Secondary battery module with improved temperature stability inside the module

Abstract

The present invention relates to a heat absorption pack for a secondary battery module and a secondary battery module including the same. The heat absorption pack includes a highly absorbent matrix impregnated with water inside a pouch, and a heat dispersion substrate is inserted between the highly absorbent matrix and the pouch. As a result, the heat absorption pack can absorb a large amount of heat from the surroundings when heat is generated inside the module, and when the heat absorption pack is provided in a secondary battery module, the surrounding temperature of the secondary battery can be prevented from changing suddenly. In addition, the highly absorbent matrix is ​​uniformly exposed to the surrounding thermal energy, and damage to the heat absorption pack due to heat generation inside the module can be prevented. Therefore, the heat absorption pack having the above configuration can more stably control the temperature inside the module, thereby improving the performance and stability of the secondary battery according to the surrounding temperature.

Description

[Technical Field]

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0132265, dated October 14, 2022, and all contents disclosed in the documents of this Korean patent application are incorporated herein by reference.

[0002] The present invention relates to a heat-absorbing pack for a secondary battery module that can uniformly absorb thermal energy when the temperature inside the secondary battery module rises, thereby preventing large changes in the internal temperature, and a secondary battery module including the same that has improved stability against temperature changes inside the module. [Background technology]

[0003] BACKGROUND ART In recent years, secondary batteries have been widely used not only in small devices such as portable electronic devices but also in medium to large devices such as battery packs for hybrid cars and electric cars or power storage devices.

[0004] The secondary battery includes an electrode assembly including a positive electrode, a negative electrode, and a separator, an electrolyte, and a multilayer exterior material that protects the electrode assembly and the electrolyte. The secondary battery may be used in the form of a battery module in which multiple cells are mounted.

[0005] However, such secondary batteries are sensitive to changes in ambient temperature, which can significantly affect their electrical performance and safety.

[0006] For example, an electrode assembly included in a secondary battery generates heat during charging and discharging. This heat not only reduces the performance of the secondary battery cell, but also increases the temperature of the secondary battery cell itself, which can lead to cell explosion. The cell explosion can cause other surrounding secondary battery cells to experience high temperatures and pressures, leading to a chain reaction of secondary battery cell explosions.

[0007] Thermal runaway prevention sheet technologies have been developed to suppress heat transfer to adjacent cells during thermal runaway in secondary batteries. For example, a technology has been developed that improves heat transfer efficiency by installing a cartridge containing a thermally conductive additive inside a battery module. However, this conventional technology is designed to cool heat generated during battery operation and has a problem of not functioning properly in thermal runaway situations such as cell explosion. Additionally, a technology has been developed that includes a cooling member that absorbs heat generated within a secondary battery module to lower the ambient temperature. However, actual thermal runaway is often caused by heat generated by a specific cell installed in the module. In this case, the cooling member has difficulty uniformly absorbing the heat generated by the cells, which can lead to damage to the cooling member during the heat absorption process, resulting in limitations in the cooling member's ability to sufficiently absorb internal heat.

[0008] Therefore, in a secondary battery module including a secondary battery, when the temperature inside the module, i.e., the temperature around the secondary battery, is in a high temperature / heat generating condition that induces thermal runaway of the battery, there is a need to develop a technology that can effectively and uniformly absorb the ambient temperature and prevent the temperature inside the module from rising suddenly. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Korean Patent Publication No. 10-2015-0000725 Summary of the Invention [Problem to be solved by the invention]

[0010] Therefore, an object of the present invention is to provide a technology that can suppress abrupt temperature changes inside a secondary battery module by uniformly absorbing heat generated when the module is heated. [Means for solving the problem]

[0011] To solve the above problem, In one embodiment, the present invention comprises: a highly absorbent matrix; a heat dissipation substrate disposed on at least one surface of the highly absorbent matrix; a pouch into which the high-absorbency matrix having the heat-dispersing substrate disposed thereon is inserted; The highly absorbent matrix is ​​impregnated with water, The heat dissipating substrate provides a heat absorbing pack for a secondary battery module, which includes a metal sheet that satisfies the following formula 1 at 10 to 500:

[0012] [Formula 1] T pack / T sheet

[0013] In the above formula 1, T pack represents the average thickness of the endothermic pack (unit: μm), T sheet represents the average thickness of the metal sheet (unit: μm).

[0014] In this case, the metal sheet may have an average thickness of 5 μm to 100 μm and may contain a metal having a thermal conductivity of 50 kcal / ° C. or more.

[0015] The heat dissipation substrate can cover 70% or more of the surface of the highly absorbent matrix.

[0016] Furthermore, the above-mentioned superabsorbent matrix may have a heat dispersing substrate disposed on its surface, so that the area in direct contact with the pouch is 30% or less of the total area of ​​the superabsorbent matrix.

[0017] The superabsorbent matrix may also be in the form of a superabsorbent polymer (SAP) or a superabsorbent fiber (SAF).

[0018] The superabsorbent matrix may also comprise one or more resins selected from polyacrylic acid, polyacrylates, polyacrylate graft polymers, starch, crosslinked carboxymethylated cellulose, acrylic acid copolymers, hydrolyzed starch-acrylonitrile graft copolymers, starch-acrylic acid graft copolymers, saponified vinyl acetate-acrylic acid ester copolymers, hydrolyzed acrylonitrile copolymers, hydrolyzed acrylamide copolymers, ethylene-maleic anhydride copolymers, isobutylene-maleic anhydride copolymers, polyvinyl sulfonic acid, polyvinyl phosphonic acid, polyvinyl phosphoric acid, polyvinyl sulfate, sulfonated polystyrene, polyvinylamine, polydialkylaminoalkyl(meth)acrylamide, polyethyleneimine, polyallylamine, polyallylguanidine, polydimethyldiallylammonium hydroxide, polystyrene derivatives, guanidine-modified polystyrene, poly(meth)acrylamide, polyvinyl guanidine, and mixtures thereof.

[0019] The highly absorbent matrix may also optionally contain a thermally conductive filler therein along with the resin.

[0020] Such highly absorbent matrices can contain between 10 g / g and 500 g / g of water.

[0021] Furthermore, in one embodiment, the present invention provides a housing member; a plurality of battery cells inserted into the housing member; There is also provided a secondary battery module including the heat-absorbing pack of the present invention that absorbs heat generated in the plurality of battery cells.

[0022] Here, the plurality of battery cells may be aligned in n rows (where n≧2), and in this case, the heat absorption pack may be disposed between the rows of the arranged battery cells, and / or may be disposed in the space between the outer surface of the row of the arranged battery cells and the housing member. [Effects of the Invention]

[0023] The heat absorption pack for a secondary battery module according to the present invention includes a water-impregnated high-absorbency matrix within a pouch, and a heat dissipation substrate is inserted between the high-absorbency matrix and the pouch. This structure allows the pack to absorb a large amount of heat from the surrounding area when heat is generated within the module. Therefore, when the pack is installed in a secondary battery module, it can prevent sudden changes in the ambient temperature of the secondary battery. Furthermore, the high-absorbency matrix is ​​uniformly exposed to ambient thermal energy, preventing damage to the heat absorption pack due to heat generated within the module. Therefore, the heat absorption pack having the above structure can more stably control the temperature within the module, thereby improving the performance and stability of the secondary battery according to the ambient temperature. [Brief explanation of the drawings]

[0024] [Figure 1] 1 is a perspective view showing a structure of a secondary battery module according to the present invention; [Figure 2] 10 is a photographed image of the heat absorption pack of the embodiment disassembled after the internal heating of the secondary battery module. [Figure 3] 10 is a photographed image of a comparative example of a heat absorption pack that has been disassembled after the internal heating of a secondary battery module. DETAILED DESCRIPTION OF THE INVENTION

[0025] Because the present invention is susceptible to various modifications and may have various embodiments, specific embodiments are described in detail in the detailed description.

[0026] However, this is not intended to limit the invention to any particular embodiment, but rather to be understood as including all modifications, equivalents, or alternatives falling within the spirit and scope of the invention.

[0027] In the present invention, terms such as "comprise" and "have" are intended to specify the presence of features, numbers, steps, operations, components, parts or combinations thereof described in the specification, and may be understood as not precluding the presence or possibility of addition of one or more other features, numbers, steps, operations, components, parts or combinations thereof.

[0028] Furthermore, in the present invention, when a layer, film, region, plate, or other portion is described as being "on" another portion, this includes not only the case where it is "directly on" the other portion, but also the case where there is another portion therebetween. Conversely, when a layer, film, region, plate, or other portion is described as being "under" the other portion, this includes not only the case where it is "directly under" the other portion, but also the case where there is another portion therebetween. Furthermore, in this application, being "located on" can include not only the case where it is located at the top, but also the case where it is located at the bottom.

[0029] The present invention will now be described in more detail.

[0030] <Heat absorption pack for secondary batteries> In one embodiment, the present invention comprises: a highly absorbent matrix; a heat dissipation substrate disposed on at least one surface of the highly absorbent matrix; and a pouch into which the highly absorbent matrix having the heat dissipating substrate disposed thereon is inserted.

[0031] The heat-absorbing pack according to the present invention is a component inserted into the interior of a secondary battery module, and has a structure in which a highly absorbent matrix impregnated with water is inserted into a pouch.

[0032] The high-absorbency matrix is ​​impregnated with water, and thus can absorb a large amount of thermal energy depending on the temperature conditions around the endothermic pack, i.e., the internal temperature conditions of the secondary battery module to which the endothermic pack is attached. Specifically, the water is impregnated within the high-absorbency matrix, and when the temperature outside the pouch rises, it vaporizes and separates from the high-absorbency matrix. The water requires a large amount of heat to vaporize, and absorbs the heat around the pouch to meet this requirement. This prevents a sudden rise in the internal temperature when heat is generated inside the module.

[0033] Here, in the heat-absorbing pack according to the present invention, a heat-dispersing substrate can be disposed on at least one surface of the highly absorbent matrix so that the water impregnated in the highly absorbent matrix can uniformly absorb heat.

[0034] The heat dissipation substrate can play a role in preventing the generated heat from concentrating in one part of the endothermic pack and damaging the endothermic pack by uniformly transferring the heat outside the pouch to the highly absorbent matrix.

[0035] For this purpose, the heat dissipating substrate may include a metal sheet with high thermal conductivity, and the metal sheet may include a metal having a thermal conductivity of 50 kcal / °C or more. More specifically, the metal sheet may include a metal having a thermal conductivity of 70 kcal / °C or more, 80 kcal / °C or more, 90 kcal / °C or more, 100 kcal / °C or more, 50 kcal / °C to 400 kcal / °C, 70 kcal / °C to 370 kcal / °C, 70 kcal / °C to 150 kcal / °C, 100 kcal / °C to 370 kcal / °C, 150 kcal / °C to 200 kcal / °C, or 250 kcal / °C to 350 kcal / °C.

[0036] As an example, the metal sheet may include aluminum having a thermal conductivity of 196±3 kcal / °C, tungsten having a thermal conductivity of 170±3 kcal / °C, copper having a thermal conductivity of 320±3 kcal / °C, nickel having a thermal conductivity of 77±3 kcal / °C, or the like, either alone or in combination.

[0037] Furthermore, the heat-dissipating substrate includes a metal sheet with high thermal conductivity. However, the heat transferred to the highly absorbent matrix through the metal sheet must be dispersed over the entire surface of the highly absorbent matrix, which can be highly dependent on the thickness of the metal sheet. Therefore, the heat-dissipating substrate may have a predetermined thickness to transfer heat from the periphery of the pouch (i.e., outside the pouch) to the highly absorbent matrix with high efficiency and in a more uniformly dispersed manner. Furthermore, a certain thickness requirement for the heat-dissipating pack may be met, taking into consideration the reduction in the energy density of the secondary battery module due to the heat-dissipating pack and the thermal conduction efficiency of the metal sheet itself included in the heat-dissipating substrate.

[0038] For example, the heat dispersing substrate may have an average thickness of 5 μm to 100 μm, and the following formula 1, which indicates the ratio of the average thickness of the heat absorption pack including the heat dispersing substrate to the average thickness of the heat dispersing substrate, may be 10 to 500.

[0039] [Formula 1] T pack / T sheet

[0040] In the above formula 1, T pack represents the average thickness of the endothermic pack (unit: μm), T sheet represents the average thickness of the metal sheet (unit: μm).

[0041] Specifically, the above formula (1) refers to the ratio between the average thickness of the heat-absorbing pack and the average thickness of the heat-dispersing substrate. By ensuring that this ratio satisfies a predetermined range, the present invention can prevent a reduction in the energy density of the secondary battery module and efficiently disperse and absorb thermal energy into the heat-absorbing pack without damaging the heat-absorbing pack when high temperatures are generated inside. To this end, the heat-dispersing substrate can satisfy the formula (1) at a value between 10 and 500, specifically, 10 to 400, 10 to 300, 10 to 200, 10 to 100, 10 to 50, 100 to 300, or 100 to 200. By satisfying the formula (1) at 10 or more, the content of the high-absorbency matrix can be reduced, preventing a decrease in heat absorption efficiency. By satisfying the formula (1) at 500 or less, the thin thickness of the heat-dispersing substrate can prevent heat around the pouch from being uniformly dispersed in the high-absorbency matrix, preventing damage to the heat-dispersing pack.

[0042] The heat dissipation substrate may have an average thickness of 5 μm to 100 μm, more specifically 5 μm to 75 μm, 5 μm to 50 μm, 5 μm to 30 μm, 10 μm to 30 μm, or 15 μm to 25 μm.

[0043] By adjusting the average thickness of the heat dispersing substrate within the above range, the present invention can prevent the endothermic pack from being damaged during heat absorption due to a thickness of less than 5 μm, which prevents the heat around the pouch from being uniformly transferred to the highly water-absorbent matrix, while preventing the thermal conductivity of the heat dispersing substrate from being reduced due to an excessive thickness of more than 100 μm.

[0044] Furthermore, in order to more uniformly absorb heat around the pouch, the highly absorbent matrix may have a heat dispersing substrate disposed on the surface that directly contacts the pouch so as to fill a predetermined area ratio.

[0045] Specifically, the heat-dispersing substrate may be disposed so as to cover 70% or more of the entire surface of the superabsorbent matrix, and more specifically, so as to cover 75% or more, 80% or more, 85% or more, or 90% or more of the entire surface of the superabsorbent matrix. In some cases, the heat-dispersing substrate may be disposed over the entire surface of the superabsorbent matrix, and the area in direct contact between the superabsorbent matrix and the pouch may be 0%. By adjusting the area ratio of the heat-dispersing substrate covering the surface of the superabsorbent matrix within the above range, the present invention can allow heat around the pouch to be more uniformly distributed to the superabsorbent matrix.

[0046] Meanwhile, as described above, when the endothermic pack is exposed to high temperature conditions, the water impregnated in the highly absorbent matrix may evaporate and separate, and as a result, the pouch into which the highly absorbent matrix is ​​inserted may have an expanded form.

[0047] The superabsorbent matrix may contain a superabsorbent polymer (SAP) or a superabsorbent fiber (SAF) to efficiently absorb water. The SAP and SAF may be differentiated by their shapes. For example, the SAP may be powder-shaped, while the SAF may be linear.

[0048] The superabsorbent resin (SAP) and the superabsorbent fiber (SAF) may be composed of the same or different components. Specifically, the superabsorbent matrix may be at least one selected from the group consisting of polyacrylic acid, polyacrylates, polyacrylate graft polymers, starch, crosslinked carboxymethyl cellulose, acrylic acid copolymers, hydrolyzed starch-acrylonitrile graft copolymers, starch-acrylic acid graft copolymers, saponified vinyl acetate-acrylic acid ester copolymers, hydrolyzed acrylonitrile copolymers, hydrolyzed acrylamide copolymers, ethylene-maleic anhydride copolymers, isobutylene-maleic anhydride copolymers, polyvinyl sulfonic acid, polyvinyl phosphonic acid, polyvinyl phosphoric acid, polyvinyl sulfate, sulfonated polystyrene, polyvinylamine, polydialkylaminoalkyl(meth)acrylamide, polyethyleneimine, polyallylamine, polyallylguanidine, polydimethyldiallylammonium hydroxide, polystyrene derivatives, guanidine-modified polystyrene, poly(meth)acrylamide, polyvinyl guanidine, and mixtures thereof.

[0049] As an example, the superabsorbent matrix may include, but is not limited to, one or more selected from the group consisting of cross-linked polyacrylates, cross-linked polyacrylic acids, and cross-linked acrylic acid copolymers.

[0050] The type of acrylic acid copolymer used as the superabsorbent matrix in the present invention is not particularly limited, but is preferably a copolymer containing an acrylic acid monomer and at least one comonomer selected from maleic acid, itaconic acid, acrylamide, 2-acrylamido-2-methylpropanesulfonic acid, 2-(meth)acryloylethanesulfonic acid, 2-hydroxyethyl (meth)acrylate, and styrenesulfonic acid.

[0051] The above component is a material having a network structure with hydrophilic functional groups and can absorb water with high efficiency, so that the heat absorption or heat generation effect of the heat absorption pack can be realized uniformly.

[0052] The high-absorbency matrix may also have a water absorption capacity that satisfies a certain range. Specifically, the high-absorbency matrix may have a water absorption capacity of 10 g / g to 500 g / g, more specifically 50 g / g to 200 g / g, but is not limited thereto. This means that the high-absorbency matrix can absorb 10 g to 500 g, preferably 50 g to 200 g, of water per gram of the high-absorbency matrix. The higher the water absorption capacity of the high-absorbency matrix, the longer the cooling effect can last. However, if the water absorption capacity exceeds 500 g / g, the fluidity of the high-absorbency matrix increases, making it difficult to maintain its shape and preventing effective cooling. Furthermore, if the water absorption capacity of the high-absorbency matrix is ​​less than 10 g / g, the amount of heat absorbed in response to the temperature outside the pouch will be significantly reduced, resulting in a low and inefficient effect of suppressing sudden changes in the temperature inside the module.

[0053] The highly absorbent matrix may further include a thermally conductive filler therein to better transfer heat to the water impregnated within the matrix.

[0054] The thermally conductive filler can be used without limitation as long as it has excellent heat transfer properties, and specifically, one or more types selected from inorganic oxide fillers, metal hydroxide fillers, inorganic carbide fillers, nitride fillers, metal fillers, and carbon fillers can be used.

[0055] Examples of the inorganic oxide filler include aluminum oxide, magnesium oxide, zinc oxide, and silicon oxide. Examples of the metal hydroxide filler include aluminum hydroxide and magnesium hydroxide. Examples of the inorganic carbide filler include silicon carbide. Examples of the nitride filler include aluminum nitride, boron nitride, and silicon nitride. Examples of the metal filler include silver, copper, zinc, iron, aluminum, nickel, tin, and alloys thereof. Examples of the carbon filler include carbon and graphite.

[0056] Furthermore, the shape of the thermally conductive filler is not particularly limited, but it may have a spherical shape with a high specific surface area to effectively transfer heat inside the highly absorbent matrix, or it may have a needle-like or fibrous shape to form a thermal network with adjacent thermally conductive fillers.

[0057] Furthermore, the pouch may be applied without any particular limitation as long as it can efficiently transfer external heat to the highly absorbent matrix inserted therein. For example, the pouch may be formed of a metal layer, and the inner surface of the metal layer may include an inner layer containing a cross-linked polyolefin resin.

[0058] The metal layer may include an aluminum layer that can efficiently transfer heat from the outside of the heat-absorbing pack to the inside, has a certain level of strength, and is resistant to external forces.

[0059] The inner layer may be located on the inner surface of the metal layer and function to prevent the water impregnated in the highly absorbent matrix from reacting with the metal layer of the pouch. To this end, the inner layer may include a crosslinked polyolefin resin. Crosslinked polyolefin resins have low hygroscopicity and can inhibit the penetration of water impregnated in the highly absorbent matrix, thereby preventing the inner layer from swelling or erosion. The polyolefin resin may have a crosslinking degree of 10 to 70%, specifically 30 to 50%. The polyolefin resin may be at least one selected from polypropylene (PP) and polyethylene (PE). The crosslinked polyolefin resin may specifically include crosslinked polyethylene, crosslinked polypropylene, or a mixture thereof, more specifically crosslinked polypropylene.

[0060] Furthermore, the endothermic pack may have a thickness that satisfies a certain requirement for effectively controlling temperature changes within the module. Specifically, the endothermic pack may have a thickness of 0.1 mm to 50 mm, more specifically, 0.1 mm to 30 mm, 0.1 mm to 15 mm, 0.1 mm to 10 mm, 1 mm to 20 mm, 5 mm to 10 mm, 10 mm to 20 mm, or 1 mm to 5 mm.

[0061] In the present invention, by adjusting the thickness of the endothermic pack within the above range, if the thickness is less than 0.1 mm, the thickness of the endothermic pack is too thin, which will result in insufficient flow of thermal energy around the endothermic pack, causing the temperature inside the module to change rapidly; if the thickness exceeds 50 mm, the thickness of the battery module will increase, which may significantly reduce the energy density.

[0062] The heat absorption pack according to the present invention, having the above-described configuration, can not only absorb a large amount of heat from the surrounding area when heat is generated inside the module, but also uniformly distribute the heat to the highly absorbent matrix, thereby preventing damage to the heat absorption pack due to heat generated inside the module. Therefore, when the heat absorption pack is installed in a secondary battery module, it can prevent sudden changes in the ambient temperature of the secondary battery, thereby improving the performance and stability of the secondary battery according to the ambient temperature.

[0063] <Secondary battery module> Furthermore, in one embodiment, the present invention provides A secondary battery module is provided, which includes a secondary battery and the above-described heat-absorbing pack for a secondary battery according to the present invention.

[0064] FIG. 1 is a perspective view showing the structure of a secondary battery module 1 according to the present invention, which will be described in more detail with reference to FIG.

[0065] A secondary battery module 1 according to the present invention includes a housing member 10, a plurality of battery cells 20 inserted into the housing member, and a heat absorption pack 30 that absorbs heat generated by the plurality of battery cells.

[0066] The secondary battery module 1 according to the present invention includes a plurality of battery cells 20, and is equipped with the heat absorption pack 30 according to the present invention described above together with these battery cells, which can prevent the temperature inside the module from rising suddenly, thereby providing the advantage of excellent stability against the temperature of the battery cells 20.

[0067] Here, the housing member 10 serves as a body of the battery module that accommodates the plurality of battery cells 20. The housing member 10 is a member that accommodates the plurality of battery cells 20, and protects the battery cells 20 while transmitting electrical energy generated by the battery cells 20 to the outside.

[0068] For this purpose, the housing member 10 may be composed of a bottom member 11 and side wall members 12. The bottom member 11 seats the plurality of battery cells 20 and supports the seated plurality of battery cells 20. In addition, a heat sink 40 may be disposed between the bottom member 11 and the battery cells 20, and the heat sink 40 may be configured to transfer heat generated in the battery cells 20 to the bottom member 11, and the bottom member 11 may be configured to transfer the heat transferred from the heat sink 40 to the outside for cooling.

[0069] Furthermore, the side wall member 12 forms the side of the housing member 10 and can also discharge heat generated in the battery cells 20 to the outside.

[0070] The housing member 10 may further include a cover member 13 provided on the upper end of the side wall member 12 to protect the upper end of the battery cell 20. In addition, a gas venting member 17 may be provided between the cover member 13 and the upper end of the battery cell 20 to allow gas generated in the battery cell 20 during charging and discharging to be discharged to the outside.

[0071] The housing member 10 may also include a front member 14 and a rear member 15 adjacent to the side wall member 12, and may thereby be configured in a form that surrounds the sides of the plurality of battery cells 20.

[0072] Furthermore, the housing member 10 may include additional components such as bus bar members (not shown) that electrically connect the battery cells 20 to the outside.

[0073] Meanwhile, the type of the battery cell 20 is not particularly limited as long as it has a shape that can be applied as a lithium secondary battery, and specifically, the battery cell 20 may have a shape such as a prismatic shape, a pouch shape, a cylindrical shape, etc. As one example, the battery cell 20 may be a prismatic or pouch-shaped lithium secondary battery.

[0074] The battery cells 20 may be inserted into the housing member 10 and aligned in n rows (where n≧2) so as to face the sidewall members 12 of the housing member 10. Specifically, the battery cells 20 may be aligned in two or more rows, three or more rows, or two to four rows so as to face the sidewall members 12.

[0075] The heat absorption packs 30 may be disposed adjacent to the aligned battery cells 20. As one example, the heat absorption packs 30a may be disposed on the outer surfaces of the aligned battery cells 20, i.e., in the spaces between the housing member 10 and the battery cells 20.

[0076] As another example, heat absorption packs 30b may be inserted between battery cells 20. Specifically, the heat absorption packs 30b may be disposed between individual battery cells 20 constituting one row, and in some cases, may be disposed between the first row 21a and the second row 21b of batteries arranged as shown in FIG.

[0077] In this way, by arranging the heat absorption pack 30 in a position adjacent to the battery cell 20, if heat is generated in the battery cell 20, the heat can be absorbed immediately, thereby preventing sudden temperature changes inside the module.

[0078] The present invention will be described in more detail below with reference to examples and experimental examples.

[0079] However, the following examples and experimental examples are merely illustrative of the present invention, and the content of the present invention is not limited to the following examples and experimental examples.

[0080] <Examples 1 to 4 and Comparative Examples 1 to 3. Production of Endothermic Packs> 10 g of water was impregnated into 1 g of the highly absorbent fiber (component: acrylic acid copolymer). Then, aluminum sheets were placed on both sides of the highly absorbent fiber as heat dissipation sheets.

[0081] Separately, an aluminum pouch measuring 10 cm wide and 35 cm long was prepared, which contained an aluminum layer and a polyethylene (PE) layer with a cross-linking degree of 40±2% inside the aluminum layer. The highly absorbent matrix with aluminum (Al) sheets on both sides was inserted into the prepared aluminum pouch, and after creating a vacuum inside, the pouch's opening was sealed to produce an endothermic pack.

[0082] At this time, (1) the average thickness of the metal sheet, (2) the ratio of the average thickness of the heat absorption pack to the average thickness of the metal sheet (T pack / T sheet ) and (3) the percentage of the total area of ​​the superabsorbent fiber covered by the metal sheet (i.e., area ratio) are shown in Table 1 below.

[0083] [Table 1]

[0084] <Experimental example> In order to evaluate the temperature regulation effect inside the secondary battery module by the heat absorption pack according to the present invention, the following experiment was carried out.

[0085] a) Manufacturing of secondary battery modules In this case, as shown in FIG. 1, the secondary battery module was constructed such that 10 secondary battery cells per row were inserted into a housing member in two rows, and the heat absorption packs manufactured in the examples and comparative examples were disposed between the outer surfaces of the battery cells and each row.

[0086] In addition, in order to adjust the temperature inside the secondary battery module for the experiment, a heating pad, which is a heating means, was installed instead of a heat sink at the bottom of any one of the two rows into which secondary battery cells were inserted, and temperature sensors were installed on one of the sides and the top of the module.

[0087] Additionally, 40 positive and negative electrodes were prepared for the battery cells to be inserted into the module, and 120 porous polyethylene separators (9.5cm wide x 34.5cm long, average thickness: approximately 20μm) wider than the positive and negative electrodes were prepared as separators. Next, 40 separator-negative electrode-separator-positive electrode-separator stack unit cells were stacked to create a rectangular shape measuring 10cm wide x 35cm long x 1.6cm thick. The electrolyte injected into each battery cell was a liquid electrolyte consisting of an organic solvent mixture of ethylene carbonate (EC) and ethyl methyl carbonate (EMC) in a volume ratio of 3:7, to which LiPF6 was added at a concentration of 1M as a lithium salt. Each battery cell was inserted fully charged into the housing member.

[0088] B) Safety evaluation under high temperature conditions To evaluate safety under high-temperature conditions, the internal temperature of the secondary battery module was increased at a rate of 5°C / min for 30 minutes using a heating pad attached to the module. (a) After heating the inside of the module for 30 minutes, the internal temperature was measured using two temperature sensors attached to the module, and the average temperature was calculated as the internal module temperature. (b) After the temperature measurement was completed, the heating pad was stopped, the inside of the module was allowed to cool to room temperature, and the endothermic pack attached to the module was disassembled and the superabsorbent fiber inserted in the pouch was visually evaluated for damage. The results are shown in Table 2 below and Figures 2 and 3. Damage to the superabsorbent fiber was indicated by a circle (◯) or an × (×).

[0089] [Table 2]

[0090] As shown in Table 2 above, it can be seen that the heat-absorbing pack of the embodiment according to the present invention stably suppresses a sudden temperature rise inside the battery module.

[0091] Specifically, it was confirmed that the endothermic pack of the example absorbed the heat as internal heating by the heating pad installed inside the module progressed, maintaining the temperature inside the module below approximately 130° C. Furthermore, as shown in Figure 2, it was confirmed that the endothermic pack of the example absorbed the heat evenly around the pouch, preventing internal damage to the superabsorbent fiber.

[0092] In contrast, the heat absorption pack of the comparative example did not have a metal sheet, i.e., an aluminum (Al) sheet, placed between the pouch and the superabsorbent fiber, or did not meet the thickness requirements of the present invention. As a result, not only were the heat energy inside the module not sufficiently absorbed, but as shown in Figure 3, internal damage occurred to both the superabsorbent fiber and the pouch during heat absorption, and the heat absorption of the heat absorption pack was not stable.

[0093] From these results, it can be seen that the endothermic pack of the present invention can absorb a large amount of heat inside the module under high temperature conditions, prevent the temperature inside the module from changing suddenly, and absorb the heat evenly inside the endothermic pack, preventing damage to the endothermic pack during the heat absorption process, thereby enabling more stable control of the temperature inside the module.

[0094] Although the present invention has been described above with reference to preferred embodiments, it will be understood that a person skilled in the art or having ordinary knowledge in the art can make various modifications and changes to the present invention without departing from the spirit and technical scope of the present invention as set forth in the claims.

[0095] Therefore, the technical scope of the present invention is not limited to the content described in the Summary of the Invention of the specification, but is defined by the claims. [Explanation of symbols]

[0096] 1: Secondary battery module 10: Housing material 11:Bottom member 12: Side wall member 13: Cover material 14: Front member 15: Rear member 16: Partition wall material 17: Gas venting components 20: Battery cell 21: A row of aligned battery cells 21a: First row of aligned battery cells 21b: Second row of aligned battery cells 30: Heat absorption pack 30a: Heat-absorbing pack placed on the outer surface of the battery cell 30b: Heat-absorbing packs arranged between multiple rows of aligned battery cells 40: Heat sink

Claims

1. a highly absorbent matrix; a heat dissipation substrate disposed on at least one surface of the highly absorbent matrix; a pouch into which the high-absorbency matrix having the heat-dispersing substrate disposed thereon is inserted; the highly absorbent matrix is ​​impregnated with water; The heat dissipating substrate comprises a metal sheet that satisfies the following formula 1 at 10 to 500: [Formula 1] T ｐａｃｋ / T ｓｈｅｅｔ In the formula 1, T ｐａｃｋ represents the average thickness of the endothermic pack (unit: μm), T ｓｈｅｅｔ represents the average thickness of the metal sheet (unit: μm).

2. 2. The heat-absorbing pack for a secondary battery module according to claim 1, wherein the metal sheet has an average thickness of 5 μm to 100 μm.

3. 3. The heat-absorbing pack for a secondary battery module according to claim 1, wherein the metal sheet contains a metal having a thermal conductivity of 50 kcal / °C or more.

4. 2. The heat-absorbing pack for a secondary battery module according to claim 1, wherein the heat-dispersing substrate covers 70% or more of the surface of the highly absorbent matrix.

5. 2. The heat-absorbing pack for a secondary battery module according to claim 1, wherein the highly absorbent matrix is ​​a highly absorbent polymer (SAP) or a highly absorbent fiber (SAF).

6. 2. The heat-absorbing pack for a secondary battery module according to claim 1, wherein the highly absorbent matrix comprises one or more resins selected from the group consisting of polyacrylic acid, polyacrylates, polyacrylate graft polymers, starch, crosslinked carboxymethylated cellulose, acrylic acid copolymers, hydrolyzed starch-acrylonitrile graft copolymers, starch-acrylic acid graft copolymers, saponified vinyl acetate-acrylic acid ester copolymers, hydrolyzed acrylonitrile copolymers, hydrolyzed acrylamide copolymers, ethylene-maleic anhydride copolymers, isobutylene-maleic anhydride copolymers, polyvinyl sulfonic acid, polyvinyl phosphonic acid, polyvinyl phosphoric acid, polyvinyl sulfate, sulfonated polystyrene, polyvinylamine, polydialkylaminoalkyl(meth)acrylamide, polyethyleneimine, polyallylamine, polyallylguanidine, polydimethyldiallylammonium hydroxide, quaternized polystyrene derivatives, guanidine-modified polystyrene, quaternized poly(meth)acrylamide, polyvinyl guanidine, and mixtures thereof.

7. 2. The heat-absorbing pack for a secondary battery module according to claim 1, wherein the highly absorbent matrix further contains a thermally conductive filler therein.

8. 2. The heat-absorbing pack for a secondary battery module according to claim 1, wherein the highly absorbent matrix contains 10 g / g to 500 g / g of water.

9. a housing member; a plurality of battery cells inserted into the housing member; A secondary battery module comprising the heat absorption pack according to claim 1 for absorbing heat generated by the plurality of battery cells.

10. 10. The secondary battery module according to claim 9, wherein the plurality of battery cells are aligned and arranged in n rows (where n≧2), and heat absorption packs are arranged between the rows of arranged battery cells.

11. 10. The secondary battery module according to claim 9, wherein the plurality of battery cells are aligned in n rows (where n≧2), and a heat absorption pack is disposed in a space between an outer surface of the row of arranged battery cells and the housing member.

Images