JP5718549B2 - Medium and large battery packs with excellent cooling efficiency - Google Patents

Description

  The present invention relates to a medium-sized or large-sized battery pack having high cooling efficiency, and more particularly, to a medium-sized or large-sized battery pack having a battery module including a plurality of unit modules stacked in a horizontal direction. The module is vertically upright on one side, the battery module is mounted in a sealed space of the housing member, and the housing member has a refrigerant inlet at the upper or lower end on one side of the housing member. The refrigerant discharge port is provided at the upper end or lower end on the opposite side of the housing, and the battery module is configured such that the upper end surface or lower end surface of the battery module is inclined toward the refrigerant inlet by a predetermined angle. A refrigerant mounted in the housing member and thereby parallel to the battery module The refrigerant introduced through the inlet vertically penetrates the unit module and is then discharged to the opposite side, and the gap formed between the unit modules (vertical direction) on the inclined upper or lower end surface of the battery module. Are arranged in parallel to the direction in which the refrigerant is introduced, thereby improving the cooling efficiency and cooling uniformity of the battery module, while the battery pack relates to a battery pack having a compact structure.

  One of the biggest problems caused by vehicles using fossil fuels such as gasoline and diesel oil is the occurrence of air pollution. A technique for using a secondary battery that can be charged and discharged as a power source for a vehicle has attracted a great deal of attention as one method for solving the above problems. As a result, electric vehicles (EV) that are operated using only batteries and hybrid electric vehicles (HEV) that use batteries and conventional engines jointly have been developed. Some of the electric vehicles and hybrid electric vehicles are currently in commercial use. Nickel-hydrogen (Ni-MH) secondary batteries are used as the main power source for electric vehicles (EV) and hybrid electric vehicles (HEV). However, in recent years, lithium-ion secondary batteries have been tried.

  High power and high capacity are used for such secondary batteries, as used as a power source for electric vehicles (EV) and hybrid electric vehicles (HEV). For this purpose, a plurality of small secondary batteries (unit cells) are connected in series or in parallel so as to constitute a battery module, and a plurality of battery modules constitute a battery pack. Are connected to each other in parallel or in series.

  However, in such high power and high capacity secondary batteries, a large amount of heat is generated from the unit cells during charging and discharging of the unit cells. If the heat generated from the unit cell during charging and discharging of the unit cell is not efficiently removed, the heat is stored in the unit cell, resulting in deterioration of the unit cell. As a result, there is a need to provide a cooling system for cooling a vehicle battery pack that is a high power and large capacity secondary battery.

  One of the points that should be fully considered when installing a cooling system is to minimize the increase in the volume of the battery pack for the cooling system. In general, the refrigerant inlet is formed such that the refrigerant flows along the outer surface of the battery module, as well as through the interior of the battery module to improve the cooling efficiency of the cooling system. However, the structure of the refrigerant flow path is very complicated and is a factor that increases the volume of the battery pack. For this reason, the inclined channel is formed in a part of the battery module so that the refrigerant flow can be guided in an inclined manner as shown in FIG.

  Referring to FIG. 1, a battery pack cooling system 1 includes a battery module 2 having a plurality of batteries, a refrigerant inlet 3 attached to the lower end of the battery module in an inclined manner, and an inclined manner. And a refrigerant discharge port 4 attached to the upper end of the battery module 2. The battery module 2 includes a plurality of unit modules 5 electrically connected to each other, and the unit modules 5 are stacked in the horizontal direction, while each of the unit modules is vertically erected on one side. Each unit module 5 includes a plurality of secondary batteries 6 that are electrically connected to each other. A small gap is formed between the secondary batteries 6 of each battery module 5, and the refrigerant flows through the gap. As a result, the refrigerant introduced through the refrigerant inlet 3 flows along the flow path in order to remove the heat generated from the respective secondary batteries 6, and then the refrigerant outlet 4 attached to the upper end of the battery module 2. It is discharged through.

  However, the battery pack cooling system 1 configured as shown in FIG. 1 has the following problems.

  First, since the refrigerant inlet 3 and the refrigerant outlet 4 are respectively attached to the lower end and the upper end of the battery module 2 in the form of a duct, the height of the battery pack increases with the size of the duct. In particular, the lower duct in which the width of the duct is gradually reduced from the refrigerant inlet 3 is attached to the lower part of the rectangular battery module 2, and the upper duct whose width gradually increases toward the refrigerant outlet 4 is It is attached to the rectangular upper part of the battery module 2. For this reason, additional space for installing the upper and lower ducts is necessary. When a battery module 2 comprising unit modules 5 that are stacked horizontally and each unit module 5 is vertically upright on one side is introduced into the restricted interior space of the vehicle, the battery The increased height of the pack cooling system acts as a significant obstacle.

  As a result, various technologies have been developed to configure the cooling system, and flow paths are formed as shown in FIG. 1, while making the best use of the battery module and the space used for mounting around it. To do.

  In this regard, Patent Document 1 and Patent Document 2 disclose a cooling system for a medium- or large-sized battery pack, and the battery module is mounted in the pack case while the battery module itself is inclined at a predetermined angle. Thereby, the refrigerant flow path is formed in the battery pack without the installation of the duct for introducing the refrigerant and the duct for discharging the refrigerant. Similarly, Patent Document 1 discloses a technique for inclining a unit cell by a predetermined angle in order to form a flow path while mounting a plurality of unit cells in a housing of a small battery module. In the disclosed cooling system, the desired refrigerant flow path is formed by making maximum use of the internal space of the pack case to which the battery module is attached or the housing of the battery module. As a result, the disclosed cooling system suggests the possibility of manufacturing a battery pack having a smaller size than the duct structure as shown in FIG.

  However, the disclosed cooling system has the following problems in terms of operation efficiency as in the structure of FIG.

  In particular, the refrigerant introduced through the refrigerant inflow port collides with the outer surface of the unit module or the secondary battery in the vertical direction, and then enters each unit module in the flow path formed between the unit modules. It introduce | transduces in the flow path formed between the secondary batteries (unit cell) to comprise. The refrigerant collides with the outer surface of the unit module in the vertical direction and is then introduced into the refrigerant flow path, so that the cooling efficiency can be improved through the formation of a spiral. However, in a battery module including a plurality of unit modules (or secondary batteries) stacked with high integration, the fluid refrigerant meets a high flow resistance. As a result, when the unit modules (or secondary batteries) are arranged at further reduced intervals to reduce the total size of the battery pack, with the result that the refrigerant flow path becomes narrower, the refrigerant drive source (e.g. The blower fan) needs to generate a high driving force necessary to increase the flow rate of the refrigerant.

  Similarly, the refrigerant inlet is formed in the longitudinal direction of the unit module (or secondary battery). Therefore, a medium-sized battery pack and a large-sized battery pack constituted by a structure in which a plurality of unit modules are stacked to provide high output and large capacity with the result that the width of each unit module is larger than the length of each unit module In the battery module, the non-uniformity of the cooling of the battery pack is very high. In particular, the absolute amount of refrigerant introduced into the unit module (or secondary battery) closest to the refrigerant inlet is the amount of refrigerant introduced into the unit module (or secondary battery) farthest from the refrigerant inlet. Less than. As a result, battery pack cooling non-uniformity is high and is even more critical in the above structure with high flow resistance.

As a result, there is a high need for techniques that basically solve the above problems.
Japanese Patent Application Laid-Open No. 2004-22317 Korean Patent Application Publication No. 2005-35478 Korean Patent Application No. 2005-99871

  Therefore, the present application solves the above problems and other technical problems to be solved.

  In particular, the object of the present invention is that the battery module is mounted in the housing member such that the battery module is inclined at a predetermined angle, so that the naturally inclined flow path is above the housing member and the battery module. And a structure formed by a gap formed between the end surface and a gap formed between the housing member and the lower end surface of the battery module. It is to provide a battery pack having a compact structure without increasing the size.

  Another object of the present invention is that the gap formed between the unit modules is arranged parallel to the direction in which the refrigerant is introduced, whereby the supply of the refrigerant to the battery modules is efficiently achieved, and each of the battery modules The amount of refrigerant supplied to the compartment is uniform, thereby providing a battery pack configured with a structure that improves cooling efficiency and cooling uniformity.

  It is a further object of the present invention to provide a battery pack having a structure in which the shape of the frame at the lower end constituting the battery pack matches the internal structure of the vehicle, whereby the battery pack is stably attached to the vehicle.

  Referring to the present invention, the above and other objects are directed to a medium or large size that includes a plurality of unit modules that are stacked horizontally and each unit module is vertically upright on one side. In a battery pack, in which a battery module is mounted in a sealed space of a housing member, the housing member has a refrigerant inlet at an upper end or a lower end of one side of the housing member. The refrigerant discharge port is provided at the lower end or the upper end of one side of the housing member, and the battery module is configured such that the upper end surface or the lower end surface of the battery module is inclined toward the refrigerant inlet by a predetermined angle. In the housing member, thereby providing a refrigerant inlet parallel to the battery module. The refrigerant introduced next flows vertically through the unit module and then is discharged to the opposite side, and the gap formed between the unit modules on the inclined upper end surface or lower end surface of the battery module is in the direction in which the refrigerant is introduced. This is achieved by the definition of a medium or large battery pack, characterized in that it is arranged in parallel.

  As described above, the battery pack according to the present invention has a structure in which a battery module including a plurality of unit modules electrically connected to each other or two or more battery modules are mounted in a housing member. Composed.

  Each unit module is a battery cell that can be charged and discharged, or a combination of two or more battery cells.

  As used herein, “electrical connection” and “combination” refer to each other in series and / or in order to provide a battery pack having a desired output and capacity, preferably high output and large capacity. It means the connection of unit modules or battery cells in parallel with each other. For example, each battery cell includes an anode, a cathode, a separator, and an electrolyte, and each battery cell is in a sealed container so that each battery cell can be charged and discharged. It is attached. Preferably, each battery cell may be a lithium-ion battery cell, a lithium-ion polymer battery cell, or a nickel-hydrogen battery cell.

  In the battery pack according to the present invention, the refrigerant inlet is formed at the upper or lower end on one side of the housing member parallel to the gap (vertical flow path) between the inclined unit modules, as described above. . As a result, the refrigerant inlet is formed on the long side of a medium-sized or large-sized battery module including a plurality of upright unit modules.

  In general, the length of the long side of a battery module including a plurality of unit modules is limited by the number of unit modules used. For example, on the assumption that rectangular unit modules are used, the length of each unit module is a, the width of each unit module is b, and the thickness of each unit module is c , And if the number of unit modules used is x, a battery module configured by stacking x unit modules is a and c × x with the unit modules in firm contact with each other. It is formed in the form of a hexahedron having a side length, b height.

  This relationship will be described in more detail with reference to FIG. 2, which illustrates a battery module according to a preferred embodiment of the present invention. Referring to FIG. 2, the battery module 20 includes x unit modules 10. On the assumption that the length of each unit module is a, the width of each unit module is b, and the thickness of each unit module is c, the side length of the battery module is high. It is necessary to stack unit modules to satisfy the following inequality a <c × x for output and large capacity. In this case, the length of the long side of the battery module is c × x.

  According to the present invention, the refrigerant inlet is arranged on one side of the housing member parallel to the gap between the unit modules (vertical flow path), and therefore the refrigerant inlet is on the long side (c Xx) is formed at a predetermined position.

  This structure provides various effects. First, the flow resistance caused when refrigerant is introduced into the vertical flow path between the unit modules is reduced, thus increasing the cooling efficiency of the battery module. Second, the length between the refrigerant inlet and each vertical channel section furthest from the refrigerant inlet is reduced, thus increasing the cooling uniformity of the battery module. Thirdly, the refrigerant inlet is formed in the shape of a series of through holes corresponding to the length of the long side of the battery module, and therefore the refrigerant can be flowed with a small driving force.

  In relation to the first effect, the refrigerant introduced in the horizontal direction through the refrigerant inlet formed on one side of the housing member has a vertical flow path (parallel to the direction in which the refrigerant is introduced). It is naturally introduced into the gap between each unit module. As a result, flow resistance is greatly reduced. From a macro viewpoint, the refrigerant flows in the vertical direction through each unit module. From a macro perspective, on the other hand, the flow gradient is gradually lowered from the refrigerant inlet. As a result, the flow resistance of the refrigerant is reduced and the cooling efficiency is further maximized using a small driving force.

  In relation to the second effect, the distance between the refrigerant inlet and each vertical channel section furthest from the refrigerant inlet is limited by the length a of each unit module. As a result, when considering the fact that the distance between the refrigerant inlet and each vertical channel section of the conventional battery module increases with the length of the long side of the battery module, the refrigerant flow The distance between the inlet and each vertical channel section furthest from the refrigerant inlet is very small. As a result, it becomes possible to greatly reduce the cooling non-uniformity in each vertical channel section furthest from the refrigerant inlet.

  In connection with the third effect, the through holes constituting the refrigerant inlet increase the amount of refrigerant introduced per unit time, and therefore the refrigerant flow is enabled by a small driving force. At the same time, it is possible to evenly distribute the refrigerant over a wide area of the battery module. For this purpose, it may be considered to provide a structure in which the coolant inlet is formed directly at the upper end of the housing member facing the upper end surface of the battery module. However, in this case, the total volume of the battery pack is inevitably increased so as to fix the space outside the housing member corresponding to the refrigerant outlet. As a result, the above structure is not preferred.

  Preferably, the refrigerant outlet is formed on a side opposite to the refrigerant inlet side so that the refrigerant introduced through the refrigerant inlet can be discharged after the refrigerant has passed through the unit module. . For example, the refrigerant inlet may be formed on one side adjacent to the upper edge of the housing member in the form of a series of through holes, and the refrigerant outlet may be at least one of the lower ends of the housing member. Can be formed on the side. More specifically, when the refrigerant inlet is formed at the upper left end of the housing member, the refrigerant outlet is formed at the lower right end or the opposite lower end so that the refrigerant outlets are parallel to each other. Can. Here, the side part of the housing member in which the refrigerant inlet and the refrigerant outlet are formed can be changed according to the direction in which the battery module is inclined. For example, when both the refrigerant inlet and the refrigerant outlet are formed on the left side of the housing, the battery module is mounted such that the upper end of the battery module is inclined toward the left side of the housing member.

  Preferably, the cooling fan (blower fan) is attached to the refrigerant outlet in order to generate a driving force necessary for the flow of the refrigerant.

  Preferably, the battery module is inclined at an angle of 1 ° to 40 °. When the inclination angle of the battery module is too small, the size of the refrigerant inlet is reduced, and therefore it is difficult to increase the amount of refrigerant introduced per unit time. On the other hand, if the tilt angle of the battery module is too large, the tilted arrangement of the battery module becomes unstable when undesirable external impact is applied to the battery module. More preferably, the battery module is inclined at an angle of 1.5 ° to 15 °.

  In a preferred embodiment, the battery module is mounted on a frame having a pair of supports that protrude upward while being spaced apart from each other to support the opposite side of the lower end of the battery module, and the housing member is The housing member is coupled to the frame so as to surround some or all of the surfaces of the battery module except for the lower end surface of the battery module to seal the battery module.

  Preferably, the support part protrudes perpendicularly to a direction in which the refrigerant is introduced through the refrigerant inflow port so that the opposite side of the battery module is supported by the support part. In particular, the support part is a direction in which the unit modules are stacked horizontally so as to support the opposite side of the lower end of the unit modules on which the support parts are stacked, while each unit module is vertically upright on one side. It protrudes continuously upward along.

  The frame is formed in a shape that allows the frame to be coupled to the internal structure of the vehicle. For example, when the internal structure of the vehicle forms ridges and valleys to mitigate external impacts applied to the vehicle, the frame support can be fixed to the ridge of the internal structure of the vehicle. The details are disclosed in Patent Document 3 and are submitted under the name of the applicant of the present patent application. The disclosures of the above patent documents are incorporated herein by reference.

  As an example of the method of inclining the housing member and the upper and lower end surfaces of the battery module at a predetermined angle, it is possible to change the protruding height of the support part of the frame so that the support part has a different height It is.

  The above and other objects, features, and other advantages of the present invention will be more clearly understood from the following detailed description in view of the accompanying drawings.

  The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings. However, it should be noted that the scope of the present invention is not limited by the illustrated embodiment.

  FIG. 3 is a perspective view illustrating a battery pack according to a preferred embodiment of the present invention, and FIG. 4 is a front perspective view of FIG.

  Referring to the drawings, a battery pack 100 is a battery module 20 having a structure in which a plurality of unit modules are electrically connected to each other, and the unit modules 10 are stacked in the horizontal direction. 10 has a battery module 20 that stands upright on one side, and a pair of support portions 33 and 34 that protrude upward and are spaced apart from each other to support the opposite side of the lower end of the battery module 20. A housing member 40 having a frame 30, a refrigerant inlet 45 formed at the upper left end thereof, and a refrigerant outlet (not shown) formed at the lower right end thereof parallel to the refrigerant inlet 45; including. The housing member 40 is coupled to the frame 20 so that the housing member 40 surrounds the battery module 20.

  The battery module 20 is inclined toward the refrigerant inlet 45 by a predetermined angle because of the pair of support portions 33 and 34 protruding from the frame 30 at different heights. As a result, the gap formed between the housing member 40 and the upper end surface 21 of the battery module 20 is inclined, and the gap formed between the housing member 40 and the lower end surface 22 of the battery module 20 is inclined, Thereby, the flow path of the refrigerant is naturally formed by the inclination.

  The refrigerant introduced through the refrigerant inflow port flows, for example, along a gap formed between the unit modules 10 arranged in parallel to the direction in which the refrigerant is introduced, along the flow path 26 in the vertical direction. Next, the refrigerant is discharged through a refrigerant discharge port (not shown). As a result, the large fluid resistance that occurs in the structure of FIG. 1 does not occur when refrigerant is introduced into the vertical flow path 26, thus increasing the cooling efficiency of the battery package. As a result, as illustrated in FIG. 3, the refrigerant flows along the vertical flow path with a gentle slope.

  Since the refrigerant inlet 45 is formed at the upper left end of the housing member 40 in parallel with the vertical flow path 26, the refrigerant inlet 45 and the area A of the vertical flow path 26 farthest from the refrigerant inlet 45. Is limited by the length of each unit module 10. As a result, the cooling non-uniformity can be greatly reduced, and this non-uniformity of the refrigerant is related to the refrigerant inlet 45 and the area A of the vertical channel farthest from the refrigerant inlet 45. Caused by increasing the distance between.

  While the preferred embodiment of the present invention has been disclosed for purposes of illustration, those skilled in the art will recognize that various modifications may be made without departing from the scope and spirit of the invention as disclosed in the appended claims. Recognize that additions and replacements are possible.

  As will be apparent from the above description, the battery pack according to the present invention comprises a battery module mounted on a housing member such that the battery pack is tilted at a predetermined angle, thereby providing a naturally tilted flow path. Is formed in a structure formed in a gap formed between the housing member and the upper end surface of the battery module and in a gap formed between the housing member and the lower end surface of the battery module. As a result, the battery pack according to the present invention has a compact structure due to the cooling structure without increasing its height. Further, the gap (vertical flow path) between the unit modules is arranged in parallel to the direction in which the refrigerant is introduced. As a result, the supply of refrigerant to the battery module is efficiently achieved. Furthermore, the distance between the refrigerant inlet and each vertical channel section farthest from the refrigerant inlet is limited by the length of each unit module. As a result, the amount of refrigerant supplied to each compartment of the battery module is uniform, thereby improving the non-uniform cooling of the battery pack. In addition, the battery pack according to the present invention can be improved so that the shape of the lower end frame constituting the battery pack matches the internal structure of the vehicle. As a result, the battery pack according to the present invention is stably attached by the vehicle.

1 is a perspective view of a conventional cooling system. 1 is a perspective view illustrating a battery module according to a preferred embodiment of the present invention. 1 is a perspective view illustrating a battery pack according to a preferred embodiment of the present invention. FIG. 4 is a front perspective view of FIG. 3.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cooling system 2 Battery module 3 Refrigerant inflow port 4 Refrigerant discharge port 5 Unit module 6 Secondary battery 10 Unit module 20 Battery module 21 Upper end surface 22 Lower end surface 26 Vertical flow path 30 Frame 33 Support unit 34 Support unit 40 Housing member 45 Refrigerant inlet

Claims (3)

A medium- or large-sized battery pack having a battery module including a plurality of unit modules,
While a plurality of the unit modules are stacked in the horizontal direction, each of the unit modules are erected in the vertical direction, the battery module is in the sealed middle- or large-sized battery pack is mounted in the space of the housing member,
When the length of each unit module in the longitudinal direction is a, the width of each unit module is b, and the thickness of each unit module is c, the battery module has the following inequality with the width of the battery module: A stack of up to x unit modules so as to satisfy a <c × x, and the refrigerant inlet is formed in the housing member at a position corresponding to the c × x side,
The housing member includes a refrigerant inlet formed at an upper end of one side surface of the housing member in a longitudinal direction of the unit module, and a lower end of at least one side surface of the housing member in a direction in which the unit modules are stacked. And the longitudinal direction of the unit module is orthogonal to the direction in which the unit modules are stacked,
The battery module, upper and lower end surfaces of the battery module, as will be tilted toward the coolant inlet port by a predetermined angle, attached to said housing member, whereby, through pre-Symbol coolant inlet The introduced refrigerant passes through the unit module in the vertical direction and is then discharged to the opposite side,
A gap (vertical flow path) formed between the unit modules at the inclined upper end surface or lower end surface of the battery module is arranged in parallel to the direction in which the refrigerant is introduced ,
The refrigerant inlet is in the form of a plurality of through holes in a row along the direction in which the unit modules are stacked .
The battery module is mounted on a frame having a pair of support portions,
The support portions protrude upward at different heights, while being separated from each other so as to support the opposite side of the lower end of the battery module,
The support portion protrudes perpendicularly to the direction in which the refrigerant is introduced through the refrigerant inlet and the direction from which the refrigerant is discharged from the refrigerant outlet,
The frame is coupled to the housing member to seal the battery module;
The frame is formed in a shape that allows the frame to be coupled to an internal structure of a vehicle, the internal structure of the vehicle including ridges and valleys that mitigate external impacts acting on the vehicle, thereby The support portion of the frame is fixed to the ridge of the internal structure of the vehicle,
The battery pack, wherein the battery module is inclined at an angle of 1 ° to 40 °.   The battery pack according to claim 1, wherein each unit module is a battery cell that can be charged and discharged, or a combination of two or more of the battery cells.   The battery pack according to claim 1, further comprising a cooling fan (blower fan) attached in the refrigerant discharge port to generate a driving force necessary for the flow of the refrigerant.

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