Battery module, battery pack and vehicle including same

Abstract

The present invention relates to a battery module comprising: a cell stack including multiple battery cells; a module case configured to accommodate the cell stack; and a heat conductive layer provided between the module case and the cell stack and configured to have a difference in adhesive force from the outside to the inside thereof.

Description

Battery modules, battery packs containing the same, and vehicles

[0001] The present invention relates to a battery module, a battery pack including the same, and a vehicle.

[0002] This application claims priority to Korean Patent Application No. 10-2023-0162568, filed on November 21, 2023, and all contents disclosed in the specification and drawings of the said application are incorporated herein by reference.

[0003] Secondary batteries, which boast high electrical properties such as high energy density and easy applicability across a wide range of product categories, are widely used not only in portable devices but also in electric vehicles (EVs) and hybrid electric vehicles (HEVs) powered by electrical power sources. These batteries are attracting attention as a new energy source for environmental friendliness and energy efficiency, not only because they can dramatically reduce fossil fuel use, but also because they produce no byproducts from energy use.

[0004] Commonly used secondary battery types today include lithium-ion batteries, lithium polymer batteries, nickel-cadmium batteries, nickel-metal hydride batteries, and nickel-zinc batteries. When high output voltage is required, multiple battery cells are connected in series to form a battery module or battery pack. Furthermore, to increase charge / discharge capacity, multiple battery cells are connected in parallel to form a battery module or battery pack.

[0005] When connecting multiple battery cells in series or parallel to form a battery pack, it's common to first construct a battery module containing at least one battery cell, and then use this at least one battery module to add other components to form a battery pack or battery rack. Recently, battery packs in the cell-to-pack form, where multiple battery cells are housed directly in a pack housing or other device, without modularization, have also been manufactured.

[0006] Meanwhile, in conventional battery modules, a thermally conductive adhesive may be applied to one side of the stacked cell structure to cool the battery cells. In such conventional battery modules, swelling of the battery cells during charge / discharge cycles can lead to various problems.

[0007] For example, when swelling occurs in a battery cell, the entire battery cell of the cell stack moves toward the outermost edge, while one side of the cell stack that is in direct contact with the thermally conductive adhesive remains fixed by the cured thermally conductive adhesive. This can lead to damage in the portion of the cell case with relatively low elongation.

[0008] Alternatively, when swelling of the battery cells occurs, the cured thermally conductive adhesive may be damaged by movement of the cell stack, resulting in partial or complete structural collapse of the cell stack or battery device. Furthermore, during this process, the battery cells may detach from the thermally conductive adhesive, which may degrade the heat dissipation performance of the battery cells.

[0009] Accordingly, the present invention has been created to solve the above problems, and its purpose is to provide a battery module having an improved structure so that stability can be secured even when a swelling phenomenon occurs, and a battery pack and a vehicle including the same.

[0010] However, the problems to be solved by the present invention are not limited to the problems described above, and other problems not mentioned can be clearly understood by those skilled in the art from the description of the invention described below.

[0011] To solve the above problem, a battery module according to one embodiment of the present invention includes: a cell stack including a plurality of battery cells; a module case configured to accommodate the cell stack; and a thermally conductive layer provided between the module case and the cell stack and configured to have a difference in adhesive strength from the outside to the inside.

[0012] The above heat-conducting layer may be configured so that the adhesive strength becomes weaker from the outside to the inside.

[0013] The above thermal conductive layer may include a first thermal conductive layer configured to be in contact with the module case, and a second thermal conductive layer provided on the inner side of the first thermal conductive layer and configured to be in contact with the cell stack.

[0014] The first heat-conducting layer and the second heat-conducting layer may be configured to have different adhesive strengths.

[0015] The adhesive strength of the second heat-conducting layer may be configured to be weaker than the adhesive strength of the first heat-conducting layer.

[0016] The second heat-conducting layer may be formed of a material having a lower hardening degree than the first heat-conducting layer.

[0017] The second heat-conducting layer may be formed of a material including silicon.

[0018] The second thermally conductive layer may be configured to surround the terminal portion of the battery cell.

[0019] The second thermally conductive layer may be configured to be inserted between the plurality of battery cells when swelling of the battery cells occurs.

[0020] The first thermally conductive layer may be configured to be in contact with an end portion of the battery cell.

[0021] The first thermally conductive layer may be configured to surround the end of the battery cell.

[0022] The above thermally conductive layer may be configured to include a portion in which the thickness of the second thermally conductive layer differs as it goes toward the outermost direction of the stacking direction of the battery cell.

[0023] In addition, the present invention provides a battery pack characterized by including a battery module according to the present invention.

[0024] And, the present invention provides an automobile characterized by including a battery module according to the present invention.

[0025] According to one embodiment of the present invention, stability against swelling of a battery device including a battery cell, i.e., a battery module or a battery pack, can be secured.

[0026] In particular, according to one embodiment of the present invention, in a battery module or battery pack comprising a plurality of battery cells in a stacked form, the cell stacking state can be stably maintained under normal conditions. In addition, damage to battery module components, such as battery cells, can be prevented when swelling occurs.

[0027] In addition, according to one embodiment of the present invention, in a swelling occurrence situation, collapse of the structure of the battery device due to breakage of the curable adhesive can be prevented or suppressed.

[0028] Furthermore, according to one embodiment of the present invention, the problem of battery cells detaching from the thermally conductive adhesive due to swelling, thereby reducing heat dissipation, can be prevented. Accordingly, the cooling performance of the battery device can be consistently maintained.

[0029] Accordingly, according to these aspects of the present invention, the cycle performance of a battery device can be improved. In other words, according to various aspects of the present invention, a battery device with an improved lifespan that can be stably used for a long period of time can be provided.

[0030] In addition, the present invention may have various other effects, which will be described in each embodiment configuration, or an explanation of effects that can be easily inferred by a person skilled in the art will be omitted.

[0031] The following drawings attached to this specification illustrate preferred embodiments of the present invention, and together with the detailed description of the invention described below, serve to further understand the technical idea of ​​the present invention, and therefore, the present invention should not be interpreted as being limited to matters described in such drawings.

[0032] FIG. 1 is a perspective view of a battery module according to one embodiment of the present invention.

[0033] Figure 2 is an exploded perspective view of a battery module according to one embodiment of the present invention.

[0034] Fig. 3 is a cross-sectional view of a battery module according to one embodiment of the present invention. For example, Fig. 3 may be a drawing illustrating cross-section I-I' of Fig. 1.

[0035] FIG. 4 is a cross-sectional view of a battery module according to one embodiment of the present invention when a battery cell is swollen.

[0036] Figure 5 is a cross-sectional view of a battery module according to another embodiment of the present invention.

[0037] FIG. 6 is a drawing showing an example of a thermal conductive layer included in a battery module according to another embodiment of the present invention.

[0038] Figure 7 is an enlarged view of part A of Figure 5.

[0039] FIG. 8 is an enlarged view of part A of FIG. 5 when a battery cell is swollen in a battery module according to another embodiment of the present invention.

[0040] Figure 9 is an enlarged cross-sectional view of a battery module according to another embodiment of the present invention.

[0041] FIG. 10 is an enlarged cross-sectional view of a battery module according to another embodiment of the present invention.

[0042] FIG. 11 is a cross-sectional view of a battery module according to another embodiment of the present invention.

[0043] Figure 12 is an enlarged view of part B of Figure 11.

[0044] FIG. 13 is a cross-sectional view of a battery module according to another embodiment of the present invention.

[0045] FIG. 14 is a cross-sectional view of a battery module according to another embodiment of the present invention.

[0046] FIG. 15 is a perspective view schematically showing the configuration of a battery pack according to one embodiment of the present invention.

[0047] Figure 16 is a schematic perspective view of a vehicle according to one embodiment of the present invention.

[0048] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. Prior to this, it should be noted that the terms and words used in this specification and claims should not be construed as limited to their conventional or dictionary meanings. Based on the principle that the inventor can appropriately define the concepts of terms to best explain his or her invention, they should be interpreted in a way that aligns with the technical spirit of the present invention.

[0049] Accordingly, the embodiments described in this specification and the configurations illustrated in the drawings are merely the most preferred embodiments of the present invention and do not represent all of the technical ideas 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 filing this application.

[0050] Furthermore, the present invention includes various embodiments. For each embodiment, redundant descriptions of substantially identical or similar components will be omitted, and the differences will be described.

[0051] Meanwhile, in the present invention, terms indicating directions such as up, down, left, right, front, and back may be used, but it is obvious to those skilled in the art that these terms are only for convenience of explanation and may vary depending on the location of the target object or the location of the observer.

[0052] For example, in an embodiment of the present invention, the X-axis direction shown in the drawing may mean the left-right direction, the Y-axis direction may mean the front-back direction perpendicular to the X-axis direction on a horizontal plane (XY plane), that is, the length direction of the battery cell, and the Z-axis direction may mean the up-down direction (vertical direction) perpendicular to both the X-axis direction and the Y-axis direction, that is, the height direction of the battery cell.

[0053]

[0054] FIG. 1 is a perspective view of a battery module according to an embodiment of the present invention, FIG. 2 is an exploded perspective view of a battery module according to an embodiment of the present invention, and FIG. 3 is a cross-sectional view of a battery module according to an embodiment of the present invention. In addition, FIG. 4 is a cross-sectional view of a battery module according to an embodiment of the present invention when a battery cell is swollen. For example, FIGS. 3 and 4 may be drawings illustrating a cross-section taken along line I-I' of FIG. 1.

[0055] Referring to FIGS. 1 to 4, a battery module (10) according to the present invention includes a cell stack (100), a module case (200), and a thermal conductive layer (300).

[0056] The cell stack (100) may include one or more battery cells (110), particularly a plurality of battery cells (110). Here, each battery cell (110) may refer to a single secondary battery or may refer to a battery group comprising multiple secondary batteries. In this specification, the description will be based on the assumption that a battery cell (110) represents a single secondary battery.

[0057] A plurality of battery cells (100) may include an electrode assembly, a cell case that accommodates the electrode assembly, and electrode leads (111) that are connected to the electrode assembly and extend outward from the cell case to function as electrode terminals. At this time, the shape of the battery case may be configured in various ways, and depending on the shape of the battery case, the battery cells (110) may be classified into pouch-type cells, cylindrical cells, square cells, etc. Since the types of these battery cells (110) were widely known at the time of filing of the present invention, a detailed description thereof will be omitted. The present invention is applicable to all types of secondary batteries known at the time of filing of the present invention, and is not limited to a specific type of secondary battery.

[0058] In the cell stack (100), a plurality of battery cells (110) may be configured in a form in which they are stacked in at least one direction. For example, as illustrated in FIG. 2, a plurality of battery cells (110) may be stacked in a form in which they are arranged in a horizontal direction, particularly in the left-right direction (X-axis direction). In addition, a plurality of battery cells (110) provided in the cell stack (100) may be electrically connected to each other in series and / or in parallel through a bus bar (not illustrated) or the like.

[0059] Although not shown in the drawing, the cell stack (100) may further include a barrier in addition to the battery cells (110). One or more barriers, particularly a plurality of barriers, may be provided in one cell stack (100). Furthermore, the barriers may be arranged between adjacent battery cells (110) in the cell stack (100), or at the outermost edge of the cell stack (100) in the stacking direction. The barriers may be configured in a plate shape and may face the surface of the battery cells (110), particularly the outer surface of the storage portion of the pouch-shaped cells.

[0060] Meanwhile, referring to FIG. 2, the module case (200) may be configured to accommodate a cell stack (100). Specifically, a receiving space may be formed in the module case (200), and the cell stack (100) may be configured to be accommodated in the receiving space.

[0061] For example, the module case (200) may have a case body (210), a top plate (220), and an end plate (230) to define a receiving space. Then, the cell stack (100) may be positioned in this limited receiving space. The module case (200) may be at least partially composed of metal and / or plastic materials.

[0062] At least some of the various plate-shaped members constituting the module case (200) may be configured in an integrated form. For example, the module case (200), as illustrated in FIG. 2, may include a case body (210) in a U-frame shape in which a lower plate, a left plate, and a right plate are integrated with each other, and a top plate (220) and an end plate (230) may be configured to cover or seal the upper, front, and rear of the case body (210). At this time, various fastening methods such as welding, bonding, bolting, and hooking may be used to couple and fix the top plate (220) and the end plate (230) to the case body (210). Alternatively, the module case (200) may be manufactured in a monoframe form in which the top plate (220) and the case body (210) are integrated with each other. Alternatively, the module case (200) may be manufactured in a form in which each plate is manufactured separately and then coupled and fixed by welding or the like. However, the present invention is not limited to a specific material or shape of the module case (200).

[0063] The above thermal conductive layer (300) may be provided between the cell stack (100) and the module case (200). For example, referring to FIG. 3, the thermal conductive layer (300) may be provided between one side of the cell stack (100), for example, the lower side, and the lower surface of the module case (200).

[0064] And, the thermal conductive layer (300) may be configured to transfer heat between the cell stack (100) and the module case (200). The battery cell (110) may generate heat during use, and if this heat is not properly discharged, the performance of the battery cell (110) cannot be stably guaranteed, and in severe cases, it may lead to thermal runaway, ignition, explosion, etc. of the battery cell. In this respect, the heat generated in the battery cell (110) needs to be properly discharged to the outside through the module case (200). At this time, the thermal conductive layer (300) may ensure that heat transfer between the battery cell (110) and the module case (200) is well performed, thereby stably securing cooling performance for the battery module.

[0065] The thermal conductive layer (300) may include a material capable of transferring heat. In particular, the thermal conductive layer (300) may be made of a resin material, and in this case, the thermal conductive layer (300) may be referred to as a thermal resin. The thermal conductive layer (300) may include various materials, such as urethane, silicone, and epoxy. The thermal conductive layer (300) may be expressed by other terms such as TIM (Thermal Interface Material), potting resin, etc., and as a material of the thermal conductive layer (300) of the battery module (10) according to the present invention, various thermal resins or TIMs known at the time of filing of the present invention may be used.

[0066] Additionally, the thermal conductive layer (300) may be configured to adhere the cell stack (100) to the module case (200). To this end, the thermal conductive layer (300) may include an adhesive component. For example, as illustrated in FIG. 3, when the thermal conductive layer (300) is positioned at the bottom of the cell stack (100), the thermal conductive layer (300) may adhere and fix the lower side of the cell stack (100) to the lower surface of the module case (200).

[0067] The thermal conductive layer (300) may be interposed between all battery cells (110) provided in the cell stack (100) and the module case (200). That is, the thermal conductive layer (300) may be configured to be in direct contact with all battery cells (110) included in the cell stack (100). According to this embodiment of the present invention, heat dissipation through the thermal conductive layer (300) can be achieved for all battery cells (110) included in the battery module (10). Therefore, the overall cooling performance of the battery module (10) can be further improved.

[0068] In particular, in the battery module (10) according to the present invention, the thermal conductive layer (300) may be configured to adhere at least a portion of the cell stack (100) to the module case (200), but to have a difference in adhesive strength. Here, the adhesive strength may mean a force or fixed strength that is fixed between the cell stack (100) and the module case (200) by the thermal conductive layer (300).

[0069] Specifically, the thermal conductive layer (300) may be configured to have a difference in adhesive strength from the outside to the inside. That is, the thermal conductive layer (300) may be configured to have a difference in adhesive strength along a direction perpendicular to one side of the module case (200). The adhesive strength of the thermal conductive layer (300) may gradually vary from the outside to the inside, and may be formed as a multilayer structure in which layers having different adhesive strengths are provided.

[0070] Meanwhile, in this specification, the direction toward the center of the battery module (10) is referred to as the inward direction, and the direction toward the outside of the battery module (10) is referred to as the outward direction. These inward and outward may be concepts indicating relative positions.

[0071] As a more specific example, when the thermal conductive layer (300) is interposed between the lower portion of the cell stack (100) and the lower surface of the module case (200), as in the embodiment of FIG. 3, the adhesive strength of the thermal conductive layer (300) may be configured differently in the vertical direction. In this case, the adhesive strength of the portions of each of the battery cells (110) included in the cell stack (100) that come into contact with the thermal conductive layer (300) may be configured differently in the vertical direction.

[0072] In a cell stack (100) equipped with a plurality of battery cells (110) stacked, when a swelling phenomenon occurs, movement occurs in the stacking direction of the battery cells (110), and one side of the cell stack (100) in contact with the thermal conductive layer (300) is fixed, which may cause damage or breakage of the battery cells (110). However, referring to FIG. 4, in the battery module (10) of the present invention, since the adhesive strength of the thermal conductive layer (300) is configured differently from the outside to the inside, a degree of freedom for movement of the battery cells (110) can be granted up to a certain level. Therefore, the problem of damage to the battery cells (110) when swelling occurs can be suppressed. Accordingly, in the battery module (10) according to the present invention, stability or safety against swelling can be secured.

[0073]

[0074] In particular, the thermal conductive layer (300) may be configured, at least partially, such that the adhesive strength becomes weaker from the outside to the inside. That is, the portion located on the inside of the thermal conductive layer (300) may be configured to have a weaker adhesive strength than the portion located on the outside. For example, in the embodiment illustrated in FIG. 3, the thermal conductive layer (300) may be configured such that the portion located on the upper side has a weaker adhesive strength than the portion located on the lower side.

[0075] Here, weak adhesion can mean that there is adhesion but it is relatively weak compared to other parts, and it can mean that the adhesion is 0, that is, there is no adhesion at all. For example, the inner part of the thermal conductive layer (300) of FIG. 3 can be released from adhesion even with a relatively weak force compared to the outer part of the thermal conductive layer (300). Alternatively, the inner part of the thermal conductive layer (300) may not be able to adhere the battery cells (110) and may only perform the role of transferring heat.

[0076] In the case of a portion where the cell stack (100) and the thermal conductive layer (300) are in direct contact, if the battery cell (110) is secured with a strong adhesive force, the possibility of damage due to swelling may increase. However, in the case of the above-described embodiment, by weakening the adhesive force to the thermal conductive layer (300) at the inner portion of the battery cell (110), the freedom of movement of the battery cell (110) can be granted to a certain level. Therefore, the battery cell (110) can be protected from surrounding stress or impact when swelling occurs. Accordingly, the stability or safety of the battery module (10) against swelling can be further secured.

[0077] Meanwhile, if the adhesive strength of the thermal conductive layer (300) on the inner side of the battery cell (110) is weakened, the adhesive strength with the module case (200) may also be weakened. Therefore, according to the above-described embodiment of the present invention, by strengthening the adhesive strength of the thermal conductive layer (300) on the outer side of the battery cell (110), damage to the battery cell (110) can be prevented when swelling occurs, while the adhesive strength of the outer side of the battery cell (110) with the module case (200) can be maintained. In addition, according to the above-described embodiment of the present invention, the cell stack (100) and the module case (200) can be reliably insulated.

[0078]

[0079] FIG. 5 is a cross-sectional view of a battery module according to another embodiment of the present invention, and FIG. 6 is a drawing showing an example of a thermal conductive layer included in a battery module according to another embodiment of the present invention.

[0080] Referring to FIGS. 5 and 6, the thermal conductive layer (300) may include a first thermal conductive layer (310) and a second thermal conductive layer (320). Here, the first thermal conductive layer (310) and the second thermal conductive layer (320) are unit components of the thermal conductive layer (300) and may be made of different types, i.e., different materials.

[0081] The first thermally conductive layer (310) and the second thermally conductive layer (320) may be arranged in an outer-to-inner direction. Specifically, the first thermally conductive layer (310) may be configured to be in contact with the module case (200). The first thermally conductive layer (310) may indirectly or directly secure the cell stack (100) to the module case (200).

[0082] The second heat-conducting layer (320) may be provided on the inner side of the first heat-conducting layer (310). The second heat-conducting layer (320) may be configured to be in contact with the cell stack (100). Accordingly, the second heat-conducting layer (320) may be interposed between the first heat-conducting layer (310) and the cell stack (100). That is, the module case (200), the first heat-conducting layer (310), the second heat-conducting layer (320), and the cell stack (100) may be stacked in this order from the outer side to the inner side.

[0083] In particular, the thermally conductive layer (300) arranged on one side of the cell stack (100) may be configured in a plate shape. At this time, the heterogeneous unit layers constituting the thermally conductive layer (300), i.e., two or more thermally conductive unit layers, may each be configured in a plate shape and arranged to face each other. For example, referring to the configurations illustrated in FIGS. 5 and 6, one first thermally conductive layer (310) and one second thermally conductive layer (320) may be arranged in a vertically parallel manner in the form of a lying plate.

[0084] The first thermally conductive layer (310) and the second thermally conductive layer (320) may be configured to have different adhesive strengths. In particular, the adhesive strength of the second thermally conductive layer (320) may be configured to be weaker than the adhesive strength of the first thermally conductive layer (310). The second thermally conductive layer (320) may be configured to allow the battery cell (110) to flow when swelling occurs.

[0085] According to this embodiment, the battery module (10) according to the present invention can be provided with a simple structure. Furthermore, according to this embodiment, the battery module (10) according to the present invention can be manufactured more easily. In particular, according to the above embodiment, the problem of battery cells (110) being easily damaged due to swelling can be more effectively prevented.

[0086]

[0087] The thermal conductive layer (300) may be configured to have partially different degrees of hardening. This degree of hardening may refer to the degree of hardening. Under the same conditions, for example, at room temperature, a thermal conductive paste with a high degree of hardening may have higher adhesive strength (holding power) than a thermal conductive paste with a low degree of hardening. Techniques for measuring or determining the degree of hardening are widely known at the time of filing of the present invention, and therefore, a detailed description thereof will be omitted.

[0088] In particular, the thermal conductive layer (300) may be configured to have different degrees of hardening from the outside to the inside. For example, in the exemplary configurations of FIGS. 5 and 6, the first thermal conductive layer (310) and the second thermal conductive layer (320) may be configured to have different degrees of hardening.

[0089] In this configuration, the second thermally conductive layer (320) may be configured to have a lower degree of hardening than the first thermally conductive layer (310). That is, in a normal state after the battery module is manufactured, the first thermally conductive layer (310) is maintained in a relatively harder state than the second thermally conductive layer (320), so that the adhesive force with the module case (200) can be maintained strongly. On the other hand, the second thermally conductive layer (320) may be provided in a form that is not hardened into a solid state, but is maintained in a gel-like state. Accordingly, the second thermally conductive layer (320) may be configured to be maintained in a relatively softer state than the first thermally conductive layer (310), so as to allow movement of the battery cell (110) to a certain extent.

[0090] According to the above-described embodiment of the present invention, by configuring the degree of hardening of the portion of the thermal conductive layer (300) that comes into contact with the inner portion of the battery cell (110) to be low, the battery cell (110) can be sufficiently moved when the cell stack (100) is swollen. Accordingly, damage to the battery cell (110) when swelling can be minimized.

[0091] In particular, the second thermal conductive layer (320) may be formed of a material containing silicon. As a more specific example, the first thermal conductive layer (310) may be formed of a urethane-based thermal resin, and the second thermal conductive layer (320) may be formed of a gel-like silicon-based thermal resin.

[0092] Meanwhile, the fact that the thermal conductive layer (300) has partially different degrees of curing can also be expressed as having partially different properties. Here, the different properties may include a solid state, a gel state, a sol state, etc. as a completely elastic body. That is, the difference in the partial degrees of curing of the thermal conductive layer (300) may appear as a difference in elasticity, viscosity, fluidity, etc. In particular, the thermal conductive layer (300) may have both a solid state portion and a gel state portion. For example, the first thermal conductive layer (310) may have a completely elastic state as a curable resin, and the second thermal conductive layer (320) may have a gel state as an uncured resin.

[0093]

[0094] Fig. 7 is an enlarged view of part A of Fig. 5. Also, Fig. 8 is an enlarged view of part A of Fig. 5 when a battery cell is swollen in a battery module according to another embodiment of the present invention.

[0095] Referring to FIG. 7, the second thermally conductive layer (320) may be configured to surround the end portion of the battery cell (110). That is, the end portion of the battery cell (110) may be configured to be surrounded by the second thermally conductive layer (320). The entire battery cell (110) included in the cell stack (100) may be configured to be inserted into the second thermally conductive layer (320). In the above embodiment, the cell stack (100) may not directly contact the first thermally conductive layer (310). The cell stack (100) may only contact the second thermally conductive layer (320) having a weak adhesive force, and the first thermally conductive layer (310) having a strong adhesive force may be interposed on the outer side of the second thermally conductive layer (320) to fix the second thermally conductive layer (320) to the module case (200). Accordingly, the cell stack (100) can be indirectly fixed to the module case (200) by the first heat-conducting layer (310).

[0096] At this time, the second thermally conductive layer (320) may be interposed between the terminal portions of the battery cell (110). More specifically, the battery cell (110) may include a receiving portion configured to receive the electrode assembly, and a sealing portion configured such that an outer portion of the receiving portion is sealed. The sealing portion is provided to be in contact with the second thermally conductive layer (320), and the second thermally conductive layer (320) may be interposed between the sealing portions of the battery cell (110).

[0097] In particular, as in the embodiment illustrated in FIG. 8, the second thermally conductive layer (320) may be configured to be inserted between a plurality of battery cells (110) when swelling of the battery cells (110) occurs. The second thermally conductive layer (320) may be interposed between the battery cells (110), particularly between the sealing portions, even when swelling of the battery cells (110) does not occur. Furthermore, when the battery cells (110) swell, the gap between the battery cells (110) becomes larger, and a gap may also be formed between the receiving portions. Accordingly, the second thermally conductive layer (320) may be interposed even between the receiving portions of the battery cells (110).

[0098] According to the above-described embodiment of the present invention, the shape of the second thermally conductive layer (320) having weak adhesiveness and fluidity may be deformed depending on whether swelling of the battery cell (110) occurs. In particular, when the second thermally conductive layer (320) is inserted between the battery cells (110), the contact area between the battery cells (110) and the second thermally conductive layer (320) may be further expanded. As a result, the cooling efficiency of the battery cell (110) may be further improved. In addition, the insulation performance between the battery cells (110) may be further improved.

[0099]

[0100] Fig. 9 is an enlarged cross-sectional view of a battery module according to another embodiment of the present invention. Fig. 9 may be an enlarged view of portion A of Fig. 5.

[0101] Unlike the embodiment illustrated in FIG. 8, the first thermally conductive layer (310) may be configured to directly secure the cell stack (100) to the module case (200).

[0102] For example, as in the embodiment illustrated in FIG. 9, the first heat-conducting layer (310) may be configured to be in contact with the end portion of the cell stack (100). That is, the heat-conducting layer (300) may be interposed on one side of the cell stack (100), and the end portion of each battery cell (110) may be configured to be in contact with the boundary surface between the first heat-conducting layer (310) and the second heat-conducting layer (320).

[0103] According to the above-described embodiment of the present invention, since the adhesive force is provided to the cell stack (100) by the first heat-conducting layer (310) when the battery cell (110) swells, the overall structure of the cell stack (100) can be prevented from being significantly disturbed even by shocks such as vibrations. Accordingly, while movement of the cell stack (100) is permitted to a certain extent, the structural rigidity and structural stability of the entire cell stack (100) can be improved.

[0104]

[0105] Fig. 10 is an enlarged cross-sectional view of a battery module according to another embodiment of the present invention. Fig. 10 may be an enlarged view of portion A of Fig. 5.

[0106] Alternatively, as in the embodiment illustrated in FIG. 10, the first thermally conductive layer (310) may be configured to surround the end of the battery cell (110). In other words, the end of the battery cell (110) may be configured to be inserted into the first thermally conductive layer (310). Accordingly, the end of the battery cell (110) may be configured to be surrounded by the first thermally conductive layer (310) as well as the second thermally conductive layer (320). In this case, the contact area between the battery cell (110) and the first thermally conductive layer (310) having strong adhesiveness may increase.

[0107] In the above-described embodiment of the present invention, it can be said that the contact area of ​​the first thermally conductive layer (310) is provided as wide as possible with respect to all battery cells (110) included in the cell stack (100). According to the above-described embodiment of the present invention, since the adhesive force between the cell stack (100) and the module case (200) can be secured, the overall structure of the cell stack (100) can be prevented from being significantly disturbed even by shocks such as vibrations. Accordingly, the structural rigidity and structural stability of the entire cell stack (100) can be secured.

[0108]

[0109] FIG. 11 is a cross-sectional view of a battery module according to another embodiment of the present invention, and FIG. 12 is an enlarged view of part B of FIG. 11.

[0110] Referring to FIGS. 11 and 12, the thermal conductive layer (300) may be configured to have a difference in adhesive strength as it goes toward the outermost direction of the stacking direction of the battery cells (110). That is, the adhesive strength of the thermal conductive layer (300) may be configured to have a difference not only in the direction perpendicular to one side of the module case (200) but also along the direction in which the battery cells (110) are stacked. In particular, the thermal conductive layer (300) may be configured to have a weaker adhesive strength, at least partially, at a portion located at the outer portion in the direction in which a plurality of battery cells (110) are stacked in the cell stack (100), than at a portion located at the center.

[0111] Specifically, the thermally conductive layer (300) may be configured to include a portion having a different thickness from that of the second thermally conductive layer (320). In this case, the thickness of the first thermally conductive layer (310) may also differ depending on the thickness of the second thermally conductive layer (320). The thicknesses of the first thermally conductive layer (310) and the second thermally conductive layer (320) may be constant or may be provided differently.

[0112] As a more specific example, in the embodiment illustrated in FIG. 11, the second heat-conducting layer (320) may be configured so that the portion located at the center of the cell stack (100) is thinner than the portion located at the outer portion of the cell stack (100). Accordingly, the battery cells (110) located at the center of the cell stack (100) can be more strongly adhered, and the battery cells (110) located at the outer portion of the cell stack (100) can move more freely.

[0113] When a plurality of battery cells (110) are stacked in one direction, for example, the left-right direction (X-axis direction), when the battery cells (110) swell, the battery cells (110) located at the outer portion may be pushed more than the battery cells (110) located at the center. Therefore, when the battery cells (110) are fixed with the same adhesive force, the outer cells may be more likely to be damaged due to swelling. However, in the case of the above-described embodiment, by making the adhesive force of the outer cells to the thermal conductive layer (300) weaker than that of the inner cells, freedom of movement of the battery cells (110) may be granted to a certain level. Therefore, when swelling occurs, the problem of damage to the outer cells or collapse of the entire structure of the cell stack (100) may be suppressed.

[0114]

[0115] Referring to FIGS. 11 and 12, the thermally conductive layer (300) may be configured to have a width that gradually changes along the stacking direction of the battery cells (110). In this case, the width of the second thermally conductive layer (320) may be configured to change in the vertical direction at a portion where one battery cell (110) comes into contact with the thermally conductive layer (300). In particular, the first thermally conductive layer (310) may be formed in a convex shape from the left-right end portions to the center portion. That is, the first thermally conductive layer (310) may be configured to have a width that gradually becomes thicker from the front-back end portions to the center portion, such that the center portion is the thickest. The second thermally conductive layer (320) may be formed to have a thick width at the left-right end portions in accordance with the shape of the first thermally conductive layer (310). That is, the second heat-conducting layer (320) may be configured such that the width gradually becomes thinner from the left and right ends to the center, so that the center portion is the thinnest.

[0116] At this time, as illustrated in FIG. 12, at least some of the battery cells (110) may have a boundary line between the first thermally conductive layer (310) and the second thermally conductive layer (320) formed in an oblique or curved shape. In particular, the battery cells (110) included in the cell stack (100) may have a contact area of ​​the second thermally conductive layer (320) with weak adhesiveness that decreases as they go toward the center of the cell stack (100), and a contact area of ​​the first thermally conductive layer (310) with strong adhesiveness that increases. In particular, the battery cells (110) located at the outermost side in the stacking direction of the battery cells (110) are configured to have a large contact area with the second thermally conductive layer (320), thereby ensuring fluidity, and the contact area of ​​the second thermally conductive layer (320) may gradually increase as they go toward the outside.

[0117]

[0118] FIG. 13 is a cross-sectional view of a battery module according to another embodiment of the present invention.

[0119] Referring to FIG. 13, similarly to the embodiment of FIG. 11, the second heat-conducting layer (320) may be formed to have a thick width at the outermost portion in the stacking direction of the battery cells (110), and the first heat-conducting layer (310) may be formed to have a thick width at the central portion in the stacking direction of the battery cells (110). Furthermore, the heat-conducting layer (300) may include a portion in which the boundary line of the second heat-conducting layer (320) and the first heat-conducting layer (310) is formed in a diagonal shape.

[0120] According to this embodiment configuration, at least some of the battery cells (110) included in the cell stack (100) can have their contact areas of the first heat-conducting layer (310) and / or the second heat-conducting layer (320) vertically changed at a constant rate. Accordingly, the fixing force (adhesive force) between a plurality of mutually stacked battery cells (110) can be changed steadily and gradually.

[0121]

[0122] FIG. 14 is a cross-sectional view of a battery module according to another embodiment of the present invention.

[0123] Referring to Fig. 14, the first unit member (310) having strong adhesive force can be brought into contact with all battery cells (110) included in the cell stack (100). However, for at least some battery cells (110), the area in contact with the first unit member (310) can be configured differently.

[0124] For example, in the case of battery cells (110) arranged on the central side in the cell stacking direction, such as in the area indicated by S1, they may only contact the first thermally conductive layer (310) as a whole. On the other hand, in the case of battery cells (110) arranged on the outer side in the cell stacking direction, such as in the area indicated by S3, they may only contact the second thermally conductive layer (320) as a whole. In particular, the outermost cell is included in the S3 area, and this outermost cell does not contact the first thermally conductive layer (310) but only contacts the second thermally conductive layer (320) and may thus have fluidity.

[0125] Additionally, as in the area indicated by S2, the thickness of the second thermally conductive layer (320) may be configured to become thicker as it goes toward the outer portion in the cell stacking direction. Furthermore, in the area indicated by S2, the contact area of ​​the first thermally conductive layer (310) to the battery cell (110) may gradually decrease and the contact area of ​​the second thermally conductive layer (320) may gradually increase as it goes toward the outer portion in the cell stacking direction.

[0126] According to this embodiment of the present invention, since adhesive force is provided to the battery cell (110) arranged at the center of the cell stack (100) by the first heat-conducting layer (310), the overall structure of the cell stack (100) can be prevented from being significantly disturbed even by vibration or swelling. As a result, the structural rigidity and structural stability of the entire cell stack (100) can be improved.

[0127] Moreover, in the above-described embodiment, it can be said that the contact area of ​​the second thermally conductive layer (320) is provided the widest for the outermost cell among all battery cells (110) included in the cell stack (100). Accordingly, since partial movement is allowed during swelling, the possibility of damage to the outermost cell due to swelling can be more reliably reduced.

[0128] In addition, as in the exemplary configurations of FIGS. 11, 13, and 14, when the boundary line between the first thermally conductive layer (310) and / or the second thermally conductive layer (320) is configured in an oblique or curved shape, a configuration in which the adhesive strength of the thermally conductive layer (300) gradually changes along the cell stacking direction can be more easily achieved. In particular, in order to gradually change the adhesive strength of the thermally conductive layer (300) according to the position, it may be a difficult process to sequentially change the composition of the thermally conductive layer (300) according to the position or to diversely arrange several types of thermally conductive materials having different compositions according to the position. However, according to the exemplary configurations described above, a gradual change in the adhesive strength of the thermally conductive layer (300) according to the position of the battery cell (110) can be easily implemented without performing a complicated process.

[0129]

[0130] Meanwhile, although the various drawings of this specification have been described with a focus on a configuration in which the thermal conductive layer (300) is positioned on the lower side of the battery module (10), the thermal conductive layer (300) may be positioned on another side, such as the upper side of the battery module (10). In addition, the thermal conductive layer (300) may be positioned on two or more side surfaces of the battery module (10). For example, the thermal conductive layer (300) may be applied to the upper side and the lower side of the cell stack (100), respectively.

[0131]

[0132] FIG. 15 is a schematic perspective view of a battery pack including a battery module according to one embodiment of the present invention.

[0133] Referring to FIG. 15, a battery pack (1) according to one embodiment of the present invention may include one or more battery modules (10) according to one embodiment of the present invention as described above. The battery pack (1) according to the present invention may further include a pack case (2) for accommodating a BMS (Battery Management System), a current sensor, a fuse, and the like for integrated control of charging and discharging of one or more battery modules, and the above-described components.

[0134] Alternatively, the battery pack (1) according to the present invention may include the battery module (10) according to the present invention, but may not include a separate pack case (2), and may be configured such that the module case (200) of the battery module (10) functions as the pack case (2). In this case, components of the battery pack, such as a BMS, a bus bar, and a relay, may be included inside the module case (200). A battery pack of this type is also called a cell-to-pack (CTP) in that the battery cells (110) are directly stored in the pack case (2). Recently, development of such CTP-type battery packs has also been active, and the present invention can also be applied to such CTP-type battery packs.

[0135] In particular, a thermal conductive layer (300) is partially provided with different adhesive strengths on the inner surface of the housing, which is the pack case (2) and the module case (200), such as the bottom surface, so that stability against swelling, etc. can be secured. In addition, heat from a plurality of battery cells (110) is directly transferred to the pack case (PC) through the thermal conductive layer (300), so that cooling performance can be further improved.

[0136]

[0137] FIG. 16 is a schematic perspective view of a vehicle including a battery pack according to one embodiment of the present invention.

[0138] Referring to FIG. 16, a vehicle (3) according to an embodiment of the present invention may include one or more battery packs (1) according to an embodiment of the present invention or battery modules (10) according to an embodiment of the present invention. The vehicle (3) according to the present invention may be, for example, an electric vehicle, a hybrid vehicle, or a plug-in hybrid vehicle. The vehicle (3) includes a four-wheel vehicle and a two-wheel vehicle. The vehicle (3) operates by receiving power from the battery packs (1) and / or battery modules (10) according to an embodiment of the present invention.

[0139] Although the present invention has been described above with reference to limited embodiments and drawings, the present invention is not limited thereto, and it is obvious that various modifications and variations can be made within the scope of the technical idea of ​​the present invention and the equivalent scope of the claims to be described below by a person skilled in the art to which the present invention pertains.

Claims

1. A cell stack comprising a plurality of battery cells; a module case configured to accommodate the above cell stack; and A battery module characterized by including a thermally conductive layer provided between the module case and the cell stack and configured to have a difference in adhesive strength from the outside to the inside.

2. In paragraph 1, A battery module characterized in that the thermally conductive layer is configured such that the adhesive strength becomes weaker from the outside to the inside.

3. In paragraph 1, The above thermal conductive layer A first thermally conductive layer configured to be in contact with the above module case, A battery module characterized by including a second heat-conducting layer provided on the inner side of the first heat-conducting layer and configured to be in contact with the cell stack.

4. In paragraph 3, A battery module, characterized in that the first heat-conducting layer and the second heat-conducting layer are configured to have different adhesive strengths.

5. In paragraph 3, A battery module characterized in that the adhesive strength of the second heat-conducting layer is configured to be weaker than the adhesive strength of the first heat-conducting layer.

6. In paragraph 3, A battery module, characterized in that the second heat-conducting layer is formed of a material having a lower hardening degree than the first heat-conducting layer.

7. In paragraph 3, A battery module, characterized in that the second heat-conducting layer is made of a material containing silicon.

8. In paragraph 3, A battery module, characterized in that the second thermally conductive layer is configured to surround the end portion of the battery cell.

9. In paragraph 8, A battery module, characterized in that the second thermally conductive layer is configured to be insertable between the plurality of battery cells when swelling of the battery cells occurs.

10. In paragraph 8, A battery module, characterized in that the first heat-conducting layer is configured to be in contact with an end portion of the battery cell.

11. In paragraph 8, A battery module, characterized in that the first thermally conductive layer is configured to surround the end portion of the battery cell.

12. In paragraph 3, A battery module characterized in that the thermally conductive layer is configured to include a portion in which the thickness of the second thermally conductive layer differs as it goes toward the outermost direction in the stacking direction of the battery cells.

13. A battery pack comprising a battery module according to any one of claims 1 to 12.

14. A vehicle comprising a battery module according to any one of claims 1 to 12.

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