Battery cell assembly and battery pack

Abstract

According to exemplary embodiments of the present invention for solving the described problem, a battery cell assembly is provided. The battery cell assembly comprises: a plurality of battery cells arranged in a first direction; and a refractory structure disposed on the plurality of battery cells, wherein the refractory structure is in contact with each of the plurality of battery cells and is structurally corrugated.

Description

Battery cell assemblies and battery packs

[0001] The present invention relates to a battery cell assembly and a battery pack. This application claims the benefit of Korean Application No. 10-2024-0010483, filed January 23, 2024, and Korean Application No. 10-2024-0031042, filed March 5, 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 technical idea of ​​the present invention aims to solve a problem by providing a battery cell assembly and battery pack with improved safety.

[0005] According to exemplary embodiments of the present invention for solving the above-described problem, a battery cell assembly is provided. The battery cell assembly includes a plurality of battery cells arranged in a first direction; a refractory structure disposed on the plurality of battery cells, wherein the refractory structure contacts each of the plurality of battery cells and has a wrinkled structure.

[0006] The above wrinkled structure includes first wrinkles and second wrinkles arranged along a first direction, and the shapes of the first wrinkles and the second wrinkles are different.

[0007] The first wrinkle includes a first slope oblique to the first direction and a second slope oblique to the first direction, and the second wrinkle includes a third slope oblique to the first direction and a fourth slope oblique to the first direction.

[0008] The magnitude of the first slope of the first slope is different from the magnitude of the second slope of the second slope.

[0009] The magnitude of the first slope is smaller than the magnitude of the second slope.

[0010] The magnitude of the third slope of the third slope is different from the magnitude of the fourth slope of the fourth slope.

[0011] The magnitude of the third slope is smaller than the magnitude of the fourth slope.

[0012] The magnitude of the third slope is the same as the magnitude of the first slope of the first slope.

[0013] The magnitude of the fourth slope is the same as the magnitude of the second slope of the second slope.

[0014] The above refractory structure comprises multiple layers.

[0015] The above refractory structure comprises first to third layers, wherein the first layer is a refractory adhesive tape, the second layer comprises a refractory sheet, and the third layer comprises a refractory coating.

[0016] The second layer comprises one of PO (propylene oxide), PU (poly urethane), aramid film, NCG (non-combustible glass fiber sheet), and mPPO (modified polyphenylene oxide) containing glass fiber.

[0017] The third layer comprises ceramic.

[0018] The thickness of the third layer is greater than the thickness of the first layer.

[0019] The thickness of the third layer is greater than the thickness of the second layer.

[0020] The thickness of the third layer is 25 μm or more, and the thickness of the third layer is 30 μm or less.

[0021] The sum of the thicknesses of the first to third layers is 40 μm or more, and the sum of the thicknesses of each of the first to third layers is 50 μm or less.

[0022] According to exemplary embodiments of the present invention, a battery cell assembly may include a refractory cover. The refractory cover may have a corrugated structure, thereby improving the yield and throughput of the battery cell assembly assembly assembly process.

[0023] 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.

[0024] FIG. 1 is a perspective view illustrating a battery cell assembly according to exemplary embodiments.

[0025] Figure 2 is a cross-sectional view taken along the cutting line 1I-1I' of Figure 1.

[0026] Figure 3 is an enlarged partial cross-sectional view of a portion of Figure 2.

[0027] Figure 4 is a cross-sectional view showing a battery cell.

[0028] Figure 5 is an exploded perspective view of a battery cell.

[0029] Figure 6 is a cross-sectional view of the refractory structure.

[0030] Figure 7 is a cross-sectional view taken along the cutting line 6I-6I' of Figure 6.

[0031] FIG. 8 is a flowchart illustrating a method for manufacturing a secondary battery according to exemplary embodiments.

[0032] FIGS. 9 to 13 are flowcharts illustrating a method for manufacturing a secondary battery according to exemplary embodiments.

[0033] Figures 14 and 15 are cross-sectional views illustrating a refractory structure according to other exemplary embodiments.

[0034] FIG. 16 is a plan view illustrating a battery pack according to exemplary embodiments.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039]

[0040] (Example 1)

[0041] FIG. 1 is a perspective view illustrating a battery cell assembly (120) according to exemplary embodiments.

[0042] Figure 2 is a cross-sectional view taken along the cutting line 1I-1I' of Figure 1.

[0043] Figure 3 is an enlarged partial cross-sectional view of a portion (POR) of Figure 2.

[0044] Figure 4 is a cross-sectional view showing a battery cell (121).

[0045] Figure 5 is an exploded perspective view of a battery cell (121).

[0046] Figure 6 is a cross-sectional view of a refractory structure (128).

[0047] Figure 7 is a cross-sectional view taken along the cutting line 6I-6I' of Figure 6.

[0048] Referring to FIGS. 1 to 3, a battery cell assembly (120) may include a plurality of battery cells (121), pads (122), a first integrated circuit assembly (123), a second integrated circuit assembly (124), an FFC (Flexible Flat Cable) assembly (127), and a refractory structure (128).

[0049] Referring to FIGS. 4 and 5, a battery cell (121) may include a cell case (121C), an electrode assembly (121EA), a positive terminal (121P), and a negative terminal (121N). The battery cell (121) may further include an electrolyte.

[0050] According to exemplary embodiments, the battery cell (121) may include 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. Hereinafter, the technical idea of ​​the present invention will be described based on an example in which the battery cell (121) is a pouch-type battery cell. However, a person skilled in the art will easily arrive at an example in which the battery cell (121) is one of a cylindrical battery cell and a prismatic battery cell based on the description herein.

[0051] The electrode assembly (121EA) may include a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode. The electrode assembly (121EA) may be either a jelly-roll type or a stack type. The jelly-roll type electrode assembly (121EA) may include a winding structure of a positive electrode, a negative electrode, and a separator interposed between them. The stack type electrode assembly (121EA) may include a plurality of sequentially stacked positive electrodes, a plurality of negative electrodes, and a plurality of separators interposed between them.

[0052] Each of the plurality of anodes of the electrode assembly (121EA) may include an anode tab (not shown). The anode tab (not shown) of each of the plurality of anodes of the electrode assembly (121EA) may be short-circuited with the anode terminal (121P). The anode tab (not shown) of each of the plurality of anodes of the electrode assembly (121EA) may be welded with the anode terminal (121P).

[0053] Each of the plurality of cathodes of the electrode assembly (121EA) may include a cathode tab (121NT). The cathode tab (121NT) of each of the plurality of cathodes of the electrode assembly (121EA) may be short-circuited with the cathode terminal (121N). The cathode tab (121NT) of each of the plurality of cathodes of the electrode assembly (121EA) may be welded with the cathode terminal (121N).

[0054] The cell case (121C) may include an inner resin layer, a metal layer, and an outer resin layer. An adhesive and a corrosion-preventing layer may further be provided between the inner resin layer and the metal layer and between the outer resin layer and the metal layer.

[0055] The inner resin layer may have heat-sealing properties and may be referred to as a sealant layer. The inner resin layer enables sealing of the cell case (121C). The inner resin layer may include a polyolefin-based resin, such as polypropylene (PP) and polyethylene (PE). The metal layer may include one of an alloy of iron, carbon, chromium, and manganese, an alloy of iron, chromium, and nickel, and aluminum. The metal layer may be a gas barrier. The metal layer may block the ingress and egress of gas from the cell case (121C). The outer resin layer may be a surface protection layer. The outer resin layer may include a material having wear resistance and heat resistance, such as a nylon resin.

[0056] The cell case (121C) may be provided by joining a first cell case (121C1) and a second cell case (121C2). The first cell case (121C1) may be substantially flat. The first cell case (121C1) may not include a receiving portion. The second cell case (121C2) may include a receiving portion (121R). The receiving portion (121R) may be formed by a pouch forming process. The receiving portion (121R) is a portion of the second cell case (121C2) formed into a bowl shape to receive the electrode assembly (121EA).

[0057] The terrace (121T) of the second cell case (121C2) may surround the receiving portion (121R). The terrace (121T) of the second cell case (121C2) may be joined to the edge of the first cell case (121C1), thereby providing a cell case (121C). The sealing portion (121CS) may be provided by joining the first and second cases (121C1, 121C2). That is, the sealing portion (121CS) may be a joining portion of the first and second cases (121C1, 121C2).

[0058] As in the example of Fig. 2, when the receiving portion is formed only in the second cell case (121C2) among the first and second cases (121C1, 121C2), the sealing portion (121CS) may be connected to the first main surface (121FS1). The sealing portion (121CS) may include a portion that forms a plane with the first main surface (121FS1).

[0059] The cell case (121C) may have an approximately rectangular parallelepiped shape, and the first main surface (121FS1) and the second main surface (121FS2) of the cell case (121C) may be widest surfaces of the cell case (121C). The first main surface (121FS1) and the second main surface (121FS2) may be substantially parallel to at least one of the electrode assembly (121EA) or the plurality of positive electrodes and the plurality of negative electrodes included in the electrode assembly (121EA). The first main surface (121FS1) and the second main surface (121FS2) may be opposite to each other. The first main surface (121FS1) and the second main surface (121FS2) may be substantially perpendicular to the X direction, but are not limited thereto.

[0060] An insulating tape (121I) may be applied on the positive terminal (121P) and the negative terminal (121N). The positive terminal (121P) and the negative terminal (121N) may protrude outside the cell case (121C). The positive terminal (121P) and the negative terminal (121N) may protrude in the Y direction from the cell case (121C). Accordingly, the resulting voltage and current of the battery cell (121) may be output through the positive terminal (121P) and the negative terminal (121N). The positive terminal (121P) may be a positive lead. The negative terminal (121N) may be a negative lead. The Y direction may be substantially perpendicular to the X direction.

[0061] Referring again to FIGS. 1 to 3, a plurality of battery cells (121) may be arranged in the X direction. The plurality of battery cells (121) may be joined by, for example, an adhesive.

[0062] A plurality of battery cells (121) may form a plurality of banks (BNK). For example, some (e.g., three) battery cells (121) may be connected in parallel to each other and form a bank (BNK). The plurality of banks (BNK) may be connected in series. The resulting connection configuration of the plurality of battery cells (121) may be referred to as 3-parallel-16-series (3P-16S), but this is for illustrative purposes only and does not limit the technical spirit of the present invention in any way. The number of banks connected in series and the number of battery cells (121) included in the plurality of banks may be determined depending on the magnitude of voltage and current to be output from the battery cell assembly (120).

[0063] In this example, two banks (BNK) can form a unit stack (US). The unit stacks (US) can alternate with the pads (122). One of the pads (122) can be placed between two of the unit stacks (US), and one of the unit stacks (US) can be placed between two of the pads (122).

[0064] Since the odd-numbered banks (BNK) are connected in series with the even-numbered banks (BNK), the orientation of the battery cells (121) of the odd-numbered banks (BNK) may be different from the orientation of the battery cells (121) of the even-numbered banks (BNK). The orientation of the battery cells (121) of the odd-numbered banks (BNK) may be opposite to the orientation of the battery cells (121) of the even-numbered banks (BNK). That is, the orientation of the battery cells (121) of the odd-numbered banks (BNK) rotated 180 degrees around the Z-axis may be the same as the orientation of the battery cells (121) of the even-numbered banks (BNK). Accordingly, the positive terminals (121P, see FIG. 5) of the battery cells (121) of the odd-numbered banks (BNK) may be adjacent to the negative terminals (121N, see FIG. 5) of the battery cells (121) of the even-numbered banks (BNK), and the positive terminals (121P, see FIG. 5) of the battery cells (121) of the even-numbered banks (BNK) may be adjacent to the negative terminals (121N, see FIG. 5) of the battery cells (121) of the odd-numbered banks (BNK).

[0065] The pads (122) can absorb swelling of the plurality of battery cells (121). Each of the pads (122) can include polyurethane (PU). Each of the pads (122) can include a refractory material such as silicone. As a non-limiting example, two of the banks (BNK) can be interposed between adjacent pads (122).

[0066] The first integrated circuit assembly (123) may include an insulating frame, an integrated circuit, bus bars, sensing plates, sensing bars, temperature sensors, wiring, and an insulating cover. The second integrated circuit assembly (124) may include an insulating frame, an integrated circuit, sensing plates, temperature sensors, wiring, and an insulating cover.

[0067] The first and second integrated circuit assemblies (123, 124) may include physical and functional components for providing electrical connections between the plurality of battery cells (121), outputting the resulting voltages of the plurality of battery cells (121), and measuring voltages (or currents) of nodes within a circuit comprised of the plurality of battery cells (121).

[0068] The insulating frame may include an insulating material such as plastic. The insulating frame may cover the front of a plurality of battery cells (121). The insulating frame may support integrated circuits, bus bars, sensing plates, sensing bars, temperature sensors, and wiring.

[0069] The bus bars may be short-circuited to the positive leads (121P) of one or more battery cells (121) of a first bank (BNK) and to the negative leads (121N) of one or more battery cells (121) of a last bank (BNK). The bus bars may be welded to the positive leads (121P) of one or more battery cells (121) of the first bank (BNK) and to the negative leads (121N) of one or more battery cells (121) of the last bank (BNK). The resulting voltage of the plurality of battery cells (121) of the battery cell assembly (120) may be output through the bus bars. The bus bars may be fixed to an insulating frame.

[0070] The integrated circuit may be mounted on an insulating frame. The positive leads (121P) and negative leads (121N) welded to each other may form nodes within the battery cell assembly (120). The integrated circuit may be configured to measure the voltages of the nodes via sensing plates and sensing bars.

[0071] The sensing bars may include a conductive material. The sensing bars may have a rod-like shape. The sensing bars may be short-circuited to the bus bars. The sensing bars may be coupled to the bus bars. The voltage of the bus bars may be measured through the sensing bars.

[0072] Each of the plurality of sensing plates may have a patch shape or a pad shape. The plurality of sensing plates may include a conductive material. The plurality of sensing plates may be short-circuited to corresponding ones of the positive lead (121P) and the negative lead (121N) of the plurality of battery cells (121).

[0073] Each of the plurality of sensing plates can be connected to an integrated circuit. Through the plurality of sensing plates, the voltages of the plurality of nodes within the battery cell assembly (120) can be measured.

[0074] The temperature sensors may be configured to measure the temperature of multiple points of the battery cell assembly (120). The temperature sensors may be spatially distributed, thereby allowing the temperature distribution within the battery cell assembly (120) to be measured.

[0075] The insulating cover may include an insulating material, such as plastic. The insulating cover may be fitted to the insulating frame. The insulating cover may cover the integrated circuit, bus bars, sensing plates, sensing bars, and temperature sensors, thereby protecting the electrical components of the first and second integrated circuit assemblies.

[0076] The FFC assembly (127) can provide an electrical connection between the integrated circuit of the first integrated circuit assembly (123) and the integrated circuit of the second integrated circuit assembly (124). Accordingly, measurement values ​​such as temperature and voltage collected from the integrated circuit of the second integrated circuit assembly (124) can be transmitted to the integrated circuit of the first integrated circuit assembly (123) via the FFC assembly (127).

[0077] Referring to FIGS. 3, 6, and 7, refractory structures (128) may be on the unit stacks (US). The refractory structures (128) may cover the unit stacks (US). The refractory structures (128) may be coupled to the unit stacks (US). The refractory structures (128) may be attached to the unit stacks (US). The refractory structures (128) may correspond one-to-one to the unit stacks (US).

[0078] Each of the refractory structures (128) may include a pleated structure. Each of the refractory structures (128) may include first pleats (128W1) and second pleats (128W2). The first pleats (128W1) and the second pleats (128W2) may have a shape complementary to the upper portion of the overlapping battery cells (121), thereby allowing the refractory structures (128) to be easily attached to the unit stacks (US).

[0079] The first and second folds (128W1, 128W2) may have different shapes. The first and second folds (128W1, 128W2) may have shapes that are inverted from each other. The first and second folds (128W1, 128W2) may be symmetrical with respect to the YZ plane. The YZ plane may be substantially parallel to the Y direction and the Z direction, and may be substantially perpendicular to the X direction.

[0080] The first folds (128W1) of the refractory structure (128) can be repeated in the X direction. The number of repetitions of the first folds (128W1) is equal to the number of battery cells (121) included in each of the corresponding banks (BNK). For example, in the example of FIG. 3, since each of the banks (BNK) includes three battery cells (121), the first folds (128W1) can be repeated three times in the X direction.

[0081] The second folds (128W2) of the refractory structure (128) can be repeated in the X direction. The number of repetitions of the second folds (128W2) is equal to the number of battery cells (121) included in each of the corresponding banks (BNK). For example, in the example of FIG. 3, since each of the banks (BNK) includes three battery cells (121), the second folds (128W2) can be repeated three times in the X direction.

[0082] The first pleat (128W1) may include a first slope (128W11) and a second slope (128W12). The length of the first slope (128W11) may be different from the length of the second slope (128W12). The length of the first slope (128W11) may be longer than the length of the second slope (128W12). The second pleat (128W2) may include a third slope (128W21) and a fourth slope (128W22). The length of the third slope (128W21) may be different from the length of the fourth slope (128W22). The length of the third slope (128W21) may be longer than the length of the fourth slope (128W22).

[0083] Each of the first and second slopes (128W11, 128W12) can be oblique to the XY plane. The first slope (128W11) can have a first inclination with respect to the XY plane. The second slope (128W12) can have a second inclination with respect to the XY plane. A magnitude of the first slope can be different from a magnitude of the second slope. A magnitude of the first slope can be smaller than a magnitude of the second slope. The XY plane can be substantially parallel to the X direction and the Y direction, and can be substantially perpendicular to the Z direction.

[0084] Each of the third and fourth slopes (128W21, 128W22) can be oblique to the XY plane. The third slope (128W21) can have a third inclination with respect to the XY plane. The fourth slope (128W22) can have a fourth inclination with respect to the XY plane. A magnitude of the third slope can be different from a magnitude of the fourth slope. A magnitude of the third slope can be smaller than a magnitude of the fourth slope. A magnitude of the third slope can be substantially the same as a magnitude of the first slope. A magnitude of the fourth slope can be substantially the same as a magnitude of the second slope.

[0085] Each of the refractory structures (128) may include a first layer (L1), a second layer (L2), and a third layer (L3). Each of the refractory structures (128) may have a uniform thickness. The second layer (L2) may be on the first layer (L1), and the third layer (L3) may be on the second layer (L2). The second layer (L2) may be interposed between the first and third layers (L1, L3).

[0086] The first layer (L1) may include an adhesive material. The first layer (L1) may include a refractory material. The first layer (L1) may be a refractory adhesive tape. According to exemplary embodiments, the melting temperature and / or ignition point of the first layer (L1) may be about 300°C or higher. According to exemplary embodiments, the melting temperature and / or ignition point of the first layer (L1) may be about 600°C or higher. According to exemplary embodiments, the melting temperature and / or ignition point of the first layer (L1) may be about 1000°C or higher. According to exemplary embodiments, the melting temperature and / or ignition point of the first layer (L1) may be 1500°C or higher.

[0087] According to exemplary embodiments, the thermal conductivity of the first layer (L1) may be about 20 W / mK or less. According to exemplary embodiments, the thermal conductivity of the first layer (L1) may be about 1 W / mK or less. According to exemplary embodiments, the thermal conductivity of the first layer (L1) may be about 0.3 W / mK or less. The thermal conductivity of the first layer (L1) described above may be measured at room temperature (about 25°C).

[0088] The second layer (L2) may include a refractory material. The second layer (L2) may include a refractory sheet (or, refractory film). The second layer (L2) may include any one of PO (propylene oxide), PU (poly urethane), aramid film, NCG (non-combustible glass fiber sheet), and mPPO (modified polyphenylene oxide) containing glass fiber. The second layer (L2) may include a different material from the first layer (L1). The second layer (L2) may be a refractory sheet. That is, the second layer (L2) is the central structure of the refractory structure (128), and the first and third layers (L1, L3) may be applied with the second layer (L2) as the center. For example, a second layer (L2) may be provided, a first layer (L1) may be attached to the second layer (L2), and then a third layer (L3) may be applied to the second layer (L2). As another example, a second layer (L2) may be provided, a third layer (L3) may be applied to the second layer (L2), and then the first layer (L1) may be attached to the second layer (L2).

[0089] According to exemplary embodiments, the melting temperature and / or ignition point of the second layer (L2) may be about 300°C or higher. According to exemplary embodiments, the melting temperature and / or ignition point of the second layer (L2) may be about 600°C or higher. According to exemplary embodiments, the melting temperature and / or ignition point of the second layer (L2) may be about 1000°C or higher. According to exemplary embodiments, the melting temperature and / or ignition point of the second layer (L2) may be about 1500°C or higher.

[0090] According to exemplary embodiments, the thermal conductivity of the second layer (L2) may be about 20 W / mK or less. According to exemplary embodiments, the thermal conductivity of the second layer (L2) may be about 1 W / mK or less. According to exemplary embodiments, the thermal conductivity of the second layer (L2) may be about 0.3 W / mK or less. The thermal conductivity of the second layer (L2) described above may be measured at room temperature (about 25°C).

[0091] The third layer (L3) may include a refractory material. The third layer (L3) may include a different material from the first layer (L1). The third layer (L3) may include a different material from the second layer (L2). The third layer (L3) may include ceramic. The third layer (L3) may be provided by a spray-type coating agent. The third layer (L3) may also be provided by a paint-type coating agent. The third layer (L3) may be provided using a ceramic water-soluble coating agent. The third layer (L3) may be provided by any one of the following methods: spraying, painting, printing, vapor deposition, dipping, spin coating, roller coating, floating coating, curtain coating, sputtering, coextrusion, etc.

[0092] According to exemplary embodiments, the melting temperature and / or ignition point of the third layer (L3) may be about 300°C or higher. According to exemplary embodiments, the melting temperature and / or ignition point of the third layer (L3) may be about 600°C or higher. According to exemplary embodiments, the melting temperature and / or ignition point of the third layer (L3) may be about 1000°C or higher. According to exemplary embodiments, the melting temperature and / or ignition point of the third layer (L3) may be about 1500°C or higher.

[0093] According to exemplary embodiments, the thermal conductivity of the third layer (L3) may be about 20 W / mK or less. According to exemplary embodiments, the thermal conductivity of the third layer (L3) may be about 1 W / mK or less. According to exemplary embodiments, the thermal conductivity of the third layer (L3) may be about 0.3 W / mK or less. The thermal conductivity of the third layer (L3) described above may be measured at room temperature (about 25°C).

[0094] According to exemplary embodiments, the sum of the thicknesses of the first layer (L1), the second layer (L2), and the third layer (L3) may be in a range of about 10 μm to about 200 μm. According to exemplary embodiments, the sum of the thicknesses of the first layer (L1), the second layer (L2), and the third layer (L3) may be greater than or equal to about 20 μm. According to exemplary embodiments, the sum of the thicknesses of the first layer (L1), the second layer (L2), and the third layer (L3) may be greater than or equal to about 30 μm. According to exemplary embodiments, the sum of the thicknesses of the first layer (L1), the second layer (L2), and the third layer (L3) may be greater than or equal to about 40 μm. According to exemplary embodiments, the sum of the thicknesses of the first layer (L1), the second layer (L2), and the third layer (L3) may be less than or equal to about 150 μm. According to exemplary embodiments, the sum of the thicknesses of the first layer (L1), the second layer (L2), and the third layer (L3) may be about 100 μm or less. According to exemplary embodiments, the sum of the thicknesses of the first layer (L1), the second layer (L2), and the third layer (L3) may be about 90 μm or less. According to exemplary embodiments, the sum of the thicknesses of the first layer (L1), the second layer (L2), and the third layer (L3) may be about 80 μm or less. According to exemplary embodiments, the sum of the thicknesses of the first layer (L1), the second layer (L2), and the third layer (L3) may be about 70 μm or less. According to exemplary embodiments, the sum of the thicknesses of the first layer (L1), the second layer (L2), and the third layer (L3) may be about 60 μm or less. According to exemplary embodiments, the sum of the thicknesses of the first layer (L1), the second layer (L2), and the third layer (L3) may be about 50 μm or less.

[0095] According to exemplary embodiments, each of the first layer (L1), the second layer (L2), and the third layer (L3) may have a uniform thickness. According to exemplary embodiments, the first layer (L1), the second layer (L2), and the third layer (L3) may have different thicknesses, but are not limited thereto. The first layer (L1), the second layer (L2), and the third layer (L3) may also have the same thickness.

[0096] According to exemplary embodiments, the thickness of the second layer (L2) may be greater than the thickness of the first layer (L1). According to exemplary embodiments, the thickness of the third layer (L3) may be greater than the thickness of the first layer (L1). According to exemplary embodiments, the thickness of the third layer (L3) may be greater than the thickness of the second layer (L2).

[0097] According to exemplary embodiments, the thickness of the first layer (L1) may be in a range of about 5 μm to about 20 μm. According to exemplary embodiments, the thickness of the first layer (L1) may be about 6 μm or more. According to exemplary embodiments, the thickness of the first layer (L1) may be about 7 μm or more. According to exemplary embodiments, the thickness of the first layer (L1) may be about 8 μm or more. According to exemplary embodiments, the thickness of the first layer (L1) may be about 15 μm or less. According to exemplary embodiments, the thickness of the first layer (L1) may be about 10 μm or less.

[0098] The thickness range of the first layer (L1) described above can prevent the thickness of the first layer (L1) from becoming excessively large while providing sufficient adhesion to the refractory structure (128). Accordingly, a decrease in the energy density of a battery device including a battery cell (121), such as a battery cell assembly (120, see FIG. 7), can be prevented.

[0099] According to exemplary embodiments, the thickness of the second layer (L2) may be in a range of about 10 μm to about 50 μm. According to exemplary embodiments, the thickness of the second layer (L2) may be greater than or equal to about 11 μm. According to exemplary embodiments, the thickness of the second layer (L2) may be greater than or equal to about 12 μm. According to exemplary embodiments, the thickness of the second layer (L2) may be less than or equal to about 45 μm. According to exemplary embodiments, the thickness of the second layer (L2) may be less than or equal to about 40 μm. According to exemplary embodiments, the thickness of the second layer (L2) may be less than or equal to about 35 μm. According to exemplary embodiments, the thickness of the second layer (L2) may be less than or equal to about 30 μm. According to exemplary embodiments, the thickness of the second layer (L2) may be less than or equal to about 25 μm. According to exemplary embodiments, the thickness of the second layer (L2) may be about 20 μm or less. According to exemplary embodiments, the thickness of the second layer (L2) may be about 15 μm or less.

[0100] The thickness range of the second layer (L2) described above can prevent the thickness of the refractory structure (128) from becoming excessively large, and thus, a decrease in the energy density of a battery device including a battery cell (121), such as a battery cell assembly (120, see FIG. 7), can be prevented.

[0101] According to exemplary embodiments, the thickness of the third layer (L3) may be in a range of about 10 μm to about 50 μm. According to exemplary embodiments, the thickness of the third layer (L3) may be about 15 μm or more. According to exemplary embodiments, the thickness of the third layer (L3) may be about 20 μm or more. According to exemplary embodiments, the thickness of the third layer (L3) may be about 25 μm or more. According to exemplary embodiments, the thickness of the third layer (L3) may be about 50 μm or less. According to exemplary embodiments, the thickness of the third layer (L3) may be about 45 μm or less. According to exemplary embodiments, the thickness of the third layer (L3) may be about 35 μm or less. According to exemplary embodiments, the thickness of the third layer (L3) may be about 30 μm or less.

[0102] When the thickness of the third layer (L3) increases, the fire resistance performance of the refractory structure (128) is improved, but since the thickness of the refractory structure (128) increases, the energy density of the battery device including the battery cell (121), such as the battery cell assembly (120, see FIG. 7), is reduced. That is, the thickness of the third layer (L3) can be determined based on the energy density and the fire resistance performance, which are in a trade-off relationship with each other. The thickness range of the third layer (L3) described above can prevent the thickness of the refractory structure (128) from becoming excessively large, while at the same time providing sufficient fire resistance performance to the refractory structure (128).

[0103]

[0104] (Example 2)

[0105] FIG. 8 is a flowchart illustrating a method for manufacturing a secondary battery according to exemplary embodiments.

[0106] FIGS. 9 to 13 are drawings for explaining a method of manufacturing a secondary battery according to exemplary embodiments.

[0107] Referring to FIGS. 8 and 9, a carrier (PC) and a liner (LN) can be combined with a refractory stack (FRS) in P110. The carrier (PC) can have relatively high rigidity and thickness. Accordingly, the refractory stack (FRS) can be easily handled by combining the carrier (PC) and the refractory stack (FRS).

[0108] The refractory stack (FRS) may include the first to third layers (L1, L2, L3) of FIG. 7.

[0109] The carrier (PC) may include, but is not limited to, polyethylene terephthalate (PET). The thickness of the carrier (PC) may be greater than the thickness of the refractory stack (FRS). The thickness of the carrier (PC) may range from about 100 μm to about 200 μm.

[0110] A liner (LN) can cover one side of a refractory stack (FRS). The liner (LN) can prevent contaminants from adhering to the first layer (L1) of the refractory stack (FRS). The liner (LN) can be attached to and detached from the first layer (L1) without damaging the refractory stack (FRS).

[0111] Referring to FIGS. 8 to 10, a refractory stack (FRS) can be formed to provide a refractory structure (128) at P120. A carrier (PC) and a liner (LN) can be formed together with the refractory stack (FRS). By processing P120, the refractory stack (FRS) can be formed into the corrugated structure of FIG. 6, thereby providing the refractory structure (128).

[0112] Next, referring to FIGS. 8, 10, and 11, at P130, the liner (LN) can be separated from the refractory structure (128). The refractory structure (128) can be transported with the liner (LN) attached to a site where the assembly process of the battery cell assembly (120, see FIG. 1) is performed, and the liner (LN) can be removed before being attached to the unit stack (US) as in FIG. 12.

[0113] Next, referring to FIGS. 8 and 12, a refractory structure (128) can be attached to the unit stack (US) at P140. Attaching the refractory structure (128) can include pressurizing the refractory structure (128) and the unit stack (US) with a pressurizing device (SR), such as a soft silicone roller.

[0114] Next, referring to FIGS. 8, 12, and 13, at P150, the carrier (PC) can be separated from the refractory structure (128). According to exemplary embodiments, when the refractory structure (128) is coupled to a unit stack (US) including two or more battery cells, the refractory stack (FRS, see FIG. 9) is pre-formed to have a shape complementary to the upper portion of the unit stack (US), and then the refractory structure (128) having a wrinkled structure is coupled to the unit stack (US), thereby improving the yield and throughput of the assembly process of the battery cell assembly.

[0115]

[0116] (Example 3)

[0117] FIGS. 14 and 15 are cross-sectional views illustrating a refractory structure (128') according to other exemplary embodiments.

[0118] Referring to FIGS. 14 and 15, the unit stack (US') may be different from the unit stack (US) of FIG. 3. More specifically, the unit stack (US') may include three banks (BNK'), and each of the banks (BNK') of the unit stack (US') may include two battery cells (121).

[0119] Accordingly, the refractory structure (128') may include four first pleats (128W1) and two second pleats (128W2) corresponding to changes in the unit stack (US'). The second pleats (128W2) may be interposed between the first pleats (128W1). That is, in the X direction, two first pleats (128W1) may be repeated, two second pleats (128W2) may be repeated, and then two first pleats (128W1) may be repeated again.

[0120] The refractory structure (128') may have different shapes depending on the arrangement of the battery cells (121) covered by the refractory structure (128'). Furthermore, the arrangement of the battery cells (121) may be changed depending on the electrical output target (i.e., target voltage and target current) of the battery cells (121). A person skilled in the art will readily arrive at embodiments in which the unit stack includes any number of banks, and each of the banks includes any number of battery cells, based on the description herein.

[0121]

[0122] (Example 4)

[0123] FIG. 16 is a plan view showing a battery pack (100) according to exemplary embodiments.

[0124] Referring to FIGS. 1 to 3 and 16, a battery pack (100) may include a pack housing (110), a plurality of battery cell assemblies (120), and cross beams (131). The battery pack (100) may be a final product mounted in an application such as a vehicle.

[0125] The pack housing (110) can provide a space for mounting battery cell assemblies (120). The pack housing (110) can include a base plate (111), side walls (112, 113, 114, 115), and a center beam (116).

[0126] Here, two directions substantially parallel to the mounting surface 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 mounting 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.

[0127] The base plate (111) and the side walls (112, 113) may each be provided by an extrusion process. The extrusion direction of each 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. The side walls (112, 113, 114, 115) may be substantially perpendicular to the base plate (111).

[0128] 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 unit plates joined by friction stir welding.

[0129] The center beam (116) may extend in the X direction. The center beam (116) may be interposed between the side walls (112, 113). The center beam (116) may be included in a center plate, which is one of a plurality of unit plates that are friction stir welded to each other. Accordingly, the center beam (116) may be formed together with the center plate, and the center beam (116) may be a continuous element integrally formed with the center plate.

[0130] The base plate (111) may include a plurality of cooling channels. The plurality of cooling channels may provide passages for the movement of a coolant, such as water, for example. The plurality of cooling channels may be formed by an extrusion process. The plurality of cooling channels may extend in the X direction. The plurality of cooling channels may be spaced apart in the Y direction.

[0131] 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).

[0132] The center beam (116) and cross beams (131) can isolate the plurality of battery cell assemblies (120) from each other. The plurality of battery cell assemblies (120) can be spaced apart in the Y direction with the center beam (116) therebetween. The center beam (116) can be interposed between the plurality of battery cell assemblies (120). The plurality of battery cell assemblies (120) can be spaced apart in the X direction with the cross beams (131) therebetween. The cross beams (131) can be interposed between the plurality of battery cell assemblies (120).

[0133] The arrangement of the plurality of battery cell assemblies (120) in FIG. 16 can be referred to as a 3 * 2 arrangement. The arrangement of the plurality of battery cell assemblies (120) disclosed in FIG. 16 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 M ​​* N (wherein, M and N are each integers greater than or equal to 2) based on the description herein.

[0134] The battery pack (100) may further include leads coupled to side walls (112, 113, 114, 115) of the pack housing (110). The leads may cover elements mounted inside the battery pack (100), such as a plurality of battery cell assemblies (120) and electrical components. The leads may be secured to the pack housing (110) by mechanical coupling means, such as bolting.

[0135] The battery pack may further include exhaust devices coupled to the sidewalls (114, 115). Either of the sidewalls (114, 115) may include exhaust holes connected to the exhaust devices. The exhaust devices may be configured to delay thermal propagation by releasing high-temperature gas within the battery pack (100) to the outside when a thermal runway event occurs in the plurality of battery cell assemblies (120).

[0136] 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.

[0137] According to exemplary embodiments, for each of the plurality of battery cells (121) of each of the plurality of battery cell assemblies (120), a refractory structure (128) may be spaced apart from the base plate (111) with a cell case (121C) therebetween. According to exemplary embodiments, the refractory structure (128) may be at a higher level than the cell case (121C) with respect to the base plate (111). That is, the refractory structure (128) may cover an upper portion of the cell case (121C). Accordingly, even in a thermal runaway event, when high-temperature gas and flame are discharged through an exhaust path between the lead and the plurality of battery cell assemblies (120), the battery cell (121) may be protected by the refractory structure (128), and the safety of the battery pack (100) may be enhanced.

[0138] 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.

[0139] 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).

[0140] 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. Additional electrical components may be interposed between the plurality of battery cell assemblies (120) and the sidewall (115). The space between the battery cell assemblies (120) and the sidewall (115) may also be referred to as an electrical component mounting area.

[0141] The battery pack (100) may further include a plurality of inter-busbars 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 inter-busbars. Accordingly, the battery pack (100) may be configured to output a high voltage to an external load (e.g., a vehicle motor).

[0142]

[0143] 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. A plurality of battery cells arranged in a first direction; and Including a refractory structure arranged on the plurality of battery cells, A battery cell assembly characterized in that the refractory structure is in contact with each of the plurality of battery cells and has a wrinkled structure.

2. In paragraph 1, The above wrinkled structure includes first wrinkles and second wrinkles arranged along the first direction, and A battery cell assembly characterized in that the shapes of the first and second wrinkles are different.

3. In paragraph 2, The first wrinkle includes a first slope oblique to the first direction and a second slope oblique to the first direction, and A battery cell assembly, characterized in that the second fold includes a third slope oblique to the first direction and a fourth slope oblique to the first direction.

4. In paragraph 3, A battery cell assembly, characterized in that the size of the first slope of the first slope is different from the size of the second slope of the second slope.

5. In paragraph 4, A battery cell assembly, characterized in that the size of the first slope is smaller than the size of the second slope.

6. In paragraph 3, A battery cell assembly, characterized in that the size of the third slope of the third slope is different from the size of the fourth slope of the fourth slope.

7. In paragraph 6, A battery cell assembly, characterized in that the size of the third slope is smaller than the size of the fourth slope.

8. In paragraph 6, A battery cell assembly, characterized in that the size of the third slope is the same as the size of the first slope of the first slope.

9. In paragraph 6, A battery cell assembly, characterized in that the size of the fourth slope is the same as the size of the second slope of the second slope.

10. In paragraph 1, A battery cell assembly characterized in that the above refractory structure comprises multiple layers.

11. In paragraph 1, The above refractory structure comprises first to third layers, and A battery cell assembly, characterized in that the first layer comprises a refractory adhesive tape, the second layer comprises a refractory sheet, and the third layer comprises a refractory coating.

12. In paragraph 11, The second layer may include one of PO (propylene oxide), PU (poly urethane), aramid film, NCG (non-combustible glass fiber sheet), and mPPO (modified polyphenylene oxide) containing glass fiber.

13. In paragraph 11, A battery cell assembly characterized in that the third layer comprises ceramic.

14. In paragraph 11, A battery cell assembly, characterized in that the thickness of the third layer is greater than the thickness of the first layer.

15. In paragraph 11, A battery cell assembly, characterized in that the thickness of the third layer is greater than the thickness of the second layer.

16. In paragraph 11, The thickness of the third layer is 25 μm or more, and A battery cell assembly, characterized in that the thickness of the third layer is 30 μm or less.

17. In paragraph 11, The sum of the thicknesses of the first to third layers is 40 μm or more, and A battery cell assembly, characterized in that the sum of the thicknesses of each of the first to third layers is 50 μm or less.

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