Patent Description:
Heating units will inevitably produce heat during use. The temperature difference between a plurality of heating units significantly affects the service life of the heating units. In the prior art, air cooling, liquid cooling, or a combination of air cooling and liquid cooling is used to dissipate heat from the heating units. However, both air cooling and liquid cooling lead to inconsistent heat dissipation efficiency amongst the heating units because the heating units are arranged at different positions, resulting in a relatively large temperature difference between the heating units, namely, a poor temperature uniformity. When multiple heating units are used together, such a temperature difference will cause the heating units to have different service lives, which increases difficulties in maintenance. Particularly for a heat dissipation with liquid cooling, cooling liquids flowing through heating units have different flow rates and distinct flow resistances, as a result, the flow paths and the heat dissipation efficiency of the heating units are significantly different. A heating unit with high flow resistance (long pipeline path and small pipeline diameter) has a low flow rate and a low heat dissipation efficiency, while a heating unit with low flow resistance has a high flow rate and a high heat dissipation efficiency.

European Patent Application <CIT> discloses a liquid cooling device for cooling at least one target component.

The objective of the present disclosure is to overcome the above-mentioned defects or problems existing in the background and provides a liquid cooling system and an energy storage system, where a plurality of heating units have the same liquid passage length, so that the flow rates of the cooling liquids flowing through the heating units are consistent, thereby improving the temperature uniformity of the heating units.

In order to achieve the above objective, the following technical solutions are adopted:.

The first technical solution relates to a liquid cooling system, which is used for cooling a plurality of heating units each having an identical cooling flow channel. The cooling flow channel is provided with a liquid inlet and a liquid outlet. The liquid cooling system includes: a cooling liquid circulating supply device provided with a liquid supply port and a liquid return port; and a pipeline system including a liquid supply pipe, a liquid return pipe, and a flow distribution subsystem. One end of the liquid supply pipe communicates with the liquid supply port, and the other end is connected to the flow distribution subsystem at a total flow distribution end located in a first plane. One end of the liquid return pipe communicates with the liquid return port, and the other end is connected to the flow distribution subsystem at a total liquid collection end located on a second plane parallel to, and above, the first plane. The flow distribution subsystem, comprises a liquid distribution pipe located in the first plane and a liquid collection pipe located in the second plane, connects the total flow distribution end and the liquid inlet of each heating unit and connects the total liquid collection end and the liquid outlet of each heating unit. In the flow distribution subsystem, the plurality of heating units have the same liquid passage length. The liquid passage length of the heating unit is equal to the sum of the length of pipeline between the liquid inlet of the heating unit and the total flow distribution end and the length of pipeline between the liquid outlet of the heating unit and the total liquid collection end. The plurality of heating units are located between the first plane and the second plane.

The second technical solution is based on the first technical solution. The flow distribution subsystem includes a first pipeline connecting the liquid inlet of each heating unit and the total flow distribution end and a second pipeline connecting the liquid outlet of each heating unit and the total liquid collection end. The first pipeline is only composed of the liquid distribution pipe located in the first plane, liquid distribution branch pipes extending along a first direction perpendicular to the first plane, and liquid inlet pipes. The liquid distribution pipe communicates with the total flow distribution end. The liquid distribution branch pipes are connected, in parallel, to the liquid distribution pipe, the liquid inlet pipes are connected, in parallel, to the liquid distribution branch pipe, and the liquid inlet pipes are arranged to correspond to the liquid inlets. The second pipeline is only composed of the liquid collection pipe located in the second plane, liquid collection branch pipes extending along the first direction, and liquid outlet pipes. The liquid collection pipe communicates with the total liquid collection end. The liquid collection branch pipes are connected, in parallel, to the liquid collection pipe, the liquid outlet pipes are connected, in parallel, to the liquid collection branch pipe, and the liquid outlet pipes are arranged to correspond to the liquid outlets.

The third technical solution is based on the second technical solution. At least a part of each heating unit is arranged along the first direction, and at least a part of each heating unit is arranged along a second direction. The second direction is parallel to the first plane and the second plane and perpendicular to the first direction. At least a part of the each liquid distribution branch pipe is arranged along the second direction, and at least a part of each liquid collection branch pipe is arranged along the second direction.

The fourth technical solution is based on the third technical solution. At least a part of the each heating unit is further arranged along a third direction. The third direction is perpendicular to the first direction and the second direction. At least a part of each liquid distribution branch pipe is further arranged along the third direction, and at least a part of each liquid collection branch pipe is further arranged along the third direction.

The fifth technical solution is based on the fourth technical solution. The first direction is the vertical direction.

The sixth technical solution is based on the fifth technical solution. The liquid supply port and the liquid return port are located in a third plane perpendicular to the first direction. The third plane is located between the first plane and the second plane or at the same level as the first plane.

The seventh technical solution is based on the sixth technical solution. Each of the heating units extends along the third direction. The liquid inlet and the liquid outlet of the cooling flow channel are located at an end of the heating unit along the third direction. The heating units are arranged along the third direction to form two rows of heating assemblies, each row of heating assemblies is formed by a plurality of heating clusters arranged along the second direction, and each heating cluster is formed by a plurality of heating units arranged along the first direction. The liquid inlet and the liquid outlet of each heating unit in each row of heating assemblies have an extension direction opposite to that of the liquid inlet and the liquid outlet of each heating unit in the other row of heating assemblies. The liquid distribution branch pipes and the heating clusters are arranged in a one-to-one correspondence. The liquid collection branch pipes and the heating clusters are arranged in a one-to-one correspondence.

The eighth technical solution is based on the seventh technical solution. The cooling liquid circulating supply device is located on one side of the pipeline system along the second direction. The total flow distribution end and the total liquid collection end are respectively located at two ends of the pipeline system along the second direction. The liquid distribution pipe only includes a first segment, a second segment, and a third segment. The first segment and the third segment are parallel to each other and both extend in the second direction. The liquid distribution branch pipes are connected, in parallel, to the first segment and the third segment. The second segment extends along the third direction. Two ends of the second segment respectively communicates with the first segment and the third segment, and the second segment intersects with the liquid supply pipe at the total flow distribution end. The liquid collection pipe only includes a fourth segment, a fifth segment, and a sixth segment. The fourth segment and the sixth segment are parallel to each other and both extend in the second direction. The liquid collection branch pipes are connected, in parallel, to the fourth segment and the sixth segment. The fifth segment extends along the third direction. Two ends of the fifth segment respectively communicates with the fourth segment and the sixth segment, and the fifth segment intersects with the liquid return pipe at the total liquid collection end. The liquid return pipe includes a first connection segment extending along the second direction, a second connection segment extending along the first direction, and a third connection segment. One end of the first connection segment intersects with the fifth segment at the total liquid collection end, and the other end communicates with the top end of the second connection segment. The bottom end of the second connection segment communicates with the third connection segment. The other end of the third connection segment communicates with the liquid return port. The first connection segment is provided with an exhaust valve away from the total liquid collection end.

The ninth technical solution is based on the eighth technical solution. The liquid distribution branch pipe and the liquid collection branch pipe are located on two sides of a corresponding heating cluster along the second direction, respectively.

The tenth technical solution is based on the first to the ninth technical solutions. An energy storage system uses the liquid cooling system described in any of the first to the ninth technical solutions.

Compared with the prior art, the above technical solutions have the following advantages.

In order to illustrate the technical solutions of the embodiments more clearly, the accompanying drawings that need to be used are briefly introduced below.

Description of main reference signs: liquid cooling system <NUM>; heating unit <NUM>; liquid inlet <NUM>; liquid outlet <NUM>; cooling liquid circulating supply device <NUM>; liquid supply port <NUM>; liquid return port <NUM>; liquid supply pipe <NUM>; liquid return pipe <NUM>; first connection segment <NUM>; exhaust valve <NUM>; second connection segment <NUM>; third connection segment <NUM>; flow distribution subsystem <NUM>; total flow distribution end <NUM>; total liquid collection end <NUM>; liquid distribution pipe <NUM>; first segment <NUM>; second segment <NUM>; third segment <NUM>; the liquid distribution branch pipe <NUM>; liquid inlet pipe <NUM>; liquid collection pipe <NUM>; fourth segment <NUM>; fifth segment <NUM>; sixth segment <NUM>; liquid collection branch pipe <NUM>; liquid outlet pipe <NUM>; heating assembly <NUM>; heating cluster <NUM>.

In the claims and the specification, unless otherwise defined, the terms "first", "second", or "third", etc. are used to distinguish different objects, rather than to describe a specific order.

In the claims and the specification, unless otherwise defined, orientational or positional relationships indicated by the terms "center", "lateral", "longitudinal", "horizontal", "vertical", "top", "bottom", "inner", "outer", "upper", "lower", "front", "rear", "left", "right", "clockwise", "counterclockwise", etc. are based on the orientational and positional relationships shown in the drawings, which is only for the purpose of simplifying the description and does not imply that the device or element referred to must have a particular orientation or be constructed and operated in a particular orientation.

In the claims and the specification, unless otherwise defined, the term "fixed connection" or "fixedly connected" should be understood in a broad sense, that is, any connection mode without displacement relationship and relative rotation relationship between the two, namely, including non-removably fixed connection, removably fixed connection, integrated connection, and fixed connection by other devices or elements.

In the claims and the specification, unless otherwise defined, the terms "including", "having", and their variants mean "including but not limited to".

The technical solutions in the embodiments will be clearly and completely described below with reference to the accompanying drawings.

Referring to <FIG> show the liquid cooling system <NUM> of the present embodiment, which is used for cooling several heating units <NUM> each having an identical cooling flow channel. The cooling flow channel is provided with the liquid inlet <NUM> and the liquid outlet <NUM>. The liquid cooling system <NUM> includes the cooling liquid circulating supply device <NUM> and a pipeline system.

The cooling liquid circulating supply device <NUM> is provided with the liquid supply port <NUM> and the liquid return port <NUM>. The pipeline system includes the liquid supply pipe <NUM>, the liquid return pipe <NUM>, and the flow distribution subsystem <NUM>. One end of the liquid supply pipe <NUM> communicates with the liquid supply port <NUM>, and the other end communicates with the flow distribution subsystem <NUM> at the total flow distribution end <NUM>. One end of the liquid return pipe <NUM> communicates with the liquid return port <NUM>, and the other end communicates with the flow distribution subsystem <NUM> at the total liquid collection end <NUM>. The flow distribution subsystem <NUM> is used to connect the total flow distribution end <NUM> and the liquid inlet <NUM> of each heating unit <NUM> and connect the total liquid collection end <NUM> and the liquid outlet <NUM> of each heating unit <NUM>. In the flow distribution subsystem <NUM>, the plurality of heating units <NUM> have the same liquid passage length. The liquid passage length of the heating unit <NUM> is equal to the sum of the length of pipeline between the liquid inlet <NUM> of the heating unit <NUM> and the total flow distribution end <NUM> and the length of pipeline between the liquid outlet <NUM> of the heating unit <NUM> and the total liquid collection end <NUM>.

Specifically, at least a part of each heating unit <NUM> is arranged along a first direction, at least a part of each heating unit <NUM> is arranged along a second direction, and at least a part of each heating unit <NUM> is arranged along a third direction, that is, the heating units <NUM> are arranged in a three-dimensional array. The first direction, the second direction, and the third direction are orthogonal. In <FIG> and <FIG>, the first direction is the vertical direction, the second direction is the left-right direction, and the third direction is the front-rear direction. In a specific implementation, each heating unit <NUM> extends along the third direction, and the liquid inlet <NUM> and the liquid outlet <NUM> of the cooling flow channel thereof are located at one end of the heating unit <NUM> along the third direction, in other words, the liquid inlet <NUM> and the liquid outlet <NUM> of the cooling flow channel are located at the front end or the rear end of the heating unit <NUM>. Referring to <FIG>, the liquid inlet <NUM> and the liquid outlet <NUM> of the cooling flow channel are located in the middle of the heating unit <NUM>.

Referring to <FIG>, the heating units <NUM> are arranged along the third direction to form two rows of heating assemblies <NUM>, each row of heating assemblies <NUM> is formed by a plurality of heating clusters <NUM> arranged along the second direction, and each heating cluster <NUM> is formed by a plurality of heating units <NUM> arranged along the first direction. The liquid inlet <NUM> and the liquid outlet <NUM> of each heating unit <NUM> in each row of heating assemblies <NUM> have an extension direction opposite to that of the liquid inlet <NUM> and the liquid outlet <NUM> of each heating unit <NUM> in the other row of heating assemblies <NUM>. In practical applications, the heating units <NUM> can be installed in a rack or a cabinet, the rack or the cabinet is provided with a plurality of installation channels along the vertical direction, and the heating units <NUM> are correspondingly installed in the installation channels. The pipeline system is laid on the rack or the cabinet. In the present embodiment, the each heating unit <NUM> is a battery module with a liquid cooling plate, and the cooling flow channel is arranged in the liquid cooling plate. However, it should be understood that the heating units may also be other electrical modules.

Referring to <FIG>, the cooling liquid circulating supply device <NUM> is provided with the liquid supply port <NUM> and the liquid return port <NUM>. In a specific implementation, the cooling liquid circulating supply device <NUM> is located on one side of the pipeline system along the second direction. In <FIG>, the cooling liquid circulating supply device <NUM> is located on the right side of the pipeline system, and the liquid supply port <NUM> and the liquid return port <NUM> are located in the third plane parallel to the horizontal plane. The design that the liquid supply port <NUM> and the liquid return port <NUM> are located on the same side facilitates the integration of the cooling liquid circulating supply device <NUM>, which is more conducive to transportation and maintenance in practical applications. In the present embodiment, the cooling liquid circulating supply device <NUM> is generally provided with a driving component, such as a circulating pump, to drive the cooling liquid to flow, which belongs to the prior art and will not be repeated in the present embodiment.

In a specific implementation, the total flow distribution end <NUM> is located in the first plane, the total liquid collection end <NUM> is located on the second plane parallel to the first plane, and the heating units <NUM> are located between the first plane and the second plane. The first plane and the second plane are both perpendicular to the first direction, that is, the first plane and the second plane are both horizontal planes. In the present embodiment, the second plane is parallel to and above the first plane, and the third plane is located between the first plane and the second plane. However, it should be understood that the third plane may also be located in the first plane.

In a specific implementation, the flow distribution subsystem <NUM> further includes a first pipeline connecting the liquid inlet <NUM> of each heating unit <NUM> and the total flow distribution end <NUM> and a second pipeline connecting the liquid outlet <NUM> of each heating unit <NUM> and the total liquid collection end <NUM>.

Specifically, the first pipeline is only composed of the liquid distribution pipe <NUM> located in the first plane (that is, the liquid distribution pipe <NUM> is located at the bottom), the liquid distribution branch pipe <NUM> extending along the first direction, and the liquid inlet pipe <NUM>. The liquid distribution pipe <NUM> communicates with the total flow distribution end <NUM>. Liquid distribution branch pipes <NUM> are connected, in parallel, to the liquid distribution pipe <NUM>, liquid inlet pipes <NUM> are connected, in parallel, to the liquid distribution branch pipe <NUM>, and the liquid inlet pipes <NUM> are arranged to correspond to the liquid inlets <NUM>.

In the present embodiment, the liquid distribution pipe <NUM> only includes the first segment <NUM>, the second segment <NUM>, and the third segment <NUM>. The first segment <NUM> and the third segment <NUM> are parallel to each other and both extend in the second direction. The liquid distribution branch pipes <NUM> are connected, in parallel, to the first segment <NUM> and the third segment <NUM>. The second segment <NUM> extends along the third direction. Two ends of the second segment <NUM> respectively communicates with the first segment <NUM> and the third segment <NUM>, and the middle of the second segment <NUM> intersects with the liquid supply pipe <NUM> at the total flow distribution end <NUM>. The liquid distribution pipe <NUM> has a succinct and attractive structure and involves a simple production process, thereby reducing the cost.

At least a part of each liquid distribution branch pipe <NUM> is arranged along the second direction, and at least a part of each liquid distribution branch pipe <NUM> is arranged along the third direction. The liquid distribution branch pipes <NUM> and the heating clusters <NUM> arranged in a one-to-one correspondence. In other words, the way that the liquid distribution branch pipes <NUM> are arranged corresponds to the way that the heating units <NUM> are arranged. In the present embodiment, the liquid distribution branch pipes <NUM> are configured in two rows, with one row at the front end of the front row of heating assemblies <NUM> and the other row at the rear end of the rear row of heating assemblies <NUM>.

In the present embodiment, the lengths of the liquid inlet pipes <NUM> are equal.

The second pipeline is only composed of the liquid collection pipe <NUM> located in the second plane (that is, the liquid collection pipe <NUM> is located at the top), liquid collection branch pipes <NUM> extending along the first direction, and liquid outlet pipes <NUM>. The liquid collection pipe <NUM> communicates with the total liquid collection end <NUM>. The liquid collection branch pipes <NUM> are connected, in parallel, to the liquid collection pipe <NUM>, the liquid outlet pipes <NUM> are connected, in parallel, to the liquid collection branch pipe, and the liquid outlet pipes <NUM> are arranged to correspond to the liquid outlets <NUM>.

Specifically, the liquid collection pipe <NUM> only includes the fourth segment <NUM>, the fifth segment <NUM>, and the sixth segment <NUM>. The fourth segment <NUM> and the sixth segment <NUM> are parallel to each other and both extend in the second direction. The liquid collection branch pipes <NUM> are connected, in parallel, to the fourth segment <NUM> and the sixth segment <NUM>. The fifth segment <NUM> extends along the third direction. Two ends of the fifth segment <NUM> respectively communicates with the fourth segment <NUM> and the sixth segment <NUM>, and the middle of the fifth segment <NUM> intersects with the liquid return pipe <NUM> at the total liquid collection end <NUM>. The liquid collection pipe <NUM> has a succinct and attractive structure and involves a simple production process, thereby reducing the cost. In practical applications, a pipeline located at the top is easily affected by solar radiation and heat rose from a heating unit <NUM> below to have a relatively high temperature, thus the structure design in which the liquid distribution pipe <NUM> is at the bottom and the liquid collection pipe <NUM> is at the top is adopted. The liquid distribution pipe <NUM> communicating with the liquid supply port <NUM> is less affected by solar radiation and the heat rose from the heating unit <NUM> below, which ensures that the cooling liquid flowing into the liquid inlet <NUM> of the heating unit <NUM> has a relatively low temperature, thereby ensuring the heat dissipation efficiency. Furthermore, this structure configuration can also ensure that the cooling flow channel of each heating unit <NUM> is filled with liquid, thereby ensuring the heat dissipation of the heating unit <NUM>. Since the liquid collection pipe <NUM> is located at the top, after the liquid collection branch pipes <NUM> are connected, in parallel, to the liquid collection pipe <NUM>, air bubbles in the liquid flow of each branch will flow upward, thus facilitating the discharge of air bubbles in the pipelines.

At least a part of the each liquid collection branch pipe <NUM> is arranged along the second direction, and at least a part of the each liquid collection branch pipe <NUM> is arranged along the third direction. The liquid collection branch pipes <NUM> and the heating clusters <NUM> are arranged in a one-to-one correspondence. In other words, the way that the liquid collection branch pipes <NUM> are arranged corresponds to the way that the heating units <NUM> are arranged. In the present embodiment, the liquid collection branch pipes <NUM> are configured in two rows, with one row at the front end of the front row of heating assemblies <NUM> and the other row at the rear end of the rear row of heating assemblies <NUM>.

In the present embodiment, the lengths of the liquid outlet pipes <NUM> are equal.

In the present embodiment, the total flow distribution end and the total liquid collection end <NUM> are located at two ends of the pipeline system along the second direction, respectively.

In a specific implementation, the liquid return pipe <NUM> includes the first connection segment <NUM> extending along the second direction, the second connection segment <NUM> extending along the first direction, and the third connection segment <NUM>. One end of the first connection segment <NUM> intersects with the middle of the fifth segment <NUM> at the total liquid collection end <NUM>, and the other end communicates with the top end of the second connection segment <NUM>. The bottom end of the second connection segment <NUM> communicates with the third connection segment <NUM>. The other end of the third connection segment <NUM> communicates with the liquid return port <NUM>. The first connection segment <NUM> is provided with the exhaust valve <NUM> away from the total liquid collection end <NUM>. The liquid return pipe <NUM> has a concise and clear structure and involves a simple production process and a low cost. The exhaust valve <NUM> arranged on the first connection segment <NUM> away from the total liquid collection end <NUM> can discharge the air bubbles of the liquid in each branch, thus further reducing the cost. The arrangement of the second connection segment <NUM> ensures that liquids enter the liquid return port <NUM> after falling down under the action of gravity, thereby reducing the work of a pump.

In the present embodiment, the liquid distribution branch pipe <NUM> and the liquid collection branch pipe <NUM> are located on two sides of the corresponding heating cluster <NUM> along the second direction. This configuration facilitates the connection between the liquid inlet pipe <NUM> and the liquid inlet <NUM> of the heating unit <NUM> and the connection between the liquid outlet pipe <NUM> and the liquid outlet <NUM> of the heating unit <NUM>. Furthermore, compared with the structure where the liquid distribution branch pipe <NUM> and the liquid collection branch pipe <NUM> are located on the same side of the heating cluster <NUM>, this configuration avoids the heat flow between the liquid distribution branch pipe <NUM> and the liquid collection branch pipe <NUM> and is more attractive.

It should be understood that in practical applications, the sizes and quantities of elbows, three-way components, valves, etc. in the pipeline system are the same, and the dimensions of the pipes are the same.

In a specific implementation, the cooling liquid circulating supply device <NUM> provides a liquid flow which flows from the liquid supply port <NUM>, passes through the liquid supply pipe <NUM>, and is distributed at the total flow distribution end <NUM>. A part of the liquid flow passes through the second segment <NUM> of the liquid distribution pipe <NUM> and reaches the first segment <NUM> of the liquid distribution pipe <NUM>. A part of the liquid flow passes through the second segment <NUM> of the liquid distribution pipe <NUM> and reaches the third segment <NUM> of the liquid distribution pipe <NUM>. The liquid flow reaching the first segment <NUM> flows upward to enter the liquid distribution branch pipe <NUM>, passes through the liquid inlet pipe <NUM>, enters the cooling flow channel, and then enters the liquid collection branch pipe <NUM> via the liquid outlet pipe <NUM>. Subsequently, the liquid flow continues to flow upward into the fourth segment <NUM> or the sixth segment <NUM> of the liquid collection pipe <NUM>, passes through the fifth segment <NUM>, and reaches the total liquid collection end <NUM>. Next, the liquid flow enters the first connection segment <NUM> of the liquid return pipe <NUM>, passes through the exhaust valve <NUM>, and reaches the second connection segment <NUM>. Under the action of gravity, the liquid flow flows from the second connection segment <NUM> to the third connection segment <NUM> at the bottom and finally returns to the cooling liquid circulating supply device <NUM> via the liquid return port <NUM>. The above goes in circles.

Therefore, in the present technical solution, the heating units <NUM> have identical cooling flow channel and share the same liquid supply pipe <NUM> and the same liquid return pipe <NUM>, and all the heating units <NUM> in the flow distribution subsystem <NUM> have the same liquid passage length, that is, a liquid flow flowing out from the liquid supply port <NUM> and returning to the liquid return port <NUM> will have substantially the same path length regardless of which heating unit <NUM> the liquid flow passes through. As a result, in practical applications, as long as the pipes are designed to have the same dimension, the liquid flow is allowed to have the same flow rate in the cooling flow channel of each heating unit <NUM>. In other words, the liquid flows in the cooling flow channels of the heating units <NUM> have a uniform flow rate, minimizing the temperature difference of the heating units <NUM>, prolonging the service life of the heating units <NUM>, and reducing the system cost. Specifically, the structures of the first pipeline and the second pipeline are simple and easy for implementation, which is convenient for the laying of the pipeline system and the setting of the heating unit <NUM>. The liquid distribution branch pipe <NUM> extends along the first direction, the liquid collection branch pipe <NUM> extends along the first direction, the liquid distribution pipe <NUM> is located in the first plane, and the liquid collection pipe <NUM> is located in the second plane. The layout is reasonable, concise, and attractive. Moreover, this layout is beneficial to ensure the heating units <NUM> to have the same liquid passage length by adjusting the structures of the liquid collection pipe <NUM> and the liquid distribution pipe <NUM>.

In the present embodiment, the heating unit <NUM> is arranged to correspond to the pipeline system, which facilitates the connection between the liquid inlet pipe <NUM> and the liquid inlet <NUM> of the heating unit <NUM> and the connection between the liquid outlet pipe <NUM> and the liquid outlet <NUM> of the heating unit <NUM>. When the heating unit <NUM> needs maintenance, the heating unit <NUM> can be removed. In addition, this arrangement ensures the heating units to have the same liquid passage length.

The present disclosure also provides an energy storage system (not shown in the figure), which uses the liquid cooling system <NUM> in the above-mentioned embodiments. It is obvious that the temperature difference of the heating units <NUM> in the energy storage system is relatively uniform, which prolongs the service life of the heating units <NUM> and reduces the system cost.

Claim 1:
A liquid cooling system (<NUM>) for cooling a plurality of heating units (<NUM>) each having an identical cooling flow channel provided with a liquid inlet (<NUM>) and a liquid outlet (<NUM>); wherein the liquid cooling system (<NUM>) comprises:
a cooling liquid circulating supply device (<NUM>) provided with a liquid supply port (<NUM>) and a liquid return port (<NUM>); and
a pipeline system including a liquid supply pipe (<NUM>), a liquid return pipe (<NUM>), and a flow distribution subsystem (<NUM>); one end of the liquid supply pipe (<NUM>) communicates with the liquid supply port (<NUM>), and the other end is connected to the flow distribution subsystem (<NUM>) at a total flow distribution end (<NUM>) located in a first plane; one end of the liquid return pipe (<NUM>) communicates with the liquid return port (<NUM>), and the other end is connected to the flow distribution subsystem (<NUM>) at a total liquid collection end (<NUM>) located on a second plane parallel to, and above, the first plane; the flow distribution subsystem (<NUM>), comprises a liquid distribution pipe (<NUM>) located in the first plane and a liquid collection pipe (<NUM>) located in the second plane, connects the total flow distribution end (<NUM>) and the liquid inlet (<NUM>) of each heating unit (<NUM>) and connects the total liquid collection end (<NUM>) and the liquid outlet (<NUM>) of each heating unit (<NUM>); in the flow distribution subsystem (<NUM>), the plurality of heating units (<NUM>) have the same liquid passage length; the liquid passage length of the heating unit (<NUM>) is equal to the sum of the length of pipeline between the liquid inlet (<NUM>) of the heating unit (<NUM>) and the total flow distribution end (<NUM>) and the length of pipeline between the liquid outlet (<NUM>) of the heating unit (<NUM>) and the total liquid collection end (<NUM>), wherein the plurality of heating units (<NUM>) are located between the first plane and the second plane.