Heat absorption material and preparation method thereof, heat absorption piece, battery assembly and electric equipment
By preparing hydrogel heat-absorbing materials under an inert atmosphere and combining a three-dimensional network structure of polyacrylamide and sodium polyacrylate, the problems of insufficient compressive strength and heat absorption performance of heat-absorbing materials were solved, thereby improving the safety and performance of battery components.
Patent Information
- Application Number
- CN202410564252.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-04-30
- Publication Date
- 2025-10-31
AI Technical Summary
In existing technologies, heat-absorbing materials cannot simultaneously achieve both pressure resistance and heat absorption performance, and cannot effectively prevent heat transfer during battery thermal runaway, thus affecting the safety and performance of batteries and electrical equipment.
The hydrogel endothermic material prepared under an inert atmosphere forms a three-dimensional network structure with polyacrylamide and sodium polyacrylate. Combined with the phase change endothermic effect of water, it has excellent endothermic performance and compressive strength. The suitable weight loss rate is 70%-98%, and the integral area of the endothermic peak in the differential scanning calorimetry curve in the range of 40℃-200℃ is 1200J/g-2300J/g.
It effectively absorbs the heat generated by the battery module, prevents thermal runaway, improves the performance and lifespan of electrical equipment, has strong pressure resistance, is easy to encapsulate, and reduces the safety hazards of the battery module.
Smart Images
Figure CN120865480A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of battery technology, specifically to heat-absorbing materials and their preparation methods, heat-absorbing components, battery modules, and electrical devices. Background Technology
[0002] Batteries provide power for electrical devices, and temperature changes during battery use affect the performance and safety of both the battery and the device. Currently, low thermal conductivity insulation materials are used to reduce heat transfer between adjacent batteries, ensuring device operation. However, batteries can experience thermal runaway due to physical damage or other reasons. When a battery experiences thermal runaway, it generates a large amount of heat, which insulation materials often struggle to effectively prevent from being transferred to adjacent batteries. Some technologies incorporate heat-absorbing materials between batteries to absorb the heat generated during thermal runaway, but these materials often fail to balance pressure resistance and heat absorption performance. Summary of the Invention
[0003] In view of this, this application provides a heat-absorbing material and its preparation method, a heat-absorbing component, a battery assembly, and an electrical device. The heat-absorbing material has excellent heat absorption effect, can effectively prevent heat transfer, and has strong compressive strength, which is beneficial to the use of the heat-absorbing material.
[0004] In a first aspect, this application provides a heat-absorbing material in which, under an inert gas atmosphere, the weight loss rate of the heat-absorbing material is 70%-98% when heated from 25°C to 200°C; and in the differential scanning calorimetry curve of the heat-absorbing material, the integral area of the heat-absorbing peak in the range of 40°C-200°C is 1200J / g-2300J / g.
[0005] Optionally, in a thermogravimetric analysis test conducted under an inert gas atmosphere, with the temperature increasing from 25°C to 200°C, the weight loss rate of the heat-absorbing material is 80%-95%.
[0006] Optionally, in the differential scanning calorimetry curve of the heat-absorbing material, the integral area of the heat-absorbing peak in the range of 40℃-200℃ is 1650J / g-2000J / g.
[0007] Optionally, in the differential scanning calorimetry curve of the heat-absorbing material, the integral area of the heat-absorbing peak in the range of 40℃-80℃ is 72J / g-150J / g.
[0008] Optionally, in the differential scanning calorimetry curve of the heat-absorbing material, the integral area of the heat-absorbing peak in the range of 80℃-140℃ is 1100J / g-2070J / g.
[0009] Optionally, in the differential scanning calorimetry curve of the heat-absorbing material, the integral area of the heat-absorbing peak in the range of 140℃-200℃ is 100J / g-300J / g.
[0010] Optionally, the heat-absorbing material is a hydrogel.
[0011] Optionally, in the infrared spectrum of the heat-absorbing material, at 1640 cm⁻¹... -1 -1700cm -1 It has a first infrared absorption peak at 1040 cm⁻¹ -1 -1100cm -1 It has a second infrared absorption peak at 720 cm⁻¹ -1 -930cm -1 It has a third infrared absorption peak at 3352 cm⁻¹ -1 -3382cm -1 It has a fourth infrared absorption peak at 2920 cm⁻¹ -1 -2955cm -1 It has a fifth infrared absorption peak at 1445 cm⁻¹ -1 -1465cm -1 It has a sixth infrared absorption peak.
[0012] Optionally, the heat-absorbing material comprises 1 wt%-10 wt% polyacrylamide, 1 wt%-10 wt% sodium polyacrylate, and water.
[0013] Optionally, the heat-absorbing material may further include at least one of polyacrylic acid, ethylene glycol, and glycerin.
[0014] Optionally, the content of polyacrylic acid in the heat-absorbing material is less than or equal to 10 wt%.
[0015] Optionally, the content of ethylene glycol in the heat-absorbing material is less than or equal to 10 wt%.
[0016] Optionally, the content of glycerol in the heat-absorbing material is less than or equal to 20 wt%.
[0017] Optionally, the inert gas atmosphere includes at least one of argon, helium, and nitrogen.
[0018] Secondly, this application provides a method for preparing a heat-absorbing material, comprising mixing acrylamide, sodium polyacrylate, water, a crosslinking agent and an initiator, and reacting to obtain the heat-absorbing material described in the first aspect.
[0019] Optionally, the reaction temperature is 50℃-60℃, and the reaction time is 2h-5h.
[0020] Thirdly, this application provides a heat-absorbing element, including the heat-absorbing material described in the first aspect or the heat-absorbing material prepared by the preparation method described in the second aspect.
[0021] Optionally, the heat-absorbing element further includes an encapsulation structure, the encapsulation structure having an internal accommodating space, and the heat-absorbing material disposed in the accommodating space.
[0022] Fourthly, this application provides a battery assembly, which includes a battery and the heat-absorbing element described in the third aspect.
[0023] Fifthly, this application provides an electrical device including the battery assembly described in the fourth aspect.
[0024] The heat-absorbing material provided in this application has a high weight loss rate and a large latent heat of phase change. At the same time, the heat-absorbing material has a suitable integral area of the heat-absorbing peak in the differential scanning calorimetry curve, indicating good heat absorption performance and excellent compressive strength, which is beneficial to the use of the heat-absorbing material. The heat-absorbing component with this heat-absorbing material has excellent heat absorption and compressive strength, and can effectively absorb the heat generated during the use of the battery assembly, which helps to improve the performance and service life of the electrical equipment. Attached Figure Description
[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. The specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.
[0026] Figure 1 This is a cross-sectional schematic diagram of a heat-absorbing element provided in one embodiment of this application.
[0027] Figure 2 This is a cross-sectional schematic diagram of a battery assembly provided in one embodiment of this application.
[0028] Figure 3 A cross-sectional schematic diagram of a battery assembly provided for another embodiment of this application.
[0029] Figure 4 The infrared spectrum of the hydrogel heat-absorbing material in Example 2 is shown.
[0030] Figure 5 The DSC curve of the hydrogel heat-absorbing material in Example 8 is shown. Detailed Implementation
[0031] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.
[0032] This application provides a heat-absorbing material. In a thermogravimetric analysis test conducted under an inert gas atmosphere, the weight loss rate of the heat-absorbing material is 70%-98% when the temperature rises from 25°C to 200°C. In the differential scanning calorimetry curve of the heat-absorbing material, the integral area of the heat-absorbing peak in the range of 40°C-200°C is 1200J / g-2300J / g. Thermogravimetric analysis (TG) is a thermal analysis technique that measures the relationship between the mass and temperature of a substance under programmed temperature control, yielding a TG curve. In this application, TG testing was conducted under an inert gas atmosphere. The weight of the heat-absorbing material at 25°C was m0, and when the temperature was increased to 200°C at a rate of 10°C / min, the weight decreased to m1. The weight loss rate of the heat-absorbing material during the TG test from 25°C to 200°C was (m0-m1) / m0. Taking a hydrogel heat-absorbing material as an example, during the temperature increase from 25°C to 200°C, the water in the hydrogel heat-absorbing material changes from a liquid to a gaseous state, resulting in a weight loss. The gas-phase change process is an endothermic process, ensuring the heat absorption effect of the hydrogel heat-absorbing material. In the thermogravimetric analysis test from 25℃ to 200℃, when the weight loss rate of the hydrogel heat-absorbing material is less than 70%, the water content in the hydrogel heat-absorbing material is too low, the latent heat of phase change is low, and the heat absorption capacity is low, which cannot meet the heat absorption requirements. When the weight loss rate of the hydrogel heat-absorbing material is greater than 98%, the hydrogel heat-absorbing material is almost entirely water, with high fluidity, weak compressive strength, and difficulty in encapsulation, which is not conducive to the use of the hydrogel heat-absorbing material. Therefore, when the weight loss rate of the hydrogel heat-absorbing material is 70%-98%, the weight loss rate of the hydrogel heat-absorbing material is suitable, and more water undergoes liquid-gas phase change, producing a significant heat absorption effect and effectively absorbing external heat. Differential scanning calorimetry (DSC) is a thermal analysis method that measures the difference in heat flux between a substance and a reference material as a function of temperature under programmed temperature control. The DSC integral area, measured by integrating the endothermic and exothermic peaks, is expressed in J / g and characterizes the heat absorbed / released per unit weight of sample during a physical / chemical process. In this application, DSC analysis was performed under an inert gas atmosphere. The temperature was increased from 25°C to 200°C at a rate of 10°C / min, resulting in a differential scanning calorimetry curve (DSC curve). The integral area of the endothermic peaks within the 40°C-200°C range refers to the total integral area of the endothermic peaks within this range, representing the change in enthalpy per unit weight of endothermic material from 40°C to 200°C. J / g is the unit of enthalpy for a unit weight of endothermic material.Taking hydrogel heat-absorbing materials as an example, in the DSC curve of hydrogel heat-absorbing materials, when the integral area of the endothermic peak in the 40℃-200℃ range is less than 1200 J / g, the water content of the hydrogel heat-absorbing material is too low, resulting in weak heat absorption capacity. When the integral area of the endothermic peak in the 40℃-200℃ range is greater than 2300 J / g, the water content of the hydrogel heat-absorbing material is too high, making the hydrogel heat-absorbing material too soft, with weak compressive strength and difficult to encapsulate, which is not conducive to the use of hydrogel heat-absorbing materials. Therefore, when the integral area of the endothermic peak in the 40℃-200℃ range is 1200 J / g-2300 J / g, the hydrogel heat-absorbing material has excellent heat absorption capacity and strong compressive strength. As can be seen, the heat-absorbing material provided in this application has excellent heat absorption performance. When used in battery modules, it can effectively reduce the heat generated by the battery. It can replace the existing hydrogel for heat insulation, solve the problem of battery module heating from the root, and prevent battery overheating runaway. In addition, the hydrogel heat-absorbing material also has excellent compressive strength, is easy to encapsulate, and has a low probability of being damaged when the battery expands or is subjected to external force, thus ensuring the service life of the hydrogel heat-absorbing material and helping to ensure the normal use of electrical equipment.
[0033] In thermogravimetric analysis (TGA) tests conducted under an inert gas atmosphere, with temperatures increasing from 25°C to 200°C, the weight loss rate of the heat-absorbing material ranged from 70% to 98%. This heat-absorbing material exhibits excellent heat absorption properties and compressive strength, which is beneficial for its encapsulation and use. In this application, the TGA analysis was performed under an inert gas atmosphere, with a heating rate of 10°C / min. Specifically, in a thermogravimetric analysis test conducted under an inert gas atmosphere, from 25°C to 200°C, the weight loss rate of the endothermic material can be, but is not limited to, 70%, 71%, 72%, 73%, 73.5%, 74%, 75%, 76%, 77%, 78%, 78.2%, 79%, 80%, 81%, 82%, 82.8%, 83%, 84%, 85%, 85.5%, 86%, 87%, 88%, 89%, 90%, 91%, 91.6%, 92%, 93%, 94%, 95%, 95.5%, 96%, 97%, or 98%, etc.; the inert gas atmosphere can be, but is not limited to, at least one of argon, helium, and nitrogen. In one embodiment of this application, under an inert gas atmosphere, in a thermogravimetric analysis test from 25°C to 200°C, the weight loss rate of the heat-absorbing material is 80%-95%, further improving the heat absorption capacity and compressive strength of the heat-absorbing material, which is beneficial for its encapsulation and use. In another embodiment of this application, under an inert gas atmosphere, in a thermogravimetric analysis test from 25°C to 200°C, the weight loss rate of the heat-absorbing material can be 80%-85%. In another embodiment of this application, under an inert gas atmosphere, in a thermogravimetric analysis test from 25°C to 200°C, the weight loss rate of the heat-absorbing material can be 85%-90%. In yet another embodiment of this application, under an inert gas atmosphere, in a thermogravimetric analysis test from 25°C to 200°C, the weight loss rate of the heat-absorbing material can be 90%-95%.
[0034] In the differential scanning calorimetry (DSC) curve of the heat-absorbing material, the integral area of the endothermic peak in the 40℃-200℃ range is 1200 J / g-2300 J / g. This heat-absorbing material exhibits excellent heat absorption performance and compressive strength, which is beneficial for its encapsulation and use. Specifically, the integral area of the endothermic peak in the 40℃-200℃ range of the differential scanning calorimetry curve of the heat-absorbing material can be, but is not limited to, 1200 J / g, 1250 J / g, 1300 J / g, 1320 J / g, 1350 J / g, 1400 J / g, 1450 J / g, 1470 J / g, 1500 J / g, 1550 J / g, 1600 J / g, 1630 J / g, 1... The heat absorption capacity is 650 J / g, 1700 J / g, 1750 J / g, 1770 J / g, 1800 J / g, 1850 J / g, 1900 J / g, 1950 J / g, 1980 J / g, 2000 J / g, 2050 J / g, 2100 J / g, 2150 J / g, 2200 J / g, 2230 J / g, 2250 J / g, 2290 J / g, or 2300 J / g, etc. In one embodiment of this application, the differential scanning calorimetry curve of the heat-absorbing material shows that the integral area of the heat absorption peak in the range of 40℃-200℃ is 1650 J / g-2000 J / g, which further improves the heat absorption capacity and compressive strength of the heat-absorbing material, and is beneficial to the packaging and use of the heat-absorbing material. In one embodiment of this application, the differential scanning calorimetry (DSC) curve of the endothermic material shows an endothermic peak integral area of 1650 J / g-1850 J / g in the 40℃-200℃ range. In another embodiment, the DSC curve of the endothermic material shows an endothermic peak integral area of 1700 J / g-1900 J / g in the 40℃-200℃ range. In yet another embodiment, the DSC curve of the endothermic material shows an endothermic peak integral area of 1800 J / g-2000 J / g in the 40℃-200℃ range.
[0035] In one embodiment of this application, the integral area of the endothermic peak in the differential scanning calorimetry (DSC) curve of the endothermic material within the 40℃-80℃ range is 72 J / g-150 J / g. Specifically, the integral area of the endothermic peak in the 40℃-80℃ range of the DSC curve of the endothermic material can be, but is not limited to, 72 J / g, 75 J / g, 80 J / g, 85 J / g, 90 J / g, 95 J / g, 100 J / g, 105 J / g, 110 J / g, 115 J / g, 120 J / g, 125 J / g, 130 J / g, 135 J / g, 140 J / g, 145 J / g, or 150 J / g, etc. In one embodiment of this application, the integral area of the endothermic peak in the 40℃-80℃ range of the DSC curve of the endothermic material is 75 J / g-100 J / g. In another embodiment of this application, the differential scanning calorimetry (DSC) curve of the endothermic material shows that the integral area of the endothermic peak in the range of 40℃-80℃ is 80J / g-120J / g. In yet another embodiment of this application, the DSC curve of the endothermic material shows that the integral area of the endothermic peak in the range of 40℃-80℃ is 120J / g-150J / g.
[0036] In one embodiment of this application, the integral area of the endothermic peak in the differential scanning calorimetry (DSC) curve of the endothermic material in the range of 80℃-140℃ is 1100J / g-2070J / g. Specifically, the integral area of the endothermic peak in the DSC curve of the endothermic material in the range of 80℃-140℃ can be, but is not limited to, 1100J / g, 1150J / g, 1200J / g, 1250J / g, 1300J / g, 1350J / g, 1400J / g, 1450J / g, 1500J / g, 1550J / g, 1600J / g, 1650J / g, 1700J / g, 1750J / g, 1800J / g, 1850J / g, 1900J / g, 1950J / g, 2000J / g, or 2050J / g, etc. In one embodiment of this application, the differential scanning calorimetry (DSC) curve of the endothermic material shows an endothermic peak integral area of 1100 J / g-1450 J / g in the 80℃-140℃ range. In another embodiment, the DSC curve of the endothermic material shows an endothermic peak integral area of 1300 J / g-1700 J / g in the 80℃-140℃ range. In yet another embodiment, the DSC curve of the endothermic material shows an endothermic peak integral area of 1700 J / g-2000 J / g in the 80℃-140℃ range.
[0037] In one embodiment of this application, the integral area of the endothermic peak in the differential scanning calorimetry (DSC) curve of the endothermic material in the range of 140℃-200℃ is 100J / g-300J / g. Specifically, the integral area of the endothermic peak in the DSC curve of the endothermic material in the range of 140℃-200℃ can be, but is not limited to, 100J / g, 110J / g, 120J / g, 130J / g, 140J / g, 150J / g, 160J / g, 170J / g, 180J / g, 190J / g, 200J / g, 210J / g, 220J / g, 230J / g, 240J / g, 255J / g, 260J / g, 270J / g, 280J / g, 290J / g, or 300J / g, etc. In one embodiment of this application, the differential scanning calorimetry (DSC) curve of the endothermic material shows an endothermic peak integral area of 100 J / g-170 J / g in the 140℃-200℃ range. In another embodiment, the DSC curve of the endothermic material shows an endothermic peak integral area of 170 J / g-230 J / g in the 140℃-200℃ range. In yet another embodiment, the DSC curve of the endothermic material shows an endothermic peak integral area of 230 J / g-300 J / g in the 140℃-200℃ range.
[0038] In one embodiment of this application, the differential scanning calorimetry (DSC) curve of the heat-absorbing material shows that the integral area of the endothermic peak in the 40℃-80℃ range is 72 J / g-150 J / g, the integral area in the 80℃-140℃ range is 1100 J / g-2070 J / g, and the integral area in the 140℃-200℃ range is 100 J / g-300 J / g. The large integral area of the endothermic peak in the 80℃-140℃ range indicates that the heat-absorbing material has a significant heat absorption effect in this range, resulting in higher heat absorption efficiency and effectively preventing the battery temperature from rising.
[0039] In one embodiment of this application, the heat-absorbing material is a hydrogel. Hydrogel heat-absorbing materials are mostly water, and water has a large latent heat of vaporization, which can absorb a large amount of heat, ensuring the heat-absorbing performance of the material.
[0040] In one embodiment of this application, the infrared spectrum of the heat-absorbing material shows a value at 1640 cm⁻¹. -1 -1700cm -1 It has a first infrared absorption peak at 1040 cm⁻¹ -1 -1100cm -1 It has a second infrared absorption peak at 720 cm⁻¹ -1 -930cm -1 It exhibits a third infrared absorption peak at 1640 cm⁻¹. -1 -1700cm -1The presence of the first infrared absorption peak indicates the presence of amide bonds (-CO-NH-) in the endothermic material, at 1040 cm⁻¹. -1 -1100cm -1 The presence of a second infrared absorption peak indicates the presence of carbon-carbon single bonds in the endothermic material, at 720 cm⁻¹. -1 -930cm -1 The presence of a third infrared absorption peak indicates the presence of amine (-NH2) and / or methylene groups in the heat-absorbing material. In one embodiment of this application, the infrared spectrum of the heat-absorbing material shows a peak at 3352 cm⁻¹. -1 -3382cm -1 The presence of a fourth infrared absorption peak indicates the presence of amine groups and / or water in the heat-absorbing material. In one embodiment of this application, the infrared spectrum of the heat-absorbing material shows a peak at 2920 cm⁻¹. -1 -2955cm -1 The presence of a fifth infrared absorption peak indicates the presence of methylene (-CH2) groups in the heat-absorbing material. In one embodiment of this application, the infrared spectrum of the heat-absorbing material shows a peak at 1445 cm⁻¹. -1 -1465cm -1 The presence of a sixth infrared absorption peak indicates the presence of methylene groups in the heat-absorbing material.
[0041] In one embodiment of this application, the heat-absorbing material includes polyacrylamide, sodium polyacrylate, and water. The polyacrylamide and sodium polyacrylate in the heat-absorbing material form a three-dimensional network structure, with water dispersed and loaded within this network. The phase change of water enables the heat-absorbing material to have a heat-absorbing effect. Specifically, when the battery temperature rises, the water in the heat-absorbing material changes from a liquid to a gaseous state upon heating. During this process, it absorbs heat, carrying away the heat generated by the battery and lowering the battery temperature. Simultaneously, the gaseous water vapor diffuses to the cooler end and condenses back into a liquid state, thus continuing the above cycle and achieving effective heat absorption and cooling. In one embodiment of this application, the polyacrylamide and sodium polyacrylate in the heat-absorbing material form an interpenetrating network structure, further improving the water absorption performance and flexibility of the heat-absorbing material.
[0042] In one embodiment of this application, according to the ASTM D695 test standard, a pressure of 0.5 MPa is applied to the heat-absorbing material along its thickness direction, resulting in a thickness deformation of 55%-85%. The thickness deformation is defined as the ratio of the change in thickness before and after pressure application to the original thickness of the heat-absorbing material before pressure application. The heat-absorbing material provided in this application exhibits excellent deformation after pressure application, indicating strong compressive strength and the ability to maintain structural integrity under certain pressure, which is beneficial for its use. Specifically, according to the ASTM D695 test standard, when a pressure of 0.5 MPa is applied to the heat-absorbing material along its thickness direction, the thickness deformation can be, but is not limited to, 55%-60%, 60%-65%, 65%-70%, 70%-75%, 75%-80%, or 80%-85%.
[0043] In one embodiment of this application, the heat-absorbing material comprises 1 wt%-10 wt% polyacrylamide, 1 wt%-10 wt% sodium polyacrylate, and water. Taking hydrogel heat-absorbing material as an example, the hydrogel heat-absorbing material is mostly water. Water has a large latent heat of vaporization and can absorb a large amount of heat. It plays a role in heat absorption through the phase change of water. At the same time, the appropriate amount of polyacrylamide and sodium polyacrylate ensures the flexibility of the heat-absorbing material, thereby giving the heat-absorbing material a certain compressive strength. It also increases the water content in the heat-absorbing material, thereby improving the heat absorption effect of the heat-absorbing material. Specifically, the content of polyacrylamide in the heat-absorbing material may be, but is not limited to, 1 wt%, 1.5 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 5.5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, or 10 wt%, etc.; the content of sodium polyacrylate in the heat-absorbing material may be, but is not limited to, 1 wt%, 1.5 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 5.5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, or 10 wt%, etc.
[0044] In one embodiment of this application, the heat-absorbing material further includes at least one of polyacrylic acid, ethylene glycol (C2H6O2), and glycerol (C3H8O3). Adding polyacrylic acid can further improve the flexibility and compressive strength of the heat-absorbing material and is beneficial for increasing its water content; adding ethylene glycol can improve the antifreeze effect of the heat-absorbing material; adding glycerol can further increase the water content of the heat-absorbing material. In one embodiment of this application, the content of polyacrylic acid in the heat-absorbing material is less than or equal to 10 wt%, further improving the overall performance of the heat-absorbing material. Specifically, the content of polyacrylic acid in the heat-absorbing material can be, but is not limited to, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, or 10 wt%. In one embodiment of this application, the content of ethylene glycol in the heat-absorbing material is less than or equal to 10 wt%, further improving the overall performance of the heat-absorbing material. Specifically, the content of ethylene glycol in the heat-absorbing material can be, but is not limited to, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, or 10 wt%. In one embodiment of this application, the content of glycerol in the heat-absorbing material is less than or equal to 20 wt%, further improving the overall performance of the heat-absorbing material. Specifically, the content of glycerol in the heat-absorbing material can be, but is not limited to, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, 11 wt%, 12 wt%, 13 wt%, 14 wt%, 15 wt%, 16 wt%, 17 wt%, 18 wt%, 19 wt%, or 20 wt%. In one embodiment, the heat-absorbing material comprises at least one of less than 10 wt% polyacrylic acid, less than 10 wt% ethylene glycol, and less than 20 wt% glycerol, and 1 wt%-10 wt% polyacrylamide, 1 wt%-10 wt% sodium polyacrylate, and the balance being water. Exemplarily, the heat-absorbing material comprises 1 wt%-10 wt% polyacrylamide, 1 wt%-10 wt% sodium polyacrylate, less than 10 wt% polyacrylic acid, less than 10 wt% ethylene glycol, less than 20 wt% glycerol, and 70 wt%-95 wt% water. This heat-absorbing material exhibits excellent heat absorption and compressive strength, which is beneficial for its use.
[0045] This application also provides a method for preparing a heat-absorbing material, comprising mixing acrylamide (C3H5NO), sodium polyacrylate, water, a crosslinking agent, and an initiator, and reacting to obtain the heat-absorbing material in any of the above embodiments. This preparation method is simple, convenient to operate, uses widely available and low-cost raw materials, and can produce heat-absorbing materials with excellent heat absorption performance, good compressive strength, and easy packaging. It also features low preparation cost, high preparation efficiency, and high yield, which is beneficial for the use of heat-absorbing materials.
[0046] In this application, during the reaction process, acrylamide and sodium polyacrylate undergo cross-linking polymerization under the action of a cross-linking agent and an initiator to form a three-dimensional network structure of the polymer, ensuring the water load and the compressive strength of the heat-absorbing material. Specifically, the cross-linking agent may be, but is not limited to, N,N-methylenebisacrylamide, and the initiator may be, but is not limited to, at least one of nitrogen diisobutylammonium hydrochloride and ammonium persulfate. In one embodiment of this application, the reaction temperature is 50℃-60℃, and the reaction time is 2h-5h, further ensuring the full progress of the cross-linking polymerization. Specifically, the reaction temperature may be, but is not limited to, 50℃, 52℃, 53℃, 55℃, 57℃, 58℃, or 60℃, and the reaction time may be, but is not limited to, 2h, 2.5h, 3h, 3.5h, 4h, 4.5h, or 5h.
[0047] In one embodiment of this application, the method for preparing the heat-absorbing material further includes mixing acrylamide, acrylic acid (C3H4O2), sodium polyacrylate, water, a crosslinking agent, and an initiator to react and obtain the heat-absorbing material. In another embodiment of this application, the method for preparing the heat-absorbing material further includes mixing acrylamide, sodium polyacrylate, water, ethylene glycol, a crosslinking agent, and an initiator to react and obtain the heat-absorbing material. In yet another embodiment of this application, the method for preparing the heat-absorbing material further includes mixing acrylamide, sodium polyacrylate, water, glycerol, a crosslinking agent, and an initiator to react and obtain the heat-absorbing material. Exemplarily, the method for preparing the heat-absorbing material includes mixing acrylamide, acrylic acid, and sodium polyacrylate evenly, adding them to a mixed solvent of water, ethylene glycol, and glycerol, heating, and then adding the crosslinking agent and initiator to react and obtain the heat-absorbing material. Specifically, the mixing temperature of acrylamide, acrylic acid, and sodium polyacrylate can be 10℃-35℃ to facilitate thorough and uniform mixing of the acrylamide, acrylic acid, and sodium polyacrylate; the heating temperature can be 50℃-60℃ to facilitate the dispersion and dissolution of the added substances. In one embodiment, acrylamide, acrylic acid, sodium polyacrylate, water, ethylene glycol, and glycerol form a mixed solution, and the amount of crosslinking agent added accounts for 0.015%-0.2% of the mass of the mixed solution. Specifically, the amount of crosslinking agent added accounts for 0.015%, 0.03%, 0.05%, 0.06%, 0.08%, 0.09%, 0.1%, 0.12%, 0.13%, 0.15%, 0.17%, 0.18%, or 0.2% of the mass of the mixed solution.
[0048] This application also provides a heat-absorbing element, comprising the heat-absorbing material in any of the above embodiments. The heat-absorbing material provided by this application improves the manufacturing yield of the heat-absorbing element, and at the same time, the heat-absorbing material has excellent heat absorption performance, thereby improving the heat absorption performance of the heat-absorbing element and facilitating its use.
[0049] In one embodiment of this application, the heat-absorbing component further includes an encapsulation structure, the interior of which has an accommodating space, and the heat-absorbing material is disposed within the accommodating space. Please refer to... Figure 1 This is a cross-sectional schematic diagram of a heat-absorbing component provided in one embodiment of this application. The heat-absorbing component 100 includes an encapsulation structure 20 and a heat-absorbing material 10. The encapsulation structure 20 has an internal accommodating space, and the heat-absorbing material 10 is disposed in the accommodating space. The encapsulation structure in the heat-absorbing component serves to seal and accommodate the heat-absorbing material. The heat-absorbing material provided in this application is easy to encapsulate, which is beneficial to the use of the heat-absorbing component. In this application, the encapsulation structure is used to encapsulate the heat-absorbing material and has excellent water vapor barrier effect. In one embodiment of this application, the material of the encapsulation structure includes aluminum, which ensures the sealing effect of the encapsulation structure and improves the service life of the heat-absorbing component. In one embodiment of this application, acrylamide, sodium polyacrylate, water, crosslinking agent and initiator can be mixed and placed inside the encapsulation structure, and the heat-absorbing component can be directly obtained after reaction.
[0050] This application also provides a battery assembly, including a battery and a heat-absorbing element as described in any of the above embodiments. In related technologies, heat-insulating materials are placed on the surface of the battery to block the transfer of heat after the battery generates heat. However, the heat of the battery is not reduced, and safety issues still exist, while also affecting the use of the battery assembly. This application solves the problem of battery overheating at its source by setting a heat-absorbing element to absorb the heat generated by the battery, eliminating the safety hazards that exist during the use of the battery assembly, and facilitating the use of the battery assembly. At the same time, the heat-absorbing element has strong compressive strength and will not rupture when the battery expands or is subjected to external forces, ensuring the reliability of the battery assembly.
[0051] Please see Figure 2 This is a cross-sectional schematic diagram of a battery assembly provided in one embodiment of this application. The battery assembly 300 includes a single battery 200 and a heat-absorbing element 100, the heat-absorbing element 100 being disposed on the surface of the battery 200. Please refer to... Figure 3 This is a cross-sectional schematic diagram of a battery assembly according to another embodiment of this application. The battery assembly 300 includes a plurality of batteries 200 and a heat absorber 100. A heat absorber 100 is disposed between at least two batteries 200, thereby further reducing the heat generated during the operation of the battery assembly and improving the operational safety of the battery assembly. In this application, the battery assembly may include a single battery and a heat absorber, or it may include multiple batteries and a heat absorber. When the battery assembly includes multiple batteries and a heat absorber, the battery assembly may be a battery module or a battery pack. The battery pack includes a housing and multiple batteries, which are housed in the housing. The multiple batteries may be housed in the housing in the form of a battery module or in a module-less manner.
[0052] This application provides an electrical device including the battery module described in any of the above embodiments. The electrical device provided by this application boasts excellent performance and lifespan, making it highly competitive. Specifically, the electrical device can refer to vehicles, electronic devices, energy storage systems, etc.
[0053] The effects of the technical solution in this application will be further illustrated below with specific examples.
[0054] Example 1
[0055] Mix 1 part by weight of acrylamide, 1 part by weight of sodium polyacrylate, 2 parts by weight of acrylic acid, 3 parts by weight of ethylene glycol, 3 parts by weight of glycerol, and 90 parts by weight of water until homogeneous. Add 0.1 parts by weight of crosslinking agent (N,N-methylenebisacrylamide) to the above solution while stirring continuously. Heat the mixture to 55°C and add 0.007 parts by weight of initiator (azobisisobutyramidine hydrochloride). Quickly transfer the resulting mixture to a horizontally placed elongated mold to allow it to self-level. Wait 3 hours for it to crosslink and solidify to obtain a hydrogel heat-absorbing material.
[0056] Examples 2-9
[0057] It is largely the same as Example 1, except that the weight proportions of the raw materials and the reaction conditions are different.
[0058] Comparative Examples 1-2
[0059] It is largely the same as Example 1, except that the weight proportions of the raw materials are different.
[0060] The weight parts of the raw materials and reaction conditions in the above embodiments and comparative examples are shown in Tables 1 and 2, where each raw material in Table 1 is a weight part value.
[0061] Table 1. Weight parts of raw materials
[0062]
[0063]
[0064] Table 2 Reaction conditions
[0065] Temperature / °C Time / h Example 1 55 3 Example 2 55 3 Example 3 55 3 Example 4 55 3 Example 5 55 3 Example 6 55 3 Example 7 50 5 Example 8 60 3 Example 9 55 4 Comparative Example 1 55 4 Comparative Example 2 55 4
[0066] Performance testing
[0067] Infrared spectroscopy was used to analyze the hydrogel heat-absorbing materials prepared in the examples and comparative examples according to GB / T6040-2002 after drying and sample preparation. Figure 4 The infrared spectrum of the hydrogel heat-absorbing material prepared in Example 2 is shown at 3359 cm⁻¹. -1 The peak is for -NH2 or H2O, at 2922 cm⁻¹. -1 The peak for -CH2 is eluted at 1662 cm⁻¹. -1 The peak is -CO-NH-, 1457 cm⁻¹ -1 The peak is for -CH2, at 1099 cm⁻¹. -1The peak is C3, at 723 cm⁻¹. -1 The peaks are for -NH2 or -CH2.
[0068] The hydrogel heat-absorbing materials prepared in the above examples and comparative examples were analyzed using a TG-DSC thermal analyzer. The analysis was conducted under an inert gas atmosphere (N2, flow rate 50 ml / min), with a test range of 25℃-200℃ and a heating rate of 10℃ / min. TG and DSC curves were obtained, and the weight loss rate of the hydrogel heat-absorbing material in the TG curve from 25℃ to 200℃ at a heating rate of 10℃ / min was calculated, as well as the integral area S of the endothermic peak in the 40℃-200℃ range. The results are shown in Table 3. The integral areas S1, S2, and S3 of the endothermic peaks in the 40℃-80℃ range, 80℃-140℃ range, and 140℃-200℃ range of the hydrogel heat-absorbing materials prepared in Examples 1 and 3 were calculated, and the results are shown in Table 4. Figure 5 The figure shows the DSC curve for Example 8, with the horizontal axis representing temperature (°C). The mass of the hydrogel heat-absorbing material provided in Example 8 is 4.4 mg, and the integral area of its endothermic peak in the range of 40°C-140°C is 1680 J / g.
[0069] The hydrogel heat-absorbing materials prepared in the examples and comparative examples were encapsulated with a polyethylene film with a thickness of 1 mm. The samples (5 mm in length and width, and 1 mm in thickness) conforming to the requirements of ASTM D695 standard were made. The electronic universal testing machine was configured to compression test mode, and a pressure of 0.5 MPa was applied to the sample along the test thickness direction. The thickness deformation was measured. The thickness deformation is the ratio of the change in thickness of the sample before and after applying pressure to the thickness of the sample before applying pressure.
[0070] Table 3 Performance test results
[0071]
[0072]
[0073] Table 4. Integral area of the endothermic peak in different temperature ranges
[0074] <![CDATA[S1 / J·g -1 ]]> <![CDATA[S2 / J·g -1 ]]> <![CDATA[S3 / J·g -1 ]]> Example 1 117 1601 128 Example 3 83 1299 217
[0075] As shown in Tables 1, 3, and 2, the higher the water content of the hydrogel heat-absorbing material, the larger the integral area of the endothermic peak and the greater the thickness deformation. The hydrogel heat-absorbing material prepared in Comparative Example 1 has a low water content and the smallest thickness deformation, but its weight loss rate and endothermic peak integral area are low, indicating that this hydrogel heat-absorbing material has good compressive strength but poor heat absorption performance. The hydrogel heat-absorbing material prepared in Comparative Example 2 has a high weight loss rate and endothermic peak integral area, indicating good heat absorption performance. However, due to its excessive water content, its compressive strength is weak. During the pressure application process, both the polyethylene film and the hydrogel heat-absorbing material rupture, rendering it unusable. Therefore, the hydrogel heat-absorbing material prepared in Comparative Example 2 has weak compressive strength, which is detrimental to its use. The hydrogel heat-absorbing materials prepared in Examples 1-9 exhibited a weight loss rate of 70%-97% in thermogravimetric analysis tests conducted from 25°C to 200°C, and an endothermic peak integral area of 1200 J / g-2300 J / g within the 40°C-200°C range. These weight loss rates and endothermic peak integral areas are suitable. Furthermore, the endothermic peak integral areas of Examples 1 and 3, as exemplarily shown, are also suitable in different temperature ranges, indicating that the hydrogel heat-absorbing materials possess excellent heat absorption performance. Simultaneously, the suitable thickness deformation and lack of breakage indicate strong compressive strength. Among these, the hydrogel heat-absorbing materials prepared in Examples 2 and 8-9 exhibit relatively high weight loss rates and endothermic peak integral areas, along with suitable thickness deformation, indicating even superior heat absorption and compressive strength. Therefore, the hydrogel heat-absorbing materials provided in this application possess suitable weight loss rates and endothermic peak integral areas, exhibiting excellent heat absorption and compressive strength, which is beneficial for the encapsulation and use of hydrogel heat-absorbing materials.
[0076] The above description represents the preferred embodiments of this application, but should not be construed as limiting the scope of this application. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this application, and these improvements and modifications are also considered to be within the scope of protection of this application.
Claims
1. A heat-absorbing material, characterized in that, In thermogravimetric analysis tests conducted under an inert gas atmosphere, from 25°C to 200°C, the weight loss rate of the endothermic material was 70%-98%; in the differential scanning calorimetry curve of the endothermic material, the integral area of the endothermic peak in the range of 40°C-200°C was 1200J / g-2300J / g.
2. The heat-absorbing material as described in claim 1, characterized in that, In a thermogravimetric analysis test conducted under an inert gas atmosphere, with temperatures increasing from 25°C to 200°C, the weight loss rate of the heat-absorbing material was 80%-95%.
3. The heat-absorbing material as described in claim 1 or 2, characterized in that, In the differential scanning calorimetry curve of the heat-absorbing material, the integral area of the heat-absorbing peak in the range of 40℃-200℃ is 1650J / g-2000J / g.
4. The heat-absorbing material according to any one of claims 1-3, characterized in that, In the differential scanning calorimetry curve of the heat-absorbing material, the integral area of the endothermic peak in the range of 40℃-80℃ is 72J / g-150J / g; and / or In the differential scanning calorimetry curve of the heat-absorbing material, the integral area of the endothermic peak in the range of 80℃-140℃ is 1100J / g-2070J / g; and / or In the differential scanning calorimetry curve of the heat-absorbing material, the integral area of the heat-absorbing peak in the range of 140℃-200℃ is 100J / g-300J / g.
5. The heat-absorbing material according to any one of claims 1-4, characterized in that, The heat-absorbing material is a hydrogel.
6. The heat-absorbing material according to any one of claims 1-5, characterized in that, In the infrared spectrum of the heat-absorbing material, at 1640 cm⁻¹ -1 -1700cm -1 It has a first infrared absorption peak at 1040 cm⁻¹ -1 -1100cm -1 It has a second infrared absorption peak at 720 cm⁻¹ -1 -930cm -1 It has a third infrared absorption peak at 3352 cm⁻¹ -1 -3382cm -1 It has a fourth infrared absorption peak at 2920 cm⁻¹ -1 -2955cm -1 It has a fifth infrared absorption peak at 1445 cm⁻¹ -1 -1465cm -1 It has a sixth infrared absorption peak.
7. The heat-absorbing material according to any one of claims 1-6, characterized in that, The heat-absorbing material comprises 1 wt%-10 wt% polyacrylamide, 1 wt%-10 wt% sodium polyacrylate, and water.
8. The heat-absorbing material as described in claim 7, characterized in that, The heat-absorbing material also includes at least one of polyacrylic acid, ethylene glycol and glycerin; The content of polyacrylic acid in the heat-absorbing material is less than or equal to 10 wt%; and / or The content of ethylene glycol in the heat-absorbing material is less than or equal to 10 wt%; and / or The content of glycerol in the heat-absorbing material is less than or equal to 20 wt%.
9. The heat-absorbing material according to any one of claims 1-8, characterized in that, The inert gas atmosphere includes at least one of argon, helium, and nitrogen.
10. A method for preparing a heat-absorbing material, characterized in that, The method includes mixing acrylamide, sodium polyacrylate, water, a crosslinking agent, and an initiator to react and obtain the heat-absorbing material according to any one of claims 1-9.
11. The preparation method according to claim 10, characterized in that, The reaction temperature is 50℃-60℃, and the reaction time is 2h-5h.
12. A heat-absorbing element, characterized in that, This includes the heat-absorbing material according to any one of claims 1-9 or the heat-absorbing material prepared by the preparation method according to claim 10 or 11.
13. The heat-absorbing element as described in claim 12, characterized in that, The heat-absorbing component also includes an encapsulation structure, the encapsulation structure having an internal accommodating space, and the heat-absorbing material disposed within the accommodating space.
14. A battery assembly, characterized in that, The battery assembly includes a battery and a heat absorber as described in claim 12 or 13.
15. An electrical appliance, characterized in that, Includes the battery assembly as described in claim 14.