Battery pack and device including same

Abstract

A battery pack according to an embodiment of the present invention includes a battery cell stack in which a plurality of battery cells are stacked, a battery module including a first side plate and a second side plate located on both sides of the battery cell stack and a connecting member disposed on an upper and lower part of the battery cell stack to connect the first side plate and the second side plate; a pack tray for accommodating the battery module; and a heat sink including at least one cooling part through which a refrigerant flows. The heat sink includes at least one of an upper heat sink located on an upper part of the battery module or a lower heat sink located on a lower part of the battery module. The first side plate and the second side plate are fixed to the pack tray. The cooling part of the upper heat sink is located on one side of the connecting member at an upper part of the battery module, and the cooling part of the lower heat sink is located on one side of the connecting member at a lower part of the battery module.

Description

[Technical field]

[0001] [Cross-reference to related applications] This application claims the benefit of priority to Korean Patent Application No. 10-2022-0030046 filed on March 10, 2022, and Korean Patent Application No. 10-2023-0031250 filed on March 9, 2023, and all contents disclosed in the documents of said Korean patent applications are incorporated herein by reference.

[0002] The present invention relates to a battery pack and a device including the same, and more specifically to a battery pack with improved cooling performance and a device including the same. [Background technology]

[0003] In modern society, as the use of portable devices such as mobile phones, laptops, camcorders, and digital cameras has become commonplace, the development of technologies related to these mobile devices is progressing vigorously. In addition, rechargeable secondary batteries are used as the power source for electric vehicles (EVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (P-HEVs), etc., as a solution to resolve air pollution caused by existing gasoline-powered vehicles that use fossil fuels, so there is an increasing need for the development of secondary batteries.

[0004] Currently, commercially available secondary batteries include nickel-cadmium batteries, nickel-metal hydride batteries, nickel-zinc batteries, and lithium secondary batteries. Among these, lithium secondary batteries are attracting attention due to their advantages over nickel-based secondary batteries, such as almost no memory effect, freedom in charging and discharging, a very low self-discharge rate, and high energy density.

[0005] Such lithium secondary batteries mainly use lithium-based oxides and carbon materials as positive and negative active materials, respectively, and include an electrode assembly in which positive and negative electrode plates coated with the positive and negative active materials are disposed with a separator between them, and a battery case that hermetically houses the electrode assembly together with an electrolyte.

[0006] Generally, lithium secondary batteries can be classified into can-type secondary batteries, in which an electrode assembly is incorporated in a metal can, and pouch-type secondary batteries, in which an electrode assembly is incorporated in a pouch made of an aluminum laminate sheet, depending on the shape of the exterior material.

[0007] In the case of secondary batteries used in small devices, two to three battery cells are arranged, whereas in the case of secondary batteries used in medium to large devices such as automobiles, a battery module in which a number of battery cells are electrically connected is used. In such battery modules, a number of battery cells are connected to each other in series or parallel to form a battery cell stack, thereby improving capacity and output. In addition, one or more battery modules may be attached with various control and protection systems such as a BDU (Battery Disconnect Unit), a BMS (Battery Management System), and a cooling system to form a battery pack.

[0008] When constructing a battery pack, it is common to first construct a battery module, and then add various control and protection systems such as a battery disconnect unit (BDU), a battery management system (BMS), and a cooling system to the battery module to construct the battery pack. In the case of a conventional battery pack, the battery module is disposed in a housing structure such as a pack tray before manufacturing, and the battery pack is installed in a vehicle or the like.

[0009] If the temperature of a secondary battery rises above the appropriate level, the performance of the secondary battery may deteriorate, and in extreme cases, there may be a risk of explosion or fire. In particular, in a battery module or battery pack having a large number of secondary batteries, i.e., battery cells, the temperature may rise rapidly and excessively due to the heat generated from the large number of battery cells being combined in a small space. In other words, a battery module in which a large number of battery cells are stacked and a battery pack to which such a battery module is attached can obtain high output, but it is difficult to remove the heat generated in the battery cells during charging and discharging. If the heat of the battery cells is not properly dissipated, the battery cells will deteriorate quickly, shortening their lifespan and increasing the possibility of explosion or fire.

[0010] Furthermore, battery modules included in vehicle battery packs are frequently exposed to direct sunlight and may be placed in high temperature conditions such as in summer or in desert regions. Therefore, when configuring a battery module or battery pack, it can be said that it is very important to ensure stable and efficient cooling performance. Cooling methods for battery modules and battery packs can be broadly divided into water-cooling methods that use a refrigerant such as cooling water and air-cooling methods that use cooling air. Among them, water-cooling cooling has excellent cooling performance and can effectively cool high heat generated in large-capacity battery modules and battery packs.

[0011] Recently, there has been an increasing need for a battery pack structure that can increase energy density and reduce weight to reduce the overall weight, and can maximize cooling performance by effectively arranging a water-cooling structure. Summary of the Invention [Problem to be solved by the invention]

[0012] An object of the present invention is to provide a battery pack and a device including the same that can increase energy density, reduce weight, and improve cooling performance in a limited space.

[0013] However, the problem to be solved by the embodiments of the present invention is not limited to the above problem, and can be variously expanded within the scope of the technical ideas included in the present invention. [Means for solving the problem]

[0014] A battery pack according to an embodiment of the present invention includes a battery cell stack in which a plurality of battery cells are stacked, a battery module including a first side plate and a second side plate located on both sides of the battery cell stack and a connecting member disposed on an upper and lower part of the battery cell stack to connect the first side plate and the second side plate; a pack tray for accommodating the battery module; and a heat sink including at least one cooling part through which a refrigerant flows. The heat sink includes at least one of an upper heat sink located on an upper part of the battery module or a lower heat sink located on a lower part of the battery module. The first side plate and the second side plate are fixed to the pack tray. The cooling part of the upper heat sink is located on one side of the connecting member at an upper part of the battery module, and the cooling part of the lower heat sink is located on one side of the connecting member at a lower part of the battery module.

[0015] The plurality of connecting members may be provided at least at one of an upper side and a lower side of the battery cell stack, and may be spaced apart from each other in a direction perpendicular to a stacking direction in which the battery cells are stacked.

[0016] The cooling portion may be disposed in a space between the connecting members spaced apart from each other.

[0017] The connecting member may be provided singly at least one of an upper side and a lower side of the battery cell stack.

[0018] The battery module may be configured in plurality, and at least two battery modules may be arranged along a stacking direction in which the battery cells are stacked.

[0019] The cooling portion may pass through one side of the connecting member of any one battery module and pass through one side of the connecting member of another battery module adjacent to the any one battery module.

[0020] The cooling unit may include a first cooling unit and a second cooling unit extending in one direction. Each of the upper heat sink and the lower heat sink may further include an inlet portion connected to the first cooling unit and into which a refrigerant flows, an outlet portion connected to the second cooling unit and from which the refrigerant flows, and a connector connecting the first cooling unit and the second cooling unit.

[0021] The coolant may flow along the inlet portion, the first cooling portion, the connecting portion, the second cooling portion, and the outlet portion to form a circulation structure.

[0022] The one direction may be a direction parallel to a stacking direction in which the battery cells are stacked.

[0023] The inlet and the outlet may be located on the same side of the battery module, and the connection portion may be located on an opposite side to the inlet and the outlet.

[0024] The battery module may further include a thermal resin layer located between the cooling portion and the battery cell stack.

[0025] The thermal resin layer may include at least one of an upper thermal resin layer positioned between the cooling portion of the upper heat sink and the battery cell stack, and a lower thermal resin layer positioned between the cooling portion of the lower heat sink and the battery cell stack.

[0026] Each of the first side plate and the second side plate may support an outermost battery cell of the battery cell stack and may include a support portion disposed perpendicular to a bottom portion of the pack tray and a fixing portion protruding in a direction perpendicular to one surface of the support portion. The fixing portion may be fixed to the pack tray.

[0027] The pack tray may include a mounting beam disposed on an upper surface of the bottom portion of the pack tray, and the fastener may be secured to the mounting beam.

[0028] The battery cell stack may include a first battery cell stack and a second battery cell stack, and the first battery cell stack and the second battery cell stack may be arranged apart from each other along a direction perpendicular to a stacking direction in which the battery cells are stacked.

[0029] The first side plate may extend to fully cover one side of the first battery cell stack and one side of the second battery cell stack, and the second side plate may extend to fully cover the other side of the first battery cell stack and the other side of the second battery cell stack.

[0030] The battery module may further include an insulating plate located between the first battery cell stack and the second battery cell stack.

[0031] The upper heat sink and the lower heat sink may each include a plurality of cooling portions. The cooling portions of the upper heat sink may be disposed on one or both sides of the connecting member at an upper portion of the first battery cell stack and an upper portion of the second battery cell stack. The cooling portions of the lower heat sink may be disposed on one or both sides of the connecting member at a lower portion of the first battery cell stack and a lower portion of the second battery cell stack.

[0032] The battery cells may be stacked in one direction from the first side plate to the second side plate. A compression pad may be interposed between adjacent battery cells, between one of the outermost battery cells and the first side plate, or between another of the outermost battery cells and the second side plate. In an End of Life (EOL) state, a deformation rate in a direction in which the battery cells are stacked may be 12% or less, and a surface pressure applied to the battery cells may be 0.9 MPa or less.

[0033] A module stiffness curve of the battery module is calculated with a slope (MPa / %) in the range of 0.00417 or more and 0.225 or less, and the module stiffness curve of the battery module may correspond to the relationship between the deformation rate of the first side plate and the second side plate and the surface pressure applied to the first side plate and the second side plate.

[0034] A module stiffness curve of the battery module may be derived by reflecting the degree to which the compression pads are compressed with respect to the surface pressure applied to the compression pads and the number of the compression pads in the frame stiffness curve of the first side plate and the second side plate.

[0035] A device according to an embodiment of the present invention may include at least one battery module. Effect of the Invention

[0036] According to the embodiments of the present invention, it is possible to provide a battery pack having a simplified module structure, which improves the energy density per weight and enables weight reduction, and a device including the battery pack.

[0037] In addition, in accordance with the simplified module structure, upper and lower heat sinks can be arranged in the limited upper and lower spaces to improve cooling performance.

[0038] The effects of the present invention are not limited to those mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description of the claims. [Brief description of the drawings]

[0039] [Figure 1] 1 is a perspective view showing a battery module included in a battery pack according to an embodiment of the present invention; [Diagram 2] FIG. 2 is an exploded perspective view of the battery module of FIG. [Diagram 3] 3 is a side view showing one of the battery cells included in the battery module of FIG. 2. [Figure 4] 3 is a perspective view showing a side plate included in the battery module of FIG. 2. [Diagram 5] 2 is a perspective view showing a battery module, a thermal resin layer, an upper heat sink, and a lower heat sink included in a battery pack according to an embodiment of the present invention. FIG. [Figure 6] 6 is a cross-sectional view that illustrates a cross section taken along the line AA' in FIG. 5. [Figure 7] FIG. 2 is a perspective view of an upper heat sink according to an embodiment of the present invention. [Figure 8] 1 is a plan view showing a battery pack according to an embodiment of the present invention; [Figure 9] 1 is a perspective view showing a battery pack according to an embodiment of the present invention; [Figure 10] 4 is a partial perspective view showing a method for fixing a battery module to a pack tray in the battery pack according to the present embodiment. FIG. [Figure 11] FIG. 4 is a perspective view showing a battery module according to another embodiment of the present invention. [Figure 12] FIG. 12 is an exploded perspective view of the battery module of FIG. [Figure 13] FIG. 12 is an exploded perspective view of the battery module of FIG. [Figure 14] 11 is a perspective view illustrating a battery module having a heat sink disposed thereon according to another embodiment of the present invention; FIG. [Figure 15] FIG. 15 is an exploded perspective view of the battery module of FIG. [Figure 16] FIG. 4 is a perspective view showing a battery module according to another embodiment of the present invention. [Figure 17] 4 is a graph showing a module stiffness curve and a PD curve of a battery cell stack for a battery module according to an embodiment of the present invention. [Figure 18] 4 is a graph showing a module stiffness curve and a PD curve of a battery cell stack for a battery module according to an embodiment of the present invention. [Figure 19]4 is a graph showing a module stiffness curve and a PD curve of a battery cell stack for a battery module according to an embodiment of the present invention. [Figure 20] 4 is a graph showing a range of module stiffness curves of a battery module according to an embodiment of the present invention. [Figure 21] 1 is a graph showing a PD curve for a single battery cell. [Figure 22] 1 is a graph showing a PD curve for a single battery cell and a PD curve for a battery cell stack. [Figure 23] 4 is a graph showing module stiffness curves for the first to fourth embodiments according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0040] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention may, however, be embodied in various different forms and should not be construed as being limited to the embodiments set forth herein.

[0041] In order to clearly describe the present invention, parts that are not relevant to the description will be omitted, and the same reference numerals will be used throughout the specification to refer to the same or similar components.

[0042] In addition, the size and thickness of each component shown in the drawings are arbitrarily shown for convenience of explanation, and the present invention is not necessarily limited to those shown. In the drawings, thicknesses are exaggerated to clearly express multiple layers and regions. In the drawings, thicknesses of some layers and regions are exaggerated for convenience of explanation.

[0043] In addition, when a part such as a layer, film, region, or plate is said to be "on" or "above" another part, this includes not only the case where it is "directly above" the other part, but also the case where there is another part in between. Conversely, when a part is said to be "directly above" another part, it means that there is no other part in between. In addition, being "on" or "above" a reference part means being located above or below the reference part, and does not necessarily mean being located "on" or "above" the opposite direction of gravity.

[0044] Also, throughout the specification, when a part "comprises" a certain element, this means that it may further include other elements, but not excluding other elements, unless specifically stated to the contrary.

[0045] Also, throughout the specification, "on a plane" means when the subject part is viewed from above, and "on a cross section" means when the subject part is cut vertically and viewed from the side.

[0046] Fig. 1 is a perspective view showing a battery module included in a battery pack according to an embodiment of the present invention, Fig. 2 is an exploded perspective view of the battery module of Fig. 1, Fig. 3 is a side view showing one of the battery cells included in the battery module of Fig. 2.

[0047] 1 to 3, a battery pack according to an embodiment of the present invention includes a battery module 100, a pack tray for accommodating the battery module, and a heat sink including at least one cooling section through which a refrigerant flows. The heat sink includes at least one of an upper heat sink located on the upper part of the battery module and a lower heat sink located on the lower part of the battery module. The pack tray will be described later with reference to FIGS. 8 and 9, and the upper heat sink and the lower heat sink will be described later with reference to FIGS. 5 to 7.

[0048] 1 to 3, the battery module 100 included in the battery pack includes a battery cell stack 120 in which a plurality of battery cells 110 are stacked, a first side plate 210 and a second side plate 220 located on both sides of the battery cell stack 120, and connecting members 600 disposed on the top and bottom of the battery cell stack 120 to connect the first side plate 210 and the second side plate 220.

[0049] First, the battery cell 110 may be a pouch-type battery cell. Such a pouch-type battery cell may be formed by accommodating an electrode assembly in a pouch case of a laminate sheet including a resin layer and a metal layer, and then bonding the outer periphery of the pouch case. Such a battery cell 110 may be formed in a rectangular sheet structure. Specifically, the battery cell 110 according to the present embodiment has a structure in which two electrode leads 111 and 112 face each other and protrude from one end 114a and the other end 114b of a battery body 113, respectively. The battery cell 110 may be manufactured by bonding one end 114a and the other end 114b of the battery case 114 and one side 114c connecting them in a state in which an electrode assembly (not shown) is accommodated in the battery case 114. In other words, the battery cell 110 according to an embodiment of the present invention has a total of three sealing parts, which are sealed by a method such as fusion, and the remaining other side is formed of a connecting part 115.

[0050] However, the battery cell 110 described above is an exemplary structure, and it goes without saying that a unidirectional battery cell in which two electrode leads protrude in the same direction is also possible.

[0051] Such a battery cell 110 is configured in plurality, and the plurality of battery cells 110 are stacked so as to be electrically connected to each other to form a battery cell stack 120. In particular, as shown in FIG. 2, the plurality of battery cells 110 may be stacked along a direction parallel to the y-axis. The battery case 114 is generally formed in a laminate structure of a resin layer / metal foil film layer / resin layer. For example, if the surface of the battery case is formed of an O(oriented)-nylon layer, it tends to easily slip due to external impact when a large number of battery cells are stacked to form a medium- to large-sized battery module. Therefore, in order to prevent this and maintain a stable stacked structure of the battery cells, the battery cell stack 120 may be formed by attaching an adhesive member such as a pressure-sensitive adhesive such as double-sided tape or a chemical adhesive that bonds by a chemical reaction when bonded to the surface of the battery case.

[0052] FIG. 4 is a perspective view showing a first side plate included in the battery module of FIG.

[0053] 2 and 4, the first side plate 210 and the second side plate 220 are respectively located on both sides of the battery cell stack 120 to support the battery cell stack 120. More specifically, the first side plate 210 and the second side plate 220 may be respectively located on both sides in a direction in which the plurality of battery cells 110 are stacked, i.e., a direction parallel to the y-axis in FIG. 2. Although only the first side plate 210 is shown in FIG. 4, the first side plate 210 and the second side plate 220 may be configured to be identical to each other but symmetrical.

[0054] Meanwhile, the battery module 100 according to the present embodiment includes connection members 600 located on the upper and lower sides of the battery cell stack 120, respectively, for connecting the first side plate 210 and the second side plate 220 together.

[0055] The battery module 100 according to the present embodiment does not have a configuration in which the battery cell stack 120 is housed and sealed in a module housing, but has a configuration in which a first side plate 210 and a second side plate 220 are arranged on both sides of the battery cell stack 120, and the first side plate 210 and the second side plate 220 are fixed by a connecting member 600. That is, the battery module 100 according to the present embodiment has a module housing structure that is simpler than the conventional one, and is directly attached to a battery pack without a sealed module housing. The manner in which it is attached to a battery pack will be described later with reference to Figs. 8 and 9. Therefore, in the present embodiment, the module housing structure is omitted to improve space utilization in the battery pack unit described later, and it is possible to improve the overall energy density and reduce weight.

[0056] The connecting member 600 according to the present embodiment may be a metal band-type member, more specifically, the connecting member 600 may be a band-type member including an elastic metal material.

[0057] The connecting member 600 may be provided in a plurality of locations or alone on at least one of the upper and lower sides of the battery cell stack 120. As an example, a plurality of connecting members 600 may be provided on at least one of the upper and lower sides of the battery cell stack 120. FIG. 2 shows that a plurality of connecting members 600 are provided on both the upper and lower sides of the battery cell stack 120. Such connecting members 600 may be spaced apart from each other at regular intervals and located on the upper and lower sides of the battery cell stack 120, respectively. As an example, FIG. 2 shows that three connecting members 600 are disposed on each of the upper and lower sides of the battery cell stack 120.

[0058] As described above, the connecting member 600 is a member that connects the first side plate 210 and the second side plate 220, and therefore may have a shape that is continuous in the direction from the first side plate 210 to the second side plate 220, i.e., along the stacking direction of the battery cells 110. In other words, the connecting member 600 extends along a direction parallel to the y-axis direction, with one end connected to the first side plate 210 and the other end connected to the second side plate 220. Such a connecting member 600 may be fixed to the first side plate 210 and the second side plate 220 by a welding method.

[0059] Although not specifically shown, in another embodiment of the present invention, the connecting member may be a long bolt member fastened to the first side plate 210 and the second side plate 220. That is, the connecting member may be fastened to the first side plate 210 and the second side plate 220 by bolt connection without welding.

[0060] Meanwhile, the battery module 100 according to this embodiment may further include a first end plate 310 and a second end plate 320 located on one and the other sides, respectively, of the battery cell stack 120; a first bus bar frame 410 located between the battery cell stack 120 and the first end plate 310; and a second bus bar frame 420 located between the battery cell stack 120 and the second end plate 320.

[0061] More specifically, the first busbar frame 410 and the first end plate 310 may be positioned in order on one side in the direction in which one electrode lead (111, see FIG. 3) of the battery cell 110 protrudes (x-axis direction), and the second busbar frame 420 and the second end plate 320 may be positioned in order on the other side in the direction in which the other electrode lead (112, see FIG. 3) of the battery cell 110 protrudes (-x-axis direction).

[0062] The first bus bar frame 410 and the second bus bar frame 420 may be arranged to cover the front and rear surfaces, respectively, of the battery cell stack that correspond to the directions in which the electrode leads 111, 112 protrude (the x-axis direction and the -x-axis direction).

[0063] The first end plate 310 and the second end plate 320 may be arranged to cover one surface of the first bus bar frame 410 and one surface of the second bus bar frame 420, respectively. The first end plate 310 and the second end plate 320 may be plastic insulating covers having electrical insulation, and can protect other electrical components, including the bus bar 500 and the electrode leads 111, 112, located on the first bus bar frame 410 and the second bus bar frame 420, from the outside while preventing a possibility of a short circuit with the outside. Meanwhile, there is no particular limitation on the method of connecting the first end plate 310 and the second end plate 320 to the first side plate 210 and the second side plate 220, and for example, a mechanical connecting method or a bolt connection may be applied.

[0064] Meanwhile, in another embodiment of the present invention, the first end plate 310 and the second end plate 320 may have high rigidity by including a metal material such as aluminum. In this case, however, it is preferable to add separate insulating covers between the first end plate 310 and the first bus bar frame 410 and between the second end plate 320 and the second bus bar frame 420.

[0065] The battery module 100 according to this embodiment may further include a bus bar 500 attached to the first bus bar frame 410 and the second bus bar frame 420. Although not shown, the second bus bar frame 420 and the bus bar 500 attached thereto may have a similar structure to the first bus bar frame 410 shown in FIG.

[0066] The electrode leads 111 and 112 of the battery cell 110 may pass through a lead slit formed in the first bus bar frame 410 or the second bus bar frame 420, and then bend to be connected to the bus bar 500. More specifically, any one of the electrode leads 111 may pass through a lead slit of the first bus bar frame 410 and then be connected to the bus bar 500, and the other electrode lead 112 may pass through a lead slit of the second bus bar frame 420 and then be connected to the bus bar 500. There is no particular limitation on the manner of connection between the electrode leads 111 and 112 and the bus bar 500, but as an example, welding may be performed.

[0067] In this manner, the battery cells 110 constituting the battery cell stack 120 may be connected in series or parallel to each other.

[0068] Meanwhile, although not specifically shown, a terminal bus bar for connecting external power to the battery module 100 and a module connector for transmitting sensing information of voltage and temperature are attached to the first bus bar frame 410 or the second bus bar frame 420.

[0069] The first side plate 210 and the second side plate 220 according to the present embodiment may be disposed to cover the side surfaces of the first bus bar frame 410 and the second bus bar frame 420 .

[0070] 2, the connecting members 600 may be located on the upper or lower side of the battery cell stack 120. A heat sink may be disposed on one side of the connecting members 600. When a plurality of connecting members 600 are provided on at least one of the upper and lower sides of the battery cell stack 120, a heat sink may be disposed in a space between the spaced connecting members 600.

[0071] The above-mentioned structure has an advantage that the cooling member for each module and the cooling member for each pack can be integrated to provide only one cooling member. That is, the cooling path of the battery module 100 inside the battery pack can be integrated and shortened, thereby achieving the effect of reducing weight and costs. Hereinafter, the upper heat sink and the lower heat sink located on one side of the connecting member 600 will be described in detail with reference to Figs. 5 to 7.

[0072] Fig. 5 is a perspective view showing a battery module, a thermal resin layer, an upper heat sink, and a lower heat sink included in a battery pack according to an embodiment of the present invention. Fig. 6 is a cross-sectional view showing a cross section taken along the line A-A' in Fig. 5. Fig. 7 is a perspective view showing an upper heat sink according to an embodiment of the present invention.

[0073] 2, 5, 6 and 7, the battery pack according to the present embodiment includes heat sinks 700A and 700B including at least one cooling unit 710 through which a refrigerant flows, as described above, and the heat sinks 700A and 700B include at least one of an upper heat sink 700A located on the upper part of the battery module 100 or a lower heat sink 700B located on the lower part of the battery module 100. That is, although an embodiment including both the upper heat sink 700A and the lower heat sink 700B is shown in the drawings, both a battery pack having only the upper heat sink 700A and a battery pack having only the lower heat sink 700B are within the scope of the present invention. Hereinafter, the embodiment including both the upper heat sink 700A and the lower heat sink 700B will be described as a reference, but the structural details thereof can also be applied to an embodiment having only the upper heat sink 700A and an embodiment having only the lower heat sink 700B.

[0074] The upper heat sink 700A and the lower heat sink 700B may each include at least one cooling unit 710 through which a refrigerant flows. The cooling unit 710 of the upper heat sink 700A is located on one side of the connecting member 600 at the upper part of the battery module 100, and the cooling unit 710 of the lower heat sink 700B is located on one side of the connecting member 600 at the lower part of the battery module 100.

[0075] Specifically, as described above, the plurality of connecting members 600 may be provided at least one of the upper side or the lower side of the battery cell stack 120. More specifically, the connecting members 600 may be located at least one of the upper side or the lower side of the battery cell stack 120, spaced apart from each other along a direction perpendicular to the stacking direction in which the battery cells 110 are stacked, and the cooling portion 710 of the upper heat sink 700A and the cooling portion 710 of the lower heat sink 700B may be disposed in a space between the connecting members 600 spaced apart from each other. The cooling portion 710 may be a tube member having an internal space S formed therein, and the internal space S may be a space through which a refrigerant flows. The refrigerant may be cooling water, and the upper heat sink 700A and the lower heat sink 700B according to the present embodiment may be water-cooled cooling structures.

[0076] Meanwhile, the battery module 100 according to the present embodiment may further include a thermal resin layer (900) located between the cooling unit 710 and the battery cell stack 120. Specifically, the thermal resin layer 900 may include at least one of an upper thermal resin layer 900A located between the cooling unit 710 of the upper heat sink 700A and the battery cell stack 120, and a lower thermal resin layer 900B located between the cooling unit 710 of the lower heat sink 700B and the battery cell stack 120.

[0077] The thermal resin layer 900 may be formed by hardening a thermal resin that is applied or injected. The thermal resin may include a thermally conductive adhesive material, and more specifically, may include at least one of a silicone material, a urethane material, and an acrylic material. The thermal resin is in a liquid state when applied, and hardens after application to fix one or more battery cells 110 that constitute the battery cell stack 120. In addition, the thermal resin has excellent thermal conductivity, and can quickly transfer heat generated in the battery cells 110 to the upper heat sink 700A and the lower heat sink 700B.

[0078] In summary, the battery module according to the present embodiment has a module housing structure that is simpler than the conventional one, and includes a first side plate 210, a second side plate 220, and a connecting member 600 that connects them, with an upper heat sink 700A and a lower heat sink 700B disposed in the space on one side of the connecting member 600. Furthermore, a thermal resin layer 900 can be disposed in an area adjacent to the upper heat sink 700A and the lower heat sink 700B.

[0079] With the above-mentioned structure, it is possible to minimize space loss in the height direction from the viewpoint of the battery module 100 and the battery pack including the same. Instead of using a separate module housing structure, the adjacent space on one side of the connecting member 600 connecting the first side plate 210 and the second side plate 220 is used as a space in which a heat sink and a thermal resin layer can be positioned, thereby reducing the height of the battery module. This leads to improved energy density and weight reduction of the battery pack including the battery module.

[0080] In addition, since the heat sink and thermal resin layer are not disposed on the outside of a separate module housing, but are positioned adjacent to the upper and lower parts of the battery cell stack 120 on one side of the connecting member 600, the heat transfer path can be simplified and cooling performance can be improved.

[0081] In addition, in an embodiment including both an upper heat sink 700A and a lower heat sink 700B, an upper heat sink 700A and a lower heat sink 700B are provided at the upper and lower parts of the battery module, respectively, thereby forming dual cooling paths in both the upward and downward directions, thereby maximizing cooling performance.

[0082] 6 and 7, in the upper heat sink 700A or the lower heat sink 700B, the cooling unit 710 may include a first cooling unit 711 and a second cooling unit 712 extending in one direction. In addition, each of the upper heat sink 700A and the lower heat sink 700B may further include an inlet unit 720 connected to the first cooling unit 711 to receive the refrigerant, an outlet unit 730 connected to the second cooling unit 712 to discharge the refrigerant, and a connection unit 740 connecting the first cooling unit 711 and the second cooling unit 712.

[0083] At this time, the refrigerant flows along the inlet portion 720, the first cooling portion 711, the connection portion 740, the second cooling portion 712, and the outlet portion 730, forming a circulation structure.

[0084] Hereinafter, the arrangement of the battery modules 100 and the relationship with the heat sink in the battery pack 1000 according to an embodiment of the present invention will be described in detail.

[0085] 8 is a plan view showing a battery pack according to one embodiment of the present invention, specifically, a plane seen along the -z axis direction on the xy plane with respect to a battery pack 1000 in which battery modules 100 are arranged on a pack tray 1100.

[0086] 6 to 8, the battery pack 1000 according to the present embodiment includes the battery module 100, the pack tray 1100 for accommodating the battery module 100, and the heat sinks 700A and 700B including at least one cooling portion through which a refrigerant flows, as described above. Although only the upper heat sink 700A is shown in FIG. 8, the lower heat sink may have the same or similar shape as the upper heat sink 700A shown below the battery module 100.

[0087] A plurality of battery modules 100 may be arranged on the pack tray 1100, and at least two battery modules 100 may be arranged along a stacking direction in which the battery cells are stacked. The stacking direction in which the battery cells are stacked is parallel to the y-axis in the drawing.

[0088] The cooling unit 710 may pass through one side of the connecting member 600 of any one battery module 100 and one side of the connecting member 600 of another battery module 100 adjacent to the any one battery module 100 .

[0089] More specifically, the cooling unit 710 may pass between the connecting members 600 of any one battery module 100 and between the connecting members 600 of another battery module 100 adjacent to the any one battery module 100. That is, at least two battery modules 100 may share the cooling unit 710.

[0090] As described above, the cooling unit 710 may include the first cooling unit 711 and the second cooling unit 712 extending in one direction, and the refrigerant C may flow along the inlet unit 720, the first cooling unit 711, the connection unit 740, the second cooling unit 712, and the outlet unit 730 to form a circulation structure. At this time, the one direction in which the first cooling unit 711 and the second cooling unit 712 extend may be parallel to the stacking direction in which the battery cells are stacked. At least two battery modules 100 may share the first cooling unit 711 and the second cooling unit 712.

[0091] In this case, based on the battery module 100, the inlet 720 and the outlet 730 may be located on the same side, and the connection part 740 may be located on the opposite side of the inlet 720 and the outlet 730. That is, in forming a refrigerant circulation structure, the first cooling part 711, the second cooling part 712, and the connection part 740 connecting the first cooling part 711 and the second cooling part 712 are provided, and the inlet 720 and the outlet 730 may be located together in one area A1 of the battery module 100.

[0092] Therefore, a refrigerant circulation system (not shown) connected to the inlet portion 720 and the outlet portion 730 only needs to be installed on one side of the battery pack 1000, so that the space inside the battery pack 1000 can be utilized efficiently and the area where there is a risk of refrigerant leakage can be limited to the vicinity of one area A1.

[0093] 5 and 6, there is no limit to the number of first cooling units 711 and second cooling units 712 arranged in one battery module 100. As an example, three connecting members 600 may be located at the upper and lower parts of the battery cell stack 120, and two first cooling units 711 and two second cooling units 712 may be arranged separately between the three connecting members 600.

[0094] Hereinafter, a manner in which the battery module according to the present embodiment is fixed to the pack case will be described in detail.

[0095] Fig. 9 is a perspective view showing a battery pack according to an embodiment of the present invention. Fig. 10 is a partial perspective view showing a method of fixing a battery module to a pack tray in a battery pack according to the present embodiment. For convenience of explanation, an upper heat sink and an upper thermal resin layer are omitted in Fig. 9. That is, an embodiment in which only a lower heat sink is disposed as shown in the figure can be applied, and another embodiment can be applied in which an upper heat sink and an upper thermal resin layer are added to Fig. 9.

[0096] 4, 9 and 10, when the battery module 100 according to the present embodiment is housed in the pack tray 1100, the first side plate 210 and the second side plate 220 are fixed to the pack tray 1100. As shown in FIG.

[0097] First, the first side plate 210 and the second side plate 220 according to the present embodiment may each include a support portion 200S that supports the outermost battery cell of the battery cell stack 120, and a fixing portion 200F that protrudes in a direction perpendicular to one surface of the support portion 200S. Both the first side plate 210 and the second side plate 220 may have the fixing portion 200F formed on a surface opposite to the surface in which the battery cell stack is located.

[0098] The fixing portion 200F may have a through hole 200FH for mounting and fixing. There is no particular limit to the number of the fixing portion 200F, and the fixing portion 200F may be provided in one or more. Fig. 4 shows a case where a plurality of the fixing portions 200F are arranged at a predetermined interval.

[0099] The pack tray 1100 is a structure having an internal space in which one or more battery modules 100 can be stored. One or more battery modules 100 are disposed on a bottom 1100F of the pack tray 1100. Although not specifically shown, a pack cover may be disposed to cover the open top of the pack tray 1100.

[0100] At this time, in preparation for external vibrations and impacts, it is necessary to attach and fix the battery module 100 to the pack tray 1100. According to this embodiment, the first side plate 210 and the second side plate 220 of the battery module 100 are fixed to the pack tray 1100.

[0101] Specifically, as described above, the first side plate 210 and the second side plate 220 support the outermost battery cell of the battery cell stack, and may include a support portion 200S arranged in a shape perpendicular to the bottom portion 1100F of the pack tray 1100, and a fixing portion 200F protruding in a direction perpendicular to one surface of the support portion 200S. At this time, the fixing portion 200F may be fixed to the pack tray 1100.

[0102] More specifically, the pack tray 1100 according to this embodiment may further include a mounting beam 1200 disposed on an upper surface of the bottom portion 1100F of the pack tray 1100, and the fixed portion 200F may be fixed to the mounting beam 1200.

[0103] The mounting beam 1200 has a shape extending in one direction on the upper surface of the bottom 1100F of the pack tray 1100. Although not specifically shown, when a plurality of battery modules 100 are arranged, the mounting beam 1200 may be located between the battery modules 100. Such a mounting beam 1200 may fix the battery modules 100 and cushion shocks, etc. transmitted to the battery modules 100 from external shocks, etc.

[0104] 10, the fixing part 200F may have a through hole 200FH for mounting and fixing. Meanwhile, in the height direction, the fixing part 200F may be located higher than the height of the mounting beam 1200. Here, the height direction means a direction perpendicular to one surface of the bottom part 1100F of the pack tray 1100.

[0105] The fixing part 200F may be fixed to the upper surface of the mounting beam 1200, and a bolt connection may be performed as shown in Fig. 10. That is, a mounting hole 1200H having an internal thread may be formed in the upper surface of the mounting beam 1200, and a bolt-shaped fastening member 1300 may be inserted into and fastened to the mounting hole 1200H after passing through a through hole 200FH of the fixing part 200F.

[0106] As described above, the battery module 100 according to the present embodiment can be fixed to the pack tray 1100 by the first side plate 210 and the second side plate 220 to form the battery pack 1000.

[0107] Meanwhile, during repeated charging and discharging of the battery cells 110, the electrolyte therein may decompose, generating gas and causing the battery cells 110 to swell, i.e., a swelling phenomenon may occur. If the swelling of the battery cells 110 cannot be controlled, it may cause structural deformation of the battery module 100 in which multiple battery cells 110 are stacked, and may also adversely affect the durability and performance of the battery module 100.

[0108] In particular, pure Si cells, solid-state batteries, and high SiO content cells are recently used as battery cells to manufacture high-capacity battery modules and battery packs, but the degree of swelling is greater in the case of these cells. That is, in order to manufacture high-capacity battery modules and battery packs, it is essential to effectively control the swelling of the battery cells 110 inside the battery module or battery pack. Referring again to FIG. 2, since the pouch-type battery cell 110 usually has a large degree of swelling in the thickness direction, the structures directly related to swelling control are the first side plate 210 and the second side plate 220 arranged on both sides of the battery cell stack 120.

[0109] The battery module 100 according to the present embodiment does not have a module housing that integrally surrounds the battery cell stack, but has a simplified housing structure using a first side plate 210, a second side plate 220, and a connecting member 600 that connects them. Therefore, it may be difficult to provide the lateral rigidity and durability required to control the swelling of the battery cells 110.

[0110] Therefore, in the battery pack 1000 according to the present embodiment, the battery module 100 having a simplified housing structure is arranged, and the first side plate 210 and the second side plate 220 are directly coupled and fixed to the mounting beam 1200 on the pack tray 1100, and the mounting beam 1200 is designed to support the first side plate 210 and the second side plate 220 laterally to control swelling.

[0111] That is, the mounting and fixing is performed by the first side plate 210 and the second side plate 220, and at the same time, the mounting beam 1200 can complement the rigidity and durability of the battery module 100 for swelling control.

[0112] In summary, the first side plate 210 and the second side plate 220 according to the present embodiment can function as a mounting and fixing member by being directly fixed to the mounting beam 1200 on the pack tray 1100 in the battery module 100 having a simplified housing structure, and can also function as a stiffness supplement for swelling control of the battery module 100. In addition, the upper heat sink 700A and the lower heat sink 700B are disposed in the space on one side of the connecting member 600 connecting the first side plate 210 and the second side plate 220, thereby minimizing the increase in height and arranging the cooling structure. The aim is to increase the energy density of the battery pack by reducing the space loss in the height direction.

[0113] Meanwhile, referring again to Fig. 2, the battery module 100 according to the present embodiment may further include an insulating sheet 800 positioned between the battery cell stack 120 and the connecting member 600 positioned on the upper side of the battery cell stack 120. The insulating sheet 800 is an electrically insulating thin sheet, and may be disposed to cover the entire upper surface of the battery cell stack 120 to ensure electrical insulation for the upper side of the battery cell stack 120. Such an insulating sheet 800 may be an insulating film or insulating tape, and may have a thickness of 0.1 mm or less.

[0114] In other embodiments of the present invention, it is also possible that no insulating sheet is disposed between the battery cell stack 120 and the connecting members 600. That is, an embodiment is also possible in which the upper surface of the battery cell stack 120 is exposed to the outside through the connecting members 600 or between the connecting members 600 and the first end plate 310 and the second end plate 320, and is in direct contact with the upper thermal resin layer 900A. Similarly, the battery cell stack 120 may also be in direct contact with the lower thermal resin layer 900B.

[0115] Hereinafter, a battery module and a battery pack including the same according to another embodiment of the present invention will be described in detail with reference to Figs. 11 to 15. However, for the sake of brevity, parts that overlap with the contents of the above-described embodiment will be omitted.

[0116] Fig. 11 is a perspective view showing a battery module according to another embodiment of the present invention. Figs. 12 and 13 are exploded perspective views of the battery module of Fig. 11. Specifically, Fig. 12 illustrates a state in which the battery cell stack 120, the first side plate 210 and the second side plate 220, and the first end plate 310 and the second end plate 320 are separated, and Fig. 13 illustrates a state in which the first bus bar frame 410, the second bus bar frame 420, and the connecting member 600 are separated in addition to Fig. 12.

[0117] 11 to 13, a battery module 100t according to another embodiment of the present invention includes a battery cell stack 120 in which a plurality of battery cells 110 are stacked, a first side plate 210 and a second side plate 220 located on both sides of the battery cell stack 120, and a connecting member 600 disposed on an upper and lower part of the battery cell stack 120 to connect the first side plate 210 and the second side plate 220. The connecting member 600 may be provided in multiple or alone on the upper and lower parts of the battery cell stack 120.

[0118] At this time, the battery cell stack 120 according to the present embodiment may include a first battery cell stack 120a and a second battery cell stack 120b. The first battery cell stack 120a and the second battery cell stack 120b may be arranged to be spaced apart along a direction perpendicular to a stacking direction in which the battery cells 110 are stacked. Each of the first battery cell stack 120a and the second battery cell stack 120b has the same structure as the battery cell stack described above in that the battery cells 110 are stacked in one direction. That is, the battery cells 110 in the first battery cell stack 120a and the second battery cell stack 120b may be stacked along a direction parallel to the y-axis, and the first battery cell stack 120a and the second battery cell stack 120b may be arranged to be spaced apart along a direction parallel to the x-axis.

[0119] In this embodiment, a first battery cell stack 120a and a second battery cell stack 120b are arranged in one battery module 100t, which corresponds to a kind of twin model battery module.

[0120] The first side plate 210 may extend to cover all of one side of the first battery cell stack 120a and one side of the second battery cell stack 120b, and the second side plate 220 may extend to cover all of the other side of the first battery cell stack 120a and the other side of the second battery cell stack 120b.

[0121] The first side plate 210 and the second side plate 220 may be positioned to cover both side surfaces of the first battery cell stack 120a and the second battery cell stack 120b in the direction in which the battery cells 110 are stacked.

[0122] In addition, the first side plate 210 and the second side plate 220 may include a support portion 200S that supports the outermost battery cell of the battery cell stack 120 and a fixing portion 200F that protrudes in a direction perpendicular to one surface of the support portion 200S. In addition, a connecting member 600 may connect the first side plate 210 and the second side plate 220. As an example, in a state where a plurality of connecting members 600 are positioned on the upper and lower sides of the first battery cell stack 120a and the second battery cell stack 120b, one end of the connecting member 600 may be connected to the first side plate 210 and the other end of the connecting member 600 may be connected to the second side plate 220. Description of this embodiment will be omitted as it overlaps with the description of the previous embodiment.

[0123] Meanwhile, the battery module 100t according to this embodiment may further include a first end plate 310 located on one side of the first battery cell stack 120a and a second end plate 320 located on one side of the second battery cell stack 120b. The first end plate 310 and the second end plate 320 may be located on opposite sides of the first battery cell stack 120a and the second battery cell stack 120b.

[0124] The battery module 100t may further include an insulating plate 330 located between the first battery cell stack 120a and the second battery cell stack 120b. The first end plate 310, the second end plate 320, and the insulating plate 330 may be plastic insulating covers having electrical insulation. Meanwhile, the manner of connection between the first end plate 310, the second end plate 320, the insulating plate 330, and the first side plate 210, the second side plate 220 is not particularly limited, and as an example, a mechanical connection method or bolt connection may be applied.

[0125] The battery module 100t may include a first busbar frame 410 positioned between the first battery cell stack 120a and the first end plate 310, and a second busbar frame 420 positioned between the first battery cell stack 120a and the insulating plate 330. The battery module 100t may also include a third busbar frame 430 positioned between the second battery cell stack 120b and the insulating plate 330, and a fourth busbar frame 440 positioned between the second battery cell stack 120b and the second end plate 320.

[0126] The first to fourth busbar frames 410, 420, 430, and 440 may have the same or similar structures as the busbar frames described above. As an example, a busbar 500 is attached to the first to fourth busbar frames 410, 420, 430, and 440. The electrode leads 111 and 112 of the battery cells 110 may pass through lead slits formed in the first to fourth busbar frames 410, 420, 430, and 440 and then bend to be connected to the busbar 500. Detailed description thereof will be omitted as it is the same as that described above.

[0127] The insulating plate 330 may be located between the second busbar frame 420 and the third busbar frame 430. One side of the insulating plate 330 may cover the second busbar frame 420, and the other side of the insulating plate 330 may cover the third busbar frame 430. Since the insulating plate 330 includes an electrically insulating material, it is possible to prevent a short circuit from occurring between the electrical components attached to the second busbar frame 420 and the third busbar frame 430, respectively.

[0128] The first side plate 210 and the second side plate 220 according to this embodiment may be disposed to cover the side surfaces of the first bus bar frame 410 and the fourth bus bar frame 440 .

[0129] In order to achieve the same battery capacity between the battery module 100t shown in Figures 11 to 13 and the battery module 100 shown in Figures 1 and 2, one battery module 100t must be compared with two battery modules 100. This is because the battery module 100t shown in Figures 11 to 13 includes a first battery cell stack 120a and a second battery cell stack 120b.

[0130] In one battery module 100t, a first end plate 310, a second end plate 320, and an insulating plate 330 are arranged along a direction perpendicular to the stacking direction of the battery cells 110, i.e., a direction parallel to the x-axis. That is, a total of three components are arranged. In contrast, in two battery modules 100, two first end plates 310 and two second end plates 320 are arranged. That is, a total of four components are arranged.

[0131] Therefore, the battery module 100t according to the present embodiment has advantages in that the space utilization rate in the longitudinal direction of the module is increased and the number of parts is reduced, compared to the battery module 100 described above.

[0132] Also, in the case of the first side plate 210 and the second side plate 220, while only one battery module 100t is required, two battery modules 100 are arranged, so two first side plates 210 and two second side plates 220 are required, which has the advantage of reducing the number of parts.

[0133] Fig. 14 is a perspective view showing a state in which a heat sink is arranged on a battery module according to another embodiment of the present invention. Specifically, Fig. 14 shows a state in which a plurality of battery modules as shown in Figs. 11 to 13 are arranged and a heat sink is arranged on such a battery module. Fig. 15 is an exploded perspective view of the battery module of Fig. 14.

[0134] 13 to 15, the battery pack according to the present embodiment may include a battery module 100t. As described above, the battery module 100t is disposed on a pack tray, but the pack tray is not shown. In this case, the battery pack includes heat sinks 700A and 700B including at least one cooling unit 710 through which a refrigerant flows. The heat sinks 700A and 700B may include at least one of an upper heat sink 700A located on the upper part of the battery module 100t or a lower heat sink 700B located on the lower part of the battery module 100t. Although the drawings show an embodiment including both the upper heat sink 700A and the lower heat sink 700B, both a battery pack having only the upper heat sink 700A disposed thereon and a battery pack having only the lower heat sink 700B disposed thereon correspond to embodiments of the present invention.

[0135] The upper heat sink 700A and the lower heat sink 700B may include a plurality of cooling portions 710. The cooling portions 710 of the upper heat sink 700A may be disposed on one or both sides of the connecting member 600 at the top of the first battery cell stack 120a and the top of the second battery cell stack 120b. The cooling portions 710 of the lower heat sink 700B may be disposed on one or both sides of the connecting member 600 at the bottom of the first battery cell stack 120a and the bottom of the second battery cell stack 120b.

[0136] When a plurality of connecting members 600 are provided, the connecting members 600 may be positioned spaced apart from each other in a direction perpendicular to the stacking direction in which the battery cells 110 are stacked on the upper or lower side of the first battery cell stack 120a and the second battery cell stack 120b, and the cooling portion 710 of the upper heat sink 700A and the cooling portion 710 of the lower heat sink 700B may be disposed in a space between the spaced apart connecting members 600. The cooling portion 710 may be a tube member having an internal space S formed therein, and the internal space S may be a space through which a refrigerant flows.

[0137] The battery module 100t according to the present embodiment may further include a thermal resin layer (900) located between the cooling portion 710 and the battery cell stack 120. Specifically, the thermal resin layer 900 may include at least one of an upper thermal resin layer 900A located between the cooling portion 710 of the upper heat sink 700A and the battery cell stack 120, and a lower thermal resin layer 900B located between the cooling portion 710 of the lower heat sink 700B and the battery cell stack 120.

[0138] As described above, the above-described structure allows the height of the battery module to be reduced by utilizing the space on one side of the connecting member 600 as a space in which the heat sink and the thermal resin layer can be positioned, and also simplifies the heat transfer path to improve the cooling performance.

[0139] Meanwhile, in the upper heat sink 700A or the lower heat sink 700B, the cooling unit 710 may include a first cooling unit 711 and a second cooling unit 712 extending in one direction. Also, each of the upper heat sink 700A and the lower heat sink 700B may further include an inlet unit 720 connected to the first cooling unit 711 to receive the refrigerant, an outlet unit 730 connected to the second cooling unit 712 to discharge the refrigerant, and a connecting unit 740 connecting the first cooling unit 711 and the second cooling unit 712. The refrigerant flows along the inlet unit 720, the first cooling unit 711, the connecting unit 740, the second cooling unit 712, and the outlet unit 730 to form a circulation structure.

[0140] Meanwhile, the battery modules 100t may be configured in a plurality of units, and at least two battery modules 100t may be arranged along a stacking direction in which the battery cells are stacked. The stacking direction in which the battery cells are stacked refers to a direction parallel to the y-axis in the drawings. As an example, Figs. 14 and 15 show three battery modules 100t arranged along the stacking direction in which the battery cells are stacked.

[0141] The cooling unit 710 may pass through one side of the connecting member 600 of any one battery module 100t, and may also pass through one side of the connecting member 600 of another battery module 100t adjacent to the any one battery module 100t. That is, at least two battery modules 100t may share the cooling unit 710. Since the battery module 100t according to the present embodiment has a configuration in which the first battery cell stack and the second battery cell stack are arranged in the longitudinal direction of the module, the cooling unit 710 may be shared between the battery modules 100t arranged along the stacking direction of the battery cells.

[0142] As described above, the cooling unit 710 may include the first cooling unit 711 and the second cooling unit 712 extending along one direction, and the one direction in which the first cooling unit 711 and the second cooling unit 712 extend may be parallel to the stacking direction in which the battery cells are stacked. At least two battery modules 100t may share the first cooling unit 711 and the second cooling unit 712.

[0143] In this case, the inlet 720 and the outlet 730 may be located on the same side of the battery module 100t, and the connection part 740 may be located on the opposite side to the inlet 720 and the outlet 730. As a result, a refrigerant circulation system (not shown) connected to the inlet 720 and the outlet 730 only needs to be provided on one side of the battery pack 1000, so that the space inside the battery pack 1000 can be efficiently utilized and the area where there is a risk of refrigerant leakage can be limited to the vicinity of one area.

[0144] There is no limit to the number of first cooling units 711 and second cooling units 712 arranged in one battery module 100t. In particular, since the battery module 100t has a configuration in which the first battery cell stack and the second battery cell stack are arranged in the longitudinal direction of the module, more first cooling units 711 and second cooling units 712 are required.

[0145] Hereinafter, a battery module according to another embodiment of the present invention will be described in detail with reference to Fig. 16. However, for the sake of brevity, parts that overlap with the above-described embodiment will be omitted.

[0146] FIG. 16 is a perspective view showing a battery module according to another embodiment of the present invention.

[0147] 16, a battery module 100s according to another embodiment of the present invention includes a battery cell stack 120 in which a plurality of battery cells are stacked, and a first side plate 210 and a second side plate (not shown) located on both sides of the battery cell stack 120. The battery cell stack 120, the first side plate 210 and the second side plate (not shown) may have the same or similar structures as those in the above-described embodiment. A detailed description thereof will be omitted as it overlaps with the above description.

[0148] The battery module 100s according to the present embodiment includes a connecting member 600 disposed at the upper and lower parts of the battery cell stack 120 to connect the first side plate 210 and the second side plate (not shown). At this time, the connecting member 600 may be provided separately at the upper and lower parts of the battery cell stack 120. That is, a single connecting member 600 may be located at the upper part of the battery cell stack 120, and a single connecting member may be located at the lower part of the battery cell stack 120. The connecting member 600 may extend along a direction parallel to the y-axis direction, and one end part may be connected to the first side plate 210 and the other end part may be connected to the second side plate (not shown). The connecting member 600 may be fixed to the first side plate 210 and the second side plate (not shown) by a welding method.

[0149] That is, unlike the above-described embodiment in which multiple connecting members were provided on each of the upper and lower parts of the battery cell stack 120, the battery module 100s according to the present embodiment includes connecting members 600 arranged one on each of the upper and lower parts of the battery cell stack 120.

[0150] Although not specifically shown, the heat sinks may be disposed on one or both sides of such a connecting member 600. That is, an upper heat sink may be disposed on one or both sides of the connecting member 600 located on the upper part of the battery cell stack 120, and a lower heat sink may be disposed on one or both sides of the connecting member 600 located on the lower part of the battery cell stack 120.

[0151] More specifically, an upper thermal resin layer 900A may be formed in an area between the connecting member 600 and the first end plate 310 and an area between the connecting member 600 and the second end plate 320 in the upper region of the battery cell stack 120. An upper heat sink (not shown) may be positioned on the upper thermal resin layer 900A.

[0152] Similarly, a lower thermal resin layer 900B may be formed in a region between the connecting member 600 and the first end plate 310 and a region between the connecting member 600 and the second end plate 320 in the lower region of the battery cell stack 120. A lower heat sink (not shown) may be located below the lower thermal resin layer 900B.

[0153] Hereinafter, a design method for the battery module according to the present embodiment will be described with reference to FIGS.

[0154] 17 to 19 are graphs showing module stiffness curves and PD curves of a battery cell stack for a battery module according to one embodiment of the present invention, and Fig. 20 is a graph showing the range of the module stiffness curve of a battery module according to one embodiment of the present invention.

[0155] 2 and 17 to 20, in a battery module 100 according to an embodiment of the present invention, the battery cells 110 may be stacked in one direction from a first side plate 210 to a second side plate 220. In addition, a compression pad may be interposed between adjacent battery cells 110, between one of the outermost battery cells 110 and the first side plate 210, or between another of the outermost battery cells 110 and the second side plate 220.

[0156] At this time, a module stiffness curve C1 caused by the first side plate 210 and the second side plate 220 and a PD (Pressure-Displacement) curve C3 of the battery cell stack 120 showing the swelling characteristics of the battery cell 110 are calculated and fitted to one graph. Then, the swelling behavior of the battery module can be predicted by finding the equilibrium point (intersection point) between the two curves.

[0157] 17 to 19 show intersections (P, P', P") between the module stiffness curves (C1, C1', C") and the PD curve C3 of the battery cell stack. The PD curve C3 of the battery cell stack is a graph showing the relationship between the surface pressure received by the battery cell 110 and the degree of change in thickness of the battery cell 110 caused by swelling of the battery cell 110. The PD curve C3 of the battery cell stack can be measured in an End of Life (EOL) state of the battery cell 110. Here, EOL refers to a state when the ratio of the current capacity of the battery to the initial capacity of the battery reaches a predetermined ratio, and the ratio may be 80%. In other words, EOL refers to a battery state when the capacity of the battery reaches 80% of the initial capacity, which corresponds to a state in which the battery has reached the end of its life or needs to be replaced. Meanwhile, the module rigidity curves (C1, C1', C") are graphs showing the relationship between the degree of change in the width (W) between the first side plate 210 and the second side plate 220 along the direction in which the battery cells 110 are stacked and the load applied to the first side plate 210 and the second side plate 220. The direction in which the battery cells 110 are stacked is the direction from the first side plate 210 to the second side plate 220, and hereinafter the direction in which the battery cells 110 are stacked is referred to as the width direction. In addition, the width (W) of the first side plate 210 and the second side plate 220 means the distance between the first side plate 210 and the second side plate 220 along the width direction. The module rigidity curve C1 and the PD curve C3 of the battery cell stack will be described in detail below.

[0158] In each of the module stiffness curves (C1, C1', C") and the PD curve C3 of the battery cell stack, the X-axis corresponds to the deformation rate, which may be in %, and the Y-axis corresponds to the applied surface pressure, which may be in MPa.

[0159] The intersection point (P, P', P") between the module stiffness curve (C1, C1', C") and the PD curve C3 of the battery cell stack corresponds to the point where the behavior due to swelling of the battery cell stack 120 and the behavior due to deformation of the first side plate 210 and the second side plate 220 reach an equilibrium. In other words, in the case of a battery module in which a battery cell stack 120 exhibiting a particular PD curve C3 in an End of Life (EOL) state is housed in a space formed by the first and second side plates 210 and 220 exhibiting a particular module stiffness curve C1 and the connecting member 600, it can be predicted that the battery module will have a deformation rate and surface pressure corresponding to the intersection (P, P', P") in the EOL state. That is, the battery module is deformed in the width direction by an amount corresponding to the X-axis value of the intersection (P, P', P") in the EOL state, and the battery cells 110, the first side plate 210, and the second side plate 220 are subjected to surface pressure corresponding to the Y-axis value of the intersection (P, P', P")

[0160] 17, it is preferable that the intersection point P is located between the deformation limit point x1 and the pressure limit point y1. The deformation limit point x1 is 12%, and the pressure limit point y1 is 0.9 MPa. That is, it is preferable that the X-axis value of the intersection point P is 12% or less of the deformation limit point x1, and the Y-axis value of the intersection point P is 0.9 MPa or less of the pressure limit point y1. That is, in the EOL state, the battery module according to this embodiment may have a deformation rate of 12% or less in the direction in which the battery cells 110 are stacked, and the surface pressure applied to the battery cells 110 may be 0.9 MPa or less.

[0161] 18, when the Y-axis value of the intersection point P' exceeds the pressure limit point y1, it is predicted that a surface pressure exceeding the pressure limit point y1 is applied to the battery cell 110 and the first and second side plates 210 and 220 of the corresponding battery module in the EOL state. When a pressure exceeding 0.9 MPa of the pressure limit point y1 is applied to the battery cell 110, a problem of deterioration in the life performance of the battery cell 110, such as sudden drop, may occur. In addition, when a pressure exceeding 0.9 MPa of the pressure limit point y1 is applied to the first and second side plates 210 and 220, a surface pressure exceeding the yield strength is applied, and the first and second side plates 210 and 220 may be damaged and deformed.

[0162] As shown in FIG. 19 , when the X-axis value of intersection point P″ exceeds the deformation limit point x1, it is predicted that the battery module will be deformed in the width direction beyond the deformation limit point x1 in the EOL state. This means that excessive change in thickness due to expansion of the battery cell 110 is permitted, which may cause problems such as disconnection between the electrode lead and the tab within the battery cell 110 and cracks in the pouch-type battery case of the battery cell 110. In addition, since the battery module is predicted to be deformed by more than 12% of the deformation limit point x1, the space occupied by the battery module inside the battery pack will increase excessively, which will cause a decrease in the energy density of the battery module and the battery pack.

[0163] 20, in the case of the battery module according to the present embodiment, the module stiffness curve C1 can be calculated in a range of a slope (MPa / %) of 0.00417 or more and 0.225 or less. That is, the module stiffness curve C1 of the battery module according to the present embodiment can be formed in a range between a lower limit module stiffness curve C1b having a slope Sb value of 0.00417 MPa / % and an upper limit module stiffness curve C1a having a slope Sa value of 0.225 MPa / %. Since the intersection P between the module stiffness curve C1 and the PD curve C3 of the battery cell stack is located in a range between the deformation limit point x1 and the pressure limit point y1, it is preferable that the module stiffness curve C1 be calculated in a range of a slope (MPa / %) of 0.00417 or more and 0.225 or less.

[0164] The module stiffness curve C1 will be described in detail below. As described above, the module stiffness curve C1 is a graph showing the relationship between the degree of change in the width between the first side plate 210 and the second side plate 220 along the direction in which the battery cells 110 are stacked and the load applied to the first side plate 210 and the second side plate 220. From the viewpoint of the module stiffness curve C1, the X-axis corresponds to the deformation rate (%) according to the width direction between the first side plate 210 and the second side plate 220. The deformation rate can be calculated based on the width between the first side plate 210 and the second side plate 220 deformed along the width direction with respect to the width between the first side plate 210 and the second side plate 220 before deformation. For example, the deformation rate can be calculated as the ratio of the degree to which the width between the first side plate 210 and the second side plate 220 has been deformed with respect to the width between the first side plate 210 and the second side plate 220 before deformation. From the viewpoint of the module rigidity curve C1, the Y-axis corresponds to the surface pressure (MPa) applied to the first side plate 210 and the second side plate 220 in accordance with the deformation rate of the first side plate 210 and the second side plate 220.

[0165] In order to calculate the module stiffness curve C1, a frame stiffness curve is first calculated. The frame stiffness curve is a graph showing the relationship between the deformation rate of the first side plate 210 and the second side plate 220 and the surface pressure applied to the first side plate 210 and the second side plate 220. Such a frame stiffness curve can be obtained by several actual tests or simulations. For example, an actual force is applied to the first side plate 210 and the second side plate 220 connected to the connecting member 600, and the degree of deformation in the width direction between the first side plate 210 and the second side plate 220 due to the force is measured. The frame stiffness curve can be derived by repeatedly performing the measurement while changing the applied force. The module stiffness curve C1 can be derived by considering the influence of the compression pad on such a frame stiffness curve. Specifically, the degree to which the compression pad is compressed with respect to the surface pressure applied to the compression pad and the number of compression pads are reflected in the frame stiffness curve to finally derive the module stiffness curve C1.

[0166] The PD curve C3 of the battery cell stack is described in detail below. As described above, the PD curve C3 of the battery cell stack is a graph showing the relationship between the surface pressure received by the battery cells 110 and the degree of change in thickness of the battery cells 110 due to swelling. From the perspective of the PD curve C3 of the battery cell stack, the X-axis corresponds to the deformation rate (%) according to the width direction of the battery cell stack 120, and the Y-axis corresponds to the surface pressure MPa applied to the battery cells 110 included in the battery cell stack 120.

[0167] The process of calculating the PD curve C3 of such a battery cell stack will be described in detail below with reference to FIGS. 21 and 22.

[0168] FIG. 21 is a graph showing the PD curve for a single battery cell.

[0169] Referring to FIG. 21, the thickness change amount and surface pressure due to the charge / discharge cycle of a single battery cell 110 can be measured. Specifically, a single battery cell 110 is placed in a fixing jig in which the thickness change is limited, and then the charge / discharge cycle is repeated. Then, a surface pressure value of a0 is measured by a load cell placed in the fixing jig. The measured a0 is represented by P0 on the Y axis. Next, a single battery cell 110 is placed in a variable jig in which the thickness can be changed by a spring or the like, and then the charge / discharge cycle is repeated. Then, a surface pressure value of a1 is measured by a load cell placed in the variable jig, and the thickness increase of the battery cell 110 is measured to calculate the thickness deformation rate of b1. The a1 and b1 are represented by a point P1. The spring constant of the variable jig is changed, and the measurement process is repeated to measure the surface pressure values ​​of a2, a3, and a4 and the deformation rate values ​​of b2, b3, and b4, respectively. Based on these values, coordinate points P2, P3, and P4 can be displayed, and one curve C2 can be derived. The curve C2 derived in this manner corresponds to the PD (Pressure-Displacement) curve of a single battery cell.

[0170] FIG. 22 is a graph showing the PD curve for a single battery cell and the PD curve for a battery cell stack.

[0171] 21 and 22, a PD curve C3 of the battery cell stack 120 can be obtained by reflecting the number of battery cells 110 included in the battery cell stack 120 on the PD curve C2 of a single battery cell obtained by the process described in FIG 21. As the number of battery cells 110 increases, the required surface pressure according to the degree of deformation increases, so the PD curve C3 of the battery cell stack 120 will naturally be located above the PD curve C2 of a single battery cell.

[0172] FIG. 23 is a graph showing module stiffness curves for the first to fourth embodiments according to the present invention.

[0173] 23 shows the module stiffness curves for each of Embodiments 1 to 4. The PD curves for the battery cell stack are not shown, but the equilibrium points (intersections) where the module stiffness curves for each of Embodiments 1 to 4 intersect with the PD curves for each of the battery cell stacks for Embodiments 1 to 4 are shown.

[0174] When the swelling behavior of the battery module predicted by the above-mentioned method is examined, in the EOL state, the battery module of the first embodiment is predicted to be deformed in the width direction by 5.4%, and the internal battery cells, first side plate, and second side plate are predicted to be subjected to a surface pressure of 0.8 MPa. In addition, in the EOL state, the battery module of the second embodiment is predicted to be deformed in the width direction by 6.7%, and the internal battery cells, first side plate, and second side plate are predicted to be subjected to a surface pressure of 0.71 MPa. In addition, in the EOL state, the battery module of the third embodiment is predicted to be deformed in the width direction by 6.1%, and the internal battery cells, first side plate, and second side plate are predicted to be subjected to a surface pressure of 0.29 MPa. Finally, in the EOL state, the battery module of the fourth embodiment is predicted to be deformed in the width direction by 9.3%, and the internal battery cells, first side plate, and second side plate are predicted to be subjected to a surface pressure of 0.44 MPa.

[0175] In all of the battery modules of embodiments 1 to 4, in an EOL (End of Life) state, the deformation rate in the stacking direction of the battery cells is 12% or less, and the surface pressure applied to the battery cells is 0.9 MPa or less. Furthermore, the battery modules of embodiments 1 to 4 have module stiffness curves calculated with a slope (MPa / %) in the range of 0.00417 to 0.225. That is, the module stiffness curves of the battery modules of embodiments 1 to 4 can be formed in a range between a lower limit module stiffness curve C1b with a slope Sb value of 0.00417 MPa / % and an upper limit module stiffness curve C1a with a slope Sa value of 0.225 MPa / %.

[0176] In this embodiment, terms indicating directions such as front, back, left, right, up, and down are used, but these terms are used for convenience of explanation and may change depending on the position of the target object or the position of the observer, etc.

[0177] One or more battery modules according to the present embodiments described above may be installed together with various control and protection systems, such as a Battery Management System (BMS), a Battery Disconnect Unit (BDU), and a cooling system, to form a battery pack.

[0178] The battery pack can be applied to various devices, specifically, transportation means such as electric bicycles, electric cars, and hybrids, and ESS (Energy Storage Systems), but is not limited thereto, and can be applied to various devices that can use secondary batteries.

[0179] Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements made by those skilled in the art using the basic concept of the present invention defined in the following claims also fall within the scope of the present invention. [Explanation of symbols]

[0180] 100,100t,100s battery module 110 Battery Cell 210 1st side plate 220 Second Side Plate 600 Connecting member 700A Top Heatsink 700B Lower Heatsink 1000 Battery Packs 1100 Pack Tray

Claims

1. a battery module including: a battery cell stack in which a plurality of battery cells are stacked; a first side plate and a second side plate located on respective sides of the battery cell stack; and connecting members located on an upper portion and a lower portion of the battery cell stack, the connecting members connecting the first side plate and the second side plate; A pack tray for housing the battery module; and a heat sink including at least one cooling section through which a coolant flows; A battery pack comprising: the heat sink includes at least one of an upper heat sink located on an upper portion of the battery module and a lower heat sink located on a lower portion of the battery module; the first side plate and the second side plate are fixed to the pack tray; A battery pack, wherein the cooling portion of the upper heat sink is located on one side of the connecting member at an upper portion of the battery module, and the cooling portion of the lower heat sink is located on one side of the connecting member at a lower portion of the battery module.

2. the plurality of connecting members are provided at least in one of an upper side and a lower side of the battery cell stack, The battery pack according to claim 1 , wherein the connecting members are spaced apart from each other in a direction perpendicular to a stacking direction of the battery cells.

3. The battery pack according to claim 2 , wherein the cooling portion is disposed in a space between the connecting members spaced apart from each other.

4. The battery pack according to claim 1 , wherein the connecting member is provided singly at least at one of an upper side and a lower side of the battery cell stack.

5. The battery module is composed of a plurality of battery modules, The battery pack according to claim 1 , wherein the at least two battery modules are arranged along a stacking direction in which the battery cells are stacked.

6. The battery pack according to claim 5 , wherein the cooling portion passes through one side of the connecting member of any one of the battery modules and passes through one side of the connecting member of another battery module adjacent to the any one of the battery modules.

7. The cooling section includes a first cooling section and a second cooling section extending along one direction, 7. The battery pack of claim 1, wherein each of the upper heat sink and the lower heat sink further includes an inlet portion connected to the first cooling portion and through which a refrigerant flows, an outlet portion connected to the second cooling portion and through which the refrigerant is discharged, and a connecting portion connecting the first cooling portion and the second cooling portion.

8. The battery pack according to claim 7 , wherein the coolant flows along the inlet portion, the first cooling portion, the connecting portion, the second cooling portion, and the outlet portion to form a circulation structure.

9. The battery pack according to claim 7 , wherein the one direction is parallel to a stacking direction in which the battery cells are stacked.

10. The battery pack according to claim 7 , wherein the inlet portion and the outlet portion are located on the same side of the battery module, and the connecting portion is located on an opposite side to the inlet portion and the outlet portion.

11. The battery pack according to claim 1 , wherein the battery module further comprises a thermal resin layer located between the cooling portion and the battery cell stack.

12. 12. The battery pack of claim 11, wherein the thermal resin layer includes at least one of an upper thermal resin layer located between the cooling portion of the upper heat sink and the battery cell stack and a lower thermal resin layer located between the cooling portion of the lower heat sink and the battery cell stack.

13. each of the first side plate and the second side plate supports an outermost battery cell of the battery cell stack, and includes a support portion that is disposed perpendicular to a bottom portion of the pack tray, and a fixing portion that protrudes in a direction perpendicular to one surface of the support portion; The battery pack according to claim 1 , wherein the fixing portion is fixed to the pack tray.

14. the pack tray includes a mounting beam disposed on a top surface of the bottom of the pack tray; The battery pack of claim 13 , wherein the fixed portion is fixed to the mounting beam.

15. the battery cell stack includes a first battery cell stack and a second battery cell stack; The battery pack according to claim 1 , wherein the first battery cell stack and the second battery cell stack are spaced apart from each other along a direction perpendicular to a stacking direction in which the battery cells are stacked.

16. the first side plate extends to cover all of one side of the first battery cell stack and one side of the second battery cell stack; The battery pack of claim 15 , wherein the second side plate extends to cover the other side of the first battery cell stack and the other side of the second battery cell stack.

17. 16. The battery pack of claim 15, further comprising an insulating plate located between the first stack of battery cells and the second stack of battery cells.

18. each of the upper heat sink and the lower heat sink includes a plurality of cooling portions; the cooling portion of the upper heat sink is disposed on one or both sides of the connecting member at an upper portion of the first battery cell stack and an upper portion of the second battery cell stack; The battery pack of claim 15 , wherein the cooling portion of the lower heat sink is disposed on one or both sides of the connecting member below the first battery cell stack and below the second battery cell stack.

19. The battery cells are stacked in one direction from the first side plate to the second side plate, a compression pad is interposed at least in one of between adjacent battery cells, between one of the outermost battery cells and the first side plate, or between another of the outermost battery cells and the second side plate; 2. The battery pack according to claim 1, wherein, in an end of life (EOL) state, a deformation rate in a direction in which the battery cells are stacked is 12% or less, and a surface pressure applied to the battery cells is 0.9 MPa or less.

20. The module stiffness curve of the battery module is calculated in a range of a slope (MPa / %) of 0.00417 or more and 0.225 or less, 20. The battery pack of claim 19, wherein a module stiffness curve of the battery module corresponds to a relationship between a deformation rate of the first side plate and the second side plate and a surface pressure applied to the first side plate and the second side plate.

21. 20. The battery pack of claim 19, wherein the module stiffness curve of the battery module is derived by reflecting a degree to which the compression pad is compressed with respect to a surface pressure applied to the compression pad and the number of the compression pads in a frame stiffness curve of the first side plate and the second side plate.

22. A device comprising at least one battery pack according to claim 1.

Images