Battery systems and vehicles containing them

Abstract

A battery system and a vehicle including the same are introduced, which include a battery module, a pack case in which the battery module is installed, and a biasing unit installed between the pack case and the battery module, which pressurizes the battery module relative to the pack case and has its end supported by the pack case or the battery module through a cap made of fire-resistant material.

Description

Technical Field

[0001] The present invention relates to a battery system with improved safety in abnormal battery situations and a vehicle including the same.

Background Art

[0002] Recently, technologies for carbon reduction have been actively developed to solve environmental problems such as abnormal temperatures. To reduce carbon, energy must be produced in an environmentally friendly way rather than by producing energy from fossil fuels, store the produced energy in the form of electrical energy, and use the stored electrical energy in vehicles, various industrial sites, and homes.

[0003] To utilize electrical energy for carbon reduction, it is essential to use a battery that can store and draw out electrical energy. Therefore, ensuring the performance of the battery is essential to sufficiently store electrical energy and use it without inconvenience.

[0004] Batteries mainly utilize the oxidation-reduction reaction of metal ions, use metal ions at high density to increase the capacity, charge-discharge performance, and efficiency of the battery, and much research has been done on substances constituting electrolytes and solid electrolytes. However, generally, there is a problem that the stability of the battery decreases as its performance develops.

[0005] In the case of batteries used in vehicles, industries, homes, etc., they are manufactured in a physical unit called a pack. The battery pack incorporates a large number of battery cells inside a battery case and seals them to prevent the transfer of fire to the outside even in case of an accident such as thermal runaway of the battery, and to protect the internal battery cells from deterioration due to the influence of the external environment or damage for physical reasons.

[0006] A battery pack contains numerous battery cells in an intermediate form called a module. In the case of a battery module, many battery cells are assembled into a single module, and many modules are fastened together inside the pack case, completing the battery pack. During battery maintenance, maintenance is performed at the module level to facilitate maintenance.

[0007] The numerous unit battery cells that make up a battery module consist of a positive electrode, a negative electrode, and an electrolyte. Since battery cells generate heat during charging and discharging, effective heat dissipation is necessary. Furthermore, from the perspective of the battery module and battery pack, efficient heat dissipation design is essential to prevent safety accidents.

[0008] On the other hand, batteries can deteriorate due to manufacturing errors, excessive charging and discharging, and aging. If battery deterioration continues, it can eventually lead to a fire. Therefore, it is necessary to take precautions to prevent fires from occurring due to batteries. To this end, it is important to continuously sense the battery's condition and to recognize and respond to any problems in advance, so that damage can be minimized in the event of an unexpected problem.

[0009] In particular, if a flame occurs in a specific cell of a specific module among the many battery modules inside a battery pack, the spread of the flame to other adjacent battery cells must be prevented, as must the spread of the flame to other adjacent modules. Therefore, from the perspective of the battery module, gas venting from the problematic battery cell must be smooth, while at the same time, the vented gas or flame must be prevented or delayed as much as possible from affecting other cells or modules.

[0010] The matters described above as background technology are for the sole purpose of enhancing understanding of the background of the present invention and should not be taken as constituting prior art already known to those with ordinary skill in this art. [Overview of the Initiative] [Problems that the invention aims to solve]

[0011] This invention was proposed to solve these problems and aims to provide a battery system and a vehicle including it that can improve battery safety by preventing fire propagation to adjacent cells or modules in the event of a fire in a specific battery cell or battery module, while still allowing for smooth gas venting.

[0012] The technical problems that this invention aims to solve are not limited to those mentioned above, and other technical problems not mentioned will be clearly understood by those with ordinary skill in the art to which this invention pertains from the description below. [Means for solving the problem]

[0013] A battery system according to the present invention for achieving the above objectives includes a battery module, a pack case in which the battery module is installed, and a biasing unit installed between the pack case and the battery module, which pressurizes the battery module relative to the pack case, and whose end is supported by the pack case or the battery module through a cap made of fire-resistant material.

[0014] In the battery system according to the present invention, a venting portion is formed on the outer surface of the battery module facing the pack case, and the biasing portion may be positioned at a location that avoids the venting portion.

[0015] In the battery system according to the present invention, the biasing portion consists of a first cap, a second cap, and a biasing body, and the biasing body may be located between the first cap and the second cap.

[0016] In the battery system according to the present invention, the first cap of the biasing portion can be in close contact with the inner surface of the pack case, and the second cap can be in close contact with the outer surface of the battery module.

[0017] In the battery system according to the present invention, the first or second cap of the biasing portion is attached to the inner surface of the pack case or the outer surface of the battery module with an adhesive, and the adhesive may be made of a heat-resistant material.

[0018] In the battery system according to the present invention, the first cap of the biasing portion is fixed in a state where it is inserted into the second cap, and the biasing body can maintain a compressed state between the first cap and the second cap.

[0019] In the battery system according to the present invention, the first cap of the biasing section is pulled out from the second cap by gas or flame generated from the battery module, and the biasing body can be extended by the pulling out of the first cap.

[0020] In the battery system according to the present invention, the first cap of the biasing part is pulled out from behind the second cap due to the rise in temperature inside the pack case, and the biasing body can be extended by the pulling out of the first cap.

[0021] In the battery system according to the present invention, the first cap of the biasing portion is locked and fixed in a state where it is inserted into the second cap, and the first cap can be separated from the second cap when the second cap expands due to high temperature.

[0022] In the battery system according to the present invention, the first cap of the biasing portion is fixed by adhesive while inserted into the second cap, and the first cap can be separated from the second cap when the adhesive strength is lost due to high temperature.

[0023] In the case of the battery system according to the present invention, a plurality of biasing portions are provided between the pack case and the battery module, and the biasing force of the biasing portion can increase as it gets closer to the central side of the pack case.

[0024] In the case of the battery system according to the present invention, the biasing portion closer to the central side of the pack case may have a greater elastic coefficient or compression amount than the biasing portion away from the central side of the pack case.

[0025] In the case of the battery system according to the present invention, a module cover is coupled to the battery module to cover one side surface of the battery module, and the biasing portion may be provided between the pack case and the module cover.

[0026] In the case of the battery system according to the present invention, the biasing portion is disposed at a point between the pack case and the module cover and may be fixed to the module cover.

[0027] In the case of the battery system according to the present invention, one end of the biasing portion may be fixed to the module cover and the other end may be spaced apart from the pack case.

[0028] In the case of the battery system according to the present invention, the biasing portion is extended by gas or flame inside the pack case, or by high temperature. When the biasing portion is extended, both ends of the biasing portion may be supported by the pack case and the module cover, respectively.

[0029] In the case of the battery system according to the present invention, the pack case includes a case body with one side open and a pack lid for closing the case body, and the biasing portion may be located between the pack lid and the battery module.

[0030] In the battery system according to the present invention, when gas or flames or high temperatures are generated inside the pack case, the pack leads expand, increasing the distance between the pack leads and the battery module. The biasing portion stretches as the distance between the pack leads and the battery module increases, allowing the battery module to be pressurized relative to the pack leads.

[0031] In the case of a vehicle according to the present invention, the battery system is as described above. [Effects of the Invention]

[0032] The battery system and vehicle incorporating the present invention can prevent the spread of fire to adjacent cells or modules in the event of a fire in a specific battery cell or battery module, and at the same time, it can improve the safety of the battery system and the higher-level systems that utilize it by facilitating gas venting in the problematic battery cell or battery module.

[0033] The effects obtained by the present invention are not limited to those mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art to which the present invention pertains from the description below. [Brief explanation of the drawing]

[0034] [Figure 1] This figure shows a battery system according to one embodiment of the present invention. [Figure 2] This figure shows the biasing section of the battery system illustrated in Figure 1. [Figure 3] This is a cross-sectional view showing the case where the biasing unit is provided above the battery system of the present invention. [Figure 4] This is a cross-sectional view showing the case where the biasing portion is provided on the side of the battery system of the present invention. [Figure 5] This figure shows the biasing portion shown in Figure 2 in an extended state. [Figure 6]This figure shows the biasing portion shown in Figure 3 in an extended state. [Figure 7] This figure shows the biasing portion shown in Figure 4 in an extended state. [Figure 8] This figure shows various embodiments of the biasing mechanism of the present invention. [Figure 9] This figure shows various embodiments of the biasing mechanism of the present invention. [Figure 10] This figure shows various embodiments of the biasing mechanism of the present invention. [Figure 11] This figure illustrates the differences in location-specific biasing units in a battery system according to one embodiment of the present invention. [Figure 12] This figure shows a battery pack and a vehicle to which the battery system of the present invention is applied. [Modes for carrying out the invention]

[0035] In describing the embodiments disclosed herein, if a specific description of related published technology is deemed to obscure the gist of the embodiments disclosed herein, such detailed description will be omitted. Furthermore, the accompanying drawings are merely for the purpose of facilitating the understanding of the embodiments disclosed herein, and it should be understood that the accompanying drawings do not limit the technical ideas disclosed herein and include all modifications, equivalents, or substitutions that fall within the concept and technical scope of the present invention.

[0036] Terms including ordinal numbers, such as "first," "second," etc., can be used to describe a variety of components, but the components are not limited by such terms. These terms are used solely for the purpose of distinguishing one component from others. A singular expression includes plural expressions unless the context clearly indicates otherwise.

[0037] In this specification, terms such as “includes” or “having” are intended to indicate the presence of features, figures, stages, operations, components, parts, or combinations thereof described in the specification, and should not be understood to preemptively exclude the presence or possibility of adding one or more other features, figures, stages, operations, components, parts, or combinations thereof. The suffixes “module” and “part” used for components in the following description are added or used interchangeably solely for the sake of ease of specification preparation and do not have any distinct meaning or role in themselves.

[0038] When it is mentioned that one component is "connected" or "linked" to another component, it should be understood that it may be directly connected to or linked to the other component, but that other components may also exist in between. Conversely, when it is mentioned that one component is "directly connected" or "directly linked" to another component, it must be understood that there are no other components in between.

[0039] The embodiments disclosed herein will now be described in detail with reference to the attached drawings. Regardless of the reference numerals used in the drawings, identical or similar components will be given the same reference numerals, and redundant descriptions thereof will be omitted.

[0040] As shown in Figure 1, the battery system consists of multiple battery cells that come together to form a battery module 300, and multiple battery modules 300 come together to form a battery pack. The battery module 300 referred to in this invention means an assembly of multiple battery cells, and includes not only cases where multiple battery cells are stacked and housed inside a sealed separate housing, but also a variety of cases in which many battery cells come together as an assembly, such as in a strap or frame, to form a single unit assembly.

[0041] On the other hand, if thermal runaway occurs in some battery cells or battery modules 300 inside the battery pack, gases or flames ejected from those cells or modules 300 can propagate to other adjacent cells or modules 300 inside the battery pack. In such cases, a fire throughout the entire battery pack or secondary damage due to flame propagation to the outside can occur very quickly due to flames or gas attacks between adjacent battery cells or modules 300. Therefore, it is necessary to minimize and delay as much as possible the possibility of flame propagation from a thermally runaway battery cell or battery module 300 to an adjacent battery cell or module 300.

[0042] Conventionally, when thermal runaway occurred in some cells or modules 300 inside the battery pack, a large pressure was generated by the gas or flames ejected from the affected cells or modules 300. This instantaneous high pressure caused the module cover 320 covering the module 300 to lift up, resulting in the propagation of gas or flames to adjacent cells or modules 300, which led to the problem of rapid propagation of gas or flames inside the battery pack.

[0043] According to the present invention, in such cases, the gas and flames of the cell experiencing the problem are vented smoothly and without resistance, while at the same time, the module cover 320 does not lift up and stably pressurizes and covers the module 300, thus preventing the propagation of gas and flames to adjacent cells or modules 300.

[0044] Specifically, a module cover 320 is attached to the battery module 300 of the present invention, as shown in Figure 1. The battery module 300 is composed of multiple battery cells, and the module cover 320 is attached to the upper or side ends of the cells to protect the battery module 300 in the event of a fire in an adjacent module 300. In the illustrated embodiment, the module cover 320 is shown to be attached to the upper end of the module 300, but the module cover 320 is not necessarily limited to this, and can be fixed to various points such as the side ends or lower ends of the module 300 to cover the cells that make up the module 300.

[0045] On the other hand, since the module cover 320 must protect the cells of the battery module 300 from gases and flames, it can be molded from a refractory material such as mica. Through molding with such a material, the module cover 320 blocks high-temperature external gases and flames from flowing into the module 300.

[0046] Furthermore, the module cover 320 must be configured to vent gas and flames in the event of thermal runaway of the battery cells. Therefore, a venting section 322 is formed in the module cover 320 as shown in Figure 1. The venting section 322 must normally cover the battery module 300 to prevent the inflow of external gas and flames, and in the event of thermal runaway of the cells located below it, only the necessary points of the venting section 322 must be activated to allow the venting of gas and flames generated inside. For this reason, the venting section 322 is shaped with only a portion cut out, as shown in the figure, so that it is opened to the outside only when necessary. In addition, various shapes of venting sections 322 can be applied as long as they satisfy the conditions of performing the covering role well under normal circumstances and being opened under high pressure only when necessary.

[0047] The venting section 322 separates from the module cover 320 to form a venting hole when a battery cell located below the venting section 322 experiences thermal runaway, allowing gas and flames generated from the cell to be vented to the outside of the module 300 through the formed venting hole. Simultaneously with venting at the venting hole, flame propagation to adjacent battery cells must be prevented. Therefore, the module cover 320 must vent well where high pressure is applied, while also covering the cells well at adjacent points to prevent flame propagation. In other words, even if a high-temperature, high-pressure atmosphere is created inside the module cover 320, the module cover 320 must adequately pressurize the module 300.

[0048] Conventionally, to achieve this role, foam ropes made of materials such as foamed silicone were used to pressurize the module cover 320 from the pack lead 140. However, in high-temperature conditions due to thermal runaway, thermal deformation of the foam rope occurred, resulting in a weak pressurizing force. Furthermore, the weakened pressurizing force of the foam rope caused the module cover 320 to lift, leading to the propagation of gas and flames to adjacent cells and modules 300, increasing the risk of structural collapse inside the battery pack and failing to adequately ensure the stability of the battery pack.

[0049] As a result, in this invention, pressurization is performed using a fire-resistant material instead of foam rope. Furthermore, when supporting the pressurizing structure with the module cover 320 or pack case 100, it is characterized by being supported by a cap made of fire-resistant and insulating material. Through this, even when flames are generated, the biasing force does not change and the module cover 320 is continuously pressurized, preventing the propagation of flames and performing pressurization without impairing the existing venting effect. In addition, even if pressurization is performed using a metal material to ensure fire resistance, the risk of short circuits between the module 300 and the pack case 100 is reduced because the cap supporting it is made of an insulating material.

[0050] Specifically, the present invention presents a battery system comprising a biasing section 500 supported between a pack case 100 and a battery module 300, wherein the biasing section 500 is supported at its end by a cap made of fire-resistant material.

[0051] The battery module 300 includes a module cover 320, and the outer surface of the battery module 300 facing the pack case 100 is provided with a venting section 322 that includes venting holes to expel gas and flames to the outside in the event of thermal runaway of the battery cells, and the biasing section 500 is positioned to avoid the venting section 322 as shown in Figure 1. Through this arrangement, gas and flames are smoothly vented to the outside in the event of thermal runaway of the battery cells, and at the same time, the propagation of flames to adjacent battery cells and modules 300 can be effectively prevented.

[0052] As shown in Figure 5, the biasing section 500 consists of a first cap 520 at both ends, a second cap 560, and a biasing body 540, with the biasing body 540 positioned between the first cap 520 and the second cap 560. The first cap 520 and the second cap 560, which are the ends of the biasing section 500, can be made of fire-resistant material because they must prevent the propagation of gas and flames to adjacent cells or modules 300 when thermal runaway occurs inside the battery cells or battery modules 300. Furthermore, the end caps must be lightweight and have good insulation properties among fire-resistant materials, so they can be made of mica (MICA) or the like.

[0053] In the case of the biasing body 540 of the pressurizing biasing unit 500, it must be resistant to high-temperature, high-pressure gases and flames, so a metal spring or the like may be considered. However, if a metal biasing body 540 is used, ensuring insulation between the pack case 100 and the battery module 300 is essential, so the caps covering both ends of the biasing unit 500 must have not only fire resistance but also insulation properties. Through the selection of such cap materials, the biasing unit 500 of the present invention will transmit the necessary pressurizing force to the module 300 while simultaneously ensuring insulation in thermal runaway situations. Of course, the battery system of the present invention is not limited to the materials and shapes presented above.

[0054] The pack case 100 may consist of a case body 120 and a pack lead 140 for ease of assembly. The case body 120 may have an open top, an open bottom, or, in some cases, open sides, and the pack lead 140 performs the function of closing the open surface of the case body 120. As shown in Figure 1, the case body 120 forms an internal space with its bottom and side walls, and the battery module 300 is installed inside through the open top surface in the open top surface configuration. The open top surface of the case body 120 is then closed through the pack lead 140. In the event of thermal runaway in the battery module 300, the inside of the pack case 100 is created in a high-temperature, high-pressure environment. Therefore, if gas or flames are generated due to thermal runaway in the battery cells or battery module 300, the pack lead 140 can easily undergo thermal deformation due to expansion. This expansion widens the gap between the expanded portion and the module cover 320, reducing the pressurizing force on the module cover 320 and potentially causing the module cover 320 to lift up.

[0055] The present invention aims to prevent the module cover 320 of the battery module 300 from lifting even if the case body 120 or pack lead 140 expands, thereby minimizing the risk of heat transfer, while simultaneously facilitating smooth gas venting.

[0056] In the case of the biasing unit 500, it is installed between the pack case 100 and the battery module 300, and the first cap 520 of the biasing unit 500 is fixed in a state where it is inserted into the second cap 560, maintaining a compressed state of the biasing body 540 between the first cap 520 and the second cap 560. If thermal runaway occurs in the battery cells or battery module 300, the high-pressure gas and high-temperature flames will cause the battery module 300 or module cover 320 to lift up, easily exposing it to the propagation of gas and flames to adjacent cells or modules 300. To prevent the battery module 300 or module cover 320 from lifting up even if thermal runaway occurs as shown in Figure 3, the first cap 520 of the biasing unit 500 may be provided in close contact with the lower end of the pack lead 140, and the second cap 560 may be provided in close contact with the upper end of the module cover 320. When the lower end of the pack lead 140 and the upper end of the module cover 320 are in close contact, they are attached and fixed with an adhesive, in which case the adhesive may be made of a heat-resistant material that can withstand high temperatures and pressures due to thermal runaway.

[0057] On the other hand, as shown in Figure 4, the first cap 520 and the second cap 560 of the biasing portion 500 may also be positioned on the side of the battery system. In this case, the first cap 520 may be in close contact with the side of the case body 120, and the second cap 560 may be in close contact with the side of the battery module 300. When in close contact with the side of the case body 120 or the battery module 300, they may be attached and fixed with an adhesive, and in this case as well, the adhesive must be made of a heat-resistant material.

[0058] The biasing portion 500 may be provided in close contact with the case body 120 or pack lead 140 and the battery module 300 or module cover 320. In this case, since the biasing portion 500 is exposed to instantaneous high pressure and high temperature when thermal runaway occurs in the battery cell or battery module 300, it is important to fix the first cap 520 and the second cap 560 with a heat-resistant adhesive. Only by using a heat-resistant adhesive can the biasing portion 500 be fixed without deformation of the adhesive even under high pressure and high temperature conditions, and since the first cap 520 and the second cap 560 are made of fire-resistant material, the biasing portion 500 can also be fixed without deformation. Therefore, even if thermal runaway occurs, the case body 120 or pack lead 140 and the battery module 300 or module cover 320 can be stably supported, and the propagation of gas and flame to adjacent cells or modules 300 can be minimized or delayed over time.

[0059] On the other hand, if the biasing section 500 is stretched even before assembly, there is a possibility of misassembly during the assembly of the pack lead 140 and the case body 120. Therefore, it is desirable that the biasing section 500 has its first cap 520 and second cap 560 assembled together during assembly and under normal conditions after assembly, so that the biasing body 540 remains compressed between them. Accordingly, as shown in Figure 2, the first cap 520 of the biasing section 500 is fixed in a state inserted into the second cap 560, and the biasing body 540 remains compressed between the first cap 520 and the second cap 560.

[0060] However, in the event of thermal runaway in the biasing unit 500, as shown in Figure 5, the first cap 520 and the second cap 560 must be separated and the biasing body 540 must be extended. Therefore, a configuration is needed that allows the first cap 520 and the second cap 560 to be separated in a high-temperature environment. Referring to Figure 8, the first cap 520 and the biasing body 540 of the biasing unit 500 may be provided to be inserted into the second cap 560 by forcibly fitting them into place. In this case, the first cap 520 of the biasing unit 500 normally remains fitted into the second cap 560, but is pulled out from the second cap 560 when the temperature inside the pack case 100 rises due to gas or flames generated in the battery cells or battery module 300, and the biasing body 540 is extended and activated by the pulling out of the first cap 520.

[0061] Since the first cap 520 and biasing body 540 of the biasing section 500 must be inserted into the second cap 560, the inner diameter of the second cap 560 will have the same shape as the outer diameter of the first cap 520. Through this, the first cap 520 and the second cap 560 are assembled to each other by force-fitting.

[0062] Figure 9 is a drawing showing a biasing member 500 according to another embodiment of the present invention. In this case, a ring or projection 580 is formed between the first cap 520 and the second cap 560, and when the first cap 520 is inserted into the second cap 560, it can be compressed into a locked and fixed form. When compressed into a locked and fixed form, the ring or projection 580 softens under high pressure and high temperature conditions due to thermal runaway, causing the first cap 520 to be pulled out from the second cap 560, and the biasing member 540 is stretched and activated by the pulling out of the first cap 520. In such a locked and fixed form, the second cap 560 can be manufactured by forming the ring or projection 580 together with the inner surface when the second cap 560 is molded, or by attaching the ring or projection 580 to the inner surface of the second cap 560 or the outer surface of the first cap 520. One or more rings or projections 580 are present and can be positioned between the first cap 520 and the second cap 560 to increase the coupling. By fastening such a locking mechanism using rings or projections 580, a mutually mechanical connection can be realized without the need for separate adhesives.

[0063] In yet another embodiment of the present invention, as shown in Figure 10, the outer surface of the first cap 520 and the inner surface of the second cap 560 may be fixed using an adhesive 590. In this case, the adhesive 590 melts due to high-temperature gas or flame, causing the biasing body 540 to operate. The adhesive 590 serves to fix both ends of the first cap 520 when it is inserted into the second cap 560, and under high pressure and high temperature conditions due to thermal runaway, the adhesive strength of the adhesive 590 is lost, causing the first cap 520 to separate from the second cap 560 and stretch. Therefore, the adhesive 590 must be made of a material that maintains its adhesive strength at room temperature but loses its adhesive strength under high-temperature conditions.

[0064] The first cap 520 and the second cap 560 are formed in the shape of a plug with one side open, as shown in Figures 2 and 5. Specifically, the first cap 520 and the second cap 560 have a bottom surface that makes surface contact with the case body 120 or pack lead 140 and the battery module 300 or module cover 320, and a side wall connected to this bottom surface, with the opposite side of the bottom surface being open, and the open surfaces facing each other. Of course, the first cap 520 and the second cap 560 can be provided in various shapes, not just the circular shape as shown in Figure 2, as long as surface contact is possible. Furthermore, since the first cap 520 and the second cap 560 must prevent the propagation of gas and flame to adjacent cells or modules 300 when thermal runaway occurs inside the battery cells or battery module 300, they must be made of fire-resistant material, and among fire-resistant materials, they must have insulating properties and be lightweight, so they can be made of mica (MICA) or the like. Through the shape and surface contact method of the first cap 520 and the second cap 560, the assembly stability of the battery system of the present invention can be enhanced, and at the same time, the biasing force of the biasing part 500 can be increased during thermal runaway, thereby minimizing or delaying the heat propagation to adjacent cells and modules 300 during thermal runaway.

[0065] The pack case 100 is composed of a case body 120 and pack leads 140 for ease of assembly. In the case of batteries mounted in vehicles, performance against collisions must be ensured, and in the event of an internal fire, the spread to the outside must be prevented. Therefore, the pack case 100 can be molded from a metal material. Among metals, it can be molded from aluminum because it must be formable and lightweight. In the case of a pack case 100 made of a metal material such as aluminum, thermal deformation due to expansion can occur in high-pressure or high-temperature environments caused by thermal runaway in some battery cells or battery modules 300, and the amount of expansion can vary from point to point even within a single pack case 100.

[0066] Referring to Figure 11, in the case of the outer part B away from the center of the pack case 100, the case body 120 is molded as a housing with the sides and bottom integrally formed, and the pack lead 140 is also connected to the case body 120 by various methods such as welding, bonding, and mechanical fastening, so even if thermal runaway occurs, the amount of expansion is relatively small. On the other hand, in the case of the central part A of the pack case 100, the case body 120 has a wide surface shape to accommodate the battery module 300, and the pack lead 140 is not directly connected to the case body 120, so this is the point where the amount of expansion is greatest when thermal runaway occurs. In other words, when thermal runaway occurs, the pack lead 140 expands more the closer it is to the central part A.

[0067] Multiple biasing units 500 are provided between the pack case 100 and the battery module 300. Considering that the amount of expansion of the pack lead 140 can vary at different points, it is appropriate to arrange the biasing units 500 so that the elastic modulus or compressibility of the biasing body 540 is greater closer to the central part A of the pack lead 140 (for example, biasing unit 500A is greater than biasing unit 500B). By arranging the biasing units 540 with a larger elastic modulus or compressibility closer to the central part A of the pack lead 140, the biasing force of the biasing units 500 increases closer to the central part A of the pack lead 140. This allows the biasing units 500 inside the pack case 100 to operate in a balanced manner, thereby ensuring sufficient stability of the entire battery system. In this case, if the lengths of the biasing bodies 540 of the multiple biasing parts 500 located inside the pack case 100 are the same, the biasing force can be adjusted by using materials with different elastic moduli. If the elastic moduli of the biasing bodies 540 are the same, it would be possible to tune the biasing forces to be different by varying the lengths of the biasing bodies 540 to create different compression amounts.

[0068] A module cover 320 is attached to the battery module 300 of the present invention. The module cover 320 covers one side of the battery module 300 to protect the battery module 300 and the battery cells located inside from gas and flames. A biasing unit 500 may be provided between the pack case 100 and the module cover 320 to prevent the propagation of gas and flames to adjacent cells or modules 300 in the event of thermal runaway in the battery cells or battery module 300. When high-pressure gas or high-temperature flames are generated in such a location, the biasing unit 500 will expand as shown in Figure 6, and the first cap 520 or the second cap 560 of the biasing unit 500 will be supported by the pack case 100 or the module cover 320, respectively, pressurizing the module cover 320 relative to the pack case 100, thereby preventing gas and flames from flowing into the battery module 300.

[0069] In another embodiment, the biasing portion 500 may be positioned between the pack case 100 and the module cover 320, with one end of the biasing portion 500 fixed only to the module cover 320. As explained above, the amount of expansion due to thermal runaway inside the pack case 100 may differ depending on the location. Also, the amount of expansion is greater closer to the central part A of the pack lead 140, so as a result the pack lead 140 expands into an arch shape. As a result, when the pack lead 140 expands, the central part A expands into a relatively horizontal shape, while at locations other than the central part, it expands into a shape with a diagonally inclined surface. In such a case, if the biasing portion 500 is attached not only to the module cover 320 but also to the pack case 100, when the pack case 100 expands due to thermal runaway, the biasing portion 500 attached to the diagonally inclined surface of the pack case 100 may experience unstable surface contact, making it impossible to sufficiently pressurize the battery module 300 or module cover 320 relative to the pack case 100. Therefore, the biasing part 500 can be fixed only to the module cover 320 side, with one end fixed to the module cover 320 and the other end spaced apart from the pack case 100. Subsequently, if thermal runaway occurs in the battery cell or battery module 300, the biasing part 500 will be stretched by the gas and flame inside the pack case 100. When the biasing part 500 is stretched, both ends of the biasing part 500 will be supported by the pack case 100 and the module cover 320 respectively, allowing the module cover 320 to be sufficiently pressurized with respect to the pack case 100.

[0070] On the other hand, the pack case 100 includes a case body 120 with one side open and a pack lead 140 that closes the open portion of the case body 120, and a biasing part 500 may be provided between the pack lead 140 and the battery module 300. If thermal runaway in the battery cells or battery module 300 generates high-pressure gas or high-temperature flames, the pack lead 140 will expand, and the expansion of the pack lead 140 will also increase the distance between the pack lead 140 and the battery module 300. The biasing part 500 provided between the pack lead 140 and the battery module 300 will stretch by the distance between the pack lead 140 and the battery module 300, and both ends may be supported by the pack lead 140 and the battery module 300, respectively. Therefore, the biasing part 500 can pressurize the battery module 300 with respect to the pack lead 140 to prevent the propagation of gas or flames to adjacent battery cells or battery modules 300, and can delay heat propagation in terms of time.

[0071] The battery system according to the present invention can be applied to battery systems for a variety of vehicles, including internal combustion engine vehicles, electric vehicles, hybrid vehicles, and fuel cell vehicles. In addition to vehicles, it can also be applied to battery systems in various fields, such as industrial ESS (Energy Storage Systems), household ESS, and small battery packs.

[0072] Although illustrated and described in relation to specific embodiments of the present invention, it will be obvious to those ordinary in the art that the present invention can be improved and modified in various ways without departing from the technical spirit of the invention provided by the claims below. [Explanation of symbols]

[0073] 100 pack case 120 Case Body 140 Pack Lead 300 Battery Modules 320 Module Cover 322 Venting section 500 biasing section 520 First cap 540 biasing body 560 Second cap 580 Ring or protrusion 590 Adhesive A Central part B Outer part

Claims

1. Battery module and A pack case in which the aforementioned battery module is installed, A battery system comprising: a biasing unit installed between the pack case and the battery module, pressurizing the battery module relative to the pack case, and having an end supported by the pack case or the battery module through a cap made of fire-resistant material.

2. The battery system according to claim 1, characterized in that a venting portion is formed on the outer surface of the battery module facing the pack case, and the biasing portion is positioned at a point that avoids the venting portion.

3. The battery system according to claim 1 or 2, characterized in that the biasing portion comprises a first cap, a second cap, and a biasing body, and the biasing body is located between the first cap and the second cap.

4. The battery system according to claim 3, characterized in that the first cap of the biasing portion is in close contact with the inner surface of the pack case, and the second cap is in close contact with the outer surface of the battery module.

5. The battery system according to claim 3, characterized in that the first cap or the second cap of the biasing portion is attached with an adhesive to the inner surface of the pack case or the outer surface of the battery module, and the adhesive is made of a heat-resistant material.

6. The first cap of the biasing portion is fixed in a state where it is inserted into the second cap, and the biasing body is maintained in a compressed state between the first cap and the second cap. The battery system according to claim 3, characterized in that the first cap of the biasing portion is pulled out from the second cap by gas or flame generated from the battery module or by a rise in the internal temperature of the pack case, and the biasing body is extended by the pulling out of the first cap.

7. The battery system according to claim 6, characterized in that the first cap of the biasing portion is locked and fixed in a state where it is inserted into the second cap, and the first cap separates from the second cap when the second cap expands due to high temperature.

8. The battery system according to claim 6, characterized in that the first cap of the biasing portion is fixed by adhesive while inserted into the second cap, and the first cap separates from the second cap when the adhesive force is lost due to high temperature.

9. Multiple biasing units are provided between the pack case and the battery module, and the biasing force increases as the biasing unit approaches the center of the pack case. The battery system according to claim 1 or 2, characterized in that the biasing portion closer to the center of the pack case has a greater elastic modulus or compression amount than the biasing portion further away from the center of the pack case.

10. A module cover is attached to the battery module to cover one side of the battery module, and the biasing portion is provided between the pack case and the module cover. The battery system according to claim 1 or 2, characterized in that the biasing portion is positioned between the pack case and the module cover and fixed to the module cover.

11. The battery system according to claim 10, characterized in that one end of the biasing portion is fixed to the module cover and the other end is spaced apart from the pack case.

12. The battery system according to claim 10, characterized in that the biasing portion is expanded by gas or flame or high temperature inside the pack case, and when the biasing portion is expanded, both ends of the biasing portion are supported by the pack case and the module cover, respectively.

13. The battery system according to claim 1 or 2, characterized in that the pack case includes a case body with one side open and a pack lead that closes the case body, and the biasing portion is located between the pack lead and the battery module.

14. The battery system according to claim 13, characterized in that when gas, flames, or high temperatures are generated inside the pack case, the pack leads expand, increasing the distance between the pack leads and the battery module, and the biasing portion stretches as the distance between the pack leads and the battery module increases, thereby pressurizing the battery module with respect to the pack leads.

15. A vehicle characterized by including the battery system described in claim 1 or 2.

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