A heat spreader with heating and buffering functions and its preparation method and application

Abstract

The present invention relates to a heat spreader with heating and buffering functions, and a preparation method and application thereof. The heat spreader with heating and buffering functions comprises an upper shell, a support unit, a liquid absorbent core unit and a lower shell from top to bottom, the upper shell, the support unit and the lower shell constitute a sealed cavity, the upper shell and the lower shell are connected by the support unit, the support unit comprises a plurality of support columns, and the liquid absorbent core units are arranged in a serpentine shape in the gaps between the support columns of adjacent columns, the bent part of the liquid absorbent core unit is embedded and fixed in the frame of the lower shell, and the two ends of the liquid absorbent core unit penetrate and extend out of the frame and are connected to a power source. The heat spreader shell of the present invention adopts an elastomeric material, so that the heat spreader has the function of buffering and protection, and the liquid absorbent core unit in the heat spreader is a surface-insulated and hydrophilic woven belt structure, which can also be used as a heating wire, so that the heat spreader can achieve rapid heating and heat dissipation of battery cells.

Description

Technical Field

[0001] The present invention relates to the technical field of vapor chamber processing, and in particular to a vapor chamber with heating and buffering functions, and a preparation method and application thereof. Background Art

[0002] Lithium-ion power batteries have a series of problems at high or low temperatures, which greatly limits the improvement of battery performance. Too low temperature will increase the internal resistance of the battery, reduce the discharge amount, reduce the voltage, etc., affecting the vehicle's endurance and power; too high temperature will cause performance degradation and the risk of thermal runaway, affecting the safety of battery use. In addition, lithium-ion power batteries may be subjected to impact or vibration when the car is driving, which may cause the internal components of the battery to shift or compress, resulting in a short circuit, and increase the risk of battery explosion or fire. Therefore, reducing the damage to the power battery caused by impact and maintaining the stability of the battery module are also the main problems currently facing new energy vehicles.

[0003] Prior art CN 117663865 A discloses an anti-expansion ultra-thin heat spreader and a manufacturing method thereof, which relates to the field of heat spreader processing technology, including, from top to bottom, an upper shell, a support unit, a liquid wick unit and a lower shell, wherein the upper shell, the support unit and the lower shell constitute a sealed cavity, the upper shell and the lower shell are connected through the support unit, a liquid wick unit is provided in the gap of the support unit, a steam channel is provided between the liquid wick unit and the support unit, the upper shell is provided with a first liquid injection port connected to the sealed cavity, and the lower shell is provided with a second liquid injection port connected to the sealed cavity. The invention adopts the above structure to effectively solve the expansion and deformation problems under high temperature and vacuum environment, and the obtained heat spreader realizes gas-liquid coplanar-non-planar compound, effectively reduces the interaction and interference of two-phase flow in the phase change process, and the heat transfer performance is less than 10% of the heat transfer performance attenuation of the traditional gas-liquid non-planar heat spreader. However, the heat spreader cannot realize the heating function and has poor buffering performance.

[0004] Prior art CN 215991695 U discloses an ultra-thin heat spreader, which is an ultra-thin closed chamber composed of an upper shell plate, a lower shell plate, an intermediate layer, and a working medium. The intermediate layer is made of porous metal with a steam channel, which can be used as both a liquid wick and a support layer. It fully utilizes the characteristics of the porous metal liquid wick with large capillary suction and high permeability, and because the support layer and support column in the traditional heat spreader structure are eliminated, the thickness of the heat spreader is greatly reduced, and it has excellent heat conduction and heat dissipation effects. However, the heat spreader also cannot achieve the heating function, and the buffering performance is poor.

[0005] Prior art CN 217158348 U discloses a square battery composite thermal management device with anti-collision function, including a box body, a plurality of battery cells are arranged inside the box body, and a heat-conducting gasket is arranged between the plurality of battery cells. A water outlet system is arranged at the lower end of the box body. The difference of this utility model is that the fluid flows in from the middle of the liquid cooling plate and flows out from the middle along the S-shaped channel, thereby improving the thermal inconsistency caused by heat accumulation in the middle of the battery. After the fluid flowing out of the liquid cooling plate enters the main pipeline, it is air-cooled and dissipated by the air flow entering the box body from the outside of the box body. This structure has a dual heat dissipation effect. When the battery is at a low temperature, the system preheats the battery cells by heating the coolant, and at the same time, an "A" type anti-collision plate is installed on the box body because it has sufficient rigidity and sufficient collapse space in the event of a collision, thereby improving the safety of the battery. However, this utility model realizes heating, heat dissipation and protection of the battery by stacking multiple configurations. Although these combined devices can meet the needs of both thermal management and impact protection, their design is complex and the number of parts is increased accordingly, causing the device to occupy more battery space, thereby limiting the energy density of the battery and increasing manufacturing costs. Summary of the invention

[0006] The object of the present invention is to provide a vapor chamber with heating and buffering functions and a preparation method thereof, so as to solve the problems existing in power batteries at high or low temperatures and when subjected to impact.

[0007] In order to achieve the above object, the technical solution of the present invention is as follows:

[0008] A heat spreader with heating and buffering functions comprises, from top to bottom, an upper shell, a support unit, a liquid absorbent core unit and a lower shell, wherein the upper shell, the support unit and the lower shell form a sealed cavity, the upper shell and the lower shell are connected through the support unit, the support unit comprises a plurality of support columns, liquid absorbent core units are arranged in a serpentine shape in the gaps between adjacent columns of the support columns, the bent portion of the liquid absorbent core unit is embedded and fixed in the frame of the lower shell, the two ends of the liquid absorbent core unit pass through and extend outside the frame, and are connected to a power source; the middle section of the liquid absorbent core unit is exposed on the inner surface of the shell; the liquid absorbent core unit is a woven belt made of a plurality of surface-insulated metal wires; the surface-insulated metal wires comprise metal wires and an insulating layer and a porous hydrophilic layer covering the surface of the metal wires from the inside to the outside.

[0009] A steam channel and a liquid working medium are provided between the liquid wick unit and the supporting unit.

[0010] The heat spreader is equipped with a surface-insulated and hydrophilic metal braided belt absorbent core unit and a liquid working medium. The metal braided belt structure with a special structure serves as both an absorbent core and an insulated heating wire. When the battery is at high temperature, the heat spreader absorbs the heat generated by the battery and transfers the heat to heat exchange devices such as liquid cooling or air cooling quickly and evenly through phase change heat transfer, thereby achieving heat dissipation and heat equalization of the battery. When the battery is at low temperature, the metal braided belt absorbent core unit can be energized to generate heat. After the heat spreader absorbs the heat, it quickly heats the battery unit through phase change heat transfer.

[0011] In one of the preferred embodiments, the middle section of the absorbent core unit is perpendicular to the frame in which the bent portion of the absorbent core unit is embedded and fixed.

[0012] The bent portion of the absorbent core unit is embedded and fixed inside the shell frame, and the middle section is exposed on the inner surface of the shell and remains perpendicular to the frame in which the bent portion of the absorbent core unit is embedded and fixed. This fixing method ensures the stability of the shape and position of the absorbent core, prevents deformation or displacement, maintains the integrity and consistency of the capillary structure, and improves the overall capillary performance.

[0013] In one preferred embodiment, the porosity of the porous hydrophilic layer is 10%-40%.

[0014] Too high a porosity will reduce the structural strength and lead to structural instability; too low a porosity will limit the hydrophilic properties and weaken the capillary effect.

[0015] In one preferred embodiment, the resistance of the metal wire is 1.5-3.2 Ω / m.

[0016] If the resistance is too low, the electric heating efficiency will be low; if the resistance is too high, the heat generated when the power is turned on will be too large, which may easily cause the heating wire to burn out.

[0017] In one preferred embodiment, the metal wire is one or more of copper, aluminum, tungsten, molybdenum, stainless steel, nickel-chromium alloy, and silver-nickel alloy.

[0018] In one preferred embodiment, the material of the insulating layer is one or two of polyimide, polyester and polyamide-imide.

[0019] In one preferred embodiment, the method for preparing the insulated metal wire comprises:

[0020] (1) Spraying insulating paint on the surface of the metal wire and curing it to obtain a metal wire with an insulating layer on the surface;

[0021] (2) spraying a composite paint on the metal wire with an insulating layer on the surface, performing secondary curing, and pickling to obtain an insulated metal wire with an insulating layer and a porous hydrophilic layer;

[0022] The composite paint comprises 50-80 parts of insulating paint and 20-50 parts of basic copper carbonate powder.

[0023] If the proportion of basic copper carbonate is too high, the uniformity and adhesion of the coating will be affected; if the proportion of basic copper carbonate is too low, it will be difficult to prepare a porous structure.

[0024] In one preferred embodiment, the thickness of the insulating layer is 0.01-0.03 mm.

[0025] If the thickness is too thin, it is easy to cause electrical breakdown, affecting the safety of the heat spreader. If the thickness is too thick, it is easy to bubble during heating and curing, resulting in unstable insulation layer quality.

[0026] In one preferred embodiment, the thickness of the porous hydrophilic layer is 0.01-0.03 mm.

[0027] If the thickness is too thin, the structure will be unstable and the porous structure will easily fail. If the thickness is too thick, it will be difficult to decompose the powder particles when heated, making it difficult to prepare a porous structure.

[0028] In one preferred embodiment, the preparation method of the composite paint comprises: fully and uniformly mixing the insulating paint and basic copper carbonate powder.

[0029] In one preferred embodiment, the thermal decomposition temperature of the basic copper carbonate powder is lower than 200°C.

[0030] In one preferred embodiment, the diameter of the metal wire is 0.2-0.4 mm.

[0031] If the diameter is too large, the number of metal wires in the liquid wick in the heat spreader will be small, which will reduce the capillary pressure of the liquid wick and affect the heat dissipation performance of the heat spreader; if the diameter is too small, it will be easily burned when powered on for heating, affecting the stability of the heat spreader.

[0032] In one preferred embodiment, the insulating varnish is one or more of polyimide, polyester, and polyamide-imide.

[0033] In one preferred embodiment, the curing temperature in step (1) is 200-220° C. and the curing time is 20-40 min.

[0034] In one preferred embodiment, the secondary curing in step (2) is performed at a temperature of 200-220° C. and for a time of 20-40 min.

[0035] The baking temperature is 200-220 ℃, and the baking time is 20-40 min. If the temperature is too low and the time is too short, the paint will be difficult to fully cure, and if the temperature is less than 200 ℃, the basic copper carbonate particles will be difficult to decompose, and a hydrophilic layer with a sparse pore structure on the surface cannot be prepared; if the temperature is too high and the time is too long, the insulating layer will easily decompose, causing the insulation to fail.

[0036] The basic copper carbonate particles in the insulating varnish decompose into copper oxide, water and carbon dioxide at a baking temperature of 200°C, which makes the insulating film layer have a porous surface structure and makes the surface hydrophilic.

[0037] In one preferred embodiment, the pickling is to rinse the insulated metal wire in an acid solution for multiple times after secondary solidification and cooling to remove residual copper oxide particles.

[0038] In one preferred embodiment, the acid solution is one or more of sulfuric acid, hydrochloric acid, nitric acid, perchloric acid, and permanganic acid.

[0039] In one preferred embodiment, the wick unit is obtained by spirally weaving or arranging a plurality of insulating metal wires in parallel.

[0040] In one preferred embodiment, the wick unit is obtained by spirally weaving or arranging 5 to 15 insulated metal wires in parallel.

[0041] Too many or too few metal wires, or too dense or sparse a wick structure, will cause the capillary pressure generated by the wick to decrease, affecting the heat dissipation performance of the vapor chamber.

[0042] In one preferred embodiment, the upper shell and the lower shell are both made of elastomeric material.

[0043] When a battery collides, the compressible characteristics of the heat spreader shell can reduce the impact force on the battery and protect the battery.

[0044] In one preferred embodiment, the elastomeric material may be one or more of SBS, TPE, and TPEE.

[0045] In one of the preferred embodiments, the absorbent core unit is fixed in the lower shell.

[0046] Based on the same inventive concept, the present invention also claims a method for preparing a vapor chamber having heating and buffering functions, comprising:

[0047] S1, arranging the absorbent core unit in a serpentine shape in a mold, using a metal insert injection molding process, and injecting an elastomer material to form a lower shell with the absorbent core unit and the support unit; during the molding process of the lower shell, the support unit and the shell are integrally molded;

[0048] S2. Splice the lower shell and the upper shell with the liquid wick unit and the support unit and seal them together, then evacuate, inject liquid working medium, and seal to obtain a heat spreader with heating and buffering functions.

[0049] In one preferred embodiment, in step S1, two ends of the wick unit are externally connected to a power source.

[0050] In one of the preferred embodiments, in step S1, the bent portion of the absorbent core unit is embedded and fixed in two frames, with both ends passing through and extending outside the frames, and the middle section is exposed on the inner surface of the shell and remains perpendicular to the two frames in which the bent portion of the absorbent core unit is embedded and fixed.

[0051] In one preferred embodiment, the sealing connection is one of hot pressure welding, hot air welding, high frequency welding, and adhesive bonding.

[0052] In one preferred embodiment, the liquid working medium is one of deionized water, ethanol and acetone.

[0053] Based on the same inventive concept, the present invention also claims protection for a power battery, which includes the above-mentioned heat spreader with heating and buffering functions.

[0054] In one of the preferred embodiments, the heat spreader with heating and buffering functions is arranged between adjacent battery cells.

[0055] The shell and support unit of the heat spreader with heating and buffering functions are made of elastomeric materials. When the battery unit is collided, the heat spreader is deformed by the impact force of the battery unit, thereby playing a buffering role and protecting the battery.

[0056] The present invention provides a heat spreader with heating and buffering functions, which can realize the functions of rapid heating of a battery at low temperatures, rapid heat dissipation at high temperatures, and buffering protection.

[0057] The shell of the heat spreader with heating and buffering functions is made of elastomeric material. The heat spreader is equipped with a surface-insulated and hydrophilic woven belt wick structure and a liquid working medium. The wick unit with a special structure is arranged in the heat spreader, so that it serves as both a wick and a surface-insulated heating wire. When the battery is in low temperature conditions, the wick unit is energized through the power supply at both ends to generate heat. After the heat spreader absorbs the heat, it quickly heats the battery unit through phase change heat transfer; when the battery is under high temperature conditions of charging and discharging, the heat spreader absorbs the heat generated by the battery, and through phase change heat transfer, the heat is quickly and evenly transferred to heat exchange devices such as liquid cooling or air cooling, thereby achieving heat dissipation and heat equalization of the battery. When the battery collides, due to the compressible characteristics of the heat spreader shell, it can reduce the impact force on the battery and protect the battery.

[0058] Compared with the prior art, the present invention has the following beneficial effects:

[0059] (1) The vapor chamber of the present invention adopts phase change heat transfer technology, which can quickly dissipate heat from the battery at high temperatures and quickly heat the battery at low temperatures, ensuring that the overall temperature of the battery remains within a safe range, thereby ensuring the effective operation of the battery and avoiding the risk of rapid battery life decay and fire, explosion, etc.

[0060] (2) The heat spreader shell is made of elastomeric material. When the battery pack is subjected to impact or collision, the stress deformation of the heat spreader can reduce the impact damage to the battery, reduce the risk of battery explosion or fire, and improve the safety of the battery pack.

[0061] (3) The wick unit has been specially treated to insulate the metal wire surface while having good hydrophilicity. The insulation prevents the metal wire from reacting or short-circuiting with the liquid working fluid in the vapor chamber when it is electrified. The hydrophilicity enhances the capillary properties of the wick, ensuring that the vapor chamber can operate efficiently and stably and give full play to its functional role.

[0062] (4) The specially structured liquid wick unit in the vapor chamber serves as both a high-performance liquid wick and a surface-insulated heating wire. This design simplifies the overall structure and enables the vapor chamber to perform multiple functions, effectively saving production costs.

[0063] (5) Only the vapor chamber can realize the bidirectional thermal management of battery heating and heat dissipation as well as the buffer protection function. The integrated design saves space and improves the energy density of the battery pack. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] Figure 1 Schematic diagram of the preparation process of surface-insulated metal wire;

[0065] Figure 2 It is a schematic diagram of the structure of a metal braided liquid-absorbing core;

[0066] Figure 3 Schematic diagram of the structure of the heat spreader;

[0067] Figure 4 is a cross-sectional view of a vapor chamber;

[0068] Figure 5 It is a structural schematic diagram of a power battery system;

[0069] Among them, 1-metal wire; 2-insulating layer; 3-basic copper carbonate particles; 4-porous hydrophilic layer; 5-insulating metal wire; 6-metal braided belt wick structure; 7-support column; 8-lower shell; 9-upper shell; 10-battery unit; 11-heat spreader with heating and buffering functions. DETAILED DESCRIPTION

[0070] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0071] The heat spreader with heating and buffering functions of the present invention comprises an upper shell, a support unit, a liquid wick unit and a lower shell from top to bottom, the upper shell, the support unit and the lower shell constitute a sealed cavity, the upper shell and the lower shell are connected by the support unit, the support unit comprises a plurality of columns of support posts, the liquid wick units are arranged in a serpentine pattern in the gaps between the support posts of adjacent columns, and the two ends of the liquid wick unit are connected to a power source; the liquid wick unit is a metal braided belt prepared from a plurality of surface-insulated metal wires; the surface-insulated metal wires comprise metal wires and an insulating layer and a porous hydrophilic layer coated on the surface of the metal wires from the inside to the outside. The porosity of the porous hydrophilic layer is 10%-40%. A steam channel and a liquid working medium are provided between the liquid wick unit and the support unit. The liquid wick unit is obtained by spirally weaving or arranging 5-15 insulated metal wires in parallel. The materials of the upper shell and the lower shell are both elastomeric materials. The two ends of the liquid wick unit are covered and fixed in the lower shell. The elastomeric material may be one or more of SBS, TPE, and TPEE.

[0072] The heat spreader is equipped with a surface-insulated, hydrophilic, porous metal braided belt absorbent core unit and a liquid working medium. The metal braided belt with a special structure serves as both the absorbent core and the surface-insulated electric heating wire. When the battery is at low temperature, the metal braided belt absorbent core unit can be energized to generate heat. After the heat spreader absorbs the heat, it quickly heats the battery unit through phase change heat transfer. When the battery is at high temperature, the heat spreader absorbs the heat generated by the battery, and through phase change heat transfer, the heat is quickly and evenly transferred to heat exchange devices such as liquid cooling or air cooling, thereby achieving heat dissipation and heat equalization of the battery. When a battery collides, the compressible characteristics of the heat spreader shell can reduce the impact force on the battery and protect the battery.

[0073] The metal wire is one or more of copper, aluminum, tungsten, molybdenum, stainless steel, nickel-chromium alloy, and silver-nickel alloy.

[0074] The material of the insulating layer is one or more of polyimide, polyester and polyamide-imide.

[0075] The thickness of the insulating layer is 0.01-0.03 mm.

[0076] The thickness of the porous hydrophilic layer is 0.01-0.03 mm.

[0077] The preparation method of the insulated metal wire comprises: (1) spraying insulating paint on the surface of the metal wire, curing at 200-220°C for 20-40 min, and obtaining a metal wire with an insulating layer on the surface; (2) spraying a composite paint on the metal wire with an insulating layer on the surface, curing at 200-220°C for 20-40 min, and rinsing the insulated metal wire after the secondary curing and cooling in an acid solution for multiple times to remove residual copper oxide particles, and obtaining an insulated metal wire with an insulating layer and a porous hydrophilic layer;

[0078] The composite paint comprises 50-80 parts of insulating paint and 20-50 parts of basic copper carbonate powder;

[0079] The preparation method of the composite paint comprises the steps of fully and uniformly mixing the insulating paint and basic copper carbonate powder.

[0080] The thermal decomposition temperature of basic copper carbonate powder is lower than 200°C.

[0081] The diameter of the wire is 0.2-0.4 mm.

[0082] The insulating varnish is one or more of polyimide, polyester and polyamide-imide.

[0083] The basic copper carbonate particles in the insulating varnish decompose into copper oxide, water and carbon dioxide at a baking temperature of 200°C, which makes the insulating film layer have a porous surface structure and makes the surface hydrophilic.

[0084] The method for preparing the vapor chamber with heating and buffering functions comprises:

[0085] S1, arranging the absorbent core unit in a serpentine shape in the mold, using a metal insert injection molding process, and injecting an elastomer material to form a lower shell with the absorbent core unit and the support unit. During the molding process of the lower shell, the support unit and the shell are integrally molded;

[0086] The two ends of the absorbent core unit are connected to an external power source. The bent portion of the absorbent core unit is embedded and fixed in the two frames, the two ends penetrate and extend outside the frames, and the middle section is exposed on the inner surface of the shell and remains perpendicular to the two frames where the bent portion of the absorbent core unit is embedded and fixed.

[0087] S2. Splice the lower shell and the upper shell with the liquid wick unit and the support unit and seal them together, then evacuate, inject liquid working medium, and seal to obtain a heat spreader with heating and buffering functions.

[0088] The liquid working medium is one of deionized water, ethanol and acetone. Example 1

[0089] The shell is made of elastomeric material; the liquid-absorbing core is a metal braided belt with an insulating layer and a hydrophilic layer.

[0090] (1) Processing of insulation layer of metal wire

[0091] A fine manganese-copper alloy wire with a resistance value of 1.8 Ω / m and a wire diameter of 0.2 mm is used. A layer of insulating paint is sprayed on the surface of the wire. The insulating paint material is polyimide. The wire is baked and cured at a temperature of 200 °C for 30 min to obtain a wire with an insulating layer on the surface. The preparation process diagram is shown in the figure. Figure 1 As shown, 1 is a metal wire and 2 is an insulating layer.

[0092] (2) Hydrophilic layer processing of metal wire

[0093] Take the prepared metal wire with an insulating layer on the surface, use an insulating paint of the same material as the insulating layer, take 70 parts of insulating paint and 30 parts of basic copper carbonate powder by weight, fully mix and stir the insulating paint and basic copper carbonate particle powder to obtain a composite paint, spray it on the metal wire with an insulating layer on the surface, bake and cure it after spraying, the baking temperature is 205 ° C, the baking time is 30 min, and after baking and curing, the residual copper oxide particles are removed by sulfuric acid solution to obtain a metal wire with an insulating layer and a hydrophilic layer, such as Figure 1 As shown, 3 is basic copper carbonate particles, 4 is a porous hydrophilic layer, and the porosity of the porous hydrophilic layer is 20%.

[0094] (3) Preparation of braided absorbent core

[0095] Take 8 prepared insulated metal wires and spirally weave them into a braided belt structure, such as Figure 2 As shown, 5 is an insulated metal wire and 6 is a metal braided belt absorbent core structure.

[0096] (4) Heat sink shell manufacturing

[0097] Take a braided absorbent core, and use a metal insert injection molding process to arrange the braided absorbent core in a serpentine shape in the mold, and inject the TPEE elastomer material to form a lower shell with an absorbent core and a support column. During the molding process of the lower shell, the support column and the shell are integrally formed, and the bent part of the absorbent core is completely embedded and fixed in the two frames. The two ends pass through and extend out of the frames, and the middle section is exposed on the inner surface of the shell and remains perpendicular to the two frames where the bent part of the absorbent core is embedded and fixed. The outer dimensions of the lower shell of the heat spreader are 600×400×3 mm. An upper shell with a size of 600×400×1 mm is also prepared by injection molding, and the material is the same as that of the lower shell. Figure 3 and Figure 4 As shown, 6 is a metal braided belt absorbent core structure, 7 is a support column, 8 is a lower shell, and 9 is an upper shell.

[0098] (5) Heat sink packaging

[0099] The prepared vapor chamber lower shell and upper shell are spliced ​​and sealed, and then a series of processes such as vacuuming, filling with liquid working medium and sealing are carried out. The liquid working medium filled is deionized water, and the vapor chamber is prepared. Figure 3 As shown, 6 is a metal braided belt absorbent core structure, 7 is a support column, 8 is a lower shell, and 9 is an upper shell.

[0100] (6) Application of heat spreader in battery thermal management and protection

[0101] The heat spreader is arranged between adjacent battery cells. The heat spreader contains liquid working fluid and a woven belt wick structure. The shell of the heat spreader is made of elastomeric material. The overall hardness of the heat spreader is less than the hardness of the battery cell. When the battery cell is collided, the heat spreader is deformed by the impact force of the battery cell, thereby playing a buffering role and protecting the battery.

[0102] Under high temperature conditions, the liquid working medium in the heat spreader changes into steam after being heated in a low vacuum environment. The steam quickly fills the inner cavity of the heat spreader. When the steam contacts the low temperature area of ​​the heat exchange device, it condenses into liquid working medium and releases heat. The condensed liquid working medium flows back to the heat source through the capillary pressure of the wick structure. By repeatedly exchanging heat in the cavity, the heat dissipation and heat equalization of the battery pack are achieved. The metal braided wick structure of the heat spreader is connected to an external power supply. Under low temperature conditions, the current generates heat through the metal wire with a certain resistance in the wick structure, causing the liquid working medium in the heat spreader to change into steam when heated in a low vacuum environment. The steam quickly fills the inside of the heat spreader, and the heat spreads over the entire heat spreader. The heat is quickly and evenly transferred to the battery cells through the heat spreader, thereby achieving heating of the battery at low temperatures. Figure 5 As shown, 10 is a battery unit, and 11 is a heat spreader with heating and buffering functions.

[0103] Comparative Example 1

[0104] The shell is made of metal; the liquid-absorbing core is a metal braided belt with an insulating layer and a hydrophilic layer.

[0105] The heat spreader of comparative example 1 has a shell made of metallic copper, a liquid wick structure that is the same as that of embodiment 1, a heat spreader size that is the same as that of embodiment 1, and other parameters that are the same as those of embodiment 1. The heat spreader of comparative example 1 is compared with the heat spreader of embodiment 1 in terms of function and performance.

[0106] By comparison, it can be found that the heat spreader of comparative example 1 adopts a metal shell and cannot achieve a compressible buffering function. The heat spreader of comparative example 1 cannot achieve a buffering protection function and cannot play a buffering protection role for the battery.

[0107] Comparative Example 2

[0108] The shell is made of metal material; the liquid-absorbing core is a metal braided belt, without an insulating layer and with a hydrophilic layer

[0109] The heat spreader of comparative example 2 has a shell made of metallic copper, wherein the metal braided belt liquid wick has no insulating layer but has a hydrophilic layer. The size of the heat spreader is the same as that in Example 1, and the other parameters are the same as those in Example 1. The heat spreader of comparative example 2 is compared with the heat spreader of Example 1 in terms of function and performance.

[0110] By comparison, it can be found that in terms of function, Comparative Example 2 cannot achieve the heating function. When the metal braided belt is energized, the metal soaking plate will be conductive, which will affect related equipment and create safety hazards. Considering the use and manufacture of the soaking plate, it is necessary to ensure the insulation of the soaking plate, and it is impossible to directly energize and heat the braided belt wick in the soaking plate. In addition, since the metal shell is incompressible, the soaking plate of Comparative Example 2 cannot achieve the function of buffer protection and cannot play a role in buffer protection for the battery.

[0111] Comparative Example 3

[0112] The shell is made of elastomeric material; the liquid-absorbing core is a metal braided belt, without an insulating layer or a hydrophilic layer.

[0113] The heat spreader of comparative example 3 has a shell made of the same elastomeric material as that of example 1, wherein the metal braided belt wick has no insulating layer and hydrophilic layer, the size of the heat spreader is the same as that in example 1, and the rest of the process and parameters are the same as those in example 1. The heat spreader of comparative example 3 is compared with the heat spreader of example 1 in terms of function and performance.

[0114] By comparison, it can be found that in terms of function, comparative example 3 cannot realize the heating function. Considering the use of the heat spreader, it is necessary to ensure the insulation of the heat spreader. Without the insulating layer, the metal braided belt may react with the liquid working fluid in the heat spreader after being energized, or cause a short circuit in the board due to the conductivity of the liquid working fluid, thereby affecting related equipment. Considering the use and manufacture of the heat spreader, it is necessary to ensure the insulation of the heat spreader. Therefore, it is impossible to directly energize and heat the braided belt wick in the heat spreader; in terms of performance, the thermal conductivity of the heat spreader in comparative example 3 is lower than that of the heat spreader in Example 1, because the metal braided belt wick is not as good as the wick with a hydrophilic layer in Example 1, so that the capillary pressure generated by the wick is small, the heat spreader cannot operate efficiently, resulting in poor heat dissipation and heating performance of the heat spreader.

[0115] Comparative Example 4

[0116] The shell is made of elastomeric material; the liquid-absorbing core is a metal braided belt with an insulating layer and no hydrophilic layer

[0117] The heat spreader of comparative example 4 has a shell made of the same elastomeric material as that of example 1, wherein the metal braided belt wick is covered with an insulating layer but has no hydrophilic layer, the size of the heat spreader is the same as that in example 1, and the rest of the process and parameters are the same as those in example 1. The heat spreader of comparative example 4 is compared with the heat spreader of example 1 in terms of function and performance.

[0118] By comparison, it can be found that the thermal conductivity of the vapor chamber in comparative example 4 is lower than that of the vapor chamber in embodiment 1, because the surface of the metal wire in the metal braided belt is smooth after being covered with an insulating layer, and the hydrophilic property is extremely poor, resulting in a small capillary pressure generated by the liquid wick, which causes the vapor chamber to fail to operate efficiently, and the heat dissipation and heat distribution performance of the vapor chamber are poor. In addition, due to the poor heat transfer performance of the vapor chamber, the heating rate of the vapor chamber in comparative example 4 is low.

[0119] Comparative Example 5

[0120] The shell is made of elastomeric material; the liquid-absorbing core is a metal braided belt, without an insulating layer and with a hydrophilic layer

[0121] The heat spreader of comparative example 5 has a shell made of the same elastomeric material as that of example 1, wherein the metal braided belt wick is covered with a hydrophilic layer with a porous structure but has no insulating layer, the size of the heat spreader is the same as that in example 1, and the rest of the process and parameters are the same as those in example 1. The heat spreader of comparative example 5 is compared with the heat spreader of example 1 in terms of function and performance.

[0122] By comparison, it can be found that the heat spreader of Example 5 cannot achieve the function of electric heating. The porous hydrophilic layer covering the metal wire cannot ensure the insulation of the metal wire. When the metal wire is energized, the pores of the porous structure are easily penetrated by the liquid working fluid, resulting in leakage, etc. After the metal braided belt is energized, it may react with the liquid working fluid in the heat spreader or cause a short circuit in the board due to the conductivity of the liquid working fluid. Considering the use and manufacture of the heat spreader, it is necessary to ensure the insulation of the heat spreader. Therefore, it is impossible to directly energize and heat the woven belt liquid absorption core in the heat spreader.

[0123] The heat flow method is used to test the thermal conductivity of the heat spreader. A sample with a thickness of 4 mm and a cross-sectional area of ​​660×510 mm² is clamped between the heating plate and the cooling plate. A heating power of 15,000 W is applied. The temperature difference on both sides of the sample and the heat flow passing through are measured in a steady state, and the thermal conductivity is calculated using the heat flow method formula.

[0124] ;in is the heating power, is the sample thickness, is the cross-sectional area of ​​the sample, is the temperature difference between the two sides of the sample.

[0125] The functions and various performances of the heat spreaders prepared in Example 1 and Comparative Examples 1-5 were compared, wherein the heat dissipation performance was compared by thermal conductivity, and the heating performance was compared by the time it took to heat two battery cells from 0°C to 5°C at a power of 800 W. The results are shown in Table 1.

[0126] Table 1 Comparison of the performance of the vapor chambers prepared in Example 1 and Comparative Examples 1-5

[0127] name Characteristics of Vapor Chamber Thermal conductivity (W / (m·K)) Heating time (s) Buffer protection function Example 1 The shell is made of elastomeric material; the liquid-absorbing core is a metal braided belt with an insulating layer and a hydrophilic layer. 1800 150 have Comparative Example 1 The shell is made of metal; the liquid-absorbing core is a metal braided belt with an insulating layer and a hydrophilic layer. 2500 120 none Comparative Example 2 The shell is made of metal material; the liquid-absorbing core is a metal braided belt, without an insulating layer and with a hydrophilic layer 2500 No heating function none Comparative Example 3 The shell is made of elastomeric material; the liquid-absorbing core is a metal braided belt, without an insulating layer or a hydrophilic layer. 1100 No heating function have Comparative Example 4 The shell is made of elastomeric material; the liquid-absorbing core is a metal braided belt with an insulating layer and no hydrophilic layer 1120 240 have Comparative Example 5 The shell is made of elastomeric material; the liquid-absorbing core is a metal braided belt, without an insulating layer and with a hydrophilic layer 1750 No heating function have

[0128] It can be seen from the table that the metal heat spreader is incompressible and does not have the function of buffering and protection. The metal heat spreader with a liquid wick without an insulating layer, although with a high thermal conductivity, cannot realize the functions of heating and buffering and protection; the elastomer material heat spreader, the liquid wick has no insulating layer and hydrophilic layer, has low thermal conductivity and cannot realize the heating function; the elastomer material heat spreader, the liquid wick has only an insulating layer but no hydrophilic layer, and its thermal conductivity is low, and cannot realize efficient heating and heat dissipation; the elastomer material heat spreader, the liquid wick has a hydrophilic layer but no insulating layer, and considering the leakage during use, the heating function cannot be realized.

[0129] By comparison, it was found that the wick has an elastomeric material heat spreader with an insulating layer and a hydrophilic layer, which has high thermal conductivity and can also achieve the functions of efficient heating and buffering protection.

[0130] Example 2

[0131] The experimental steps for preparing the hydrophilic layer of the metal wire are based on the steps of Example 1, except that different weight ratios of insulating varnish and basic copper carbonate are used to prepare the hydrophilic layer.

[0132] The porosity of the porous hydrophilic structure was tested by volumetric method, and its porosity was determined based on the volume of the prepared structure. The volume of the prepared coating with porous structure was compared with that of the coating without porous structure.

[0133] ;in is the coating volume without preparing porous structure; is the volume after preparing the porous structure.

[0134] The performance of the metal wires with different porosities prepared by using different weight ratios of insulating varnish and basic copper carbonate and the heat spreaders prepared by using the metal wire wicks with different porosities are compared. The results are shown in Table 2.

[0135] Since the heat spreaders prepared based on Example 1 all have buffer protection functions, the heat dissipation performance and heating performance of different heat spreaders are compared, wherein the heat dissipation performance is compared by thermal conductivity, and the heating performance is compared by the time it takes to heat two battery cells from 0°C to 5°C at a power of 800 W.

[0136] Table 2 Comparison of the performance of vapor chambers with different porosity of the wick metal wire

[0137] Insulating varnish (wt%) Basic copper carbonate (wt%) Porosity(%) Thermal conductivity of vapor chamber (W / (m·K)) Heating time (s) 90 10 5 1730 170 80 20 10 1784 154 70 30 20 1800 150 60 40 30 1818 147 50 50 40 1837 142 40 60 50 1780 155

[0138] Comparative Example 6

[0139] During the preparation of the hydrophilic layer, the basic copper carbonate material was replaced with ammonium carbonate.

[0140] (1) Processing of insulation layer of metal wire

[0141] A fine manganese-copper alloy wire with a resistance value of 1.8 Ω / m and a wire diameter of 0.2 mm is used. A layer of insulating paint is sprayed on the surface of the wire. The insulating paint material is polyimide. The wire is baked and cured at a temperature of 200 °C for 30 min to obtain a wire with an insulating layer on the surface. The preparation process diagram is shown in the figure. Figure 1 As shown, 1 is a metal wire and 2 is an insulating layer.

[0142] (2) Hydrophilic layer processing of metal wire

[0143] Take the prepared metal wire with an insulating layer on the surface, use an insulating paint of the same material as the insulating layer, take 70 parts of insulating paint and 30 parts of ammonium carbonate powder by weight, fully mix and stir the insulating paint and ammonium carbonate particle powder to obtain a composite paint, spray it on the metal wire with an insulating layer on the surface, and bake and cure it after spraying. The baking temperature is 205 ° C and the baking time is 30 min to obtain a metal wire with an insulating layer and a hydrophilic layer. The porosity of the porous hydrophilic layer is 20%.

[0144] (3) Preparation of braided absorbent core

[0145] Take 8 prepared insulated metal wires and spirally weave them into a braided belt structure, such as Figure 2 As shown, 5 is an insulated metal wire and 6 is a metal braided belt absorbent core structure.

[0146] (4) Heat sink shell manufacturing

[0147] Take a braided absorbent core, and use a metal insert injection molding process to arrange the braided absorbent core in a serpentine shape in the mold, and inject the TPEE elastomer material to form a lower shell with an absorbent core and a support column. During the molding process of the lower shell, the support column and the shell are integrally formed, and the bent part of the absorbent core is completely embedded and fixed in the two frames. The two ends pass through and extend out of the frames, and the middle section is exposed on the inner surface of the shell and remains perpendicular to the two frames where the bent part of the absorbent core is embedded and fixed. The outer dimensions of the lower shell of the heat spreader are 600×400×3 mm. An upper shell with a size of 600×400×1 mm is also prepared by injection molding, and the material is the same as that of the lower shell. Figure 3 and Figure 4 As shown, 6 is a metal braided belt absorbent core structure, 7 is a support column, 8 is a lower shell, and 9 is an upper shell.

[0148] (5) Heat sink packaging

[0149] The prepared vapor chamber lower shell and upper shell are spliced ​​and sealed, and then a series of processes such as vacuuming, filling with liquid working medium and sealing are carried out. The liquid working medium filled is deionized water, and the vapor chamber is prepared. Figure 3 As shown, 6 is a metal braided belt absorbent core structure, 7 is a support column, 8 is a lower shell, and 9 is an upper shell.

[0150] (6) Application of heat spreader in battery thermal management and protection

[0151] The heat spreader is arranged between adjacent battery cells. The heat spreader contains liquid working fluid and a woven belt wick structure. The shell of the heat spreader is made of elastomeric material. The overall hardness of the heat spreader is less than the hardness of the battery cell. When the battery cell is collided, the heat spreader is deformed by the impact force of the battery cell, thereby playing a buffering role and protecting the battery.

[0152] Under high temperature conditions, the liquid working medium in the heat spreader changes into steam after being heated in a low vacuum environment. The steam quickly fills the inner cavity of the heat spreader. When the steam contacts the low temperature area of ​​the heat exchange device, it condenses into liquid working medium and releases heat. The condensed liquid working medium flows back to the heat source through the capillary pressure of the wick structure. By repeatedly exchanging heat in the cavity, the heat dissipation and heat equalization of the battery pack are achieved. The metal braided wick structure of the heat spreader is connected to an external power supply. Under low temperature conditions, the current generates heat through the metal wire with a certain resistance in the wick structure, causing the liquid working medium in the heat spreader to change into steam when heated in a low vacuum environment. The steam quickly fills the inside of the heat spreader, and the heat spreads over the entire heat spreader. The heat is quickly and evenly transferred to the battery cells through the heat spreader, thereby achieving heating of the battery at low temperatures. Figure 5 As shown, 10 is a battery unit, and 11 is a heat spreader with heating and buffering functions.

[0153] The heat spreader shell with heating and buffering functions prepared in Comparative Example 6 is made of an elastomeric material, and the heat spreader has a buffering and protective function. The thermal conductivity of the heat spreader is 1450 W / (m·K), and the time for heating two battery cells from 0°C to 5°C at 800W power is 200 s. The functions and various performances of the heat spreaders prepared in Example 1 and Comparative Example 6 are compared, and the results are shown in Table 3.

[0154] Table 3 Performance comparison results of the vapor chambers prepared in Example 1 and Comparative Example 6

[0155] name Characteristics of Vapor Chamber Thermal conductivity (W / (m·K)) Heating time (s) Buffer protection function Example 1 Basic copper carbonate 1800 150 have Comparative Example 6 Ammonium carbonate was used in the preparation of the hydrophilic layer. 1450 200 have

[0156] Considering that the thermal decomposition temperature of ammonium carbonate during the preparation of the hydrophilic layer is 58-60 ℃, and the initial curing temperature of the insulating paint is around 200 ℃, the insulating paint is not dried and solidified when the ammonium carbonate is thermally decomposed. After the ammonium carbonate is separated, the insulating paint is easy to flow and deform during curing, resulting in an unstable structure of the porous hydrophilic layer prepared in the end, which cannot provide good hydrophilicity. When used in the liquid wick in the heat spreader, it cannot provide sufficient capillary pressure, and the prepared heat spreader has poor performance.

[0157] Example 3

[0158] (1) Processing of insulation layer of metal wire

[0159] A fine manganese-copper alloy wire with a resistance value of 3.2 Ω / m and a wire diameter of 0.4 mm was used. A layer of insulating paint was sprayed on the surface of the wire. The insulating paint material was polyimide. The wire was baked and cured at a temperature of 220 °C for 20 min to obtain a wire with an insulating layer on the surface. The schematic diagram of the preparation process is shown in FIG. Figure 1 As shown, 1 is a metal wire and 2 is an insulating layer.

[0160] (2) Hydrophilic layer processing of metal wire

[0161] Take the prepared metal wire with an insulating layer on the surface, use an insulating paint of the same material as the insulating layer, take 50 parts of insulating paint and 50 parts of basic copper carbonate powder by weight, fully mix and stir the insulating paint and basic copper carbonate particle powder to obtain a composite paint, spray it on the metal wire with an insulating layer on the surface, bake and cure it after spraying, the baking temperature is 220 ° C, the baking time is 20 min, and after baking and curing, the residual copper oxide particles are removed by sulfuric acid solution to obtain a metal wire with an insulating layer and a hydrophilic layer, such as Figure 1 As shown, 3 is basic copper carbonate particles, 4 is a porous hydrophilic layer, and the porosity of the porous hydrophilic layer is 40%.

[0162] (3) Preparation of braided absorbent core

[0163] Take 5 prepared insulated metal wires and spirally weave them into a braided belt structure, such as Figure 2 As shown, 5 is an insulated metal wire and 6 is a metal braided belt absorbent core structure.

[0164] (4) Heat sink shell manufacturing

[0165] Take a braided absorbent core, and use a metal insert injection molding process to arrange the braided absorbent core in a serpentine shape in the mold, and inject the TPEE elastomer material to form a lower shell with an absorbent core and a support column. During the molding process of the lower shell, the support column and the shell are integrally formed, and the bent part of the absorbent core is completely embedded and fixed in the two frames. The two ends pass through and extend out of the frames, and the middle section is exposed on the inner surface of the shell and remains perpendicular to the two frames where the bent part of the absorbent core is embedded and fixed. The outer dimensions of the lower shell of the heat spreader are 600×400×3 mm. An upper shell with a size of 600×400×1 mm is also prepared by injection molding, and the material is the same as that of the lower shell. Figure 3 and Figure 4 As shown, 6 is a metal braided belt absorbent core structure, 7 is a support column, 8 is a lower shell, and 9 is an upper shell.

[0166] (5) Heat sink packaging

[0167] The prepared vapor chamber lower shell and upper shell are spliced ​​and sealed, and then a series of processes such as vacuuming, filling with liquid working medium and sealing are carried out. The liquid working medium filled is deionized water, and the vapor chamber is prepared. Figure 3 As shown, 6 is a metal braided belt absorbent core structure, 7 is a support column, 8 is a lower shell, and 9 is an upper shell.

[0168] (6) Application of heat spreader in battery thermal management and protection

[0169] The heat spreader is arranged between adjacent battery cells. The heat spreader contains liquid working fluid and a woven belt wick structure. The shell of the heat spreader is made of elastomeric material. The overall hardness of the heat spreader is less than the hardness of the battery cell. When the battery cell is collided, the heat spreader is deformed by the impact force of the battery cell, thereby playing a buffering role and protecting the battery.

[0170] Under high temperature conditions, the liquid working medium in the heat spreader changes into steam after being heated in a low vacuum environment. The steam quickly fills the inner cavity of the heat spreader. When the steam contacts the low temperature area of ​​the heat exchange device, it condenses into liquid working medium and releases heat. The condensed liquid working medium flows back to the heat source through the capillary pressure of the wick structure. By repeatedly exchanging heat in the cavity, the heat dissipation and heat equalization of the battery pack are achieved. The metal braided wick structure of the heat spreader is connected to an external power supply. Under low temperature conditions, the current generates heat through the metal wire with a certain resistance in the wick structure, causing the liquid working medium in the heat spreader to change into steam when heated in a low vacuum environment. The steam quickly fills the inside of the heat spreader, and the heat spreads over the entire heat spreader. The heat is quickly and evenly transferred to the battery cells through the heat spreader, thereby achieving heating of the battery at low temperatures. Figure 5 As shown, 10 is a battery unit, and 11 is a heat spreader with heating and buffering functions.

[0171] The heat spreader shell with heating and buffering functions prepared in Example 3 is made of elastomeric material. The heat spreader has the function of buffering and protection. The thermal conductivity of the heat spreader is 1830 W / (m·K). The time for heating two battery cells from 0°C to 5°C at a power of 800W is 143 s.

[0172] Example 4

[0173] (1) Processing of insulation layer of metal wire

[0174] A fine manganese-copper alloy wire with a resistance value of 1.5 Ω / m and a wire diameter of 0.2 mm is used. A layer of insulating paint is sprayed on the surface of the wire. The insulating paint material is polyamide-imide. The wire is baked and cured at a temperature of 200 °C for 40 min to obtain a wire with an insulating layer on the surface. The preparation process diagram is shown in FIG. Figure 1As shown, 1 is a metal wire and 2 is an insulating layer.

[0175] (2) Hydrophilic layer processing of metal wire

[0176] Take the prepared metal wire with an insulating layer on the surface, use an insulating paint of the same material as the insulating layer, take 80 parts of insulating paint and 20 parts of basic copper carbonate powder by weight, fully mix and stir the insulating paint and basic copper carbonate particle powder to obtain a composite paint, spray it on the metal wire with an insulating layer on the surface, bake and cure it after spraying, the baking temperature is 220 ° C, the baking time is 20 min, and after baking and curing, the residual copper oxide particles are removed by sulfuric acid solution to obtain a metal wire with an insulating layer and a hydrophilic layer, such as Figure 1 As shown, 3 is basic copper carbonate particles, 4 is a porous hydrophilic layer, and the porosity of the porous hydrophilic layer is 10%.

[0177] (3) Preparation of braided absorbent core

[0178] Take 15 prepared insulated metal wires and spirally weave them into a braided belt structure, such as Figure 2 As shown, 5 is an insulated metal wire and 6 is a metal braided belt absorbent core structure.

[0179] (4) Heat sink shell manufacturing

[0180] Take a braided absorbent core, and use a metal insert injection molding process to arrange the braided absorbent core in a serpentine shape in the mold, and inject the TPEE elastomer material to form a lower shell with an absorbent core and a support column. During the molding process of the lower shell, the support column and the shell are integrally formed, and the bent part of the absorbent core is completely embedded and fixed in the two frames. The two ends pass through and extend out of the frames, and the middle section is exposed on the inner surface of the shell and remains perpendicular to the two frames where the bent part of the absorbent core is embedded and fixed. The outer dimensions of the lower shell of the heat spreader are 600×400×3 mm. An upper shell with a size of 600×400×1 mm is also prepared by injection molding, and the material is the same as that of the lower shell. Figure 3 and Figure 4 As shown, 6 is a metal braided belt absorbent core structure, 7 is a support column, 8 is a lower shell, and 9 is an upper shell.

[0181] (5) Heat sink packaging

[0182] The prepared vapor chamber lower shell and upper shell are spliced ​​and sealed, and then a series of processes such as vacuuming, filling with liquid working medium and sealing are carried out. The liquid working medium filled is deionized water, and the vapor chamber is prepared. Figure 3 As shown, 6 is a metal braided belt absorbent core structure, 7 is a support column, 8 is a lower shell, and 9 is an upper shell.

[0183] (6) Application of heat spreader in battery thermal management and protection

[0184] The heat spreader is arranged between adjacent battery cells. The heat spreader contains liquid working fluid and a woven belt wick structure. The shell of the heat spreader is made of elastomeric material. The overall hardness of the heat spreader is less than the hardness of the battery cell. When the battery cell is collided, the heat spreader is deformed by the impact force of the battery cell, thereby playing a buffering role and protecting the battery.

[0185] Under high temperature conditions, the liquid working medium in the heat spreader changes into steam after being heated in a low vacuum environment. The steam quickly fills the inner cavity of the heat spreader. When the steam contacts the low temperature area of ​​the heat exchange device, it condenses into liquid working medium and releases heat. The condensed liquid working medium flows back to the heat source through the capillary pressure of the wick structure. By repeatedly exchanging heat in the cavity, the heat dissipation and heat equalization of the battery pack are achieved. The metal braided wick structure of the heat spreader is connected to an external power supply. Under low temperature conditions, the current generates heat through the metal wire with a certain resistance in the wick structure, causing the liquid working medium in the heat spreader to change into steam when heated in a low vacuum environment. The steam quickly fills the inside of the heat spreader, and the heat spreads over the entire heat spreader. The heat is quickly and evenly transferred to the battery cells through the heat spreader, thereby achieving heating of the battery at low temperatures. Figure 5 As shown, 10 is a battery unit, and 11 is a heat spreader with heating and buffering functions.

[0186] The heat spreader shell with heating and buffering functions prepared in Example 4 is made of elastomeric material. The heat spreader has the function of buffering and protection. The thermal conductivity of the heat spreader is 1786 W / (m·K). The time for heating two battery cells from 0°C to 5°C at a power of 800W is 153 s.

[0187] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A heat spreader with heating and buffering functions, characterized in that: From top to bottom, it includes an upper shell, a support unit, a liquid absorbent core unit and a lower shell. The upper shell, the support unit and the lower shell form a sealed cavity. The upper shell and the lower shell are connected through the support unit. The support unit includes a plurality of support columns. Liquid absorbent core units are arranged in a serpentine shape in the gaps between adjacent columns of the support columns. The bent part of the liquid absorbent core unit is embedded and fixed in the frame of the lower shell. Both ends of the liquid absorbent core unit pass through and extend out of the frame to be connected to a power source. The middle section of the liquid absorbent core unit is exposed on the inner surface of the shell. The liquid absorbent core unit is a woven belt made of multiple surface-insulated metal wires. The surface-insulated metal wires include metal wires and an insulating layer and a porous hydrophilic layer covering the surface of the metal wires from the inside to the outside. The materials of the upper shell and the lower shell are both elastomeric materials.

2. The heat spreader with heating and buffering functions according to claim 1, characterized in that: The porosity of the porous hydrophilic layer is 10%-40%.

3. The heat spreader with heating and buffering functions according to claim 1, characterized in that: The resistance of the metal wire is 1.5-3.2 Ω / m.

4. The heat spreader with heating and buffering functions according to claim 1, characterized in that: The method for preparing the insulated metal wire comprises: 1) Spray insulating paint on the surface of the metal wire and solidify it to obtain a metal wire with an insulating layer on the surface; 2) Spraying a composite paint on the metal wire with an insulating layer on the surface, performing secondary curing, and pickling to obtain an insulated metal wire with an insulating layer and a porous hydrophilic layer; the composite paint comprises 50-80 parts of insulating paint and 20-50 parts of basic copper carbonate powder.

5. The heat spreader with heating and buffering functions according to claim 4, characterized in that: The thickness of the insulating layer is 0.01-0.03 mm; the thickness of the porous hydrophilic layer is 0.01-0.03 mm.

6. The heat spreader with heating and buffering functions according to claim 4, characterized in that: The diameter of the metal wire is 0.2-0.4 mm; the curing temperature in step (1) is 200-220°C and the time is 20-40 min; the secondary curing temperature in step (2) is 200-220°C and the time is 20-40 min.

7. The vapor chamber with heating and buffering functions according to any one of claims 1 to 6, characterized in that: The liquid absorbent core unit is obtained by spirally weaving or arranging 5 to 15 insulating metal wires in parallel.

8. A method for preparing a vapor chamber with heating and buffering functions as claimed in any one of claims 1 to 7, characterized in that: include: S1, arranging the absorbent core unit in a serpentine shape in a mold, using a metal insert injection molding process, and injecting an elastomer material to form a lower shell with the absorbent core unit and the support unit; During the molding process of the lower shell, the support unit is integrally molded with the shell; S2. Splice the lower shell and the upper shell with the liquid wick unit and the support unit and seal them together, then evacuate, inject liquid working medium, and seal to obtain a heat spreader with heating and buffering functions.

9. The method according to claim 8, characterized in that The sealing connection is one of hot pressing welding, hot air welding, high frequency welding and adhesive bonding; the liquid working medium is one of deionized water, ethanol and acetone.

10. A power battery, characterized in that: The power battery comprises a vapor chamber with heating and buffering functions as described in any one of claims 1 to 7.

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