Pack case for electric vehicle, and battery pack comprising same

Abstract

The disclosed pack case comprises a plurality of side beams for forming a side wall, wherein the side beam includes an embedded cooling water-refrigerant heat exchanger: which has a cooling water flow path into or out of which cooling water circulating in an external heat exchanger flows, and a refrigerant flow path into or out of which a refrigerant circulating in a refrigeration cycle flows; and in which heat exchange is performed between the cooling water and the refrigerant.

Description

Pack case for electric vehicles and battery pack including the same

[0001] The present invention relates to a pack case suitable for mounting in an electric vehicle and a pack including the same.

[0002] This application claims the benefit of priority based on Korean Patent Application No. 10-2024-0192322 filed on December 20, 2024, and all contents disclosed in the document of said Korean patent application are incorporated herein as part of this specification.

[0003] Unlike primary batteries, secondary batteries are rechargeable and are currently the subject of extensive research and development due to their potential for miniaturization and high capacity. The demand for secondary batteries as an energy source is increasing rapidly due to the growing technological development and demand for mobile devices, as well as the rise of electric vehicles and energy storage systems driven by the contemporary need for environmental protection.

[0004] Rechargeable batteries are classified into coin batteries, cylindrical batteries, prismatic batteries, and pouch batteries according to the shape of the battery case. In rechargeable batteries, the electrode assembly mounted inside the battery case is a power generation device capable of charging and discharging, consisting of a laminated structure of electrodes and separators.

[0005] Since secondary batteries require continuous use over long periods, it is necessary to effectively control the heat generated during the charging and discharging process. To effectively dissipate the heat generated by secondary batteries, heat sinks (also called cooling plates) through which a refrigerant flows are widely used. Heat sinks are mounted on the bottom surface of a group of multiple secondary batteries, for example, a battery pack containing multiple batteries, and perform a cooling function by absorbing heat generated inside the pack using a refrigerant and releasing it to the outside.

[0006] However, if the amount of heat generated by the secondary battery is excessive and the cooling of the secondary battery is not carried out smoothly, a positive feedback chain reaction occurs in which the temperature rise of the secondary battery causes an increase in current, and the increase in current again causes a temperature rise, eventually leading to a catastrophic state of thermal runaway.

[0007] In addition, when secondary batteries are grouped in the form of modules or packs, a thermal propagation phenomenon occurs in which surrounding secondary batteries are continuously overheated due to thermal runaway occurring in one secondary battery. That is, when thermal runaway occurs in a battery module within a battery pack, a large amount of conductive dust, gas, and flames are ejected from the high-voltage terminal of the battery module, and consequently, dust accumulates on the high-voltage terminal of an adjacent battery module, and the thermal propagation phenomenon is triggered by heat transfer caused by the gas and flames.

[0008] The cooling of battery packs installed in electric vehicles is typically a water-cooling system using coolant, and the coolant is dissipated through heat exchangers such as radiators. While this water-cooling system poses no significant problems for battery packs in normal operation, it presents an issue where its cooling performance is insufficient to adequately cool the battery pack in the event of thermal events such as thermal runaway.

[0009] The present invention aims to provide a cooling structure capable of efficiently managing heat even when a thermal event occurs, in a pack case for an electric vehicle and a battery pack including the same.

[0010] However, the technical problems that the present invention aims to solve are not limited to those described above, and other unmentioned problems will be clearly understood by a person skilled in the art from the description of the invention below.

[0011] The present invention relates to a pack case having a plurality of side beams forming a side wall, and in one embodiment, the side beam has a cooling water flow path through which cooling water circulating in an external heat exchanger flows in and out, and a refrigerant flow path through which a refrigerant circulating in a refrigeration cycle flows in and out, and incorporates a cooling water-refrigerant heat exchanger in which heat exchange takes place between the cooling water and the refrigerant.

[0012] The above cooling water-refrigerant heat exchanger may be a plate-type heat exchanger in which a plurality of heat transfer plates are aligned and the plurality of heat transfer plates alternately communicate with the cooling water flow path and the refrigerant flow path.

[0013] The plurality of heat transfer plates are arranged alternately in a row, with a plurality of cooling water heat transfer plates and a plurality of refrigerant heat transfer plates, and the cooling water flow path communicates with the plurality of cooling water heat transfer plates, and the refrigerant flow path can communicate with the plurality of refrigerant heat transfer plates.

[0014] The above cooling water flow path is blocked and passes through the refrigerant heat transfer plate, exchanging heat with the refrigerant filled inside the refrigerant heat transfer plate, and the above cooling water flow path is blocked and passes through the cooling water heat transfer plate, exchanging heat with the cooling water filled inside the cooling water heat transfer plate.

[0015] The above cooling water-refrigerant heat exchanger may be equipped with a refrigerant valve at the inlet of the refrigerant path to open and close the inflow of the refrigerant.

[0016] The above cooling water-refrigerant heat exchanger is equipped with a cooling water valve that opens and closes the inflow of the cooling water at the inlet of the cooling water path, and the refrigerant valve and the cooling water valve can operate independently of each other.

[0017] The above cooling water-refrigerant heat exchanger can open the refrigerant valve when the preset temperature is exceeded.

[0018] In one embodiment, the pack case includes a base plate having a heat sink through which cooling water circulating through the external heat exchanger flows in and out, and the cooling water flow path of the cooling water-refrigerant heat exchanger and the cooling water flow path of the heat sink can be connected in series.

[0019] For example, the outlet of the cooling water flow path of the above cooling water-refrigerant heat exchanger can be connected to the inlet of the cooling water flow path of the above heat sink.

[0020] Meanwhile, the present invention may provide a battery pack comprising a pack case having the above configuration and at least one battery assembly mounted in a receiving space of the pack case.

[0021] The battery assembly may be cooled by a coolant-refrigerant heat exchanger built into the side beam and / or a heat sink provided on the base plate.

[0022] The pack case of the present invention, having the above-described configuration, incorporates a cooling water-refrigerant heat exchanger in a side beam forming a side wall, thereby cooling the side of a battery assembly mounted in the pack case. In particular, by using a low-temperature refrigerant circulating in a refrigeration cycle, the temperature of the cooling water circulating in the external heat exchanger can be further lowered, thereby improving the cooling performance of the entire pack case.

[0023] Thus, the pack case provided by the present invention can efficiently manage the heat of the battery pack even when a thermal event occurs.

[0024] However, the technical effects obtainable through the present invention are not limited to those described above, and other unmentioned effects will be clearly understood by a person skilled in the art from the description of the invention below.

[0025] The following drawings attached to this specification illustrate preferred embodiments of the present invention and serve to further enhance understanding of the technical concept of the present invention together with the detailed description of the invention provided below; therefore, the present invention should not be interpreted as being limited only to the matters described in such drawings.

[0026] FIG. 1 is a perspective view of a pack case according to one embodiment of the present invention.

[0027] FIG. 2 is an exploded perspective view of a side beam provided in the pack case of FIG. 1.

[0028] FIG. 3 is a drawing of a cooling water-refrigerant heat exchanger embedded in the side beam of FIG. 2.

[0029] Figure 4 is an enlarged view of the flow structure of a cooling water-refrigerant heat exchanger.

[0030] FIG. 5 is a diagram illustrating the overall flow of cooling water and refrigerant in the pack case of FIG. 1.

[0031] FIG. 6 is a schematic diagram illustrating lateral cooling for a side beam with an integrated cooling water-refrigerant heat exchanger.

[0032] The present invention is capable of various modifications and may have various embodiments, and specific embodiments are to be described in detail below.

[0033] However, this is not intended to limit the invention to specific embodiments, and it should be understood that it includes all modifications, equivalents, and substitutions that fall within the spirit and scope of the invention.

[0034] In the present invention, terms such as "comprising" or "having" are intended to specify the existence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood as not excluding in advance the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0035] Furthermore, 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 "immediately 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 "immediately below" the other part, but also cases where there is another part in between. Additionally, in the present application, being "placed on" may include cases where it is placed on the lower part as well as on the upper part.

[0036]

[0037] The present invention relates to a pack case having a plurality of side beams forming a side wall, and in one embodiment, the side beam has a cooling water flow path through which cooling water circulating in an external heat exchanger flows in and out, and a refrigerant flow path through which a refrigerant circulating in a refrigeration cycle flows in and out, and incorporates a cooling water-refrigerant heat exchanger in which heat exchange takes place between the cooling water and the refrigerant.

[0038] A pack case according to one embodiment of the present invention incorporates a cooling water-refrigerant heat exchanger in a side beam forming a side wall, thereby cooling the side of a battery assembly mounted in the pack case. In particular, by using a low-temperature refrigerant circulating in a refrigeration cycle, the temperature of the cooling water circulating in the external heat exchanger can be further lowered, thereby improving the cooling performance of the entire pack case.

[0039] Thus, the pack case provided by the present invention can efficiently manage the heat of the battery pack even when a thermal event occurs.

[0040] Hereinafter, specific embodiments of a pack case (100) and a battery pack (200) including the same according to the present invention will be described in detail with reference to the attached drawings. For reference, the directions of front, back, up, down, left, and right used to specify relative positions in the following description are intended to aid in understanding the invention, and unless otherwise specifically defined, the directions shown in the drawings are used as the reference.

[0041]

[0042] [First embodiment]

[0043] FIG. 1 is a perspective view of a pack case (100) according to an embodiment of the present invention, and FIG. 2 is an exploded perspective view of a side beam (130) provided in the pack case (100) of FIG. 1. With reference to FIG. 1 and FIG. 2, the overall configuration of the pack case (100) provided by the present invention will be described.

[0044] The pack case (100) illustrated as an example comprises a plurality of side beams (130) forming side walls. The pack case (100) comprises a base plate (110) forming a bottom surface, and the side beams (130) are joined along the edges of the base plate (110) to form the side walls of the pack case (100).

[0045] The side beam (130) incorporates a coolant-refrigerant heat exchanger (140). The coolant-refrigerant heat exchanger (140) is provided with a coolant flow path (142) through which coolant circulating through an external heat exchanger (300) flows in and out, and a refrigerant flow path (144) through which refrigerant circulating through a refrigeration cycle flows in and out. In the coolant-refrigerant heat exchanger (140), heat exchange occurs between the coolant and the refrigerant. The pack case (100) provided by the present invention can be applied to a battery pack (200) for an electric vehicle. When applied to an electric vehicle, the external heat exchanger (300) may be a radiator of the electric vehicle, and the refrigerant may be a refrigerant circulating through the air conditioning system of the electric vehicle.

[0046] FIG. 3 is a drawing of a cooling water-refrigerant heat exchanger (140) embedded in the side beam (130) of FIG. 2. The exemplary cooling water-refrigerant heat exchanger (140) of FIG. 3 is composed of a plate heat exchanger in which a plurality of heat transfer plates (146) are aligned, and the plurality of heat transfer plates (146) alternately communicate with a cooling water flow path (142) and a refrigerant flow path (144). Two types of heat fluids, cooling water and refrigerant, flow through the plate heat exchanger, and heat exchange occurs between the flowing cooling water and refrigerant. Generally, because the temperature of the refrigerant circulating in the refrigeration cycle is lower, heat exchange may occur in the cooling water-refrigerant heat exchanger (140) in a direction that lowers the temperature of the cooling water.

[0047] FIG. 4 is an enlarged view of the flow structure of a cooling water-refrigerant heat exchanger (140). A plurality of heat transfer plates (146) constituting the plate heat exchanger are arranged in a row with a plurality of cooling water heat transfer plates (147) and a plurality of refrigerant heat transfer plates (148) alternately. A cooling water flow path (142) communicates with a plurality of cooling water heat transfer plates (147) among all heat transfer plates (146), and similarly, a refrigerant flow path (144) communicates with a plurality of refrigerant heat transfer plates (148) among all heat transfer plates (146).

[0048] The cooling water passage (142) passes through the refrigerant heat transfer plate (148) while being blocked, thereby exchanging heat with the refrigerant filled inside the refrigerant heat transfer plate (148), and the refrigerant passage (144) passes through the cooling water heat transfer plate (147) while being blocked, thereby exchanging heat with the cooling water filled inside the cooling water heat transfer plate (147). This relative heat exchange between the cooling water and the refrigerant is performed alternately. That is, heat exchange is performed in such a manner that the cooling water passage (142) is immersed in the refrigerant one time, and the refrigerant passage (144) is immersed in the cooling water the next time.

[0049] Since the cooling water-refrigerant heat exchanger (140) is made of a plate heat exchanger, even if it is embedded in the narrow space provided by the side beam (130), it can achieve high heat transfer efficiency relative to its physical size.

[0050]

[0051] [Second embodiment]

[0052] FIG. 5 is a diagram illustrating the overall flow of cooling water and refrigerant in a pack case (100) provided by the present invention. The illustrated pack case (100) includes a base plate (110) having a heat sink (120) into which cooling water circulating through an external heat exchanger (300) flows in and out. A side beam (130) described in the first embodiment is coupled to the base plate (110) having the heat sink (120) to form the side wall of the pack case (100). The heat sink (120) may be formed integrally with the base plate (110) or may be manufactured separately and joined to the base plate (110).

[0053] A cooling water-refrigerant heat exchanger (140) built into a side beam (130) is provided with a cooling water path (142) and a refrigerant path (144), and a cooling water path (122) is also provided in a heat sink (120) provided in a base plate (110). To distinguish between the two cooling water paths (122, 142), the cooling water path (122) of the heat sink (120) is referred to as the second cooling water path below.

[0054] Referring to FIG. 5, the cooling water flow path (142) of the cooling water-refrigerant heat exchanger (140) and the second cooling water flow path (122) of the heat sink (120) are connected in series. For example, cooling water supplied from an external heat exchanger (300) is first supplied to the cooling water-refrigerant heat exchanger (140), and the outlet of the cooling water flow path (142) of the cooling water-refrigerant heat exchanger (140) can be connected to the inlet of the second cooling water flow path (122) of the heat sink (120). The outlet of the second cooling water flow path (122) leads to the external heat exchanger (300), thereby completing the cooling water circulation structure for the pack case (100).

[0055] According to the cooling water circulation structure of FIG. 5, cooling water is supplied to the heat sink (120) of the base plate (110) after passing through the cooling water-refrigerant heat exchanger (140) and the temperature is sufficiently lowered by the refrigerant. Accordingly, the cooling performance of the base plate (110), which contacts the battery assembly (210) mounted on the battery pack (200) over a large area, is improved. As a result, the heat management of the battery pack (200) can be efficiently performed by the pack case (100) of the present invention even when a thermal event occurs.

[0056] Also, referring to FIG. 5, the cooling water-refrigerant heat exchanger (140) may be equipped with a refrigerant valve (160) that opens and closes the inflow of refrigerant at the inlet of the refrigerant path (144). In addition, the cooling water-refrigerant heat exchanger (140) may be equipped with a cooling water valve (150) that opens and closes the inflow of cooling water at the inlet of the cooling water path (142), and in this case, the refrigerant valve (160) and the cooling water valve (150) may operate independently of each other.

[0057] By opening and closing the coolant valve (150), the supply of coolant can be temporarily restricted during the initial operation of the battery pack (200). Accordingly, the battery pack (200) can quickly reach a normal operating temperature.

[0058] On the other hand, the coolant-refrigerant heat exchanger (140) can open the refrigerant valve (160) when the temperature exceeds a preset temperature. For example, the preset temperature may correspond to a temperature for determining that a thermal event has occurred in the battery pack (200). By supplying refrigerant to the coolant-refrigerant heat exchanger (140) when a thermal event occurs, additional cooling performance can be secured to prevent, delay, or mitigate the thermal event.

[0059] To measure the temperature environment within the battery pack (200), the battery pack (200) may be equipped with temperature sensors at various locations in various numbers. Since the configuration in which one or more temperature sensors are provided in the battery pack (200) corresponds to known technology, a detailed description and illustration thereof will be omitted.

[0060] FIG. 6 is a schematic diagram illustrating lateral cooling for a side beam (130) incorporating a cooling water-refrigerant heat exchanger (140). The battery pack (200) provided by the present invention comprises a pack case (100) having the above configuration, and at least one battery assembly (210) mounted in a receiving space of the pack case (100). The battery assembly (210) is mounted on a base plate (110), and at least one side of the battery assembly (210) is in contact with or close to the side beam (130).

[0061] The battery assembly (210) may be cooled by a coolant-refrigerant heat exchanger (140) built into the side beam (130) and / or a heat sink (120) provided on the base plate (110). The method of cooling the battery assembly (210) may be achieved in various ways through the mutually independent operation of the aforementioned refrigerant valve (160) and coolant valve (150). Maximum cooling of the battery pack (200) may be achieved by supplying coolant and refrigerant to the coolant-refrigerant heat exchanger (140) built into the side beam (130) and also supplying coolant to the heat sink (120) provided on the base plate (110).

[0062]

[0063] The present invention has been described in more detail above through drawings and embodiments. However, the configurations described in the drawings or embodiments described in this specification are merely one embodiment of the present invention and do not represent all technical concepts of the present invention; therefore, it should be understood that various equivalents and modifications that can replace them may exist at the time of filing this application.

[0064] [Explanation of the symbol]

[0065] 100: Pack Case

[0066] 110: Base Plate

[0067] 120: Heatsink

[0068] 122: Second coolant flow path

[0069] 130: Side beam

[0070] 140: Cooling water-refrigerant heat exchanger

[0071] 142: Coolant flow path

[0072] 144: Refrigerant Flow Path

[0073] 146: Heat plate

[0074] 147: Cooling water heat transfer plate

[0075] 148: Refrigerant heat transfer plate

[0076] 150: Coolant valve

[0077] 160: Refrigerant valve

[0078] 200: Battery pack

[0079] 210: Battery Assembly

[0080] 300: External heat exchanger

Claims

1. A pack case having a plurality of side beams forming a side wall, The above side beam is, A pack case having a cooling water flow path through which cooling water circulating in an external heat exchanger flows in and out, and a refrigerant flow path through which refrigerant circulating in a refrigeration cycle flows in and out, and a cooling water-refrigerant heat exchanger in which heat exchange takes place between the cooling water and the refrigerant.

2. In Paragraph 1, The above cooling water-refrigerant heat exchanger is, A pack case that is a plate heat exchanger in which a plurality of heat transfer plates are aligned, and the plurality of heat transfer plates alternately communicate with the cooling water path and the refrigerant path.

3. In Paragraph 2, The above plurality of heat transfer plates consists of a plurality of cooling water heat transfer plates and a plurality of refrigerant heat transfer plates arranged alternately in a row, and The above cooling water passage communicates with the plurality of cooling water heat transfer plates, and A pack case in which the above refrigerant flow path communicates with the above plurality of refrigerant heat transfer plates.

4. In Paragraph 3, The above cooling water path passes through the refrigerant heat transfer plate while being blocked, and exchanges heat with the refrigerant filled inside the refrigerant heat transfer plate. A pack case in which the above refrigerant flow path passes through the above cooling water heat transfer plate while being blocked, and exchanges heat with the cooling water filled inside the above cooling water heat transfer plate.

5. In Paragraph 1, The above cooling water-refrigerant heat exchanger is, A pack case having a refrigerant valve at the inlet of the refrigerant path that opens and closes the inflow of the refrigerant.

6. In Paragraph 5, The above cooling water-refrigerant heat exchanger is, A cooling water valve for opening and closing the inflow of the cooling water is provided at the inlet of the cooling water passage. A pack case in which the refrigerant valve and the cooling water valve operate independently of each other.

7. In Paragraph 5, The above cooling water-refrigerant heat exchanger is, A pack case that opens the refrigerant valve when the preset temperature is exceeded.

8. In Paragraph 1, The above pack case includes a base plate having a heat sink through which cooling water circulating through the external heat exchanger flows in and out. A pack case in which the cooling water flow path of the above cooling water-refrigerant heat exchanger and the cooling water flow path of the above heat sink are connected in series.

9. In Paragraph 8, The outlet of the cooling water flow path of the above cooling water-refrigerant heat exchanger is, A pack case connected to the inlet of the coolant flow path of the heatsink.

10. A pack case according to any one of paragraphs 1 through 9; and At least one battery assembly mounted in the receiving space of the above-mentioned pack case; A battery pack including 11. In Paragraph 10, The above battery assembly is, A battery pack cooled by a cooling water-refrigerant heat exchanger built into the side beam and / or a heat sink provided on the base plate.

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