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 said Korean patent application are incorporated herein by reference.

[0002] The present invention relates to a heat absorption pack for a secondary battery module that can adjust the internal temperature change to be small by uniformly absorbing thermal energy when the temperature inside the secondary battery module rises, and a secondary battery module including the same and having improved stability against temperature changes inside the module. [Background technology]

[0003] 2. Description of the Related 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-sized devices such as battery packs for hybrid and electric vehicles and 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 multi-layered exterior material that protects the electrode assembly and the electrolyte. The secondary battery may be used in the form of a battery module having a plurality of cells.

[0005] However, such secondary batteries are sensitive to changes in the surrounding temperature, and the electrical performance and safety of such batteries can be significantly affected by such changes.

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

[0007] In order to suppress the heat conduction to adjacent cells in the thermal runaway state of the secondary battery, a technology for preventing thermal runaway has been developed. For example, a technology for improving the heat transfer efficiency by providing a cartridge containing a thermally conductive additive in a battery module has been developed. However, such a conventional technology is intended to cool the heat generated during battery operation, and has a problem that it does not function in the thermal runaway state such as cell explosion. In addition, a technology including a cooling member that absorbs the heat generated inside the secondary battery module and lowers the surrounding temperature has been developed. However, actual thermal runaway often occurs due to the heat generated by a specific cell mounted in the module. In this case, the cooling member has difficulty in uniformly absorbing the heat generated in the cell, and thus the cooling member is damaged during the heat absorption process, which causes a limitation in that the cooling member cannot sufficiently absorb the 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 surrounding temperature and prevent the temperature inside the module from rising rapidly. [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] SUMMARY OF THE PRESENT DISCLOSURE An object of the present invention is to provide a technique capable of suppressing abrupt temperature changes within a secondary battery module by uniformly absorbing heat generated within the module when the module is heated. [Means for solving the problem]

[0011] To solve the above problems, In one embodiment, the present invention comprises: A highly absorbent matrix; A heat dispersing substrate disposed on at least one surface of the highly absorbent matrix; a pouch into which the highly absorbent matrix having the heat dispersing substrate disposed thereon is inserted; The highly absorbent matrix is ​​in a state of being immersed in water, The heat dissipating substrate provides a heat absorbing pack for a secondary battery module, which includes a metal sheet satisfying 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 dispersing substrate can cover 70% or more of the surface of the highly absorbent matrix.

[0016] In addition, the above-mentioned highly absorbent matrix may have a heat dispersion substrate disposed on its surface, and the area in direct contact with the pouch may be 30% or less of the total area of ​​the highly absorbent 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 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.

[0019] Additionally, the highly absorbent matrix may optionally further contain a thermally conductive filler therein together with the resin.

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

[0021] Further, 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 for absorbing heat generated in the plurality of battery cells.

[0022] Here, the plurality of battery cells may be aligned in n rows (where n is greater than or equal to 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. Effect of the Invention

[0023] The heat absorption pack for a secondary battery module according to the present invention includes a highly absorbent matrix impregnated with water inside a pouch, and has a structure in which a heat dispersion substrate is inserted between the highly absorbent matrix and the pouch, so that when heat is generated inside the module, a large amount of heat in the surroundings can be absorbed. Therefore, when the heat absorption pack for a secondary battery module is provided with the highly absorbent matrix, 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, so that 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. [Brief description of the drawings]

[0024] [Figure 1] 1 is a perspective view showing a structure of a secondary battery module according to the present invention; [Diagram 2] 1 is a photographed image of a heat absorbing pack of an embodiment disassembled after internal heating of a secondary battery module. [Diagram 3] 1 is a photographed image of a heat absorbing pack of a comparative example that was disassembled after the internal heating of a secondary battery module. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] Because the present invention is susceptible to various modifications and can 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 it should be understood to include 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 additional possibility of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0028] In addition, 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 in between. 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 in between. In addition, in the present application, being "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 dispersing 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] At this time, the highly absorbent matrix is ​​impregnated with water, and thus can absorb a large amount of thermal energy according to the temperature conditions around the heat absorption pack, i.e., the internal temperature conditions of the secondary battery module to which the heat absorption pack is attached. Specifically, the water is impregnated inside the highly absorbent matrix, and when the external temperature of the pouch rises, it vaporizes and is separated from the highly absorbent matrix. At this time, the water requires a large amount of heat to vaporize, and in order to meet this requirement, the water absorbs the heat around the pouch, thereby preventing 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 uniformly transfer heat from the outside of the pouch to the highly absorbent matrix, thereby preventing the heat from being concentrated in one part of the endothermic pack and damaging the endothermic pack.

[0035] For this purpose, the heat dissipating substrate may include a metal sheet having a 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, etc., either alone or in combination.

[0037] In addition, the heat dissipating substrate includes a metal sheet having high thermal conductivity, but the heat transferred to the highly absorbent matrix through the actual metal sheet must be distributed over the entire surface of the highly absorbent matrix, and therefore may be highly dependent on the thickness of the metal sheet. Therefore, the heat dissipating substrate may have a predetermined thickness in order to transfer the heat around the pouch (i.e., outside the pouch) to the highly absorbent matrix with high efficiency and in a more uniformly distributed manner. In addition, a certain thickness condition may be satisfied for the heat absorption pack, taking into consideration the reduction in the energy density of the secondary battery module due to the heat absorption 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 absorbing 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 means the ratio between the average thickness of the heat absorption pack and the average thickness of the heat dispersion substrate. In the present invention, by making the above ratio satisfy a predetermined range, the energy density of the secondary battery module is prevented from being reduced, and the heat energy can be efficiently dispersed and absorbed by the heat absorption pack without damaging the heat absorption pack when high temperature is generated inside. For this purpose, the heat dispersion substrate can satisfy the above formula 1 at 10 to 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 making the heat dispersion substrate satisfy the formula 1 at 10 or more, the content of the high absorbent matrix is ​​reduced, and the heat absorption efficiency is prevented from being reduced, while by making the formula 1 at 500 or less, the heat around the pouch is not uniformly dispersed in the high absorbent matrix due to the thin thickness of the heat dispersion substrate, and the heat absorption pack is prevented from being damaged.

[0042] The heat dispersion substrate may have an average thickness of 5 μm to 100 μm, and more specifically, may have an average thickness of 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 dispersion substrate to the above range, the present invention can prevent the heat absorption pack from being damaged during heat absorption due to a thin thickness of less than 5 μm that makes it impossible to uniformly transfer heat around the pouch to the highly water-absorbent matrix, while preventing a reduction in the thermal conductivity of the heat dispersion substrate 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 is in direct contact with the pouch so as to satisfy a predetermined area ratio.

[0045] Specifically, the heat dispersing substrate may be arranged to cover 70% or more of the entire surface of the superabsorbent matrix, and more specifically, may be arranged 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 arranged over the entire surface of the superabsorbent matrix, and the area of ​​the superabsorbent matrix directly contacting the pouch may be 0%. The present invention allows the heat around the pouch to be more uniformly dispersed in the superabsorbent matrix by adjusting the area ratio of the heat dispersing substrate covering the surface of the superabsorbent matrix to the above range.

[0046] Meanwhile, as described above, when the heat-absorbing pack is exposed to high temperature conditions, the highly absorbent matrix may have a form in which the water impregnated therein is evaporated and separated, and thus the pouch into which the highly absorbent matrix is ​​inserted may have an expanded form.

[0047] In this case, the superabsorbent matrix may contain a superabsorbent polymer (SAP) or a superabsorbent fiber (SAF) to absorb water efficiently. Here, the superabsorbent polymer (SAP) and the superabsorbent fiber (SAF) may be classified according to their shapes. For example, the superabsorbent polymer (SAP) may have a powder shape, and the superabsorbent fiber (SAF) may have a linear shape.

[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 polyacrylic acid, polyacrylate, polyacrylate graft polymer, starch, crosslinked carboxymethyl cellulose, acrylic acid copolymer, hydrolyzed starch-acrylonitrile graft copolymer, starch-acrylic acid graft copolymer, saponified vinyl acetate-acrylic acid ester copolymer, hydrolyzed acrylonitrile copolymer, hydrolyzed acrylamide copolymer, ethylene-maleic anhydride copolymer, isobutylene-maleic anhydride copolymer, polyvinyl sulfonic acid, polyvinyl phosphonic acid, polyvinyl phosphoric acid, polyvinyl sulfuric acid, 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 highly absorbent 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 highly absorbent 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 components are materials having a network structure with hydrophilic functional groups and can absorb water with high efficiency, so that the heat absorbing pack can uniformly absorb or generate heat.

[0052] In addition, the high-absorbency matrix may have a certain range of water absorption. Specifically, the high-absorbency matrix may have a water absorption of 10 g / g to 500 g / g, 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 of water, preferably 50 g to 200 g of water per 1 g of the high-absorbency matrix. The higher the water absorption of the high-absorbency matrix, the longer the cooling effect can be maintained. However, if the water absorption exceeds 500 g / g, the fluidity of the high-absorbency matrix increases, making it difficult to maintain its shape and unable to provide effective cooling. In addition, if the water absorption of the high-absorbency matrix is ​​less than 10 g / g, the amount of heat absorbed according to the temperature outside the pouch is significantly reduced, and the effect of suppressing a sudden change in the temperature inside the module may be low and inefficient.

[0053] Additionally, 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 may be used without limitation as long as it has excellent heat transfer properties. Specifically, one or more types selected from inorganic oxide fillers, metal hydroxide fillers, inorganic carbide fillers, nitride fillers, metal fillers, and carbon fillers may 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] In addition, 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 so as 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 inside. For example, the pouch may be made of a metal layer, and the inner surface of the metal layer may include an inner layer containing a crosslinked 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] In addition, the inner layer is located on the inner surface of the metal layer and can function to prevent the water impregnated in the highly absorbent matrix from reacting with the metal layer of the pouch. For this purpose, the inner layer can include a crosslinked polyolefin resin. The crosslinked polyolefin resin has low hygroscopicity and can suppress the intrusion of the water impregnated in the highly absorbent matrix, so that the swelling and erosion of the inner layer due to this can be prevented. Here, the polyolefin resin can have a crosslinking degree of 10 to 70%, specifically, a crosslinking degree of 30 to 50%. In addition, the polyolefin resin can be any one or more selected from polypropylene (PP) and polyethylene (PE), and the crosslinked polyolefin resin can specifically include crosslinked polyethylene, crosslinked polypropylene, or a mixture thereof, more specifically, crosslinked polypropylene.

[0060] Furthermore, the endothermic pack may meet a certain thickness requirement to effectively control the temperature change inside 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 results in insufficient flow of thermal energy around the endothermic pack, resulting in a rapid change in the temperature inside the module; if the thickness exceeds 50 mm, the thickness of the battery module increases, which can significantly reduce the energy density.

[0062] The heat absorption pack according to the present invention, having the above-mentioned configuration, is not only capable of absorbing a large amount of heat from the surroundings when heat is generated inside the module, but also capable of uniformly supplying 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 provided in a secondary battery module, it is possible to prevent the temperature around the secondary battery from changing suddenly, thereby improving the performance and stability of the secondary battery according to the surrounding temperature.

[0063] <Secondary battery module> Further, in one embodiment, the present invention provides There is provided a secondary battery module including 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 a sudden rise in temperature inside the module, and thus has the advantage of excellent stability of the battery cells 20 against temperature.

[0067] Here, the housing member 10 serves as a body of a battery module in which the plurality of battery cells 20 are housed. In addition, the housing member 10 is a member in which the plurality of battery cells 20 are housed, and protects the battery cells 20 while transmitting electrical energy generated by the battery cells 20 to the outside.

[0068] For this, the housing member 10 may be composed of a bottom member 11, a side wall member 12, etc. 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 an upper end of the side wall member 12 to protect an upper end of the battery cell 20. In addition, a gas venting member 17 may be included 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 be configured in such a way that it 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 applicable to a lithium secondary battery, and specifically, the battery cell 20 may have a shape such as a square type, a pouch type, a cylindrical type, etc. As one example, the battery cell 20 may be a square or pouch type lithium secondary battery.

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

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

[0076] As another example, a heat absorption pack 30b may be inserted between the battery cells 20. Specifically, the heat absorption pack 30b may be disposed between the individual battery cells 20 that constitute a row, and in some cases, may be disposed between the first row 21a and the second row 21b that are made up of batteries aligned 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 now be described in more detail 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> The highly absorbent fiber (component: acrylic acid copolymer) was impregnated with 10 g of water per 1 g of water. 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, the inside was made into a vacuum state, and the pouch's insertion port 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., the area ratio) are shown in Table 1 below.

[0083] [Table 1]

[0084] <Experimental example.> In order to evaluate the effect of regulating the temperature inside the secondary battery module by the heat absorbing 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 formed by inserting 10 secondary battery cells in two rows into a housing member, 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 in which secondary battery cells were inserted, and temperature sensors were attached to one of the sides and the top of the module.

[0087] In addition, 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: about 20μm) wider than the positive and negative electrodes were prepared as separators. 40 stack unit cells of separator-negative electrode-separator-positive electrode-separator were then 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 in which LiPF6 was added as a lithium salt at a concentration of 1M to an organic solvent in which ethylene carbonate (EC) and ethyl methyl carbonate (EMC) were mixed in a volume ratio of 3:7, and each battery cell was inserted into the housing member in a fully charged state.

[0088] B) Safety evaluation under high temperature conditions To evaluate safety under high temperature conditions, the internal temperature was increased for 30 minutes at a rate of 5°C / min using a heating pad attached to the secondary battery module. (a) After heating the inside of the module for 30 minutes, the internal temperature was measured using two temperature sensors attached to the inside of the module, and the average temperature was calculated as the internal temperature of the module. In addition, (b) after the temperature measurement was completed, the operation of the heating pad was stopped, the inside of the module was cooled to room temperature, and the heat absorption pack attached to the module was disassembled and the presence or absence of damage to the superabsorbent fiber inserted in the pouch was evaluated with the naked eye. The results are shown in Table 2 and Figures 2 and 3 below, and the presence or absence of damage to the superabsorbent fiber was indicated by ◯ if there was damage and × if there was no damage.

[0089] [Table 2]

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

[0091] Specifically, it was confirmed that, as internal heating by the heating pad installed inside the module progresses, the endothermic pack of the embodiment absorbs the heat and maintains the temperature inside the module at less than about 130° C. Also, as shown in FIG. 2, it was confirmed that the endothermic pack of the embodiment has the superabsorbent fiber inserted inside the pouch uniformly absorbing the heat around the pouch, and no internal damage occurs 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 highly absorbent 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 fully absorbed, but as shown in Figure 3, internal damage occurred to both the highly absorbent fiber and the pouch when absorbing heat, 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 making it possible to more stably control the temperature inside the module.

[0094] Although the present invention has been described above with reference to preferred embodiments, a person skilled in the art or having ordinary knowledge in the art will understand that the present invention can be modified and changed in various ways 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 contents 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 component 15: Rear member 16: Partition wall material 17: Gas venting parts 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 disposed on the outer surface of the battery cell 30b: A heat absorbing pack disposed between a plurality of rows of aligned battery cells. 40: Heat sink

Claims

1. A highly absorbent matrix; a heat dispersing substrate disposed on at least one surface of the highly absorbent matrix; a pouch into which the highly absorbent matrix having the heat dispersing substrate disposed thereon is inserted; The highly absorbent matrix is ​​in a state of being immersed in water; The heat dissipating substrate comprises a metal sheet satisfying the following formula 1 by 10 to 500: [Formula 1] T ｐａｃｋ / T ｓｈｅｅｔ 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).

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

5. 2. The heat absorption 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 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 sulfuric acid, 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 absorption pack for a secondary battery module according to claim 1, wherein the highly absorbent matrix further comprises 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 (n≧2), and the heat absorption packs are arranged between the rows of the arranged battery cells.

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

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