KR20230170251A - Battery module, battery pack and vehicle comprising the same - Google Patents

Abstract

A battery module according to the present invention includes a cell stack in which a plurality of cells are stacked; A U-shaped frame composed of a bottom and two side walls to surround the lower surface and both sides of the cell stack; a top plate located on the upper surface of the cell stack and coupled to the U-shaped frame; and an end plate coupled to the U-shaped frame at the front and rear of the cell stack, wherein the U-shaped frame and the top plate extend in one direction within the metal plate and have a plurality of hollow portions open at both ends isolated from each other. It is characterized by being made of a metal hollow material included.

Description

Battery module, battery pack and vehicle comprising the same}

The present invention relates to a battery module, and more specifically, to a battery module with an improved module case to improve thermal safety. The present invention also relates to battery packs and automobiles including such battery modules.

Secondary batteries, which are easy to apply depending on the product group and have electrical characteristics such as high energy density, are widely applied not only to portable devices, but also to electric vehicles or hybrid vehicles driven by an electrical drive source, and power storage devices. These secondary batteries are attracting attention as a new energy source for improving eco-friendliness and energy efficiency, not only because they have the primary advantage of being able to dramatically reduce the use of fossil fuels, but also because they do not generate any by-products due to energy use.

While small mobile devices use one or two or three to four cells per device, mid- to large-sized devices such as automobiles require high output and large capacity. Therefore, a medium-to-large battery module is used that includes a cell stack in which a plurality of cells are electrically connected. Since it is desirable for mid- to large-sized battery modules to be manufactured in as small a size and weight as possible, rectangular cells and pouch-type cells that can be stacked with high integration and have a small weight-to-capacity ratio are mainly used as unit cells for medium-to-large battery modules, and these cells A plurality of silver modules are provided in a module case and electrically connected to each other to form a battery module. These battery modules become unit modules and are electrically connected to each other to form a battery pack.

Recently, demand for large-capacity battery modules and packs applied to electric vehicles has been increasing. Since these large-capacity battery modules and packs contain a large number of cells, safety must be managed more strictly. If thermal runaway, ignition, or explosion occurs in some cells within one battery module, the generated high-temperature gas, flame, or high-temperature internal materials may be sprayed and transferred to other adjacent cells, which may then be transmitted to other adjacent cells. As it is transmitted to the module, secondary thermal runaway, secondary fire, or explosion may occur, and there is a risk of sequential thermal runaway, ignition, or explosion of multiple cells. Therefore, there is a great need for a means to suppress or delay flame transfer between battery modules when a thermal event such as thermal runaway occurs.

The present invention was created in consideration of the above-mentioned problems, and the technical problem to be solved by the present invention is to provide a battery module with increased safety against thermal runaway, fire, explosion, etc., that is, thermal safety.

However, the technical problem to be solved by the present invention is not limited to the above-mentioned problem, and other problems not mentioned will be clearly understood by those skilled in the art from the description of the invention described below. It could be.

A battery module according to the present invention for solving the above-described problems includes a cell stack in which a plurality of cells are stacked; a U-shaped frame composed of a bottom and two side walls to surround the lower surface and both sides of the cell stack; a top plate located on the upper surface of the cell stack and coupled to the U-shaped frame; and an end plate coupled to the U-shaped frame at the front and rear of the cell stack, wherein the U-shaped frame and the top plate extend in one direction within the metal plate and have a plurality of hollow portions open at both ends isolated from each other. It is characterized by being made of a metal hollow material included.

The cell stack is a body in which a plurality of cells including electrode leads are stacked face-to-face on at least one side in the longitudinal direction, the U-shaped frame surrounds both sides on which the electrode leads are not formed, and the end plate is configured to cover the cells. It may be arranged to face the electrode lead of the laminate.

At this time, the hollow portion may extend along the longitudinal direction.

According to one aspect of the present invention, the hollow portion may be included as a single layer in the hollow metal material.

At this time, in the hollow metal material, the height of the hollow part is 0.3-2mm, the thickness of the metal layer above the hollow part and the thickness of the metal layer below the hollow part are 0.3-1mm, and the spacing between the hollow parts is 0.3-2mm. You can.

According to another aspect of the present invention, the U-shaped frame and the top plate may include a stepped portion on the outer periphery that is relatively thinner than other portions.

For example, the U-shaped frame and the top plate may have flat outer surfaces and the step portion may be formed by an inner depression.

Preferably, the step portion has a structure in which the hollow portion is compressed.

The step portion may be 0.3-2 mm thicker than other portions.

As another example, the step portion may not have the hollow portion and may be formed by cutting the hollow metal material at a right angle.

In the present invention, the stepped portion of the top plate may be seated on the stepped portion of the U-shaped frame.

The width of the step portion of the top plate may be greater than the thickness of the top of the side wall of the U-shaped frame.

The stepped portion of the top plate may be laser welded at a portion that contacts the top of the side wall of the U-shaped frame.

According to the present invention, the end plate may include a protrusion inserted into the hollow portion.

At this time, the protrusion may be inserted into each hollow portion, and the surface of the end plate in contact with the U-shaped frame and the top plate may be laser welded.

In the present invention, an insulating air layer can be formed by the hollow portion.

The hollow metal material may be manufactured by extrusion.

According to another aspect of the present invention, the surface of the hollow metal material may further include a ceramic coating layer made of only inorganic material without organic material.

Meanwhile, the battery pack and vehicle according to the present invention include the battery module according to the present invention as described above.

According to the present invention, by changing the module case, there is an effect of suppressing and delaying the progress of a thermal runaway transition event within a unit module or between modules.

According to the present invention, even if thermal runaway, ignition, or explosion occurs in some cells within one battery module, this is not transmitted to other adjacent battery modules. Therefore, a plurality of cells do not thermally run away, ignite, or explode in succession, and secondary thermal runaway, secondary fire, or explosion does not occur.

Therefore, according to the present invention, even if thermal runaway, fire, or explosion occurs in some of the plurality of cells, the thermal runaway, fire, or explosion may not spread to other adjacent battery modules. Therefore, it is possible to provide a battery module with improved safety against thermal runaway, fire, explosion, etc., that is, thermal safety, and a pack and vehicle containing the same.

The following drawings attached to this specification illustrate preferred embodiments of the present invention, and serve to further understand the technical idea of the present invention together with the detailed description of the invention described later, so the present invention includes the matters described in such drawings. It should not be interpreted as limited to only .
1 is an exploded perspective view showing a battery module according to an embodiment of the present invention.
FIG. 2 is a perspective view showing a state in which the components constituting the battery module of FIG. 1 are combined.
Figure 3 is a diagram showing a battery cell applied to a battery module according to an embodiment of the present invention.
Figure 4 is a cross-sectional view taken along line A-A' in Figure 2.
Figure 5 is an enlarged view of portion B of Figure 4.
Figure 6 is an enlarged view of part C of Figure 4.
Figure 7 is an enlarged view of portion D of Figure 2.
Figure 8 is another enlarged view of portion C of Figure 4.
Figure 9 is a schematic diagram showing a battery pack according to an embodiment of the present invention.
Figure 10 is a schematic diagram showing a vehicle according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. Prior to this, the terms or words used in this specification and claims should not be construed as limited to their usual or dictionary meanings, and the inventor should appropriately define the concept of terms in order to explain his or her invention in the best way. It must be interpreted as meaning and concept consistent with the technical idea of the present invention based on the principle of definability. Accordingly, the embodiments described in this specification and the configurations shown in the drawings are only some of the most preferred embodiments of the present invention and do not represent the entire technical idea of the present invention, so at the time of filing the present application, various options that can replace them are available. It should be understood that equivalents and variations may exist.

1 is an exploded perspective view showing a battery module according to an embodiment of the present invention. FIG. 2 is a perspective view showing a state in which the components constituting the battery module of FIG. 1 are combined. Figure 3 is a diagram showing a battery cell applied to a battery module according to an embodiment of the present invention.

Referring to FIGS. 1 to 3 , a battery module 90 according to an embodiment of the present invention includes a cell stack 100 and a module case 200.

The cell stack 100 is a stack of a plurality of cells 110. The module case 200 includes a U-shaped frame 210, a top plate 220, and an end plate 230.

The cell stack 100 may be a collection of secondary batteries composed of pouch-type cells 110 stacked with their wide sides facing each other. More precisely, the cell stack 100 is a secondary battery in which cells 110 are stored vertically (along the Z-axis direction) and stacked horizontally (along the Y-axis direction) in the module case 200. It may be a collection of them. The pouch-type cells 110 have the advantage of being easy to stack while having a high energy density compared to their size and weight. However, the cells 110 included in the battery module 90 according to the present invention are not limited to pouch-type cells, and various types of secondary batteries known at the time of filing the present application may be employed.

The U-shaped frame 210 is composed of a bottom surface 212 and two side walls 214 to cover the lower surface and both sides of the cell stack 100. The U-shaped frame 210 accommodates the cell stack 100 and has an open top. The U-shaped frame 210 has the advantage of being easy to handle when mounting the cell stack 100 and assembling the battery module 90 because the top, front, and back are open.

The top plate 220 is located on the upper surface of the cell stack 100 and is coupled to the U-shaped frame 210. Joining may be by either welding, gluing, or bolting. The top plate 220 covers the cell stack 100 on the U-shaped frame 210.

The end plate 230 is coupled to the U-shaped frame 210 at the front and rear of the cell stack 100. The end plate 230 may also be combined with the top plate 220. The joining here can also be done by any one of welding, adhesion, or bolting. End plates 230 may be positioned on the front and rear sides of the cell stack 100, respectively. In addition, the battery module 90 may further include a bus bar frame 240 located between the cell stack 100 and the end plate 230.

When the open sides of the U-shaped frame 210 are referred to as the first side and the second side, respectively, the U-shaped frame 210 has the surfaces of the cell stack 100 corresponding to the first side and the second side. Except for the remaining outer surfaces, it is composed of a plate-shaped structure folded to continuously cover the front, bottom, and rear surfaces adjacent to each other. In other words, it has a structure in which both ends of a plate-shaped member are folded vertically. The upper surface corresponding to the lower surface of the U-shaped frame 210 is open. A thermally conductive resin layer 216 may be formed on the bottom surface 212 of the U-shaped frame 210.

The upper plate 220 has a plate-shaped structure so as to surround the upper surface of the cell stack 100 that is not surrounded by the U-shaped frame 210. The U-shaped frame 210 and the upper plate 220 may be joined by laser welding or the like, with their corresponding corners in contact, to form a structure surrounding the cell stack 100. That is, the U-shaped frame 210 and the upper plate 220 may be joined to each other at corresponding corners using a joining method such as laser welding to form a welded portion CP. That is, a welded portion CP may be formed at the top of the side wall 214 and the edge of the upper plate 220 of the U-shaped frame 210.

As the cell 110, a pouch-type cell may be applied, as mentioned above. When the cell 110 is a pouch-type cell, as shown in FIG. 3, the cell 110 includes an electrode assembly (not shown), a pouch case 111, an electrode lead 112, and a sealing tape 113. It can be implemented in the form of:

Although not shown in the drawing, the electrode assembly has a separator interposed between alternately and repeatedly stacked positive and negative electrode plates, and it is preferable that separators are located on the outermost surfaces of both sides for insulation.

The positive electrode plate consists of a positive electrode current collector and a positive electrode active material layer coated on one side of the positive electrode collector, and a positive electrode uncoated area that is not coated with the positive electrode active material is formed at one end. This positive electrode uncoated area functions as a positive electrode tab. do.

The negative electrode plate consists of a negative electrode current collector and a negative electrode active material layer coated on one or both sides of the negative electrode plate, and a negative electrode uncoated area that is not coated with the negative electrode active material is formed at one end. This negative electrode non-coated area is a negative electrode non-coated area. Functions as a tab.

In addition, the separator is interposed between the positive and negative electrode plates to prevent direct contact between electrode plates with different polarities, but may be made of a porous material to enable the movement of ions between the positive and negative electrode plates using the electrolyte as a medium. there is.

The cell case 111 includes an accommodating portion 111a that accommodates the electrode assembly and extends in the circumferential direction of the accommodating portion 111a and is heat-sealed and sealed with the electrode lead 112 drawn out. It includes two areas: a sealing portion 111b that seals the .

Although not shown in the drawing, the cell case 111 is sealed by heat-sealing the edge portions of the upper and lower cases in contact with each other, which is made of a multi-layer pouch film in which a resin layer/metal layer/resin layer is sequentially laminated. The upper case and lower case may be made of two sheets separated from each other or one sheet that is not separated from each other folded.

A pair of electrode leads 112 are connected to a positive electrode tab (not shown) and a negative electrode tab (not shown), respectively, and are drawn out to the outside of the cell case 111. The pair of electrode leads 112 may have a structure that faces each other and protrudes from one end and the other end of the cell 110, respectively. The distance between both ends of the cell case 111 where the electrode leads 112 protrude may be defined in the longitudinal direction of the cell 110 (X-axis direction in this embodiment). In other types of pouch-type cells, electrode leads may be formed on only one side. In this way, the cell 110 may include an electrode lead 112 on at least one side in the longitudinal direction.

The sealing tape 113 is attached to the circumference of the electrode lead 112 and is interposed between the electrode lead 112 and the inner surface of the sealing portion 111b of the pouch case 111. The sealing tape 113 prevents the sealing property of the sealing portion 111b from becoming vulnerable due to the withdrawal of the electrode lead 112.

A plurality of cells 110 may be stacked in the Y-axis direction as shown in FIG. 1. A plurality of cells 110 may be stacked face to face. If the surface of the cell case 111 is slippery, it tends to slip easily due to external impact when a plurality of cells 110 are stacked. Therefore, in order to prevent this and maintain a stable stacked structure of the cells 110, an adhesive member such as an adhesive such as a double-sided tape or a chemical adhesive that is bonded by a chemical reaction during adhesion is attached to the surface of the cell case 111. Thus, the cell stack 100 can be formed. In this embodiment, the cell stack 100 is stacked in the Y-axis direction and accommodated inside the U-shaped frame 210 in the Z-axis direction, so that cooling can occur by the thermally conductive resin layer 216. In a structure in which cells are contained in cartridge-shaped components and stacked, due to the presence of cartridge-shaped components, cooling may be minimal or may proceed in the direction of the surface of the cell, and cooling may not occur well in the height direction of the battery module. The battery module 90 according to an embodiment of the present invention is well cooled in the height direction (Z-axis direction) of the battery module.

Before the cell stack 100 is mounted on the bottom surface 212 of the U-shaped frame 210, a thermally conductive resin is applied to the bottom surface 212 of the U-shaped frame 210, and the thermally conductive resin is cured. The thermally conductive resin layer 216 shown in FIG. 1 can be formed. Before forming the thermally conductive resin layer 216, that is, before the applied thermally conductive resin is cured, the cell stack 100 moves along a direction perpendicular to the bottom surface 212 of the U-shaped frame 210. It can be mounted on the bottom surface 212 of the U-shaped frame 210. Afterwards, the thermally conductive resin layer 216 formed by curing the thermally conductive resin is positioned between the bottom surface 212 of the U-shaped frame 210 and the cell stack 100. The thermally conductive resin layer 216 may transfer heat generated from the cell 110 to the bottom of the battery module 90 and serve to secure the cell stack 100. Through the thermally conductive resin layer 216, heat generated from the plurality of cells 110 may be transferred to the outside through the bottom surface 212 of the U-shaped frame 210. The thermally conductive resin layer 216 may include thermal resin. As the thermally conductive resin layer 216, urethane resin, epoxy resin, or silicone resin, etc., which have excellent thermal conductivity and adhesiveness, may be used. This material permeates between the cells 110 and eliminates the air layer, thereby reducing thermal resistance, and also has adhesive properties to prevent the flow of the cells 110 and stably support the lower part of the cell stack 100. The battery module 90 may be placed on the heat sink so that the bottom surface 212 of the U-shaped frame 210 is in contact with the heat sink (not shown). The heat of the cells 110 involved in the charging and discharging process can be quickly dissipated through the thermally conductive resin layer 216, the bottom surface 212 of the U-shaped frame 210, and the heat sink.

The U-shaped frame 210 surrounds both sides of the cell stack 100 where the electrode leads 112 are not formed and the lower surface of the cell stack 100. The end plate 230 is disposed to face the electrode lead 112 of the cell stack 100. This module case 200, which includes a U-shaped frame 210, a top plate 220, and an end plate 230, has an internal space for storing cells 110 therein, and the stored cells 110 It provides mechanical support and protects against external shocks. The battery module 90 of the present invention is particularly improved in the module case 200 portion.

Figure 4 is a cross-sectional view taken along line A-A' in Figure 2. Figure 5 is an enlarged view of portion B of Figure 4. Figure 6 is an enlarged view of part C of Figure 4.

4 to 6, in the battery module 90, the U-shaped frame 210 and the top plate 220 have a hollow portion 224 that extends in one direction and is open at both ends within the metal plate 222. It is characterized by being made of a plurality of hollow metal materials that are isolated from each other. Here, the metal is preferably aluminum (Al) or aluminum alloy. In this case, a U-shaped frame 210 and top plate 220 with excellent strength and lightness can be obtained.

In this embodiment, the hollow portion 224 extends along the longitudinal direction. The hollow portion 224 extends in a direction parallel to the pair of electrode leads 112. Since the hollow portion 224 extends along the protruding direction of the electrode lead 112, which generates relatively high heat in each cell 110, it is excellent in blocking heat transfer between each cell 110.

As shown in detail in FIG. 5, the hollow portion 224 in the hollow metal material may be included as a single layer. To further increase the energy density of the battery module 90, it is necessary to reduce the thickness of the U-shaped frame 210 and the top plate 220. In order for the hollow portion 224 to be included as a multi-layer while maintaining the required strength of the U-shaped frame 210 and the top plate 220, the thickness of the U-shaped frame 210 and the top plate 220 must be increased, so they are included as a single layer. This is desirable. An insulating air layer may be formed by the hollow portion 224. That is, the hollow portion 224 is not filled with a separate refrigerant or additional member. It utilizes the high insulation properties of the air layer without the need for a separate refrigerant circulation means or additional members. The hollow part 224 does not attempt to cool, but rather blocks heat transfer. As a result, even when there is a temperature change inside the battery module 90, heat transfer to the outside is blocked, and as a result, heat propagation to neighboring battery modules is blocked to prevent chain thermal events from occurring in the battery module. Safety can be improved.

The cross-sectional structure of the U-shaped frame 210 and the top plate 220 is such that the rectangular hollow portion 224 is contained in a single layer in the middle of the metal plate 222, and the shape of the hollow portion 224 and the hollow portion ( The distance between the hollow portions 224 is constant, and the height h of the hollow portion 224 is equal to or greater than the metal layer thickness d1 above the hollow portion 224 and the metal layer thickness d2 below the hollow portion 224. big. These height (h) and thickness (d1, d2) conditions maintain the rigidity of the U-shaped frame 210 and the top plate 220 while increasing the volume occupied by the hollow portion 224 as much as possible to prevent heat spread. It is suitable.

The previously known module case is a simple structure (solid type) in which the entire cross-sectional structure is filled with metal such as Al or SUS, and there is a problem of thermal runaway spreading to neighboring battery modules by external or internal heat conduction. In other words, the existing module case is unable to prevent heat conduction and radiation when an event such as thermal runaway propagation occurs, resulting in flames being transferred to neighboring battery modules. In the battery module 90 of the present invention, by changing the cross-sectional structure of the module case 200 as described above, flame can be prevented from transferring between battery modules when an event such as thermal runaway propagation occurs.

Most preferably, the U-shaped frame 210 and the top plate 220 extend in one direction (in this embodiment, the longitudinal direction, the It can be defined as a hollow cross-section that includes a plurality of parts 224 isolated from each other to form an insulating air layer to minimize thermal runaway such as heat conduction and heat radiation.

The hollow metal material may be manufactured by extrusion. The U-shaped frame 210 can be manufactured by folding an extruded plate-shaped member of an appropriate size or a cut to an appropriate size. The top plate 220 can be manufactured by itself using a plate-shaped member of an appropriate size that has been extruded or cut to an appropriate size. The hollow portion 224 along the extrusion direction has an elongated extension shape, and neighboring hollow portions 224 are formed side by side along the extrusion direction. Compared to a case where the hollow structure exists in a disorderly manner, such as a metal foam, the hollow metal material to be used in the present invention has a difference in that it has a regular arrangement of the hollow structure, and the height (h) of the hollow portion 224 and the hollow structure are Since the hollow portion 224 can be provided while controlling the spacing (p) between the portions 224, etc., precise control and management of the insulation effect is possible.

According to a preferred example, the height (h) of the hollow part 224 in the hollow metal material is 0.3-2 mm, the metal layer thickness (d1) above the hollow part 224 and the metal layer thickness below the hollow part 224 ( d2) is 0.3-1 mm, and the gap (p) between the hollow parts 224 may be 0.3-2 mm. The thickness (D) of the hollow metal material may be 1.5-4 mm. If the height (h) of the hollow portion 224 or the spacing (p) between the hollow portions 224 is less than 0.3 mm, the size of the hollow portion 224 becomes too small and the spacing becomes tight, making it difficult to sufficiently exert an insulating effect. If the height (h) of the hollow portion 224 or the spacing (p) between the hollow portions 224 is greater than 2 mm, it is not desirable in terms of including as many hollow portions 224 as possible in a given space. If the metal layer thickness (d1) above the hollow part 224 and the metal layer thickness (d2) below the hollow part 224 are less than 0.3 mm, the U-shaped frame 210 and the top plate 220 can be made thin and light while maintaining rigidity. is difficult to secure. If the metal layer thickness d1 above the hollow portion 224 and the metal layer thickness d2 below the hollow portion 224 are greater than 1 mm, it is not desirable in terms of containing the hollow portion 224 as large as possible within a given space. not. If the thickness (D) of the hollow metal material is less than 1.5 mm, it is difficult to secure the rigidity of the U-shaped frame 210 and the top plate 220. If the thickness (D) of the hollow metal material is greater than 4 mm, it is undesirable because the size and weight of the battery module 90 increase.

Here, the height (h), thickness (d1, d2, D), and spacing (p) are variable. The height (h), thickness (d1, d2, D), and gap (p) are very small values compared to the external size of the battery module 90, which is hundreds of mm x hundreds of mm. It should be understood that the scale is different from that of forming a flow path in the module case itself. Also, considering that the height (h) of the hollow portion 224 and the spacing (p) between the hollow portions 224 are 0.3-2 mm, it can be said that the fine hollow portions 224 are densely formed. If the thickness (D) of the hollow metal material is set to 1.5-4 mm and the height (h) of the hollow part 224 and the gap (p) between the hollow parts 224 are set to 0.3-2 mm, the U-shaped frame 210 and the tower Rigidity can be secured while making the plate 220 thin and light, and the insulation effect can be maximized by including as many hollow parts 224 as possible within a given space.

In order to further increase the energy density of the battery module 90, it is necessary to reduce the thickness of the U-shaped frame 210 and the top plate 220, but when extruding a thin hollow metal material, the input amount of molding material Compared to this, the amount drawn out and molded is too small, and as the thickness of the hollow metal material becomes thinner, the pressure applied for extrusion increases, raising the risk of damage to the extrusion mold. Additionally, as the thickness of the hollow metal material becomes thinner, problems such as distorted shape of the molded product or uneven thickness may occur. Therefore, taking all of these issues into consideration, the height (h), thickness (d1, d2, D), and spacing (p) can be determined. Through variable control during extrusion manufacturing, the height (h) of the hollow portion 224 is equal to or equal to the metal layer thickness d1 above the hollow portion 224 and the metal layer thickness d2 below the hollow portion 224. In comparison, it can be formed large, and the gap p between the hollow parts 224 can be formed very densely. Therefore, there is an advantage that the thermal insulation effect is excellent.

In the battery module 90, hollow portions 224 are located on the lower surface, both sides, and the upper surface of the cell stack 100. Since the hollow portions 224 are located on all sides of the cell stack 100, the effect of blocking heat propagation in all directions can be maximized.

The U-shaped frame 210 and the top plate 220 may form a welded portion (CP) by simple butt welding, but as shown in detail in FIG. 6, the step portions 210a and 220a are formed and then welded. It is desirable.

Referring to FIG. 6, the U-shaped frame 210 includes a step portion 210a on the outer periphery that is relatively thinner than other portions. The step portion 210a is provided at the top of the side wall 214 of the U-shaped frame 210. The top plate 220 includes a step portion 220a on the outer periphery that is relatively thinner than other portions. The step portion 220a is provided at the edge of the top plate 220. The U-shaped frame 210 and the top plate 220 have flat outer surfaces, and the step portions 210a and 220a may be formed by inner depressions.

Preferably, the step portions 210a and 220a have a structure in which the hollow portion 224 is compressed. In such a case, the step portions 210a and 220a have a thickness limited to the height h of the hollow portion 224 in the hollow metal material, so the step portions 210a and 220a have a thickness greater than that of the other portions of the hollow portion. It can be as thin as 0.3-2 mm, which is the height (h) of (224). Since the hollow portion 224 can be easily crushed even if the crushing force is not large, the step portions 210a and 220a can be easily and precisely formed through compression processing.

As another example, the step portions 210a and 220a may not have a hollow portion 224 and may be formed by cutting the hollow metal material at a right angle.

The step portion 220a of the top plate 220 may be seated on the step portion 210a of the U-shaped frame 210. The portion where the step portion 220a of the top plate 220 contacts the top of the side wall 214 of the U-shaped frame 210 may be laser welded. In other words, the hollow part can be compressed and crushed, and then the part can be welded to form a welded portion (CP). By applying the step portions 210a and 220a, the welding area can be increased, and thus the bonding force due to welding can be increased. Even if the thin U-shaped frame 210 and top plate 220 are applied, appropriate rigidity can be secured, so the battery module 90 with increased product yield and improved energy density can be provided.

The width (W) of the step portion 220a of the top plate 220 may be greater than the upper thickness (L) of the side wall 214 of the U-shaped frame 210. Accordingly, durability against external forces can be strengthened, and effects such as blocking internal penetration of the laser beam during laser welding can be achieved. When the laser beam passes through the side wall 214 of the U-shaped frame 210 and penetrates the inside, the cell stack 100 and other internal structures may be damaged. According to the present invention, by appropriately designing the step portions 210a and 220a, the laser beam can be blocked from penetrating inside, thereby improving the productivity of the battery module 90.

Figure 7 is an enlarged view of portion D of Figure 2.

The end plate 230 includes a protrusion 232 inserted into the hollow portion 224 of the U-shaped frame 210. The protrusion 232 may have a shape corresponding to the hollow portion 224. For example, if the hollow portion 224 has a rectangular cross-section, the protrusion 232 may be shaped like a rectangular parallelepiped pillar. As another example, if the hollow portion 2240 has a circular cross-section, the protrusion 232 may be cylindrical. The protrusion 232 is inserted into each hollow portion 224 and the end plate 230 is connected to the U-shaped frame 210. The surface in contact with the top plate 220 may be laser welded. The U-shaped frame 210 and the top plate 220 have a hollow portion 224. To supplement the thickness of the flesh around the hollow portion 224. By adding protrusions 232 to the welded portion of the end plate 230, welding rigidity can be secured by matching the protrusions 232 to the hollow portion 224. Included in the U-shaped frame 210 and the top plate 220. The hollow part 224, which is open at both ends, may be closed at both ends by the end plate 230. Therefore, an insulating air layer is maintained in the hollow part 224, and the hollow part 224 is exposed to the outside. The intrusion of foreign substances into the interior can be blocked.

Figure 8 is another enlarged view of portion C of Figure 4.

According to another aspect of the present invention, the surface of the hollow metal material may further include a ceramic coating layer 226 made of only inorganic material without organic material. The ceramic coating layer 226 may be formed on only one surface of the hollow metal material, for example, on the outer side, or on both surfaces, for example, on both the outer and inner sides.

The ceramic coating layer 226 is a refractory coating. The previously known ceramic coating is an organic material (for example, fluoropolymer) that is coated with ceramic in the form of some additives. In the present invention, an eco-friendly and high-performance ceramic coating layer 226 is used because it contains no organic matter and ceramics are the main raw material. The ceramic coating layer 226 can be formed by applying a coating containing ceramic powder and curing it naturally or at a low temperature of around 200°C. In other words, the battery module 90 of the present invention further includes a fire-resistant coating layer on the outer or inner wall of the module case 200, and this fire-resistant coating layer is an eco-friendly ceramic coating layer 226 that has been applied and hardened.

The coating agent may be a slurry obtained by mixing fine ceramic powders such as alumina and silica with water and an inorganic dispersant. It may further include inorganic oxides (K ₂ O, BaO, etc.) that enable the formation of glass. However, this slurry does not contain organic solvents or organic binders. If it contains organic solvents and organic binders, heat resistance is low and the coating deteriorates over time after formation. In the present invention, this slurry-type coating agent can be applied to the surface of a hollow metal material and cured to form the ceramic coating layer 226. Application may be performed using any method such as dip coating, spin coating, spray coating, or brushing. This slurry-type coating agent can be coated directly on metal to achieve low-temperature fusion, is environmentally friendly, is harmless to the human body, and has excellent corrosion resistance, wear resistance, and adhesion.

The ceramic coating layer 226 can block flames of over 1000°C. Accordingly, flame spread to neighboring battery modules can be blocked. Additionally, the ceramic coating layer 226 can further improve the durability of the battery module 90.

Meanwhile, the battery pack and vehicle according to the present invention include the battery module according to the present invention as described above.

Figure 9 is a schematic diagram showing a battery pack according to an embodiment of the present invention. Figure 10 is a schematic diagram showing a vehicle according to an embodiment of the present invention.

The battery module 90 described above and the battery pack 300 including it can be applied to various devices. These devices are typically transportation means such as electric bicycles, electric cars, and hybrid cars, but the present invention is not limited thereto. This battery pack 300 is suitable for use as a battery pack for electric vehicles. Additionally, it can be used as an energy source for an electric power storage device (ESS).

9 and 10, the battery pack 300 may include at least one battery module 90 according to the previous embodiment and a pack case 310 packaging the at least one battery module 90. there is.

In addition to the battery module 90 and the pack case 310, the battery pack 300 according to the present invention includes various devices for controlling charging and discharging of the battery module 90, such as a battery management system (BMS), and a current Additional sensors, fuses, etc. may be included.

The battery modules 90 form a substantially rectangular parallelepiped shape and can be arranged in an orderly manner within the battery pack case 310, and each battery module 90 is connected to secure the power necessary for running the vehicle 400. there is.

The battery pack case 310 is a container that fixedly stores the battery modules 90 and is a box in the shape of a rectangular parallelepiped. And, this battery pack case 310 can be placed at a predetermined location within the vehicle 400.

Preferably, the vehicle 400 may be an electric vehicle. The battery pack 300 can be used as an electrical energy source to drive the vehicle 400 by providing driving force to the motor of the electric vehicle. In this case, the battery pack 300 has a high nominal voltage of 100V or more.

The battery pack 300 may be charged or discharged by an inverter according to the driving of the motor and/or internal combustion engine. The battery pack 300 can be charged by a regenerative charging device combined with a brake. The battery pack 300 may be electrically connected to the motor of the vehicle 400 through an inverter. In addition, of course, the battery pack 300 may be installed in other devices, instruments, and facilities, such as an electric power storage system (ESS) using secondary batteries, in addition to the above-mentioned automobile.

In this way, the battery pack 300 and the device, mechanism, and equipment provided with the battery pack 300, such as the car 400 according to this embodiment, include the battery module 90 described above, and the battery described above. It is possible to implement devices, mechanisms, and equipment such as a battery pack 300 that has all the advantages of the module 90 and a car 400 equipped with the battery pack 300.

Meanwhile, in this specification, terms indicating directions such as up, down, front, and back are used, but these terms are only for convenience of explanation and may vary depending on the location of the object or the location of the observer. It is obvious to those with ordinary knowledge in the technical field to which the invention belongs.

Above, preferred embodiments of the present invention have been shown and described, but the present invention is not limited to the specific preferred embodiments described above, and the technology to which the invention pertains without departing from the gist of the present invention as claimed in the claims. Anyone skilled in the art can make various modifications, and such modifications fall within the scope of the claims.

90: Battery module 100: Cell stack
110: cell 111: cell case
111a: receiving part 111b: sealing part
112: electrode lead 113: sealing tape
200: module case 210: U-shaped frame
210a, 220a: step portion 212: bottom surface
214: side wall 216: thermally conductive resin layer
220: upper plate 222: metal plate
224: hollow part 230: end plate
232: Protrusion 240: Busbar frame
CP: welding area 300: battery pack

Claims (20)

A cell stack in which a plurality of cells are stacked;
a U-shaped frame composed of a bottom and two side walls to surround the lower surface and both sides of the cell stack;
a top plate located on the upper surface of the cell stack and coupled to the U-shaped frame; and
It includes an end plate coupled to the U-shaped frame at the front and rear of the cell stack,
A battery module, wherein the U-shaped frame and the top plate are made of a hollow metal material that extends in one direction within the metal plate and includes a plurality of hollow portions that are open at both ends and are isolated from each other. The cell stack according to claim 1, wherein a plurality of cells including electrode leads are stacked face to face on at least one side in the longitudinal direction,
The U-shaped frame surrounds both sides on which the electrode leads are not formed,
A battery module, wherein the end plate is disposed to face the electrode lead of the cell stack. The battery module of claim 2, wherein the hollow portion extends along the longitudinal direction. The battery module according to claim 1, wherein the hollow portion is included as a single layer in the hollow metal material. The method of claim 4, wherein in the hollow metal material, the height of the hollow portion is 0.3-2 mm, the thickness of the metal layer above the hollow portion and the thickness of the metal layer below the hollow portion are 0.3-1 mm, and the spacing between the hollow portions is 0.3 mm. A battery module characterized in that it is -2mm. The battery module according to claim 1, wherein the U-shaped frame and the top plate include a stepped portion on an outer periphery that is relatively thinner than other portions. The battery module according to claim 6, wherein the U-shaped frame and the top plate have flat outer surfaces and the step portion is formed by an inner depression. The battery module according to claim 6, wherein the stepped portion has a structure in which the hollow portion is compressed. The battery module of claim 8, wherein the stepped portion is 0.3-2 mm thinner than other portions. The battery module according to claim 6, wherein the stepped portion does not have the hollow portion and the hollow metal material is cut at a right angle. The battery module according to claim 6, wherein the stepped portion of the top plate is seated on the stepped portion of the U-shaped frame. The battery module of claim 6, wherein the width of the stepped portion of the top plate is greater than the thickness of the top of the side wall of the U-shaped frame. The battery module according to claim 6, wherein the stepped portion of the top plate is laser welded at a portion that contacts the top of the side wall of the U-shaped frame. The battery module of claim 1, wherein the end plate includes a protrusion inserted into the hollow portion. The battery module according to claim 14, wherein the protrusion is inserted into each hollow portion and the surface of the end plate in contact with the U-shaped frame and the top plate is laser welded. The battery module according to claim 1, wherein an insulating air layer is formed by the hollow portion. The battery module according to claim 1, wherein the hollow metal material is manufactured by extrusion. The battery module according to claim 1, further comprising a ceramic coating layer made of only inorganic material without organic material on the surface of the hollow metal material. A battery pack comprising the battery module according to any one of claims 1 to 18. A vehicle comprising the battery module according to any one of claims 1 to 18.

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