Battery assembly

Abstract

A battery assembly is provided, including a battery case, a battery cell assembly including a plurality of battery cells stacked and placed in the case and electrically connected, and a heat dissipation resin layer, and by controlling physical properties of the low-hardness heat dissipation resin layer, the battery cell assembly minimizes damage to the battery cells due to an expansion phenomenon occurring in the battery cells and improves module life.

Description

Technical Field

[0001] The technology and implementation methods disclosed in this patent document generally relate to a battery assembly including a low-hardness heat-dissipating resin layer. Background Technology

[0002] A battery assembly may include multiple battery cells that are electrically connected and housed within a casing. The rapid growth of electric vehicles, hybrid vehicles, and energy storage systems (ESS) has led to a demand for battery assemblies with high energy density. Summary of the Invention

[0003] The disclosed technology can be implemented in some embodiments to effectively release heat from the battery cells and battery assembly by using a heat-dissipating resin layer with specific physical properties, and to minimize potential damage to the battery cells in the battery assembly during the expansion phenomenon that occurs in the battery cells during charging and discharging of the battery cells.

[0004] The disclosed technology can be implemented in some embodiments to provide a battery assembly including a low-hardness heat-dissipating resin layer disposed between the battery cells and the battery casing to suppress battery cell flow that may be caused by vibration and external impact in normal driving conditions, thereby minimizing potential damage to the battery cells in the battery assembly.

[0005] In one general aspect, a battery assembly includes: a battery housing comprising at least one housing plate or housing wall; a battery cell assembly comprising a plurality of battery cells stacked and disposed within the housing and electrically connected; and a heat-dissipating resin layer disposed between the at least one housing plate and the battery cell assembly, wherein the heat-dissipating resin layer has an adhesive shear strength of 0.2 MPa or greater as measured according to ASTM D1002 and satisfies the following formula:

[0006] [Formula 1]

[0007]

[0008] Wherein, A is the softness index of the heat-dissipating resin layer, E is the elastic modulus of type 4 according to ASTM D638-14 at a tensile speed of 5 mm / min, and L is the elongation of type 4 according to ASTM D638-14 at a tensile speed of 5 mm / min.

[0009] In an example embodiment of the disclosed technology, the heat-dissipating resin layer may have an elastic modulus of 1 to 20 MPa as measured according to ASTM D638-14.

[0010] In an example embodiment of the disclosed technology, the heat-dissipating resin layer may have an elongation of 30% to 450% as measured according to ASTM D638-14.

[0011] In an example embodiment of the disclosed technology, the heat-dissipating resin layer may have an adhesive shear strength of 0.2 to 5.0 MPa as measured according to ASTM D1002.

[0012] In exemplary embodiments of the disclosed technology, the heat-dissipating resin layer may have a Shore A hardness of 40 to 75, as measured according to ASTM D2240. In some embodiments, the term "Shore A hardness" may be used to indicate a hardness value obtained using a Shore (hardness tester).

[0013] In exemplary embodiments of the disclosed technology, the heat-dissipating resin layer may include at least one selected from the group consisting of: urethane resins, epoxy resins, silicone resins, acrylic resins, olefin resins, and ethylene-vinyl acetate (EVA) based resins.

[0014] In an example embodiment of the disclosed technology, the heat-dissipating resin layer may have a thermal conductivity of 1 to 3 W / mK.

[0015] In exemplary embodiments of the disclosed technology, the heat-dissipating resin layer may include at least one thermally conductive filler selected from the group consisting of: aluminum oxide, aluminum hydroxide, silicon nitride, zinc oxide, magnesium oxide, boron nitride (BN), aluminum nitride (AlN), and silicon carbide (SiC).

[0016] In example embodiments of the disclosed technology, the value of A may be 2.1 or less.

[0017] In an example embodiment of the disclosed technology, the housing may include at least one plate selected from an upper plate, a lower plate, a side plate, and an end plate.

[0018] In an example embodiment of the disclosed technology, the battery cell may be pouch-shaped.

[0019] In example embodiments of the disclosed technology, the battery assembly may be a battery module or a battery pack.

[0020] Other features and aspects will become clear from the following detailed description, drawings and claims. Attached Figure Description

[0021] Figure 1 This is a perspective view showing a battery module including a heat-dissipating resin layer and battery cells.

[0022] Figure 2 This is a perspective view of a battery pack, including a heat-dissipating resin layer and battery cells. Detailed Implementation

[0023] The chapter headings used in this document are for ease of understanding only and do not limit the scope of the embodiments to the chapters in which they are described.

[0024] In the following, a battery assembly including a low-hardness heat-dissipating resin layer, based on some embodiments of the disclosed technology, will be described in detail with reference to the accompanying drawings.

[0025] In some embodiments discussed in this patent document, units associated with weight may be used without mentioning their association with weight. As an example, the unit of ratio, or %, may be used to express wt% or weight ratio. wt% refers to the weight percentage of a component in the composition relative to the weight of the composition.

[0026] In some embodiments discussed in this patent document, the numerical range may include all values ​​within that range, including lower and upper limits, logically deducible increments, and all possible combinations of upper and lower limits in numerical ranges defined in different forms. Unless otherwise specified in this patent document, values ​​outside the defined numerical range (e.g., due to experimental error or rounding) may also be included within the defined numerical range.

[0027] In some implementations, the term "thermal heat dissipation resin layer" may be used in the same sense as the terms "thermal heat dissipation adhesive layer" or "thermal conductive adhesive layer".

[0028] In some embodiments, the term "battery assembly" may be used to refer to a battery module or battery pack. In some embodiments, the term "battery module" may be used to refer to a battery assembly comprising multiple battery cells. In some embodiments, the term "battery pack" may be used to refer to a battery assembly comprising multiple battery modules, each of which comprises multiple battery cells.

[0029] The disclosed technology can be implemented in some embodiments to provide a battery module including a low-hardness heat-dissipating resin layer to improve surface pressure during expansion, thereby minimizing potential damage to the battery module and the battery assembly including the battery module, and ensuring vibration / shock stability.

[0030] In one embodiment of the disclosed technology, the battery assembly may include: a battery housing including at least one housing plate or housing wall; a battery cell assembly located within the battery housing and structured to include a plurality of battery cells electrically connected to each other and disposed within the battery housing; and a heat-dissipating resin layer disposed between at least one housing plate and the battery cell assembly. In some embodiments, the term "battery cell" may be used to refer to a battery cell that can convert chemical energy into electrical energy.

[0031] In some embodiments, the housing may include at least one plate selected from a top plate, a bottom plate, a side plate, and an end plate. In some embodiments, the term "plate" may be used to refer to a housing plate or housing wall that is part of the battery housing.

[0032] In this example, the housing is a module housing, and the housing may consist only of side panels. Here, the side panels may be connected to a strip, and a heat-dissipating resin layer may be placed between the battery pack and the battery cell assembly.

[0033] In this example, the housing is a module housing, and the housing may include side panels and a top panel. Here, a heat-dissipating resin layer may be placed between the battery pack and the battery cell assembly.

[0034] In the example, the housing is a module housing, and the housing may include side panels, a top panel, a bottom panel, and end panels. Here, a heat-dissipating resin layer may be placed between at least one of the following: between the side panels and the outermost battery cells of the battery cell assembly, between the battery cells inside the module and the bottom panel, and between the battery cells and the top panel.

[0035] In this example, the casing could be a battery pack casing. In this case, a heat-dissipating resin layer could be placed between the battery pack and the battery cells.

[0036] The heat-dissipating resin layer may be disposed on at least a portion of the surface in contact with the plate, and in some embodiments, it may be disposed on the entire surface.

[0037] In some embodiments, the battery assembly may also include a cooling device.

[0038] In some embodiments, in a battery module with a lower cooling structure (where the cooling device is placed in the lower portion of the module housing), the flow path of the cooling fluid may be formed in or on the lower housing plate in order to achieve electrical insulation properties and / or excellent heat transfer properties.

[0039] When battery modules have high energy density, high-speed charging / discharging operations can generate significant amounts of heat. If this heat is not controlled, safety issues arise. The disclosed techniques can be implemented in some embodiments to provide battery modules with excellent heat dissipation performance, allowing for rapid dissipation of heat generated within the battery module and effective heat dissipation to the outside.

[0040] In the example implementation, a thermally conductive adhesive with high hardness and excellent mechanical properties can be used as a heat dissipation component. However, there is a risk that the surface of the battery cell may be damaged during an expansion phenomenon, which causes the battery cell to expand during charging and discharging, thereby reducing battery life.

[0041] To address these issues, the disclosed technology can be implemented in some embodiments to provide a heat dissipation component configured to maintain the structural stability of the battery assembly and effectively release heat accumulated in the battery assembly during use.

[0042] Figure 1 An example configuration of a battery assembly 1000 is shown. This battery assembly 1000 may include a battery cell assembly 100 and a heat-dissipating resin layer 200 within a battery housing 300 for dissipating heat from the battery cell assembly 100. The battery cell assembly 100 may include multiple battery cells, such as rechargeable battery cells. The battery housing 300 may include a top plate 310, an end plate 320, a side plate 330, and a bottom plate 340. Figure 1 In the example shown, the heat-dissipating resin layer 200 may be disposed between the battery cell assembly 100 and the lower plate 340 of the battery casing 300. However, the heat-dissipating resin layer 200 is not limited to this example, and in another example, the heat-dissipating resin layer 200 may be disposed between the side plate 330 and the outermost battery cell of the battery cell assembly 100 and / or between the battery cell assembly 100 and the upper plate 310. In some embodiments, the heat-dissipating resin layer 200 may be disposed on a portion or all of the surface in contact with the battery cell. High-hardness (or high-strength) thermally conductive adhesives that can be used in battery modules may cause damage to the battery cells (e.g., the materials and structure inside the battery cells), which may ultimately lead to a shortened battery life. However, battery assemblies implemented based on some embodiments of the disclosed technology may include a heat-dissipating resin layer comprising a low-hardness heat-dissipating adhesive, thereby effectively dissipating the heat generated in each battery cell and minimizing damage to the battery. In this way, the lifespan and stability of the battery module can be improved.

[0043] Therefore, in some embodiments, the heat-dissipating resin layer has an adhesive shear strength of 0.2 MPa or greater as measured according to ASTM D1002, and can satisfy the following formula 1:

[0044] [Formula 1]

[0045]

[0046] Where A is the softness index of the heat-dissipating resin layer, E is the modulus of elasticity of type 4 according to ASTM D638-14 at a tensile speed of 5 mm / min, and L is the elongation of type 4 according to ASTM D638-14 at a tensile speed of 5 mm / min. In some embodiments, the term "ASTM" may be used to refer to technical standards published by the American Society for Testing and Materials (ASTM).

[0047] In some embodiments, in Formula 1, the softness index "A" of the heat-dissipating resin layer can be 2.1 or less, or 2.0 or less. When the softness index meets the numerical range described above, excellent heat dissipation and structural adhesion are achieved simultaneously, thereby preventing or minimizing potential external and internal damage to the battery cell, even in environments with external vibration or impact. In this way, battery life and stability can be improved.

[0048] Decreasing the elastic modulus of the thermally conductive resin layer can improve battery cycle life. However, since the elastic modulus corresponds to the volume change of the battery cell, and the thermally conductive resin layer is susceptible to vibration and shock, the range of the elastic modulus needs to be limited to a level that does not impair battery cycle life, thereby ensuring excellent durability. Furthermore, when both elongation and elastic modulus are low, the thermally conductive resin layer is highly likely to fracture, potentially negatively impacting the battery's structure and performance. Therefore, the range of elongation needs to be limited to a level that ensures excellent shock resistance without causing degradation of battery structure and performance. Thus, in some embodiments of the disclosed technology, the correlation between the elastic modulus and elongation is expressed as a softness index value A and can be appropriately controlled to provide a battery assembly including a thermally conductive resin layer with optimized physical properties. In this way, the disclosed technology can be implemented in some embodiments to provide a battery assembly with excellent durability, extended battery life, and improved stability while meeting predetermined shear strength values.

[0049] Furthermore, the heat-dissipating resin layer can have a Shore A hardness measured according to ASTM D2240, with a value less than 90 or less than 80, for example, a value ranging from 40 to 75. When the hardness is 90 or greater, 80 or greater, or greater than 75, the battery cells associated with the heat-dissipating resin layer may be easily damaged. By meeting the hardness value range described above, potential battery cell damage can be minimized, and the durability of the heat-dissipating resin layer can be ensured.

[0050] In exemplary embodiments, the thermally conductive adhesive composition included in the thermally conductive resin layer exhibits low hardness and can be an elastic composite formed by mixing a binder and filler, the binder comprising at least one of urethane resins, epoxy resins, acrylic resins, olefin resins, and ethylene-vinyl acetate (EVA)-based resins mixed in a polymeric manner. In some embodiments, the binder may be a urethane resin or a silicone resin, but the disclosed techniques are not limited thereto, provided that it satisfies the physical properties described below.

[0051] Urialkyl resins can be formed by mixing at least one hydroxyl-containing compound with an isocyanate. This uralkyl resin is a two-component polyurethane and can be distinguished from a one-component polyurethane having uralkyl groups in a single composition. Two-component polyurethanes can be produced by reacting and curing a base agent comprising at least one hydroxyl-containing compound and a curing agent selected from aliphatic isocyanates, alicyclic isocyanates, and aromatic isocyanates at room temperature. In some embodiments, the term "room temperature" can be used to indicate the state of the material without being specifically heated or cooled. In one example, room temperature can refer to a temperature in the range of 10°C to 30°C, such as 15°C or higher, 18°C ​​or higher, 20°C or higher, or 23°C or higher and 27°C or lower.

[0052] As an example, the curing reaction can be carried out using a catalyst such as dibutyltin dilaurate (DBTDL). A two-component polyurethane composition may include a physical mixture of a base component and a curing agent component, and may include the reaction products (cured products) of the base component and the curing agent component.

[0053] At least one hydroxyl-containing compound may be a monohydric alcohol, dihydric alcohol, trihydric alcohol, or polyhydric alcohol, and may be selected from, for example, from: dihydric alcohols, including ethylene glycol (EG), propylene glycol (PG), 1,3-butanediol (1,3-BD), 1,4-butanediol (1,4-BD), neopentyl glycol (NPG), diethylene glycol (DEG), 3-methyl-1,5-pentanediol (MPD), or 1,6-hexanediol (1,6-HD); trihydric alcohols, including trimethylolpropane (TMP) or glycerol; tetrahydric alcohols, including pentaerythritol; polyether polyhydric alcohols, including polyethylene glycol (PEG), polypropylene glycol (PPG), polypropylene triol (GP), or polybutylene glycol (PTMG); polyester polyhydric alcohols, which are condensation polymers of a basic acid including adipic acid, sebacic acid, or isophthalic acid with a dihydric alcohol, or polyester polyhydric alcohols including polycaprolactone polyhydric alcohols. More specifically, at least one hydroxyl-containing compound may be selected from: aromatic polyester polyols, such as condensation polymers of isophthalic acid and diol; and aliphatic polyester polyols, such as polycaprolactone polyol or poly(1,4-butanediol adipic acid).

[0054] In embodiments of the disclosed technology, at least one compound containing a hydroxyl group may be a polyether polyol or a mixture of polyether polyols. As a non-limiting example, it may include poly(tetramethylene glycol), polypropylene glycol, and variants thereof.

[0055] The isocyanate can be a polyfunctional isocyanate, such as a diisocyanate, a triisocyanate, etc., and can be an aliphatic, alicyclic, or aromatic isocyanate. In some embodiments, the isocyanate can be ethylene diisocyanate; hexamethylene-1,6-diisocyanate (HDI); isophorone diisocyanate (IPDI); 4,4'-dicyclohexylmethane diisocyanate, 2,2'-dicyclohexylmethane diisocyanate, and 2,4'-dicyclohexylmethane diisocyanate (H12MDI); norbornene diisocyanate; 1,3-(diisocyanate methyl)cyclohexane (including its cis or trans isomers) and 1,4-(diisocyanate methyl)cyclohexane (including its cis or trans isomers); tetramethylene-1,4-diisocyanate (TMXDI); 1,12-Dodecane diisocyanate; 2,2,4-Trimethylhexamethylene diisocyanate; 2,2'-Diphenylmethane diisocyanate (MDI), 2,4'-Diphenylmethane diisocyanate (MDI), and 4,4'-Diphenylmethane diisocyanate (MDI); carbodiimide-modified MDI; 2,4-Toluene diisocyanate (TDI) and 2,6-Toluene diisocyanate (TDI); 1,3-Phenylidene diisocyanate and 1,4-Phenylidene diisocyanate; 1,5-Naphthalene diisocyanate; Triphenylmethane-4,4',4”-Triisocyanate; or polymethylene polyphenyl polyisocyanate.

[0056] Silicon-based resins can refer to polymer compounds that include siloxane bonds as the main backbone. For example, a silicone-based resin can be a polydimethylsiloxane resin, or it can be produced by reacting and curing a main agent comprising a polydimethylsiloxane polymer and a curing agent at room temperature. For example, the polydimethylsiloxane polymer can be a divinylmethyl-terminated polydimethylsiloxane, and the curing agent can be a dimethylsiloxane-methylhydrosiloxane copolymer.

[0057] The filler is a thermally conductive filler and may include at least one selected from the group consisting of alumina, aluminum hydroxide, silicon nitride, zinc oxide, magnesium oxide, boron nitride (BN), aluminum nitride (AlN), and silicon carbide (SiC), as well as mixtures of one or more of alumina, aluminum hydroxide, silicon nitride, zinc oxide, magnesium oxide, BN, AlN, and SiC. The form or proportion of the filler is not particularly limited and can be adjusted taking into account the viscosity of the urethane resin composition, the likelihood of sedimentation in the cured resin layer of the composition, heat resistance, thermal conductivity, dispersibility, or other factors.

[0058] The heat-dissipating resin layer can be formed by curing a resin composition comprising a urethane resin mixed with the fillers described above, or a resin composition comprising a silicone resin mixed with the fillers, at room temperature for a certain period of time. In other embodiments, heat is applied for a period of time to a degree that promotes curing while maintaining the thermal stability of the battery cell. For example, heat at a temperature below 60°C, particularly in the range of 30°C to 50°C, can be applied before or during curing, before storing the battery cell, or during storage.

[0059] In an example embodiment, the heat-dissipating resin layer may include 10 to 150 parts by weight of a resin component and 100 parts by weight of a filler. In another example embodiment, the heat-dissipating resin layer may include 20 to 100 parts by weight of a resin component and 100 parts by weight of a filler.

[0060] In addition, the resin composition may also include, for example, viscosity modifiers for increasing or decreasing viscosity or adjusting viscosity according to shear strength, such as thixotropic agents, diluents, dispersants, surface treatment agents, and coupling agents.

[0061] The viscosity of the thixotropic agent can be adjusted according to the shear strength of the resin composition to allow for efficient completion of the battery module manufacturing process. In some embodiments, it can be calcined silica, etc.

[0062] Diluents or dispersants are commonly used to reduce the viscosity of resin compositions, and any type of diluent or dispersant can be used without limitation, as long as it exhibits the characteristics described above.

[0063] Surface treatment agents can be used to treat the surface of the filler introduced into the heat dissipation resin layer, and any type of surface treatment agent can be used without limitation.

[0064] Coupling agents can be used to improve the dispersibility of thermally conductive fillers such as alumina, and there are no restrictions on the type of coupling agent that can be used.

[0065] In other embodiments, the resin composition may also include a flame retardant or flame retardant additive. In this case, any type of flame retardant can be used without particular limitation, and specifically, for example, a flame retardant in the form of a solid filler or a liquid flame retardant can be used. The flame retardant can be an organic flame retardant such as melamine cyanurate, an inorganic flame retardant such as magnesium hydroxide, or others. When the amount of filler filling the heat-dissipating resin layer is large, liquid triethyl phosphate (TEP), tris(1,3-chloro-2-propyl) phosphate (TCPP), etc., can be used. Furthermore, a silane coupling agent that can act as a flame retardant reinforcing agent can be added.

[0066] The resin composition can have a viscosity of 100,000 cP to 500,000 cP as measured at room temperature.

[0067] In an example embodiment, the heat-dissipating resin layer including thermally conductive filler may have a thermal conductivity of 1 W / mK or higher, specifically from 1 W / mK to 3 W / mK, to increase the cooling efficiency of the battery cell in the cooling device.

[0068] The heat-dissipating resin layer based on some embodiments of the disclosed technology may also satisfy at least one of the following physical properties:

[0069] a) Elastic modulus of 1 to 20 MPa as measured according to ASTM D638-14;

[0070] b) Elongation of 30% to 450%, 40% to 300%, 50% to 250%, 80% to 230%, or 90% to 220% as measured according to ASTM D638-14; and

[0071] c) Adhesive shear strength of 0.2 to 5.0 MPa as measured according to ASTM D1002.

[0072] In some embodiments, a battery module or battery pack including a heat-dissipating resin layer that satisfies the physical properties discussed above can exhibit excellent structural stability even in the presence of external vibration and shock, and can improve surface pressure during expansion and prevent potential damage to the surface of the battery cells.

[0073] In example embodiments, the heat-dissipating resin layer may be disposed between the battery cell and the side panel of the casing, between the battery cell and the lower panel, or between the battery cell and the upper panel. In some embodiments, the thickness of the heat-dissipating resin layer is not limited, but may specifically be 0.1 to 20 mm, 0.2 to 10 mm, or 0.3 to 5 mm.

[0074] Figure 1 A heat-dissipating resin layer 200, in a coated state, is shown as an embodiment based on the disclosed technology, placed between a plurality of battery cells 100 and a lower plate 340 included in a battery assembly 1000.

[0075] The heat-dissipating resin layer 200 can provide at least one property, including insulation, adhesion and thermal conductivity, and in addition to Figure 1 In addition to the contents shown, the heat-dissipating resin layer 200 may be disposed between the outermost battery cell and the side panel of the housing, or between the top panel of the housing and the battery cell. In one example, the heat-dissipating resin layer 200 may have the following characteristics: Figure 1 The snake-like shape shown.

[0076] Figure 2Examples of configurations based on the disclosed technology are shown, in which a heat-dissipating resin layer is installed between a plurality of battery cells 100 and a battery pack included in a battery assembly 1000. In this case, a module-less or cell-to-pack method can be applied, and the heat-dissipating resin layer can be placed between at least one of the following: between the upper plate and the battery cells of the battery housing, between the lower plate and the battery cells, between the side plate and the battery cells, and between the end plate and the battery cells.

[0077] In some embodiments of the disclosed technology, an adhesive strength of 0.2 MPa or higher, or 0.5 MPa or higher, can be ensured. In some embodiments, the adhesive strength can be from 0.2 to 5.0 MPa, or from 0.5 to 3.0 MPa. In this case, various materials constituting components such as the housing, battery cells, and vehicle chassis of the battery assembly, battery module, and battery pack can exhibit excellent adhesive properties and prevent peeling of the heat-dissipating resin layer even when there are volume changes due to outgassing during the charging and discharging of the battery cells, thereby improving the durability of the battery assembly, battery module, and battery pack.

[0078] In some embodiments of the disclosed technology, the battery cells forming the battery module may be pouch-type battery cells.

[0079] During the charging and discharging of the battery cell, the battery cell undergoes volume changes through the insertion and deintercalation of electrode materials. When the volume of the battery cell expands significantly, the pouch-shaped casing may be damaged, and even when gas ejection or explosion occurs, it may cause direct damage to adjacent battery cells.

[0080] Based on some embodiments of the disclosed technology, a thermally insulating adhesive composition is injected into the housing of a battery module and contacts one or more battery cells in the battery module, thereby securing the battery cells within the module housing. Specifically, the thermally insulating adhesive composition may be disposed between: the battery cells and the side panels of the housing; between the lower panel of the housing and the battery cells; and / or between the upper panel of the housing and the battery cells. The thermally insulating resin layer formed on a portion or the entire surface between the battery cells and the panels, after curing, can prevent battery cell flow due to impact and vibration, and can prevent damage to the battery cells, both externally and internally, due to external impact and vibration. It can also effectively dissipate heat generated during the charging and discharging of the battery cells to prevent the problems described above.

[0081] Furthermore, battery packs implemented based on some embodiments of the disclosed technology may include two or more battery modules. The battery modules in the battery pack may be electrically connected. In some embodiments, a thermally insulating adhesive composition may be disposed inside the battery pack to secure the modules and effectively transfer heat.

[0082] This battery pack can be used in devices that use secondary batteries as a power source for all purposes. As specific examples, battery packs implemented based on some embodiments of the disclosed technology can be used in electric vehicles or hybrid vehicles, but the disclosed technology is not limited thereto.

[0083] In the following text, some embodiments of the disclosed technology will be described in detail by way of example only. The following examples and experimental results illustrate some embodiments of the disclosed technology described in this patent document in more detail, and the disclosed technology should not be construed as being limited thereto.

[0084] (Methods for evaluating physical properties)

[0085] 1. Measurement of elastic modulus and elongation

[0086] Evaluation was performed according to ASTM D638-14, and Type 4 samples with a thickness of 3 mm were fabricated. The tensile speed was 5 mm / min, and the samples were stretched at a constant speed until the fracture point, with the force and strain measured recorded. The modulus of elasticity was calculated using the strain and stress at points from 0.5% to 3.0%, and the elongation was recorded as the value at the fracture point of the sample.

[0087] 2. Hardness Measurement

[0088] Evaluation was performed according to ASTM D2240, and flat samples were fabricated with a width of 25 mm, a length of 25 mm, and a thickness of 5 mm or greater. Hardness was measured using a hardness measuring instrument with Shore A units, and the hardness was evaluated by the value that stabilized after pressing the sample surface for 20 seconds. Five points on the sample were measured, and their average value was recorded.

[0089] 3. Measurement of adhesive shear strength

[0090] A flat plate with a width of 25 mm and a length of 100 mm was fabricated using an aluminum shell with an insulating film. A heat-dissipating resin layer with a thickness of 0.3 mm, a width of 25 mm, and a length of 25 mm was coated onto the flat plate. Two flat plates were placed together to create a sample for evaluation. The sample was cured for 72 hours and then fastened to a tensile testing machine. It was stretched at a constant speed of 12.7 mm / min to the breaking point, and the maximum force measured was recorded.

[0091] 4. Measurement of thermal conductivity

[0092] The evaluation was conducted according to ISO 22007-2, and a flat sample with a width of 50 mm, a length of 50 mm, and a thickness of 5 mm was fabricated. A hot plate sensor was placed between the two samples and stabilized at a reference temperature of 25°C, and then the thermal conductivity was measured.

[0093] [Example 1]

[0094] An aliphatic polyester polyol as the main agent and an alicyclic isocyanate as the curing agent were mixed at an equivalent ratio of 1:1.05 and a volume ratio of 1:1 to prepare a two-component urethane adhesive composition. Alumina and aluminum hydroxide solids (alumina:alumina weight ratio = 2:8) were mixed at 220 parts by weight based on 100 parts by weight of resin. After curing at 25°C for 72 hours, a resin composition exhibiting an elastic modulus of 20 MPa, an adhesive strength of 3.0 MPa, and a viscosity of approximately 450,000 cP at room temperature was prepared. This composition was then coated onto a battery module as a heat-dissipating resin layer. Polycaprolactone polyol was used as the aliphatic polyester polyol, and isophorone diisocyanate (IPDI) was used as the alicyclic isocyanate.

[0095] [Example 2]

[0096] Except that poly(1,4-butanediol adipic acid) as an aliphatic polyester polyol is used as the main agent, hexamethylene-1,6-diisocyanate (HDI) as an aliphatic isocyanate is used as the curing agent, and an elastic modulus of 1 MPa and an adhesive strength of 0.5 MPa are exhibited, a resin composition with a viscosity of about 250,000 cP at room temperature is prepared in the same manner as in Example 1, and it is coated onto the battery module as a heat dissipation resin layer.

[0097] [Example 3]

[0098] Except that poly(1,4-butanediol adipic acid), an aliphatic polyester polyol, is used as the main agent and exhibits an elastic modulus of 10 MPa and an adhesive strength of 2 MPa, a resin composition with a viscosity of approximately 200,000 cP at room temperature is prepared in the same manner as in Example 1 and is coated onto the battery module as a heat-dissipating resin layer.

[0099] [Example 4]

[0100] A two-component silicone adhesive composition was prepared by mixing divinylmethyl-terminated polydimethylsiloxane as the main agent and dimethylsiloxane-methylhydrosiloxane copolymer as the curing agent in a 1:1 equivalent ratio. A resin composition exhibiting an elastic modulus of 5 MPa, an adhesive strength of 1.5 MPa, and a viscosity of approximately 130,000 cP at room temperature was prepared after curing at 25°C for 72 hours. This resin composition was then coated onto a battery module as a heat-dissipating resin layer.

[0101] [Example 5]

[0102] In addition to having a solid content of 300 parts by weight of mixed alumina and aluminum hydroxide (alumina:alumina weight ratio = 5:5) based on 100 parts by weight of resin and exhibiting an elastic modulus of 2 MPa and an adhesive strength of 0.7 MPa, a resin composition having a viscosity of about 300,000 cP at room temperature was prepared in the same manner as in Example 4, and this resin composition was coated onto the battery module as a heat-dissipating resin layer.

[0103] [Comparative Example 1]

[0104] A two-component urethane adhesive composition was prepared by mixing polycarbonate polyol as the main agent and aromatic isocyanate as the curing agent at an equivalent ratio of 1:1.05 and a volume ratio of 1:1. Alumina and aluminum hydroxide solids (alumina:alumina weight ratio = 2:8) were mixed at 220 parts by weight based on 100 parts by weight of resin. After curing at 25°C for 72 hours, a resin composition exhibiting an elastic modulus of 100 MPa, an adhesive strength of 4.0 MPa, and a viscosity of approximately 500,000 cP at room temperature was prepared. This resin composition was coated onto the battery module as a heat-dissipating resin layer. 4,4'-Diphenylmethane diisocyanate (MDI) was used as the aromatic isocyanate.

[0105] [Comparative Example 2]

[0106] Except that isophorone diisocyanate (IPDI), an alicyclic isocyanate, was used as a curing agent and exhibited an elastic modulus of 50 MPa and an adhesive strength of 3.0 MPa, a resin composition having a viscosity of about 250,000 cP at room temperature was prepared in the same manner as in Comparative Example 1, and this resin composition was coated onto the battery module as a heat-dissipating resin layer.

[0107] [Comparative Example 3]

[0108] A resin composition with a viscosity of approximately 300,000 cP at room temperature was prepared in the same manner as in Example 1, except that polypropylene glycol, as an aliphatic polyether polyol, was used as the main agent, hexamethylene-1,6-diisocyanate (HDI), as an aliphatic isocyanate, was used as the curing agent, and exhibited an elastic modulus of 0.5 MPa and an adhesive strength of 0.1 MPa. This resin composition was coated onto the battery module as a heat-dissipating resin layer.

[0109] [Comparative Example 4]

[0110] A resin composition having a viscosity of about 450,000 cP at room temperature was prepared in the same manner as in Example 4, except that it was prepared based on 100 parts by weight of resin with a mixed alumina and aluminum hydroxide solid content of 400 parts by weight (alumina:alumina weight ratio = 2:8) and exhibiting an elastic modulus of 0.5 MPa and an adhesive strength of 0.1 MPa. This resin composition was coated onto the battery module as a heat-dissipating resin layer.

[0111] (Battery module manufacturing)

[0112] The resin composition prepared according to Examples 1 to 5 and Comparative Examples 1 to 4 is introduced between the lower plate and the battery cell in an aluminum module housing in which pouch-type battery cells are stacked and stored, and coated between the battery cell and the housing, thereby creating a heat-dissipating resin layer formed therein in the battery module.

[0113] [Experimental Example 1] Evaluation of the Battery Module

[0114] 1. Evaluation of battery structural performance

[0115] The battery module was fastened to an impact testing machine, and impact loads were then applied to the module in each axial direction. Subsequently, the battery module was fastened to a vibration testing machine to apply vibration loads. After evaluating the vibration and impact, it was determined whether the module's exterior was damaged, whether the heat-dissipating resin layer was cracked or broken, or whether the module voltage was abnormal. The results are shown in Table 1 below.

[0116] <Structural Performance Evaluation Criteria>

[0117] ○: The module has no external damage, no cracks or breaks in the heat dissipation resin layer, and no abnormal voltage inside the module.

[0118] ×: One of the following occurs: external damage to the module, cracks and breaks in the heat dissipation resin layer, and abnormal voltage in the module.

[0119] 2. Battery reliability assessment

[0120] In a constant temperature and humidity chamber at 30 to 35°C, fully charged battery modules are connected to a charger / discharger and subjected to cyclic testing with constant charging and discharging currents. Charge and discharge cycles are performed up to 800 to 1200 times, with insulation breakdown and remaining capacity measured every 100 cycles. After completing the charge and discharge tests, it is determined whether the battery module's insulation is broken, whether the electrolyte solution in the battery cells is leaking, whether the battery cell exterior is damaged, and whether the battery cell's internal structure is damaged.

[0121] 5. Evaluation criteria depending on the reliability of the cycle.

[0122] ○: The battery module has no insulation breakdown, the battery cell electrolyte solution has no leakage, the battery cell exterior is undamaged, and the battery cell interior is undamaged.

[0123] ×: One or more of the following occur: insulation breakdown of the battery module, leakage of electrolyte solution in the battery cell, damage to the exterior of the battery cell, and damage to the interior of the battery cell.

[0124]

[0125] The disclosed technology can be implemented in the above-disclosed embodiments to provide a battery assembly including a low-hardness heat-dissipating resin layer, which exhibits the ability to prevent damage due to the high speed of the battery.

[0126] The specific physical properties that cause damage to the outer surface of the battery cell due to expansion during charging and discharging.

[0127] Furthermore, the disclosed technology can be implemented in some embodiments to minimize the risk of insulation breakdown of the battery assembly or leakage of the electrolyte solution of the battery cell, thereby extending the life of the battery assembly.

[0128] Furthermore, the disclosed technology can be implemented in some embodiments to provide a battery assembly including a low-hardness heat-dissipating resin layer, thereby suppressing battery cell flow that may occur due to vibration and external impact in a particular automotive driving environment, and thus preventing damage from occurring both outside and inside the battery cell.

[0129] The disclosed technologies can be implemented in rechargeable secondary batteries and battery modules widely used in battery-powered devices or systems, including, for example, digital cameras, mobile phones, laptops, hybrid vehicles, electric vehicles, uninterruptible power supplies, battery storage power stations, and battery power storage devices, including those for solar panels, wind turbines, and other green technology generators. Specifically, the disclosed technologies can be implemented in various energy sources and power sources, thereby mitigating climate change associated with energy and power use. Secondary batteries or battery modules based on the disclosed technologies can be used to address various adverse effects, such as air pollution and greenhouse gas emissions, by powering electric vehicles (EVs) as an alternative to vehicles using fossil fuel-based engines and by providing battery-based energy storage systems (ESS) to store renewable energy sources such as solar and wind power.

[0130] Only specific examples of implementation methods for certain embodiments are described. Variations, improvements, and enhancements may be made to the disclosed embodiments and other embodiments based on the disclosure of this patent document.

Claims

1. A battery assembly, the battery assembly comprising: A battery casing, the battery casing comprising at least one casing plate; A battery cell assembly, the battery cell assembly being located in the battery housing and structured to include a plurality of battery cells electrically connected to each other and disposed in the battery housing; as well as A heat-dissipating resin layer is placed between the at least one outer casing plate and the battery cell assembly. The heat-dissipating resin layer has an adhesive shear strength of at least 0.2 MPa as measured according to ASTM D1002, and satisfies the following formula: [Formula 1] Wherein, A is the softness index of the heat-dissipating resin layer, E is the elastic modulus of type 4 according to ASTM D638-14 at a tensile speed of 5 mm / min, and L is the elongation of type 4 according to ASTM D638-14 at a tensile speed of 5 mm / min.

2. The battery assembly according to claim 1, wherein, The heat-dissipating resin layer has an elastic modulus of 1 to 20 MPa as measured according to ASTM D638-14.

3. The battery assembly according to claim 1, wherein, The elongation of the heat-dissipating resin layer is in the range of 30% to 450% as measured according to ASTM D638-14.

4. The battery assembly according to claim 1, wherein, The adhesive shear strength of the heat-dissipating resin layer is in the range of 0.2 to 5.0 MPa as measured according to ASTM D1002.

5. The battery assembly according to claim 1, wherein, The heat-dissipating resin layer has a Shore A hardness value of 40 to 75 as measured according to ASTM D2240.

6. The battery assembly according to claim 1, wherein, The heat-dissipating resin layer comprises at least one selected from the group consisting of urethane resins, epoxy resins, silicone resins, acrylic resins, olefin resins, and ethylene-vinyl acetate resins.

7. The battery assembly according to claim 1, wherein, The heat-dissipating resin layer has a thermal conductivity of 1 to 3 W / mk.

8. The battery assembly according to claim 7, wherein, The heat dissipation resin layer includes at least one thermally conductive filler selected from at least one of the group consisting of alumina, aluminum hydroxide, silicon nitride, zinc oxide, magnesium oxide, boron nitride, aluminum nitride, and silicon carbide.

9. The battery assembly according to claim 1, wherein, The value of A in Equation 1 is 2.1 or less.

10. The battery assembly according to claim 1, wherein, The battery casing includes at least one of an upper casing plate, a lower casing plate, a side casing plate, and an end casing plate.

11. The battery assembly according to claim 1, wherein, The battery unit is a pouch-type battery unit.

12. The battery assembly according to claim 1, wherein, The battery assembly is a battery module or battery pack.

13. A battery pack, the battery pack comprising: A battery casing, the battery casing comprising at least one casing plate; as well as A plurality of battery modules are disposed within the battery housing. Each battery module includes: a battery cell assembly comprising a plurality of battery cells electrically connected to each other and disposed within the battery housing; and a heat-dissipating resin layer disposed between the at least one housing plate and the battery cell assembly to dissipate heat from the battery cell assembly. The heat-dissipating resin layer has an adhesive shear strength of at least 0.2 MPa as measured according to ASTM D1002, and satisfies the following formula: [Formula 1] Wherein, A is the softness index of the heat-dissipating resin layer, E is the elastic modulus of type 4 according to ASTM D638-14 at a tensile speed of 5 mm / min, and L is the elongation of type 4 according to ASTM D638-14 at a tensile speed of 5 mm / min.

14. The battery pack according to claim 13, wherein, The heat-dissipating resin layer has an elastic modulus of 1 to 20 MPa as measured according to ASTM D638-14; or the elongation of the heat-dissipating resin layer is in the range of 30% to 450% as measured according to ASTM D638-14; or the adhesive shear strength of the heat-dissipating resin layer is in the range of 0.2 to 5.0 MPa as measured according to ASTM D1002; or the heat-dissipating resin layer has a Shore A hardness value of 40 to 75 as measured according to ASTM D2240.

15. The battery pack according to claim 13 or 14, wherein, The heat-dissipating resin layer comprises at least one selected from the group consisting of urethane resin, epoxy resin, silicone resin, acrylic resin, olefin resin and ethylene-vinyl acetate resin; or wherein the heat-dissipating resin layer has a thermal conductivity of 1 to 3 W / mk; or wherein the value of A in Formula 1 is 2.1 or less.

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