Battery pack and energy storage device including same

Abstract

A battery pack according to the present invention includes at least one cell assembly and a pack case that houses the at least one cell assembly, wherein the cell assembly includes: two or more cell stacks having stacked battery cells; cell pressing units that are arranged at the outermost edges on both sides of each of the cell stacks along the stacking direction of the battery cells so as to individually apply pressing forces to each of the cell stacks; and bus bar frame assemblies that are arranged at the front and rear of the cell stacks in a direction intersecting the stacking direction of the battery cells, electrically connect the battery cells, and integrally support the two or more cell stacks and the cell pressing units.

Description

[Technical Field]

[0001] The present invention relates to a battery pack, and more particularly to a battery pack for suppressing heat transfer between battery cells, minimizing performance degradation due to cell swelling, fire safety, and battery pack deformation.

[0002] This application claims priority based on Korean Patent Application No. 10-2022-0181731 filed on December 22, 2022 and Korean Patent Application No. 10-2023-0142184 filed on October 23, 2023, and the contents disclosed in the specifications and drawings of those applications are incorporated herein in their entirety. [Background technology]

[0003] Currently, commercially available batteries include nickel-cadmium batteries, nickel-metal hydride batteries, nickel-zinc batteries, and lithium batteries. Among these, lithium batteries are attracting attention due to their advantages of being able to be freely charged and discharged since they have almost no memory effect compared to nickel-based batteries, as well as their extremely low self-discharge rate and high energy density.

[0004] Such lithium secondary batteries primarily use lithium-based oxides and carbon materials as the positive and negative electrode active materials, respectively, and include an electrode assembly in which a separator is sandwiched between positive and negative electrode plates coated with the positive and negative electrode active materials, and an exterior material, such as a battery case, that encloses the electrode assembly together with an electrolyte.

[0005] In recent years, secondary batteries have been widely used not only in small devices such as portable electronic devices but also in medium-sized and large devices such as automobiles and power storage devices. When used in such medium-sized and large devices, multiple secondary batteries are electrically connected to increase capacity and output. In particular, pouch-type secondary batteries are often used in such medium-sized and large devices because of their advantage of being easily stacked.

[0006] Meanwhile, in recent years, there has been an increasing need for large-capacity structures, including use as an energy storage source, and there has been an increasing demand for battery packs that include multiple secondary batteries electrically connected in series and / or parallel, as well as battery modules that house these secondary batteries and battery management systems (BMS).

[0007] In addition, such battery packs generally have a metal outer housing to protect the multiple secondary batteries from external impacts and to house and store them. Meanwhile, demand for high-capacity battery packs has been increasing in recent years.

[0008] However, high-capacity battery packs have the problem that if one of the multiple secondary batteries built into them catches fire or explodes, the heat and flames will be transmitted to adjacent secondary batteries, increasing the risk of a chain reaction of fires or explosions.

[0009] Furthermore, in the case of pouch-type secondary batteries, repeated charge / discharge cycles can cause the electrodes to thicken, or side reactions can decompose the internal electrolyte, generating gas and causing the secondary battery to expand, a phenomenon known as "swelling." Conventionally, to suppress or mitigate the swelling, two end plates are placed on both outermost sides of stacked pouch-type secondary batteries to compress the batteries. However, as the number of stacked pouch-type secondary batteries increases, it becomes difficult to uniformly and stably compress all of the pouch-type secondary batteries. If the swelling worsens, the performance of the secondary batteries may deteriorate, and the appearance of the battery pack may change, adversely affecting the structural stability of the battery pack.

[0010] Therefore, a high-capacity battery pack including a plurality of secondary batteries is required to have a design structure that minimizes the above-mentioned problems. Summary of the Invention [Problem to be solved by the invention]

[0011] The present invention has been made to solve the above problems, and an object of the present invention is to provide a battery pack that can suppress heat transfer between battery cells, performance degradation due to cell swelling, and deformation of the battery pack.

[0012] The technical problems that the present invention aims to solve are not limited to the above-mentioned problems, and other problems not mentioned will be clearly understood by those skilled in the art from the description of the invention given below. [Means for solving the problem]

[0013] A battery pack according to the present invention includes at least one cell assembly and a pack case that houses the at least one cell assembly, wherein the cell assembly may include: two or more cell stacks having stacked battery cells; cell pressing units that are arranged at the outermost edges on both sides of each of the cell stacks along the stacking direction of the battery cells so as to individually apply pressing forces to each of the cell stacks; and bus bar frame assemblies that are arranged at the front and rear of the cell stacks in a direction intersecting the stacking direction of the battery cells, electrically connect the battery cells, and integrally support the two or more cell stacks and the cell pressing units.

[0014] The battery cell is a pouch-type battery cell, and the cell stack includes a first cell stack and a second cell stack arranged alongside the first cell stack at a predetermined interval, and an air layer may be provided between the first cell stack and the second cell stack.

[0015] The cell pressing unit may include a first left pressing unit facing the battery cell at the outermost left side of the first cell stack, a first right pressing unit facing the battery cell at the outermost right side of the first cell stack, a second left pressing unit facing the battery cell at the outermost left side of the second cell stack, and a second right pressing unit facing the battery cell at the outermost right side of the second cell stack.

[0016] The first left-side pressing unit, the first right-side pressing unit, the second left-side pressing unit, and the second right-side pressing unit may each include a rigid plate made of a metal material or a reinforced plastic material having high mechanical rigidity.

[0017] The first left-side pressing unit, the first right-side pressing unit, the second left-side pressing unit, and the second right-side pressing unit may each include an insulating sheet attached to a surface of the rigid plate, and a compressible pad having one surface in contact with the insulating sheet and the other surface in contact with the battery cell.

[0018] The first right-side pressing unit and the second left-side pressing unit may be arranged at a predetermined distance from each other, and an air layer may be provided between the first right-side pressing unit and the second left-side pressing unit.

[0019] The bus bar frame assembly may include a central insertion portion into which an end portion of the first right pressing unit and an end portion of the second left pressing unit are inserted, and the central insertion portion may include a gap maintaining protrusion that protrudes into a space between the end portion of the first right pressing unit and the end portion of the second left pressing unit.

[0020] The cell pressing unit may further include a first strap member having one end fixedly connected to the first left pressing unit and the other end fixedly connected to the first right pressing unit, the first strap member extending across the width of the first cell stack and wrapping around at least one of the upper and lower portions of the periphery of the first cell stack, and a second strap member having one end fixedly connected to the second left pressing unit and the other end fixedly connected to the second right pressing unit, the second strap member extending across the width of the second cell stack and wrapping around at least one of the upper and lower portions of the periphery of the second cell stack.

[0021] The bus bar frame assembly may include a bus bar frame made of an electrically insulating material and sized to cover the front or rear surfaces of the first cell stack and the second cell stack, and a plurality of bus bars made of a metal material, attached to the bus bar frame, and connected to electrode leads of the battery cells.

[0022] The at least one cell assembly may be a plurality of cell assemblies arranged side by side, and the pack case may include a base plate that supports the plurality of cell assemblies below the plurality of cell assemblies, and a pack cover that covers the plurality of cell assemblies and interconnects with the base plate.

[0023] The base plate includes support frame portions provided on an edge region extending in the arrangement direction of the cell assemblies, protruding upward at predetermined intervals along the arrangement direction of the cell assemblies, and configured to support the bus bar frame assembly of each cell assembly, and recesses provided between adjacent support frames, and the bus bar frame assembly of each cell assembly may include a mounting plate arranged on the upper surface of the support frame portion, and a mounting guide block protruding downward from the mounting plate so as to be insertable into the corresponding recess.

[0024] The cell assembly is configured such that when each of the mounting guide blocks is inserted into the corresponding recess and placed on the base plate, each of the mounting guide blocks and the support frame portion forms a continuous assembly wall along the arrangement direction of the cell assembly, and the assembly wall has a rod insertion portion whose outer surface has a shape that is concave inward, and a rod member having a length corresponding to the length of the assembly wall can be configured to be inserted into the rod insertion portion.

[0025] The battery cell may be a pouch-type battery cell, and the pouch-type battery cell may include a pouch exterior material that houses an electrode assembly and has a lower edge portion, a front edge portion, and a rear edge portion heat-sealed, and the cell stack may be disposed such that the lower edge portion of the pouch exterior material faces the base plate, and the base plate may include support ribs that protrude in a lattice shape from a bottom surface and support the cell stack so as to space it from the bottom surface, and at least one vent hole that penetrates the bottom surface.

[0026] The cell stacks may be arranged at predetermined intervals along the stacking direction of the battery cells, with an air layer between each of the cell stacks, the pack cover may have an upper vent hole formed therethrough, the base plate may have a lower vent hole formed therethrough, and the upper vent hole, the air layer, and the lower vent hole may all be configured to match in the vertical direction.

[0027] According to another aspect of the present invention, there may be provided an energy storage device including the battery pack described above. [Effects of the Invention]

[0028] According to the present invention, it is possible to provide a battery pack capable of suppressing heat transfer between battery cells, performance degradation due to cell swelling, and deformation of the battery pack.

[0029] In particular, according to the present invention, by distributing the pressing structure for the battery cells in the cell assembly unit, it is possible to more effectively prevent the swelling phenomenon of the battery cells and also to limit the heat transfer between the battery cells.

[0030] In addition, the present invention may have various other technical effects, which are described in the sections for each implementation configuration, and descriptions of technical effects that can be easily inferred by those skilled in the art will be omitted. [Brief explanation of the drawings]

[0031] [Figure 1] 1 is a perspective view showing a battery pack according to an embodiment of the present invention; [Figure 2] FIG. 2 is a view of the battery pack of FIG. 1 with the pack cover removed. [Figure 3] FIG. 1 is a perspective view of a cell assembly according to one embodiment of the present invention. [Figure 4] FIG. 4 is an exploded perspective view of the cell assembly of FIG. 3. [Figure 5] FIG. 4 is a cutaway perspective view of the cell assembly taken along line AA' in FIG. 3. [Figure 6] FIG. 6 is a schematic cross-sectional view of FIG. 5. [Figure 7] FIG. 7 is a partially enlarged view of FIG. [Figure 8] FIG. 2 is a side view of a cell assembly according to one embodiment of the present invention. [Figure 9] FIG. 2 is a perspective view showing a base plate and a rod member according to an embodiment of the present invention. [Figure 10] FIG. 10 is a partially enlarged view of FIG. [Figure 11] 1A to 1C are diagrams showing an assembly process or assembly structure of a base plate and a plurality of cell assemblies according to one embodiment of the present invention. [Figure 12] 1A to 1C are diagrams showing an assembly process or assembly structure of a base plate and a plurality of cell assemblies according to one embodiment of the present invention. [Figure 13]1A to 1C are diagrams showing an assembly process or assembly structure of a base plate and a plurality of cell assemblies according to one embodiment of the present invention. [Figure 14] 1 is a cutaway perspective view of a battery pack according to an embodiment of the present invention; [Figure 15] FIG. 15 is a partially enlarged view of FIG. [Figure 16] 1 is a cross-sectional view of a portion of a battery pack according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0032] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, the terms and words used in this specification and claims should not be construed as being limited to their ordinary or dictionary meanings, but should be construed as having meanings and concepts corresponding to the technical ideas of the present invention, based on the principle that the inventor himself can appropriately define the concepts of terms in order to best describe the invention. Therefore, it should be understood that the embodiment described in this specification and the configuration shown in the drawings are merely the most preferred embodiment of the present invention and do not represent the entire technical ideas of the present invention, and therefore, various equivalents and modifications that can be substituted therefor may exist at the time of filing this application.

[0033] In the drawings, the size of each component or specific parts of the component may be slightly exaggerated, omitted, or illustrated schematically for ease of explanation and clarity. Therefore, the size of each component does not fully reflect the actual size. If it is recognized that a detailed description of known technologies related to the present invention may obscure the gist of the present invention, the detailed description will be omitted.

[0034] Throughout this specification, when a part is said to "comprise" a certain component, this does not mean that it may further include other components, unless otherwise specified.

[0035] FIG. 1 is a perspective view showing a battery pack according to one embodiment of the present invention, FIG. 2 is a view of the battery pack of FIG. 1 with a pack cover removed, FIG. 3 is a perspective view showing a cell assembly according to one embodiment of the present invention, and FIG. 4 is an exploded perspective view of the cell assembly of FIG. 3.

[0036] A battery pack 10 according to the present invention includes at least one cell assembly 100 and a pack case 400 that houses the at least one cell assembly 100 .

[0037] As shown in Figures 1 and 2, the battery pack 10 according to this embodiment may include a pack case 400 including a pack cover 410 and a base plate 420, and a plurality of cell assemblies 100A, 100B, 100C, and 100D arranged along one direction (Y direction) on the base plate 420.

[0038] Each of the cell assemblies 100 may include two or more cell stacks 110 , 120 comprising stacked battery cells 101 , a cell pressing unit 200 , and a busbar frame assembly 300 .

[0039] One cell assembly 100 may be configured to include two cell stacks, or three or four cell stacks, where the cell stack refers to an assembly of battery cells 101 in which a predetermined number of approximately plate-shaped battery cells 101 are stacked.

[0040] The cell stacks 110 and 120 may be formed of pouch-type battery cells 101. As an alternative to the pouch-type battery cells 101, prismatic battery cells 101 in which an electrode assembly is housed in a rectangular parallelepiped metal can may also be used.

[0041] 3 and 4, the cell assembly 100 according to this embodiment includes two cell stacks identified as a first cell stack 110 and a second cell stack 120. The first and second cell stacks 110 and 120 are assemblies of pouch-type battery cells 101 stacked in one direction (Y direction). The first and second cell stacks 120 may be provided in a form in which the pouch-type battery cells 101 are stacked horizontally with their wide surfaces standing vertically relative to the ground.

[0042] The pouch-type battery cell 101 may be manufactured by housing an electrode assembly and an electrolyte material inside a pouch exterior material made of a laminate film containing a soft metal and then sealing the pouch exterior material. Here, the electrode assembly includes a positive electrode plate, a negative electrode plate, and a separator (separation membrane) interposed between the positive electrode plate and the negative electrode plate. The pouch-type battery cell 101 may include an electrode lead 102 functioning as an electrode terminal, and the electrode lead 102 may be electrically connected to the electrode assembly and configured to be exposed to the outside of the pouch exterior material. The electrode lead 102 may include a pair of positive and negative electrode leads. The positive and negative electrode leads may be provided at a front and a rear portion, respectively, along the longitudinal direction (X direction) of the pouch-type battery cell 101.

[0043] In this embodiment, one cell assembly 100 includes a total of 16 pouch-type battery cells 101, and the first cell stack 110 and the second cell stack 120 each include eight pouch-type battery cells 101. Meanwhile, the number of pouch-type battery cells 101 included in the cell assembly 100 can be increased or decreased depending on the desired energy capacity or output.

[0044] The first cell stack 110 and the second cell stack 120 are arranged side by side with a predetermined gap therebetween. For example, as shown in Figures 3 and 5, the first cell stack 110 and the second cell stack 120 are spaced apart by a predetermined gap. Therefore, the cell assembly 100 according to this embodiment has an air layer K1 between the first cell stack 110 and the second cell stack 120.

[0045] The air layer K1 may serve to block heat transfer between the first cell stack 110 and the second cell stack 120. For example, when a thermal runaway event occurs in one of the battery cells 101 of the second cell stack 120, the air layer K1 may prevent heat from transferring from the second cell stack 120 to the first cell stack 110. Therefore, when a thermal event occurs in a specific battery cell 101, the cascading propagation of heat to all battery cells 101 included in the cell assembly 100 may be blocked.

[0046] Furthermore, the air layer K1 can be used as a gas transfer path when gas is generated in the battery cell 101. If a large amount of gas generated in the battery cell 101 is not discharged to the outside in the event of an internal fire, the internal pressure of the battery pack may rise rapidly, resulting in structural collapse or explosion. Therefore, in the battery pack 10 according to the present invention, the air layer K1 between the first cell stack 110 and the second cell stack 120 is used as a gas transfer path, and as described below, an upper vent hole 411 and a lower vent hole 425 provided in the pack case 400 are vertically connected to the air layer K1, allowing vent gas to be smoothly discharged to the outside of the battery pack. Therefore, the battery pack according to the present invention has an extremely low risk of structural collapse or explosion due to an increase in internal pressure, even in the event of an internal fire.

[0047] The cell pressing units 200 may be disposed on the outermost sides of each of the cell stacks and configured to apply a pressing force to each of the cell stacks. Here, the outermost sides of each of the cell stacks refer to the outer side of the first battery cell 101 and the outer side of the last battery cell 101 in the stacking direction of the battery cells 101.

[0048] Specifically, referring to Figures 3 and 4, the cell pressing unit 200 according to this embodiment may include first cell pressing units 210, 220 for pressing the first cell stack 110, and second cell pressing units 240, 250 for pressing the second cell stack 120.

[0049] The first cell pressing units 210 and 220 may include a first left pressing unit 210 and a first right pressing unit 220 , and the second cell pressing units 240 and 250 may include a second left pressing unit 240 and a second right pressing unit 250 .

[0050] The first left pressing unit 210 may be positioned facing the battery cell 101 at the outermost left side of the first cell stack 110, the first right pressing unit 220 may be positioned facing the battery cell 101 at the outermost right side of the first cell stack 110, the second left pressing unit 240 may be positioned facing the battery cell 101 at the outermost left side of the second cell stack 120, and the second right pressing unit 250 may be positioned facing the battery cell 101 at the outermost right side of the second cell stack 120.

[0051] The first left pressing unit 210, the first right pressing unit 220, the second left pressing unit 240 and the second right pressing unit 250 can each be made from a rigid plate 201 made of a metal material or a reinforced plastic material with high mechanical rigidity.

[0052] The first cell stack 110 is pressed by the first left-side pressing unit 210 and the first right-side pressing unit 220, and the second cell stack 120 can be pressed by the second left-side pressing unit 240 and the second right-side pressing unit 250 at a position spaced a predetermined distance from the first cell stack 110.

[0053] For example, when assembling the cell assembly 100, the first cell stack 110 may be pressed by the first left pressing unit 210 and the first right pressing unit 220, and the first cell stack 110, the first left pressing unit 210, and the first right pressing unit 220 may be integrally assembled into a bus bar frame assembly 300, which will be described later. The bus bar frame assembly 300 may be configured so that both ends of the first left pressing unit 210 and both ends of the first right pressing unit 220 can be inserted and fixed, respectively. By combining the first left pressing unit 210 and the first right pressing unit 220 with the bus bar frame assembly 300, the pressing force on the first cell stack 110 can be maintained.

[0054] In addition, the second cell stack 120 is pressed by the second left pressing unit 240 and the second right pressing unit 250, and the second cell stack 120, the second left pressing unit 240, and the second right pressing unit 250 can be integrally assembled to the bus bar frame assembly 300. The bus bar frame assembly 300 may be configured so that both ends of the second left pressing unit 240 and both ends of the second right pressing unit 250 can be inserted and fixed. By combining the second left pressing unit 240 and the second right pressing unit 250 with the bus bar frame assembly 300, the pressing force on the second cell stack 120 can be maintained.

[0055] Furthermore, as shown in FIG. 5, by assembling the first right pressing unit 220 and the second left pressing unit 240 to the bus bar frame assembly 300 so that they are arranged at a predetermined distance from each other, an air layer K1 can be provided between the first right pressing unit 220 and the second left pressing unit 240.

[0056] The cell pressing unit 200 may be configured with a plate-shaped rigid plate 201. However, if the rigid plate 201 is made of metal, ensuring electrical insulation from the battery cell 101 becomes an issue, and the surface of the battery cell 101 may be damaged due to a difference in surface roughness between the surface of the battery cell 101 and the rigid plate 201.

[0057] Therefore, the cell pressing unit 200 according to this embodiment may further include an insulating sheet 202 and a compressible pad 203, as shown in FIG.

[0058] The insulating sheet 202 may be attached to the surface of each rigid plate 201. The insulating sheet 202 may be a thin sheet made of a material having insulating, fire-resistant, and heat-insulating properties. For example, the insulating sheet 202 may be made of silicon or mica.

[0059] The compressible pad 203 may be disposed between the insulating sheet 202 and the cell stack. One side of the compressible pad 203 may be configured to contact the insulating sheet 202, and the other side of the compressible pad 203 may be configured to face and contact the outermost battery cells 101 of the cell stack. By using the compressible pad 203 in this manner, the surface pressure of the rigid plate 201 can be applied uniformly to the battery cells 101 without damaging the surfaces of the battery cells 101.

[0060] Meanwhile, the cell pressing unit 200 may further include a strap as a means for strengthening the pressing force on the cell stack.

[0061] The strap according to this embodiment may include a first strap member 230 and a second strap member 260, as shown in FIGS.

[0062] The first strap member 230 may be configured to have one end fixedly connected to the first left-side pressing unit 210 and the other end fixedly connected to the first right-side pressing unit 220, extend across the width of the first cell stack 110, and wrap around at least one of the upper and lower parts of the periphery of the first cell stack 110.

[0063] In this embodiment, the first strap member 230 may include a first upper strap member 230a that wraps around the upper portion of the first cell stack 110, and a first lower strap member 230b that wraps around the lower portion of the first cell stack 110. As a variation of this embodiment, the first strap member 230 may be configured to wrap around the entire periphery of the first cell stack 110.

[0064] The second strap member 260 may be configured to have one end fixedly connected to the second left-side pressing unit 240 and the other end fixedly connected to the second right-side pressing unit 250, extend across the width of the second cell stack 120, and wrap around at least one of the upper and lower parts of the periphery of the second cell stack 120.

[0065] In this embodiment, the second strap member 260 may include a second upper strap member 260a that wraps around the upper portion of the second cell stack 120, and a second lower strap member 260b that wraps around the lower portion of the second cell stack 120, substantially similar to the first strap member 230.

[0066] The first strap member 230 and the second strap member 260 may be configured substantially identically. Therefore, hereinafter, a description of the first strap member 230 will be substituted for a description of the second strap member 260.

[0067] The first cell stack 110 may be strapped at its upper and lower peripheries by the first strap members 230 while being pressed by the first left pressing unit 210 and the first right pressing unit 220. The first strap members 230 may be made of a metal material having excellent mechanical rigidity. An insulating film for electrically insulating the first cell stack 110 from the battery cells 101 may be attached to a surface of the first strap member 230 that wraps around the first cell stack 110.

[0068] 4, strap fastening holes H1 may be formed at the upper and lower ends of the rigid plate 201. Both ends of the first strap member 230 may be configured to be fitted into the strap fastening holes H1.

[0069] For example, the first upper strap member 230a may have both ends folded twice in a generally U-shape. One end of the first upper strap member 230a may be fitted into a strap fastening hole H1 provided at the upper end of the first left pressing unit 210, as shown in FIG. 5. The other end of the first upper strap member 230a may be fitted into a strap fastening hole (not shown) provided at the upper end of the first right pressing unit 220.

[0070] The first lower strap member 230b has the same shape as the first upper strap member 230a, and like the first upper strap member 230a, can be fitted into a strap fastening hole H1 provided at the lower end of the first left pressing unit 210 and a strap fastening hole (not shown) provided at the lower end of the first right pressing unit 220.

[0071] The first strap members 230 can be applied at predetermined intervals along the longitudinal direction of the first cell stack 110. Preferably, the first strap members 230 can be applied to a central portion of the first cell stack 110 along the longitudinal direction of the first cell stack 110 and to positions spaced apart at regular intervals on the left and right sides of the central portion.

[0072] Meanwhile, in this embodiment, three first strap members 230 are applied to the upper and lower ends of the first cell stack 110 along the longitudinal direction of the first cell stack 110, but unlike this embodiment, two or four or more first strap members 230 may also be applied to the first cell stack 110.

[0073] In this way, by binding the first cell stack 110 and the first cell pressing units 210, 220 together using the first strap member 230, the pressed state of the first cell stack 110 can be more stably maintained. In addition, by binding the second cell stack 120 and the second cell pressing units 240, 250 together using the second strap member 260, the pressed state of the second cell stack 120 can be more stably maintained.

[0074] The bus bar frame assemblies 300 are disposed in front of and behind the first and second cell stacks 110 and 120, which are arranged in parallel with each other at a predetermined interval in the left-right direction (Y direction). In other words, the bus bar frame assemblies 300 are disposed in front of and behind the cell stacks in a direction intersecting the stacking direction of the battery cells 101.

[0075] The bus bar frame assembly 300 may be configured to integrally support the cell stack and the cell pressing unit 200 and to electrically connect the battery cells 101 .

[0076] The bus bar frame assembly 300 may be provided to correspond to the number of cell stacks. That is, although the bus bar frame assembly 300 of the present embodiment is designed to accommodate two cell stacks, if the number of cell stacks is three, for example, the bus bar frame assembly 300 may also be configured to support and electrically connect the three cell stacks.

[0077] The bus bar frame assembly 300 includes a bus bar frame 310 and a plurality of bus bars 320 .

[0078] The bus bar frame 310 may be made of an electrically insulating material and may be sized to integrally cover the front or rear surfaces of the first cell stack 110 and the second cell stack 120. Each bus bar frame 310 may have lead slits for passing a predetermined number of electrode leads 102 in the front-rear direction (±X direction). The lead slits may be provided at predetermined intervals along the stacking direction of the battery cells 101.

[0079] The plurality of bus bars 320 may be formed in a rod or plate shape and made of an electrically conductive metal material such as copper, aluminum, nickel, etc. The plurality of bus bars 320 may be attached to the bus bar frame 310 at regular intervals in the stacking direction of the battery cells 101.

[0080] The electrode leads 102 of the pouch-type battery cells 101 constituting the first cell stack 110 and the second cell stack 120 may be drawn out to the outside of the bus bar frame 310 through the corresponding lead slits. That is, as shown in FIG. 3 , the electrode leads 102 drawn out to the outside of the bus bar frame 310 may be bent and fixedly attached to the surface of the corresponding bus bar 320. For example, the bus bar 320 and the electrode leads 102 may be fixedly coupled to each other by laser welding or ultrasonic welding. For example, the positive electrode leads of two battery cells 101 may be overlapped and attached to a specific bus bar 320, and the negative electrode leads of the other two battery cells 101 may be overlapped and attached to the specific bus bar 320. In this way, four battery cells 101 may be connected in series and / or in parallel. In this way, by attaching the electrode leads 102 of the battery cells 101 to the corresponding bus bars, all of the battery cells 101 included in the first cell stack 110 and the second cell stack 120 can be connected in series and / or parallel.

[0081] For reference, in this embodiment, one cell assembly 100 includes a total of 16 battery cells 101. The total of 16 battery cells 101 are connected in parallel in groups of four via the bus bar 320, and groups of four battery cells 101 connected in parallel are connected in series. Therefore, in one cell assembly 100 according to this embodiment, the 16 battery cells are electrically connected in a 4-in-4-parallel (4S4P: a combination of four series connections and four parallel connections) configuration.

[0082] In addition, the cell assembly 100 according to the present embodiment has a structure in which the 16 battery cells 101 are divided into two groups of eight battery cells 101 and compressed. That is, as described above, the cell assembly 100 has a structure in which the first cell stack 110 and the second cell stack 120 are compressed independently.

[0083] 6 and 7, the bus bar frame assembly 300 according to an embodiment of the present invention may include a central insertion portion 311 into which the end portions of the first right pressing unit 220 and the second left pressing unit 240 are inserted.

[0084] The central insertion portion 311 may include a gap maintaining protrusion 312 protruding into a space between an end portion of the first right pressing unit 220 and an end portion of the second left pressing unit 240 .

[0085] With respect to the spacing maintaining protrusion 312, the first cell stack 110 may be positioned on the left side of the spacing maintaining protrusion 312 while being pressed by the first cell pressing units 210 and 220 as indicated by "P1," and the second cell stack 120 may be positioned on the right side of the spacing maintaining protrusion 312 while being pressed by the second cell pressing units 240 and 250 as indicated by "P2." The spacing maintaining protrusion 312 may serve to guide the relative positions of components when assembling the bus bar frame 310 to the first cell stack 110 and the second cell stack 120.

[0086] In addition, the gap maintaining protrusion 312 prevents the end portion of the first right-side pressing unit 220 and the end portion of the second left-side pressing unit 240 from abutting against each other, thereby preventing the air layer K1 between the first cell stack 110 and the second cell stack 120 from being blocked.

[0087] 4, the bus bar frame assembly 300 may include hooks 313a and 313b on both sides of the bus bar frame 310. The hooks 313a and 313b may include an upper hook 313a and a lower hook 313b. The first left pressing unit 210 and the second right pressing unit 250 may each include a hook fastening hole H2. The hook fastening hole H2 may include an upper fastening hole and a lower fastening hole.

[0088] 5, upper and lower hooks 313a and 313b provided on the left side of the bus bar frame 310 may be engaged with upper and lower fastening holes of the first left pressing unit 210, respectively. Also, upper and lower hooks 313a and 313b provided on the right side of the bus bar frame 310 may be engaged with upper and lower fastening holes of the second right pressing unit 250, respectively.

[0089] Furthermore, referring primarily to Figures 3, 4 and 8, the bus bar frame assembly 300 according to this embodiment may further include a mounting plate 314 placed on the upper surface of the support frame portion 422 of the base plate 420, which will be described later, and a mounting guide block 315 protruding downward from the mounting plate 314.

[0090] The mounting plate 314 and the mounting guide block 315 are components for improving the ease of assembly and fixation between the plurality of cell assemblies 100 and the base plate 420. The mounting plate 314 and the mounting guide block 315 will be described below in conjunction with the base plate 420.

[0091] A battery pack 10 according to the present invention includes one or more of the above-described cell assemblies 100. For example, as shown in the embodiment of Fig. 2, the battery pack 10 may include four cell assemblies 100 arranged side by side. The battery pack 10 may also include a pack case 400 for protecting the four cell assemblies 100 from the outside.

[0092] The pack case 400 may include a base plate 420 that supports the four cell assemblies 100 below the four cell assemblies 100, and a pack cover 410 that covers the four cell assemblies 100 and is interconnected with the base plate 420.

[0093] The pack cover 410 may be formed in the shape of a rectangular parallelepiped box with an open bottom, and the base plate 420 may be formed in the shape of a substantially plate having an area for placing the plurality of cell assemblies 100 thereon.

[0094] The base plate 420 may include a plate-shaped electrical component mounting portion 427 provided at one side end and perpendicular to the bottom surface 421. A BMS assembly 600 and a pack terminal portion 700 including electrode terminals of the battery pack 10, a fuse, etc. may be attached to the outer surface of the electrical component mounting portion 427. The pack terminal portion 700 may be configured to be exposed or shielded using a terminal cover 701 detachably provided on the pack cover 410.

[0095] 9, the base plate 420 may include support frame portions 422 provided in edge regions extending in the arrangement direction of the cell assemblies 100 and protruding upward at predetermined intervals along the arrangement direction of the cell assemblies 100, and recesses 423 provided between adjacent support frames. Here, the arrangement direction of the cell assemblies 100 is the same as the stacking direction of the battery cells 101, and the edge regions extending in the arrangement direction of the cell assemblies 100 include edge regions in the -X direction and the +X direction of the base plate 420 in FIG.

[0096] 10, the support frame portion 422 has an outer surface that is recessed inward. The recessed shape is generally U-shaped, and this shape is compatible with the rod member 500 described below. However, the recessed shape does not necessarily have to be U-shaped, as long as it is compatible with the rod member.

[0097] The recess 423 may be located between two adjacent support frame portions 422 as shown in Fig. 10. The recess 423 may also be configured to fit a shape of the mounting guide block 315 of the bus bar frame 310 as shown in Fig. 11.

[0098] Next, the assembly structure and fixing structure between the base plate 420 and the plurality of cell assemblies 100 will be described with reference to FIGS.

[0099] Each cell assembly 100 includes a bus bar frame assembly 300 having mounting guide blocks 315, and a base plate 420 having recesses 423 at regular intervals. The number of mounting guide blocks 315 provided on the cell assembly 100 is the same as the number of recesses 423 provided on the base plate 420. The recesses 423 may be configured on edge regions of the base plate 420 so that, when the mounting guide blocks 315 of each cell assembly 100 are inserted into the corresponding recesses 423, the cell assemblies 100 are positioned at regular intervals from one another on the base plate 420. Each cell assembly 100 also includes a mounting plate 314 that may be positioned facing the upper surface of the support frame portion 422.

[0100] Since the battery pack 10 according to the present invention includes the above-described configuration, when each cell assembly 100 is assembled to the base plate 420 so that the placement guide block 315 and the recess 423 fit together, each of the multiple cell assemblies 100 can be easily positioned in a fixed position relative to the base plate 420, as shown in FIG. 11 .

[0101] 11. Furthermore, each cell assembly 100 can be fixed in the ±Y directions relative to the base plate 420 in FIG. 11, since the mounting guide block 315 is inserted to fit into the recess 423 between the two support frame portions 422.

[0102] Referring to Figure 12, when the cell assembly 100 is placed on the base plate 420 with each of the mounting guide blocks 315 inserted into the corresponding recess 423, each of the mounting guide blocks 315 and the support frame portion 422 can be configured to form a continuous assembly wall 424 along the arrangement direction of the cell assembly 100.

[0103] The outer surface of the assembly wall 424 may be recessed inward to include a rod insertion portion 424a. As shown in FIG. 12, a rod member 500 may be inserted into the rod insertion portion 424a. The rod member 500 may be formed in a pipe shape having a length corresponding to the length of the assembly wall 424. The rod member 500 is preferably made of a metal material with excellent rigidity, such as steel. The rod member 500 may be applied substantially equally to both edge regions of the base plate 420, as shown in FIG. 9.

[0104] Meanwhile, to prevent the rod member 500 from easily slipping out of the rod insertion portion 424a, a fixing bracket may be attached to the base plate 420. For example, as shown in FIG. 2, after the rod member 500 is inserted into the rod insertion portion 424a, the fixing bracket may be coupled to the support frame portion 422 of the base plate 420.

[0105] According to this embodiment, all cell assemblies 100 can be fixed in the ±X, ±Y, and ±Z directions relative to the base plate 420. That is, each cell assembly 100 is sandwiched between the support frame portions 422 of the base plate 420 (the edge regions on both sides), and movement in the ±X direction is restricted. Also, as shown in FIG. 13 , a rod member 500 is inserted inside the mounting guide block 315 of each cell assembly 100, and movement in the ±X and ±Z directions is restricted. And, as described above, the mounting guide block 315 of each cell assembly 100 is inserted into the recess 423, and movement in the ±Y direction is restricted.

[0106] Referring mainly to Figures 9, 10, and 13, a base plate 420 according to one embodiment of the present invention may include support ribs 421a that protrude in a lattice shape from a bottom surface 421 and support the cell stack so as to space it apart from the bottom surface 421, and at least one lower vent hole 425 that penetrates the bottom surface 421.

[0107] The support rib 421a may advantageously act to increase the strength of the base plate 420. In particular, the support rib 421a may include a strap support portion 421b provided to protrude further upward at a specific position than other portions. The specific position is a position corresponding to the strap members 230, 260. For example, as shown in FIG. 13 , the strap support portion 421b may be located below the first lower strap member 230b or the second lower strap member 260b. In this case, the battery cells 101 may be disposed at a predetermined distance from the bottom surface 421 of the base plate 420 without directly contacting the support rib 421a.

[0108] 13 to 15, a buffer space J1 may be provided between the cell stack and the bottom surface 421 of the base plate 420. The buffer space J1 may be used as a gas flow path when gas is emitted from a particular battery cell 101.

[0109] Meanwhile, the battery cell 101 may be a pouch-type battery cell 101, and may be a three-side sealed battery cell 101 in which the lower edge is sealed.

[0110] In addition, the pouch-type battery cell 101 may have a housing portion and an edge portion. Here, the housing portion may be specified as a portion that houses an electrode assembly formed by alternately stacking positive and negative electrode plates with separators interposed therebetween. And the edge portion may be specified as a portion that surrounds the periphery of the housing portion.

[0111] In particular, the edge portions may be sealed portions formed by heat-sealing a pouch exterior material, which is the case of the pouch-type battery cell 101. The edge portions may be located at the upper, lower, front, and rear edges of the receiving portion, respectively. In this case, all four edge portions of the pouch-type battery cell 101 may be configured as sealed portions, or some of the four edge portions may be configured as folded portions that are not sealed portions. For example, the lower edge portion E1, the front edge portion, and the rear edge portion may all be configured as sealed portions, or the upper edge portion may be configured as a folded portion of the pouch exterior material.

[0112] As described above, a pouch-type battery cell 101 with all four edges sealed is called a four-sided sealed cell, and a battery cell 101 with three edges sealed is called a three-sided sealed cell.

[0113] As shown in FIG. 15, in the battery cell 101 according to this embodiment, the cell stack can be configured so that the upper edge portion where the pouch exterior material is simply folded faces the pack cover 410, and the lower edge portion E1 where the pouch exterior material is sealed faces the base plate 420.

[0114] In the case of the pouch-type battery cell 101, if gas is generated and the internal pressure continues to increase, the sealing property weakens, the lower edge E1 opens first, and gas and high-temperature particles (active material and electrode pieces detached from the electrode assembly) may be ejected through the lower edge E1 toward the base plate 420. At this time, as described above, the buffer space J1 exists between the cell stack and the base plate 420, so that the gas, particles, etc. can be smoothly discharged.

[0115] The base plate 420 may be made of a metal material that has high rigidity and fire resistance to withstand high-temperature gases, particles, flames, etc. To enhance the fire resistance of the base plate 420, the base plate 420 may have a fire-resistant coating layer on a bottom surface 421.

[0116] Meanwhile, as described above, the plurality of cell assemblies 100 according to one embodiment of the present invention are fixed to the base plate 420 at predetermined intervals.

[0117] As a result of the plurality of cell assemblies being arranged at intervals from one another in this manner, air layers K1 exist at the locations indicated by G2, G4, and G6 in Fig. 12, i.e., between each of the cell assemblies 100. As described above, the locations indicated by G1, G3, G5, and G7 in Fig. 12 are between the first cell stack 110 and the second cell stack 120 arranged at intervals from one another in each of the cell assemblies 100, and air layers K1 exist therein. Therefore, air layers K1 always exist between each of the cell stacks constituting the battery pack 10 according to the present invention.

[0118] These air layers K1 help to limit the transfer of heat between all cell stacks included in the battery pack and can act as a path for gas transfer in the event that gas is generated in the battery cells.

[0119] In this embodiment, the pack cover 410 may include an upper vent hole 411 formed therethrough, and the base plate 420 may include a lower vent hole 425 formed therethrough. The upper vent hole 411 and the lower vent hole 425 may be formed in a vertically symmetrical structure. The upper vent hole 411, the air layer K1, and the lower vent hole 425 may all be configured to match in the vertical direction, as shown in FIGS. 14 and 15 .

[0120] The configuration of the battery pack 10 according to the present invention as described above provides the following technical effects.

[0121] 16 , if a certain battery cell 101 (hereinafter referred to as a trigger cell) among the battery cells 101 constituting the second cell stack 120 of the first cell assembly 100 experiences thermal runaway, the propagation of heat generated in the trigger cell may remain within the second cell stack 120 including the trigger cell. In addition, the propagation of heat may be blocked by the air layer K1 between the second cell stack 120 of the first cell assembly 100 and the first cell stack 110 of the first cell assembly 100, and the air layer K1 between the second cell stack 120 of the first cell assembly 100 and the first cell stack 110 of the second cell assembly 100.

[0122] In addition, if gas is generated inside the trigger cell during thermal runaway and the internal pressure rises, the seal of the pouch exterior material may be broken, causing high-temperature gas to be emitted. In this case, the battery cell 101 is arranged such that the lower edge portion having the seal faces the base plate 420, and the main direction of the gas generated in the battery cell 101 can be guided toward the base plate 420.

[0123] As described above, the battery pack 10 according to this embodiment has a buffer space J1 between the bottom surface 421 of the base plate 420 and the cell stack, and the buffer space J1 functions as a gas venting path. Furthermore, the battery pack 10 includes an air layer K1 between the first cell stack 110 and the second cell stack 120 of each cell assembly 100 and an air layer K1 between two adjacent cell assemblies 100. An upper portion of each air layer K1 is configured to communicate with an upper vent hole 411 of the pack cover 410, and a lower portion of each air layer K1 is configured to communicate with a lower vent hole 425 of the base plate 420. Therefore, gas emitted from the battery cell 101 can be discharged to the outside of the battery pack 10 through the buffer space J1 and / or the air layer K1 and the upper vent hole 411 or the lower vent hole 425.

[0124] In particular, in the battery pack 10 according to this embodiment, the pack case 400 is provided with upper vent holes 411 and lower vent holes 425 that correspond one-to-one to the buffer space J1 between the cell stack and the bottom surface 421 of the base plate 420 and the air layer K1 between the cell stacks 110 and 120. Therefore, high-temperature and high-pressure gas generated in the battery cells 101 can be uniformly dispersed and discharged to the outside of the pack case 400. As a result, even if gas is ejected from the battery cells 101, collapse or deformation of the battery pack 10 can be prevented.

[0125] Meanwhile, an energy storage device according to the present invention may be configured to include one or more of the battery packs 10 described above.

[0126] The energy storage device may further include a master battery management system for controlling the battery packs in an integrated manner.

[0127] Although the present invention has been described above using limited embodiments and drawings, the present invention is not limited to these, and it goes without saying that various modifications and variations can be made by a person having ordinary knowledge in the technical field to which the present invention pertains within the technical spirit of the present invention and the scope of equivalents of the claims.

[0128] Meanwhile, although directional terms such as up, down, left, right, front, and rear are used in this specification, it will be obvious to those skilled in the art of the present invention that these terms are used merely for ease of explanation and may differ depending on the position of the object in question, the position of the observer, etc. [Explanation of symbols]

[0129] 10 Battery Pack 100 Cell Assembly 101 Pouch-type battery cell 102 Electrode Lead 110 First cell stack 120 second cell stack 200 Cell pressing unit 201 Rigid Plate 202 Insulation sheet 203 Compressible Pad 210 First left pressing unit 220 First right pressing unit 230 First strap member 240 Second left pressing unit 250 Second right pressing unit 260 Second strap member 300 Busbar frame assembly 310 Busbar Frame 311 Central insertion part 312 Spacing maintenance protrusion 314 Stationary Plate 315 Mounting guide block 320 Busbar 400 pack case 410 Pack Cover 411 Upper vent hole 420 base plate 421 bottom 422 Support frame part 423 Recess 424 Assembly wall 425 Lower vent hole 427 Electrical equipment mounting section 500 Rod material 600 BMS assembly 700 pack terminal part 701 Terminal cover E1 Lower edge H1 Strap fastening hole H2 hook fastening hole J1 Buffer space K1 Air Layer

Claims

1. at least one cell assembly; a pack case that houses the at least one cell assembly; Including, The cell assembly comprises: two or more cell stacks comprising stacked battery cells; cell pressing units disposed on the outermost sides of each of the cell stacks along the stacking direction of the battery cells so as to individually apply pressing forces to each of the cell stacks; bus bar frame assemblies disposed in front of and behind the cell stack in a direction intersecting the stacking direction of the battery cells, electrically connecting the battery cells, and integrally supporting two or more of the cell stacks and the cell pressing unit; Including the battery pack.

2. the battery cell is a pouch-type battery cell, the cell stack includes a first cell stack and a second cell stack arranged alongside the first cell stack at a predetermined interval from the first cell stack, The battery pack according to claim 1 , further comprising an air layer between the first stacked cell body and the second stacked cell body.

3. The cell pressing unit is a first left pressing unit facing the battery cell at the left outermost edge of the first cell stack; a first right pressing unit facing the battery cell at the right outermost edge of the first cell stack; a second left pressing unit facing the battery cell at the left outermost edge of the second cell stack; a second right pressing unit facing the battery cell at the right outermost edge of the second cell stack; 3. The battery pack of claim 2, comprising:

4. The first left pressing unit, the first right pressing unit, the second left pressing unit, and the second right pressing unit are 4. The battery pack of claim 3, wherein each of the rigid plates is made of a metal material or a reinforced plastic material that has high mechanical rigidity.

5. The first left pressing unit, the first right pressing unit, the second left pressing unit, and the second right pressing unit are an insulating sheet attached to a surface of each of the rigid plates; a compressible pad having one surface in contact with the insulating sheet and the other surface in contact with the battery cell; 5. The battery pack of claim 4, comprising:

6. 4. The battery pack according to claim 3, wherein the first right-side pressing unit and the second left-side pressing unit are arranged at a predetermined interval from each other, and an air layer is provided between the first right-side pressing unit and the second left-side pressing unit.

7. The bus bar frame assembly is a central insertion portion into which the terminal end of the first right pressing unit and the terminal end of the second left pressing unit are inserted; The central insertion portion is The battery pack according to claim 3 , further comprising a gap maintaining protrusion protruding into a space between an end portion of the first right pressing unit and an end portion of the second left pressing unit.

8. The cell pressing unit is a first strap member having one end fixedly connected to the first left-side pressing unit and the other end fixedly connected to the first right-side pressing unit, the first strap member extending across the first cell stack in the width direction and wrapping at least one of the upper and lower portions of the periphery of the first cell stack; a second strap member having one end fixedly connected to the second left-side pressing unit and the other end fixedly connected to the second right-side pressing unit, the second strap member extending across the second cell stack in the width direction and wrapping at least one of the upper and lower portions of the periphery of the second cell stack; 4. The battery pack of claim 3, further comprising:

9. The bus bar frame assembly is a bus bar frame made of an electrically insulating material and sized to cover the front or rear surfaces of the first cell stack and the second cell stack; a plurality of bus bars made of a metal material, attached to the bus bar frame, and connected to electrode leads of the battery cells; 4. The battery pack of claim 3, comprising:

10. the at least one cell assembly is a plurality of cell assemblies arranged side by side; The pack case is a base plate supporting the plurality of cell assemblies below the plurality of cell assemblies; a pack cover that covers the plurality of cell assemblies and interconnects with the base plate; 10. The battery pack of claim 1, comprising:

11. The base plate is support frame portions provided in edge regions extending in the arrangement direction of the cell assemblies, protruding upward at predetermined intervals along the arrangement direction of the cell assemblies, and configured to support the bus bar frame assemblies of each of the cell assemblies; a recess provided between adjacent support frame portions; Including, The bus bar frame assembly of each of the cell assemblies is a mounting plate disposed on an upper surface of the support frame; a mounting guide block protruding downward from the mounting plate so as to be insertable into the corresponding recess; 11. The battery pack of claim 10, comprising:

12. the cell assembly is configured such that when each of the mounting guide blocks is inserted into the corresponding recess and placed on the base plate, each of the mounting guide blocks and the support frame portion form a continuous assembly wall along the arrangement direction of the cell assemblies, The assembly wall body includes a rod insertion portion having an outer surface concave inward, The battery pack according to claim 11 , wherein a rod member having a length corresponding to a length of the wall assembly is inserted into the rod insertion portion.

13. the battery cell is a pouch-type battery cell, The pouch-type battery cell accommodates an electrode assembly and includes a pouch exterior material having a lower edge, a front edge, and a rear edge heat-sealed thereto; the cell stack is arranged such that the lower edge portion of the pouch exterior material faces the base plate, The base plate is support ribs that protrude in a grid pattern from the bottom surface and support the cell stack so as to space it apart from the bottom surface; At least one vent hole formed through the bottom surface; 11. The battery pack of claim 10, comprising:

14. the cell stacks are arranged at predetermined intervals along a stacking direction of the battery cells, and an air layer is formed between the cell stacks; the pack cover has an upper vent hole formed therethrough; the base plate has a lower vent hole formed therethrough; The battery pack according to claim 10 , wherein the upper vent hole, the air layer, and the lower vent hole are all configured to match in the vertical direction.

15. 15. An energy storage device comprising the battery pack of any one of claims 1 to 14.

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