KR102183680B1 - Method For Battery Module - Google Patents

Abstract

The present application relates to a method of manufacturing a battery module capable of preventing the resin composition from protruding out of the battery module and curing when the resin composition is cured. The present application also provides a battery module capable of preventing the resin composition from being cured by protruding out of the battery module through an injection hole due to residual pressure in the battery module; A battery pack including the battery module; And a vehicle including the battery module or the battery pack.

Description

Manufacturing method of battery module {Method For Battery Module}

The present application relates to a method of manufacturing a battery module.

The secondary battery includes a nickel cadmium battery, a nickel hydride battery, a nickel zinc battery, or a lithium secondary battery. A typical example is a rechargeable lithium battery, and a rechargeable lithium battery mainly uses lithium oxide and a carbon material as a positive electrode active material and a negative electrode active material, respectively.

A secondary battery includes an electrode assembly in which a positive electrode plate and a negative electrode plate to which a positive electrode active material and a negative electrode active material are applied, respectively, are disposed with a separator therebetween, and a packaging material for sealing and receiving the electrode assembly together with an electrolyte. Secondary batteries can be classified into can-type and pouch-type according to the shape of the exterior material.

In recent years, secondary batteries are widely used not only in small devices such as portable electronic devices, but also in mid- to large-sized devices such as automobiles and power storage devices.

When a secondary battery is used in such a medium or large-sized device, a large number of secondary batteries are electrically connected to increase capacity and output. Pouch-type secondary batteries are widely used in such medium and large-sized devices due to advantages such as low weight, low manufacturing cost, and easy shape transformation.

However, pouch-type secondary batteries generally do not have high mechanical stiffness and are difficult to stack because the battery itself does not include a structure for forming a bond between the batteries. Therefore, when constructing a battery module including a plurality of pouch-type secondary batteries, a coupling member such as a separate cartridge to protect the secondary battery stack from external impacts, prevent its movement, and facilitate stacking Configuration is required.

The conventional method of fixing a plurality of secondary batteries in the internal space of a battery module is a method of applying an overlap design of a secondary battery body, a method of applying surface pressure to a large area of the body, or an electrode terminal of the secondary battery. There was a method of fixing the busbar by laser welding. However, according to this conventional method, when external vibration is applied, not only the body part of the secondary battery shakes, but also the mechanical shock is transmitted to the electrode tab drawn out from the electrode assembly and the electrode lead connected thereto, thereby affecting the electrical connection state. There was a crazy problem.

Korean Patent Publication No. 2016-0105354

In order to solve the above-described problem, a method capable of minimizing the effect of external vibration by injecting and curing a resin composition into a battery module was used. For example, the above method is known in Patent Document 1, and in the method of Patent Document 1, by forming a heat transfer path in the battery module using a resin composition, a method of forming a module that is more compact and has excellent output compared to volume It is disclosed.

However, in the above method, when the resin composition injected into the battery module is cured, the residual pressure in the battery module protrudes to the outside of the battery module and is cured, and the protruding portion makes post-processing difficult, and in other battery module performance or appearance. Since a problem occurs, there is a problem in that the protruding part must be additionally removed.

An object of the present application is to provide a method of manufacturing a battery module capable of preventing the resin composition from being cured by protruding out of the battery module through an injection hole due to residual pressure in the battery module during curing of the resin composition.

Another object of the present application is a battery module capable of preventing curing by protruding to the outside of the battery module through an injection hole due to residual pressure in the battery module; A battery pack including the battery module; And a vehicle including the battery module or the battery pack.

Hereinafter, embodiments of the present application will be described in detail with reference to the accompanying drawings.

Meanwhile, the size and shape of each constituent member configured for convenience of explanation may be exaggerated or reduced.

The method of manufacturing a battery module of the present application includes a resin composition injection step of injecting a resin composition into a battery module case through an injection hole formed in a lower plate or sidewall of a battery module case in which a plurality of battery cells are accommodated; And closing the injection hole by applying a curable material to the injection hole to cure it.

1 is a cross-sectional view showing an exemplary resin composition injection step of the present application. The injector 40 may inject the resin composition 30 into the battery module case through the injection hole 20 formed in the lower plate 10a of the battery module case in which the plurality of battery cells 50 are accommodated.

In the present application, the injector 40 for injecting the resin composition 30 into the battery module case is not particularly limited, and a known injector may be used as long as it is capable of injecting the resin composition 30. For example, the injector 30 may be an injector including a cartridge for accommodating one or more resin compositions, a mixer for mixing the resin composition, a nozzle for discharging the mixture of the resin composition, and a driving unit for controlling the movement of the resin composition. have.

In the present application, the resin composition 30 may be an adhesive material, and may also be a solvent type, an aqueous type, or a non-solvent type. In addition, the resin composition may be an active energy curing type, a moisture curing type, a thermal curing type, or a room temperature curing type.

In one embodiment, the resin composition 30 may be a two-component resin composition including a main material and a curing agent. As the subject matter, a silicone resin, polyol resin, epoxy resin, or acrylic resin may be used. Meanwhile, a known curing agent suitable for the subject may be used as the curing agent. For example, when the main material is a silicone resin, the curing agent may use a siloxane compound. If the main material is a polyol resin, the curing agent may use an isocyanate compound. If the subject is an epoxy resin, the curing agent may use an amine compound, and the main material is acrylic resin. In the case of, an isocyanate compound can be used as the curing agent.

In one example, the resin composition may be a two-component urethane-based composition. The two-part urethane-based composition may include a main material containing at least a polyol resin and a curing agent containing at least an isocyanate. Accordingly, the cured product of the resin composition may include both the polyol-derived unit and the polyisocyanate-derived unit. In this case, the polyol-derived unit may be a unit formed by urethane reaction of a polyol with a polyisocyanate, and the polyisocyanate-derived unit may be a unit formed by urethane reaction of a polyisocyanate and a polyol.

In one example, an ester polyol resin may be used as the polyol resin included in the subject matter. In the case of using an ester polyol, it is advantageous in securing excellent adhesion and adhesion reliability in the battery module after curing the resin composition.

Meanwhile, the ester polyol may be amorphous or a polyol having sufficiently low crystallinity. As used herein, the meaning of the term “amorphous” is known to those skilled in the art. For example, "amorphous" refers to a case where the crystallization temperature (Tc) and melting temperature (Tm) are not observed in the DSC (Differential Scanning calorimetry) analysis described later. At this time, the DSC analysis can be performed within the range of -80 to 60°C at a rate of 10°C/min, for example, heating from 25°C to 60°C at the rate and then reducing the temperature to -80°C, It can be made in a manner of raising the temperature to 60 ℃ again. In addition, "sufficiently low crystallinity" in the above means that the melting point (Tm) observed in the DSC analysis is less than 15°C, about 10°C or less, 5°C or less, 0°C or less, -5°C or less, -10 It means the case of about -20℃ or less. At this time, the lower limit of the melting point is not particularly limited, but, for example, the melting point may be about -80°C or higher, -75°C or higher, or about -70°C or higher. When the polyol is crystalline or does not satisfy the above melting point range, when crystallinity is strong (at room temperature), the difference in viscosity according to temperature tends to be large, so in the process of mixing the filler and the resin, the dispersion of the filler and the viscosity of the final mixture It may adversely affect the process, deteriorate processability, and as a result, it may be difficult to satisfy the cold resistance, heat resistance, and water resistance required in the two-component resin composition for a battery module.

In one example, as the ester polyol, for example, a carboxylic acid polyol or caprolactone polyol may be used.

The carboxylic acid polyol may be formed by reacting a component including a carboxylic acid and a polyol (ex. diol or triol, etc.), and the caprolactone polyol includes caprolactone and a polyol (ex. diol or triol, etc.) It can be formed by reacting a component. In this case, the carboxylic acid may be a dicarboxylic acid.

In one example, the polyol may be a polyol represented by Formula 1 or 2 below.

[Formula 1]

[Formula 2]

In Formulas 1 and 2, X is a unit derived from a carboxylic acid, and Y is a unit derived from a polyol. The unit derived from the polyol may be, for example, a triol unit or a diol unit. In addition, n and m may be any number, for example, n is a number in the range of 2 to 10, m is a number in the range of 1 to 10, R ₁ and R ₂ are each independently carbon number 1 to 14 It is an alkylene within the range of.

The term “carboxylic acid-derived unit” used herein may mean a portion of a carboxylic acid compound excluding a carboxyl group. Similarly, the term “polyol-derived unit” used herein may mean a portion of the polyol compound structure excluding a hydroxy group.

That is, when the hydroxy group of the polyol and the carboxyl group of the carboxylic acid react, the water (H ₂ O) molecule is desorbed by the condensation reaction, thereby forming an ester bond. When the carboxylic acid forms an ester bond by the condensation reaction as described above, the carboxylic acid-derived unit may mean a portion of the carboxylic acid structure that does not participate in the condensation reaction. In addition, the polyol-derived unit may mean a portion of the polyol structure that does not participate in the condensation reaction.

In addition, Y in Formula 2 also represents a portion excluding the ester bond after the polyol forms an ester bond with caprolactone. That is, in Formula 2, the polyol-derived unit, Y, may mean a portion of the polyol structure that does not participate in the ester bond when the polyol and caprolactone form an ester bond. Ester bonds are represented in Formulas 1 and 2, respectively.

On the other hand, when the polyol-derived unit of Y in the above formula is a unit derived from a polyol containing three or more hydroxy groups, such as a triol unit, a branched structure may be implemented in the Y portion of the formula.

In Formula 1, the type of the carboxylic acid-derived unit of X is not particularly limited, but in order to secure the desired physical properties, a fatty acid compound, an aromatic compound having two or more carboxyl groups, an alicyclic compound having two or more carboxyl groups, and 2 It may be a unit derived from one or more compounds selected from the group consisting of aliphatic compounds having two or more carboxyl groups.

The aromatic compound having two or more carboxyl groups may be, for example, phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, or tetrachlorophthalic acid.

The alicyclic compound having two or more carboxyl groups may be, for example, tetrahydrophthalic acid or hexahydrophthalic acid tetrachlorophthalic acid.

In addition, the aliphatic compound having two or more carboxyl groups is, for example, oxalic acid, adipic acid, azelaic acid, sebacic acid, succinic acid, malic acid, glutaric acid, malonic acid, pimelic acid, suberic acid, 2,2-dimethyl It may be succinic acid, 3,3-dimethylglutaric acid, 2,2-dimethylglutaric acid, maleic acid, fumaric acid or itaconic acid.

In consideration of the low glass transition temperature in the range described below, units derived from aliphatic carboxylic acids may be preferable to units derived from aromatic carboxylic acids.

On the other hand, the type of the polyol-derived unit of Y in Formulas 1 and 2 is not particularly limited, but in order to secure the desired physical properties, in the group consisting of an alicyclic compound having two or more hydroxy groups and an aliphatic compound having two or more hydroxy groups It may be derived from one or more compounds of choice.

The alicyclic compound having two or more hydroxy groups may be, for example, 1,3-cyclohexanedimethanol or 1,4-cyclohexanedimethanol.

In addition, the aliphatic compound having two or more hydroxy groups is, for example, ethylene glycol, propylene glycol, 1,2-butylene glycol, 2,3-butylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, 1,2-ethylhexyldiol, 1,5-pentanediol, 1,9-nonanediol, 1,10-decanediol, glycerin or trimethylol It can be propane.

Meanwhile, in Formula 1, n is an arbitrary number, and the range may be selected in consideration of the desired physical properties of the resin composition or the resin layer, which is a cured product thereof. For example, n may be about 2 to 10 or 2 to 5.

In addition, in Formula 2, m is an arbitrary number, and the range may be selected in consideration of the desired physical properties of the resin composition or the cured resin layer. For example, m is about 1 to 10 or 1 to 5 days. I can.

When n and m in Formulas 1 and 2 are out of the above range, crystallinity expression of the polyol increases and may adversely affect the injection processability of the composition.

In Formula 2, R ₁ and R ₂ are each independently alkylene having 1 to 14 carbon atoms. The number of carbon atoms may be selected in consideration of the desired physical properties of the resin composition or the resin layer, which is a cured product thereof.

The molecular weight of the polyol may be adjusted in consideration of viscosity, durability, or adhesion, and may be, for example, in the range of about 300 to 2,000. Unless otherwise specified, in the present specification, the "molecular weight" may be a weight average molecular weight (Mw) measured using a Gel Permeation Chromatograph (GPC). If it is out of the above range, the reliability of the resin layer after curing may be poor, or problems related to volatile components may occur.

In the present application, the type of isocyanate included in the curing agent is not particularly limited, but a non-aromatic isocyanate compound not containing an aromatic group may be used to secure desired physical properties. In the case of using an aromatic polyisocyanate, since the reaction rate is too fast and the glass transition temperature of the cured product may be increased, it may be difficult to secure fairness and physical properties suitable for use of the resin composition.

Examples of the non-aromatic isocyanate compound include aliphatic polyisocyanates such as hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, lysine diisocyanate, norbornane diisocyanate methyl, ethylene diisocyanate, propylene diisocyanate or tetramethylene diisocyanate. ; Alicyclic polyisocyanates such as transcyclohexane-1,4-diisocyanate, isophorone diisocyanate, bis(isocyanate methyl)cyclohexane diisocyanate or dicyclohexylmethane diisocyanate; Or any one or more of the above carbodiimide-modified polyisocyanates or isocyanurate-modified polyisocyanates; Etc. can be used. In addition, a mixture of two or more of the compounds listed above may be used.

Meanwhile, the resin component included in the two-part resin composition may have a glass transition temperature (Tg) of less than 0°C after curing. When the glass transition temperature range is satisfied, brittle characteristics can be secured within a relatively short time even at a low temperature in which the battery module or battery pack can be used, thereby ensuring impact resistance and vibration resistance. I can. On the other hand, when the above range is not satisfied, there is a possibility that tacky of the cured product is too high or thermal stability is deteriorated. In one example, the lower limit of the glass transition temperature of the two-part resin composition after curing may be about -70°C or more, -60°C or more, -50°C or more, -40°C or more, or about -30°C or more, and the The upper limit may be about -5°C or less, -10°C or less, -15°C or less, or about -20°C or less.

Meanwhile, the ratio of the polyol-derived resin component and the polyisocyanate-derived resin component in the two-part resin composition is not particularly limited, and may be appropriately adjusted to enable a urethane reaction therebetween.

Meanwhile, the resin composition may include a filler. The filler may be a thermally conductive filler. In the present application, the term thermally conductive filler may mean a material having a thermal conductivity of about 1 W/mK or more, 5 W/mK or more, 10 W/mK or more, or about 15 W/mK or more. Specifically, the thermal conductivity of the thermally conductive filler may be about 400 W/mK or less, 350 W/mK or less, or about 300 W/mK or less. The type of the thermally conductive filler that can be used is not particularly limited, but may be an inorganic filler in consideration of insulation and the like. For example, ceramic particles such as alumina, aluminum nitride (AlN), boron nitride (BN), silicon nitride, SiC or BeO may be used. The shape or ratio of the filler is not particularly limited, and the viscosity of the resin composition, the possibility of sedimentation in the cured resin layer, the desired heat resistance or thermal conductivity, insulation, filling effect, dispersibility or storage stability, etc. Can be adjusted appropriately in consideration. In general, as the size of the filler increases, the viscosity of the composition including the filler increases, and the likelihood that the filler precipitates in the resin layer to be described later increases. Also, as the size decreases, the thermal resistance tends to increase. Therefore, in consideration of the above points, a filler of an appropriate type and size may be selected, and if necessary, two or more fillers may be used together. In addition, it is advantageous to use a spherical filler in consideration of the amount to be filled, but a filler in a form such as a needle or plate may be used in consideration of network formation or conductivity.

In one example, the resin composition 30 may include a thermally conductive filler having an average particle diameter in the range of about 0.001 μm to 80 μm. The average particle diameter of the filler may be about 0.01 µm or more, 0.1 µm or more, 0.5 µm or more, 1 µm or more, 2 µm or more, 3 µm or more, 4 µm or more, 5 µm or more, or about 6 µm or more. In another example, the average particle diameter of the filler is about 75 µm or less, 70 µm or less, 65 µm or less, 60 µm or less, 55 µm or less, 50 µm or less, 45 µm or less, 40 µm or less, 35 µm or less, 30 µm or less, It may be 25 μm or less, 20 μm or less, 15 μm or less, 10 μm or less, or about 5 μm or less.

In order to obtain excellent heat dissipation performance, it may be considered that a thermally conductive filler is used in a high content. The filler may be used within a range of about 200 to about 2,000 parts by weight, based on 100 parts by weight of the total resin component of the resin composition, for example, a polyol resin and a polyisocyanate. Specifically, the content of the filler may be about 250 parts by weight or more, 300 parts by weight or more, 350 parts by weight or more, or about 400 parts by weight or more of a filler based on 100 parts by weight of the total resin component, and 100 parts by weight of the total resin component It may be about, 2,000 parts by weight or less, 1,800 parts by weight or less, or about 1,6000 parts by weight or less. Physical properties such as desired thermal conductivity and insulation may be secured within the ratio of the filler.

In one example, the moisture content of the filler may be about 1,000 ppm or less. The moisture content can be measured with a karl fishcer titrator (KR831) under conditions of a relative humidity of 10% and a drift of 5.0 or less. In this case, the moisture content may be an average moisture content of all fillers used in the resin composition. In the present application, a filler satisfying the above conditions may be selectively used, or after drying the filler to be used in an oven at a temperature of about 200° C., the moisture content of the filler may be adjusted to satisfy the moisture content range. In another example, the upper limit of the filler moisture content may be about 800 ppm or less, 600 ppm or less, or about 400 ppm or less, and the lower limit may be about 100 ppm or more or about 200 ppm or more.

In addition to the above, various types of fillers may be used. For example, in order to secure the insulating properties of the resin layer cured with the resin composition, use of a carbon filler such as graphite may be considered. Alternatively, for example, a filler such as fumed silica, clay or calcium carbonate may be used. The form or content ratio of the filler is not particularly limited, and may be selected in consideration of the viscosity of the resin composition, the possibility of sedimentation in the resin layer, thixotropy, insulation, filling effect, or dispersibility.

2 is a cross-sectional view illustrating a step of applying an exemplary curable material of the present application to an injection hole. The curable material 60 may be applied to the injection hole 20 formed in the lower plate 10a.

For application of the curable material, a known applicator can be used. The applicator 70 can apply a curable material onto the resin composition 30a of the injection hole 20.

The curable material 60 may include a resin and an initiator.

The resin is not particularly limited as long as it is a curable resin, and may be a known curable resin. As an example, the resin may be a photocurable resin. The photocurable resin may include polyester acrylate, epoxy acrylate, urethane acrylate, polyether acrylate, or silicone acrylate.

In the present application, the term photocurable refers to a type that is cured by irradiation of light, and in the category of light, microwaves, infrared (hereinafter, IR), ultraviolet (hereinafter, UV), X-rays and gamma rays, as well as , An alpha-particle beam, a proton beam, a neutron beam, or a particle beam such as an electron beam.

The curable material 60 may include an initiator, and the initiator may be a photo initiator. The photoinitiator may include at least one selected from the group consisting of acetophenone-based, benzoin-based, benzophenone-based, thioxanthone-based, iodonium-based, and sulfonium-based.

3 is a cross-sectional view showing an exemplary injection hole closing step of the present application. The light irradiator 80 irradiates light toward the curable material (60 in Fig. 2) applied to the injection hole 20 to cure the curable material (60 in Fig. 2) to cure the curing member (or sealing member) ( By forming 60a), the injection hole can be closed.

The light irradiator 80 is not particularly limited, and a known light irradiator capable of irradiating light may be used. The light is not particularly limited as long as it can be irradiated by a light irradiator such as infrared rays, visible rays, or ultraviolet rays, and for example, UV light may be used.

The light irradiation may be cured by irradiating light to the curable material 60 for about 5 to 15 seconds. In one embodiment, the light irradiation may be irradiated for about 5 seconds, 6 seconds, 7 seconds, or about 8 seconds or more, or about 15 seconds, 14 seconds, 13 seconds, or about 12 seconds or less.

When the curable material (60 in Fig. 2) is cured by light irradiation such as UV irradiation, a curing member 60a is formed, and the injection hole 20 is closed by the curing member 60a to cure resin It is possible to prevent the composition 30a from protruding to the outside of the battery module through the injection hole and curing due to residual pressure in the battery module. Accordingly, there is no need for an additional process to remove the cured portion protruding to the outside of the battery module, and thus the manufacturing cost and manufacturing time of the battery module may be reduced.

The battery module manufacturing method of the present application may further include a sheet attaching step of attaching an adhesive sheet to an injection hole formed on a lower plate or a sidewall before the resin composition injection step, and in the resin composition injection step, the resin composition includes the adhesive sheet It may penetrate through and be injected into the battery module case.

4 is a cross-sectional view showing a step of attaching an exemplary adhesive sheet 90 of the present application. The adhesive sheet 90 may be attached to the injection hole 20 formed in the lower plate 10a of the battery module case.

The adhesive sheet 90 may include a substrate and an adhesive layer formed on the substrate. The substrate is in the form of a polymer film having flexibility and durability, and may be selected from materials having high tensile strength. For example, the substrate may be polyolefin such as polyethylene or polypropylene, polyester such as polyethylene terephthalate or polybutylene terephthalate, polyvinyl chloride, polystyrene, polyurethane, polycarbonate, polyamide, polyimide, poly(meth) One or more selected from the group consisting of acrylic acid, polybutene, and polybutadiene may be mentioned, but the present invention is not limited thereto.

The adhesive layer formed on the substrate may include a material having adhesive properties so that the substrate is adhered to the battery module case. For example, the adhesive layer may be formed by applying an adhesive including acrylic, polyester, polyurethane, rubber, silicone, or epoxy on a substrate, or an adhesive film formed from the adhesive is attached to the substrate.

The adhesive sheet 90 may be attached to the injection hole 20. The meaning of being attached to the injection hole 20 may be attached in a form that covers the injection hole 20 beyond the size of the injection hole 20. In addition, when one or more injection holes 20 are provided, an individual adhesive sheet 90 corresponding to each injection hole 20 may be attached, and one adhesive sheet 90 covering all of the one or more injection holes 20 ) Can be attached. That is, in an exemplary embodiment, when a plurality of injection holes 20 are arranged and formed in an arbitrary direction, one adhesive sheet 90 may be attached to extend along the arrangement direction of the injection holes 20.

Meanwhile, in the resin composition injection step, the resin composition 30 may penetrate through the adhesive sheet 90 and be injected into the battery module case.

Injecting into the battery module case through the adhesive sheet 90 means that the adhesive sheet 90 attached to the injection hole 20 formed in the lower plate 10a or the side wall 10b of the battery module case is opened and injected before injection. Alternatively, it can be injected by opening at the same time as the injection.

Opening the adhesive sheet 90 before injection means that the portion of the adhesive sheet 90 corresponding to the injection hole 20 is opened before attaching the adhesive sheet 90 to the injection hole 20 and then attached. Alternatively, after attaching the adhesive sheet 90 to the injection hole 20, the opening may be performed by drilling a portion corresponding to the injection hole 20. On the other hand, the method of opening the adhesive sheet 90 is not particularly limited, and may be opened by a known method.

The fact that the pressure-sensitive adhesive sheet 90 is opened simultaneously with the injection means that the injection device (40 in Fig. 1) for injecting the resin composition 30 is positioned in the injection hole 20 to inject the resin composition 30. The injector 40 may open the adhesive sheet by applying a constant pressure to the adhesive sheet 90 attached to the injection hole 20. At this time, one end (not shown) of the injector 40 may be sharply formed to facilitate the opening of the adhesive sheet 90.

Meanwhile, as long as the injector 40 penetrates the adhesive sheet 90 and can be easily injected into the injection hole 20, the size and shape of the opening of the adhesive sheet 90 are not particularly limited. For example, the size of the opening of the adhesive sheet 90 may be equal to or smaller than the size of the injection hole. If the adhesive sheet 90 is the same as or smaller than the size of the injection hole, contamination of the battery module can be prevented even if the resin composition is discharged back.

The battery module manufacturing method of the present application may further include a sheet peeling step of peeling the adhesive sheet attached to the injection hole before the injection hole closing step.

5 is a cross-sectional view showing a step of peeling an exemplary adhesive sheet of the present application. That is, the adhesive sheet 90 attached to the injection hole 20 of the lower plate 10a may be peeled off from the lower plate.

The method of peeling the adhesive sheet is not particularly limited. It can be peeled manually by a person, or it can be peeled automatically by a machine.

On the other hand, peeling of the adhesive sheet may be peeled after about 1 hour to about 4 hours have elapsed after the resin composition is injected into the battery module case. That is, after curing of the resin composition proceeds for a predetermined time or longer, the adhesive sheet is peeled. The peeling time may be controlled by the type of resin composition. That is, when the resin composition is cured quickly, the peeling of the adhesive sheet may be accelerated, and when the resin composition is cured slowly, the peeling of the adhesive sheet may be delayed. If the adhesive sheet is peeled off before the resin composition is sufficiently cured, the battery module may be contaminated because the uncured resin composition comes out on the adhesive sheet. If the resin composition is peeled off after curing, adhesion between the resin composition and the adhesive sheet It may not be easy to peel.

The present application also relates to a battery module. 6 is a cross-sectional view showing an exemplary battery module of the present application. The battery module has a lower plate 10a and a side wall 10b, an inner space is formed by the lower plate 10a and the side wall 10b, and the resin composition formed on the lower plate 10a or the side wall 10b is injected. A module case having a hole 20; A plurality of battery cells 50 present in the inner space of the module case; A resin layer (30b) formed by curing the resin composition and in contact with at least one of the plurality of battery cells, lower plates, and sidewalls; And a sealing member 60a for sealing the injection hole of the resin composition.

The battery module case may be in the form of a box including one lower plate 10a and four side walls 10b. The battery module case forms an internal space by the lower plate 10a and the four side walls 10b. The battery module case may further include an upper plate (not shown) for sealing the inner space. The terms "upper plate" and "lower plate" may be used interchangeably according to the reference direction.

The battery module case may be formed by an integral lower plate 10a and sidewall 10b, or may be formed by assembling a separate lower plate 10a, sidewall 10b and/or upper plate (not shown). The shape and size of the module case is not particularly limited, and may be appropriately selected according to the purpose of the module case, the shape and number of battery cells accommodated in the internal space, and the like.

The battery module case may be a thermally conductive case. The term thermally conductive case refers to a case having a thermally conductive region having a thermal conductivity of 10 W/mk or more, or at least as described above. For example, at least one of the above-described side wall 10b, lower plate 10a, and upper plate (not shown) may have the thermally conductive region. In another example, the lower plate 10a and the sidewall 10b may include the thermally conductive region at a portion in contact with a resin layer, which will be described later, formed by the injected resin composition. In the above, the thermal conductivity is about 20 W/mk or more, 30 W/mk or more, 40 W/mk or more, 50 W/mk or more, 60 W/mk or more, 70 W/mk or more, 80 W/mk More than 90 W/mk, more than 100 W/mk, more than 110 W/mk, more than 120 W/mk, more than 130 W/mk, more than 140 W/mk, more than 150 W/mk, more than 160 W/mk, 170 W/mk or more, 180 W/mk or more, 190 W/mk or more, or about 195 W/mk or more. The higher the thermal conductivity, the higher the value is, the more advantageous it is in terms of heat dissipation characteristics of the module, and so the upper limit thereof is not particularly limited. In one example, the thermal conductivity is about 1,000 W/mK or less, 900 W/mk or less, 800 W/mk or less, 700 W/mk or less, 600 W/mk or less, 500 W/mk or less, 400 W/mk or less, It may be 300 W/mk or less than about 250 W/mK, but is not limited thereto. The type of material exhibiting the above thermal conductivity is not particularly limited, and examples thereof include metal materials of iron, aluminum, gold, silver, tungsten, copper, nickel, platinum, or alloys containing them.

In addition, the thermally conductive region may be a portion in contact with a cooling medium such as cooling water. According to this structure, a structure capable of effectively discharging heat generated from the battery cell to the outside can be implemented.

Meanwhile, in the case where the measured temperature affects the physical properties among the physical properties mentioned in the present specification, the physical properties may be the physical properties measured at room temperature unless otherwise stated. In the present specification, the term room temperature may mean any temperature within the range of about 10°C to 30°C, for example, about 25°C, 23°C, or about 20°C.

The lower plate 10a, the side wall 10b, and/or the upper plate (not shown) (hereinafter may be referred to as a lower plate or the like) of the battery module case has an injection hole 20 (or a through hole). At this time, the shape, number and position of the injection holes 20 may be adjusted in consideration of injection efficiency of the resin composition.

The injection hole 20 may be formed in the side wall 10b, the lower plate 10a, or the upper plate (not shown). The position Q of the injection hole may be formed at about 1/4 to 3/4 point, about 3/8 to 7/8 point, or about the middle part of the total length of the lower plate. By injecting the resin composition through the injection hole 20 formed at the point, the injection time of the resin composition can be shortened, and the resin composition can be evenly injected into the battery module. In a specific embodiment, the resin composition injected through the injection hole 20 moves along the injection (or movement) direction of the resin composition.

The point of 1/4, 3/4, 3/8 or 7/8 is the formation of the injection hole 20 compared to the total length L of the lower plate, etc., measured based on any one end surface of the lower plate, etc. It is the ratio of the distance (A) to the location. In addition, the end at which the length (L) and distance (A) are formed in the above may be any end as long as the length (L) and the distance (A) are measured from the same end.

In the present application, the term battery cell 50 refers to a single unit secondary battery including an electrode assembly and an exterior material.

The type of the battery cell 50 accommodated in the battery module case is not particularly limited, and various known battery cells may be applied. In one example, the battery cell 50 may be a pouch type.

Meanwhile, the resin layer 30b may be a resin layer 30b formed by curing the resin composition 30 described above. The resin layer 30b may be a thermally conductive resin layer. In this case, the thermal conductivity of the thermally conductive resin layer may be about 1.5 W/mK or more, 2 W/mK or more, 2.5 W/mK or more, 3 W/mK or more, 3.5 W/mK or more, or about 4 W/mK or more. . The thermal conductivity is about 50 W/mK or less, 45 W/mk or less, 40 W/mk or less, 35 W/mk or less, 30 W/mk or less, 25 W/mk or less, 20 W/mk or less, 15 W/ mk or less, 10 W/mK or less, 5 W/mK or less, 4.5 W/mK or less, or about 4.0 W/mK or less. When the resin layer is a thermally conductive resin layer as described above, the lower plate, the upper plate, and/or the sidewall to which the resin layer is attached may be a portion having a thermal conductivity of 10 W/mK or more. In this case, the portion of the module case indicating the thermal conductivity may be a portion in contact with a cooling medium, for example, cooling water. The thermal conductivity of the resin layer is a value measured according to, for example, ASTM D5470 standard or ISO 22007-2 standard. The thermal conductivity of the resin layer as described above can be secured, for example, by appropriately adjusting the filler contained in the resin layer and the content ratio thereof as described above.

The sealing member 60a is not particularly limited as long as it can seal the injection hole 20. The sealing member may be of a forming type or a combined type. In the present application, the term forming type means anything formed on the cured resin composition 30a of the injection hole to seal the injection hole. As an example, the forming sealing member may seal the injection hole 20 by applying and curing the above-described curable material 60 to the injection hole.

On the other hand, in the present application, the term combined type refers to anything other than a forming type, and for example, may refer to a sealing member manufactured separately. In one embodiment, the injection hole may be sealed by a method such as fastening a separately manufactured sealing member to the injection hole.

The present application also relates to a battery pack, for example, a battery pack including two or more of the aforementioned battery modules. In the battery pack, the battery modules may be electrically connected to each other. A method of configuring a battery pack by electrically connecting two or more battery modules is not particularly limited, and all known methods may be applied.

The present application also relates to the battery module or to a device comprising the battery pack. An example of the device may be a vehicle such as an electric vehicle, but the present invention is not limited thereto, and any application requiring a secondary battery as an output may be included. For example, a method of configuring the vehicle using the battery module or battery pack is not particularly limited, and a general method may be applied.

In the method of manufacturing a battery module of the present application, when the resin composition is cured, it is possible to prevent the resin composition from protruding to the outside of the battery module through an injection hole due to residual pressure in the battery module and curing. In addition, in the manufacturing method of the battery module of the present application, since an additional process for removing the cured portion protruding to the outside of the battery module is unnecessary, the production cost of the battery module can be reduced, and the production time can be shortened. In addition, even if the residual pressure in the battery module is high, it is possible to prevent the resin composition from protruding to the outside of the battery module and curing.Therefore, a resin composition that may protrude out of the battery module under the influence of the residual pressure can also be used as a resin composition for a battery module. It is possible.

1 is a cross-sectional view showing an exemplary resin composition injection step of the present application.
2 is a cross-sectional view showing a step of applying an exemplary curable material of the present application.
3 is a cross-sectional view showing an exemplary injection hole closing step of the present application.
4 is a cross-sectional view illustrating a step of attaching an exemplary adhesive sheet of the present application.
5 is a cross-sectional view illustrating a step of peeling an exemplary adhesive sheet of the present application.
6 is a cross-sectional view illustrating an exemplary battery module of the present application.
7 is a schematic diagram showing a method of manufacturing an exemplary battery module of the present application.

7 is a schematic diagram illustrating a method of manufacturing an exemplary battery module of the present application. Hereinafter, examples and comparative examples will be described with reference to FIG. 7, but the scope of the present application is not limited by the ranges presented below.

Assessment Methods

One. Whether reverse discharge

The resin composition was injected through an injection hole formed in the lower plate of the battery module case in which the plurality of battery cells were accommodated. The resin composition was injected through an injection hole formed in the lower plate after the lower plate was positioned upward.

Resin composition through the injection hole formed in the lower plate due to the weight of the battery cell when the injected resin composition is discharged back to the top through the injection hole due to the residual pressure in the battery module during curing or when the battery module is turned upside down immediately after injection It was evaluated whether this was discharged back.

<Evaluation result>

○: In case of reverse discharge

X: If reverse discharge is not possible

2. Fairness

Even when the reverse discharge of the resin composition is prevented, the process of removing the adhesive sheet after attaching it to the injection hole is required twice to prevent the above, or a process of manually sealing the injection hole is required, or additional processes such as heat treatment are required. It was evaluated that the fairness suitable for the automated process was not secured in the case where it is required that it is not suitable for the automated process or the manufacturing time is exemplified that it will take an excessively long time.

<Evaluation result>

○: When it is suitable for application of an automated process

X: In case of unsuitable for application of automated process

Example To Comparative example

Example

A battery module was manufactured through the following steps S1 to S6.

Step S1: The adhesive sheet was attached to the injection hole formed in the lower plate of the battery module case in which the plurality of battery cells were accommodated.

Step S2: Two-part urethane-based resin composition (subject: HP-3753 (KPX Chemical), curing agent: TLA-100 (Asaika)) in alumina (particle size distribution: 1㎛ to 60㎛), the two-part urethane-based resin composition is cured After mixing in an amount capable of showing a thermal conductivity of about 3 W/mK (within the range of about 600 to 900 parts by weight based on 100 parts by weight of the total solid content), 0.01 to 10.0/ using a rheological property meter (ARES) at room temperature When measured in the range of shear rate up to s, a resin composition having a viscosity of about 250,000 cP measured at a point of 2.5/s was prepared, and it was injected through the injection hole.

Step S3: The resin composition injected into the battery module was cured for 80 minutes.

Step S4: After curing for 80 minutes, the adhesive sheet attached to the injection hole was removed.

Step S5: A photocurable polyurethane-based resin and photoinitiator (TPO (Diphenyl (2,4,6-trimethylbenzoyl)-phosphine oxide)) with a weight average molecular weight (Mw) of 500 or more with a curable resin on the injection hole from which the adhesive sheet is peeled off. A curable material containing a was applied.

Step S6: Ultraviolet (UV) rays were irradiated for 10 seconds on the area to which the curable material was applied.

Comparative example One

Among steps S1 to S6 of the embodiment, a battery module was manufactured only in steps S2 and S3.

Comparative example 2

After the steps S1 to S4 of the example were performed, an adhesive sheet having no opening was attached to the injection hole, and the adhesive sheet was removed after curing the resin composition.

Comparative example 3

After the steps S1 to S4 of the embodiment were performed, the injection hole was sealed using a stopper.

Comparative example 4

After performing the steps S1 to S4 of the example, the injection hole portion was heated to a temperature of 50 °C or less.

fair Presence of reverse discharge Fairness Example UV irradiation X ○ Comparative Example 1 none ○ X Comparative Example 2 Attach the adhesive sheet to the injection hole
Removal after curing the resin composition X X
(2 processes required) Comparative Example 3 The injection hole is sealed with a stopper X X
(Difficulty in automation process) Comparative Example 4 Heating the injection hole ○ X
(It takes a long time to cure)

From Table 1, in the battery module of the embodiment manufactured by the method of manufacturing the battery module of the present application, after removing the adhesive sheet, a curable material was applied to the injection hole and irradiated with UV to prevent the resin composition from being discharged back and curing. Therefore, there is no need for an additional process for removing the protruding and curing resin composition, and since the curable material is cured in a short time, the manufacturing time per battery module is shortened, making it suitable for application of an automated process.

In contrast, in Comparative Example 1, the resin composition was discharged back, and Comparative Examples 2 and 3 were not cured because the resin composition was discharged back, but to prevent this, Comparative Example 2 attached an adhesive sheet to the injection hole and cured the resin composition. The process of removing after attaching is necessary, and the process of removing after attaching the adhesive sheet requires two times in the battery module manufacturing process, so fairness is poor, and in Comparative Example 3, the injection hole must be manually sealed using a stopper. The battery cell could be pressurized by this, making it unsuitable for automated process applications. On the other hand, in Comparative Example 4, the viscosity of the resin composition was lowered by heating, so when the battery module was turned upside down immediately after injection of the resin composition, the resin composition was better discharged back, and the resin composition was sufficiently cured to support the weight of the battery cell. Since it took a long time to do, it took a long time to manufacture each battery module, which was unsuitable for the application of the automated process of the battery module.

10a: lower plate
10b: side wall
20: injection hole
30: resin composition
30a: resin composition to be cured
30b: resin layer
40: injector
50: battery cell
60: curable material
60a: hardening member, sealing member
70: curable material applicator
80: light irradiator
90: adhesive sheet

Claims (15)

A resin composition injection step of injecting a resin composition into the battery module case through an injection hole formed in a lower plate or sidewall of the battery module case in which the plurality of battery cells are accommodated; And
A method of manufacturing a battery module comprising the step of closing an injection hole for curing by applying a curable material to the injection hole. The method of claim 1, wherein the resin composition is a two-component composition comprising a main material and a curing agent. The method of claim 2, wherein the resin composition further comprises an inorganic filler. The method of claim 1, wherein the curable material applied to the injection hole is photo-curable. The method of claim 4, wherein the curable material comprises a resin and an initiator. The method of claim 5, wherein the initiator is at least one selected from the group consisting of acetophenone-based, benzoin-based, benzophenone-based, thioxanthone-based, iodonium-based, and sulfonium-based. The method of claim 1, wherein the curing of the curable material is performed by irradiating light for 5 to 15 seconds. The battery module of claim 1, further comprising a sheet attaching step of attaching an adhesive sheet to the injection hole before the resin composition injection step, wherein in the resin composition injection step, the resin composition penetrates the adhesive sheet and is injected into the battery module case. Manufacturing method. The method of claim 8, further comprising a sheet peeling step of peeling off the adhesive sheet attached to the injection hole before the closing step of the injection hole. The method of claim 9, wherein the adhesive sheet has an opening at a position corresponding to the injection hole. A module case having a lower plate and a side wall, an inner space formed by the lower plate and the side wall, and having an injection hole of the resin composition formed in the lower plate or the side wall;
A plurality of battery cells present in the inner space of the module case;
A resin layer formed by curing the resin composition and in contact with at least one of the plurality of battery cells, the lower plate, and the sidewall; And
Battery module comprising a sealing member for sealing the injection hole of the resin composition. The battery module according to claim 11, wherein the resin layer has a thermal conductivity of 3.0 W/mK or more. The battery module according to claim 11, wherein the sealing member is a cured product of a photocurable resin. A battery pack comprising two or more battery modules of claim 11 that are electrically connected to each other. A vehicle comprising the battery module of claim 11 or the battery pack of claim 14.

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