System for thermal propagation evaluation and method using thereof

Abstract

The present invention relates to a heat propagation evaluation system and a method thereof. The heat propagation evaluation method according to the present invention includes the steps of: machining a hole in the long side portion of a battery can; attaching a heater by penetrating the area where the hole is formed; and performing sealing on the area where the hole is formed.

Description

Technology Field

[0001] The present invention relates to a heat propagation evaluation system and a method thereof. Background Technology

[0003] According to conventional technology, external physical impact testing (nail penetration test) and external heater heating methods have been proposed in relation to battery thermal runaway simulation technology. The external physical impact test involves using a metal nail from the outside of the battery cell to penetrate the cell and artificially induce an internal short circuit, which has the problem that physical damage is inevitable. In addition, the external heater heating method has the problem that it is difficult to properly simulate the thermal runaway phenomenon because it is difficult to achieve complete heat isolation even when insulation is applied to adjacent cells rather than the target cell.

[0004] According to conventional technology, a method has been proposed to induce thermal runaway through heating by inserting a heater inside the cell; however, since this requires inserting the heater inside the cell and then undergoing the electrolyte injection and formation processes during cell manufacturing, there is a problem in that there is a high risk of ignition during formation and it is difficult to secure good quality cells. The problem to be solved

[0006] The present invention is proposed to solve the aforementioned problems and aims to provide a heat propagation evaluation system and method capable of generating thermal runaway without physical damage to the can and without additional heat transfer to adjacent cells.

[0007] However, the technical problems that the present invention aims to solve are not limited to those described above, and other unmentioned problems can be clearly understood by those skilled in the art from the description of the invention below. means of solving the problem

[0009] The heat propagation evaluation method according to the present invention includes the steps of: machining a hole in the long side portion of a battery can; attaching a heater by penetrating the area where the hole is formed; and performing sealing on the area where the hole is formed.

[0010] The step of machining a hole in the long side portion of the battery can involves machining a hole of a preset shape in the long side portion of the rectangular battery for vehicles.

[0011] The step of attaching the heater involves attaching a film-type heater to the outer surface of the stack inside the cell.

[0012] The step of performing the sealing above involves placing the detached portion from the hole processing step into the space prior to detachment, and performing sealing using a special adhesive or heat treatment.

[0013] The step of performing the sealing above involves performing sealing on the area where the hole is formed using a safety evaluation jig.

[0014] The above jig includes a protruding structure corresponding to the size and shape of the area where the hole is formed.

[0015] The height of the above protruding structure is formed to be less than or equal to the height of the area where the hole is formed.

[0016] At least one of a temperature sensor and a pressure sensor is disposed inside the above-mentioned protruding structure.

[0017] The thermal propagation evaluation system according to the present invention includes a memory storing a control program for simulating a battery cell thermal runaway phenomenon and a processor for executing the program, wherein the processor applies heat using a heater attached to a hole and transmits a control command to cause thermal runaway to occur.

[0018] The height of the above protruding structure is formed to be less than or equal to the height of the area where the hole is formed.

[0019] The thermal propagation evaluation device according to the present invention includes a heater that is inserted into and attached to the interior through a hole area formed in a battery can, and a sealing member that performs sealing on the hole area.

[0020] The above heater is attached in a film type to a predetermined area of ​​the outer surface of the cell stack through the hole area formed in the long side of the battery can.

[0021] The above-mentioned sealing member is a protruding structure disposed on one surface of a safety evaluation jig, wherein the protruding structure is formed to correspond to the size and shape of the hole area, and the height of the protruding structure is formed to be less than or equal to the height of the hole area. Effects of the invention

[0023] According to the present invention, in an evaluation system for determining whether thermal runaway of adjacent cells occurs due to thermal runaway of a specific cell in a rectangular cell module or pack, there is an effect that it is possible to artificially induce thermal runaway of a specific cell.

[0024] The effects of the present invention are not limited to those mentioned above, and other unmentioned effects will be clearly understood by those skilled in the art from the description below. Brief explanation of the drawing

[0026] The following drawings attached to this specification illustrate preferred embodiments of the present invention and serve to further enhance understanding of the technical concept of the present invention together with the detailed description of the invention provided below; therefore, the present invention should not be interpreted as being limited only to the matters described in such drawings. Figure 1 schematically illustrates a secondary battery electrode assembly. Figure 2 schematically shows the configuration of a pouch-type secondary battery. Figure 3 shows the schematic external configuration of a prismatic secondary battery. Figure 4 is a cross-sectional view of a cylindrical secondary battery. FIG. 5 illustrates a heat propagation evaluation system according to an embodiment of the present invention. FIG. 6 illustrates the jig structure of a heat propagation evaluation system according to an embodiment of the present invention. FIG. 7 illustrates a heat propagation evaluation method according to an embodiment of the present invention. FIG. 8 is a block diagram showing a computer system for implementing a method according to an embodiment of the present invention. FIG. 9 is an exemplary diagram of a secondary battery module with a secondary battery arranged according to the present invention. FIG. 10 is an example of a secondary battery pack including the secondary battery module of FIG. 9. FIG. 11 is a conceptual diagram of a vehicle including the secondary battery pack of FIG. 10. Specific details for implementing the invention

[0027] 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 claims should not be interpreted as being limited to their ordinary or dictionary meanings. Instead, based on the principle that the inventor can appropriately define the concepts of terms to best describe their invention, they should be interpreted in a meaning and concept consistent with the technical spirit of the present invention. Therefore, the embodiments described in this specification and the configurations illustrated in the drawings are merely some of the most preferred embodiments of the present invention and do not represent all of the technical spirit of the present invention. It should be understood that various equivalents and modifications capable of replacing them may exist at the time of filing this application.

[0028] Additionally, as used herein, “comprise, include” and / or “comprising, including” specify the presence of the mentioned features, numbers, steps, actions, parts, elements, and / or groups thereof, and do not exclude the presence or addition of one or more other features, numbers, actions, parts, elements, and / or groups.

[0029] Additionally, to aid in understanding the invention, the attached drawings are not drawn to actual scale, and the dimensions of some components may be exaggerated. Furthermore, the same reference numerals may be assigned to identical components in different embodiments.

[0030] The statement that two subjects of comparison are 'identical' means that they are 'substantially identical.' Therefore, substantial identity may include deviations considered low in the industry, for example, deviations within 5%. Additionally, the statement that a parameter is uniform in a given area may mean that it is uniform from an average perspective.

[0031] Although terms such as "first," "second," etc., are used to describe various components, it goes without saying that these components are not limited by these terms. These terms are used merely to distinguish one component from another, and unless specifically stated otherwise, the first component may also be the second component.

[0032] Throughout the specification, unless specifically stated otherwise, each component may be singular or plural.

[0033] The fact that any configuration is placed on the "upper (or lower)" of a component or on the "upper (or lower)" of a component may mean not only that any configuration is placed in contact with the upper (or lower) surface of said component, but also that another configuration may be interposed between said component and any configuration placed on (or below) said component.

[0034] Furthermore, where one component is described as being "on," "connected to," or "coupled to" another component, it should be understood that while the components may be directly connected or coupled to each other, another component may be "interposed" between each component, or each component may be "connected," "coupled," or "coupled" through another component.

[0035] As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed items. Additionally, the use of “may” when describing embodiments of the present disclosure relates to “one or more embodiments of the present disclosure.” Expressions such as “one or more” and “one or more” preceding a list of elements modify the entire list of elements and do not modify individual elements of the list.

[0036] Throughout the specification, "A and / or B" means A, B, or A and B unless specifically stated otherwise, and "C to D" means C or more and D or less, unless specifically stated otherwise.

[0037] When syntax such as "at least one of A, B, and C", "at least one of A, B, or C", "at least one selected from the group of A, B, and C", or "at least one selected from A, B, and C" is used to specify a list of elements A, B, and C, the syntax can refer to any suitable combination.

[0038] The term "use" may be considered synonymous with the term "utilize." As used herein, "substantially," "about," and similar terms are used as terms of approximation rather than degree, and are intended to account for the inherent variation of measured or calculated values ​​that a person skilled in the art would recognize.

[0039] In this specification, terms such as first, second, third, etc. may be used to describe various elements, components, regions, layers, and / or sections, but these elements, components, regions, layers, and / or sections should not be limited by these terms. These terms are used to distinguish one element, component, region, layer, or section from another element, component, region, layer, or section. Accordingly, the first element, component, region, layer, or section discussed below may be named the second element, component, region, layer, or section without departing from the teachings of the exemplary embodiments.

[0040] Spatial relative terms such as "beneath," "below," "lower," "above," and "upper" may be used herein for ease of explanation to describe the relationship between one element or feature and another element(s) or feature(s) as illustrated in the drawings. Spatially relative positions are to be understood as encompassing different orientations of the device in use or operation, in addition to the orientations depicted in the figures. For example, if the device in the drawing is inverted, an element described as "below" or "below" is understood as "above" or "upper" of another element. Thus, the term "below" may encompass both the up and down directions.

[0041] The terms used in this specification are intended to describe embodiments of the present disclosure and are not intended to limit the present disclosure.

[0042] Figure 1 schematically illustrates an electrode assembly embedded in a secondary battery casing.

[0043] The electrode assembly (10) may be formed by winding or stacking a laminate of a first electrode plate (11), a separator (12), and a second electrode plate (13) formed in a plate or film shape. If the electrode assembly (10) is a wound laminate, the winding axis may be parallel to the longitudinal direction of the case (not shown). Additionally, the electrode assembly (10) may be a stack type rather than a wound type, but the present invention does not limit the shape of the electrode assembly (10). Furthermore, the electrode assembly (10) may be a Z-stack electrode assembly in which the first electrode plate and the second electrode plate are inserted on both sides of a separator bent into a Z shape. Additionally, one or more electrode assemblies (10) may be stacked so that their long sides are adjacent to each other and housed inside the case, but the present invention does not limit the number of electrode assemblies. The first electrode plate (11) of the electrode assembly (10) can act as a negative electrode and the second electrode plate (13) can act as a positive electrode, and the opposite is also possible.

[0044] The first electrode plate (11) is formed by applying a first electrode active material, such as graphite or carbon, to a first substrate formed of a metal foil such as copper, a copper alloy, nickel, or a nickel alloy, and may include a first electrode tab (or first uncoated portion) (14), which is an area where the first electrode active material is not applied. The first electrode tab (14) may be connected to an external first terminal (not shown). In some examples, the first electrode tab (14) may be formed by cutting it to protrude to one side in advance when manufacturing the first electrode plate (11), and may protrude further to one side than the separator (12) without separate cutting.

[0045] The second electrode plate (13) is formed by applying a second electrode active material, such as a transition metal oxide, to a substrate formed of a metal foil such as aluminum or an aluminum alloy, and may include a second electrode tab (or second uncoated portion) (15), which is an area where the second electrode active material is not applied. The second electrode tab (15) may be connected to an external second terminal (not shown). In some examples, the second electrode tab (15) may be formed by cutting it to protrude to the other side in advance when manufacturing the second electrode plate (13), and may protrude further to the other side than the separator (12) without separate cutting.

[0046] In some embodiments, the first electrode tab (14) may be located on the right end side of the electrode assembly (10), and the second electrode tab (15) may be located on the left end side of the electrode assembly (10), or on one side in the same direction. Also, in some embodiments, the first electrode tab (14) and the second electrode tab (15) may be located on the top of the electrode assembly (10).

[0047] Here, the left, right, and top are for convenience of explanation based on the electrode assembly (10) shown in FIG. 1, and their positions may change when the secondary battery rotates left and right or up and down.

[0048] The separator (12) functions to prevent short circuits between the first electrode plate (11) and the second electrode plate (13) while allowing the movement of lithium ions. The separator (12) may be composed of, for example, a polyethylene film, a polypropylene film, a polyethylene-polypropylene film, etc.

[0049] In some embodiments, the electrode assembly (10) may be housed in an outer material (not shown) and filled with an electrolyte. In the case of a pouch-type secondary battery, the electrode assembly (10) may be housed in a pouch of a flexible material in the form shown in FIG. 1, and in the case of a prismatic secondary battery, the electrode assembly (10) may be housed in a prismatic metal case in the form shown in FIG. 1.

[0050] Figure 2 schematically shows a pouch-type secondary battery.

[0051] A pouch-type secondary battery consists of an electrode assembly (10) and a pouch (20) that accommodates the electrode assembly (10).

[0052] The electrode assembly (10) is as shown in FIG. 1, and the first electrode tab (14) and the second electrode tab (15) of the electrode assembly (10) can be electrically connected by welding to the external first terminal lead (16) and the second terminal lead (17), respectively. A tab film (18) for insulation from the pouch (20) can be attached to the first terminal lead (16) and the second terminal lead (17).

[0053] The pouch (20) can be sealed by the sealing portions (21) at the edges coming into contact with each other while the pouch (20) accommodates the electrode assembly (10), and sealing can be performed with a tab film (18) interposed between the sealing portions (21). The sealing portions (21) of the pouch (20) are made of a heat-fusion material, and since heat-fusion materials generally have weak adhesion to metal, a thin film-shaped tab film (18) can be interposed to fuse with the pouch (20).

[0054] Figure 3 shows the schematic external configuration of a prismatic secondary battery.

[0055] A rectangular case (51) forms the overall exterior of the rectangular secondary battery and may be formed of a conductive metal such as aluminum, aluminum alloy, or nickel-plated steel. Additionally, the case (51) may provide a space for accommodating the electrode assembly (10).

[0056] The cap assembly (60) may include a cap plate (61) covering the opening of the case (51), and the case (60) and the cap plate (61) may be made of a conductive material. Here, the first terminal (63) and the second terminal (62) may be electrically connected to the first electrode tab (14) and the second electrode tab (15) of the electrode assembly (10) inside, and installed to protrude outward by penetrating the cap plate (61).

[0057] The cap plate (61) may have an electrolyte injection port (64) into which a sealing plug can be installed, and a vent (66) with a notch (65) formed therein may be installed. The vent (66) is intended to degas gas generated inside the battery.

[0058] Figure 4 is a cross-sectional view of a cylindrical secondary battery.

[0059] A cylindrical secondary battery comprises an electrode assembly (30), a case containing the electrode assembly (30) and an electrolyte, a cap assembly (50) coupled to an opening of the case to seal the case, and an insulating plate (37) located between the electrode assembly (30) and the cap assembly (50) inside the case.

[0060] The electrode assembly (30) may include a separator (32), a first electrode (33) and a second electrode (31) positioned between the separator (32), and may be wound in the form of a jelly-roll.

[0061] The first electrode (33) includes a first substrate and a first active material layer located on the first substrate. A first lead tab (35) may extend outwardly from a first non-active portion of the first substrate where the first active material layer is not located, and the first lead tab (35) may be electrically connected to a cap assembly (50).

[0062] The second electrode (31) includes a second substrate and a second active material layer located on the second substrate. A second lead tab (34) may extend outwardly from a second non-active portion of the second substrate where the second active material layer is not located, and the second lead tab (34) may be electrically connected to the case (10). The first lead tab (35) and the second lead tab (34) may extend in opposite directions.

[0063] The first electrode (33) can function as a positive electrode. In this case, the first substrate may be composed of, for example, aluminum foil, and the first active material layer may include, for example, a transition metal oxide. The second electrode (31) can function as a negative electrode. In this case, the second substrate may be composed of, for example, copper foil or nickel foil, and the second active material layer may include, for example, graphite.

[0064] The separator (32) functions to prevent short circuits between the first electrode (33) and the second electrode (31) while allowing the movement of lithium ions. The separator (32) may be composed of, for example, a polyethylene film, a polypropylene film, a polyethylene-polypropylene film, etc.

[0065] The case accommodates the electrode assembly (30) and the electrolyte, and together with the cap assembly (50), forms the outer shape of the battery. The case may include a body portion (42) with an approximate cylindrical shape and a bottom portion (41) connected to one side of the body portion (42). A beading portion (43) deformed toward the inside may be located on the body portion (42), and a crimping portion (45) bent toward the inside may be located at the opening end of the body portion (42).

[0066] The beading portion (43) can prevent the electrode assembly (30) from moving inside the case and facilitate the seating of the gasket (44) and the cap assembly (50). The crimping portion (45) can firmly secure the cap assembly (50) by pressing the edge of the cap assembly (50) through the gasket (44). The case may be made of, for example, nickel-plated iron.

[0067] The cap assembly (50) can be secured to the inside of the crimping portion (45) through a gasket (44) to seal the case. The cap assembly (50) may include a cap up, a safety vent, a cap down, an insulating member, and a subplate, but is not limited to these examples and can be modified in various ways.

[0068] The cap-up may be located at the uppermost part of the cap assembly (50). The cap-up may include a terminal portion that protrudes upward in a convex manner to be connected to an external circuit, and a discharge port for discharging gas may be located around the terminal portion.

[0069] The safety vent may be located below the cap-up. The safety vent may include a protrusion that protrudes convexly downward and connects to a subplate, and at least one notch located around the protrusion.

[0070] In the event that gas is generated due to overcharging or abnormal operation of the secondary battery, the protrusion is deformed upward by pressure and separated from the subplate, while the safety vent can be cut along the notch. The cut safety vent can release the gas to the outside to prevent the explosion of the secondary battery.

[0071] The cap down may be located below the safety vent. The cap down may have a first opening for exposing the protrusion of the safety vent and a second opening for gas discharge. An insulating member may be located between the safety vent and the cap down to insulate the safety vent from the cap down.

[0072] The subplate may be positioned below the cap down. The subplate may be fixed to the lower surface of the cap down to block the first opening of the cap down, and the protrusion of the safety vent may be fixed to the subplate. The first lead tab (35) drawn from the electrode assembly (30) may be fixed to the subplate. Thus, the cap up, safety vent, cap down, and subplate may be electrically connected to the first electrode (33) of the electrode assembly (30).

[0073] The insulating plate (37) may be positioned to be in contact with the electrode assembly (30) below the beading portion (43), and the insulating plate (37) may be provided with a tab opening for drawing out the first lead tab (35). The cap assembly (50), electrically connected to the first electrode (33) by the first lead tab (35), faces the electrode assembly (30) with the insulating plate (37) in between, and may be insulated from the electrode assembly (30) by the insulating plate (37). Meanwhile, another insulating plate (36) may be included for insulation between the electrode assembly (30) and the bottom portion (41) of the case.

[0075] In the following, to aid the understanding of those skilled in the art, the background of the proposed invention is explained, and embodiments of the invention are described.

[0076] Thermal runaway refers to a phenomenon in which chemical reactions within a cell proceed in a chain reaction due to abnormal heat accumulation and a rapid temperature rise inside the battery. For medium-to-large prismatic batteries used in electric vehicles, hybrid vehicles, and large-scale energy storage systems, preventing thermal propagation—where thermal runaway in a specific cell within a module or pack spreads to adjacent cells—has become a critical technical challenge. Thermal runaway is primarily caused by external impact, overcharging, internal short circuits, or manufacturing defects, and heat generation is accelerated through the decomposition of the electrolyte and oxidation reactions of the cathode material. Due to the characteristics of automotive batteries, if thermal runaway propagates to adjacent cells, there is a risk of it spreading to the entire module or pack, posing safety issues related to fire; furthermore, introducing excessive protective structures to prevent thermal runaway leads to a decrease in energy density.

[0077] To verify thermal runaway prevention technologies for medium-to-large prismatic batteries, various evaluation methods have been proposed at the cell, module, and pack levels. One method involves artificially inducing an internal short circuit by penetrating the battery cell from the outside with a metal nail; upon penetration, the internal electrodes come into direct contact, causing an electrical short circuit and triggering a rapid temperature rise. This method allows for the evaluation of the sensitivity to mechanical damage within the battery cell and the measurement of the impact of physical shock on battery thermal runaway. Additionally, a method has been proposed in which a heater (heating pad) is attached to the exterior of the battery cell to heat a specific location; upon reaching a certain temperature, the battery separator is damaged, thereby inducing an internal short circuit.

[0078] However, among the aforementioned methods, the external physical impact test (nail penetration test) is a method that causes a short circuit inside by physically damaging the metal outer casing (can) of the battery cell. This method has the problem that direct short circuits occur due to penetration, the internal structure is distorted, the normal internal resistance and electrical flow patterns are altered, and physical damage is applied. Furthermore, while actual thermal runaway generates uniform heat within the cell due to internal chemical reactions, penetration results in rapid heat generation only at specific points. Consequently, there is a limitation in accurately reproducing the actual heat propagation phenomenon, and there is a problem in that heat is concentrated in one direction due to physical damage, leading to asymmetric results.

[0079] The external heater heating method has limitations in accurately simulating actual heat propagation situations because it cannot completely block the temperature rise of cells even with insulation. In other words, even if insulation is applied to adjacent cells, perfect heat blockage is difficult, and heat transfer to adjacent cells occurs. Furthermore, since the heater method gradually raises the temperature from the outside, it faces the problem of being unable to perfectly simulate sudden runaway phenomena.

[0080] According to conventional technology, a method has been proposed to generate thermal runaway by heating a heater inserted into the cell. However, since a film-type heater must be inserted into the cell during cell manufacturing, followed by electrolyte injection and formation processes, there is a high risk of ignition during formation and difficulty in securing good quality cells.

[0081] The present invention is proposed to solve the aforementioned problems and aims to provide a heat propagation evaluation system and method capable of inducing thermal runaway without physical damage to the can and without additional heat transfer to adjacent cells.

[0082] FIG. 5 illustrates a heat propagation evaluation system according to an embodiment of the present invention.

[0083] A hole (510) is formed in the long side of the battery can, and a heater (520) is attached to the cell through the hole (510). The heater is configured in the form of a film and attached to the outer surface of the stack inside the cell. The hole (510) can be formed in various shapes, such as a circular or square shape, and its area is formed to be larger than the area of ​​the heater (520).

[0084] The portion (511) that was detached during hole processing is filled back into the space before detachment, and sealing is performed using a special adhesive or heat treatment method.

[0085] FIG. 6 illustrates the jig structure of a heat propagation evaluation system according to an embodiment of the present invention.

[0086] FIG. 6(a) shows a battery seated on a jig, and FIG. 6(b) shows a protruding structure (610) of the jig being fastened to correspond to a hole area (510) machined in the long side of a can to perform hole sealing.

[0087] A cylindrical protruding structure (610) is formed in the plate-shaped jig of a rectangular parallepiped so as to enable sealing of the hole area (510), and the height of the cylindrical structure is designed to be less than or equal to the height of the hole area.

[0088] As described above, when the hole area is formed in a rectangular shape, the shape of the protruding structure (610) of the jig is formed in a rectangular shape, and the height of the rectangular shape is designed to be less than or equal to the height of the hole area.

[0089] FIG. 7 illustrates a heat propagation evaluation method according to an embodiment of the present invention.

[0090] A heat propagation evaluation method according to an embodiment of the present invention includes the step of machining a hole in the long side portion of a rectangular cell (S710), the step of attaching a heater to the outer surface of a stack inside the cell (S720), and the step of performing sealing on the hole area (S730).

[0091] In step S710, a circular hole is machined into the long side of a rectangular cell without an internal heater. A hole is formed into the long side of the secondary battery can using laser cutting, CNC drilling, etc.

[0092] In step S720, a heater is attached to a preset area on the outer surface of a stack in which positive and negative electrode plates are stacked within the cell. The heater is attached in the form of a film and is connected to an external power source via wires to perform heating for a specific cell.

[0093] In step S730, the area that was detached during hole machining is filled back into the space before detachment, and sealing is performed using a special adhesive or heat treatment method.

[0094] According to another embodiment of the present invention, in step S730, a safety evaluation jig is coupled to the hole area to seal the hole and maintain airtightness inside the can. One side of the jig includes a cylinder corresponding to the size and shape of the hole, and a sealing material such as silicone or PTFE (Teflon) is applied to maintain a perfect seal. A temperature or pressure sensor is inserted inside the jig to enable real-time data collection during evaluation, and monitoring of the rise in internal pressure in the event of battery thermal runaway can be performed.

[0095] FIG. 8 is a block diagram showing a computer system for implementing a method according to an embodiment of the present invention.

[0096] Referring to FIG. 8, a computer system (1300) may include at least one of a processor (1310), memory (1330), an input interface device (1350), an output interface device (1360), and a storage device (1340) that communicate via a bus (1370). The computer system (1300) may also include a communication device (1320) coupled to a network. The processor (1310) may be a central processing unit (CPU) or a semiconductor device that executes instructions stored in memory (1330) or storage device (1340). Memory (1330) and storage device (1340) may include various forms of volatile or non-volatile storage media. For example, memory may include read-only memory (ROM) and random access memory (RAM). In the embodiments of this description, memory may be located inside or outside the processor, and memory may be connected to the processor through various known means. Memory is a volatile or non-volatile storage medium of various forms, and for example, memory may include read-only memory (ROM) or random access memory (RAM).

[0097] A thermal propagation evaluation system according to an embodiment of the present invention includes a memory (1330) storing a control program for simulating a battery cell thermal runaway phenomenon and a processor (1310) for executing the program, and the processor (1310)

[0098] Heat is applied using a heater attached to the hole, and the algorithm is executed to induce thermal runaway.

[0099] The height of the protruding structure is designed to be less than or equal to the height of the hole area.

[0100] Embodiments of the present invention may be implemented as a method implemented on a computer or as a non-transient computer-readable medium storing computer-executable instructions. In one embodiment, when executed by a processor, the computer-readable instructions may perform a method according to at least one aspect of the present description.

[0101] The communication device (1320) can transmit or receive wired or wireless signals.

[0102] In addition, the method according to an embodiment of the present invention may be implemented in the form of program instructions that can be executed through various computer means and may be recorded on a computer-readable medium.

[0103] The above computer-readable medium may include program instructions, data files, data structures, etc., either individually or in combination. The program instructions recorded on the computer-readable medium may be specially designed and configured for embodiments of the present invention, or they may be known and available to a person skilled in the art of computer software. The computer-readable recording medium may include a hardware device configured to store and execute program instructions. For example, the computer-readable recording medium may be magnetic media such as hard disks, floppy disks, and magnetic tapes; optical recording media such as CD-ROMs and DVDs; magneto-optical media such as floptical disks; ROM; RAM; flash memory, etc. The program instructions may include not only machine code, such as that generated by a compiler, but also high-level language code that can be executed by a computer through an interpreter, etc.

[0104] The following describes a material that can be used in a secondary battery according to the present invention.

[0105] As a positive electrode active material, a compound capable of reversible intercalation and deintercalation of lithium (a lithated intercalation compound) may be used. Specifically, one or more composite oxides of lithium and a metal selected from cobalt, manganese, nickel, and combinations thereof may be used.

[0106] The above composite oxide may be a lithium transition metal composite oxide, and specific examples include a lithium nickel-based oxide, a lithium cobalt-based oxide, a lithium manganese-based oxide, a lithium iron phosphate-based compound, a cobalt-free nickel-manganese-based oxide, or a combination thereof.

[0107] As an example, compounds represented by any one of the following chemical formulas may be used. LiaA1-bXbO2-cDc(0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05); LiaMn2-bXbO4-cDc(0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05); LiaNi1-b-cCobXcO2-αDα(0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α<2); LiaNi1-b-cMnbXcO2-αDα(0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α<2); LiaNibCocL1dGeO2(0.90≤a≤1.8, 0≤b≤0.9, 0≤c≤0.5, 0≤d≤0.5, 0≤e≤0.1); LiaNiGbO2(0.90≤a≤1.8, 0.001≤b≤0.1); LiaCoGbO2(0.90≤a≤1.8, 0.001≤b≤0.1); LiaMn1-bGbO2 (0.90≤a≤1.8, 0.001≤b≤0.1); LiaMn2GbO4 (0.90≤a≤1.8, 0.001≤b≤0.1); LiaMn1-gGgPO4(0.90≤a≤1.8, 0≤g≤0.5); Li(3-f)Fe2(PO4)3(0≤f≤2); LiaFePO4(0.90≤a≤1.8).

[0108] In the above chemical formula, A is Ni, Co, Mn, or a combination thereof; X is Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, a rare earth element, or a combination thereof; D is O, F, S, P, or a combination thereof; G is Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, or a combination thereof; and L1 is Mn, Al, or a combination thereof.

[0109] A positive electrode for a lithium secondary battery may include a current collector and a positive electrode active material layer formed on the current collector. The positive electrode active material layer may include a positive electrode active material and may further include a binder and / or a conductive material.

[0110] The content of the positive active material is 90% to 99.5% by weight with respect to 100% by weight of the positive active material layer, and the content of the binder and the conductive material may each be 0.5% to 5% by weight with respect to 100% by weight of the positive active material layer.

[0111] Al may be used as the current collector mentioned above, but is not limited thereto.

[0112] The negative electrode active material includes a material capable of reversibly intercalating / deintercalating lithium ions, lithium metal, an alloy of lithium metal, a material capable of doping and dedoping lithium, or a transition metal oxide.

[0113] A material capable of reversibly intercalating / deintercalating the above lithium ions may be a carbon-based negative electrode active material, such as crystalline carbon, amorphous carbon, or a combination thereof. Examples of the crystalline carbon include graphite, such as natural graphite or artificial graphite, and examples of the amorphous carbon include soft carbon or hard carbon, mesophase pitch carbide, calcined coke, etc.

[0114] As a material capable of doping and undoping the above lithium, a Si-based negative electrode active material or a Sn-based negative electrode active material may be used. The above Si-based negative electrode active material may be silicon, a silicon-carbon composite, SiOx (0 < x < 2), a Si-based alloy, or a combination thereof.

[0115] The silicon-carbon composite may be a composite of silicon and amorphous carbon. According to one embodiment, the silicon-carbon composite may be in the form of silicon particles and amorphous carbon coated on the surface of the silicon particles.

[0116] The silicon-carbon composite may further include crystalline carbon. For example, the silicon-carbon composite may include a core comprising crystalline carbon and silicon particles and an amorphous carbon coating layer located on the surface of the core.

[0117] A negative electrode for a lithium secondary battery comprises a current collector and a negative electrode active material layer located on the current collector. The negative electrode active material layer comprises a negative electrode active material and may further comprise a binder and / or a conductive material.

[0118] For example, the negative electrode active material layer may comprise 90% to 99% by weight of negative electrode active material, 0.5% to 5% by weight of binder, and 0% to 5% by weight of conductive material.

[0119] As the binder, a non-aqueous binder, an aqueous binder, a dry binder, or a combination thereof may be used. When an aqueous binder is used as the cathode binder, a cellulose-based compound capable of imparting viscosity may be further included.

[0120] As the above-mentioned cathode current collector, a material selected from copper foil, nickel foil, stainless steel foil, titanium foil, nickel foam, copper foam, a polymer substrate coated with a conductive metal, and combinations thereof may be used.

[0121] The electrolyte for lithium secondary batteries contains a non-aqueous organic solvent and a lithium salt.

[0122] The above-mentioned non-aqueous organic solvent serves as a medium through which ions involved in the electrochemical reaction of the battery can move.

[0123] The above-mentioned non-aqueous organic solvent may be a carbonate-based, ester-based, ether-based, ketone-based, or alcohol-based solvent, a non-protic solvent, or a combination thereof, and may be used alone or in a mixture of two or more types.

[0124] In addition, when using carbonate-based solvents, cyclic carbonates and chain carbonates can be mixed and used.

[0125] Depending on the type of lithium secondary battery, a separator may be present between the positive and negative electrodes. As such a separator, polyethylene, polypropylene, polyvinylidene fluoride, or a multilayer film of two or more layers thereof may be used.

[0126] The above separator may include a porous substrate and a coating layer comprising an organic material, an inorganic material, or a combination thereof located on one or both sides of the porous substrate.

[0127] The above organic material may include a polyvinylidene fluoride-based antibody or a (meth)acrylic-based polymer.

[0128] The above inorganic material may include inorganic particles selected from Al2O3, SiO2, TiO2, SnO2, CeO2, MgO, NiO, CaO, GaO, ZnO, ZrO2, Y2O3, SrTiO3, BaTiO3, Mg(OH)2, boehmite, and combinations thereof, but is not limited thereto.

[0129] The above organic and inorganic materials may exist mixed in a single coating layer, or may exist in a stacked form with a coating layer containing organic materials and a coating layer containing inorganic materials.

[0130] FIG. 9 is an exemplary diagram of a secondary battery module in which a secondary battery is arranged to apply an electrode assembly manufactured according to the present invention. A secondary battery module is manufactured by arranging and connecting a plurality of secondary battery cells in the transverse direction and / or longitudinal direction in accordance with the increase in capacity of secondary batteries for driving electric vehicles, etc. A plurality of secondary batteries are arranged in the space formed by a pair of opposing end plates (68a, 68b) and a pair of opposing side plates (69a, 69b). The arrangement of the secondary batteries can be designed in terms of the arrangement direction and number to obtain desired voltage and current specifications.

[0131] FIG. 10 is an example of a secondary battery pack (70) configured to apply the secondary battery module exemplified in FIG. 9 to an actual product (e.g., a car). The secondary battery pack can be manufactured by embedding a plurality of secondary battery modules in a pack housing designed to be mounted on an actual product. The pack housing may include a fastening part and an electrical output part necessary for mounting on the product. In FIG. 10, for convenience of illustration, the illustration of related elements such as a busbar for electrical connection of the secondary batteries, a cooling unit, and external terminals has been omitted.

[0132] A secondary battery pack may be mounted in a vehicle. The vehicle may be, for example, an electric vehicle, a hybrid vehicle, or a plug-in hybrid vehicle. The vehicle includes a four-wheel drive or two-wheel drive vehicle. FIG. 11 is a drawing for explaining a vehicle including a secondary battery pack exemplified in FIG. 10. FIG. 11 illustrates a secondary battery pack (70) according to an embodiment of the present invention mounted on the lower body of a vehicle (V). The vehicle (V) operates by receiving power from the secondary battery pack (70) according to an embodiment of the present invention.

[0133] Although the present invention has been described above with reference to limited embodiments and drawings, the present invention is not limited thereto, and it is obvious that various modifications and variations are possible within the scope of the technical spirit of the present invention and the equivalent scope of the claims described below by those skilled in the art to which the present invention belongs.

Claims

Claim 1 A heat propagation evaluation method performed by a heat propagation evaluation system, comprising the steps of: forming a hole in the long side portion of a battery can; attaching a heater through the area where the hole is formed; and performing sealing on the area where the hole is formed. Claim 2 A heat propagation evaluation method according to claim 1, wherein the step of machining a hole in the long side portion of the battery can is to machine a hole of a preset shape in the long side portion of a rectangular battery for vehicles. Claim 3 A heat propagation evaluation method according to claim 1, wherein the step of attaching the heater is to attach a film-type heater to the outer surface of a stack inside a cell. Claim 4 A heat propagation evaluation method according to claim 1, wherein the step of performing the sealing comprises placing the detached portion in the space prior to the detachment during the step of processing the hole, and performing the sealing using a special adhesive or heat treatment. Claim 5 A heat propagation evaluation method according to claim 1, wherein the step of performing the sealing is to perform sealing on the area where the hole is formed using a safety evaluation jig. Claim 6 A heat propagation evaluation method according to claim 5, wherein the jig includes a protruding structure corresponding to the size and shape of the area where the hole is formed. Claim 7 A heat propagation evaluation method according to claim 6, characterized in that the height of the protruding structure is less than or equal to the height of the area where the hole is formed. Claim 8 A heat propagation evaluation method according to claim 6, wherein at least one of a temperature sensor and a pressure sensor is disposed inside the protruding structure. Claim 9 A thermal propagation evaluation system comprising: a memory storing a control program for simulating a battery cell thermal runaway phenomenon; and a processor for executing said program, wherein the processor transmits a control command to perform an algorithm to apply heat using a heater attached to a hole and thereby cause thermal runaway to occur. Claim 10 A heat propagation evaluation system according to claim 9, wherein the height of the protruding structure is designed to be less than or equal to the height of the area where the hole is formed. Claim 11 A heat propagation evaluation device comprising: a heater that is inserted into and attached to the interior through a hole area formed in a battery can; and a sealing member that performs sealing of the hole area. Claim 12 A heat propagation evaluation device according to claim 11, wherein the heater is attached in a film type to a predetermined area among the outer surface areas of the cell stack through the hole area formed in the long side of the battery can. Claim 13 A heat propagation evaluation device according to claim 12, wherein the sealing member is a protruding structure disposed on one surface of a safety evaluation jig, the protruding structure is formed to correspond to the size and shape of the hole area, and the height of the protruding structure is formed to be less than or equal to the height of the hole area.

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