Battery thermal management system with embedded composite cold plate

Abstract

The utility model discloses a battery thermal management system with embedded composite cold plates, which relates to the technical field of cooling systems and comprises a plurality of battery thermal management units, and each battery thermal management unit comprises a battery module and two composite cold plates. Specifically, the battery module comprises a plurality of square lithium batteries, and the plurality of square lithium batteries are horizontally stacked; the two composite cold plates are respectively arranged on two opposite sides of the square lithium battery, one side of each composite cold plate, which is connected with the square lithium battery, is provided with a liquid cooling flow channel and a phase change material cavity, cooling liquid circulates in the liquid cooling flow channels, and the phase change material cavity is provided with a phase change material. The utility model has good leak-proof capability and cooling performance.

Description

Technical Field

[0001] The utility model relates to the technical field of cooling systems, in particular to a battery thermal management system with an embedded composite cold plate. Background Art

[0002] Lithium-ion batteries are currently the preferred energy component for electric vehicles due to their high energy density, long cycle life, and low self-discharge rate. However, the performance of lithium-ion batteries is very sensitive to temperature. Both too high and too low operating temperatures will have an adverse effect on the performance of the battery, and extreme high temperatures may even cause thermal runaway. A large number of research results show that the optimal operating temperature range of lithium-ion batteries is 20-40°C, and the maximum temperature difference should not exceed 5°C. Experimental results show that the maximum temperature of a 25Ah lithium iron phosphate battery during 3C rate discharge under natural cooling conditions at 30°C exceeds 48°C, which exceeds the optimal operating temperature range of lithium. Therefore, designing an efficient battery thermal management system is of great significance for the efficient and safe operation of the battery.

[0003] At present, liquid cooling is the mainstream battery cooling method due to its strong cooling capacity. However, the circulation of the coolant consumes energy, and the temperature difference between the inlet and outlet of the coolant is usually large. Phase change material cooling is a passive cooling mode that does not consume energy and can provide a stable temperature range. However, the heat capacity of the phase change material is limited, and it will lose its thermal management ability after a complete phase change. The composite thermal management mode that combines phase change materials and liquid cooling can combine the advantages of both modes. A large number of studies have shown that the composite thermal management mode can simultaneously control the maximum temperature and the maximum temperature difference within the recommended range, and has significant energy-saving potential compared to a single active mode.

[0004] Most existing composite battery thermal management systems use an external structure in which the phase change material is placed on the outside of the battery cell and the liquid cooling tube is located inside the phase change material. This structure not only has the problem of large volume and mass, but also the phase change material has the risk of leakage and deformation. The embedded liquid-cooled composite cold plate structure encapsulates the phase change material inside the cavity, has good leak-proof ability, and the cooling system as a whole is more compact and lightweight. At the same time, the composite cooling system also requires a suitable control strategy to realize its temperature control and energy-saving potential. Utility Model Content

[0005] In view of the fact that phase change materials of battery thermal management systems in the prior art are prone to leakage and have insufficient cooling performance, the utility model provides a battery thermal management system with an embedded composite cold plate.

[0006] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0007] A battery thermal management system with an embedded composite cold plate, comprising: a plurality of battery thermal management units,

[0008] Each of the battery thermal management units comprises:

[0009] - a battery module, comprising a plurality of square lithium batteries, wherein the plurality of square lithium batteries are stacked horizontally;

[0010] - Two composite cold plates, the two composite cold plates are respectively arranged on opposite sides of the square lithium battery, and one side of the composite cold plate connecting with the square lithium battery has a liquid cooling channel and a phase change material cavity, the liquid cooling channel flows with cooling liquid, and the phase change material cavity is provided with phase change material.

[0011] As described above, the battery thermal management system with an embedded composite cold plate, further, the composite cold plate includes a main shell and a cover plate, the main shell is frame-shaped and the edges of the cover plate are connected to one side of the main shell, the liquid cooling channel is arranged on the inner side of the cover plate, and the liquid cooling channel is respectively provided with a coolant inlet and a coolant outlet on opposite sides of the main shell.

[0012] As described above, the battery thermal management system with an embedded composite cold plate, further, the number of the liquid cooling channels is more than two, and several of the liquid cooling channels are arranged in parallel on the inner side of the composite cold plate to divide the inner space of the composite cold plate into several phase change material cavities.

[0013] As described above, in the battery thermal management system with an embedded composite cold plate, further, the liquid cooling channel is a periodic waving flow shape, and there are more than two complete waving cycles in the length direction of the liquid cooling channel.

[0014] As described above, in the battery thermal management system with an embedded composite cold plate, further, the phase change material is filled in the phase change material cavity, the phase change material is paraffin or paraffin / expanded graphite composite material, and the phase change material cavity is provided with a liquid injection port.

[0015] In the battery thermal management system with an embedded composite cold plate as described above, further, the thickness of the main shell is in the range of 0.5 mm to 4 mm.

[0016] As described above, the battery thermal management system with an embedded composite cold plate, further, the number of the phase change material cavities is more than three, and the thickness of the phase change material cavity ranges from 1mm to 10mm, and the phase change temperature of the phase change material ranges from 30 to 40°C.

[0017] The battery thermal management system with an embedded composite cold plate as described above, further, the cross-sectional shape of the liquid cooling channel includes any one of a circular cross-section, a rectangular cross-section, a triangular cross-section and a diamond cross-section.

[0018] The battery thermal management system with an embedded composite cold plate as described above, further, the flow rate of the coolant in the liquid cooling channel is in the range of 0.05 to 0.2 m / s, and the operating temperature is in the range of 30 to 40° C.,

[0019] The battery thermal management system with an embedded composite cold plate as described above, further, the cross-sectional area of ​​the liquid cooling channel ranges from 5 to 50 mm 2 The cross-sectional area of ​​the circular cross section is 12 to 36 mm 2 .

[0020] Compared with the prior art, the utility model has the following beneficial effects:

[0021] 1. The new embedded composite cold plate provided by the utility model combines passive phase change material cooling and active liquid cooling, and has good cooling performance and temperature uniformity. The phase change material can provide phase change latent heat to alleviate the drastic change of battery temperature, and the liquid cooling flow channel can timely restore the latent heat of the phase change material and assist in reducing the battery temperature.

[0022] 2. The new embedded composite cold plate provided by the utility model encapsulates the phase change material in the phase change material cavity, effectively reducing the probability of phase change material leakage. At the same time, the contact area between the phase change material and the inside of the composite cold plate is large, and has good heat transfer characteristics. At the same time, the detachable cover plate and liquid injection port enable the composite cold plate to clean and replace the built-in phase change material according to actual needs.

[0023] 3. The internal liquid cooling channel of the new embedded composite cold plate provided by the utility model adopts a wavy flow structure. The flow channel shape, number of channels, flow channel cross-sectional shape, and flow channel area parameters are optimized to have both good heat exchange performance and low flow power consumption, which can improve the energy utilization efficiency of the cooling system.

[0024] 4. The new embedded composite cold plate provided by the utility model is made of all-aluminum material. Compared with the traditional composite cooling structure, it has the advantages of compact structure, small size, light weight, high space utilization, etc. It can be used in electric vehicles to improve the overall energy density of the battery cell.

[0025] 5. The new embedded composite cold plate provided by the utility model adopts a method of controlling the operating parameters of the coolant based on the maximum temperature of the battery, the maximum temperature difference and the temperature of the composite cold plate. This control method can provide better temperature uniformity for the battery and reduce the system operating power consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0027] Figure 1 A schematic diagram of the cover plate model structure of an embedded composite cold plate for a square lithium battery provided by the utility model;

[0028] Figure 2 A schematic diagram of the internal structure of a cover plate model structure of an embedded composite cold plate for a square lithium battery provided by the utility model after the cover plate is removed;

[0029] Figure 3 This is a center cross-sectional view in the thickness direction of an embedded composite cold plate for square batteries provided by the utility model;

[0030] Figure 4 This is a schematic diagram of the welding model structure of an embedded composite cold plate for a square battery provided by the utility model;

[0031] Figure 5 A DSC curve diagram of a phase change material used in the utility model;

[0032] Figure 6 A schematic diagram of the three-dimensional structure of a composite battery thermal management system provided by the utility model;

[0033] Figure 7 The present invention provides a flow chart of an operation control method of a composite battery thermal management system.

[0034] In the attached drawings: 1-base; 2-liquid cooling cavity; 3-phase change material cavity; 4-liquid injection port; 5-water channel joint; 6-connection hole; 7-gasket groove; 10-main body shell; 20-cover plate; 21-liquid cooling channel; 22-channel shell; 30-fixing screw; 40-integrated cold plate shell; 50-square lithium battery; 60-composite cold plate; DETAILED DESCRIPTION

[0035] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0036] Example:

[0037] It should be noted that the terms "first", "second", etc. in the specification and claims of the utility model and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the utility model described here can be implemented in an order other than those illustrated or described here. In addition, the terms "including" and "having" in the embodiments of the utility model and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0038] In the description of the present invention, "multiple" means at least two, such as two, three, etc., unless otherwise clearly defined. In addition, unless otherwise clearly defined and defined, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0039] In view of the fact that the phase change materials of the battery thermal management system in the prior art are prone to leakage and have insufficient cooling performance, an embodiment of the utility model provides a battery thermal management system with an embedded composite cold plate, which includes a plurality of battery thermal management units, each of which includes a battery module and two composite cold plates. Specifically, the battery module includes a plurality of square lithium batteries, and the plurality of square lithium batteries are stacked horizontally; the two composite cold plates are respectively arranged on opposite sides of the square lithium batteries, and one side of the composite cold plate and the square lithium battery is connected to a liquid cooling channel and a phase change material cavity, and a coolant flows in the liquid cooling channel to restore the latent heat of the phase change material and cool the battery, and the phase change material cavity is provided with a phase change material to provide a heat buffer, which can suppress the temperature rise of the battery and improve the uniformity of the battery temperature.

[0040] It can be seen that the composite cold plate combines passive phase change material cooling and active liquid cooling, and has good cooling performance and temperature uniformity. The phase change material can provide phase change latent heat to alleviate the drastic changes in battery temperature. The liquid cooling flow channel can promptly restore the latent heat of the phase change material and assist in lowering the battery temperature. Furthermore, the composite cold plate encapsulates the phase change material in the phase change material cavity, effectively reducing the probability of phase change material leakage. At the same time, the phase change material has a large contact area with the inside of the composite cold plate and has good heat transfer characteristics. At the same time, the removable cover and liquid injection port allow the composite cold plate to clean and replace the built-in phase change material according to actual needs.

[0041] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0042] Figure 1 This is a schematic diagram of the cover plate model structure of an embedded composite cold plate for a square lithium battery in an example of the utility model. Figure 2 This is a schematic diagram of the internal structure of the cover plate model of the embedded composite cold plate provided by the utility model after the cover plate is removed. Figure 1 As shown, the main independent components of the embedded composite cold plate include a main shell 10, a cover plate 20, and fixing screws 30. The cover plate 30 is stacked in parallel on the side of the main shell 10 to form a closed cavity structure, and the fixing screws 30 penetrate and fix the main shell 10 and the cover plate 20 to fix the relative positions of the two. The thickness of the main shell 10 ranges from 0.5 mm to 4 mm.

[0043] In one embodiment, the main housing 10, the cover plate 20 and the liquid cooling cavity 2 are connected to each other to form a plurality of sealed independent phase change material cavities 3 for accommodating phase change materials. One side of the phase change material cavity 3 is connected to the outside through the liquid injection port 4, and the liquid injection port 4 can be opened or closed as needed to fill or discharge liquid phase change materials.

[0044] In one embodiment, the main shell 10 and the cover plate 20 are made of aluminum in one piece, so as to ensure the sealing and overall mechanical strength of the embedded composite cold plate. The liquid cooling cavity 2 is connected to the inner wall of the main shell 10 by welding, so as to ensure that the phase change material cavity 3 has a stable cavity structure. The gasket groove 7 is used to place a sealing gasket of a size suitable for the gasket, and the sealing of the gasket is enhanced by applying pressure to prevent the liquefied phase change material from leaking from the embedded composite cold plate. In addition, the composite cold plate can also be made of all-aluminum material. Compared with the traditional composite cooling structure, it has the advantages of compact structure, small size, light weight, high space utilization, etc., and can be used in electric vehicles to improve the overall energy density of the battery cell.

[0045] As another preferred embodiment of the above-mentioned embedded composite cold plate, Figure 4 The schematic diagram of the welding model structure of an embedded composite cold plate for a square battery provided by the utility model is that the main shell 10 and the cover plate 20 are welded together into an integrated cold plate shell 40 without the use of fixing screws 30. The integrated cold plate shell enhances the sealing and overall mechanical strength.

[0046] In one embodiment, the liquid cooling housing includes a base 1, a liquid cooling cavity 2, a liquid injection port 4, a water channel joint 5, a connection hole 6 and a gasket groove 7. The main housing 10 has a plurality of liquid cooling cavities 2 connected thereto on the inside thereof, for cooling liquid to flow into the embedded composite cold plate for heat exchange. The main housing 10 is provided with a plurality of water channel joints on the outside thereof for connecting to an external liquid cooling circulation system.

[0047] Specifically, Figure 3 This is a cross-sectional view of the center of the thickness direction of an embedded composite cold plate for a square lithium battery provided by the utility model. Figure 3 As shown, the liquid cooling cavity 2 includes a liquid cooling channel 21 and a channel housing 22. The liquid cooling channel 21 has an inlet and an outlet for the coolant to flow inside the liquid cooling cavity 2. The liquid cooling housing 22 completely covers the liquid cooling channel 21, serving as a medium for heat exchange between the coolant and the embedded composite cold plate, while ensuring that the coolant does not leak.

[0048] The outlets and inlets of the water channel joints 5 correspond to each other in pairs, and the inlets and inlets are located at the same position in the width direction of the cold plate shell. A single embedded composite cold plate includes an even number of the water channel joints 5 .

[0049] In one embodiment, the thickness of the flow channel shell 22 remains unchanged along the flow direction of the coolant, and the liquid cooling flow channel 21 and the flow channel shell 22 remain parallel to ensure uniform heat transfer of the coolant during the flow process.

[0050] In one embodiment, the liquid cooling channel 21 generates periodic fluctuations in the same direction as the width direction of the embedded composite cold plate in the flow direction, which is used to induce the Dean vortex of the fluid, and can enhance the heat transfer capacity of the coolant to the channel housing 22. The periodic fluctuation increases the contact area between the channel housing 22 and the phase change material cavity 3, the main housing 10 and the cover plate 20, and effectively improves the heat exchange efficiency between the coolant and the embedded composite cold plate. The number of fluctuations of the periodic fluctuation is an integer to ensure that the inlet and outlet positions of the liquid cooling channel are aligned.

[0051] In one embodiment, the channel flow shape of the liquid cooling channel 21 is a tangent arc shape, the number of periodic fluctuations is 3, the channel cross-sectional shape is circular, the channel cross-sectional area is 36 mm2, the number of channels is 2, the channel fluctuation amplitude is 9.21 mm, and the phase change material cavity 3 is filled with phase change material, then the above-mentioned embedded composite cold plate is used for the composite battery thermal management system has relatively the best thermal management performance.

[0052] Furthermore, the cooling efficiency of the embedded composite cold plate can be further improved by changing the channel flow shape, channel cross-sectional shape, channel cross-sectional area, channel number and channel fluctuation amplitude of the liquid cooling channel 21; the specific shapes of the channel flow shape include sinusoidal wave flow shape, arc flow shape and broken line flow shape; the specific shapes of the channel cross-sectional shape include circular cross-section, rectangular cross-section, triangular cross-section and diamond cross-section; the channel cross-sectional area ranges from 5 to 50 mm2; the number of channels is at least 1; the channel fluctuation amplitude ranges from 1 to 20 mm. It can be seen that the liquid cooling channel adopts a wave flow structure, and the channel flow shape, channel number, channel cross-sectional shape and channel area parameters are optimized to have both good heat exchange performance and low flow power consumption, which can improve the energy utilization efficiency of the cooling system.

[0053] In one embodiment, the coolant includes water, a water / ethylene glycol mixed solution, a refrigerant, etc. The flow rate of the coolant in the liquid cooling channel ranges from 0.05 to 0.2 m / s, and the operating temperature ranges from 30 to 40°C.

[0054] The phase change material cavity 3 contains paraffin or paraffin / expanded graphite composite phase change material, which uses the latent heat in the phase change process to provide heat buffer to prevent or alleviate drastic changes in battery temperature. Preferably, the number of the phase change material cavities is three or more, and the thickness of the phase change material cavity ranges from 1mm to 10mm, with a preferred thickness of 6mm. Selecting a phase change material within the above thickness range can achieve a better cooling effect.

[0055] The following is a further confirmation of the thermal management effect of the present invention in combination with specific experimental results:

[0056] like Figure 5 As shown, Figure 5 This is a DSC curve of a paraffin phase change material used in the present invention. The curve in the upper half of the figure represents the solidification process, and the curve in the lower half represents the melting process. The phase change material releases heat during the solidification process and absorbs heat during the melting process. Figure 5It can be seen that the initial melting temperature of the phase change material is 36.66°C, the complete melting temperature is 42.21°C, and the melting peak temperature is 39.51°C; the initial solidification temperature of the phase change material is 35.99°C, the complete solidification temperature is 31.64°C, and the solidification peak temperature is 35.08°C. Based on the above-mentioned paraffin phase change material, filling it in the phase change material cavity 3 can improve the heat capacity and temperature uniformity of the embedded composite cold plate, improve the temperature characteristics of the battery, and reduce the operating time of the liquid cooling cycle, which has an energy-saving effect.

[0057] like Figure 6 As shown, Figure 6 This is a schematic diagram of the three-dimensional structure of a composite battery thermal management system provided by the utility model. Two cover-type new embedded composite cold plates 60 with the same specifications and five 25Ah square lithium batteries 50 form a composite battery thermal management system. The square lithium batteries 50 in the composite battery thermal management system are arranged in a horizontal stack, that is, the thickness direction of the square lithium batteries 50 is perpendicular to the horizontal plane. The embedded composite cold plate is in contact with the left and right surfaces of the square lithium battery 50, and the front and back surfaces of the square lithium battery 50 are in contact with each other, which is conducive to reducing the volume and mass of the composite battery thermal management system and improving space utilization. In the composite battery thermal management system, part of the heat generated by the square lithium battery 50 is transferred to the surrounding air through natural convection on the non-contact surface, and the other part is transferred to the phase change material in the phase change material cavity 3 and the coolant inside the liquid cooling cavity 2 through the outer shell of the square lithium battery 50 and the embedded composite cold plate 60.

[0058] In order to provide better temperature uniformity for the battery and reduce the system operating power consumption, this embodiment also provides an operation control method of a composite battery thermal management system, wherein the battery thermal management system also includes a liquid cooling circulation module for regulating the refrigeration power and the water pump power, and the method includes:

[0059] Perform the acquisition operation: obtain the maximum temperature of the battery module and the contact surface temperature of the composite cold plate and the battery module.

[0060] Execute a first judgment operation: determine whether the maximum temperature of the battery module is greater than a preset liquid cooling start temperature, and if so, execute a cooling adjustment operation; if not, execute a second judgment operation;

[0061] Performing a refrigeration adjustment operation: starting a liquid cooling circulation module, obtaining a coolant inlet temperature and a coolant inlet flow rate, and adjusting a refrigeration power and a water pump power of the liquid cooling circulation module according to the coolant inlet temperature and the coolant inlet flow rate, so that the coolant inlet temperature and the coolant inlet flow rate are adjusted to set values, and then performing a second judgment operation;

[0062] Perform a second judgment operation: determine whether the battery module contact surface temperature is lower than the preset liquid cooling shutdown temperature, and determine whether the coolant inlet flow rate is zero; if so, close the liquid cooling circulation module, if not, perform a refrigeration adjustment operation.

[0063] In one embodiment, the steps of obtaining the coolant inlet temperature and the coolant inlet flow rate are as follows:

[0064] Executing the acquisition operation also includes: acquiring the difference between the maximum temperature and the minimum temperature of the battery module;

[0065] Obtaining the coolant inlet temperature according to the difference between the maximum temperature and the minimum temperature of the battery module and the liquid cooling start temperature;

[0066] Obtaining the coolant inlet flow rate according to the liquid cooling start temperature, the contact surface temperature of the composite cold plate and the battery module, and the coolant inlet temperature;

[0067] Wherein, the temperature difference between the coolant inlet temperature and the temperature of the composite cold plate is set to be no less than 1°C.

[0068] In one embodiment, the step of adjusting the cooling power and the water pump power of the liquid cooling circulation module according to the coolant inlet temperature and the coolant inlet flow rate further includes:

[0069] When the coolant inlet temperature is higher than the preset coolant upper limit temperature, or the coolant inlet temperature is lower than the preset coolant lower limit temperature, the cooling power of the liquid cooling circulation module is adjusted according to the coolant upper limit temperature and the coolant lower limit temperature;

[0070] When the coolant inlet flow rate is higher than the preset coolant maximum flow rate, the water pump power of the liquid cooling circulation module is adjusted according to the coolant maximum flow rate.

[0071] In the above embodiment, during the execution of the refrigeration adjustment operation and the shutdown of the liquid cooling circulation module, the acquisition operation is performed at set intervals to dynamically calculate the coolant inlet temperature and the coolant inlet flow rate, and monitor whether to start the liquid cooling circulation module.

[0072] In a specific embodiment, an operation control method of a composite battery thermal management system may include the following process:

[0073] S1: Several temperature observation points are set on the battery surface and the cold plate surface to detect the battery temperature, battery temperature difference and composite cold plate temperature in real time during operation.

[0074] S2: The highest temperature in the monitored battery module is Tb, the difference between the highest and lowest temperatures of the battery module is ΔT, the contact surface temperature of the composite cold plate and the battery module is Tp, and the upper limit temperature of the coolant is T max。Lower limit temperature T of the coolant min ,Maximum flow rate V of the coolant max 。

[0075] S3: Set the liquid cooling start temperature Ts and the liquid cooling stop temperature Te, where Te < Ts;

[0076] S4: When the highest battery temperature exceeds the liquid cooling start temperature Tb > Ts, start the liquid cooling circulation module to make the coolant start to flow. Once the liquid cooling circulation is started, enter S8 for start / stop judgment.

[0077] S5: The coolant inlet temperature Tc is calculated from the battery temperature and the battery temperature difference, Tc = a1·ΔT + Tb - a2, where a1 and a2 are set as constants. It is stipulated that the temperature difference between the coolant inlet temperature and the composite cold plate temperature is not less than 1°C, that is, Tp - Tc ≥ 1°C; if the calculated value of the coolant temperature is higher than the upper limit temperature Tc > T max ,then Tc = T max ;if the calculated value of the coolant temperature is lower than the lower limit value Tc < T min ,then Tc = T min ;

[0078] S6: The coolant inlet flow rate Vc is calculated from the battery temperature and the battery temperature difference; Vc = b·(Tb - Tp) / (Tp - Tc), where b is set as a constant. If the calculated value of the coolant flow rate is higher than the upper limit flow rate Vc > V max ,then Vc = V max ;

[0079] S7: Use the PID regulation method to control the refrigeration power and the water pump power of the liquid cooling circulation module to adjust the coolant inlet temperature Tc and the coolant inlet flow rate Vc to the specified values.

[0080] S8: When the temperature of the composite cold plate is lower than the liquid cooling stop temperature Tp < Te, stop the liquid cooling circulation module to make the coolant stop flowing.

[0081] S9: Collect the temperatures of all observation points in the battery thermal management system every 10 seconds, and calculate the coolant inlet temperature and the inlet flow rate according to the temperature measurement results according to the above calculation method for adjusting the refrigeration power and the water pump power.

[0082] A method for controlling the operating parameters of the coolant by monitoring the highest battery temperature, the maximum temperature difference, and the temperature of the composite cold plate. This control method can provide better temperature uniformity for the battery and reduce the system operating power consumption.

[0083] It should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0084] In the present utility model, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0085] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0086] The above embodiments are only for illustrating the technical concept and features of the utility model, and their purpose is to enable ordinary technicians in the field to understand the content of the utility model and implement it accordingly, and they cannot be used to limit the protection scope of the utility model. Any equivalent changes or modifications made according to the essence of the content of the utility model should be included in the protection scope of the utility model.

Claims

1. A battery thermal management system with an embedded composite cold plate, characterized in that: include: Several battery thermal management units, Each of the battery thermal management units comprises: - a battery module, comprising a plurality of square lithium batteries, wherein the plurality of square lithium batteries are stacked horizontally; - Two composite cold plates, the two composite cold plates are respectively arranged on opposite sides of the square lithium battery, and one side of the composite cold plate connecting with the square lithium battery has a liquid cooling channel and a phase change material cavity, the liquid cooling channel flows with cooling liquid, and the phase change material cavity is provided with phase change material.

2. The battery thermal management system with an embedded composite cold plate according to claim 1, characterized in that: The composite cold plate includes a main shell and a cover plate, the main shell is frame-shaped and the edges of the cover plate are connected to one side of the main shell, the liquid cooling channel is arranged on the inner side of the cover plate, and the liquid cooling channel is respectively provided with a coolant inlet and a coolant outlet on opposite sides of the main shell.

3. The battery thermal management system with an embedded composite cold plate according to claim 1, characterized in that: The number of the liquid cooling channels is more than two, and a plurality of the liquid cooling channels are arranged in parallel on the inner side of the composite cold plate to divide the inner space of the composite cold plate into a plurality of the phase change material cavities.

4. The battery thermal management system with an embedded composite cold plate according to claim 1, characterized in that: The liquid cooling channel is a periodic undulating flow shape, and there are more than two complete undulating cycles in the length direction of the liquid cooling channel.

5. The battery thermal management system with an embedded composite cold plate according to claim 1, characterized in that: The phase change material is filled in the phase change material cavity, the phase change material is paraffin or paraffin / expanded graphite composite material, and the phase change material cavity is provided with a liquid injection port.

6. The battery thermal management system with an embedded composite cold plate according to claim 2, characterized in that: The thickness of the main shell ranges from 0.5 mm to 4 mm.

7. The battery thermal management system with an embedded composite cold plate according to claim 1, characterized in that: The number of the phase change material cavities is more than three, the thickness of the phase change material cavities is in the range of 1 mm to 10 mm, and the phase change temperature of the phase change material is in the range of 30 to 40°C.

8. The battery thermal management system according to claim 1, characterized in that: The specific cross-sectional shape of the liquid-cooling channel includes any one of a circular cross-sectional shape, a rectangular cross-sectional shape, a triangular cross-sectional shape and a diamond cross-sectional shape.

9. The battery thermal management system with an embedded composite cold plate according to claim 1, characterized in that: The flow rate of the coolant in the liquid cooling channel ranges from 0.05 to 0.2 m / s, and the operating temperature ranges from 30 to 40°C.

10. The battery thermal management system with an embedded composite cold plate according to claim 8, characterized in that: The cross-sectional area of ​​the liquid cooling channel ranges from 5 to 50 mm 2 The cross-sectional area of ​​the circular cross section is 12 to 36 mm 2 .

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