Battery module, battery pack including the battery module, and energy storage system

Abstract

A battery module according to one embodiment of the present invention includes a cell stack formed by stacking a plurality of battery cells, each having a receiving portion that receives an electrode assembly, and first and second edge portions along a longitudinal direction of the receiving portion and a third and fourth edge portion along a width direction of the receiving portion, in such a manner that the receiving portions face each other in a vertical direction, and the battery cells each have a resealed portion in the first edge portion and a sealed portion or an unsealed portion in the second edge portion, and the first and second edge portions are alternately positioned on both sides of the cell stack in the vertical direction.

Description

[Technical Field]

[0001] The present invention relates to a battery module, a battery pack including the battery module, and an energy storage system (ESS), and more particularly to a fire-preventing battery module, a battery pack including the battery module, and an ESS. This application claims priority to Korean Patent Application No. 10-2022-0130431 filed on October 12, 2022, and Korean Patent Application No. 10-2023-0060685 filed on May 10, 2023, the entire contents of which are incorporated herein by reference in their entirety. [Background technology]

[0002] As technological development and demand for various mobile devices, electric vehicles, ESS, etc. has increased significantly, interest in and demand for secondary batteries as energy sources has skyrocketed. While nickel-cadmium batteries and nickel-metal hydride batteries have traditionally been used as secondary batteries, lithium secondary batteries have recently been widely used because they have almost no memory effect compared to nickel-based secondary batteries, can be freely charged and discharged, have a very low self-discharge rate, and have a high energy density.

[0003] Lithium secondary batteries mainly use lithium-based oxides and carbon materials as positive and negative electrode active materials, respectively, and include an electrode assembly in which a positive electrode plate coated with the positive electrode active material and a negative electrode plate coated with the negative electrode active material are arranged with a separator interposed therebetween, and an exterior material, such as a battery case, that hermetically houses the electrode assembly together with an electrolyte.

[0004] Generally, secondary batteries can be classified into can-type batteries in which an electrode assembly is housed in a metal can and pouch-type batteries in which an electrode assembly is housed in a pouch made of an aluminum laminate sheet, depending on the shape of the exterior material.

[0005] In recent years, battery packs have been widely used for driving and ESS applications in medium- to large-sized devices such as electric vehicles and ESSs. A battery pack includes one or more battery modules housed within a pack case and a control unit that controls the charging and discharging of the battery pack. Here, a battery module is configured to include multiple battery cells housed within a module housing. That is, in the case of a battery pack, multiple battery cells (secondary batteries) are housed within a module housing to form each battery module, and one or more such battery modules are housed within a pack case to form a battery pack. In particular, pouch-type battery cells have various advantages, such as being lightweight and having little dead space when stacked, but have problems such as being vulnerable to external impacts and being somewhat difficult to assemble. Therefore, battery packs are generally manufactured by first modularizing multiple battery cells and then housing them within a pack case.

[0006] While pouch-type battery cells have excellent electrical properties, they can suffer from the problem of swelling, which occurs when the active material and electrolyte, which are components of the battery, decompose under abnormal operating conditions such as overcharging, over-discharging, exposure to high temperatures, or electrical short circuits, generating heat and gas, causing the secondary battery to expand. Swelling accelerates this decomposition reaction and can lead to battery cell explosion and fire due to thermal runaway.

[0007] In other words, when a battery cell experiences thermal runaway, it generates a flare, which is a flame that shoots out like a flash from a vulnerable sealing part, a spark, which is a high-heat particle released when the internal electrode detaches and the aluminum current collector melts, and high-temperature vent gas.In particular, these do not remain in the affected area but can travel to surrounding modules, including nearby battery cells, making them more likely to lead to a major accident.

[0008] In the field of conventional battery fire prevention, the most common technology is to block sparks and flames using physical barriers, treating the directional venting of battery cells as non-existent in terms of the direction of the flame. Also, when solving battery fires through this method, changing only the blocking method without adjusting the placement of the heat source has reached its limit in solving thermal propagation when energy density increases. Summary of the Invention [Problem to be solved by the invention]

[0009] The present invention has been made to solve the above problems, and an object of the present invention is to provide a battery module that can prevent battery fires, particularly explosive fires accompanied by auto ignition.

[0010] Another object of the present invention is to provide a battery pack and an ESS having increased safety by including the above-described fire-preventing battery module. [Means for solving the problem]

[0011] In order to solve the above problems, a battery module according to one aspect of the present invention includes a cell stack formed by stacking a plurality of battery cells, each having a housing portion that houses an electrode assembly, and first and second edge portions along the longitudinal direction of the periphery of the housing portion, and third and fourth edge portions along the width direction of the periphery of the housing portion, with the housing portions facing each other in an up-down direction, and the battery cells each having a resealing portion at the first edge portion and a sealed portion or an unsealed portion at the second edge portion, and the first and second edge portions are alternately positioned on both sides of the cell stack in the up-down direction.

[0012] A battery module according to an embodiment of the present invention may further include a module housing that accommodates the cell stack, and the module housing may include a pair of side plates located on both sides of the cell stack, and the side plates may be spaced apart from the cell stack to form a space.

[0013] The module may further include a polycarbonate (PC) sheet and a mica sheet between the module housing and the side of the cell stack.

[0014] The first edge portions of approximately half of the battery cells among the plurality of battery cells may face one of the side plates, and the first edge portions of the remaining battery cells among the plurality of battery cells may face the other of the side plates.

[0015] A battery module according to another embodiment of the present invention further includes a module housing that accommodates the cell stack, and the module housing includes a pair of side plates located on both sides of the cell stack and a top plate that covers an upper portion of the cell stack, and the side plates may be thicker than the top plate.

[0016] A battery module according to yet another embodiment of the present invention further includes a module housing that accommodates the cell stack, and the module housing includes a pair of side plates located on both sides of the cell stack and a top plate that covers an upper portion of the cell stack, and the side plates may be made of a material having a higher specific heat than the top plate.

[0017] A battery module according to yet another embodiment of the present invention may further include a module housing that accommodates the cell stack, the module housing including a pair of side plates located on both sides of the cell stack, and heat dissipation fins may be formed on the outer sides of the side plates.

[0018] A battery module according to still another embodiment of the present invention may further include a thermal spreader between the module housing and a side surface of the cell stack.

[0019] The battery module according to the embodiment of the present invention may further include a buffer pad located on at least one of an upper side and a lower side of the cell stack.

[0020] The battery module according to the embodiment of the present invention may further include an insulating plate located on at least one of an upper side and a lower side of the cell stack.

[0021] The module housing may further include a base plate supporting the cell stack and a top plate covering an upper portion of the cell stack, and the base plate may have a U-frame structure capable of wrapping and fixing a lower end of the side plate from the outside.

[0022] Here, the top plate and the side plates may be connected to each other to form a U-frame structure.

[0023] A battery module according to an embodiment of the present invention may further include a module housing that accommodates the cell stack, the module housing including a pair of side plates located on both sides of the cell stack and a top plate that covers an upper portion of the cell stack, the module housing having a module opening formed in the longitudinal direction, and the module housing may further include a bus bar frame assembly that covers the module opening.

[0024] In an embodiment of the present invention, the pair of side plates may include a pair of spark direction changeover portions formed by bending one side end portion in the longitudinal direction toward the cell stack.

[0025] Here, the module housing may further include a fastening frame that connects the pair of spark direction changers and has an open center.

[0026] In addition, the battery cells may include electrode leads at the third edge portion and the fourth edge portion, the module housing may further include a top plate covering an upper portion of the cell stack, the module housing may have a module opening formed in the longitudinal direction, and the module housing may further include a bus bar frame assembly covering the module opening, and the bus bar frame assembly may be in close contact with the spark direction switching unit and the fastening frame.

[0027] In order to solve the above problem, another aspect of the present invention provides a battery pack including the above battery module.

[0028] Furthermore, yet another aspect of the present invention provides an ESS including the above-described battery module or battery pack. [Effects of the Invention]

[0029] According to one aspect of the present invention, when stacking battery cells to manufacture a battery module, battery pack, or the like, the reseal is stacked in a zigzag pattern to prevent the reseal from being biased in only one direction. Zigzag stacking positions the seal on both sides of the cell stack, i.e., in both directions. The reseal, which has a relatively weak seal, opens, enabling directional venting or thermal energy dispersion in both directions. This allows high-temperature, high-pressure flares emitted by numerous sparks or thermal runaway of battery cells to disperse and reduce pressure, lowering the temperature of the outer wall of the battery module or battery pack to below 500°C, thereby preventing spontaneous combustion and explosions that may occur when hydrogen and oxygen in the surrounding vent gas come into contact.

[0030] Furthermore, according to one aspect of the present invention, by improving the module housing, the temperature of the side plate in the module housing can be controlled to 500°C or less even when vent gas is discharged through the resealing section. This effectively prevents spontaneous combustion caused by contact between hydrogen and oxygen in the surrounding vent gas.

[0031] Furthermore, according to one aspect of the present invention, by improving the module housing, it is possible to block the movement of flares and sparks that occur during thermal runaway of a battery cell, thereby preventing the outbreak of a fire or the spread of flames to nearby battery modules.

[0032] The following drawings attached to this specification illustrate preferred embodiments of the present invention and, together with the detailed description of the invention, serve to further understand the technical concept of the present invention. Therefore, the present invention should not be interpreted as being limited to only the matters described in the drawings. [Brief explanation of the drawings]

[0033] [Figure 1] 1 is a perspective view of a battery cell included in a battery module according to an embodiment of the present invention; [Figure 2] 5A to 5C are views illustrating a method for manufacturing a battery cell included in a battery module according to an embodiment of the present invention. [Figure 3] 1 is a cross-sectional view of a battery module according to an embodiment of the present invention; [Figure 4] 4 is an exploded perspective view of a cell stack included in the battery module of FIG. 3. FIG. [Figure 5] FIG. 10 is an exploded perspective view showing another example of a cell stack. [Figure 6] FIG. 10 is an exploded perspective view of a cell stack according to a comparative example. [Figure 7] 4 is a diagram showing a modified example of the battery module shown in FIG. 3. FIG. [Figure 8] 4 is a diagram showing another modified example of the battery module shown in FIG. 3. FIG. [Figure 9] 4 is a diagram showing yet another modified example of the battery module shown in FIG. 3. FIG. [Figure 10] 4 is a diagram showing yet another modified example of the battery module shown in FIG. 3. FIG. [Figure 11] FIG. 10 is a perspective view of a battery module according to another embodiment of the present invention. [Figure 12] FIG. 12 is an exploded perspective view of the battery module shown in FIG. [Figure 13] 12 is an exploded perspective view of a cell stack included in the battery module of FIG. 11. FIG. [Figure 14] FIG. 12 is an exploded perspective view of some components located at the rear of the battery module in FIG. 11. [Figure 15] FIG. 12 is an exploded perspective view of some components located in the front of the battery module of FIG. 11. [Figure 16] FIG. 12 is a partial cutaway view of the battery module of FIG. 11. [Figure 17] FIG. 12 is a cross-sectional view parallel to the longitudinal direction of the battery module of FIG. [Figure 18] 1 is a schematic diagram of a battery pack including a battery module according to an embodiment of the present invention. [Figure 19] 1 is a schematic diagram of an ESS including a battery module according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0034] 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 the specification and claims should not be construed as being limited to their ordinary and dictionary meanings, but should be construed as having meanings and concepts corresponding to the technical ideas of the present invention, in accordance with the principle that the inventors themselves can appropriately define the concepts of terms in order to best explain the invention.

[0035] Therefore, it should be understood that the embodiments described in this specification and the configurations shown in the drawings are merely the most preferred embodiments of the present invention and do not represent the entire technical idea of ​​the present invention, and that there may be various equivalents and modifications that can be substituted therefor at the time of this application.

[0036] FIG. 1 is a perspective view of a battery cell included in a battery module according to an embodiment of the present invention.

[0037] 1, the battery cell 10 includes a pouch exterior material 20 and an electrode assembly (not shown), and a pair of electrode leads 30 protrude outside the pouch exterior material 20. The battery cell 10 also includes a sealing portion 40 and a resealing portion 50. Thus, the battery cell 10 is a pouch-type battery cell.

[0038] Here, the electrode assembly may be, but is not limited to, a jelly-roll type assembly in which a separator is interposed between a long sheet-shaped positive electrode and a negative electrode and the assembly is wound up; a stack type assembly in which rectangular positive electrodes and negative electrodes are stacked with a separator sandwiched between them; a stack-folding type assembly in which unit cells are wound up with a long separating film; or a lamination-stack type assembly in which battery cells are stacked with a separator sandwiched between them and attached to each other.

[0039] Furthermore, it is needless to say that the electrolyte may be replaced with a solid electrolyte or a quasi-solid electrolyte in a gel state that is intermediate between a liquid and a solid, by adding an additive to a solid electrolyte, in addition to the commonly used liquid electrolyte.

[0040] The electrode assembly described above is housed in a pouch exterior material 20, which typically has a laminate sheet structure of an inner layer / metal layer / outer layer. The inner layer, which is in direct contact with the electrode assembly, must be insulating and electrolyte-resistant, and must also have sealing properties to seal the electrode assembly from the outside, i.e., excellent thermal adhesive strength at the sealed portion where the inner layers are thermally bonded together. Materials for such inner layers may be selected from polyolefin resins such as polypropylene, polyethylene, polyethylene acrylic acid, and polybutylene, which have excellent chemical resistance and sealing properties, polyurethane resins, and polyimide resins, but are not limited to these. Polypropylene is most preferred because of its excellent mechanical properties, such as tensile strength, rigidity, surface strength, and impact resistance, as well as chemical resistance.

[0041] The metal layer in contact with the internal layer corresponds to a barrier layer that prevents moisture and various gases from penetrating into the interior of the battery from the outside, and a preferred material for such a metal layer is an aluminum thin film, which is light and has excellent formability.

[0042] An outer layer is provided on the other side of the metal layer. This outer layer may be made of a heat-resistant polymer having excellent tensile strength, moisture-proof properties, and air-proof properties, so as to protect the electrode assembly while ensuring heat resistance and chemical resistance. Examples of such a material include, but are not limited to, nylon or polyethylene terephthalate.

[0043] Meanwhile, the pair of electrode leads 30 may consist of a positive electrode lead and a negative electrode lead, and may be exposed to the outside of the pouch outer casing 20 after the positive electrode tab and the negative electrode tab of the electrode assembly are electrically connected, respectively, or may be directly connected to the electrode assembly without the tabs.

[0044] The battery cell 10 may have a housing R in which an electrode assembly is housed, and edge portions E1 to E4 around the housing R. For example, the battery cell 10 may have a first edge portion E1 and a second edge portion E2 along the longitudinal direction (X-axis direction in the drawing), and a third edge portion E3 and a fourth edge portion E4 along the width direction (Y-axis direction in the drawing). In this way, the battery cell 10 may have four edge portions E1 to E4. In this embodiment, the electrode lead 30 is included in the third edge portion E3 and the fourth edge portion E4. In the pouch exterior material 20, the distance between both ends from which the electrode lead 30 protrudes may be defined as the longitudinal direction of the battery cell 10. In this way, the electrode lead 30 may be provided at both front and rear ends of the battery cell 10 in the longitudinal direction, i.e., at the front and rear ends of the battery cell 10.

[0045] The first edge portion E1 includes a resealed portion 50. The third edge portion E3 and the fourth edge portion E4 include sealed portions 40. In the case of a four-sided sealing method, the second edge portion E2 also includes a sealed portion 40. In the case of a three-sided sealing method, only the second edge portion E2 may include an unsealed portion. Here, the unsealed portion refers to a portion where the pouch outer material is folded. The drawings illustrate a four-sided sealing method. Therefore, the first edge portion E1 includes a resealed portion 50, and the second edge portion E2, the third edge portion E3, and the fourth edge portion E4 include sealed portions 40.

[0046] The sealing portion 40 is a portion to which the pouch exterior material 20 is joined to seal the periphery of the storage portion R. The resealing portion 50 refers to a sealing portion generated in a resealing operation performed after the degassing process of the battery cell 10.

[0047] When constructing a battery module or battery pack using battery cells, the battery module size can be minimized to reduce the space occupied by the battery cells within the device and increase space utilization, or the electrode assembly size can be increased by minimizing the area occupied by the sealing portion for a given battery module size and using the excess space. For the latter, dimensions are often controlled by folding the sealing portion located on the side of the battery cell to form a folding portion. In the illustration, the resealing portion 50 at the first edge E1 and the sealing portion 40 at the second edge E2 are folded. However, simply folding the folding portion itself can cause cell swelling due to springback, so the folding portion can be taped to prevent this. Reference numeral 60 denotes a taping member.

[0048] A plurality of the above-described battery cells 10 may be stacked along the Z-axis direction to form a battery module. Because the battery cells 10 have a flat shape along the XY plane, the battery cells 10 are very advantageous for densely stacking along the Z-axis direction.

[0049] FIG. 2 is a view for explaining a method of manufacturing a battery cell included in a battery module according to an embodiment of the present invention.

[0050] The battery cell 10 is manufactured through a process of assembling a secondary battery, a process of activating the secondary battery, and the like.

[0051] The pouch outer casing 20 may be composed of a lower outer casing in which the electrode assembly is housed and an upper outer casing that seals the upper part of the lower outer casing. In the four-sided sealing type, the lower outer casing and the upper outer casing are two separate sheets. In the three-sided sealing type, the pouch outer casing, which is a single sheet, may be folded to form the lower outer casing and the upper outer casing.

[0052] After the electrode assembly is accommodated in the accommodation portion R of the lower exterior material, the periphery of the accommodation portion R of the lower exterior material is brought into close contact with the corresponding periphery of the upper exterior material, and the adhered portion is heat-sealed. After that, an electrolyte is injected, and the remaining portion is vacuum-sealed to assemble the secondary battery. The accommodation portion R may also be formed in the upper exterior material. The four-sided sealing method means that all four edge portions E1 to E4 become the sealing portion 40.

[0053] During the activation process, the secondary battery is mounted in a designated jig to ensure smooth current flow, and charging and discharging are performed under the conditions required for activation. Due to the characteristics of secondary batteries, this activation process must be performed first to activate the positive electrode active material during the first cycle and to form a stable surface film (SEI: Solid Electrolyte Interface) on the negative electrode. During the activation process, a large amount of gas is generated inside the secondary battery. The generated gas is then removed through an opened or cut exhaust port, and the gas exhaust area is resealed by heat sealing. The process of venting the gas inside the secondary battery and heat sealing the exhaust port is generally referred to as the degassing process. The resealed area is the resealed portion 50. In this embodiment, the resealed portion 50 is included in the first edge portion E1. The excess pouch outer casing 20 outside the resealed portion 50 is cut and removed.

[0054] The inventors discovered that because the resealing portion 50 of the first edge portion E1 is formed by resealing after a degassing process, it has lower seal strength during thermal runaway than the sealing portion 40 of the second edge portion E2 on the opposite side, and is therefore more likely to break first. The inventors also discovered that if the resealing portions 50 are concentrated on one side when multiple battery cells 10 are housed in a module housing, an aluminum-cased module housing may melt. Furthermore, the inventors discovered that if the resealing portions 50 are concentrated on one side when multiple battery cells 10 are housed, a steel-based module housing may not melt, but the temperature of the outer wall may reach 800°C or higher. If hydrogen contained in the vent gas flowing nearby exceeds 505°C, it is likely to mix with oxygen and cause an explosion. This is spontaneous combustion. The inventors realized that spontaneous combustion of a battery module can be prevented by controlling the temperature of the module housing by adjusting the location of the resealing portions 50, and thus completed the present invention.

[0055] Fig. 3 is a cross-sectional view of a battery module according to an embodiment of the present invention, showing a cross section taken along the width direction and perpendicular to the longitudinal direction of the battery cells and the battery module. Fig. 4 is an exploded perspective view of a cell stack included in the battery module of Fig. 3, and Fig. 5 is an exploded perspective view showing another example of the cell stack.

[0056] 3 to 5, the battery module 100 includes a cell stack 110 including a plurality of battery cells 10 as described above, and a module housing 120 that houses the cell stack 110. In particular, the battery module 100 has a configuration in which the reseal portions 50 of the battery cells 10 are dispersed and stacked in the cell stack 110.

[0057] A plurality of battery cells 10 are stacked in the vertical direction (the Z-axis direction in the drawing) with their housing portions R facing each other to form a cell stack 110. The vertical direction can also be referred to as the vertical direction or the Z-axis direction. In an embodiment of the present invention, the battery cells 10 are stacked so that the reseal portions 50 do not face either side. For example, within the cell stack 110, the reseal portions 50 are arranged on both sides of the width direction. For example, the reseal portions 50 are stacked in a zigzag pattern, with one reseal portion 50 located on the left side and another reseal portion 50 located on the right side along the Z-axis direction. As a result, first edge portions E1 including the reseal portions 50 and second edge portions E2 not including the reseal portions 50 are alternately positioned in the vertical direction on both sides of the cell stack 110. The second edge portions E2 include the sealed portion 40 or the unsealed portion as described above.

[0058] 4, a first edge E1 including the resealing portion 50 and a second edge E2 not including the resealing portion 50 may be alternately positioned along the vertical direction on both sides of the cell stack 110, or, as shown in FIG. 5, a plurality of first edge E1 including the resealing portion 50 and a plurality of second edge E2 not including the resealing portion 50 may be alternately positioned. For example, as shown in FIG. 5, two or more may be alternately positioned.

[0059] In any case, preferably, the reseal portions 50 are distributed alternately on the left and right wall surfaces (located on both sides in the width direction) of the module housing 120, with the plurality of battery cells 10 stacked alternately. This significantly reduces the pressure and temperature concentrated on both wall surfaces of the module housing 120 within the cell stack 110. For example, if the number of battery cells 10 is 2n, the reseal portions 50 of n battery cells 10 are disposed on the left wall surface, and the reseal portions 50 of the remaining n battery cells 10 are disposed on the right wall surface. If the number of battery cells 10 is 2n+1, the reseal portions 50 of n or n+1 battery cells 10 are disposed on the left wall surface, and the reseal portions 50 of the remaining n+1 or n battery cells 10 are disposed on the right wall surface.

[0060] Even if the first edge portions E1 and the second edge portions E2 are alternately stacked in the vertical direction in this manner, the third edge portions E3, the fourth edge portions E4, or the third edge portion E3 and the fourth edge portion E4 are vertically aligned from the front and rear, so that the electrode leads 30 can be stacked in a vertically aligned line at the front and rear of the cell stack 110. It will be understood that the polarities of the electrode leads 30 located at the front may all be the same or may be opposite polarities located in the vertical direction. It will also be understood that some battery cells 10 may be stacked upside down, taking into account the polarity of the electrode leads 30 and the arrangement of the reseal portion 50.

[0061] The module housing 120 shown in Fig. 3 has an internal space capable of accommodating the battery cells 10 therein, and serves to provide mechanical support for the accommodated battery cells 10 and protect them from external impacts, etc. Referring further to Fig. 3, the module housing 120 includes a pair of side plates 130 located on both sides of the cell stack 110. The module housing 120 may further include a top plate 140 that covers the top of the cell stack 110, and a base plate 150 that supports the cell stack 110.

[0062] The side plates 130 and the cell stack 110 may be spaced apart to form a space S. Such a space S may be configured to contain flares and sparks that are ejected during swelling. For example, the pair of side plates 130 may be spaced apart and opposed to each other at a distance slightly wider than the width W of the cell stack 110 to form the space S.

[0063] The battery module 100 may further include a PC sheet 160 and a mica sheet 170. The PC sheet 160 and the mica sheet 170 may be included between the module housing 120 and the side of the cell stack 110. In particular, in this embodiment, the PC sheet 160 and the mica sheet 170 are included between the side plate 130 and the side of the cell stack 110. The PC sheet 160 and the mica sheet 170 may be positioned on both side surfaces of the cell stack 110. The mica sheet 170 has excellent heat resistance so as to withstand high-temperature vent gas and sparks. The PC sheet 160 and the mica sheet 170 are flexible or easily deformable, and can block the propagation of the flame and heat generated by the flame to other battery cells 10 or the side plate 130 when a fire occurs in one battery cell 10.

[0064] The first edge portions E1 of approximately half of the plurality of battery cells 10 included in the cell stack 110 face the left side plate 130a, which is one of the side plates 130, and the first edge portions E1 of the remaining plurality of battery cells 10 face the right side plate 130b, which is the other side plate 130. As a result, when venting occurs through the resealing part 50 within the cell stack 110, the pressure and temperature concentrated on both side plates (130a, 130b) can be evenly distributed to both sides, and the temperature of the side plate facing the resealing part 50 can be significantly reduced compared to when the resealing part 50 is concentrated on one side.

[0065] 6 shows a comparative example of a cell stack 110' in which the reseal parts 50 are arranged in only one direction, for example, only on the left side. In this cell stack 110', all eight reseal parts 50 face one side of the module housing to form a battery module. When the reseal parts 50 are biased to one side, they may be exposed to high temperatures and pressures in a short period of time, which could lead to a gas explosion. This is because when the fragile reseal parts 50 are concentrated on one side, the temperature rise is maximized, which can lead to spontaneous combustion and explosion when they come into contact with flammable and explosive vent gas.

[0066] Because the resealed portion 50 is formed by resealing after the degassing process, it is more fragile than the sealed portion 40 or the unsealed portion on the opposite side, and may be the first to break in the event of thermal runaway. If the resealed portion 50 is concentrated on one side, as in the comparative example, an aluminum module housing would melt, and even if a steel module housing did not melt, the temperature of the outer wall would rise to over 800°C. When the hydrogen contained in the vent gas flowing nearby exceeds 505°C, it mixes with oxygen and explodes, causing spontaneous combustion. Therefore, a battery module including the cell stack 110′ of the comparative example is vulnerable to fire.

[0067] Meanwhile, in the cell stack 110 included in the battery module 100 according to one embodiment of the present invention, the placement of the reseal parts 50 is adjusted to prevent spontaneous combustion. In the present invention, when stacking battery cells 10 to manufacture a battery module 100 or a battery pack including the battery module 100, i.e., when manufacturing the cell stack 110, the reseal parts 50 are stacked in a zigzag pattern to prevent the reseal parts 50 from concentrating on one side. In the zigzag stacking, the reseal parts 50 are arranged in two parallel directions while facing each other. The reseal parts 50 on both sides open before the sealed parts 40 or unsealed parts. Since the reseal parts 50 are arranged on both sides, directional venting in both directions can be achieved. Furthermore, thermal energy can be dispersed in both directions. This allows high-temperature and high-pressure flares emitted from a large number of sparks and thermal runaway of the battery cells 10 to be dispersed, reducing pressure and lowering the temperature of the outer wall of the module housing 120 to below 500°C. Therefore, spontaneous combustion and explosion caused by contact between hydrogen and oxygen in the surrounding vent gas can be prevented.

[0068] 3 shows that the base plate 150, the top plate 140, and the pair of side plates 130 are manufactured separately and then coupled together, but the base plate 150 and the pair of side plates 130, or the top plate 140 and the pair of side plates 130, may be manufactured integrally and then assembled. The base plate 150, the top plate 140, and the pair of side plates 130 may all be made of the same material. Also, FIG. 3 shows the shapes of the base plate 150, the top plate 140, and the pair of side plates 130 in a simplified conceptual manner. The effect of the distributed arrangement of the resealing portion 50 can be maximized by combining it with various embodiments of the module housing 120, which will be described later.

[0069] FIG. 7 shows a modification of the battery module 100 shown in FIG. 3, which includes an improved module housing 120. In this embodiment, the thickness d2 of the side plate 130 is greater than the thickness d1 of the top plate 140 (d1 <d2)。

[0070] Due to the structure of the cell stack 110, vent gas discharged from the resealing portion 50 first collides with the side plate 130. The change in heat quantity of the side plate 130 due to the vent gas is Qin (heat quantity entering the side plate 130) - Qout (heat quantity leaving the side plate 130), which can be said to be equal to Cp x M x ΔT. Here, Cp is the specific heat of the side plate 130, M is the mass of the side plate 130, and ΔT is the temperature change. When Qin - Qout is constant, increasing M can reduce ΔT. In other words, increasing the thickness d2 of the side plate 130 can increase M and reduce the temperature change. However, excessively increasing the thickness d2 of the side plate 130 is undesirable because it increases material costs and the weight of the entire battery module 100. Increasing the thickness d2 of the side plate 130 within a reasonable budget is recommended. For example, if the thickness of the module housing 120 currently in use is 1.6 mm, the thickness d2 of the side plate 130 may be set to a greater value, such as 1.8 mm. Furthermore, in order to maintain overall material costs and weight, the thickness d2 of the side plate 130 may be increased, and the top plate 140 may be configured with a reduced thickness d1. In this manner, in the battery module 100 of FIG. 7, the thickness d2 of the side plate 130 is thicker than the thickness d1 of the top plate 140. For example, the thickness d1 of the top plate 140 may be set to 1.6 mm, and the thickness d2 of the side plate 130 may be set to a greater value, such as 1.8 mm.

[0071] The thickness d1 of the top plate 140 and the thickness d2 of the side plate 130 may be determined taking into consideration various conditions such as material cost, weight, fire prevention, durability, etc. If the top plate 140 and the side plate 130 are made of the same material, the thickness d2 may also be determined taking into consideration factors such as thermal stress and thermal deformation that may occur due to the difference in thickness. For example, the thickness d2 of the side plate 130 may be determined to be 5% to 50% thicker than the thickness d1 of the top plate 140.

[0072] Increasing the thickness d2 of side plate 130 to increase M of side plate 130 in this manner allows the temperature of side plate 130 to be controlled to be 500°C or less even when vent gas is discharged through resealing portion 50. This effectively prevents spontaneous combustion caused by contact between hydrogen and oxygen in the surrounding vent gas.

[0073] 8 shows another variation of the battery module 100 shown in FIG. 3, which includes an improved module housing 120. In this embodiment, the side plates 130 include a material having a higher specific heat than the top plate 140. That is, the top plate 140 and the side plates 130 are made of different materials, and the side plates 130 have a higher specific heat.

[0074] As described above, due to the structure of the cell stack 110, the vent gas discharged from the resealing portion 50 first collides with the side plate 130. Regarding the change in heat quantity of the side plate 130 due to vent gas (Qin - Qout = Cp × M × ΔT), if Qin - Qout is constant, increasing Cp can reduce ΔT. In other words, increasing the specific heat of the side plate 130 can reduce temperature change. However, excessively increasing the specific heat of the side plate 130 is not desirable due to increased material costs and the difficulty of selecting an appropriate material. The specific heat of the side plate 130 can be increased within a reasonable budget. For example, if the currently used module housing 120 contains a material with a specific heat of 0.461 (J / gC), the specific heat of the side plate 130 should be higher, such as 0.48 to 0.5 (J / gC).

[0075] Furthermore, if the cost of alloys for increasing the specific heat increases, the specific heat of the top plate 140 may be decreased by the increased specific heat of the side plate 130 in order to maintain overall material costs. In this manner, in the battery module 100 of Fig. 8, the specific heat of the side plate 130 is configured to be higher than the specific heat of the top plate 140. For example, the specific heat of the side plate 130 may be increased by configuring the top plate 140 as a galvanized steel plate and the side plate 130 to further include a metal, such as aluminum, titanium, magnesium, or silicon, which has a higher specific heat than zinc or iron, in the form of an alloy or plating.

[0076] In this way, by increasing the specific heat of side plate 130 and controlling the heat quantity change "Qin-Qout" of side plate 130 to reduce ΔT, the temperature of side plate 130 can be controlled to be 500°C or less even when vent gas is discharged through resealing portion 50. Therefore, spontaneous combustion caused by contact between hydrogen and oxygen in the surrounding vent gas can be effectively prevented.

[0077] 9 shows yet another modification of the battery module 100 shown in FIG. 3, which includes an improved module housing 120. In this embodiment, heat dissipation fins 135 are formed on the outer side of the side plate 130.

[0078] As mentioned above, due to the structure of the cell stack 110, the vent gas discharged from the resealing unit 50 first collides with the side plate 130. In this embodiment, the side plate 130 includes heat dissipation fins 135, which allow heat to be dissipated to the outside without accumulating in the side plate 130. The heat dissipation fins 135 are configured to maximize the surface area for effective heat dissipation. As a result, even when the vent gas is discharged through the resealing unit 50, the temperature of the side plate 130 can be maintained at 500°C or less, effectively preventing spontaneous combustion.

[0079] FIG. 10 shows yet another modification of the battery module 100 shown in FIG. 3, which further includes a thermal spreader 180 between the side plate 130 and the side of the cell stack 110 in this embodiment.

[0080] Here, the thermal spreader 180 refers to an object that absorbs and dissipates heat from another object through direct thermal contact. The thermal spreader 180 has a material and structure specialized for heat conduction and radiation, and can absorb heat from the heat-generating battery cells 10 and dissipate it to the surroundings. For example, the thermal spreader 180 may be a member attached to the inner side of the side plate 130 to diffuse and dissipate heat generated in the battery cells 10. The thermal spreader 180 may include a silicon, acrylic, or graphite material.

[0081] In addition to the thermal spreader 180, the battery module 100 may further include a TIM (Thermal Interface Material) layer to improve heat transfer performance between different components. The TIM layer is intended to reduce the thermal contact resistance between components. Such a TIM layer may include various thermally conductive materials such as metal, polymer, or ceramic, and may be composed of a gel type or a phase change material. For example, the TIM layer may be a thermally conductive resin called a thermal resin.

[0082] By including the thermal spreader 180, heat can be dissipated to the outside without being accumulated in the side plate 130. According to this embodiment of the present invention, it is possible to further improve the heat dissipation performance of the battery cell 10. As a result, even if vent gas is discharged through the resealing part 50, the temperature of the side plate 130 can be controlled to 500°C or less, thereby effectively preventing spontaneous combustion.

[0083] Meanwhile, the effect of the dispersed arrangement of the resealing parts 50 according to the embodiment of the present invention can be further maximized in a battery module having a spark pocket structure, which will be described later.

[0084] FIG. 11 is a perspective view of a battery module according to another embodiment of the present invention.

[0085] 11, a battery module 200 according to another embodiment of the present invention has a substantially rectangular parallelepiped outer shape and includes a module housing 220 made of a metal material. Because the battery modules 200 have a substantially rectangular parallelepiped shape, they can be arranged neatly within a pack case without wasting space.

[0086] 12 is an exploded perspective view of the battery module shown in FIG. 11, and FIG. 13 is an exploded perspective view of a cell stack included in the battery module of FIG.

[0087] 11 to 13, a cell stack 110 is housed inside a module housing 220, and the specific description of the cell stack 110 is substantially the same as in the above-described embodiment.

[0088] A plurality of battery cells 10 may be stacked face-to-face. If the surface of the pouch exterior material 20 is smooth, the plurality of battery cells 10 may easily slip due to external impact when stacked. Therefore, to prevent this and maintain a stable stack structure of the battery cells 10, an adhesive member 70 such as a pressure-sensitive adhesive such as double-sided tape or a chemical adhesive that bonds through a chemical reaction during adhesion may be attached to the surface of the pouch exterior material 20 to form the cell stack 110.

[0089] The battery module 200 may further include a buffer pad 260 located on at least one of the upper and lower sides of the cell stack 110 .

[0090] At least one buffer pad 260 is located on at least one of the upper and lower sides of the stacked battery cells 10, and may be interposed between the battery cells 10 as needed. Such a buffer pad 260 is made of a material whose volume easily changes due to an external pressure force, and may be, for example, a sponge or a nonwoven fabric.

[0091] Furthermore, the cell stack 110 may further include an insulating plate 270 located on at least one of the upper and lower sides.

[0092] The insulating plate 270 is located on at least one of the top and bottom of the stacked battery cells 10, or of course on the outside of the buffer pad 260 if the buffer pad 260 is attached, to uniformly press the entire surface of the battery cells 10 and prevent electrical conduction between the module housing 220, which is made of a metal material, and the battery cells 10. The insulating plate 270 is preferably made of plastic to reduce the weight and provide insulation for the battery module 200.

[0093] 11 and 12, the module housing 220 is composed of a pair of side plates 230 located on both sides of the cell stack 110, a top plate 240 covering the top of the cell stack 110, and a base plate 250 supporting the cell stack 110.

[0094] The battery module 200 may further include a PC sheet 160 and a mica sheet 170 between the side plate 230 and the side of the cell stack 110, as described above.

[0095] The base plate 250 has a U-frame structure that can be fixed by wrapping the lower end of the side plate 230 from the outside. The base plate 250 can be formed into a U-frame structure by bending both ends of a single plate. The bending structure can be realized by various methods, such as pressing or roll forming.

[0096] The top plate 240 and the side plates 230 may be connected to each other to form a U-frame structure. The top plate 240 and the side plates 230 may be constructed separately and then connected to each other by welding, adhesive bonding, fitting, hook fastening, or bolt fastening. Alternatively, the top plate 240 and the side plates 230 may be manufactured by bending both ends of a single plate in the same manner as the base plate 250. In this case, the side plates 230 may be configured to extend downward from both ends of the top plate 240.

[0097] The battery module 200 includes a module opening 200a formed on one side in the longitudinal direction. The module opening 200a may also be formed on the other side in the longitudinal direction of the battery module 200. Vent gas generated inside the battery module 200 may be discharged through the module opening 200a. In this embodiment, the module openings 200a are formed at the front and rear ends of the battery cells 10 in the longitudinal direction, respectively.

[0098] The battery module 200 may further include a bus bar frame assembly 290 that covers the module opening 200 a formed on one side of the module housing 220 in the longitudinal direction.

[0099] The pair of side plates 230 may include a spark direction switching portion 230 a formed by bending one side end of the side plate 230 toward the cell stack 110 .

[0100] The module opening 200a formed on one side in the longitudinal direction of the module housing 220 is formed between a pair of spark direction switching units 230a provided on each of the pair of side plates 230. The electrode leads 30 of the battery cells 10 may be exposed to the outside of the module housing 220 through the module opening 200a formed between the pair of spark direction switching units 230a.

[0101] 14 is an exploded perspective view of some components located at the rear of the battery module of FIG. 11, and FIG. 15 is an exploded perspective view of some components located at the front of the battery module of FIG.

[0102] 14 and 15, the module housing 220 may further include a fastening frame 232 that connects the pair of spark direction switching units 230a together and has an open center.

[0103] The module openings 200a provided in the module housing 220 according to the embodiment of the present invention may be formed on both sides of the module housing 220 in the longitudinal direction. In this case, the pair of spark direction switching units 230a may also be provided on both sides of the module housing 220 in the longitudinal direction.

[0104] The bus bar frame assembly 290 includes a bus bar frame 292 and at least one bus bar 294. A pair of bus bar frame assemblies 290 may be provided, in which case the pair of bus bar frame assemblies 290 covers the module opening 200a formed on one side of the module housing 220 in the longitudinal direction and the module opening 200a formed on the other side, respectively.

[0105] The bus bar frame 292 covers the module opening 200a formed in the module housing 220, has a plurality of frame slits 292a through which the electrode leads 30 of the battery cells 10 pass, and is made of an insulating material.

[0106] The bus bar frame 292 has a shape corresponding to one end and / or the other end of the module housing 220 in the longitudinal direction and is in close contact with the module housing 220. If the module housing 220 includes the fastening frame 232 as described above, the bus bar frame 292 is in close contact with the spark direction switching unit 230a and the fastening frame 232.

[0107] The busbar 294 is disposed on the outer surface of the busbar frame 292 and is coupled to the electrode leads 30 that pass through the frame slits 292a, thereby enabling electrical connection between the multiple battery cells 10. The busbar 294 may have a flat plate shape made of a metal material and include busbar slits 294a through which the electrode leads 30 pass. In this case, the busbar slits 294a and the frame slits 292a may be formed at positions corresponding to each other.

[0108] The spark direction changer 230a and the fastening frame 232 can be deformed to contain flares, sparks, etc. In this case, it is obvious that the bus bar frame 292 can also be modified to correspond to the deformed outer shape.

[0109] 16 is a partially cutaway view of the battery module of FIG. 11, and FIG. 17 is a cross-sectional view parallel to the longitudinal direction of the battery module of FIG.

[0110] 11 to 17, the assembly process of the battery module 200 including the above-mentioned configuration will be described. First, an insulating plate 270, a buffer pad 260, a plurality of battery cells 10, the buffer pad 260, and the insulating plate 270 are stacked in this order to prepare a cell stack 110, and the electrode leads 30 of the battery cells 10 are passed through the frame slits 292a of the bus bar frame 292. At this time, it should be noted that the resealing portions 50 of the battery cells 10 are distributed to the left and right as described above. Then, the electrode leads 30 are passed through the bus bar slits 294a of the bus bar 294, bent, and fixed by a known joining method such as welding.

[0111] The cell stack 110 thus prepared is housed in a form in which it is enclosed by the base plate 250, the top plate 240, and the pair of side plates 230. At this time, the top plate 240 and the pair of side plates 230 are combined to form a U-frame structure, and the U-frame encloses both sides and the top of the cell stack 110, enclosing the cell stack 110 and leaving the front, rear, and bottom open.

[0112] The base plate 250 is connected to the U-frame so as to wrap around the lower end of the side plate 230 from the outside. The connection may be by welding, but in this embodiment, an example of connection using tape 252 and bolts 254 is given.

[0113] A bus bar frame 292 is tightly attached to the spark direction switching portion 230 a and the fastening frame 232 , and the bus bar frame 292 serves to cover the module opening portion 200 a of the module housing 220 .

[0114] With particular reference to FIG. 17, the travel paths of vent gases and sparks in the battery module 200 will be described.

[0115] 17 , the battery module 200 according to the embodiment of the present invention includes the spark direction switching unit 230a as described above, thereby preventing high-temperature sparks emitted during venting of the battery cells 10 from being ejected to the outside of the module housing 220 along the longitudinal direction of the module housing 220. That is, during venting of the battery cells 10, high-temperature sparks ejected from both widthwise sides of each battery cell 10 constituting the cell stack 110, i.e., from the alternatingly arranged resealing units 50, move toward one end and / or the other end of the longitudinal direction of the battery module 200 and then change direction toward the cell stack 110 (see the direction of the dotted arrows in FIG. 17 ). Furthermore, since the flares and sparks are confined within the space defined by the spark direction switching unit 230a, they are not only prevented from being ejected to the outside, but also their movement toward the electrode leads 30 is restricted, thereby preventing direct contact with the electrode leads 30. In this manner, the spark direction switching unit 230a realizes a spark pocket structure.

[0116] If thermal runaway occurs in a particular battery cell, flares, sparks, high-pressure vent gases, and hot air are emitted, which can lead to fires and explosions if they coexist with oxygen and flammable materials. The side plate 230 of the battery module 200 according to an embodiment of the present invention prevents thermal runaway products such as flares and sparks from being emitted outside the module housing 220 and also discharges the vent gases and hot air through the module opening 200a. In this process, the air that was filled inside the module housing 220 is also discharged, preventing the generation of flames.

[0117] In the present invention, the reseal portions 50 of the battery cells 10 are stacked in a zigzag pattern to prevent the reseal portions 50 from being biased in one direction. This allows for the dispersion of a large number of sparks and high-temperature, high-pressure flares emitted from thermal runaway of the cells, thereby reducing pressure. This effectively prevents spontaneous combustion and explosions that may occur when hydrogen and oxygen in the surrounding vent gas come into contact with each other. For example, assuming that thermal runaway occurs in a specific battery cell 10 with the first edge portion E1 located on the left side and the reseal portion 50 located on the left side in FIGS. 16 and 17 , the flares and sparks are blocked and collected in the space located on the left side, particularly in the space surrounded by the left spark direction switching portion 230a. Therefore, they cannot move forward or backward, where the bus bar 294 is located, or to the right of the battery cell 10. Meanwhile, because the module housing 220 and the cell stack 110 do not maintain a perfect airtight seal, the generated vent gas is discharged through the module opening 200a near the bus bar frame 292.

[0118] As a result, even if a thermal event occurs in any one battery cell, air is discharged to the outside along with the vent gas, so there is insufficient oxygen inside the module housing 220 necessary for ignition, and flammable materials are trapped inside the module housing 220 rather than being released to the outside.Furthermore, when the air is discharged, hot air is also discharged, maintaining the temperature below the ignition point, thereby preventing the occurrence of a fire.

[0119] The inclusion of module housing 220 that realizes a spark pocket in this manner increases the fire safety of battery module 200. Furthermore, by controlling the temperature of module housing 220 to a level that does not cause spontaneous combustion through the distributed arrangement of resealing parts 50 unique to the present invention, it is possible to prevent an internal transition after thermal runaway from leading to an explosive ignition.

[0120] In addition, a battery pack including the battery modules 100 and 200 can completely block fire. The battery modules 100 and 200 having the above-described configurations can be housed in a separate pack case or can be used to form a battery pack without being housed in a separate pack case, and the battery modules and battery packs can be used in various facilities and devices including large-capacity power sources, such as ESS, electric vehicles, hybrid vehicles, and plug-in hybrid electric vehicles.

[0121] FIG. 18 is a schematic diagram of a battery pack including a battery module according to one embodiment of the present invention.

[0122] 18 , a battery pack 300 may be configured by arranging a plurality of battery modules 100, 200 adjacent to each other in the width direction. The battery pack 300 may further include a BMS (Battery Management System) assembly 310 coupled to one side of the battery modules 100, 200 in the width direction. The battery pack 300 may include a duct 320 coupled to one or both sides of the battery pack 300 in the length direction. The battery pack 300 may further include a pack case (not shown) that houses the battery modules 100, 200.

[0123] The BMS assembly 310 may be coupled to one side in the width direction of a module assembly consisting of a plurality of adjacently arranged battery modules 100, 200. Although not shown in detail, the BMS assembly 310 includes at least one BMS that controls charging and discharging of the plurality of battery modules 100, 200. The BMS assembly 310 may further include a BMS frame coupled to the BMS. The BMS frame may be fastened to the module assembly and / or the duct 320.

[0124] The duct 320 is spaced apart from the longitudinal direction of the battery modules 100, 200 so that a pack flow path (not shown) is formed between the battery modules 100, 200 and the duct 320. In particular, in the case of the battery module 200, the duct 320 is spaced apart from the module opening 200a. The duct 320 has duct openings formed on one or both sides in the width direction. The duct openings are connected to the pack flow path. Therefore, the vent gas discharged to the outside of the battery module 200 along the module opening 200a formed in the battery module 200 moves to one or both sides in the width direction of the duct 320 along the pack flow path and is discharged to the outside of the battery pack 300 through the duct openings.

[0125] ESS, which has recently been attracting attention, is a device that can maximize power usage efficiency by storing produced electricity in batteries and supplying it to consumers when electricity is needed. An ESS is configured such that a plurality of battery modules form one rack, and tens to hundreds of racks are combined to form a single system. The ESS can also be used in conjunction with an uninterruptible power supply (UPS) that provides stable power supply in response to sudden power supply interruptions or abnormalities, and a solar power generation system that converts sunlight into electrical energy. The battery modules 100 and 200 according to embodiments of the present invention are particularly suitable as battery modules for ESS due to their excellent fire prevention effect.

[0126] FIG. 19 is a schematic diagram of an ESS including a battery module according to an embodiment of the present invention. An ESS 400 according to an embodiment of the present invention may include battery modules 100 and 200 according to an embodiment of the present invention. Furthermore, since the ESS 400 has a large energy capacity, it may include a plurality of battery modules 100 and 200 according to an embodiment of the present invention, electrically connected to each other. The ESS 400 according to an embodiment of the present invention may further include various other components of an ESS known at the time of filing of the present invention. Furthermore, the ESS 400 may be used in various locations and devices, such as smart grid systems and electric charging stations. In particular, the ESS 400 according to an embodiment of the present invention may be a residential (building) ESS for home or office use used to store energy in a home, office, or building.

[0127] Meanwhile, although terms indicating directions such as up, down, left, right, front, and rear are used in this specification, it will be obvious to those skilled in the art that these terms are used for the convenience of explanation and may vary depending on the position of the object in question, the position of the observer, etc.

[0128] 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 equivalent scope of the claims. [Explanation of symbols]

[0129] 10: Battery cell 40: Sealing part 50:Resealing part 100, 200: Battery module 110: Cell stack 120, 220: Module housing 130, 230: Side plate 135: Heat dissipation fin 140, 240: Top plate 150, 250: Base plate 160: PC sheet 170: Mica sheet 180: Thermal spreader 230a: Spark direction switching unit 232: Fastening frame 260: Buffer pad 270: Insulation plate 290: Busbar frame assembly 292: Busbar frame 294: Busbar 300: Battery pack 400:ESS

Claims

1. a cell stack formed by stacking a plurality of battery cells, each having a receiving portion in which an electrode assembly is received, a first edge portion and a second edge portion along a longitudinal direction of a periphery of the receiving portion, and a third edge portion and a fourth edge portion along a width direction of a periphery of the receiving portion, in a vertical direction with the receiving portions facing each other; the battery cell includes a resealed portion at the first edge portion, and the second edge portion includes a sealed portion or an unsealed portion; the first edge portions and the second edge portions are alternately positioned on both sides of the cell stack along the vertical direction.

2. further comprising a module housing that houses the cell stack; the module housing includes a pair of side plates located on both sides of the cell stack, The battery module according to claim 1 , wherein the side plate and the cell stack are spaced apart to form a space.

3. The battery module according to claim 2 , further comprising a polycarbonate sheet and a mica sheet between the module housing and a side surface of the cell stack.

4. 3. The battery module according to claim 2, wherein first edge portions of approximately half of the plurality of battery cells face one of the side plates, and first edge portions of the remaining battery cells face the other of the side plates.

5. further comprising a module housing that houses the cell stack; 2. The battery module according to claim 1, wherein the module housing includes a pair of side plates located on both sides of the cell stack and a top plate covering an upper portion of the cell stack, and the thickness of the side plates is greater than the thickness of the top plate.

6. further comprising a module housing that houses the cell stack; 2. The battery module according to claim 1, wherein the module housing includes a pair of side plates located on both sides of the cell stack and a top plate covering an upper portion of the cell stack, the side plates being made of a material having a higher specific heat than the top plate.

7. further comprising a module housing that houses the cell stack; the module housing includes a pair of side plates located on both sides of the cell stack, The battery module according to claim 1 , wherein the side plates are formed with heat dissipation fins on outer surfaces thereof.

8. The battery module according to claim 2 , further comprising a thermal spreader between the module housing and a side surface of the cell stack.

9. The battery module of claim 1 , further comprising a buffer pad located on at least one of an upper side and a lower side of the cell stack.

10. The battery module of claim 1 , further comprising an insulating plate located on at least one of an upper side and a lower side of the cell stack.

11. The module housing further includes a base plate that supports the cell stack and a top plate that covers an upper portion of the cell stack, The battery module according to claim 2 , wherein the base plate has a U-frame structure capable of wrapping and fixing lower ends of the side plates from outside.

12. The battery module according to claim 11 , wherein the top plate and the side plates are connected to each other to form a U-frame structure.

13. The battery module further includes a module housing that houses the cell stack, the module housing includes a pair of side plates located on both sides of the cell stack and a top plate covering an upper portion of the cell stack, The module housing has a module opening formed in the longitudinal direction, The battery module according to claim 1 , wherein the module housing further comprises a bus bar frame assembly covering the module opening.

14. The battery module according to claim 2 , wherein the pair of side plates include a pair of spark direction switching portions formed by bending one side end portion in the longitudinal direction toward the cell stack.

15. The battery module according to claim 14 , further comprising a fastening frame connecting the pair of spark direction switching units and having an open center.

16. 16. The battery module of claim 15, wherein the battery cells include electrode leads at the third edge portion and the fourth edge portion, the module housing further includes a top plate covering an upper portion of the cell stack, the module housing has a module opening formed in the longitudinal direction, and the module housing further includes a bus bar frame assembly covering the module opening, the bus bar frame assembly being in close contact with the spark direction switching unit and the fastening frame.

17. A battery pack comprising the battery module according to any one of claims 1 to 16.

18. 17. An energy storage system comprising a battery module according to any one of claims 1 to 16.

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