300 forming an upper-lower layer structure by using the coolant flowing in the liquid cooling plates 1. Therefore, compared with the conventional air cooling device, the liquid cooling device 100 can effectively dissipate heat from the plurality of heat generating elements 300 at the same time under a condition of limited space, thereby avoiding the influence of continuous high temperature from affecting the stability and reliability of the motherboard 200 during operation.

The number of the motherboards 200 may be configured as required, for example, two, three, four, or more. The number of the heat generating elements 300 provided on each motherboard 200 may be the same or different, as long as one liquid cooling plate 1 corresponding to one motherboard 200 can be connected in series to another liquid cooling plate 1 corresponding to another motherboard 200 to form the liquid cooling loop. For example, two heat generating elements 300 are provided on each motherboard 200, so that two liquid cooling plates 1 corresponding to one motherboard 200 can be connected to another two liquid cooling plates 1 corresponding to another motherboard 200 in a one-to-one correspondence.

The heat generating element 300 includes, but is not limited to, a central processing unit (CPU), a graphics processing unit (GPU), etc.

In an embodiment, referring to FIGS. 1 to 3, the plurality of liquid cooling plates 1 include a first liquid cooling plate 11, a second liquid cooling plate 12, a third liquid cooling plate 13, and a fourth liquid cooling plate 14. The first liquid cooling plate 11 and the second liquid cooling plate 12 are respectively attached to two heat generating elements 300 located on one motherboard 200. The third liquid cooling plate 13 and the fourth liquid cooling plate 14 are respectively attached to two heat generating elements 300 located on another motherboard 200. The first liquid cooling plate 11 and the third liquid cooling plate 13 are connected in series to form a first liquid cooling loop, the second liquid cooling plate 12 and the fourth liquid cooling plate 14 are connected in series to form a second liquid cooling loop, and the first liquid cooling loop and the second liquid cooling loop are connected in parallel. In this way, when the coolant flows into the first liquid cooling loop and the second liquid cooling loop, the first liquid cooling plate 11, the second liquid cooling plate 12, the third liquid cooling plate 13, and the fourth liquid cooling plate 14 can dissipate the heat from the corresponding heat generating elements 300 in time, so as to cool the four heat generating elements 300 at the same time, thereby avoiding the motherboard 200 from being damaged by high temperature. Since the four liquid cooling plates are connected in series in pairs to form the liquid cooling loop, compared with the solution that a single liquid cooling plate 1 forms a liquid cooling loop, there is no need to provide a separated communication loop for each liquid cooling plate 1 in the liquid cooling device 100, which not only can effectively reduce the space occupied by the pipes in the liquid cooling device 100, but also can fully utilize the cooling capacity of the coolant, so as to avoid resource waste while ensuring the heat dissipation effect.

Referring to FIG. 2, the motherboards 200 includes a first motherboard 201 corresponding to the first liquid cooling plate 11 and a second motherboard 202 corresponding to the third liquid cooling plate 13, and the relative position relationship between the first motherboard 201 and the second motherboard 202 can be configured as required. For example, the second motherboard is located above the first motherboard. Alternatively, the second motherboard 202 is located below the first motherboard 201.

In order to better explain that when the coolant flows into the two liquid cooling plates 1 connected in series, not only the cooling capacity of the coolant can be fully utilized, but also the heat dissipation effect on each heat generating element 300 can be ensured, taking the heat generating element 300 as a CPU as an example in the following. Heat dissipation model simulation data are compared between the liquid cooling loop formed by a single liquid cooling plate 1 and the liquid cooling loop formed by two liquid cooling plates 1 connected in series.

Basic data for performing the model simulation includes: a total CPU power consumption of 350 W, a maximum CPU surface temperature (Tcase max) of 55° C., a CPU core (CPU die) power of 350 W, a CPU core (Core die) size of 23.26×20.58, a CPU core (Core die) heat flux density of 18.27 W/cm², a CPU surface temperature (CPU Tcase) of 49.2° C., and a fluid temperature rise of 1 LPM@40° C. of 4.97° C.

According to the above basic data, the liquid cooling loop composed of a single liquid cooling plate 1 is used to simulate the heat dissipation on a single CPU, and the change of CPU temperature with coolant flow rate is shown in the following table:

Coolant flow rate (LPM)
0.5
0.8
1.0
1.2
1.4
1.6
1.8
2.0
3.0
4.0

Tcase (° C.)
54.0
50.4
49.2
48.4
47.8
47.4
47.1
46.8
46.1
45.7

It can be seen from the above table that the temperature of the CPU decreases as the coolant flow rate increases, and it can be seen from a specification that a temperature specification (Tcase spec) of the surface of the CPU under this working condition is 65° C. It can be seen from the above data that the temperature (Tcase) of the surface of the CPU is less than the temperature specification (Tcase spec) of the surface of the CPU, so that the temperature margin of the coolant is sufficient when the coolant flows into the liquid cooling loop to cool the CPU. Based on this, when the liquid cooling loop composed of a single liquid cooling plate 1 is used to dissipate heat from single CPU, it has a good heat dissipation effect.

According to the above basic data and temperature theoretical calculation, the liquid cooling loop formed by two liquid cooling plates 1 connected in series is used to simulate the synchronous heat dissipation on two CPUs, and a temperature of an upstream liquid cooling plate 1 and a temperature of a downstream liquid cooling plate 1 in the liquid cooling loop are shown in the following table:

Temperature (Tcase)
Temperature
Temperature (Tcase)

of the surface of the
difference ΔT
of the surface of the

Coolant
upstream liquid
of the liquid
downstream liquid

flow rate
cooling plate
cooling plate
cooling plate

0.8 LPM
50.4° C.
6.3° C.
56.7° C.

1.0 LPM
49.2° C.
5.0° C.
54.2° C.

1.2 LPM
48.4° C.
4.2° C.
52.6° C.

1.4 LPM
47.8° C.
3.6° C.
51.4° C.

1.6 LPM
47.4° C.
3.1° C.
50.5° C.

1.8 LPM
47.1° C.
2.8° C.
49.9° C.

2.0 LPM
46.8° C.
2.5° C.
49.3° C.

It can be seen from the above table that, compared with the design solution in which a single liquid cooling loop formed by a single liquid cooling plate 1 cools a single CPU, the design solution in which two liquid cooling plates 1 are connected in series to form the liquid cooling loop for synchronous heat dissipation on two CPUs, the temperatures of the two liquid cooling plates 1 in the series loop will also gradually decrease as the coolant flow rate increases, and the temperature difference between the upstream liquid cooling plate 1 and the downstream liquid cooling plate 1 is gradually decrease as the coolant flow rate increases. In addition, when the temperature specification (Tcase spec) of the surface of the CPU is 65° C., it can be seen from the above data that the temperature (Tcase) of the surface of the upstream cooling plate and the temperature (Tcase) of the surface of the downstream liquid cooling plate are both less than the temperature specification (Tcase spec) of the surface of the CPU. The temperature of the surface of the liquid cooling plate is the same as the temperature of the surface of the CPU. Therefore, when the two liquid cooling plates 1 are connected in series to form the liquid cooling loop for simultaneously dissipating heat from the two heat generating elements 300, the liquid cooling loop can not only ensure a better heat dissipation effect, but also ensure more uniform heat dissipation between the liquid cooling plates 1. Based on this, it can be seen that the design in which the two liquid cooling plates 1 are connected in series to simultaneously cool the two heat generating elements 300 can more fully utilize the cooling capacity of the coolant, which is beneficial to avoiding the waste of resources.

A theoretical calculation formula of temperature includes an energy formula Q=cmΔT, a volume flow formula qv=V/t=m/ρt, and a liquid cooling plate temperature difference formula ΔT=P/ρqvc=0.0143 P/qv. In the energy formula, Q is heat and its unit is J, C is specific heat capacity and its unit is J/kg·° C., m is a mass and its unit is kg, ΔT is a temperature difference and its unit is ° C. In the volume flow formula, qv is a coolant volume flow rate and its unit is m³/s, m is a mass and its unit is kg, ρ is a coolant density and its unit is kg/m³, t is a time and its unit is s. In the liquid cooling plate temperature difference formula, P is a CPU power consumption and its unit is W.

In an embodiment, referring to FIGS. 1 to 4, the liquid cooling device 100 further includes a plurality of series pipes 8 and a plurality of branch pipes 4. Each liquid cooling plate 1 is provided with a water inlet 1a and a water outlet 1b. In the two liquid cooling plates 1 forming one liquid cooling loop, the water inlet 1a of one first liquid cooling plate 1 is in communication with the water outlet 1b of the other liquid cooling plate 1 through one series pipe 8, and the water inlet 1a of the one liquid cooling plate 1 and the water outlet 1b of the other liquid cooling plate 1 are in communication with two branch pipes 4, respectively. In this way, when the coolant flows into the liquid cooling loop, the coolant can flow into the one liquid cooling plate 1 from the water inlet 1a and flow out of the other liquid cooling plate 1 from the water outlet 1b, so that the coolant can absorb the heat from the heat generating element 300 corresponding to the liquid cooling plate 1 in time to cool the heat generating element 300.

In an embodiment, referring to FIG. 2 and FIG. 3, when the coolant flows into the liquid cooling loop, a flow direction of the coolant in the liquid cooling loop can be configured as required. For example, the first motherboard 202 corresponding to the one liquid cooling plate 1 may be located above the second motherboard 201 corresponding to the other liquid cooling plate 1, so that the coolant first cools the upper heat generating element 300 and then cools the lower heat generating element 300. Alternatively, the first motherboard 202 corresponding to the one liquid cooling plate 1 may be located below the second motherboard 201 corresponding to the other liquid cooling plate 1, so that the coolant first cools the lower heat generating element 300 and then cools the upper heat generating element 300.

In an embodiment, the flow direction of the coolant in the plurality of liquid cooling loops may be the same. For example, in the first liquid cooling loop, the coolant flows from the first liquid cooling plate 11 to the third liquid cooling plate 13, and in the second liquid cooling loop, the coolant flows from the second liquid cooling plate 12 to the fourth liquid cooling plate 14. That is, in each liquid cooling loop, the coolant flows from the upper liquid cooling plate 1 to the lower liquid cooling plate 1. In another embodiment, each liquid cooling loop can be configured such that the coolant flows from the lower liquid cooling plate 1 to the upper liquid cooling plate 1.

In an embodiment, the flow direction of the coolant in the plurality of liquid cooling loops may be different. For example, in the first liquid cooling loop, the coolant flows from the first liquid cooling plate 11 to the third liquid cooling plate 13, and in the second liquid cooling loop, the coolant flows from the fourth liquid cooling plate 14 to the second liquid cooling plate 12. That is, in some liquid cooling loops, the coolant flows from the upper liquid cooling plate 1 to the lower liquid cooling plate 1, and in other liquid cooling loops, the coolant flows from the upper liquid cooling plate 1 to the lower liquid cooling plate 1.

In an embodiment, referring to FIG. 1 and FIG. 4, the liquid cooling device 100 further includes a plurality of first connecting joints 3 in communication with a plurality of water ports and a plurality of communication pipes in a one-to-one correspondence. The plurality of water ports include the water outlets 1b and the water inlets 1a, and the plurality of communication pipes include the series pipes 8 and the branch pipes 4.

Referring to FIG. 5, each first connecting joint 3 includes a first connecting portion 31, a first fixing portion 32, and a first pagoda portion 33 that are sequentially connected. The first connecting portion 31 is in communication with the corresponding water port. An outer periphery of the first pagoda portion 33 is provided with at least two conical protrusion structures. The first pagoda portion 33 is in communication with the corresponding communication pipe. The first fixing portion 32 is threadedly connected to a nut, so as to fix the first pagoda portion 33 to the corresponding communication pipe.

In this way, when the communication pipe and the first connecting joint 3 are connected, it is only necessary to rotate the nut to ensure that the water port can be reliably in communication with the corresponding communication pipe, thereby ensuring that the liquid cooling device 100 can effectively dissipate heat from the plurality of heat generating elements 300 at the same time when the coolant flows into the liquid cooling device 100. Since each communication pipe in the liquid cooling device 100 is connected to the corresponding water port through the first connecting joints 3 with the same structure, the flow balance between internal nodes of each liquid cooling loop can be well ensured, so that the coolant can be evenly distributed to each liquid cooling plate 1 and each communication pipe, so that the pressure loss during the flow of the coolant can be reduced, uniformity of heat dissipation can be ensured, and the overall heat dissipation efficiency can be improved. Furthermore, compared with the related art that uses a quick connecting joint to connect the liquid cooling plate 1 and the corresponding communication pipe, using the first connecting joint 3 to connect the communication pipe according the embodiment can not only effectively save the cost, but also effectively save a space occupied by internal connection nodes of the liquid cooling device 100, which is conducive to the miniaturization of the device. In addition, the at least two conical protrusion structures of the first pagoda portion 33 can effectively ensure that the communication pipe is not easy to be separated from the first pagoda portion 33 when the first pagoda portion 33 is in communication with the communication pipe, so that the sealing performance between the first connecting joint 3 and the communication pipe can be effectively ensured, and a connection portion between the first connecting joint 3 and the communication pipe can withstand a certain liquid pressure to avoid leakage.

The number of the conical protrusion structures in the first pagoda portion 33 may be configured as required, for example, two, three or more, and the plurality of conical protrusion structures are arranged along an extending direction of the first pagoda portion 33.

In an embodiment, as shown in FIG. 1 and FIG. 2, each motherboard 200 has a first side S1 and a second side S2. The two liquid cooling plates 1 in one liquid cooling loop includes the first liquid cooling plate 11 and the third liquid cooling plate 13. The at least two motherboards 200 includes the first motherboard 201 corresponding to the first liquid cooling plate 11 and the second motherboard 202 corresponding to the third liquid cooling plate 13. A gap is formed between the first motherboard 201 and the second motherboard 202. and the third liquid cooling plate 13 is provided in the gap. One end of the series pipe 8 is connected the third liquid cooling plate 13, the other end of the series pipe 8 bypasses the first motherboard 201 from the first side S1 and is connected to the first liquid cooling plate 11. An end of the branch pipe 4 connected to the first liquid cooling plate 11, which is away from the first liquid cooling plate 11, bypasses the first motherboard 201 from the first side S1 and extends through the gap to the second side S2. An end of the branch pipe 4 connected to the third liquid cooling plate 13, which is away from the third liquid cooling plate 13, extends through the gap to the second side S2. In this way, the pipes of the liquid cooling loop can be arranged by fully utilizing the gap between the first motherboard 201 and the second motherboard 202, so that the structure of the whole liquid cooling device 100 is more compact, and the pipes of the liquid cooling device 100 can be limited in the liquid cooling device 100, thereby avoiding interference between the pipes and other components of the device.

The first side S1 and the second side S2 may be opposite sides of the motherboard 200, or may be adjacent two sides of the motherboard 200.

In an embodiment, as shown in FIGS. 1 to 3, the liquid cooling device 100 further includes a liquid distributor 7, a liquid supply pipe 71, and a liquid return pipe 72. The two branch pipes 4 of each liquid cooling loop are in communication with the liquid distributor 7. The liquid distributor 7 is provided with a liquid entering port and a liquid return port, the liquid supply pipe 71 is in communication with the liquid entering port, and the liquid return pipe 72 is in communication with the liquid return port. The liquid supply pipe 71 and the liquid return pipe 72 are configured to be connected to a liquid cooling distribution assembly (not shown). In this way, when the liquid cooling distribution assembly delivers the coolant to the liquid distributor 7 through the liquid supply pipe 71, the liquid distributor 7 can distribute the coolant to each liquid cooling loop, so that each liquid cooling loop has the coolant flowing therein, so as to cool the plurality of heat generating elements 300 at the same time, thereby ensuring the cooling effect of the liquid cooling device 100. The high-temperature coolant flowing out from each liquid cooling loop can flow back to the liquid cooling distribution assembly through the liquid distributor 7 and the liquid return pipe 74, thereby completing a flow circulation of the coolant.

In an embodiment, the liquid distributor 7 is provided on the second side S2 of the motherboard