KR20230159054A - Secondary battery module improved with satability of temperature in battery module - Google Patents

Abstract

The present invention relates to a temperature control pack for a secondary battery module and a secondary battery module including the same. The temperature control pack has a structure in which a highly absorbent mat which is inserted into a pouch, and in which an aqueous solution containing a temperature control agent having a negative enthalpy of solution is impregnated inside. According to the present invention, in high temperature conditions of around 100℃ or higher, a large amount of heat from the surroundings is absorbed, and even in low temperature conditions of below -10℃, a large amount of heat energy can be released to the surroundings. Therefore, when a secondary battery is equipped with the temperature control pack, rapid change in surrounding temperature of the secondary battery can be prevented, and the performance and stability corresponding to the surrounding temperature of the secondary battery can be improved.

Description

Secondary battery module with improved temperature stability inside the module {SECONDARY BATTERY MODULE IMPROVED WITH SATABILITY OF TEMPERATURE IN BATTERY MODULE}

The present invention relates to a temperature control pack for a secondary battery module that can control the temperature change inside the secondary battery module so that the temperature change is not large, and a secondary battery module including the same with improved stability against temperature change inside the module.

Recently, secondary batteries have been widely applied not only to small devices such as portable electronic devices, but also to medium-to-large devices such as battery packs of hybrid vehicles or electric vehicles or power storage devices.

A secondary battery includes an electrode assembly including an anode, a cathode, and a separator, an electrolyte, and a multilayer exterior material that protects them as a body. This secondary battery can be used in the form of a battery module equipped with a plurality of cells.

However, these secondary batteries are sensitive to changes in surrounding temperature, so their electrical performance and safety may be greatly affected.

As an example, the electrode assembly provided in a secondary battery generates heat while going through the process of charging and discharging. The temperature rise due to this heat generation not only reduces the performance of the secondary battery cell, but also reduces the temperature of the secondary battery cell. A problem may occur in which one of the secondary battery cells explodes due to internal factors of the battery module, such as an increase in temperature, or one secondary battery cell explodes due to an external shock. Moreover, the explosion of one secondary battery cell may cause a problem in which high temperature and high pressure are applied to other secondary battery cells around it, leading to a series of explosions of secondary battery cells.

In order to suppress heat conduction to adjacent cells in the above-described thermal runaway situation of secondary batteries, technology for thermal runaway prevention sheets has been developed. Some prior technologies include a cooling member for cooling the battery module when heat is generated, or provide a cartridge containing a heat conductive additive within the battery module, thereby improving heat transfer efficiency. However, this prior art is intended to cool the heat generated during battery operation, and has limitations in that it cannot function in thermal runaway situations such as cell explosion.

As another example, in the case of a secondary battery containing a liquid electrolyte, if the surrounding temperature drops to -20°C to -10°C, freezing of the liquid electrolyte may occur, which has the limit of rapidly deteriorating the characteristics of the battery. there is. To solve this problem, a technology using anti-freezing additives in the liquid electrolyte has been developed. However, when additional additives are used in the liquid electrolyte, the low-temperature characteristics are improved, but the wettability of the electrode assembly is low, and the wettability at room temperature and/or There is a limitation in battery performance at high temperatures.

Therefore, in a secondary battery module containing a secondary battery, when the temperature inside the module, that is, the surrounding temperature of the secondary battery, is a high temperature/heat generation condition that induces thermal runaway of the battery, a rapid increase in the surrounding temperature is suppressed, and -10 There is a need for technology that can prevent freezing of the liquid electrolyte included in the battery under low temperature conditions such as ℃ or lower.

Japanese Registered Patent Publication No. 2018-6594435 Republic of Korea Patent Publication No. 10-2019-0009161

Accordingly, the purpose of the present invention is to suppress rapid temperature changes inside the secondary battery module, thereby suppressing or delaying ignition or explosion of the secondary battery under heat generation or high temperature conditions such as thermal runaway of the battery, and preventing or delaying ignition or explosion of the secondary battery at low temperatures below -10°C. The goal is to provide technology to prevent performance degradation due to freezing of secondary batteries when exposed to the environment.

In order to solve the above-mentioned problems,

In one embodiment, the present invention

pouch; And a highly absorbent matrix inserted into the pouch,

The highly absorbent matrix is impregnated with an aqueous solution in which a temperature regulator having a negative melting enthalpy is dissolved,

The aqueous solution provides a temperature control pack for a secondary battery module that induces an endothermic reaction as the water in the aqueous solution evaporates when the external temperature of the pouch increases.

Here, the temperature regulator may have a dissolution enthalpy of -150 kJ/mol to -10 kJ/mol, and these temperature regulators include calcium chloride (CaCl ₂ ), calcium oxide (CaO), potassium chloride (KCl), and potassium hydroxide ( It may contain one or more of KOH) and magnesium chloride (MgCl ₂ ).

Additionally, the superabsorbent matrix may be in the form of superabsorbent polymer (SAP) or superabsorbent fiber (SAF).

In addition, the highly absorbent matrix includes polyacrylic acid, polyacrylate, polyacrylate graft polymer, starch, cross-linked carboxymethylated cellulose, acrylic acid copolymer, hydrolyzed starch-acrylnitrile 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, polyvinylsulfonic acid, polyvinyl Phosphonic acid, polyvinyl phosphoric acid, polyvinyl sulfate, sulfonated polystyrene, polyvinylamine, polydialkylaminoalkyl (meth)acrylamide, polyethyleneimine, polyallylamine, polyallylguanidine, polydimethyldiallylammonium hydroxide, It may contain one or more resins selected from the group consisting of quaternized polystyrene derivatives, guanidine-modified polystyrene, quaternized poly(meth)acrylamide, polyvinylguanidine, and mixtures thereof, and in some cases, the resin may be added to the interior together with the resin. It may further include a thermally conductive filler.

This highly absorbent matrix may contain 10 g/g to 500 g/g of an aqueous solution.

Meanwhile, the temperature control pack may have a thickness of 0.1 mm to 50 mm.

Furthermore, in one embodiment of the present invention,

no housing;

a plurality of battery cells inserted into the housing member; and

A secondary battery module including a temperature control pack according to the present invention that absorbs heat generated from the plurality of battery cells is provided.

Here, the plurality of battery cells may be arranged in n rows (where n ≥ 2), and in this case, the temperature control pack may be placed between the rows formed by the arranged battery cells, and/or the arranged It may be placed in the space between the outer surface of the row of battery cells and the housing member.

The temperature control pack for secondary battery modules according to the present invention has a structure in which a high-absorbency mat impregnated with an aqueous solution containing a temperature control agent having a negative melting enthalpy is inserted into the pouch, thereby maintaining high temperatures around 100°C or higher. Under certain conditions, it can absorb a large amount of heat from the surroundings and emit a large amount of heat energy to the surroundings even under low temperature conditions below -10℃, so when equipped with a secondary battery module, it prevents the surrounding temperature of the secondary battery from rapidly changing. This can improve the performance and stability of the secondary battery depending on the surrounding temperature.

Figure 1 is a perspective view showing the structure of a secondary battery module according to the present invention.

Since the present invention can be subject to various changes and can have various embodiments, specific embodiments will be described in detail in the detailed description.

However, this is not intended to limit the present invention to specific embodiments, and should be understood to include all changes, equivalents, and substitutes included in the spirit and technical scope of the present invention.

In the present invention, terms such as "comprise" or "have" are intended to designate the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, but are not intended to indicate the presence of one or more other features. It should be understood that this does not exclude in advance the possibility of the existence or addition of elements, numbers, steps, operations, components, parts, or combinations thereof.

Additionally, in the present invention, when a part of a layer, membrane, region, plate, etc. is described as being "on" another part, this includes not only being "directly on" the other part, but also cases where there is another part in between. . Conversely, when a part of a layer, membrane, region, plate, etc. is described as being “under” another part, this includes not only being “immediately below” the other part, but also cases where there is another part in between. Additionally, in this application, being placed “on” may include being placed not only at the top but also at the bottom.

Hereinafter, the present invention will be described in more detail.

Temperature control pack for secondary batteries

In one embodiment, the present invention

pouch; And a highly absorbent matrix inserted into the pouch,

The highly absorbent matrix is impregnated with an aqueous solution in which a temperature regulator having a negative melting enthalpy is dissolved,

The aqueous solution provides a temperature control pack for a secondary battery module that induces an endothermic reaction as the water in the aqueous solution evaporates when the external temperature of the pouch increases.

The temperature control pack according to the present invention is a component inserted into the inside of a secondary battery module and has a structure in which a high-absorbency matrix impregnated with an aqueous solution is inserted inside a pouch, where the aqueous solution is a temperature control having a negative enthalpy of dissolution. It is characterized in that it is a dissolved aqueous solution.

'Enthalpy of dissolution' refers to the amount of heat released or absorbed when 1 mole of solute is dissolved in water, a solvent. A negative value of enthalpy of dissolution means that an exothermic reaction occurs that releases heat when the solute is dissolved in water, a solvent. means that

That is, the present invention has a structure in which an aqueous solution containing a temperature regulator that causes an exothermic reaction when dissolved in water is impregnated into a highly absorbent matrix, and the phase change temperature and/or amount of heat of the water contained in the aqueous solution are adjusted accordingly to control the temperature control pack. Depending on the surrounding temperature conditions, a large amount of heat energy can be absorbed and/or released.

More specifically, the temperature control pack primarily absorbs surrounding heat energy to vaporize the water contained in the aqueous solution when the external temperature of the pouch increases, and at the same time, secondarily absorbs heat energy to separate the temperature control agent and water. can do. This means that the heat energy (or heat of vaporization) required for the phase change of water and separation from the temperature regulator in the water of the aqueous solution in which the temperature regulator is dissolved may have more heat than the heat energy required to vaporize pure water. Therefore, the temperature control pack according to the present invention contains an aqueous solution in which the temperature control agent is dissolved, so that it can absorb more heat energy compared to the case of using pure water, thereby preventing the temperature around the pouch from rising rapidly. Therefore, a longer time may be required for the internal temperature of the module to reach or exceed 100°C.

In addition, the temperature control pack emits heat energy to the surroundings to freeze the water contained in the aqueous solution when the external temperature of the pouch decreases, thereby suppressing a rapid decrease in the surrounding temperature. Here, the heat energy (or heat of solidification) required to freeze the water contained in the aqueous solution may have more heat than the heat energy required to freeze pure water, and accordingly, the temperature at which the temperature control pack emits heat energy is that of pure water. Freezing can be lower than 0℃. In other words, since the temperature control pack according to the present invention contains an aqueous solution in which the temperature control agent is dissolved, it can emit more heat energy compared to the case of using pure water, thereby preventing the temperature around the pouch from falling rapidly. Therefore, it is possible to prevent the liquid electrolyte solutions of the secondary batteries provided inside the module from freezing under low temperature conditions of less than -10°C, specifically -30 to -15°C.

To this end, the temperature regulator may satisfy a certain range of enthalpy of dissolution. Specifically, the temperature regulator may have a melting enthalpy having a negative value in a certain range, more specifically -150 kJ/mol to -10 kJ/mol; -120 kJ/mol to -10 kJ/mol; -100 kJ/mol to -10 kJ/mol; -120 kJ/mol to -20 kJ/mol; -100 kJ/mol to -30 kJ/mol; -50 kJ/mol to -10 kJ/mol; -90 kJ/mol to -60 kJ/mol; Alternatively, it may include a substance having a dissolution enthalpy of -85 kJ/mol to -30 kJ/mol.

Temperature regulators with such melting enthalpy include calcium chloride (CaCl ₂ , melting enthalpy: -81±0.5 kJ/mol), calcium oxide (CaO, melting enthalpy: -82.5±0.5 kJ/mol), and potassium chloride (KCl, melting enthalpy: -82.5±0.5 kJ/mol). -74±0.5 kJ/mol), magnesium chloride (MgCl ₂ ), magnesium sulfate (MgSO ₄ , enthalpy of dissolution: -91±0.5 kJ/mol), potassium hydroxide (KOH, enthalpy of dissolution: -46±0.5 kJ/mol) , sodium hydroxide (NaOH, enthalpy of dissolution: -42±0.5 kJ/mol), etc. can be used alone or in combination.

As an example, the temperature regulator may include one or more of calcium chloride (CaCl ₂ ), calcium oxide (CaO), potassium chloride (KCl), potassium hydroxide (KOH), and magnesium chloride (MgCl ₂ ).

On the other hand, the highly absorbent matrix impregnated with the aqueous solution may have a form in which water from the impregnated aqueous solution is released and the temperature regulator remains inside when the temperature control pack is exposed to high temperature conditions, and the temperature control pack is exposed to low temperature conditions. When exposed, it may take a frozen form impregnated with an aqueous solution.

Additionally, the super absorbent matrix may include a super absorbent polymer (SAP) or super absorbent fiber (SAF) to absorb the aqueous solution in which the temperature regulator is dissolved with high efficiency. Here, the super absorbent polymer (SAP) and super absorbent fiber (SAF) can be distinguished by their shape. For example, superabsorbent polymer (SAP) may have a powder shape, and the superabsorbent fiber (SAF) may have a linear shape.

In addition, the components constituting the superabsorbent polymer (SAP) and superabsorbent fiber (SAF) may be the same or different. Specifically, the highly absorbent matrix is polyacrylic acid, polyacrylate, polyacrylate graft polymer, starch, cross-linked carboxymethylated cellulose, acrylic acid copolymer, hydrolyzed starch-acrylnitrile 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, polyvinylsulfonic acid, poly Vinylphosphonic 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, polyvinylguanidine, and mixtures thereof.

As an example, the superabsorbent matrix may include, but is not limited to, one or more selected from the group consisting of crosslinked polyacrylic acid salts, crosslinked polyacrylic acid, and crosslinked acrylic acid copolymers.

The type of acrylic acid copolymer used as the superabsorbent matrix in the present invention is not particularly limited, but is preferably acrylic acid monomer and maleic acid, itaconic acid, acrylamide, 2-acrylamide-2-methylpropanesulfonic acid, 2-( It may be a copolymer containing one or more comonomers selected from the group consisting of meta)acryloylethanesulfonic acid, 2-hydroxyethyl (meth)acrylate, and styrenesulfonic acid.

The above ingredients are substances that have a network structure with a hydrophilic functional group, and can not only absorb aqueous solutions with high efficiency, but also uniformly disperse the temperature control agents dissociated in the aqueous solution within the structure, so the temperature control pack has an endothermic or exothermic effect. can be implemented uniformly.

In addition, the highly absorbent matrix can satisfy a certain range of absorption capacity for an aqueous solution in which a temperature regulator is dissolved. Specifically, the highly absorbent matrix may have an absorption amount in an aqueous solution of 10 g/g to 500 g/g, specifically 50 g/g to 200 g/g, but is not limited thereto. This means that 10 g to 500 g of aqueous solution, preferably 50 g to 200 g, can be absorbed per 1 g of the superabsorbent matrix. The more the superabsorbent matrix absorbs the aqueous solution in which the temperature regulator is dissolved, the more it absorbs. The duration of the cooling effect can be improved, but if it exceeds 500 g/g, the fluidity of the superabsorbent matrix increases and it is difficult to maintain its shape, making effective cooling impossible. In addition, if the absorption amount of the highly absorbent matrix in an aqueous solution is less than 10 g/g, the amount of heat absorbed or released depending on the external temperature of the pouch is significantly lowered, so the effect of suppressing rapid changes in the internal temperature of the module is low and may be inefficient. .

In addition, the highly absorbent matrix may further include a heat conductive filler therein to better transfer heat to the aqueous solution impregnated within the matrix.

The thermally conductive filler may be used without limitation as long as it has excellent heat transfer properties, but specifically, one or more selected from the group consisting of inorganic oxide filler, metal hydroxide filler, inorganic carbide filler, nitride filler, metal filler, and carbon filler may be used. You can.

Here, examples of the inorganic oxide filler include aluminum oxide, magnesium oxide, zinc oxide, or silicon oxide; Examples of the metal hydroxide filler include aluminum hydroxide or magnesium hydroxide; Examples of the inorganic carbide filler include silicon carbide; Examples of the nitride filler include aluminum nitride, boron nitride, or 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 or graphite.

In addition, the thermally conductive filler is not particularly limited in shape, but has a spherical shape with a high specific surface area to effectively transfer heat inside the highly absorbent matrix, or to form a thermal network with adjacent thermally conductive fillers. It may have a needle-like or fibrous form.

Furthermore, the pouch can be applied without particular restrictions as long as it can well transfer external heat to the highly absorbent matrix inserted inside. For example, the pouch may be composed of a metal layer, and the inner surface of the metal layer may include an inner layer containing a crosslinked polyolefin-based resin.

The metal layer may include an aluminum layer that can effectively transfer heat from the outside of the temperature control pack to the inside and has a strength above a certain level to resist external force.

In addition, the inner layer is located on the inner side of the metal layer and can function to prevent the metal layer from reacting with the aqueous solution impregnated in the highly absorbent matrix. To this end, the inner layer may include a crosslinked polyolefin-based resin. The cross-linked polyolefin resin has low hygroscopicity and can suppress the intrusion of the aqueous solution impregnated into the highly absorbent matrix, thereby preventing expansion or erosion of the inner layer. Here, the polyolefin-based resin may have a crosslinking degree of 10 to 70%, and specifically, may have a crosslinking degree of 30 to 50%. In addition, the polyolefin-based resin may be at least one selected from the group consisting of polypropylene (PP) and polyethylene (PE), and the cross-linked polyolefin-based resin is specifically cross-linked polyethylene, cross-linked polypropylene, Or it may include a mixture thereof, and more specifically, it may be crosslinked polypropylene.

Furthermore, the temperature control pack can satisfy certain thickness conditions in order to effectively control changes in module internal temperature. Specifically, the temperature control 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; Alternatively, it may have a thickness of 1 mm to 5 mm.

The present invention adjusts the thickness of the temperature control pack to the above range, so that if it is less than 0.1 mm, the temperature inside the module may change rapidly due to insufficient heat energy entering and exiting around the temperature control pack due to the excessively thin thickness of the temperature control pack. If it exceeds 50 mm, the thickness of the battery module increases and the energy density may be significantly reduced.

The temperature control pack according to the present invention has the above-described configuration, so that it can absorb a large amount of ambient heat under high temperature conditions around 100℃ or higher, and can emit a large amount of heat energy to the surroundings even under low temperature conditions below -10℃. Therefore, when this is provided in the secondary battery module, the surrounding temperature of the secondary battery can be prevented from rapidly changing, and through this, the performance and stability of the secondary battery according to the surrounding temperature can be improved.

Secondary battery module

Furthermore, in one embodiment of the present invention,

A secondary battery module including a secondary battery and a temperature control pack for secondary batteries according to the present invention described above is provided.

Figure 3 is a perspective view showing the structure of the secondary battery module 1 according to the present invention, which will be described in more detail with reference to Figure 3.

The 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 temperature control pack 30 that absorbs heat generated from the plurality of battery cells.

The secondary battery module 1 according to the present invention includes a plurality of battery cells 20, and is equipped with the temperature control pack 30 of the present invention described above along with these battery cells, so that the temperature inside the module rapidly increases. There is an advantage in that the temperature stability of the battery cell 20 is excellent since it can be prevented from rising or falling.

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

To this end, the housing member 10 may be composed of a bottom member 11 and a side wall member 12. The bottom member 11 supports the plurality of battery cells 20 on which the plurality of battery cells 20 are seated. Additionally, a heat sink 40 may be disposed between the bottom member 11 and the battery cell 20, and the heat sink 40 transfers heat generated from the battery cell 20 to the bottom member 11. In addition, the floor member 11 may be configured to cool the heat received from the heat sink 40 by transferring it to the outside.

In addition, the side wall member 12 forms a side part of the housing member 10 and may discharge heat generated in the battery cell 20 to the outside.

The housing member 10 may further include a cover member 13 provided on the top of the side wall member 12 to protect the upper end of the battery cell 20. In addition, a gas venting member 17 is included between the cover member 13 and the upper end of the battery cell 20, so that gases generated from the battery cell 20 during charging and discharging can be discharged to the outside.

In addition, the housing member 10 may include a front member 14 and a rear member 15 adjacent to the side wall member 12, thereby surrounding the sides of the plurality of battery cells 20. It can be configured in the form

Furthermore, the housing member 10 may be provided with additional components such as a bus bar member (not shown) that electrically connects the battery cell 20 to the outside.

Meanwhile, the type of the battery cell 20 is not particularly limited as long as it can be applied as a lithium secondary battery, but specifically, it may have a shape such as a square shape, a pouch shape, or a cylindrical shape. As an example, the battery cell 20 may be a prismatic or pouch-type lithium secondary battery.

Additionally, the battery cells 20 may be inserted into the housing member 10 and arranged in n rows (where n≥2) to face the side members 12 of the housing member 10. Specifically, the battery cells 20 may be arranged in two or more rows, three or more rows, or two to four rows to face the side members 12.

The battery cells 20 arranged in this way can be arranged with a temperature control pack 30 adjacent to them. As one example, the temperature control pack 30a may be placed on the outer surface of the aligned battery cells 20, that is, in the space between the housing member 10 and the battery cells 20.

As another example, a temperature control pack 30b may be inserted between the battery cells 20. Specifically, the temperature control pack 30b may be disposed between individual battery cells 20 constituting one row, and in some cases, a first row composed of battery cells aligned as shown in FIG. 1 ( It can be placed between 21a) and the second row 21b.

In this way, by placing the temperature control pack 30 adjacent to the battery cell 20, when heat is generated in the battery cell 20, it can immediately absorb the heat, thereby preventing rapid temperature changes inside the module. can do.

Hereinafter, the present invention will be described in more detail through examples and experimental examples.

However, the following examples and experimental examples only illustrate the present invention, and the content of the present invention is not limited to the following examples.

Examples and comparative examples. Manufacturing of temperature control packs

As shown in Table 1, 10 g per 1 g of superabsorbent fiber (ingredient: acrylic acid copolymer) was impregnated with an aqueous solution saturated with a temperature regulator at 24°C. Separately, an aluminum pouch with a width of 10 cm and a length of 35 cm containing an aluminum layer and a polyethylene (PE) layer with a cross-linking degree of 40 ± 2% on the inside was prepared, and a highly absorbent matrix impregnated with an aqueous solution was added to the prepared aluminum pouch. It was inserted, the inside was changed to a vacuum state, and the pouch's inlet was sealed to produce a temperature control pack with an average thickness of about 3 mm.

At this time, in Comparative Example 1, the superabsorbent fiber was impregnated with distilled water in which the temperature regulator was not dissolved, and in Comparative Example 2, ammonium nitrate (NH ₄ NO ₃ , enthalpy of dissolution: 25.5 ± 0.5 kJ/mol) was used as the temperature regulator. .

Highly absorbent matrix types thermostat component Example 1 super absorbent fiber KOH Example 2 super absorbent fiber CaCl Example 3 super absorbent fiber CaO Comparative Example 1 super absorbent fiber - Comparative Example 2 super absorbent fiber NH ₄ NO ₃

Experiment example.

The following experiment was performed to evaluate the temperature control effect inside the secondary battery module according to the temperature control pack according to the present invention.

A) Production of secondary battery module

At this time, the secondary battery module is inserted into the housing member in two rows, 10 secondary battery cells per row, as shown in FIG. 1, and the temperature is adjusted between the outer surface of the battery cell and each row, respectively, manufactured in Examples and Comparative Examples. The pack was placed.

Additionally, in order to control the temperature inside the module, instead of a heat sink, ① a heating pad as a heating means or ② a cooler using a cryogenic refrigerant as a cooling means was introduced at the bottom of the battery cell.

In addition, for the battery cells inserted into the module, 40 anodes and 40 cathodes were prepared, and 120 porous polyethylene separators (width 9.5 cm Х length 34.5 cm, average thickness: about 20 ㎛) wider than the anode and cathode were prepared as separators. Next, 40 unit cells for the separator-cathode-separator-anode-separator stack were stacked and manufactured into a square shape with a width of 10 cm, a length of 35 cm, and a thickness of 1.6 cm. At this time, the electrolyte injected into each battery cell is an organic solvent in which ethylene carbonate (EC) and ethyl methyl carbonate (EMC) are mixed in a volume ratio of 3:7, and LiPF6 as a lithium salt is added at a concentration of 1M. A liquid electrolyte was used, and each manufactured battery cell was inserted into the housing member in a fully charged state.

B) Safety evaluation in high temperature conditions

To evaluate safety in high temperature conditions, the internal temperature was raised to 150°C at a rate of 5°C/min for 30 minutes using a heating pad mounted on the secondary battery module and maintained for 30 minutes while the battery inserted into the module was heated. The initial time taken for the battery cell to ignite was measured. The results are shown in Table 2 below.

B) Evaluation under low temperature conditions

In order to evaluate whether the electrolyte was frozen under low temperature conditions, the resistance of the secondary battery module according to temperature changes was measured. Specifically, the resistance during charging and discharging of the secondary battery module was measured while lowering the temperature by 5°C from room temperature (25°C) to low temperature (-20°C) using a cooler mounted on the secondary battery module. At this time, the charging and discharging was performed at CC-CV (Constant current-Constant voltage) with a charging voltage of 2.6V and a current density of 400 mAh, and then discharged to 1.8V with a discharge capacity of 1000 mAh with a rest period of 10 minutes.

From the measured results, the resistance change rate of the module when charged and discharged at low temperature (-20°C) was calculated based on the resistance value of the module when charged and discharged at room temperature (25°C), and the results are shown in Table 2 below.

Time required for initial ignition of a battery cell Resistance increase rate at low temperature Example 1 37 minutes 480% Example 2 44 minutes 425% Example 3 45 minutes 380% Comparative Example 1 23 minutes 1180% Comparative Example 2 18 minutes 1090%

As shown in Table 2, the temperature control pack according to the present invention suppresses the temperature inside the module from rapidly rising under high temperature conditions, while the temperature inside the module falls below -10°C under low temperature conditions, preventing the battery cells from freezing. It can be seen that this is suppressed.

Specifically, in the secondary battery modules of the embodiment according to the present invention, a rapid rise in internal temperature is suppressed under high temperature conditions, so it takes more than 35 minutes for the battery cell inserted into the module to ignite, and freezing of the cell is suppressed at low temperature, reducing resistance. This increasing rate was confirmed to be low, below 500%.

From these results, the temperature control pack according to the present invention has a structure in which a highly absorbent mat impregnated with an aqueous solution containing a temperature control agent having a negative melting enthalpy is inserted into the pouch, thereby maintaining high temperatures around 100°C or higher. Under certain conditions, it can absorb a large amount of heat from the surroundings and emit a large amount of heat energy to the surroundings even under low temperature conditions below -10℃, so when equipped with a secondary battery module, it prevents the surrounding temperature of the secondary battery from rapidly changing. It can be seen that through this, the performance and stability of the secondary battery can be improved according to the surrounding temperature.

Although the present invention has been described above with reference to preferred embodiments, those skilled in the art or have ordinary knowledge in the relevant technical field will understand that it does not deviate from the spirit and technical scope of the present invention as set forth in the claims to be described later. It will be understood that various modifications and changes can be made to the present invention within the scope.

Therefore, the technical scope of the present invention should not be limited to what is described in the detailed description of the specification, but should be determined by the scope of the patent claims.

1: Secondary battery module
10: Housing member 11: Floor member
12: side wall member 13: cover member
14: front member 15: rear member
16: partition member 17: gas venting member
20: Battery cell 21: Column with battery cells sorted
21a: First row in which battery cells are aligned
21b: Second row in which battery cells are aligned
30: Temperature control pack
30a: Temperature control pack disposed on the outer side of the battery cell
30b: Temperature control pack disposed between a plurality of rows in which battery cells are aligned
40: heat sink

Claims (11)

pouch; And a highly absorbent matrix inserted into the pouch,
The highly absorbent matrix is impregnated with an aqueous solution in which a temperature regulator having a negative melting enthalpy is dissolved,
The aqueous solution is a temperature control pack for a secondary battery module that induces an endothermic reaction as the water in the aqueous solution evaporates when the external temperature of the pouch increases.
According to paragraph 1,
The temperature control agent is a temperature control pack for a secondary battery module having a dissolution enthalpy of -150 kJ/mol to -10 kJ/mol.
According to paragraph 1,
The temperature control agent is a temperature control pack for a secondary battery module containing one or more of calcium chloride (CaCl ₂ ), calcium oxide (CaO), potassium chloride (KCl), potassium hydroxide (KOH), and magnesium chloride (MgCl ₂ ).
According to paragraph 1,
The highly absorbent matrix is a temperature control pack for secondary battery modules made of superabsorbent polymer (SAP) or superabsorbent fiber (SAF).
According to paragraph 1,
The highly absorbent matrix is polyacrylic acid, polyacrylate, polyacrylate graft polymer, starch, cross-linked carboxymethylated cellulose, acrylic acid copolymer, hydrolyzed starch-acrylnitrile 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, polyvinylsulfonic acid, polyvinylphosphonic acid, Polyvinyl phosphoric acid, polyvinyl sulfate, sulfonated polystyrene, polyvinylamine, polydialkylaminoalkyl (meth)acrylamide, polyethyleneimine, polyallylamine, polyallylguanidine, polydimethyldiallylammonium hydroxide, quaternized polystyrene. A temperature control pack for a secondary battery module comprising at least one resin selected from the group consisting of derivatives, guanidine-modified polystyrene, quaternized poly(meth)acrylamide, polyvinylguanidine, and mixtures thereof.
According to paragraph 1,
The highly absorbent matrix is a temperature control pack for secondary battery modules that further contains thermally conductive filler inside.
According to paragraph 1,
The highly absorbent matrix is a temperature control pack for secondary battery modules containing an aqueous solution of 10 g/g to 500 g/g.
According to paragraph 1,
The temperature control pack is a temperature control pack for secondary battery modules with a thickness of 0.1 mm to 50 mm.
no housing;
a plurality of battery cells inserted into the housing member; and
A secondary battery module comprising the temperature control pack according to claim 1, which absorbs heat generated from the plurality of battery cells.
According to clause 9,
A secondary battery module in which a plurality of battery cells are arranged in n rows (where n≥2), and a temperature control pack is placed between the rows formed by the arranged battery cells.
According to clause 9,
A secondary battery module in which a plurality of battery cells are arranged in n rows (where n≥2), and a temperature control pack is placed in the space between the outer surface of the row formed by the arranged battery cells and the housing member.

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