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: Energy Storage System), and more particularly, to a fire prevention battery module, a battery pack including the battery module, and an ESS. This application claims priority based on 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, and all the contents disclosed in the specifications and drawings of the applications are incorporated into this application.

Background Art

[0002] As the technology development and demand for various mobile devices, electric vehicles, ESS, etc. have greatly increased, the interest and demand for secondary batteries as an energy source have been rapidly increasing. Conventionally, nickel cadmium batteries or nickel metal hydride batteries have been mainly used as secondary batteries. However, in recent years, lithium secondary batteries that hardly exhibit a memory effect, can be freely charged and discharged, have a very low self-discharge rate, and have a high energy density have been widely used compared to nickel-based secondary batteries.

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

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

[0005] In recent years, battery packs have been widely applied to medium- and large-sized devices such as electric vehicles and ESSs (Electrical Systems) for propulsion and ESS use. A battery pack includes one or more battery modules and a control unit for controlling the charging and discharging of the battery pack inside a pack case. Here, a battery module is configured to contain multiple battery cells inside a module housing. In other words, in the case of a battery pack, multiple battery cells (secondary batteries) are housed inside a module housing to constitute each battery module, and one or more such battery modules are housed inside a pack case to constitute a battery pack. In particular, pouch-type battery cells have various advantages such as being lightweight and having little dead space when stacked, but they have problems such as being vulnerable to external shocks and being somewhat difficult to assemble. Therefore, it is common to manufacture battery packs in a form in which multiple battery cells are first modularized and then housed inside a pack case.

[0006] While pouch-type battery cells possess excellent electrical properties, they have a problem in that abnormal operating conditions such as overcharging, over-discharging, high-temperature exposure, and electrical short circuits can trigger decomposition reactions in the active material and electrolyte, generating heat and gas, which causes the secondary battery to expand—a phenomenon known as swelling. The swelling phenomenon can accelerate these decomposition reactions, potentially leading to thermal runaway and explosion and ignition of the battery cell.

[0007] In other words, when a battery cell experiences thermal runaway, it generates flares (flames that shoot out like a flash of light from the vulnerable sealing area), sparks (high-temperature particles released due to the detachment of internal electrodes and the melting of the aluminum current collector), and high-temperature vent gas. In particular, these do not remain confined to the affected area but can spread to surrounding modules, including nearby battery cells, making it highly likely to lead to a major accident.

[0008] In conventional battery fire suppression techniques, directional venting of battery cells and the directionality of flames are generally ignored, and techniques that physically block sparks and flames with partitions are common. However, when solving battery fires through this method, changing only the blocking method without adjusting the placement of heat sources has reached its limits in addressing thermal propagation when energy density increases. [Overview of the project] [Problems that the invention aims to solve]

[0009] The present invention was devised to solve the above-mentioned problems, and aims to provide a battery module that can prevent battery fires, particularly explosive fires accompanied by spontaneous ignition.

[0010] Furthermore, another objective of the present invention is to provide a battery pack and ESS with enhanced safety by including the fire-prevention battery module described above. [Means for solving the problem]

[0011] 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 in a vertical direction with the housings facing each other, each battery cell having a housing portion in which an electrode assembly is housed, a first edge portion and a second edge portion along the longitudinal direction around the housing portion, and a third edge portion and a fourth edge portion along the width direction around the housing portion, wherein the battery cells include a resealing portion in the first edge portion, and the second edge portion includes a sealed portion or an unsealed portion, and the first edge portion and the second edge portion are alternately located on both sides of the cell stack along the vertical direction.

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

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

[0014] The first edges of approximately half of the battery cells may face one of the side plates, while the first edges of the remaining battery cells may face the other side plate.

[0015] A battery module according to another embodiment of the present invention further includes a module housing for housing the cell stack, the module housing including a pair of side plates located on both sides of the cell stack, and a top plate covering the top of the cell stack, wherein 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 for housing the cell stack, the module housing including a pair of side plates located on both sides of the cell stack, and a top plate covering the top of the cell stack, wherein 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 further includes a module housing that accommodates the cell stack, the module housing includes a pair of side plates located on both sides of the cell stack, and heat dissipation fins may be formed on the outside of the side plates.

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

[0019] A battery module according to an embodiment of the present invention may further include a buffer pad located on either the upper or lower side of the cell stack.

[0020] A battery module according to an embodiment of the present invention may further include insulating plates located on either the upper or lower side of the cell stack.

[0021] The module housing further includes a base plate that supports the cell stack and a top plate that covers the upper part of the cell stack, wherein the base plate may be a U-frame structure capable of wrapping and securing the lower end of the side plate from the outside.

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

[0023] A battery module according to an embodiment of the present invention further includes a module housing for housing 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 the top of the cell stack, the module housing has a module opening in the longitudinal direction, and the module housing may further include a busbar frame assembly covering the module opening.

[0024] In embodiments of the present invention, the pair of side plates may include a pair of spark direction switching portions formed by bending one of their longitudinal ends toward the cell stack.

[0025] Here, the module housing may further include a fastening frame that connects between the pair of spark direction switching portions and has a hollow center portion.

[0026] Further, the battery cell includes electrode leads at the third edge portion and the fourth edge portion, the module housing further includes a top plate that covers the upper portion of the cell laminate, the module housing has a module opening formed in the longitudinal direction, the module housing further includes a bus bar frame assembly that covers the module opening, and the bus bar frame assembly can be in close contact with the spark direction switching portion and the fastening frame.

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

[0028] Still another aspect of the present invention provides an ESS including the battery module and the battery pack as described above. [[ID=,13]]

Effects of the Invention

[0029] According to one aspect of the present invention, when stacking battery cells for manufacturing a battery module, a battery pack, etc., the resealing portions are stacked in a zigzag manner so that the resealing portions are not biased in only one direction. The zigzag stacking arranges the sealing portions on both side surfaces of the cell laminate, that is, in both directions. While the relatively fragile resealing portion is opened, two-directional venting or heat energy dispersion becomes possible. Through this, a large amount of sparks and the high-temperature and high-pressure flare ejected by the thermal runaway of the battery cells are dispersed to reduce the pressure, and by setting the outer wall of the battery module and the battery pack to 500 °C or lower, spontaneous ignition and explosion generated by the contact of the hydrogen and oxygen of the surrounding vent gas can be blocked.

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

[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 generated during thermal runaway of battery cells, thereby preventing the occurrence of a fire, or preventing flames from spreading to nearby battery modules.

[0032] The following drawings accompanying this specification illustrate preferred embodiments of the invention and, together with the detailed description of the invention, serve to further illustrate the technical idea of ​​the invention; therefore, the invention should not be construed as being limited solely to what is shown in the drawings. [Brief explanation of the drawing]

[0033] [Figure 1] This is a perspective view of a battery cell included in a battery module according to one embodiment of the present invention. [Figure 2] This figure illustrates a method for manufacturing a battery cell included in a battery module according to one embodiment of the present invention. [Figure 3] This is a cross-sectional view of a battery module according to one embodiment of the present invention. [Figure 4] Figure 3 is an exploded perspective view of the cell stack included in the battery module. [Figure 5] This is an exploded perspective view showing another example of a cell stack. [Figure 6] This is an exploded perspective view of a cell stack using a comparative example. [Figure 7] This figure shows a modified version of the battery module shown in Figure 3. [Figure 8] This figure shows another variation of the battery module shown in Figure 3. [Figure 9] This figure shows yet another variation of the battery module shown in Figure 3. [Figure 10] This figure shows yet another variation of the battery module shown in Figure 3. [Figure 11] This is a perspective view of a battery module according to another embodiment of the present invention. [Figure 12] Figure 11 is an exploded perspective view of the battery module. [Figure 13] Figure 11 is an exploded perspective view of the cell stack included in the battery module. [Figure 14] Figure 11 is an exploded perspective view of some of the components located at the rear of the battery module. [Figure 15] Figure 11 is an exploded perspective view of some of the components located in front of the battery module. [Figure 16] Figure 11 is a partial cutaway view of the battery module. [Figure 17] This is a cross-sectional view of the battery module in Figure 11, parallel to its longitudinal direction. [Figure 18] This is a schematic diagram of a battery pack including a battery module according to one embodiment of the present invention. [Figure 19] This is a schematic diagram of an ESS including a battery module according to one embodiment of the present invention. [Modes for carrying out the invention]

[0034] Preferred embodiments of the present invention will be described in detail below with reference to the attached drawings. Prior to this, terms and words used in this specification and in the claims shall not be interpreted in their usual and dictionary sense, but in accordance with the principle that inventors can appropriately define the concepts of terms in order to best describe their invention, and shall be interpreted in a sense and concept that corresponds to the technical idea of ​​the present invention.

[0035] Therefore, the embodiments and configurations shown in the drawings described herein represent only one of the most preferred embodiments of the present invention and do not represent the entire technical concept of the invention. It should be understood that there are various equivalents and modifications that can be substituted for these at the time of filing this application.

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

[0037] Referring to Figure 1, the battery cell 10 includes a pouch outer casing 20 and an electrode assembly (not shown), with a pair of electrode leads 30 protruding from the outside of the pouch outer casing 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-like positive electrode and a negative electrode and the assembly is wound up; a stack type assembly in which rectangular positive and negative electrodes are stacked with a separator in between; a stack-folding type assembly in which unit cells are wound up by a long separation film; or a lamination-stack type assembly in which battery cells are stacked with a separator in between and adhere to each other.

[0039] Furthermore, it goes without saying that the electrolyte may be replaced not only with a commonly used liquid electrolyte, but also with a solid electrolyte, or a quasi-solid electrolyte in a gel state that is intermediate between liquid and solid, obtained by adding additives to a solid electrolyte.

[0040] The electrode assembly described above is housed in a pouch outer material 20, which typically has a laminate sheet structure consisting of an inner layer, a metal layer, and an outer layer. The inner layer, which is in direct contact with the electrode assembly, must have insulating and electrolyte-resistant properties, and furthermore, for sealing with the outside, it must have sealing properties, that is, the sealed portion where the inner layers are heat-bonded together must have excellent heat bonding strength. As the material for such an inner layer, polyolefin resins such as polypropylene, polyethylene, polyethylene acrylic acid, and polybutylene, polyurethane resins, and polyimide resins can be selected, but are not limited to these, and polypropylene, which has excellent mechanical properties such as tensile strength, rigidity, surface strength, and impact strength, as well as excellent chemical resistance, is most preferred.

[0041] The metal layer in contact with the inner layer acts as a barrier layer that prevents moisture and various gases from penetrating into the battery from the outside. A lightweight and easily moldable thin film of aluminum can be used as a preferred material for such a metal layer.

[0042] Furthermore, an outer layer is provided on the other side of the metal layer. Such an outer layer may be made of a heat-resistant polymer with excellent tensile strength, moisture resistance, and air resistance, so as to protect the electrode assembly while ensuring heat resistance and chemical resistance. Examples include nylon or polyethylene terephthalate, but it is not limited to these.

[0043] On the other hand, the pair of electrode leads 30 consist of a positive electrode lead and a negative electrode lead, and after the positive electrode tab and negative electrode tab of the electrode assembly are electrically connected, they may be exposed to the outside of the pouch outer material 20, or the tabs may be omitted and they may be directly connected to the electrode assembly.

[0044] The battery cell 10 may have a housing R in which the 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). Thus, the battery cell 10 may have four edge portions E1 to E4. In this embodiment, the electrode leads 30 are included in the third edge portion E3 and the fourth edge portion E4. In the pouch outer material 20, the distance between the two ends from which the electrode leads 30 protrude can be defined as the longitudinal direction of the battery cell 10. Thus, the electrode leads 30 may be provided at both ends in the longitudinal direction of the battery cell 10, i.e., at the front and rear ends of the battery cell 10.

[0045] The first edge portion E1 includes a resealing portion 50. The third edge portion E3 and the fourth edge portion E4 include a sealing portion 40. In the case of a four-sided sealing method, the second edge portion E2 also includes a sealing 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 means the part of the pouch outer material that has been folded. The drawing illustrates a four-sided sealing method. Therefore, the first edge portion E1 includes a resealing portion 50, and the second edge portion E2, the third edge portion E3, and the fourth edge portion E4 include a sealing portion 40.

[0046] The sealing portion 40 is the part to which the pouch outer material 20 is joined and seals the periphery of the housing portion R. The resealing portion 50 refers to the sealing portion that is created during the resealing operation performed after the degassing process of the battery cell 10.

[0047] When constructing battery modules or battery packs using battery cells, the capacity of the secondary battery can be increased by either minimizing the size of the battery module to reduce the space occupied by the battery cells within the device and increase space utilization, or by minimizing the area occupied by the sealing portion relative to a certain battery module size and increasing the size of the electrode assembly with the resulting surplus. For the latter reason, dimensions are almost always controlled by folding the sealing portion located on the side of the battery cell to form a folding portion. In the figure, the resealing portion 50 of the first edge portion E1 and the sealing portion 40 of the second edge portion E2 are folded. However, simply folding them may cause them to unfold due to the springback cell swelling phenomenon of the folding portion itself, so the folding portion can be taped to prevent this. Reference numeral 60 denotes the taping member.

[0048] Multiple battery cells 10 can be stacked along the Z-axis to form a battery module. Because the battery cells 10 have a flat shape along the XY plane, they are very advantageous for dense stacking along the Z-axis.

[0049] Figure 2 is a diagram illustrating a method for manufacturing a battery cell included in a battery module according to one embodiment of the present invention.

[0050] The battery cell 10 is manufactured through processes such as assembling a secondary battery and activating the secondary battery.

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

[0052] After housing the electrode assembly in the housing section R of the lower casing, the periphery of the housing section R of the lower casing and the corresponding periphery of the upper casing are brought into close contact, a portion of the contact is heat-fused, then the electrolyte is injected, and the remaining portion is vacuum-sealed to assemble the secondary battery. The housing section R can also be formed in the upper casing. With the four-sided sealing method, all four edge sections E1 to E4 essentially become the sealed section 40.

[0053] In the activation process, to ensure smooth current flow, the secondary battery is mounted on a predetermined jig, and charging and discharging are performed under the conditions necessary for activation. Due to the characteristics of secondary batteries, such an activation process must always precede the activation of the positive electrode active material during the first cycle and the formation of a stable surface film (SEI: Solid Electrolyte Interface) on the negative electrode. A large amount of gas is generated inside the secondary battery during the activation process. Subsequently, the generated gas is removed through an opened or cut-out outlet, and the gas outlet is resealed by heat fusion. The process of releasing the gas from inside the secondary battery and heat-sealing the outlet passage is usually called the degassing process. The part that is resealed by heat fusion is the resealed part 50. In this embodiment, the resealed part 50 is included in the first edge part E1. The excess pouch outer material 20 outside the resealed part 50 is cut and removed.

[0054] The inventors have found that the resealed portion 50 of the first edge portion E1, being formed by resealing after a degassing process, has lower sealing strength during thermal runaway than the sealing portion 40 of the second edge portion E2 on the opposite side, and tends to rupture first. They have also found that when multiple battery cells 10 are housed in a module housing, if such resealed portions 50 are concentrated on one side, an aluminum module housing may melt. Furthermore, they have found that when multiple battery cells 10 are housed in a module housing, if the resealed portions 50 are concentrated on one side, even if a steel module housing does not melt, the temperature of the outer wall can reach over 800°C. At this time, if the hydrogen contained in the vent gas flowing around it exceeds 505°C, it is highly likely to mix with oxygen and cause an explosion. This is spontaneous combustion. The inventors focused on the fact that spontaneous combustion of the battery module can be prevented by controlling the temperature of the module housing by adjusting the arrangement of the resealed portions 50, and thus completed the present invention.

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

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

[0057] Multiple battery cells 10 are stacked vertically (in 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 called the vertical direction or the Z-axis direction. In embodiments of the present invention, the battery cells 10 are stacked so that the resealing portions 50 of all the battery cells 10 do not face either one side. For example, within the cell stack 110, the resealing portions 50 are arranged in both directions in the width direction. For example, along the Z-axis direction, one resealing portion 50 is located on the left side and the other resealing portion 50 is located on the right side, in a zigzag pattern. As a result, on both sides of the cell stack 110, a first edge portion E1 including the resealing portion 50 and a second edge portion E2 not including the resealing portion 50 are alternately located along the vertical direction. The second edge portion E2 includes the sealed portion 40 or the unsealed portion as described above.

[0058] In this case, as shown in Figure 4, one first edge portion E1 including the resealing portion 50 and one second edge portion E2 not including the resealing portion 50 may be alternately positioned along the vertical direction on both sides of the cell laminate 110, or multiple first edge portions E1 including the resealing portion 50 and multiple second edge portions E2 not including the resealing portion 50 may be alternately positioned, as shown in Figure 5. For example, as shown in Figure 5, two or more may be alternately positioned.

[0059] In any case, preferably, the resealing portions 50 are distributed approximately half each (placed on both sides in the width direction) between the left and right walls of the module housing 120, and multiple battery cells 10 are stacked alternately. Through this, the pressure and temperature concentrated on both side walls of the module housing 120 within the cell stack 110 can be significantly reduced. For example, if the number of battery cells 10 is 2n, n battery cells 10 have their resealing portions 50 on the left wall side, and the remaining n battery cells 10 have their resealing portions 50 on the right wall side. If the number of battery cells 10 is 2n+1, n or n+1 battery cells 10 have their resealing portions 50 on the left wall side, and the remaining n+1 or n battery cells 10 have their resealing portions 50 on the right wall side.

[0060] Even when the first edge portion E1 and the second edge portion E2 are stacked alternately along the vertical direction in this manner, the electrode leads 30 can be stacked in a single vertical line along the front and rear of the cell stack 110, as the third edge portions E3 are aligned with each other, the fourth edge portions E4 with each other, or the third edge portion E3 and the fourth edge portion E4 are aligned vertically from the front and rear. It can be understood that the polarity of the electrode leads 30 located at the front is all the same, or that opposite polarities are located along the vertical direction. Furthermore, considering the polarity of the electrode leads 30 and the arrangement of the resealing portion 50, it can be seen that some of the battery cells 10 can be stacked upside down.

[0061] The module housing 120 shown in Figure 3 has an internal space capable of housing the battery cells 10, provides mechanical support for the housed battery cells 10, and protects them from external impacts. Referring further to Figure 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 covering the top of the cell stack 110, and a base plate 150 supporting the cell stack 110.

[0062] The side plates 130 and the cell laminate 110 can be separated to form a space S. Such a space S can be configured to contain the flares and sparks ejected during swelling. For example, a pair of side plates 130 can be separated from each other at a distance slightly wider than the width W of the cell laminate 110 to form a space S.

[0063] Furthermore, the battery module 100 may further include a PC sheet 160 and a mica sheet 170. The PC sheet 160 and mica sheet 170 may be located between the module housing 120 and the side surface of the cell stack 110. In particular, in this embodiment, they are located between the side plate 130 and the side surface of the cell stack 110. The PC sheet 160 and mica sheet 170 may be located on both sides 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 mica sheet 170 are flexible or easily deformable so as to block the propagation of flames and heat from flames to other battery cells 10 or the side plate 130 when a flame occurs in one of the battery cells 10.

[0064] Approximately half of the first edge portions E1 of the multiple battery cells 10 contained in the cell stack 110 face the left side plate 130a, which is one of the side plates 130, and the remaining first edge portions E1 of the multiple 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 portion 50 within the cell stack 110, the pressure and temperature concentrated on both side plates (130a, 130b) can be distributed evenly to both sides, and the temperature of the side plate facing the resealing portion 50 can be significantly reduced compared to when it is concentrated on one side.

[0065] Figure 6 shows a comparative example, a cell stack 110' in which the resealing sections 50 are arranged in only one direction, for example, only on the left side. In such a cell stack 110', all eight resealing sections 50 face one side wall of the module housing, forming a battery module. When the resealing sections 50 are biased to one side in this way, they may be exposed to high temperature and pressure in a short time, potentially leading to a gas explosion. This is because when the fragile resealing sections 50 are concentrated on one side, the temperature rise is maximized, causing spontaneous combustion that leads to explosion upon contact with flammable and explosive vent gas.

[0066] Since the resealed portion 50 is formed by resealing after the degassing process, it is more fragile than the sealed portion 40 or unsealed portion on the opposite side, and therefore may be the first to rupture in the event of thermal runaway. If such resealed portions 50 are concentrated on one side, as in the comparative example, an aluminum module housing will melt, and even if a steel module housing does not melt, the temperature of the outer wall will rise to over 800°C. If the hydrogen contained in the vent gas flowing around it exceeds 505°C, spontaneous combustion will occur, causing it to mix with oxygen and explode. Therefore, the battery module including the cell stack 110' of the comparative example is vulnerable to fire.

[0067] On the other hand, in the cell stack 110 included in the battery module 100 according to one embodiment of the present invention, the arrangement of the resealing parts 50 is adjusted to prevent spontaneous combustion. In the present invention, when stacking battery cells 10 to manufacture the battery module 100 and the battery pack including the battery module 100, that is, when manufacturing the cell stack 110, the resealing parts 50 are stacked in a zigzag pattern so that the resealing parts 50 are not concentrated on one side. Zigzag stacking arranges the resealing parts 50 in parallel directions facing each other. The resealing parts 50 located in both directions open before the sealed parts 40 or unsealed parts, and because the resealing parts 50 are arranged in both directions, bidirectional directional venting can be achieved. Furthermore, thermal energy can be dispersed in both directions. Through this, a large amount of sparks and high-temperature, high-pressure flares ejected from the thermal runaway of the battery cells 10 are dispersed, reducing the pressure and lowering the temperature of the outer wall of the module housing 120 to below 500°C. Therefore, it is possible to prevent spontaneous combustion and explosions that occur when hydrogen and oxygen in the surrounding vent gas come into contact.

[0068] On the other hand, Figure 3 shows that the base plate 150, top plate 140, and pair of side plates 130 are manufactured separately and then joined together. However, 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, top plate 140, and pair of side plates 130 may all contain the same material. Also, Figure 3 shows a simplified conceptual representation of the base plate 150, top plate 140, and pair of side plates 130. The effect of the distributed arrangement of the resealing sections 50 can be maximized by combining it with various embodiments of the module housing 120 described later.

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

[0070] Due to the structure of the cell stack 110, the vent gas discharged from the resealing section 50 first collides with the side plate 130. The change in the heat quantity of the side plate 130 due to the vent gas is Qin (amount of heat entering the side plate 130) - Qout (amount of heat leaving the side plate 130), which can be said to be equivalent to Cp × M × 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 changed temperature. When Qin - Qout is constant, increasing M can reduce ΔT. In other words, increasing the thickness d2 of the side plate 130 makes it possible to increase M and reduce the temperature change. However, making the thickness d2 of the side plate 130 excessively thick is undesirable as it leads to an increase in material costs and an increase in the overall weight of the battery module 100. The thickness d2 of the side plate 130 should be increased within an appropriate budget. For example, if the currently used module housing 120 has a thickness of 1.6 mm, the thickness d2 of the side plate 130 can be made thicker, such as 1.8 mm. Alternatively, to maintain overall material costs and weight, the top plate 140 may be constructed with a reduced thickness d1 to compensate for the increased thickness d2 of the side plate 130. Thus, in the battery module 100 shown in Figure 7, the thickness d2 of the side plate 130 is even thicker than the thickness d1 of the top plate 140. For example, the thickness d1 of the top plate 140 is 1.6 mm, and the thickness d2 of the side plate 130 is made thicker, at 1.8 mm.

[0071] The thickness d1 of the top plate 140 and the thickness d2 of the side plate 130 can be determined by considering various conditions such as material cost, weight, fire prevention, and durability. If the top plate 140 and the side plate 130 are made of the same material, the determination can also take into account factors such as thermal stress and thermal deformation caused by the difference in thickness. For example, the thickness d2 of the side plate 130 can be determined to be 5% to 50% thicker than the thickness d1 of the top plate 140.

[0072] By increasing the thickness d2 of the side plate 130 and thereby increasing the M of the side plate 130, the temperature of the side plate 130 can be controlled to remain below 500°C even when vent gas is discharged through the resealing section 50. Therefore, spontaneous combustion caused by contact between hydrogen and oxygen in the surrounding vent gas can be effectively prevented.

[0073] Figure 8 shows another modification of the battery module 100 shown in Figure 3, which includes an improved module housing 120. In this embodiment, the side plate 130 contains a material with a higher specific heat than the top plate 140. That is, the material of the top plate 140 and the material of the side plate 130 are different, and the specific heat of the side plate 130 is even higher.

[0074] As described above, due to the structure of the cell laminate 110, the vent gas discharged from the resealing section 50 first collides with the side plate 130. In the change in the heat quantity of the side plate 130 due to the vent gas, "Qin-Qout = Cp × M × ΔT", if Qin-Qout is constant, ΔT can be reduced even if Cp is increased. In other words, it is possible to reduce temperature changes by increasing the specific heat of the side plate 130. However, excessively increasing the specific heat of the side plate 130 is undesirable due to increased material costs and the difficulty of selecting an appropriate material. The specific heat of the side plate 130 should be increased within an appropriate 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 to increase specific heat increases, the specific heat of the top plate 140 may be reduced to compensate for the increased specific heat of the side plate 130 in order to maintain overall material costs. Thus, in the battery module 100 shown in Figure 8, the specific heat of the side plate 130 is configured to be even higher than that of the top plate 140. For example, the specific heat of the side plate 130 can be increased by using galvanized steel for the top plate 140 and further incorporating metals such as aluminum, titanium, magnesium, and silicon, which have higher specific heats than zinc and iron, in the form of alloys or plating for the side plate 130.

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

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

[0078] As repeatedly mentioned above, due to the structure of the cell laminate 110, the vent gas discharged from the resealing section 50 first collides with the side plate 130. In this embodiment, by including heat dissipation fins 135 in the side plate 130, heat can be dissipated to the outside without accumulating on the side plate 130. The heat dissipation fins 135 are configured to maximize the surface area for effective heat dissipation. Through this, even if vent gas is discharged through the resealing section 50, the temperature of the side plate 130 can be controlled to 500°C or less, effectively preventing spontaneous combustion.

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

[0080] Here, the thermal spreader 180 refers to an object that absorbs and dissipates heat from other objects through direct thermal contact. The thermal spreader 180 has materials and a structure specialized for heat conduction and radiation, and can take heat from the heat-generating battery cell 10 and release it to the surroundings. For example, the thermal spreader 180 may be attached to the inside of the side plate 130 and be a component that diffuses and dissipates the heat generated in the battery cell 10. The thermal spreader 180 may contain silicon, acrylic, or graphite material.

[0081] In addition to the thermal spreader 180, the battery module 100 may further include a Thermal Interface Material (TIM) layer to enhance the heat transfer performance between different components. The TIM layer is intended to reduce the contact thermal resistance between components. Such a TIM layer may contain a variety of thermally conductive materials such as metals, polymers, or ceramics, 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 thermal resin.

[0082] By including the thermal spreader 180, heat can be dissipated to the outside without accumulating on the side plate 130. According to this embodiment of the present invention, the heat dissipation performance of the battery cell 10 can be further improved. Through this, even if vent gas is discharged through the resealing section 50, the temperature of the side plate 130 can be controlled to 500°C or less, effectively preventing spontaneous combustion.

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

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

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

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

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

[0088] Multiple battery cells 10 can be stacked face to face. If the surface of the pouch outer material 20 is smooth, the multiple battery cells 10 are prone to slipping due to external impacts when stacked. Therefore, in order to prevent this and maintain a stable stacked structure of the battery cells 10, an adhesive member 70, such as double-sided tape or a chemical adhesive that bonds through a chemical reaction during bonding, can be attached to the surface of the pouch outer material 20 to form a cell stack 110.

[0089] The battery module 200 may further include a buffer pad 260 located on at least one side of the cell stack 110, either above or below.

[0090] At least one cushioning pad 260 is located on at least one of the top and bottom of the stacked battery cells 10 and may be interposed between the battery cells 10 as needed. Such a cushioning pad 260 is made of a material whose volume is easily changed by external pressing forces, and may be, for example, a sponge or a nonwoven fabric.

[0091] Furthermore, the cell laminate 110 may further include an insulating plate 270 located on at least one side, either above or below.

[0092] The insulating plate 270 is located on at least one of the top and bottom of the stacked battery cells 10, and of course on the outside of the cushioning pad 260 if one is attached, to uniformly press against the entire surface of the battery cells 10 and prevent current from flowing between the metal module housing 220 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] Similar to Figures 11 and 12, the module housing 220 comprises 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 surface of the cell stack 110, as described above.

[0095] The base plate 250 is a U-frame structure that can wrap around and secure 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 configuration can be implemented by various methods such as pressing or roll forming.

[0096] The top plate 240 and the side plates 230 can be connected to each other to form a U-frame structure. Alternatively, the top plate 240 and the side plates 230 can be constructed separately and assembled into a U-frame structure by welding, bonding, fitting, hook connection, or bolt connection. Alternatively, the top plate 240 and side plates 230 can be manufactured by bending both ends of a single plate, similar to the method used to manufacture 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 can be discharged through the module opening 200a. In this embodiment, the module openings 200a are formed at the front and rear ends in the longitudinal direction of the battery cell 10, respectively.

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

[0099] A pair of side plates 230 may have a spark direction switching portion 230a formed by bending one of its longitudinal ends toward the cell stack 110.

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

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

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

[0103] The module opening 200a provided in the module housing 220 according to an embodiment of the present invention may be formed entirely on both sides in the longitudinal direction of the module housing 220. In this case, the pair of spark direction switching sections 230a may also be provided entirely on one side and the other side in the longitudinal direction of the module housing 220.

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

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

[0106] The busbar frame 292 has a shape that corresponds 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 is equipped with a fastening frame 232 as described above, the busbar frame 292 is in close contact with the spark direction switching section 230a and the fastening frame 232.

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

[0108] The spark direction switching section 230a and the fastening frame 232 are deformable to contain flares and sparks. In this case, it is obvious that the busbar frame 292 can also be changed to accommodate the deformed outer shape.

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

[0110] Referring to Figures 11 to 17, the assembly process of the battery module 200, including the above-described configuration, is explained as follows: an insulating plate 270, a buffer pad 260, multiple battery cells 10, a buffer pad 260, and an insulating plate 270 are stacked in that 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 busbar 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. After that, the electrode leads 30 are passed through the busbar slits 294a of the busbar 294, then bent and fixed through known joining means such as welding.

[0111] The cell laminate 110 prepared in this manner is housed in a form that is covered by a base plate 250, a top plate 240, and a pair of side plates 230. At this time, the top plate 240 and the pair of side plates 230 are joined together to form a U-frame structure, and this U-frame covers both sides and the top surface of the cell laminate 110, resulting in a form in which the cell laminate 110 is housed while the front, rear and bottom surfaces are open.

[0112] The base plate 250 is joined to the U-frame so as to wrap around the lower end of the side plate 230 from the outside. The joining may be done by welding, but in this embodiment, examples of joining with tape 252 and bolts 254 are given.

[0113] The busbar frame 292 is placed in close contact with the spark direction switching section 230a and the fastening frame 232, and the busbar frame 292 serves to cover the module opening 200a of the module housing 220.

[0114] The paths of vent gas and sparks in the battery module 200 will be explained with particular reference to Figure 17.

[0115] Referring to Figure 17, the battery module 200 according to an embodiment of the present invention, as described above, is equipped with a spark direction switching section 230a to prevent high-temperature sparks discharged 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, when the battery cells 10 are vented, the high-temperature sparks ejected from both sides in the width direction of each battery cell 10 constituting the cell stack 110, i.e., from the alternately arranged resealing sections 50, move toward one end and / or the other end in the longitudinal direction of the battery module 200, and then their direction of movement is switched toward the cell stack 110 (see the direction of the dotted arrows shown in Figure 17). Furthermore, because the flare and sparks are confined in the space created by the spark direction switching section 230a, they cannot be released to the outside, and their movement in the direction in which the electrode leads 30 are located is also restricted, thereby blocking direct contact with the electrode leads 30. In this way, the spark direction switching section 230a realizes a spark pocket structure.

[0116] If thermal runaway occurs in a specific battery cell, flares, sparks, high-pressure vent gas, and hot air are ejected, and if these coexist with oxygen and flammable materials, it can lead to fire or explosion. The side plate 230 of the battery module 200 according to the embodiment of the present invention prevents thermal runaway products such as flares and sparks from being ejected to the outside of the module housing 220, and also discharges the vent gas and hot air through the module opening 200a, and in this process the air that was filling the inside of the module housing 220 is also discharged, so that flames cannot be generated.

[0117] In this invention, by stacking the resealing portions 50 of the battery cell 10 in a zigzag pattern, the resealing portions 50 are not biased in one direction, thereby dispersing a large amount of sparks and high-temperature, high-pressure flares ejected from thermal runaway of the cell, and reducing the pressure. This has the effect of preventing spontaneous combustion and explosion that occur when hydrogen and oxygen in the surrounding vent gas come into contact. Furthermore, for example, assuming that thermal runaway occurs in a specific battery cell 10 where the first edge portion E1 is located on the left side and the resealing portion 50 is located on the left side, as shown in Figures 16 and 17, the flares and sparks will be contained and collected in the space located on the left side, particularly the space surrounded by the left-side spark direction switching portion 230a. Therefore, they will not only not move forward or backward where the busbar 294 is located, but also not move to the right side of the battery cell 10. On the other hand, since the module housing 220 and the cell stack 110 do not maintain a perfect airtight state, the generated vent gas is discharged through the module opening portion 200a near the busbar frame 292.

[0118] As a result, even if a thermal event occurs in any one of the battery cells, the air is expelled to the outside along with the vent gas, so there is insufficient oxygen inside the module housing 220 for ignition, and the flammable material is trapped and not released to the outside of the module housing 220. Furthermore, when air is expelled, hot air is also expelled, keeping the temperature below the ignition point, thus preventing a fire from occurring.

[0119] By including the module housing 220 that realizes the spark pocket in this way, the fire safety of the battery module 200 is increased. Furthermore, by distributing the unique resealing portions 50 of the present invention, when the temperature of the module housing 220 is controlled to a temperature that does not cause spontaneous combustion, it is possible to prevent explosive ignition from occurring due to the internal transition conditions after thermal runaway occurs.

[0120] Furthermore, a battery pack including this can completely block flames. The battery modules 100 and 200 having the above configuration can be housed in a separate pack case or not, and can constitute a single battery pack. Moreover, the battery modules and battery packs can be used in various equipment and devices that include large-capacity power sources, such as ESS, electric vehicles, hybrid vehicles, and plug-in hybrid electric vehicles.

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

[0122] As shown in Figure 18, a battery pack 300 can be constructed by arranging multiple battery modules 100, 200 adjacent to each other along 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 along the width direction. The battery pack 300 may also include ducts 320 coupled to one or both sides in the longitudinal direction of the battery pack 300. The battery pack 300 may further include a pack case (not shown) that houses such 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 battery modules 100, 200 arranged adjacent to each other. Although not shown in detail, the BMS assembly 310 includes at least one BMS for controlling the 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 duct 320.

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

[0125] Recently attracting attention, ESS (Electrical Energy Storage) is a device that maximizes power usage efficiency by storing generated electricity in batteries and supplying it to consumers when needed. In an ESS, multiple battery modules constitute one rack, and dozens to hundreds of racks come together to form a single system. It can also be used in conjunction with UPS (Uninterruptible Power Supply) devices that enable stable power supply in response to sudden power supply interruptions or abnormalities, and solar power generation systems that convert sunlight into electrical energy. The battery modules 100 and 200 according to the embodiment of the present invention are particularly suitable as battery modules for ESS because they have excellent fire prevention effects.

[0126] Figure 19 is a schematic diagram of an ESS including a battery module according to one embodiment of the present invention. An ESS400 according to an embodiment of the present invention may include battery modules 100 and 200 according to an embodiment of the present invention. Furthermore, because the ESS400 has a large energy capacity, it may include multiple battery modules 100 and 200 according to one embodiment of the present invention in a configuration that is electrically connected to one another. In addition, an ESS400 according to one embodiment of the present invention may further include a variety of other components of ESS known at the time of filing of the present invention. Furthermore, such an ESS400 can be used in a variety of locations and devices, such as smart grid systems and electric charging stations. In particular, an ESS400 according to one embodiment of the present invention may be a residential (building) ESS for home or office use, used for storing energy in homes, office buildings, and other buildings.

[0127] On the other hand, while terms such as up, down, left, right, front, and back are used in this specification to indicate direction, these terms are used for convenience of explanation, and it is obvious to those skilled in the art that they can change depending on the position of the object being examined, the position of the observer, etc.

[0128] Although the present invention has been described above with reference to limited embodiments and drawings, it goes without saying that the present invention is not limited thereto, and that various modifications and variations can be made by persons with ordinary skill in the art to which the present invention belongs, within the equivalent scope of the technical concept and claims of the present invention. [Explanation of Symbols]

[0129] 10: Battery cell 40: Sealing part 50:Resealing part 100, 200: Battery Module 110: Cell laminate 120, 220: Module housing 130, 230: Side plate 135: Heat dissipation fins 140, 240: Top plate 150, 250: Base plate 160: PC Sheet 170: Mica Sheet 180: Thermal spreader 230a: Spark direction switching section 232: Fastening Frame 260: Cushioning pad 270: Insulating plate 290: Busbar Frame Assembly 292: Busbar Frame 294: Bus bar 300: Battery Pack 400:ESS

Claims

1. The invention includes a cell stack formed by stacking a plurality of pouch-type battery cells, each having a housing portion containing an electrode assembly, a first edge portion and a second edge portion along the longitudinal direction around the housing portion, and a third edge portion and a fourth edge portion connecting the first edge portion and the second edge portion around the housing portion, with the housing portions facing each other in the vertical direction. The battery cell includes a resealed portion at the first edge and a sealed portion or an unsealed portion at the second edge. The first edge portion and the second edge portion are alternately positioned on both sides of the cell laminate along the vertical direction. The aforementioned longitudinal direction is the direction in which the electrode leads of the battery cell protrude. The sealing portion is the part to which the pouch outer material is joined and seals the periphery of the housing portion. The resealed portion is a portion that has been resealed after being opened or cut, and has a lower seal strength than the sealed portion. The unsealed portion is the portion of the pouch outer material that has been folded, which is the battery module.

2. The module housing further includes a module housing that accommodates the cell stack, 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 the top of the cell stack, the thickness of the side plates being greater than the thickness of the top plate.

3. The module housing further includes a module housing that accommodates the cell stack, 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 the top of the cell stack, and the side plates are made of a material having a higher specific heat than the top plate.

4. The module housing further includes a module housing that accommodates 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 heat dissipation fins are formed on the outside of the side plate.

5. The module housing further includes a module housing that accommodates 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 separated to form a space.

6. The battery module according to claim 5, further comprising a polycarbonate sheet and a mica sheet between the module housing and the side surface of the cell stack.

7. The battery module according to any one of claims 2 to 5, wherein the first edges of approximately half of the battery cells among the plurality of battery cells face one of the side plates, and the first edges of the remaining battery cells among the plurality of battery cells face the other of the side plates.

8. The battery module according to claim 5, further comprising a thermal spreader between the module housing and the side surface of the cell stack.

9. The battery module according to any one of claims 1 to 5, further comprising a buffer pad located on either the upper or lower side of the cell stack.

10. The battery module according to any one of claims 1 to 5, further comprising an insulating plate located on either the upper or 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 the upper part of the cell stack. The battery module according to any one of claims 2 to 5, wherein the base plate has a U-frame structure that can wrap around and secure the lower end of the side plate from the 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 accommodates the cell stack, The module housing includes a pair of side plates located on both sides of the cell stack, and a top plate that covers the top 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 includes a busbar frame assembly covering the module opening.

14. The battery module according to any one of claims 2 to 5, wherein the pair of side plates are provided with a pair of spark direction switching portions formed by bending one of their longitudinal ends toward the cell stack.

15. The battery module according to claim 14, further comprising a fastening frame that connects a pair of spark direction switching sections and has a central opening therebetween.

16. The battery module according to claim 15, wherein the battery cell includes electrode leads on the third and fourth edges, the module housing further includes a top plate covering the upper part of the cell stack, the module housing has a module opening formed in the longitudinal direction, the module housing further includes a busbar frame assembly covering the module opening, and the busbar frame assembly is in close contact with the spark direction switching section and the fastening frame.

17. The battery module according to any one of claims 1 to 5, wherein the resealed portion has lower sealing strength during thermal runaway than the sealed portion or the unsealed portion.

18. A battery pack comprising a battery module according to any one of claims 1 to 5.

19. An energy storage system comprising a battery module according to any one of claims 1 to 5.

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