0053] The curing agent of the resin composition may be selected depending on the subject matter of the resin composition. For example, if the subject matter of the resin composition is a silicone resin, the curing agent may be a siloxane compound. If the subject matter of the resin composition is a polyol resin, the curing agent may use an isocyanate compound. If the subject matter of the resin composition is an epoxy resin, the curing agent may use an amine compound. If the subject matter of the resin composition is an acrylic resin, the curing agent may be an isocyanate compound.

[0054] The inorganic filler of the resin composition may have relatively high thermal conductivity. According to exemplary embodiments, the thermal conductivity of the inorganic filler of the resin composition may be about 1 W / mK or more. According to exemplary embodiments, the thermal conductivity of the inorganic filler of the resin composition may be about 5 W / mK or more. According to exemplary embodiments, the thermal conductivity of the inorganic filler of the resin composition may be about 10 W / mK or more. According to exemplary embodiments, the thermal conductivity of the inorganic filler of the resin composition may be about 15 W / mK or more.

[0055] According to exemplary embodiments, the inorganic filler of the resin composition may include a ceramic. For example, the inorganic filler of the resin composition may include any one of aluminum oxide (Al2O3), aluminum nitride (AlN), boron nitride (BN), silicon nitride (Si3N4), silicon carbide (SiC), beryllium oxide (BeO), zinc oxide (ZnO), aluminum hydroxide (Al(OH)3), and boehmite. The resin composition may also include a carbon filler. For example, the resin composition may include any one of fumed silica, clay, and calcium carbonate.

[0056] Tapes (141) may be interposed between the TIM layers (143) and the base plate (111). The tapes (141) may contact each of the TIM layers (143) and the base plate (111). The thermal conductivity of each of the tapes (141) may be in the range of about 1 W / m·K to about 5 W / m·K. Each of the tapes (141) may include a flexible material.

[0057] The tapes (141) may cover the base plate (111), and thus, each of the TIM layers (143) may not be in contact with the base plate (111). Each of the TIM layers (143) may be spaced apart from the base plate (111).

[0058] The battery cell assemblies (120) may partially cover the tapes (141). The battery cell assemblies (120) may expose portions of the tapes (141). The tapes (141) may protrude in the Y direction with respect to the battery cell assemblies (120). The tapes (141) may include a portion interposed between the battery cell assemblies (120) and the side wall (112) or a portion interposed between the battery cell assemblies (120) and the side wall (113).

[0059] The TIM layers (143) may partially cover the tapes (141). The TIM layers (143) may expose portions of the tapes (141). The tapes (141) may protrude in the Y direction with respect to the TIM layers (143). The tapes (141) may include a portion interposed between the TIM layer (143) and the sidewall (112) or a portion interposed between the TIM layer (143) and the sidewall (113).

[0060] A center beam (131) may be interposed between a plurality of battery cell assemblies (120). The center beam (131) may extend in the X direction. The center beam (131) may isolate the plurality of battery cell assemblies (120) in the Y direction. According to exemplary embodiments, the center beam (131) may be provided separately from the base plate (111) and welded to the base plate (111). According to other exemplary embodiments, the center beam (131) may form an integral element continuous with the base plate (111).

[0061] Supporting beams (133, 135) can be joined to the base plate (111) by a method such as welding. The supporting beams (133) can be interposed between the supporting beams (135). The supporting beams (133) can be interposed between the battery cell assemblies (120). The supporting beams (135) can be interposed between the battery cell assemblies (120) and the side wall (114) or between the battery cell assemblies (120) and the side wall (115).

[0062] The supporting beams (133) can be in contact with two cross beams (125), and the supporting beams (135) can be in contact with one cross beam (125). Accordingly, the thickness of each of the supporting beams (133) can be different from the thickness of each of the supporting beams (135). Accordingly, the thickness of each of the supporting beams (133) can be greater than the thickness of each of the supporting beams (135).

[0063] In Fig. 1, the arrangement of the plurality of battery cell assemblies (120) can be referred to as a 2 * 2 arrangement. The arrangement of the center beam (131), the supporting beams (133, 135) and the plurality of battery cell assemblies (120) disclosed in Fig. 1 is a non-limiting example and does not limit the technical idea of ​​the present invention in any sense. A person skilled in the art will be able to easily arrive at a plurality of battery cell assemblies (120) arranged in an M * N configuration (wherein, M and N are each integers greater than or equal to 2) based on the description herein.

[0064] The lead (150) can be coupled to the pack housing. The lead (150) can be coupled to the side walls (112, 113, 114, 115). The lead (150) can cover elements mounted inside the battery pack (100), such as battery cell assemblies (120) and electrical components. The lead (150) can be fixed to the pack housing (110) by a mechanical coupling means, such as bolting. The lead (150) can be fixed to the side walls (112, 113, 114, 115) by a mechanical coupling means, such as bolting.

[0065] The lid (150) may include a ceiling portion (151) and side walls (152, 153). The ceiling portion (151) may be spaced apart from the base plate (111) with a plurality of battery cell assemblies (120) therebetween. The ceiling portion (151) may be approximately parallel to the base plate (111). The side wall (152) may face the side wall (112), and the side wall (153) may face the side wall (113). Each of the side walls (152, 153) of the lid (150) may be referred to as an upper side wall, and each of the side walls (112, 113) of the pack housing (110) may be referred to as a lower side wall.

[0066] A gasket (160) may be interposed between the side walls (112, 113, 114, 115) and the side walls (152, 153). The gasket (160) may include a compressible material such as EPDM (Ethylene-Propylene Diene Monomer). The gasket (160) may be pressed by the side walls (112, 113, 114, 115) and the side walls (152, 153), thereby providing liquid-tightness of the pack housing (100).

[0067] Bolts (170) can secure the side walls (112, 113) and the side walls (152, 153) to each other. Bolts (170) can be fastened to each of the side walls (112, 113) and the side walls (152, 153). Each of the bolts (170) can include a flange and a cylindrical portion. The flange of each of the bolts (170) can be in contact with the base plate (111).

[0068] The height of each of the side walls (112, 113) may be smaller than the height of each of the battery cell assemblies (120). The height of each of the side walls (112, 113) of the pack housing (110) may be different from the height of each of the side walls (152, 153) of the lid (150). The height of each of the side walls (112, 113) of the pack housing (110) may be smaller than the height of each of the side walls (152, 153) of the lid (150). The sum of the height of each of the side walls (112, 113) and the height of each of the side walls (152, 153) of the lid (150) may be larger than the height of each of the battery cell assemblies (120).

[0069] The side wall (112) may include an inclined surface (112S), and the side wall (113) may include an inclined surface (113S). Each of the inclined surfaces (112S, 113S) may be slanted to the mounting surface (111M) of the base plate (111). Each of the inclined surfaces (112S, 113S) may face the battery cell assemblies (120).

[0070] The battery pack may further include exhaust devices coupled to either the side walls (114, 115) or the lid (150). Either the side walls (114, 115) or the lid (150) may include exhaust holes connected to the exhaust devices. The exhaust devices may be configured to delay thermal propagation by releasing high-temperature gases inside the battery pack (100) to the outside when a thermal runway event occurs in the plurality of battery cell assemblies (120).

[0071] Here, thermal runaway of multiple battery cell assemblies (120) is a state in which temperature changes of multiple battery cell assemblies (120) further accelerate the temperature change, which is an uncontrollable positive feedback. Multiple battery cell assemblies (120) in a state of thermal runaway exhibit a rapid temperature increase and emit a large amount of high-pressure gas and combustion debris.

[0072] The battery pack (100) may further include a Battery Management System (BMS). The BMS may be configured to monitor, balance, and control the battery pack (100). Monitoring of the battery pack (100) may include measuring voltage and current of specific nodes within a plurality of battery cell assemblies (120) and measuring temperature of set locations within the battery pack (100). The battery pack (100) may include measuring instruments for measuring the voltage, current, and temperature described above.

[0073] Balancing of a battery pack (100) is an operation that reduces the deviation between multiple battery cell assemblies (120). Control of the battery pack (100) includes preventing overcharge, overdischarge, and overcurrent. Through monitoring, balancing, and control, the battery pack (100) can operate under optimal conditions, thereby preventing shortening of the lifespan of each of the multiple battery cell assemblies (120).

[0074] The battery pack (100) may further include additional electrical components, such as a cooling device, a PRA (Power Relay Assembly), and a safety plug. The cooling device may include a cooling fan. The cooling fan may prevent overheating of each of the plurality of battery cell assemblies (120) by circulating air inside the battery pack (100). The PRA may be configured to supply or cut off power from the high-voltage battery to an external load (e.g., a vehicle motor). The PRA may protect the plurality of battery cell assemblies (120) and the external load (e.g., a vehicle motor) by cutting off power supply to the external load (e.g., a vehicle motor) in a situation where an abnormal voltage, such as a voltage surge, occurs.

[0075] The battery pack (100) may further include a plurality of bus bars configured to electrically connect a plurality of battery cell assemblies (120). The plurality of battery cell assemblies (120) may be connected in series by the plurality of bus bars. Accordingly, the battery pack (100) may be configured to output a high voltage to an external load (e.g., a vehicle motor).

[0076]

[0077] (Example 2)

[0078] FIG. 4 is a drawing for explaining a method according to exemplary embodiments.

[0079] Figure 5 is a cross-sectional view illustrating a method according to exemplary embodiments.

[0080] Referring to FIGS. 3 to 5, at P110, the lead (150) can be separated from the pack housing (110).

[0081] Next, at P120, the tape (141) can be removed. In this process, the tapes (141) that overlap with the problematic battery cell assembly (120) in the Z direction can be removed. The tape (141) can be removed by tension. The tape (141) can have sufficient tensile strength so that it does not break while the tape (141) is removed. According to exemplary embodiments, in addition to the height of the side walls (112, 113) being sufficiently low, the side walls (112, 113) include inclined surfaces (112S, 113S), so that the angle between the tension direction of the tape (141) and the main surface of the tape (141) (or the mounting surface (111M) of the base plate (111)) can be sufficiently small. Accordingly, the tape (141) can be prevented from breaking while being tensioned.

[0082] Since the TIM layers (143) are already cured during the assembly stage of the battery pack (100), if the tape (141) is removed, there may be no adhesion between the TIM layers (143) and the base plate (111). Accordingly, in P130, the problematic battery cell assembly (120) can be replaced with a normal battery cell assembly.

[0083]

[0084] (Example 3)

[0085] Fig. 6 is a cross-sectional view illustrating a battery pack (101) according to other exemplary embodiments. More specifically, Fig. 6 shows a portion corresponding to Fig. 3.

[0086] Referring to FIG. 6, a battery pack (101) may include a pack housing (110'), a plurality of battery cell assemblies (120), a center beam (131), supporting beams (133, 135, see FIG. 2), tapes (141), TIM layers (143), a lead (150'), a gasket (160), and bolts (170). The battery pack (101) may be a final product mounted in an application such as a vehicle.

[0087] The plurality of battery cell assemblies (120), the center beam (131), the supporting beams (133, 135, see FIG. 2), the tapes (141) and the TIM layers (143) are substantially the same as those described with reference to FIGS. 1 to 3, so a duplicate description thereof is omitted.

[0088] The pack housing (110') may not include side walls (112, 113, see FIG. 2). The lid (150') may include a ceiling portion (151) and side walls (152', 153'), which may be in contact with the base plate (111). The height of each of the side walls (152', 153') may be greater than the height of each of the battery cell assemblies (120).

[0089] Each of the side walls (152', 153') may face the base plate (111). A gasket (160) may be interposed between the side walls (152', 153') and the base plate (111). Bolts (170) may secure the base plate (111) and the side walls (152', 153') to each other. The bolts (170) may be fastened to the base plate (111) and the side walls (152', 153'), respectively.

[0090]

[0091] 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.

Claims

1. Pack housing including base plate; A battery cell assembly disposed on the pack housing and including a plurality of battery cells; A TIM (Thermal Interface Material) layer between the battery cell assembly and the pack housing; and A battery pack comprising a tape between the TIM layer and the pack housing.

2. In paragraph 1, The above pack housing includes a lower side wall protruding from the base plate, and A battery pack, characterized in that the height of the lower side wall is smaller than the height of the battery cell assembly.

3. In paragraph 2, A battery pack, characterized in that the lower side wall includes an inclined surface oblique to the mounting surface of the base plate.

4. In paragraph 3, A battery pack, characterized in that the inclined surface faces the battery cell assembly.

5. In paragraph 2, Further comprising a lead plate covering the above battery cell assembly, and A battery pack, characterized in that the lead plate includes an upper side wall facing the lower side wall.

6. In paragraph 5, A battery pack, characterized in that the height of the upper side wall is greater than the height of the lower side wall.

7. In paragraph 1, Further comprising a lead plate covering the above battery cell assembly, and A battery pack, characterized in that the lead plate includes an upper side wall facing the base plate.

8. In paragraph 7, A battery pack, characterized in that the height of the upper side wall is greater than the height of the battery cell assembly.

9. In paragraph 1, A battery pack characterized in that the above tape covers the above base plate.

10. In paragraph 1, A battery pack, characterized in that the tape is in contact with each of the base plate and the TIM layer.

11. In paragraph 1, A battery pack, characterized in that the TIM layer is spaced apart from the base plate.

12. In paragraph 1, A battery pack characterized in that the battery cell assembly includes a cell block including a plurality of battery cells and cross beams spaced apart from each other with the cell blocks interposed therebetween.

13. In paragraph 12, A battery pack, wherein the cross beams are symmetrical with respect to the cell block.

14. In paragraph 12, A battery pack, wherein each of the above cross beams includes a step structure.

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