Patent Description:
With the increasing development of the power battery, the energy density of batteries is constantly increasing. However, the problem caused by the increase in energy density is the increase in the heat generation amount of the battery, so the requirement for the cooling efficiency of the cooling system of the battery is becoming more and more strict. The power battery can be cooled by water cooling, specifically by installing a cooling system in the battery pack. The cooling system includes a collecting tube and a cooling tube, and the cooling tube is connected with the collecting tube to realize the communication between the flow channels of the two tubes, so that the cooling liquid can circulate in the flow channels of the two tubes, so as to realize the cooling of the battery pack.

At present, when the existing collecting tube is connected with the cooling tube, it is necessary to punch a flanging hole in the collecting tube, and the cooling tube is provided with a necking structure. A step is formed at the necking structure and goes deeply into the flanging hole. A stamping operation is performed on a partial region of the collecting tube, and the stamped portion will protrude from the rest part in the vicinity to form a flanging hole. The end of the flanging hole abuts against the step of the necking structure, and the necking structure is welded to the flanging hole, thereby realizing the connection between the collecting tube and the cooling tube. However, when the cooling tube is provided with a necking structure, the cooling tube needs to be processed by the necking processing equipment, which reduces the production efficiency of the cooling tube and the cooling system. At the same time, the flow resistance of the cooling liquid at the necking structure of the cooling tube increases, which leads to an increase in the energy consumption of the water pump of the cooling system and reduces the energy utilization rate of the cooling system.

<CIT> concerns heat exchanger, particularly for the thermal regulation of an energy-reserve unit, and assembly formed of said exchanger and of said unit.

<CIT> concerns heat exchangers and, more particularly, to an improved connection between a header and a heat transfer tube in a heat exchanger.

<CIT> concerns heat exchanger with header box.

In view of this, embodiments of the present application provide a battery pack and a cooling system thereof to solve the problem of low production efficiency and low energy utilization rate of the cooling system in the prior art. Embodiments of the present application provide a cooling system for a battery pack, the cooling system according to any of claims <NUM>- <NUM> including:.

In the present application, by providing a limiting boss in the mounting hole of the collecting tube, the cooling tube can abut against the limiting boss, so as to limit the cooling tube in the width direction, realize the connection between the cooling tube and the two collecting tubes, and can limit the depth of the cooling tube entering into the mounting hole through the limit boss. At the same time, after the limiting boss is disposed in the collecting tube, there is no need to dispose a necking structure on the cooling tube, which can improve the production efficiency of the cooling system, can avoid the increase of the flow resistance of the cooling liquid caused by the cooling tube being disposed with the necking structure, and can improve the energy utilization rate of the cooling system.

In other aspect, embodiments of the present application further provide a battery pack according to claim <NUM>, including: a battery module including a plurality of unit cells; the cooling system according to the above embodiments; the cooling tube is arranged under the battery module, and a bottom of the battery module and the cooling tube are in contact with each other; wherein the cooling system is configured for cooling the battery module.

In order to explain the technical solutions of embodiments of the present application more clearly, the drawings needed in the embodiments will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application. For the skilled person in the art, without inventive work, other drawings can be obtained from these drawings.

In the drawings, the drawings may not be drawn according to actual scale.

In order to better understand the technical solutions of the present application, embodiments of the present application will be described in detail below with reference to the accompanying drawings.

It should be clear that the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments.

The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms of "a", "said" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

It should be understood that the term "and/or" used in this text is only an associated relationship describing associated objects, indicating that there can be three types of relationships. For example, A and/or B can mean three cases: A alone exists, both A and B exist at the same time and B alone exists. In addition, the character "/" in this text generally indicates that the associated objects before and after are in an "or" relationship.

It should be noted that the "upper", "lower", "left", "right" and other directional words described in the embodiments of the present application are described from the angle shown in the drawings, and should not be construed to limit the embodiments of the present application. In addition, in the context, it should also be understood that when it is mentioned that an element is connected "on" or "under" another element, it can not only be directly connected "on" or "under" the other element, but also it is indirectly connected "on" or "under" another element through an intermediate element.

Refers to <FIG>, in which <FIG> is a partial structural diagram of the battery pack provided by the present application in a specific embodiment; <FIG> is a structural diagram of the cooling system in <FIG>; <FIG> is a partial enlarged view of part I in <FIG>; <FIG> is a schematic structural diagram of the blocking cover in <FIG>; <FIG> is a top view of <FIG>; <FIG> is a cross-sectional view taken along the line AA in <FIG>; <FIG> is a partial enlarged view of part II in <FIG>; <FIG> is a schematic diagram of the structure of the collecting tube in <FIG>; <FIG> is a front view of <FIG>; <FIG> is a cross-sectional view taken along the line BB of <FIG>; <FIG> is a partial enlarged view of part III in <FIG>.

Embodiments of the present application provide a battery pack and a cooling system thereof. As shown in <FIG>, the battery pack includes a plurality of battery modules <NUM> stacked along its length direction L, and the battery module <NUM> includes a plurality of unit cells. The stacking direction of the battery module <NUM> is defined as the length direction L of the battery pack. At the same time, the battery pack also includes a casing (not shown in the figure), and each battery module <NUM> is located in the inner cavity of the casing. When the battery pack is operating, the unit cells in the battery module <NUM> generate heat. In order to ensure that the battery pack works at a suitable temperature, a cooling system is provided in the casing of the battery pack in the present application. The cooling system is used to cool each battery module <NUM> in the battery pack.

In an embodiment, as shown in <FIG>, the cooling system includes a plurality of cooling tubes <NUM> along the length direction L of the battery pack. The cooling tubes <NUM> are parallel to each other and extend along the width direction W of the battery pack. The axial direction of the cooling tubes <NUM> is the width direction W of the battery pack. The width direction W of the battery pack is perpendicular to the length direction L. The cooling tube <NUM> may be a harmonica-shaped tube, that is, as shown in <FIG>, the outside of the harmonica-shaped tube has a flat structure, and the inside of the harmonica-shaped tube has a plurality of passages distributed along the length direction L at intervals. The cooling tubes <NUM> are located below the battery module <NUM>, and the bottom of the battery module <NUM> is connected with the flat cooling tubes <NUM> so that the bottom of the battery module <NUM> can exchange heat with the cooling tube <NUM>.

In an embodiment, the cooling system further includes two collecting tubes <NUM>. The two collecting tubes <NUM> are located at the two ends of the cooling tube <NUM> in the width direction W, respectively. The collecting tube <NUM> has a cooling flow channel <NUM> extending in the length direction L inside. The cooling flow channel <NUM> is used for cooling liquid to circulate. After the above-mentioned cooling tube <NUM> is connected to the collecting tube <NUM>, the tube of the cooling tube <NUM> communicates with the cooling flow channel <NUM>. One of the two collecting tubes <NUM> is provided with a liquid inlet <NUM> and a liquid outlet <NUM>.

When the cooling system is operating, the cooling liquid enters the cooling flow channel <NUM> through the liquid inlet <NUM> and enters the cooling tubes <NUM> while flowing along the cooling flow channel <NUM>. The cooling liquid can cool the bottom of the unit cell while flowing in the cooling tube <NUM>, and the circulated cooling liquid is discharged out of the cooling system through the liquid outlet <NUM>.

In the present application, the connection between the collecting tube <NUM> and the cooling tube <NUM> is mainly achieved by improving the structure of the collecting tube <NUM>, thereby improving the operation efficiency of the cooling system and increasing the energy utilization rate of the cooling system.

In an embodiment, as shown in <FIG> and <FIG>, the collecting tube <NUM> includes a body portion <NUM>. The body portion <NUM> has a cooling flow channel <NUM>. At the same time, the body portion <NUM> is also provided with a mounting hole <NUM>. The mounting hole <NUM> is used for connecting the collecting tube <NUM> and the cooling tube <NUM>. Along the width direction W of the battery pack, a limiting boss <NUM> is provided inside the mounting hole <NUM>, and the limiting boss <NUM> is used to abut against the cooling tube <NUM>. With the expression "abut against", it is meant that the cooling tube <NUM> abuts against the limiting boss <NUM>. The extending direction of the cooling tube <NUM> is the width direction W of the battery pack.

In the present application, by providing the limiting boss <NUM> in the mounting hole <NUM> of the collecting tube <NUM>, the cooling tube <NUM> can abut against the limiting boss <NUM>, so that the limiting boss <NUM> functions to limit the cooling tube <NUM> along the width direction W and realizes the connection between the cooling tube <NUM> and the two collecting tubes <NUM>, and can limit the depth of the cooling tube <NUM> entering into the mounting hole <NUM> through the limiting boss <NUM>. At the same time, after the limiting boss <NUM> is provided in the collecting tube <NUM>, there is no need to provide a necking structure in the cooling tube <NUM>, which can improve the production efficiency of the cooling system, and can avoid the increase of the flow resistance of the cooling liquid caused by the cooling tube <NUM> being provided with a necking structure and thus help to improve the energy utilization rate of the cooling system. The necking structure means that after the end of the cooling tube <NUM> is processed by the necking process, the opening corresponding to the end is reduced.

In an example, as shown in <FIG>, the mounting hole <NUM> includes a first hole section <NUM> and a second hole section <NUM> along the width direction W (the axial direction of the mounting hole <NUM> is the width direction W), wherein the second hole section <NUM> communicates with the cooling flow channel <NUM> of the body portion <NUM>. As shown in <FIG>, the size of the first hole section <NUM> in the height direction H is greater than the size of the second hole section <NUM> in the height direction H, and the size of the first hole section <NUM> in the length direction L is also greater than that of the second hole section <NUM> in the height direction H, so that the above-mentioned limiting boss <NUM> is formed between the first hole section <NUM> and the second hole section <NUM>. The height direction H and the width direction W are perpendicular to each other. It should be noted that, as shown in <FIG>, in the mounting hole <NUM>, the first hole section <NUM> and the second hole section <NUM> are coaxial. Therefore, the size of the above-mentioned first hole section <NUM> or the second hole section <NUM> along the height direction H refers to the distance from the side wall of the corresponding hole section to the axis of the mounting hole <NUM> along the height direction H. Similarly, the size of the first hole section <NUM> or the second hole section <NUM> along the length direction L refers to the distance from the side wall of the corresponding hole section to the axis of the mounting hole <NUM> along the length direction L.

In the present embodiment, the mounting hole <NUM> for installing the cooling tube <NUM> in the collecting tube <NUM> is a stepped hole, so that the above-mentioned limiting boss <NUM> can be formed on the inner wall of the mounting hole <NUM>. As shown in <FIG>, the mounting section <NUM> of the cooling tube <NUM> protrudes into the first hole section <NUM> of the mounting hole <NUM>, and abuts against the limiting boss <NUM>, and the cooling tube <NUM> communicates with the second hole section <NUM> so that the cooling tube <NUM> communicates with the cooling flow channel <NUM>.

As shown in <FIG>, the inner diameter of the first hole section <NUM> is the same as the outer diameter of the cooling tube <NUM>, or the inner diameter of the first hole section <NUM> is greater than the outer diameter of the cooling tube <NUM>, so that the outer wall of the cooling tube <NUM> is attached to and welded to the inner wall of the first hole section <NUM>, while ensuring the sealing between the two, reducing the possibility of the leakage of the cooling liquid from between the outer wall of the cooling tube <NUM> and the inner wall of the first hole section <NUM> and preventing the cooling tube <NUM> from falling out of the first hole section <NUM> when the battery pack vibrates.

In an embodiment, after the cooling tube <NUM> abuts against the limiting boss <NUM>, the inner wall of the second hole section <NUM> is flush with the inner wall of the cooling tube <NUM>, that is, the inner diameter of the second hole section <NUM> is the same as the inner diameter of the cooling tube <NUM>. In the present embodiment, since the inner wall of the second hole section <NUM> is flush with the inner wall of the cooling tube <NUM> with no stepped surface between the two, the flow resistance to the cooling liquid can be avoided when the cooling liquid flows through, thereby reducing the energy loss when the cooling liquid flows and improving the energy utilization rate of the cooling system. At the same time, it can also improve the stability of the cooling liquid flow, thereby ensuring the uniformity of the cooling effect. It is understandable that the inner wall of the second hole section <NUM> being flush with the inner wall of the cooling tube <NUM> is not exactly level, as long as the inner walls of the two are substantially flush to reduce the flow resistance to the cooling liquid.

In an embodiment, as shown in <FIG>, the first hole section <NUM> of the mounting hole <NUM> has a first side wall 131a. The cooling flow channel <NUM> has a second side wall 111a. The thickness of the first side wall 131a is greater than the thickness of the second side wall 111a. The thickness of the second side wall 111a is the thickness of the body portion <NUM>. In the body portion <NUM>, the wall thickness at the mounting hole <NUM> is greater than the wall thickness at the rest position of the body portion <NUM>. That is, at the mounting hole <NUM>, the strength of the collecting tube <NUM> at the mounting hole <NUM> can be improved by increasing the wall thickness, and thus the connection reliability between the collecting tube <NUM> and the cooling tube <NUM> in the radial direction is improved.

Further, as shown in <FIG>, in the mounting hole <NUM>, the first hole section <NUM> is also connected to a third hole section <NUM>, and the third hole section <NUM> and the second hole section <NUM> are respectively located on the two ends of in the first hole section <NUM> in the axial direction. Along the direction W1 from the third hole section <NUM> to the first hole section <NUM>, the third hole section <NUM> has a tapered structure with a gradually decreasing cross-sectional area.

The cooling tube <NUM> is welded to the collecting tube <NUM> through the mounting hole <NUM>. In an example, the outer wall of the cooling tube <NUM> is welded to the inner wall of the mounting hole <NUM>. In the present embodiment, the third hole section <NUM> with a tapered structure can facilitate welding operations. At the same time, the third hole section <NUM> can also be used to contain solder, thereby effectively improving the connection stability between the cooling tube <NUM> and the collecting tube <NUM>.

In each of the above embodiments, the body portion <NUM> is provided with a protruding portion <NUM> inside. The protruding portion <NUM> protrudes toward the inside of the body portion <NUM> in the width direction W (the axial direction of the cooling tube <NUM>) and the height direction H. The protruding portion <NUM> extends along the length direction L of the collecting tube <NUM> and the protruding portion <NUM> is correspondingly provided with a plurality of mounting holes <NUM> along the length direction L. Each mounting hole <NUM> extends along the width direction W, and each mounting hole <NUM> is used to connect with the corresponding cooling tube <NUM>. In the present embodiment, by providing the protruding portion <NUM> inside the body portion <NUM>, the size of the mounting hole <NUM> in the width direction W can be increased, thereby increasing the length of the engagement between the cooling tube <NUM> and the mounting hole <NUM>, which is beneficial to improving the connection reliability between the two.

In an embodiment, as shown in <FIG>, a circular arc transition exists between the protruding portion <NUM> and the body portion <NUM>, and the outer contour of the protruding portion <NUM> is a circular arc. Since the protruding portion <NUM> participates in enclosing the cooling flow channel <NUM> of the collecting tube <NUM>, the arrangement of the present embodiment can prevent the cooling flow channel <NUM> from forming a bent position, thereby reducing the flow resistance of the cooling liquid in the cooling flow channel <NUM>, increasing the energy utilization rate of the cooling system, and improving the uniformity of the cooling liquid flowing in the cooling flow channel <NUM>, thereby improving the uniformity of the cooling effect of the cooling system for the battery module <NUM>.

Further, as shown in <FIG>, along the height direction H of the collecting tube <NUM>, the body portion <NUM> has a first bottom wall <NUM> and a second side wall 111a. The second side wall 111a is a side wall close to the cooling tube <NUM>. The protruding portion <NUM> is disposed on the first bottom wall <NUM> and the second side wall 111a, and is located inside the body portion <NUM>. The protruding portion <NUM> protrudes from the first bottom wall <NUM> and the second side wall 111a.

In the present embodiment, when the collecting tube <NUM> is molded, the mounting hole <NUM> is disposed in the protruding portion <NUM> in the body portion <NUM> by machining, without adopting the processing manner of punching the mounting hole via a die in the prior art. Therefore, there is no need to reserve the wall thickness of the punching die in the collecting tube <NUM>, so that the height of the mounting hole <NUM> can be reduced. At the same time, the collecting tube <NUM> in the present application can be directly molded by extrusion, thereby improving the production efficiency of the collecting tube <NUM>, and making the chamfer at the bottom of the collecting tube <NUM> smaller or omitted, so as to enable further reduction of the height of the mounting hole <NUM>. In this way, compared with the prior art, the mounting hole <NUM> in the present application is closer to the bottom of the battery pack, so that the cooling tube <NUM> is closer to the bottom of the battery pack, that is, the height of the entire cooling system in the battery pack can be reduced, and the energy density and group efficiency of the battery pack is improved.

In each of the above embodiments, as shown in <FIG>, along the length direction L of the collecting tube <NUM>, the two ends of the body portion <NUM> are provided with blocking covers <NUM>. The blocking cover <NUM> is used to block the cooling flow channel <NUM> along the length direction L, so as to prevent the cooling liquid from leaking from the end of the collecting tube <NUM>.

In an embodiment, as shown in <FIG>, the blocking cover <NUM> includes a third side wall <NUM> and a second bottom wall <NUM>, wherein the third side wall <NUM> is engaged with and welded to the inner wall of the body portion <NUM>. The second bottom wall <NUM> can block the cooling flow channel <NUM>. The third side wall <NUM> is provided with an inner concave portion <NUM> that engages with the protruding portion <NUM>. The inner concave portion <NUM> is recessed toward the inside of the blocking cover <NUM>, and the inner concave portion <NUM> is attached to and welded to the protruding portion <NUM>.

Of course, the structure of the blocking cover <NUM> is not limited to this, and may be other structures. For example, the blocking cover <NUM> may be a flat plate structure, and the flat plate structure is attached to and welded to each of the two ends of the body portion <NUM> along the length direction L. In the present embodiment, the welding area between the blocking cover <NUM> and the body portion <NUM> is relatively large, which can improve the reliability of the connection between the two and prevent the blocking cover <NUM> from being disconnected from the body portion <NUM> under the action of hydraulic pressure.

In each of the above embodiments, as shown in <FIG>, along the width direction W (the axial direction of the cooling tube <NUM>), the cooling tube <NUM> includes a mounting section <NUM> and a cooling section <NUM>. The mounting section <NUM> protrudes into the mounting hole <NUM>, and the end of the mounting section <NUM> abuts against the limiting boss <NUM>. The cooling section <NUM> is located outside the mounting hole <NUM>. In an example, the cross-sectional area of the mounting section <NUM> is equal to the cross-sectional area of the cooling section <NUM>. The cross-sectional area of the mounting section <NUM> and the cross-sectional area of the cooling section <NUM> being equal does not require exact equality in a mathematic sense, as long as the cross-sectional areas of the two are approximately equal. For example, the cooling tube <NUM> can be an equal-diameter tube, that is, the outer diameters of the cross sections perpendicular to the axial direction at various positions on the cooling tube <NUM> are equal in size.

In the present application, after the above-mentioned limiting boss <NUM> is provided in the mounting hole <NUM> of the collecting tube <NUM>, the cooling tube <NUM> can abut against the limiting boss <NUM>, and therefore, there is no need to install the necking structure in the prior art on the cooling tube <NUM>. That is, the mounting section <NUM> of the cooling tube <NUM> has the same cross-sectional area as the cooling section <NUM>, which can reduce the processing difficulty of the cooling tube <NUM>, improve production efficiency, and prevent increase in the flow resistance of the cooling liquid caused by disposing the necking structure, and improves the energy utilization rate of the cooling system.

Claim 1:
A cooling system for a battery pack, comprising:
a collecting tube (<NUM>) comprising a body portion (<NUM>) with a cooling flow channel (<NUM>);
a cooling tube (<NUM>), wherein said collecting tube (<NUM>) is installed at each of the two ends along the axial direction of the cooling tube (<NUM>), and said cooling tubes (<NUM>) are connected to the cooling flow channel (<NUM>),
wherein the body portion (<NUM>) is further provided with a mounting hole (<NUM>), a limiting boss (<NUM>) is arranged inside the mounting hole (<NUM>), the limiting boss (<NUM>) abuts against the cooling tube (<NUM>) along a width direction, and the axial direction of the cooling tube (<NUM>) is the width direction,
wherein along the width direction, the mounting hole (<NUM>) comprises a first hole section (<NUM>) and a second hole section (<NUM>), the first hole section (<NUM>) is connected to the second hole section (<NUM>), and the second hole section (<NUM>) is connected to the cooling flow channel (<NUM>);
along a height direction and a length direction, a size of the first hole section (<NUM>) is larger than a size of the second hole section (<NUM>), the limiting boss (<NUM>) is formed between the first hole section (<NUM>) and the second hole section (<NUM>), the height direction is the direction in which the collecting tube (<NUM>) extends and is perpendicular to the axial direction, and the width direction, the length direction, and the height direction are perpendicular to each other;
and
the first hole section (<NUM>) has a first side wall (131a), and the body portion (<NUM>) has a second side wall (111a); a thickness of the first side wall (131a) is greater than a thickness of the second side wall (111a).