Battery module and manufacturing method thereof

Abstract

Embodiments provide a battery module and a manufacturing method thereof, the battery module comprising: a cell stack in which a plurality of battery cells are stacked, the cell stack comprising an electrode accommodation portion, in which an electrode assembly is accommodated, and a terrace portion, formed by sealing an exterior material at the edge of at least one side of the electrode accommodation portion; a bus bar assembly including a bus bar electrically connected to the battery cells and disposed on at least one side of the cell stack; and a protective member facing the terrace portion of the battery cells, wherein at least a portion of the protective member is formed of a polymer foam.

Description

Battery module and manufacturing method thereof

[0001] The present invention relates to a battery module and a method for manufacturing the same.

[0002] Secondary batteries (battery cells), unlike primary batteries, offer the convenience of rechargeability, attracting considerable attention as a power source for various mobile devices and electric vehicles. A battery cell can consist of an electrode assembly, including a positive electrode plate, a negative electrode plate, a separator, and an outer packaging material that encloses and seals the electrode assembly. A battery module connects multiple such battery cells to form a large-capacity energy storage device.

[0003] Meanwhile, battery cells may catch fire under various events, such as swelling in the battery cells, overcharging in the battery cells, exposure to heat in the battery cells, or external impact in the battery cells.

[0004] There is a concern that flames or high-temperature gases emitted from a battery cell where an event has occurred may cause a chain reaction of fires in neighboring battery cells contained within the battery device, resulting in a thermal runaway situation.

[0005] To prevent this, in a battery device including a plurality of battery cells, a structure is required in which the sealing of the outer material of the battery cell is not easily broken even when the internal pressure of the battery cell increases.

[0006] The present invention has been devised to solve at least some of the problems of the prior art as described above, and aims to provide a battery module capable of stably maintaining the sealing of a battery cell.

[0007] In addition, it is an object of the present invention to provide a battery module including a protective member having a shape corresponding to the space between a plurality of battery cells so as to effectively maintain sealing of the battery cells.

[0008] In order to achieve the above purpose, in embodiments, a battery module is provided, including a cell stack in which a plurality of battery cells are stacked, including an electrode receiving portion in which an electrode assembly is received, a terrace portion formed by sealing an outer material at at least one edge of the electrode receiving portion, a bus bar assembly including a bus bar electrically connected to the battery cell and disposed on at least one side of the cell stack, and a protective member facing the terrace portion of the battery cell, wherein at least a portion of the protective member is formed of a polymer foam.

[0009] In embodiments, the polymer foam may include at least one of a polyurethane resin and a phenol resin.

[0010] In embodiments, the polyurethane resin may include 110 to 300 parts by weight of isocyanate per 100 parts by weight of polyol.

[0011] In embodiments, the weight average molecular weight of the polyol may be from 100 to 10,000.

[0012] In embodiments, the number of hydroxyl groups of the polyol may be 1.5 to 6.0.

[0013] In embodiments, the content of hydroxyl groups in the polyol may be 1 to 15 wt%.

[0014] In embodiments, the terrace portion is arranged to surround at least a portion of a lead tab extending from at least one side of the electrode receiving portion, and the protective member can be brought into contact with the terrace portion.

[0015] In embodiments, an adhesive member may be placed between the protective member and the terrace member.

[0016] In embodiments, the protective member may be in contact with at least one of the electrode receptacle and the busbar assembly.

[0017] In embodiments, the protective member may be formed by foaming and curing a liquid polymer material filled in the space between the busbar assembly and the electrode receptacle.

[0018] In embodiments, the edge of the protective member facing the electrode receptacle may have a chamfered shape.

[0019] In embodiments, a method for manufacturing a battery module is provided, including a cell stacking step of stacking a plurality of battery cells to form a cell stack; a busbar connecting step of interconnecting the cell stack and the busbar assembly; and a protection member arranging step of arranging a protection member between the plurality of battery cells, wherein the protection member includes a polymer foam formed by foaming and curing a liquid polymer material.

[0020] In the embodiments, the polymer foam comprises at least one of a polyurethane resin and a phenol resin, wherein the polyurethane resin may comprise 110 to 300 parts by weight of isocyanate per 100 parts by weight of polyol.

[0021] In embodiments, the protective member placement step may include a filling step of filling a liquid polymer material into a space formed between the cell laminate and the busbar assembly; and a synthesis step of foaming and curing the liquid polymer material filled into the space.

[0022] In embodiments, the protective member placement step may include a processing step of foaming and curing a liquid polymer material to fabricate the protective member; and an insertion step of inserting the protective member between the cell laminate and the busbar assembly.

[0023] In embodiments, the method further comprises a catalytic step of adding a catalyst that induces a reaction between a polyol and an isocyanate, wherein the catalyst may be at least one selected from the group consisting of pentamethyldiethylene triamine, dimethyl cyclohexyl amine, bis-(2-dimethyl aminoethyl)ether, triethylene diamine potassium octoate, tris(dimethylaminomethyl)phenol, and potassium acetate.

[0024] According to embodiments, a battery module capable of stably maintaining the sealing of a battery cell can be implemented.

[0025] Additionally, according to embodiments, a battery module including a protective member having a shape corresponding to a space between a plurality of battery cells can be provided.

[0026] Figure 1 is a perspective view of a battery module.

[0027] Figure 2 is an exploded perspective view of the battery module.

[0028] Figure 3 is a perspective view of a battery cell.

[0029] Fig. 4 is an exemplary cross-sectional view according to part II' of Fig. 1.

[0030] Figure 5 is a reference drawing showing a protective member arranged between a cell laminate and a busbar assembly.

[0031] Fig. 6 is an exemplary cross-sectional view according to part II-II' of Fig. 5.

[0032] Figure 7 is a reference diagram for explaining the manufacturing process of a battery module.

[0033] Figure 8 is a reference drawing for explaining the combination of a protective member and a cell laminate according to another embodiment.

[0034] Fig. 9 is an exemplary cross-sectional view according to part III-III' of Fig. 8.

[0035] Before going into the detailed description of the present invention, it should be noted that the terms and words used in this specification and claims should not be interpreted as limited to their usual or dictionary meanings, but should be interpreted with meanings and concepts that conform to the technical idea of ​​the present invention based on the principle that the inventor can appropriately define the concept of the term in order to explain his own invention in the best way. Therefore, the embodiments described in this specification and the configurations illustrated in the drawings are only the most preferred embodiments of the present invention and do not represent all of the technical idea of ​​the present invention. Therefore, it should be understood that there may be various equivalents and modified examples that can replace them at the time of this application.

[0036] The same reference numbers or symbols used in each drawing attached to this specification represent parts or components that perform substantially the same functions. For convenience of explanation and understanding, the same reference numbers or symbols may be used in different embodiments. In other words, even if components with the same reference numbers are depicted in multiple drawings, they do not necessarily represent a single embodiment.

[0037] In the following description, singular expressions include plural expressions unless the context clearly indicates otherwise. Terms such as "comprises" or "comprises" should be understood to indicate the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification, but do not preclude the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0038] In addition, in the description below, expressions such as top, upper, lower, lower, side, front, and rear are expressed based on the direction shown in the drawing, and it is noted in advance that they may be expressed differently if the direction of the object in question changes.

[0039] Additionally, terms including ordinal numbers, such as "first," "second," etc., may be used in this specification and claims to distinguish between components. These ordinal numbers are used to distinguish identical or similar components from each other, and the use of these ordinal numbers should not be interpreted in a limited manner. For example, components associated with these ordinals should not be interpreted in a restricted manner, such as in the order of use or arrangement, based on their numbers. If necessary, each ordinal number may be used interchangeably.

[0040] Hereinafter, embodiments of the present invention will be described with reference to the attached drawings. However, the spirit of the present invention is not limited to the presented embodiments. For example, those skilled in the art who understand the spirit of the present invention may propose other embodiments within the spirit of the present invention by adding, modifying, or deleting components, etc., but such embodiments will also be considered to be within the spirit of the present invention. The shapes and sizes of elements in the drawings may be exaggerated for clarity.

[0041]

[0042] Figure 1 is a perspective view of a battery module (10).

[0043] Figure 2 is an exploded perspective view of a battery module (10).

[0044] Figure 3 is a perspective view of a battery cell (100).

[0045] Fig. 4 is an exemplary cross-sectional view according to part II' of Fig. 1.

[0046] In embodiments, the battery module (10) may include a cell stack (CS) in which a plurality of battery cells (100) are stacked, a busbar assembly (200) electrically connected to the cell stack (CS), and a housing (400) in which the cell stack (CS) is accommodated.

[0047] A plurality of battery cells (100) may be stacked in one direction to form at least a portion of a cell stack (CS). For example, as illustrated in FIG. 2, a plurality of battery cells (100) may be stacked in a direction horizontal to the lower cover of the housing (400) (e.g., in the Y-axis direction). Hereinafter, the stacking direction of the battery cells (100) is referred to as a "first direction."

[0048] The battery cell (100) included in the cell stack (CS) may be configured to convert chemical energy into electrical energy to supply power to an external circuit, or to receive power from the outside, convert electrical energy into chemical energy, and store electricity. For example, the battery cell (100) may be configured as a nickel metal hydride (Ni-MH) battery or a lithium ion (Li-ion) battery capable of being charged and discharged, but is not limited thereto.

[0049] In embodiments, the battery cell (100) may be a pouch-type secondary battery having a structure in which an electrode assembly is housed inside a flexible pouch. For example, referring to FIG. 3, the electrode assembly (110) and the electrolyte (not shown) in the battery cell (100) may be housed inside a pouch formed by bonding one or more outer materials (120). However, the battery cell (100) included in the battery module (10) is not limited to a pouch-type secondary battery. For example, the battery cell may be configured as a can-type secondary battery in which an electrode assembly is housed inside a square case having a predetermined rigidity. Alternatively, the battery cell may have a configuration in which a plurality of pouch-type secondary batteries are grouped together to form a bundle.

[0050] In embodiments, the battery cell (100) may include an electrode receiving portion (121) in which an electrode assembly (110) and an electrolyte (not shown) are received, a metallic lead tab (130) electrically connected to the electrode assembly (110) and exposed to the outside of the outer covering (120), and a sealing portion (122, 123) formed by bonding the outer covering (120) to at least one edge of the electrode receiving portion (121).

[0051] The electrode assembly (110) may have a form in which a plurality of positive and negative electrode plates are laminated with a separator therebetween. The battery cell (100) may have a plurality of lead tabs (130), one of which may be electrically connected to the positive plate, and the other of which may be electrically connected to the negative plate. The lead tabs (130) may be exposed to the outside of the outer material (120). The lead tabs (130) may be electrically connected to the busbars (210) of the busbar assembly (200).

[0052] The electrode receiving portion (121) can be formed by forming one or more outer materials (120). For example, after forming one or two receiving portions on one outer material (120), the electrode receiving portion (121) can be formed by folding the outer material (120) so that the receiving portions form one space.

[0053] The outer material (120) may be formed of a material capable of protecting the electrode assembly (110) from the external environment, and may be composed of, for example, a flexible aluminum laminated film.

[0054] The sealing portion (122, 123) may be formed by bonding the outer material (120) along at least a portion of the perimeter of the electrode receiving portion (121). The bonding method of the outer material (120) may be a thermal bonding method, but is not limited thereto.

[0055] The sealing portion (122, 123) may include a first sealing portion (122) formed in a portion where the lead tab (130) is placed, and a second sealing portion (123) formed in a portion where the lead tab (130) is not placed.

[0056] Here, the area from the edge of the electrode receiving portion (121) to the end of the first sealing portion (122) is defined as the terrace portion (CT) of the battery cell (100). For example, when the lead tab (130) of the battery cell (100) extends in the second direction (X-axis direction), the terrace portion (CT) may be a portion corresponding to the area from the edge of the electrode receiving portion (121) in the second direction (X-axis direction) to the end of the outer material (120) in the second direction (X-axis direction). Accordingly, the terrace portion (CT) may surround at least a portion of the lead tab (130) extending from the electrode receiving portion (121).

[0057] In order to increase the joint reliability of the sealing portions (122, 123) and to minimize the area of ​​the sealing portions (122, 123), at least some of the sealing portions (122, 123) may have a shape in which they are folded at least once. For example, as shown in FIG. 3, the second sealing portion (123) may have a shape in which the exterior material (120) is bent at least once.

[0058] In the battery cell (100), if a single sheet of outer material (120) is folded in half and has a structure that surrounds the electrode assembly (110), there is no need to form a sealing portion (122, 123) in the folded portion of the outer material (120). In this case, as illustrated in FIG. 3, the sealing portions (122, 123) may be formed only on three of the four edges of the electrode receiving portion (121), and a folding portion (124) may be formed on the remaining one side.

[0059] However, the pouch structure of the battery cell (100) is not limited to the above-described structure. For example, unlike that illustrated in FIG. 3, it is also possible for two outer layers to be overlapped with an electrode assembly in between to form an electrode receiving portion, and for a sealing portion to be formed on four sides along the perimeter of the electrode receiving portion.

[0060] If a thermal runaway phenomenon occurs in the battery cell (100), there is a risk that the electrode receiving portion (121) may swell or burst, causing high-temperature gas or flames to be ejected outside the battery cell (100). If such high-temperature gas or flames indiscriminately spread inside or outside the battery module (10), there is a risk that they may cause a chain reaction of fires in the densely packed battery cells (100) and an explosion of the battery module (10).

[0061] In particular, the first sealing portion (122), which is the portion that surrounds the lead tab (130), is difficult to have a folded shape more than once like the second sealing portion (123) due to the lead tab (130), and therefore, compared to the second sealing portion (123), there may be a higher risk of the seal being broken due to the pressure of the gas rising inside the electrode receiving portion (121). In this case, there is a risk that the gas may be ejected toward the lead tab (130) through which a high-voltage current flows, causing ignition.

[0062] To prevent this, the battery module (10) according to the embodiments may further include a protective member (500) that can prevent the sealing of the sealing portion (122, 123) of the battery cell (100) from being broken.

[0063] The protective member (500) may be configured such that at least a portion thereof is in contact with the terrace portion (TR) of the battery cell (100). For example, when the terrace portion (TR) is formed at both ends of the battery cell (100) in the longitudinal direction (e.g., in the X-axis direction), the protective member (500) may be configured such that it is in contact with the terrace portion (TR) at both ends of the battery cell (100) in the longitudinal direction (e.g., in the X-axis direction). The protective member (500) prevents deformation or seal release of the terrace portion (TR) due to pressure generated inside the battery cell (100) by contacting the terrace portion (TR) where the lead tab (130) is exposed to the outside, thereby stably maintaining the sealing of the sealing portions (122, 123).

[0064] Referring to FIGS. 2 and 4, in the battery module (10), a plurality of protective members (500) may be arranged. The plurality of protective members (500) may be arranged between the terrace portions (TR) of adjacent battery cells (100). That is, in one battery cell (100), one side and the other side of the terrace portion (TR) may each be in contact with the protective member (500). Accordingly, the protective member (500) may apply surface pressure to the terrace portion (TR), thereby preventing the seal of the terrace portion (TR) from being released due to the internal pressure of the battery cell (100).

[0065] A plurality of battery cells (100) of a cell stack (CS) can be electrically connected to each other through a busbar assembly (200).

[0066] The busbar assembly (200) may be positioned to face at least one side of the cell stack (CS). For example, referring to FIG. 2, the busbar assembly (200) may be positioned to face the cell stack (CS) in a direction (e.g., Y-axis direction) perpendicular to the first direction (X-axis direction).

[0067] The busbar assembly (200) includes a conductive busbar (210) and is arranged on at least one side of the cell stack (CS) to electrically connect the battery cells (100) to each other.

[0068] The bus bar (210) may be formed of a conductive material (e.g., metal) and serves to electrically connect a plurality of battery cells (100) to each other. The bus bar (210) may be electrically connected to the battery cells (100) while being coupled to the bus bar frame (220). A slit hole (211) configured to allow a lead tab (130) of the battery cell (100) to be inserted may be formed in the bus bar (210). A terminal portion (212) that may be electrically connected to an external circuit of the battery module (10) may be arranged on at least a portion of the bus bars (210).

[0069] An end cover (300) may be placed on the outer surface of the busbar assembly (200) in the battery module (10). The end cover (300) may include a material having rigidity (e.g., a metal such as aluminum or a resin compound) to protect the cell stack (CS) and the busbar assembly (200) from external impact.

[0070] Meanwhile, in order to prevent the end cover (300) and the busbar assembly (200) from being electrically short-circuited, an insulating cover (not shown) including an insulating material may be placed between the end cover (300) and the busbar assembly (200).

[0071] The cell stack (CS) can be accommodated inside a housing (400) that forms the exterior of the battery module (10). The housing (400) is placed outside the cell stack (CS) (110) to protect the battery cells (100) from the external environment.

[0072] As an example, the housing (400) may include a housing body (410) having a cross-sectional shape with one side open, and a housing cover (420) that is combined with the housing body (410) to form an internal space.

[0073] Additionally, the housing (400) may have a structure in which end covers (300) are coupled to the longitudinal front and rear sides of the housing (400) to cover the internal space formed by the housing body (410) and the housing cover (420).

[0074] Meanwhile, at least one surface of the housing (400) may function as a heat dissipation plate that dissipates heat generated from the battery cell (100) to the outside. To increase heat dissipation efficiency, a heat dissipation member may be placed between the housing (400) and the cell stack (CS). The heat dissipation member may include a thermally conductive material to enable heat generated from the cell stack (CS) to be more smoothly transferred to the housing (400), thereby preventing overheating of the cell stack (CS). For example, the heat dissipation member may include at least one of a thermally conductive resin or a thermally conductive adhesive.

[0075]

[0076] In embodiments, the protective member (500) may be formed at least in part by polymer foam. For example, a liquid resin raw material, which is a raw material of the protective member (500), may be filled into the space between the cell laminate (CS) and the busbar assembly (200), and then foamed and cured to form a protective member (500) having a polymer foam structure. Hereinafter, such a protective member (500) will be described in detail with reference to FIGS. 5 to 7.

[0077] Fig. 5 is a reference drawing showing a protective member (500) arranged between a cell stack (CS) and a busbar assembly (200).

[0078] Fig. 6 is an exemplary cross-sectional view according to part II-II' of Fig. 5.

[0079] Figure 7 is a reference drawing for explaining the manufacturing process of a battery module (10).

[0080] The protective member (500) and the battery module (10) including the same described in FIGS. 5 to 7 include all the technical features of the protective member (500) and the battery module (10) including the same described in FIGS. 1 to 4, and therefore, redundant descriptions may be omitted.

[0081] In embodiments, the battery module (10) may include a protective member (500) filled in the space between the cell stack (CS) and the busbar assembly (200). For example, a liquid resin, which is a raw material for the protective member (500), may be injected into the space between the cell stack (CS) and the busbar assembly (200), and then the protective member (500) may be formed through a foaming / curing process.

[0082] The protective member (500) may be arranged between the terrace portions (TR) of neighboring battery cells (100). Referring to FIGS. 5 and 6, the protective member (500) may be configured to be filled between the terrace portions (TR) of neighboring battery cells (100) and to apply surface pressure to the terrace portions (TR) of the battery cells (100). Accordingly, the protective member (500) and the terrace portions (TR) of the battery cells (100) may be arranged alternately in the first direction (Y-axis direction), which is the cell stacking direction, inside the busbar assembly (200).

[0083] The protective member (500) can be formed by a foaming process after a liquid polymer material is filled between the busbar frame (220) and the cell laminate (CS).

[0084] The liquid polymer material forming the protective member (500) may include a polyurethane material or a phenol resin.

[0085] For example, the material forming the protective member (500) may include polyisocyanurate resin (PIR) having heat stability and flame retardancy among polyurethane materials.

[0086] Polyisocyanurate resin has a closed cell ratio of 93% or higher, making it relatively light, and its internal bubbles have a closed cell structure, providing excellent insulation performance and preventing temperature transfer between lead tabs (130) of adjacent battery cells (100). In addition, its compressive strength is excellent at 1.5 kgf / cm2 to 10 kgf / cm2, which is advantageous in providing pressure to suppress venting of the lead tab (130) of the battery cell (100). In addition, it is stable within the operating temperature range of the battery cell (100) as there is almost no change in dimension or physical properties at a heat-resistant temperature of 250 degrees and a cold-resistant temperature of -50 degrees.

[0087]

[0088] Below, the material forming the protective member (500) (hereinafter referred to as “protective material”) is described in detail.

[0089] The protective material may include a polyurethane resin containing 110 to 250 parts by weight of isocyanate per 100 parts by weight of polyol.

[0090] Here, the polyol may be an ether-based or ester-based polyol.

[0091] The polyol may be one or a mixture of two or more selected from among polyether polyols, polyester polyols, polytetramethylene ether glycol polyols, polyharnstoff dispersion polyols, amine-modified polyols, Mannich polyols, and mixtures thereof.

[0092] The molecular weight (g / mol) of the polyol is preferably 100 to 10,000, and more preferably 500 to 5,000. In the following description, it is noted that 'molecular weight' means weight-average molecular weight (Mw).

[0093]

[0094] Example 1 Example 2 Comparative Example 1 Comparative Example 2 Molecular weight of polyol (g / mol) 1000 3000 350 11000 Temperature at which weight loss begins in TGA analysis ( )250250185220

[0095]

[0096] Referring to Table 1 above, when the molecular weight of the polyol is 350 (Comparative Example 1) and 11000 (Comparative Example 2), the temperature at which weight loss begins in thermogravimetric analysis (TGA) decreases compared to when the molecular weight is 1000 (Example 1) and 3000 (Example 2).

[0097] In the protective member (500) formed in the form of PIR foam, if the molecular weight of the polyol is too small, the polymer chains inside the foam become shorter, thus increasing defects in the synthesized foam, and thus the polymer chains tend to decompose easily at high temperatures, which may reduce the thermal stability of the PIR foam. In general, the higher the molecular weight of the polyol, the better the thermal stability of the PIR foam. However, if the molecular weight of the polyol is too large, the polymer chains tend to stick to each other, and as a result, the viscosity of the polyol increases, so that the uniformity of stirring when stirring the polyol and isocyanate is reduced, resulting in insufficient reaction and a tendency to reduce the thermal stability.

[0098] For example, when the molecular weight of the polyol is less than 500, the thermal stability of the polyurethane resin synthesized by the formation of monool is reduced, and there is a disadvantage in that it easily melts in the event of a fire, and when the molecular weight of the polyol exceeds 5000, the amorphous carbon chain within the polyol structure increases, and the thermal stability of the polyurethane resin is also reduced.

[0099] In addition, the number of hydroxyl groups of the polyol may be 1.5 to 6.0, and more specifically, the number of hydroxyl groups may be 2.0 to 4.0. It is effective that the content of hydroxyl groups present in the polyol is 1 to 15 wt%. This is to obtain stable adhesive force and dimensional stability by manufacturing a polyurethane resin containing an optimal content of a polyol with an optimal molecular weight. If the number of hydroxyl groups and the content of hydroxyl groups exceed the above range, when the polyurethane resin is synthesized, there may be problems with dimensional stability, such as insufficient adhesive force with the polymer and metal materials of the cell, busbar, and upper plate, or excessive shrinkage and expansion of the synthesized polyurethane resin.

[0100] Here, the molecular weight of the polyol may be 100 to 10,000, and the hydroxy content present in the polyol may be 1 to 15 wt% of the total polyol.

[0101] The isocyanate that reacts with polyol is not particularly limited to the common ones used in the production of polyurethane resin, but specifically, hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), 4,4'-dicyclohexylmethane diisocyanate (H12MDI), polyethylene polyphenyl isocyanate, toluene diisocyanate (TDI), 2,2'-diphenylmethane diisocyanate (2,2'-MDI), 2,4'-diphenylmethane diisocyanate (2,4'-MDI), 4,4'-diphenylmethane diisocyanate (4,4'-MDI, monomeric MDI), polymeric diphenylmethane diisocyanate (polymeric MDI), orthotoluidine diisocyanate (TODI), naphthalene diisocyanate (NDI), xylene diisocyanate (XDI), It may preferably include one or a mixture of two or more selected from lysine diisocyanate (LDI) and triphenylmethane triisocyanate (TPTI), or it may include 4,4'-diphenylmethane diisocyanate (4,4'-MDI, monomeric MDI), polymeric diphenylmethane diisocyanate (polymeric MDI) or polyethylene polyphenyl isocyanate.

[0102] The mixing ratio of the polyol and isocyanate may be configured so that the isocyanate has 110 to 300 parts by weight per 100 parts by weight of the polyol.

[0103]

[0104] Example 1 Comparative Example 1 Comparative Example 2 Isocyanate weight parts (polyol = 1) 1.6 1.0 3.5 Weight loss start temperature in TGA analysis ( )250200280Nitrogen content7.66.49.6Compressive strength(kgf / cm2)5.23.81.4Foam density(kg / m3)62.769.847.8Venting time (cycle)19001420940

[0105]

[0106] In a battery module (10) in which a protective member (500) formed of polyisocyanurate resin (PIR) was not placed, venting occurred at approximately 600 cycles.

[0107] Referring to Table 2 above, when the isocyanate content is less than 110 parts by weight (Comparative Example 1), it was confirmed that the thermal stability was inferior to that of Example 1 based on the TGA analysis data, and it was observed that the foam melted after the 600 degree sintering test. On the other hand, when the isocyanate content was 110 parts by weight or more and 300 parts by weight or less (Example 1), the thermal stability improved, and it was confirmed that the foam specimen did not melt after the 600 degree sintering test. In addition, it was confirmed that the compressive strength was excellent when the isocyanate content was 110 to 300 parts by weight (Example 1), and the compressive strength decreased when it was out of the range. This is because the hardness of the foam is low when it is less than 110, resulting in ductility, and because the density is low when it is 300 or more.

[0108] When the content of isocyanate is less than 110 parts by weight, the formation of isocyanurate bonds that increase thermal stability is not sufficient, so there is a problem of the resin melting in the event of a high temperature such as a fire. When the content of isocyanate exceeds 300 parts by weight, isocyanurate bonds are excessively formed, so the elemental ratio of oxygen in the polyurethane resin produced increases, which may cause a problem of increased heat generation in the event of a fire.

[0109] Meanwhile, foam density affects vehicle weight, so it's important to maintain a relatively low density while still ensuring compressive strength and thermal stability. Considering thermal stability, compressive strength, and density, an isocyanate content of 110 to 300 parts by weight per 100 parts by weight of polyol is considered optimal.

[0110] Since the nitrogen content of the final foam in the above range differs due to the NCO group contained in the isocyanate, the range of the present invention (110 to 300) can be specified through analysis of the nitrogen content contained in the foam.

[0111] Additionally, it is known that when the nitrogen content is high, a large amount of nitrogen oxide, a toxic gas, is generated during combustion, so an isocyanate content exceeding 300 is not desirable as it increases the amount of toxic gas generated during a fire.

[0112] The mixing ratio of the above polyol and isocyanate may vary depending on the content of additives such as catalysts, foaming agents, blowing agents, and flame retardants, and is therefore not limited to the above range.

[0113] In embodiments, the polyurethane resin included in the protective member (500) may additionally include a foaming agent, a flame retardant, a catalyst, or a foaming agent.

[0114] For example, a catalyst may be added to induce a reaction between polyol and isocyanate in order to manufacture a polyurethane resin included in the protective member (500). The catalyst may be one or more selected from pentamethyldiethylene triamine, dimethyl cyclohexyl amine, bis-(2-dimethyl aminoethyl) ether, triethylene diamine, potassium octoate, tris(dimethylaminomethyl)phenol, potassium acetate, or a mixture thereof, and the content of the catalyst may be added in an amount of 0.1 to 5 parts by weight relative to the polyol. Alternatively, the content of the catalyst may be added in an amount of 0.5 to 3 parts by weight relative to the polyol.

[0115] When the catalyst content is less than 0.1 parts by weight, the reaction between polyol and isocyanate proceeds too slowly, causing a problem in which the resin synthesis speed is slowed down. When the catalyst content exceeds 5 parts by weight, the resin synthesis reaction proceeds too quickly, causing the polyurethane resin to react without the contents being sufficiently mixed, resulting in an uneven composition and solidification that is too rapid, making it difficult to proceed with subsequent processes.

[0116] In addition, in the embodiments, a foaming agent may be included to control the density of the polyurethane resin that is the protective material, and a foaming agent may be additionally included to ensure the uniformity of the foam cells of the polyurethane resin and improve the stability of the resin foam.

[0117] Additionally, flame retardants such as TCPP (Tris(2-ChloroPropyl) Phosphate), TCEP (Tris(2-Chroroethyl) Phosphate), TEP (triethyl phosphate), and TMP (Trimethyl phosphate) can be additionally added to improve the thermal stability of the polyurethane resin.

[0118] Since isocyanate contains a large amount of NCO groups, as the addition ratio of isocyanate increases, the nitrogen and oxygen contents also increase. The nitrogen content can range from 3 to 9 wt% of the total polyurethane resin. If the nitrogen content exceeds 9 wt%, there is a problem of excessive nitrogen oxide generation in the event of a fire, and if the nitrogen content is less than 3 wt%, the amount of isocyanurate bonds is insufficient, which reduces the thermal stability of the polyurethane resin and causes the resin to melt in the event of a fire, which may be undesirable.

[0119] In addition, the hydrogen content may be 2 to 8 wt% of the total polyurethane resin. In addition, the oxygen content may be 10 to 25 wt% of the total polyurethane resin. If the hydrogen and oxygen contents are less than the above ranges, the isocyanurate structure content may be excessive, and the amount of nitrogen oxides generated may be excessively large due to the thermal decomposition of the polyurethane resin in the event of a fire, which may cause the problem of toxic gas generation. If the hydrogen and oxygen contents exceed the above ranges, the chemical reaction for generating isocyanurate in the polyurethane resin may not be sufficient, resulting in poor dimensional stability and melting of the polyurethane resin in the event of a fire.

[0120] Accordingly, the density of the polyurethane resin manufactured as a protective material can be 52 kg / m3, and the thermal conductivity of the polyurethane resin can be 0.018 Kcal / mh. It could be.

[0121] In addition, the polyurethane resin has excellent insulation performance and can be used at low temperatures (-40 ) can also be expected to have an internal insulation effect in the battery cell (100), and has the advantage of being able to block heat from spreading between adjacent battery cells (100).

[0122]

[0123] Below, a method for manufacturing a battery module (10) including a protective member (500) formed of the above-described protective material is described.

[0124] A method for manufacturing a battery module (10) may include a cell stacking step of stacking a plurality of battery cells (100) to form a cell stack (CS), and a busbar connecting step of interconnecting the cell stack (CS) and a busbar assembly (200).

[0125] Referring to the upper left of Fig. 7, a plurality of battery cells (100) can be stacked on each other to form a cell stack (CS). A busbar assembly (200) is arranged on one side of the cell stack (CS), and the plurality of battery cells (100) can be electrically connected to each other through the busbar assembly (200).

[0126] Referring to the upper right of FIG. 7, the cell stack (CS) and the busbar assembly (200) can be accommodated in the housing body (410). For example, the housing body (410) having a cross-sectional shape with one side open can be assembled to surround at least a portion of the cell stack (CS).

[0127] A method for manufacturing a battery module (10) may include a protective member arrangement step of arranging a protective member (500) between a plurality of battery cells (100). Here, the protective member (500) may include a polymer foam formed by foaming and curing the liquid polymer material described above.

[0128] Additionally, the protective member placement step may include a filling step of filling the liquid polymer material into a space formed between the cell laminate (CS) and the busbar assembly (200), and a synthesis step of foaming and curing the liquid polymer material filled into the space.

[0129] Referring to the lower right of Fig. 7, when the cell stack (CS) is accommodated in the housing (400) body, it can be turned over so that the space between the cell stack (CS) and the busbar assembly (200) is exposed upward. A nozzle (20) can approach this exposed space to inject a liquid polymer material, which becomes the material of the protective member (500), between the cell stack (CS) and the busbar assembly (200). After being injected, the liquid polymer material foams and fills the space between the cell stack (CS) and the busbar assembly (200).

[0130] Meanwhile, the method for manufacturing a battery module (10) may further include a catalyst step of adding a catalyst that induces a reaction between a polyol and an isocyanate. Here, the catalyst may be at least one selected from the group consisting of pentamethyldiethylene triamine, dimethyl cyclohexyl amine, bis-(2-dimethyl aminoethyl) ether, triethylene diamine, potassium octoate, tris(dimethylaminomethyl)phenol, and potassium acetate, as described above. The catalyst may be added in an amount of 0.1 to 5 parts by weight based on the weight of the polyol.

[0131] Referring to the lower left of FIG. 7, the casing can be finished by assembling the end cover (300) and the housing cover (420) while the liquid polymer material is foamed and hardened to form the protective member (500).

[0132] The protective member (500) according to the embodiments can be filled to fit the shape of the space in which the protective member (500) is placed during the foaming process of the raw material. For example, referring to FIG. 6, as the raw material of the protective member (500) is foamed, the space formed between the busbar frame (220) and the terrace portion (TR) and electrode receiving portion of the battery cell (100) is filled, so that the protective member (500) can be formed to fit the shape of the space. Accordingly, the protective member (500) can be in contact with all of the busbar assembly (200), the terrace portion (TR) and the electrode receiving portion (121) of the battery cell (100).

[0133] In this way, the protective member (500) is configured to fill the space between the busbar assembly (200) and the cell stack (CS) during the forming process, so that surface pressure can be applied over a wide area of ​​the terrace portion (TR) of the battery cell (100), and the sealing of the terrace portion (TR) can be more effectively prevented from being released due to the internal pressure of the battery cell (100).

[0134] In addition, since the protective member (500) is formed by the foaming process in this way, it is possible to manufacture a protective member (500) that can apply an appropriate surface pressure even if the space formed between the busbar assembly (200) and the cell laminate (CS) is narrow or has a complex shape.

[0135]

[0136] Meanwhile, in other embodiments, the protective member may be manufactured using a mold provided separately from the battery module (10) and then inserted into the space between the cell stack (CS) and the busbar assembly (200). Hereinafter, a battery module (10) including a protective member according to other embodiments will be described with reference to FIGS. 8 and 9.

[0137] FIG. 8 is a reference diagram for explaining the combination of a protective member (610) and a cell stack (CS) according to another embodiment.

[0138] Fig. 9 is an exemplary cross-sectional view according to part III-III' of Fig. 8.

[0139] In the battery module (10) described in FIGS. 8 and 9, other configurations (e.g., battery cell (100), cell stack (CS), busbar assembly (200)) other than the configuration of the protective member (610) are all the same as the configuration of the battery module (10) described in FIGS. 1 to 7, and therefore, for detailed descriptions thereof, reference may be made to FIGS. 1 to 7.

[0140] In the battery module (10), the protective member (610) can be manufactured in a shape corresponding to the space between the cell stack (CS) and the bus bar assembly (200), and then inserted and placed between the cell stack (CS) and the bus bar assembly (200).

[0141] For example, 100 g of polyol containing approximately 7 wt% of hydroxyl groups and 130 g of 4,4'-MDI are stirred at 4000 rpm for 10 seconds to produce a polymer material (polyurethane mix), and the polymer material is poured into a mold having a release agent applied to the surface, and the temperature outside the mold is set to 60 degrees Celsius, and left for 15 minutes so that the mix solution foams and hardens inside the mold, thereby producing a polyurethane resin having a mold-shaped hexahedron. However, the specific manufacturing method of the protective member (610) is not limited to that described above.

[0142] The protective member (610) can be manufactured by cutting the manufactured polyurethane resin to a size corresponding to the space between the cell laminate (CS) and the busbar assembly (200).

[0143] At this time, in order to ensure that the protective member (610) and the terrace portion (TR) of the battery cell (100) are in close contact with each other, the protective member (610) may be formed to have a width equal to or greater than the gap between the terrace portions (TR) of the neighboring battery cells (100). Accordingly, the protective member (610) may be forcibly fitted between the terrace portions (TR) of the two neighboring battery cells (100).

[0144] The manufactured protective member (610) can be inserted between the terrace portions (TR) of the battery cell (100).

[0145] In the insertion direction of the protective member (610), the protective member (610) can be inserted from the opposite side of the side where the second sealing portion (123) having a shape in which the outer material (120) is bent at least once is disposed in the battery cell (100). For example, as illustrated in FIG. 8, when the second sealing portion (125) is formed on the upper portion of the battery cell (100), the protective member (610) can be moved upward from the lower portion of the battery cell (100) to be disposed between the terrace portions (TR) of the battery cell (100), or the cell stack (CS) can be moved downward so that the protective member (610) is positioned between the terrace portions (TR) of the battery cell (100).

[0146] In order to prevent damage to the battery cell (100) during the process of inserting the protective member (610) between the terrace portions (TR), at least a portion of the edge of the protective member (610) may be formed to have a curvature. For example, referring to FIG. 9, a chamfered portion (610a) having a predetermined curvature may be formed on the edge of the protective member (610). Accordingly, it is possible to prevent the electrode receiving portion of the battery cell (100) from being damaged during the process of inserting and connecting the protective member (610) to the cell stack (CS).

[0147] Meanwhile, an adhesive member (620) may be placed between the protective member (610) and the battery cell (100) so that the protective member (610) can be stably fixed between the cell stack (CS) and the housing (400). For example, referring to FIG. 9, an adhesive member (620) may be applied between the terrace portion (TR) of the battery cell (100) and the protective member (610), so that the protective member (610) can be adhered to the terrace portion (TR), and thus the protective member (610) can be stably fixed between the battery cells (100).

[0148]

[0149] Below, a method for manufacturing a battery module (10) including a protective member (610) as described in FIGS. 8 and 9 is described.

[0150] A method for manufacturing a battery module (10) may include a cell stacking step of stacking a plurality of battery cells (100) to form a cell stack (CS), and a busbar connecting step of interconnecting the cell stack (CS) and a busbar assembly (200).

[0151] As described with reference to the upper left of Fig. 7, a plurality of battery cells (100) may be stacked on each other to form a cell stack (CS). A busbar assembly (200) is arranged on one side of the cell stack (CS), and the plurality of battery cells (100) may be electrically connected to each other through the busbar assembly (200).

[0152] Additionally, as described with reference to the upper right of FIG. 7, the cell stack (CS) and the busbar assembly (200) may be accommodated in a housing (400). For example, a housing (400) body having a cross-sectional shape with one side open may be assembled to surround at least a portion of the cell stack (CS).

[0153] A method for manufacturing a battery module (10) may include a protective member arrangement step of arranging a protective member (610) between a plurality of battery cells (100). Here, the protective member (610) may include a polymer foam formed by foaming and curing the liquid polymer material described above.

[0154] The protective member placement step may include a processing step of foaming and curing a liquid polymer material in a mold to produce a protective member (610) and an insertion step of inserting the protective member (610) produced in the processing step into a space between the cell laminate (CS) and the busbar assembly (200).

[0155]

[0156] In embodiments, the protective member (500, 610) pressurizes the terrace portion (TR) of the battery cell (100) so that the sealing of the outer material can be maintained even in a situation where the internal pressure of the battery cell (100) increases due to thermal runaway of the battery cell (100).

[0157] In addition, since the protective member (500) is formed through a process of filling and foaming a liquid polymer material into the space between the cell laminate (CS) and the busbar assembly (200), it can be provided in a shape corresponding to the space between the cell laminate (CS) and the busbar assembly (200). Accordingly, the contact area between the protective member (500) and the terrace portion (TR) can be further increased, and the protective member (500) can more effectively apply surface pressure to the terrace portion (TR).

[0158] Alternatively, the protective member (610) may be pre-formed in a shape corresponding to the space between the cell laminate (CS) and the busbar assembly (200) and then inserted and placed between the cell laminate (CS) and the busbar assembly (200), thereby effectively applying surface pressure to the terrace portion (TR) to maintain a sealed state.

[0159] In addition, the protective member (500, 610) formed of such polymer foam has excellent insulation performance, so that an insulation effect can also be expected between components of the battery module (10) (e.g., between two adjacent terrace portions (TR), or between two adjacent lead tabs).

[0160]

[0161] While various embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and it will be apparent to those skilled in the art that various modifications and variations are possible without departing from the technical spirit of the present invention as set forth in the claims. Furthermore, the embodiments described above may be implemented by deleting some components, and the embodiments may be implemented in combination with each other.

Claims

1. A battery cell stack including a plurality of stacked battery cells, including an electrode receiving portion in which an electrode assembly is received, and a terrace portion formed by sealing an outer material at at least one edge of the electrode receiving portion; A busbar assembly comprising a busbar electrically connected to the battery cell and disposed on at least one side of the cell stack; and Includes a protective member facing the terrace portion of the battery cell, The above protective member is a battery module formed at least in part from polymer foam.

2. In paragraph 1, A battery module wherein the polymer foam comprises at least one of a polyurethane resin and a phenol resin.

3. In paragraph 2, A battery module in which the polyurethane resin contains 110 to 300 parts by weight of isocyanate per 100 parts by weight of polyol.

4. In paragraph 3, A battery module wherein the weight average molecular weight of the above polyol is 100 to 10,000.

5. In paragraph 3, A battery module wherein the number of hydroxyl groups of the above polyol is 1.5 to 6.

0.

6. In paragraph 5, A battery module wherein the content of the hydroxyl group of the polyol is 1 to 15 wt%.

7. In paragraph 1, The above terrace portion is arranged to surround at least a portion of a lead tab extending from at least one side of the electrode receiving portion, The above protective member is a battery module that comes into contact with the terrace portion.

8. In paragraph 7, A battery module in which an adhesive member is placed between the protective member and the terrace portion.

9. In paragraph 7, A battery module in which the protective member is in contact with at least one of the electrode receiving portion and the busbar assembly.

10. In paragraph 1, The above protective member is a battery module formed by foaming and curing a liquid polymer material filled in a space between the busbar assembly and the electrode receiving portion.

11. In paragraph 1, A battery module having a corner facing the electrode receiving portion of the above protective member having a chamfered shape.

12. A cell stacking step of forming a cell stack by stacking multiple battery cells; A busbar connection step for interconnecting the above cell laminate and busbar assembly; and A protective member arrangement step for arranging a protective member between the plurality of battery cells is included. A method for manufacturing a battery module, wherein the above protective member comprises a polymer foam formed by foaming and curing a liquid polymer material.

13. In paragraph 12, The polymer foam comprises at least one of a polyurethane resin and a phenol resin, A method for manufacturing a battery module, wherein the polyurethane resin contains 110 to 300 parts by weight of isocyanate per 100 parts by weight of polyol.

14. In paragraph 12, The above protective member placement step is A filling step of filling the liquid polymer material into the space formed between the cell laminate and the busbar assembly; and A method for manufacturing a battery module, comprising a synthesis step in which the liquid polymer material filled in the above-mentioned space is foamed and cured.

15. In paragraph 12, The above protective member placement step is A processing step of manufacturing the protective member by foaming and curing the liquid polymer material; and A method for manufacturing a battery module, comprising an insertion step of inserting the protective member between the cell stack and the busbar assembly.

16. In paragraph 14 or 15, It further includes a catalytic step of adding a catalyst that induces a reaction between polyol and isocyanate, A method for manufacturing a battery module, wherein the catalyst is at least one selected from the group consisting of pentamethyldiethylene triamine, dimethyl cyclohexyl amine, bis-(2-dimethyl aminoethyl)ether, triethylene diamine, potassium octoate, tris(dimethylaminomethyl)phenol, and potassium acetate.

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