Cooling structure of battery pack

Abstract

A cooling structure of a battery pack that is disclosed comprises: a heat sink comprising a plurality of cooling flow paths; a plurality of battery assemblies longitudinally and / or transversely mounted on top of the heat sink; and a plurality of electrical components mounted on the front surface and / or the rear surface of the heat sink, wherein at least one of the plurality of electrical components has an insulating oil sealed therein, and heat accumulated in the insulating oil is discharged to the outside through the cooling flow paths of the heat sink.

Description

Cooling structure of the battery pack

[0001] The present invention relates to a cooling structure of a battery pack capable of providing a high-performance battery pack by allowing a heat sink forming the bottom surface of the battery pack to efficiently cool not only battery cells but also electrical components.

[0002] This application claims the benefit of priority to Republic of Korea Patent Application No. 10-2024-0038147, filed March 20, 2024, and Republic of Korea Patent Application No. 10-2024-0149590, filed October 29, 2024, the entire contents of which are incorporated herein by reference.

[0003] Unlike primary batteries, secondary batteries are rechargeable and, due to their potential for miniaturization and large capacity, have been the subject of extensive research and development in recent years. With increasing technological development and demand for mobile devices, and the emergence of electric vehicles and energy storage systems in response to the era's growing environmental concerns, demand for secondary batteries as an energy source is rapidly increasing.

[0004] Secondary batteries are classified into coin-shaped, cylindrical, square, and pouch-shaped batteries, depending on the shape of their battery cases. In secondary batteries, the electrode assembly mounted inside the battery case is a rechargeable, power-generating element comprised of a laminated structure of electrodes and a separator.

[0005] Because secondary batteries require continuous, long-term use, effective control of the heat generated during charging and discharging is essential. If secondary batteries are not properly cooled, a temperature rise triggers an increase in current, which in turn triggers a temperature rise, resulting in a positive feedback loop, ultimately leading to a catastrophic condition known as thermal runaway.

[0006] To effectively dissipate heat generated by secondary batteries, heat sinks (also called cooling plates) with circulating coolant are widely used. These heat sinks are mounted on the underside of a battery pack containing multiple secondary batteries, for example. They perform a cooling function by absorbing heat generated within the pack through coolant and dissipating it to the outside.

[0007] Battery packs are being applied in a variety of technological fields, and demand for battery packs for electric vehicles is currently very high. To increase driving range and enhance driving performance, battery packs for electric vehicles are gradually becoming higher-capacity and higher-performance. Furthermore, as the current required for rapid charging and driving cycles continues to increase, heat generation from busbars and electrical components is also increasing. Consequently, battery pack cooling performance must also be improved.

[0008] The battery pack primarily cools the battery cells, but does not provide cooling for the electrical components. This can lead to the high heat from the electrical components being transferred to the battery cells through the busbars, potentially overheating the cells. This can lead to performance degradation or thermal runaway.

[0009] The purpose of the present invention is to provide a cooling structure for a battery pack that can make a high-performance battery pack safer by ensuring that a heat sink forming the bottom surface of the battery pack efficiently cools not only the battery cells but also the electrical components.

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

[0011] The present invention relates to a cooling structure for a battery pack, and in one example, comprises a heat sink including a plurality of cooling channels, a plurality of battery assemblies mounted vertically and / or horizontally on the heat sink, and a plurality of electrical components mounted on the front and / or rear of the heat sink, wherein at least one of the plurality of electrical components has insulating oil sealed therein, and heat accumulated in the insulating oil is discharged to the outside through the cooling channels of the heat sink.

[0012] In one embodiment, the plurality of cooling channels are provided along the entire length of the heat sink.

[0013] For example, the heat sink may be formed integrally with a cooling passage by extrusion molding, and the plurality of cooling passages may be formed by a plurality of ribs spaced apart in the width direction along the entire length of the heat sink.

[0014] A thermal interface material (TIM) may be interposed between the heat sink and the electrical component having insulating oil sealed inside.

[0015] Additionally, a fin structure may be interposed between the electrical component having insulating oil sealed inside and the heat sink.

[0016] The above fin structure can be formed on the bottom surface of the electrical component with insulating oil sealed inside, or on the top surface of the heat sink.

[0017] And, the heat transfer material can cover the entire fin structure.

[0018] In one embodiment, the electrical component having insulating oil sealed inside may be a Battery Disconnection Unit (BDU).

[0019] Additionally, insulating oil may be sealed inside the BMS (Battery Management System) connected to the BDU and busbar.

[0020] In one embodiment, the electrical component having insulating oil sealed inside may be provided with a relief valve.

[0021] According to the cooling structure of the battery pack described above, heat generated from the electrical components is stored in the insulating oil sealed inside before being transferred to the battery cells, while being discharged to the outside via the coolant flowing through the heat sink. Consequently, heat from the electrical components is prevented from entering the battery cells, resulting in a higher-performance battery pack.

[0022] In addition, since the heat sink forming the bottom surface of the battery pack is an extruded heat sink with a cooling path formed integrally from the front to the rear, efficient cooling can be achieved for electrical components placed on the front and / or rear of the heat sink.

[0023] However, the technical effects that can be obtained through the present invention are not limited to the above-described effects, and other effects that are not mentioned can be clearly understood by those skilled in the art from the description of the invention described below.

[0024] The following drawings attached to this specification illustrate preferred embodiments of the present invention, and together with the detailed description of the invention described below, serve to further understand the technical idea of ​​the present invention, and therefore, the present invention should not be interpreted as being limited to matters described in such drawings.

[0025] FIG. 1 is a drawing illustrating a battery pack to which a cooling structure of a battery pack according to one embodiment of the present invention is applied.

[0026] Figure 2 is an exploded perspective view of the battery pack of Figure 1.

[0027] FIG. 3 is a drawing illustrating an example of an electrical component mounted on the battery pack of FIG. 1.

[0028] Figure 4 is a cross-sectional view taken along line “AA” of Figure 1.

[0029] FIG. 5 is a drawing illustrating one embodiment of a structure that promotes heat transfer between a heat sink and a component.

[0030] The present invention can be modified in various ways and has many embodiments, and specific embodiments will be described in detail below.

[0031] However, this is not intended to limit the present invention to a specific embodiment, but should be understood to include all modifications, equivalents, or substitutes included in the spirit and technical scope of the present invention.

[0032] In the present invention, it should be understood that terms such as “include” or “have” are intended to specify the presence of a feature, number, step, operation, component, part or combination thereof described in the specification, but do not exclude in advance the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts or combinations thereof.

[0033] Additionally, in the present invention, when a part such as a layer, film, region, or plate is described as being "on" another part, this includes not only cases where it is "directly above" the other part, but also cases where there is another part in between. Conversely, when a part such as a layer, film, region, or plate is described as being "under" another part, this includes not only cases where it is "directly below" the other part, but also cases where there is another part in between. Furthermore, in the present application, "being placed on" may include cases where it is placed below as well as above.

[0034]

[0035] The present invention relates to a cooling structure for a battery pack, and in one example, comprises a heat sink including a plurality of cooling channels, a plurality of battery assemblies mounted vertically and / or horizontally on the heat sink, and a plurality of electrical components mounted on the front and / or rear of the heat sink, wherein at least one of the plurality of electrical components has insulating oil sealed therein, and heat accumulated in the insulating oil is discharged to the outside through the cooling channels of the heat sink.

[0036] According to the cooling structure of the battery pack described above, heat generated from the electrical components is stored in the insulating oil sealed inside before being transferred to the battery cells, while being discharged to the outside via the coolant flowing through the heat sink. Consequently, heat from the electrical components is prevented from entering the battery cells, resulting in a higher-performance battery pack.

[0037] Hereinafter, specific embodiments of the cooling structure of a battery pack according to the present invention will be described in detail with reference to the attached drawings. Note that the directions used to designate relative positions in the following description, such as front-back, up-down, left-right, etc., are intended to aid understanding of the invention, and unless otherwise specified, the directions depicted in the drawings will be used as a reference.

[0038]

[0039] [First Embodiment]

[0040] FIG. 1 is a drawing showing a battery pack (10) to which a cooling structure of a battery pack according to one embodiment of the present invention is applied, FIG. 2 is an exploded perspective view of the battery pack (10), and FIG. 3 is a drawing showing an example of an electrical component (300) mounted on the battery pack (10) of FIG. 1.

[0041] The present invention relates to a cooling structure of a battery pack, and more particularly, to a cooling structure of a battery pack that can effectively cool not only heat generated from a battery assembly (200) but also heat generated from an electrical component (300). Referring to FIGS. 1 to 3, the cooling structure of a battery pack according to the present invention will be described in detail.

[0042] The battery pack (10) includes a heat sink (100) that functions as a bottom plate of a battery housing that accommodates at least one, and in most cases, multiple, battery assemblies (200). The battery assembly (200) refers to an assembly of multiple battery cells in which multiple battery cells are structurally and electrically connected. Depending on the structure of connecting the multiple battery cells, the battery assembly (200) may be expressed by various terms such as a battery module, a battery block, a battery unit, etc. The present invention does not specifically limit the structure of the assembly of multiple battery cells mounted on the heat sink (100). The heat sink (100) includes a plurality of cooling channels (112). The plurality of cooling channels (112) provided in the heat sink (100) may be formed in various ways. For example, the heat sink (100) may be divided into a brazing heat sink and an extrusion heat sink depending on its structure or manufacturing method. Brazed heat sinks, which form a flow path by brazing two plates together, offer a high degree of freedom in flow path design. However, the deterioration of the material properties hinders structural rigidity. In contrast, extruded heat sinks, manufactured as a continuous body via extrusion, offer advantages in structural rigidity. However, they only allow for straight flow paths, resulting in a large number of ports and the need for connecting pipes, which can take up valuable space.

[0043] The cooling structure of the battery pack according to the present invention can be applied to heat sinks (100) of various specifications, but it is preferable that a plurality of cooling channels (112) are provided along the entire length of the heat sink (100). Specifically, it is preferable that a plurality of cooling channels (112) are formed for the entire area occupied by the battery assembly (200) and electrical components (300) accommodated or mounted in the battery pack (10).

[0044] A plurality of battery assemblies (200) are mounted vertically and / or horizontally on a heat sink (100). At least one electrical component (300) is mounted on the heat sink (100). In a relative arrangement relationship with the battery assembly (200), at least one electrical component (300) may be positioned along one edge of the heat sink (100) adjacent to the outermost battery assembly (200). One edge of the heat sink (100) on which the electrical component (300) is mounted may be the front or rear of the battery pack (10). The electrical component (300) refers to a component, module, or device that controls and monitors the charging and discharging of the entire battery assembly (200) to ensure that the function of the battery pack (10) is fully exerted.

[0045] Examples of the electrical components (300) of the battery pack (10) include a BDU (310) (Battery Disconnection Unit), a BMS (320) (Battery Management System), etc. The BDU (310) is a module that combines a relay, a current sensor, a pre-charge resistor, a fuse, etc., and is an important module that connects the battery and the inverter to distribute high voltage and high current, and performs emergency shutdown, etc. in case of an abnormality to prevent accidents. In addition, the BMS (320) is a system that is installed to manage the battery performance and lifespan in an optimal state, and measures the current, voltage, temperature, etc. of the battery through a sensor and controls the battery so that it can exhibit optimal performance by identifying it in advance.

[0046] When a coolant (e.g., coolant) flows through a plurality of cooling channels (112) provided in the heat sink (100), the coolant cools the battery assembly (200) and electrical components (300) above the heat sink (100) to prevent them from overheating. Since the battery assembly (200) generates high heat during charging and discharging, and overheating of the battery cell can cause serious accidents such as thermal runaway or heat transmission, the battery pack (10) focuses on cooling the battery assembly (200). In contrast, cooling of the electrical components (300) has not been separately considered, and as the battery pack (10) becomes more high-performance and has higher capacity, the high heat of the electrical components (300) is transferred to the battery assembly (200) through the bus bar (312), which can cause the battery assembly (200) to heat up.

[0047] In order to solve the problem of the battery assembly (200) being adversely affected by overheating of the electrical components (300), the cooling structure of the battery pack (10) according to the present invention has an insulating oil (330) sealed inside at least one of the plurality of electrical components (300), and the heat accumulated in the insulating oil (330) is discharged to the outside through the cooling path (112) of the heat sink (100). The insulating oil (330) refers to oil used for the purpose of electrical insulation, and generally, highly refined, low-viscosity petroleum-based lubricating oil is used. Although the main purpose is electrical insulation, it can also play a cooling role by preventing moisture from penetrating and dissipating generated heat.

[0048] Since the insulating oil (330) has a very high heat transfer rate and heat capacity compared to air, it can play a role in heat dissipation and cooling, and accordingly, heat generated inside the electrical component (300) is effectively accumulated in the insulating oil (330). The heat accumulated in the insulating oil (330) is transferred to the heat sink (100) in contact with the surface of the electrical component (300) in the form of heat conduction, and the heat transferred to the heat sink (100) is transferred to the refrigerant and then ultimately discharged to the outside of the battery pack (10).

[0049] Referring to FIGS. 1 and 2, the heat sink (100) illustrated as an example corresponds to an extruded heat sink. The illustrated heat sink (100) is formed integrally with a cooling channel (112) by extrusion molding, and a plurality of cooling channels (112) are formed in parallel by a plurality of ribs (110) spaced apart in the width direction (W) along the entire length direction (L) of the heat sink (100).

[0050] In order to allow the refrigerant to circulate along the plurality of cooling channels (112), the open surfaces of the heat sink (100) are closed with several end plugs (120). The open surfaces of the heat sink (100) are surfaces located at both ends in the longitudinal direction (L), and due to the characteristics of the extruded product, both ends of the heat sink (100) in the longitudinal direction (L) are open. For the convenience of explanation, the two open surfaces are referred to as the first surface and the second surface, respectively. Here, the longitudinal direction (L) is the extrusion direction of the heat sink (100), that is, the direction in which the plurality of ribs (110) extend, and the width direction (W) is the direction orthogonal to the longitudinal direction (L) on a plane in which the plurality of cooling channels (112) are spaced apart from each other.

[0051] The end plug (120) includes an inlet plug (122), an outlet plug (124), and a return plug (126). On the first side located at the front in the drawing, a central inlet plug (122) is coupled, and on both sides thereof, a pair of outlet plugs (124) are coupled. An inlet port (123) is arranged on the inlet plug (122), and an outlet port (125) is arranged on the outlet plug (124). In addition, a return plug (126) is coupled on the second side located at the rear in the drawing. The cooling channel (112) closed by the inlet plug (122) forms an inlet channel, and the cooling channel (112) closed by the outlet plug (124) forms an outlet channel. The return plug (126) forms a return channel connecting the inlet channel to the outlet channel. By this flow path formation, the refrigerant introduced into the inlet flow path through the central inlet port (123) hits the return plug (126) and branches off to the left and right to enter the outlet flow path, and the refrigerant flowing through the outlet flow path is discharged through the outlet port (125). However, the cooling flow path (112) configuration of the heat sink (100) is only one example shown in the drawing, and the heat sink (100) can of course be equipped with cooling flow paths (112) of various shapes and structures different from this.

[0052] "130", which is not described in the drawing, is a plate member that surrounds the four sides of the heat sink (100), and a space within the pack in which the battery assembly (200) and the electrical components (300) are mounted is formed by the plate member (130). In addition, a lid, which is not shown, forms a cover of the battery pack (10), thereby protecting the interior of the battery pack (10) from the outside.

[0053] FIG. 4 is a cross-sectional view taken along the line "AA" of FIG. 1. Referring to FIG. 4, a heat transfer material (400) (TIM) is interposed between an electrical component (300) and a heat sink (100) having insulating oil (330) sealed therein. This heat transfer material (400) may also be interposed between the battery assembly (200) and the heat sink (100). Referring to FIG. 2, a heat transfer material (400) may be applied to an appropriate thickness on the heat sink (100), and the battery assembly (200) and the electrical component (300) may be mounted on top of the applied heat transfer material (400). The heat transfer material (400) may be a curable material, for example, a thermal resin, that solidifies over time to form an adhesive state so as to secure the battery assembly (200) and the electrical component (300) to the heat sink (100).

[0054] As described above, the electrical component (300) having insulating oil (330) sealed inside may be a BDU (310) (Battery Disconnection Unit). The BDU (310) is connected to the battery assembly (200) by a bus bar (312), and belongs to an electrical component (300) with high heat generation because it handles high voltage and high current. Since the BDU (310) and the battery assembly (200) are connected by the bus bar (312), the high heat generated in the BDU (310) can flow to the battery assembly (200) along the thermally conductive bus bar (312). Therefore, by sealing the insulating oil (330) inside the BDU (310) and effectively releasing the heat to the heat sink (100), the heat transferred to the battery assembly (200) can be reduced.

[0055] And, depending on the embodiment, the BMS (320) (Battery Management System) may also be connected to the BDU (310) via a bus bar (312). In this case, it may be desirable to seal the inside of the BMS (320) with insulating oil (330) to prevent overheating.

[0056] And, referring to FIG. 4, the electrical component (300) having insulating oil (330) sealed inside may be equipped with a relief valve (340). The relief valve (340) is a safety device that opens the valve to relieve the internal pressure when the pressure inside the electrical component (300) exceeds a set value. When the heat generated in the electrical component (300) abnormally increases, the insulating oil (330) may boil locally, which may cause the internal pressure of the electrical component (300) to rapidly increase. In order to respond to such an emergency, the electrical component (300) may be equipped with a relief valve (340), and an accident in which the electrical component (300) is damaged and the insulating oil (330) is completely leaked due to the operation of the relief valve (340) may be prevented.

[0057]

[0058] [Second Embodiment]

[0059] FIG. 5 is a drawing illustrating one embodiment of a structure that promotes heat transfer between a heat sink (100) and an electrical component (300). Referring to FIG. 5, a fin structure (500) is interposed between an electrical component (300) having insulating oil (330) sealed therein and the heat sink (100). The fin structure (500) expands the heat transfer area, and thereby the heat of the electrical component (300) having insulating oil (330) sealed therein is transferred more quickly to the heat sink (100). That is, the cooling of the electrical component (300) is promoted by the fin structure (500), and the heat of the electrical component (300) is more effectively suppressed from being transmitted to the battery assembly (200).

[0060] The fin structure (500) may be formed on the bottom surface of the electrical component (300) in which insulating oil (330) is sealed inside, or on the upper surface of the heat sink (100). FIG. 5 illustrates an embodiment in which the fin structure (500) is integrally formed on the upper surface of the heat sink (100). When the fin structure (500) is formed on the heat sink (100), if the heat sink (100) is an extruded heat sink, the fin structure (500) may be formed along the longitudinal direction (L) of the heat sink (100) in the same direction as the formation of the rib (110). Accordingly, since the fin structure (500) on the extruded heat sink can be formed along the entire length of the heat sink (100), the fin structure (500) can be interposed not only on the electric component (300) but also on the bottom surface of the battery assembly (200), and cooling of the battery assembly (200) can also be promoted.

[0061] The fin structure (500) and the heat transfer material (400) may be applied together. In order for the heat dissipation function of the fin structure (500) and the heat transfer material (400) to be fully exerted, the heat transfer material (400) may cover the entire fin structure (500). That is, it may be preferable that the fin structure (500) be covered with the heat transfer material (400), thereby eliminating a space that hinders heat transfer, such as an air layer, in the heat transfer path between the electrical component (300) and the heat sink (100).

[0062]

[0063] The present invention has been described in more detail through drawings and examples. However, the configurations described in the drawings or examples described in this specification are merely embodiments of the present invention and do not represent all of the technical ideas of the present invention. Therefore, it should be understood that various equivalents and modified examples may exist as of the time of this application.

[0064]

[0065] [Explanation of symbols]

[0066] 10: Battery pack

[0067] 100: Heatsink

[0068] 110: Live

[0069] 112: Cooling oil

[0070] 120: End plug

[0071] 122: Inlet plug

[0072] 123: Inlet port

[0073] 124: Outlet plug

[0074] 125: Outlet Port

[0075] 126: Return plug

[0076] 130: Plate member

[0077] 200: Battery assembly

[0078] 300: Battlefield

[0079] 310: BDU

[0080] 312: Bus bar

[0081] 320: BMS

[0082] 330: Insulating oil

[0083] 340: Relief valve

[0084] 400: Heat transfer material

[0085] 500: Fin structure

Claims

1. A heat sink comprising multiple cooling channels; A plurality of battery assemblies mounted vertically and / or horizontally on the heat sink; and A plurality of electrical components mounted on the above heat sink; Including, A cooling structure of a battery pack, wherein at least one of the above-mentioned plurality of electrical components has insulating oil sealed therein, and heat accumulated in the insulating oil is discharged to the outside through a cooling passage of the heat sink.

2. In paragraph 1, The above plurality of cooling channels are: A cooling structure of a battery pack provided along the entire length of the above heat sink.

3. In paragraph 2, The above heat sink is formed integrally with the cooling channel by extrusion molding. A cooling structure of a battery pack, wherein the plurality of cooling channels are formed by a plurality of ribs spaced apart in the width direction along the entire length of the heat sink.

4. In paragraph 1, A cooling structure of a battery pack, in which a thermal transfer material (TIM) is interposed between the electrical components with insulating oil sealed inside and the heat sink.

5. In paragraph 4, A cooling structure of a battery pack, in which a fin structure is interposed between the electrical components having insulating oil sealed inside and the heat sink.

6. In paragraph 5, The above pin structure, A cooling structure of a battery pack formed on the bottom surface of a component with insulating oil sealed inside, or on the upper surface of the heat sink.

7. In paragraph 5, The above heat transfer material is, A cooling structure of the battery pack that covers the entire above fin structure.

8. In paragraph 1, The cooling structure of the battery pack is the BDU (Battery Disconnection Unit), which is an electrical component with insulating oil sealed inside.

9. In paragraph 8, A cooling structure of a battery pack, with insulating oil sealed inside the BMS (Battery Management System) connected to the above BDU and busbar.

10. In paragraph 1, The cooling structure of the battery pack, which has an insulating oil sealed inside and a relief valve.

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