Cooling liquid and preparation method thereof, battery and electric device

Abstract

The invention discloses a cooling liquid and a preparation method thereof, a battery and an electric device. The cooling liquid comprises a cooling solvent and a corrosion inhibitor; wherein the corrosion inhibitor comprises an organic nonionic compound containing a nitrogen heterocyclic ring. The invention relates to the technical field of batteries, in particular to a cooling liquid and a preparation method thereof, a battery and an electric device. Unshared electron pairs of nitrogen atoms in a heterocyclic molecular structure participate in annular conjugation, the electron density of the nitrogen atoms is reduced, coordination of the nitrogen atoms and metal can be achieved, a compact coordination adsorption layer is formed on the outer layer of the metal, then the anti-corrosion effect of the metal, especially the aluminum alloy water cooling plate can be improved, metal corrosion is reduced, scale inhibition is reduced, and the service life of the aluminum alloy water cooling plate is prolonged. The cooling effect of the cooling liquid is improved.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a coolant and a preparation method thereof, a battery and an electrical device. Background Art

[0002] Water cooling technology is the most commonly used battery pack heat conduction and cooling technology for new energy power batteries. It is mainly used to conduct heat generated by the battery during the charging and discharging process, thereby effectively controlling the battery temperature and avoiding thermal runaway.

[0003] Coolant is the most commonly used heat transfer medium in water cooling technology. The conductivity of existing coolants is usually above 3000μS / cm. However, when using existing coolants in power battery cooling systems, the coolant may leak and the coolant conductivity is high, causing the battery to arc and ignite, which may cause the battery to burn and catch fire, leading to safety accidents. Therefore, the coolant used in new energy power batteries needs to focus on reducing the conductivity of the coolant to prevent battery pack combustion accidents caused by coolant leakage.

[0004] However, existing power battery coolants can easily cause metal corrosion and scale generation while reducing electrical conductivity, thus affecting cooling efficiency. Summary of the invention

[0005] The present application is made in view of the above-mentioned problems, and its object is to provide a coolant with low electrical conductivity and not easy to corrode metal.

[0006] In order to achieve the above-mentioned objectives, the embodiments of the present application provide a coolant and a preparation method thereof, a battery and an electrical device.

[0007] In a first aspect, an embodiment of the present application proposes a coolant, comprising a cooling solvent and a corrosion inhibitor; wherein the corrosion inhibitor comprises an organic non-ionic compound containing a nitrogen heterocycle.

[0008] Therefore, in the technical solution of the embodiment of the present application, the electron density of the nitrogen atom is reduced by allowing the unshared electron pairs of the nitrogen atom in the heterocyclic molecular structure to participate in the cyclic conjugation, thereby achieving the coordination of the nitrogen atom with the metal, and forming a dense coordination adsorption layer on the outer layer of the metal, thereby improving the anti-corrosion effect of the metal, especially the aluminum alloy water-cooled plate, reducing the corrosion of the metal, reducing the formation of scale, and improving the cooling effect of the coolant.

[0009] It should be noted that in some embodiments of the present application, the non-ionic compound refers to a compound that does not generate mobile ions when dissolved in a solvent system, such as a covalent compound, which can reduce the conductivity of the coolant.

[0010] In any embodiment, the nitrogen-containing heterocyclic organic non-ionic compound includes at least one of pyridine compounds, imidazole compounds, pyrrole compounds, pyrimidine compounds, purine compounds, triazole compounds and tetrazole compounds. By using at least one of the above nitrogen-containing heterocyclic organic non-ionic compounds, the unshared electron pairs of nitrogen atoms in the heterocyclic molecular structure can further participate in cyclic conjugation, the electron density of nitrogen atoms is reduced, the coordination of nitrogen atoms and metals can be achieved, and a dense coordination adsorption layer is formed on the outer layer of the metal, thereby improving the anti-corrosion effect of metals, especially aluminum alloy water-cooled plates, reducing metal corrosion, reducing scale formation, and improving the cooling effect of the coolant.

[0011] In any embodiment, the pyridine compound includes at least one of pyridine, 2-methylpyridine, 3-methylpyridine, p-nitropyridine, 2-aminopyridine, 2,6-diaminopyridine, 4-ethylpyridine, 4-propylpyridine, 4-pentylpyridine, 4-aminopyridine, 4-benzylpyridine, and 3-benzylpyridine. By using at least one of the above pyridine compounds, the coordination of nitrogen atoms with metals can be further achieved, and a dense coordination adsorption layer can be formed on the outer layer of the metal, thereby improving the anti-corrosion effect of metals, especially aluminum alloy water-cooled plates, reducing metal corrosion, reducing scale formation, and improving the cooling effect of the coolant; and / or,

[0012] The imidazole compound includes at least one of imidazole, 2-methylimidazole, 2-ethylimidazole, 2-phenylimidazole, benzimidazole, 4-phenylimidazole, 4-methylimidazole, 2,2'-biimidazole, 2,4,5-triphenylimidazole, imidazoline, and 2-phenylimidazoline. The use of at least one of the above imidazole compounds can further achieve the coordination of nitrogen atoms and metals, and form a dense coordination adsorption layer on the outer layer of the metal, thereby improving the anti-corrosion effect of metals, especially aluminum alloy water-cooled plates, reducing metal corrosion, reducing scale formation, and improving the cooling effect of the coolant; and / or,

[0013] The pyrrole compound includes at least one of pyrrole, 2-methylpyrrole, 2-ethylpyrrole, 2-nitropyrrole, 2-sulfonic acid pyrrole, 3-methylpyrrole, 3-heptylpyrrole, and 2,5-dimethylpyrrole. By using at least one of the above pyrrole compounds, the coordination of nitrogen atoms with metals can be further achieved, and a dense coordination adsorption layer can be formed on the outer layer of the metal, thereby improving the anti-corrosion effect of metals, especially aluminum alloy water-cooled plates, reducing metal corrosion, reducing scale formation, and improving the cooling effect of the coolant; and / or,

[0014] The pyrimidine compound includes at least one of pyrimidine, 4-aminopyrimidine, 4-methylpyrimidine, 4,6-dimethylpyrimidine, 5-aminopyrimidine, 2,2'-bipyrimidine, and 4,6-dimethoxypyrimidine. The use of at least one of the above pyrimidine compounds can further achieve the coordination of nitrogen atoms with metals, forming a dense coordination adsorption layer on the outer layer of the metal, thereby improving the anti-corrosion effect of metals, especially aluminum alloy water-cooled plates, reducing metal corrosion, reducing scale formation, and improving the cooling effect of the coolant; and / or,

[0015] The purine compound includes at least one of purine, guanine, 7-methylguanine, isoguanine, adenine, 3-methyladenine, and 8-azaguanine. By using at least one of the above purine compounds, the coordination of nitrogen atoms with metals can be further achieved, and a dense coordination adsorption layer can be formed on the outer layer of the metal, thereby improving the anti-corrosion effect of metals, especially aluminum alloy water-cooled plates, reducing metal corrosion, reducing scale formation, and improving the cooling effect of the coolant; and / or,

[0016] The triazole compound includes at least one of 1,2,3-triazole, 1,2,4-triazole, benzotriazole, 3-nitro-1,2,3-triazole, 3-nitro-1,2,3-triazole, 3,5-dimethyl-1,2,4-triazole, and 5-methyl-1-benzotriazole. By using at least one of the above triazole compounds, the coordination of nitrogen atoms with metals can be further achieved, and a dense coordination adsorption layer can be formed on the outer layer of the metal, thereby improving the anti-corrosion effect of metals, especially aluminum alloy water-cooled plates, reducing metal corrosion, reducing scale formation, and improving the cooling effect of the coolant; and / or,

[0017] The tetrazole compounds include at least one of 5-methyltetrazole, 5-benzyl-1H-tetrazole, 5-amino-1H-tetrazole, pentylenetetrazol, tetrazole, 5-(3-pyridyl)-1H-tetrazole, 5-(4-pyridyl)-1H-tetrazole and 5-phenyl-1H-tetrazole. By using at least one of the above tetrazole compounds, the coordination of nitrogen atoms and metals can be further achieved, and a dense coordination adsorption layer can be formed on the outer layer of the metal, thereby improving the anti-corrosion effect of metals, especially aluminum alloy water-cooled plates, reducing metal corrosion, reducing scale formation, and improving the cooling effect of the coolant.

[0018] In any embodiment, the mass proportion of the organic non-ionic compound containing nitrogen heterocycles in the coolant is 0.1% to 2%. Within this range, while reducing metal corrosion, the effect on the viscosity of the coolant can be reduced, thereby reducing the effect on the cooling effect of the coolant. At the same time, the raw material cost of the coolant is reduced. Optionally, the mass proportion of the organic non-ionic compound containing nitrogen heterocycles in the coolant is 0.1% to 1.5%. It is possible to further reduce the effect on the viscosity of the coolant while reducing metal corrosion, thereby reducing the effect on the cooling effect of the coolant, and at the same time reducing the raw material cost of the coolant.

[0019] In any embodiment, the corrosion inhibitor includes a first corrosion inhibitor and a second corrosion inhibitor;

[0020] Wherein, the first corrosion inhibitor comprises an imidazole non-ionic corrosion inhibitor:

[0021] The second corrosion inhibitor includes a pyridine non-ionic corrosion inhibitor.

[0022] By adding two corrosion inhibitors, wherein the first corrosion inhibitor includes an imidazole non-ionic corrosion inhibitor and the second corrosion inhibitor includes a pyridine non-ionic corrosion inhibitor, it is possible to reduce the corrosion to the metal while reducing the generation of H in the coolant during long-term use. + When the coolant generates OH during long-term use, the free imidazole and pyridine in the coolant will combine with H+ to form imidazolium cation / pyridinium cation. - When the imidazolium cation / pyridinium cation reacts with OH - Imidazole / pyridine is formed, which plays a buffering role in adjusting the pH within the appropriate range, reduces the change of the pH value of the coolant, realizes the dynamic regulation of the pH of the coolant, and effectively inhibits the acidification of the system caused by the long-term use of the coolant. In addition, the aqueous solutions of imidazole and pyridine substances are weakly alkaline, so the initial coolant is alkaline, which further reduces the probability of hydrogen evolution corrosion of the metal.

[0023] In any embodiment, the imidazole non-ionic corrosion inhibitor includes at least one of imidazole and 2-methylimidazole. The use of at least one of the imidazole non-ionic corrosion inhibitors can further reduce the corrosion of the metal while generating H in the long-term use of the coolant. + When the coolant generates OH during long-term use, the free imidazole and pyridine in the coolant will combine with H+ to form imidazolium cation / pyridinium cation. -When the imidazole cation / pyridinium cation forms imidazole / pyridine with OH-, it plays a buffering role in adjusting the pH within the appropriate range, reduces the change of the pH value of the coolant, realizes the dynamic regulation of the pH of the coolant, and effectively inhibits the acidification of the system caused by the long-term use of the coolant. In addition, the aqueous solutions of imidazole and pyridine substances are weakly alkaline, so the initial coolant is alkaline, which further reduces the probability of hydrogen evolution corrosion of the metal. It is particularly important to note that the corrosion inhibition effect of 2-methylimidazole is further enhanced due to the presence of hydrophobic methyl groups, and 2-methylimidazole forms a protective surface film on the metal surface. In the protective surface film, the polar pyridine part acts as a hydrophilic polar head facing the metal surface, and the non-polar hydrophobic hydrocarbon chain floats in the coolant, which can block the metal from the coolant as much as possible, thereby inhibiting corrosion. 2-Aminopyridine with two electron donor nitrogen atoms can act as a bidentate ligand to form a chelate complex with metal atoms, which enhances the coordination of the corrosion inhibitor with the metal and enhances the compactness of the adsorption layer. And / or,

[0024] The pyridine nonionic corrosion inhibitor includes at least one of pyridine, 2-aminopyridine, 2,6-diaminopyridine and hexahydropyridine. The use of at least one of the above pyridine nonionic corrosion inhibitors can further reduce the corrosion of the metal while generating H in the long-term use of the coolant. + When the coolant generates OH during long-term use, the free imidazole and pyridine in the coolant will combine with H+ to form imidazolium cation / pyridinium cation. - When the imidazolium cation / pyridinium cation reacts with OH- to form imidazole / pyridine, which in turn plays a buffering role in adjusting the pH within an appropriate range, reducing the change in the pH value of the coolant, and realizing the dynamic regulation of the pH of the coolant, which effectively inhibits the acidification of the system caused by the long-term use of the coolant. In addition, the aqueous solutions of imidazole and pyridine substances are weakly alkaline, so the initial coolant is alkaline, which further reduces the probability of hydrogen evolution corrosion of the metal.

[0025] In any embodiment, the mass ratio of the first corrosion inhibitor to the second corrosion inhibitor is (0.5-8):1; at this mass ratio, the pH value of the buffer solution is adjusted more effectively and the corrosion inhibition effect is better. Optionally, the mass ratio of the first corrosion inhibitor to the second corrosion inhibitor is (1-4):1. The effect of adjusting the pH value of the coolant can be further improved, and the corrosion inhibition effect of the coolant can be improved.

[0026] In any embodiment, the cooling solvent comprises ethylene glycol and water, wherein:

[0027] The purity of the ethylene glycol is greater than 99.9%, which can reduce the conductivity of the coolant; and / or,

[0028] The conductivity of the ethylene glycol is less than 0.1 uS / cm (25° C.), which can reduce the conductivity of the coolant; and / or,

[0029] The water is ultrapure water, which can lower the freezing point of the coolant and improve the cooling effect of the coolant; and / or,

[0030] The conductivity of the water is less than 0.1uS / cm (25°C), which can reduce the conductivity of the coolant; and / or,

[0031] The mass ratio of ethylene glycol to water is (1-10):1. Within this range, the freezing point of the coolant can be reduced and the cooling effect of the coolant can be improved. Optionally, the mass ratio of ethylene glycol to water is (1.13-5.67):1. The freezing and boiling points of the mixed system vary with the mass concentration of ethylene glycol. Within this mass ratio range, the freezing point of the coolant can be further reduced, and the cooling effect of the coolant can be improved, so that the freezing point of the coolant is below -35°C and the boiling point is above 107.5°C.

[0032] In any embodiment, the coolant further comprises an auxiliary agent. Adding the auxiliary agent to the coolant can improve the fluidity of the coolant or make it easier to detect leakage.

[0033] In any embodiment, the auxiliary agent comprises a defoaming agent and a coloring agent, wherein:

[0034] The defoaming agent comprises a polyether-modified polysiloxane compound; and / or,

[0035] The dyeing agent includes an azo dye compound or an anthraquinone dye compound.

[0036] Defoamers can reduce viscosity and eliminate bubbles. Reducing viscosity helps improve coolant fluidity and thus reduce pump energy consumption. Eliminating bubbles helps reduce cavitation corrosion of pumps or water cooling plates caused by bubbles generated during the coolant flow process. Dyes can improve the ability to identify coolant leaks and quickly identify leak risks.

[0037] In any embodiment, the defoamer includes polyether-modified polydimethylsiloxane, and the molecular weight of the polyether-modified polydimethylsiloxane is 10,000 to 30,000. Within this range, the solubility of the polyether-modified polydimethylsiloxane in the coolant can be guaranteed, and the lower surface tension can be taken into account, so as to achieve the defoaming and low-viscosity effects, and have good heat resistance and acid and alkali resistance. Optionally, the molecular weight of the polyether-modified polydimethylsiloxane is 13,000 to 15,000. It can further achieve the defoaming and low-viscosity effects, and have good heat resistance and acid and alkali resistance.

[0038] In any embodiment, in the cooling liquid:

[0039] The mass proportion of the cooling solvent is 97% to 99.7%;

[0040] The mass percentage of the corrosion inhibitor is 0.1% to 2.5%;

[0041] The mass proportion of the defoaming agent is 0.1% to 0.3%;

[0042] The mass proportion of the dye is 0.05% to 0.3%.

[0043] At this mass ratio, the cooling performance can be taken into account and the conductivity of the coolant can be reduced. At the same time, the viscosity of the coolant can be reduced and the ability to identify coolant leaks can be improved.

[0044] In a second aspect, an embodiment of the present application provides a method for preparing a coolant, which is used to prepare the coolant of the first aspect of the present application, comprising the following steps:

[0045] The cooling solvent and the corrosion inhibitor are mixed to obtain a cooling liquid.

[0046] By adding corrosion inhibitors to the coolant, the unshared electron pairs of nitrogen atoms in the heterocyclic molecular structure participate in cyclic conjugation, and the electron density of nitrogen atoms is reduced, so that the coordination of nitrogen atoms and metals can be achieved, and a dense coordination adsorption layer can be formed on the outer layer of the metal, thereby improving the anti-corrosion effect of metals, especially aluminum alloy water-cooled plates, reducing metal corrosion, reducing scale formation, and improving the cooling effect of the coolant.

[0047] In any embodiment, the step of "mixing the cooling solvent with the corrosion inhibitor to obtain a cooling liquid" comprises:

[0048] Mix ethylene glycol with water to obtain a cooling solvent;

[0049] Mixing the first corrosion inhibitor with the second corrosion inhibitor to obtain a corrosion inhibitor;

[0050] Mixing the corrosion inhibitor with the cooling solvent to obtain a premixed solution;

[0051] The premixed solution is mixed with the defoaming agent and the coloring agent to obtain a cooling liquid;

[0052] Wherein, the first corrosion inhibitor comprises an imidazole non-ionic corrosion inhibitor:

[0053] The second corrosion inhibitor includes a pyridine non-ionic corrosion inhibitor.

[0054] By adding two corrosion inhibitors, wherein the first corrosion inhibitor includes an imidazole non-ionic corrosion inhibitor and the second corrosion inhibitor includes a pyridine non-ionic corrosion inhibitor, it is possible to reduce the corrosion to the metal while reducing the generation of H in the coolant during long-term use. + When the free imidazole and pyridine in the coolant react with H +Combined to form imidazolium cation / pyridinium cation. When the coolant generates OH during long-term use - When the imidazolium cation / pyridinium cation reacts with OH - Imidazole / pyridine is formed, which plays a buffering role in adjusting the pH within the appropriate range, reduces the change of the pH value of the coolant, realizes the dynamic regulation of the pH of the coolant, and effectively inhibits the acidification of the system caused by the long-term use of the coolant. In addition, the aqueous solutions of imidazole and pyridine substances are weakly alkaline, so the initial coolant will not be acidic, further reducing the probability of hydrogen evolution corrosion of the metal.

[0055] In a third aspect, an embodiment of the present application provides a battery, wherein the battery includes a battery body and a cooling system, wherein the cooling system includes the cooling liquid of the first aspect of the present application or a cooling liquid prepared by the method for preparing the cooling liquid of the second aspect of the present application.

[0056] In a fourth aspect, an embodiment of the present application provides an electrical device, comprising the battery of the third aspect of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 is a schematic diagram of a secondary battery according to one embodiment of the present application.

[0058] Figure 2 yes Figure 2 An exploded view of a secondary battery according to an embodiment of the present application is shown.

[0059] Figure 3 is a schematic diagram of a battery module according to an embodiment of the present application.

[0060] Figure 4 It is a schematic diagram of a battery pack according to one embodiment of the present application.

[0061] Figure 5 yes Figure 4 An exploded view of a battery pack according to an embodiment of the present application is shown.

[0062] Figure 6 FIG. 1 is a schematic diagram of an electric device using a secondary battery according to an embodiment of the present application as a power source.

[0063] Description of reference numerals:

[0064] 1 battery pack; 2 upper box; 3 lower box; 4 battery module; 5 secondary battery; 51 shell; 52 electrode assembly; 53 top cover assembly; 54 coolant; 541 coating in the middle area; 542 coating in the edge area; 543 solid electrolyte membrane; 544 oxidant membrane layer; 55 pole piece assembly; 551 pole piece; 552 isolation membrane; 56 pole ear. DETAILED DESCRIPTION

[0065] The following specifically discloses the implementation methods of the coolant and its preparation method, battery and electrical device of the present application. However, there may be cases where unnecessary detailed descriptions are omitted. For example, there are cases where detailed descriptions of well-known matters and repeated descriptions of actually the same structure are omitted. This is to avoid the following description from becoming unnecessarily lengthy and to facilitate the understanding of those skilled in the art. In addition, the drawings and the following description are provided for those skilled in the art to fully understand the present application and are not intended to limit the subject matter described in the claims.

[0066] "Scope" disclosed in the present application is limited in the form of lower limit and upper limit, and a given range is limited by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundary of a special range. The scope limited in this way can be including end values ​​or not including end values, and can be arbitrarily combined, that is, any lower limit can be combined with any upper limit to form a scope. For example, if the scope of 60-120 and 80-110 is listed for a specific parameter, it is understood that the scope of 60-110 and 80-120 is also expected. In addition, if the minimum range values ​​1 and 2 are listed, and if the maximum range values ​​3, 4 and 5 are listed, the following scope can be all expected: 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5. In the present application, unless otherwise specified, the numerical range "ab" represents the abbreviation of any real number combination between a and b, wherein a and b are real numbers. For example, the numerical range "0-5" means that all real numbers between "0-5" are listed in this document, and "0-5" is just an abbreviation of these numerical combinations. In addition, when a parameter is expressed as an integer ≥ 2, it is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0067] Unless otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution.

[0068] Unless otherwise specified, all technical features and optional technical features of this application can be combined with each other to form a new technical solution.

[0069] If there is no special explanation, all steps of the present application can be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), which means that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially. For example, the method may further include step (c), which means that step (c) may be added to the method in any order. For example, the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc.

[0070] Water cooling technology is the most commonly used battery pack heat conduction and cooling technology for new energy power batteries. It is mainly used to conduct heat generated by the battery during the charging and discharging process, thereby effectively controlling the battery temperature and avoiding thermal runaway.

[0071] Coolant is the most commonly used heat transfer medium in water cooling technology. The conductivity of existing coolants is usually above 3000μS / cm. However, when using existing coolants in power battery cooling systems, the coolant may leak and the coolant conductivity is high, causing the battery to arc and ignite, which may cause the battery to burn and catch fire, leading to safety accidents. Therefore, the coolant used in new energy power batteries needs to focus on reducing the conductivity of the coolant to prevent battery pack combustion accidents caused by coolant leakage.

[0072] However, existing power battery coolants can easily cause metal corrosion and scale generation while reducing electrical conductivity, thus affecting cooling efficiency.

[0073] Therefore, there are endless studies on reducing metal corrosion of coolants, for example, a low-conductivity hydrogen fuel cell coolant with metal corrosion inhibition performance and a preparation method thereof. The coolant is composed of water, ethylene glycol, corrosion inhibitor, metal chelator, and pigment. The synergistic slow release effect of metal corrosion inhibitor and metal chelator / stabilizer improves the corrosion inhibition efficiency of metals. In addition, compared with existing products, the low-conductivity coolant solution provided by this solution has a conductivity of less than 0.50μS / cm, a higher pH and reserve alkalinity, and has better steel and aluminum metal corrosion inhibition performance. It may cause the pH of the coolant to continue to decrease during use, and eventually become completely acidic, which in turn accelerates metal corrosion and produces a large amount of scale adhesion, affecting heat transfer.

[0074] Surprisingly, adding nitrogen-containing heterocyclic nonionic compounds to the coolant can reduce metal corrosion and reduce scale formation.

[0075] Based on this, the present application provides a coolant and a preparation method thereof, a battery and an electrical device.

[0076] In a first aspect, an embodiment of the present application proposes a coolant, comprising a cooling solvent and a corrosion inhibitor; wherein the corrosion inhibitor comprises an organic non-ionic compound containing a nitrogen heterocycle.

[0077] Therefore, in the technical solution of the embodiment of the present application, the electron density of the nitrogen atom is reduced by allowing the unshared electron pairs of the nitrogen atom in the heterocyclic molecular structure to participate in the cyclic conjugation, thereby achieving the coordination of the nitrogen atom with the metal, and forming a dense coordination adsorption layer on the outer layer of the metal, thereby improving the anti-corrosion effect of the metal, especially the aluminum alloy water-cooled plate, reducing the corrosion of the metal, reducing the formation of scale, and improving the cooling effect of the coolant.

[0078] It should be noted that in some embodiments of the present application, the non-ionic compound refers to a compound that does not generate mobile ions when dissolved in a solvent system, such as a covalent compound, which can reduce the conductivity of the coolant.

[0079] In any embodiment, the nitrogen-containing heterocyclic organic non-ionic compound includes at least one of pyridine compounds, imidazole compounds, pyrrole compounds, pyrimidine compounds, purine compounds, triazole compounds and tetrazole compounds. By using at least one of the above nitrogen-containing heterocyclic organic non-ionic compounds, the unshared electron pairs of nitrogen atoms in the heterocyclic molecular structure can further participate in cyclic conjugation, the electron density of nitrogen atoms is reduced, the coordination of nitrogen atoms and metals can be achieved, and a dense coordination adsorption layer is formed on the outer layer of the metal, thereby improving the anti-corrosion effect of metals, especially aluminum alloy water-cooled plates, reducing metal corrosion, reducing scale formation, and improving the cooling effect of the coolant.

[0080] In any embodiment, the pyridine compound includes at least one of pyridine, 2-methylpyridine, 3-methylpyridine, p-nitropyridine, 2-aminopyridine, 2,6-diaminopyridine, 4-ethylpyridine, 4-propylpyridine, 4-pentylpyridine, 4-aminopyridine, 4-benzylpyridine, and 3-benzylpyridine. By using at least one of the above pyridine compounds, the coordination of nitrogen atoms and metals can be further achieved, and a dense coordination adsorption layer can be formed on the outer layer of the metal, thereby improving the anti-corrosion effect of metals, especially aluminum alloy water-cooled plates, reducing metal corrosion, reducing scale formation, and improving the cooling effect of the coolant.

[0081] The imidazole compound includes at least one of imidazole, 2-methylimidazole, 2-ethylimidazole, 2-phenylimidazole, benzimidazole, 4-phenylimidazole, 4-methylimidazole, 2,2'-biimidazole, 2,4,5-triphenylimidazole, imidazoline, and 2-phenylimidazoline. By using at least one of the above imidazole compounds, the coordination of nitrogen atoms and metals can be further achieved, and a dense coordination adsorption layer can be formed on the outer layer of the metal, thereby improving the anti-corrosion effect of metals, especially aluminum alloy water-cooled plates, reducing metal corrosion, reducing scale formation, and improving the cooling effect of the coolant.

[0082] The pyrrole compound includes at least one of pyrrole, 2-methylpyrrole, 2-ethylpyrrole, 2-nitropyrrole, 2-sulfonic acid pyrrole, 3-methylpyrrole, 3-heptylpyrrole, and 2,5-dimethylpyrrole. By using at least one of the above pyrrole compounds, the coordination of nitrogen atoms and metals can be further achieved, and a dense coordination adsorption layer can be formed on the outer layer of the metal, thereby improving the anti-corrosion effect of metals, especially aluminum alloy water-cooled plates, reducing metal corrosion, reducing scale formation, and improving the cooling effect of the coolant.

[0083] The pyrimidine compounds include at least one of pyrimidine, 4-aminopyrimidine, 4-methylpyrimidine, 4,6-dimethylpyrimidine, 5-aminopyrimidine, 2,2'-bipyrimidine, and 4,6-dimethoxypyrimidine. By using at least one of the above pyrimidine compounds, the coordination of nitrogen atoms and metals can be further achieved, and a dense coordination adsorption layer can be formed on the outer layer of the metal, thereby improving the anti-corrosion effect of metals, especially aluminum alloy water-cooled plates, reducing metal corrosion, reducing scale formation, and improving the cooling effect of the coolant.

[0084] The purine compounds include at least one of purine, guanine, 7-methylguanine, isoguanine, adenine, 3-methyladenine, and 8-azaguanine. By using at least one of the above purine compounds, the coordination of nitrogen atoms and metals can be further achieved, and a dense coordination adsorption layer can be formed on the outer layer of the metal, thereby improving the anti-corrosion effect of metals, especially aluminum alloy water-cooled plates, reducing metal corrosion, reducing scale formation, and improving the cooling effect of the coolant.

[0085] The triazole compound includes at least one of 1,2,3-triazole, 1,2,4-triazole, benzotriazole, 3-nitro-1,2,3-triazole, 3-nitro-1,2,3-triazole, 3,5-dimethyl-1,2,4-triazole, and 5-methyl-1-benzotriazole. By using at least one of the above triazole compounds, the coordination of nitrogen atoms and metals can be further achieved, and a dense coordination adsorption layer can be formed on the outer layer of the metal, thereby improving the anti-corrosion effect of metals, especially aluminum alloy water-cooled plates, reducing metal corrosion, reducing scale formation, and improving the cooling effect of the coolant.

[0086] The tetrazole compounds include at least one of 5-methyltetrazole, 5-benzyl-1H-tetrazole, 5-amino-1H-tetrazole, pentylenetetrazol, tetrazole, 5-(3-pyridyl)-1H-tetrazole, 5-(4-pyridyl)-1H-tetrazole and 5-phenyl-1H-tetrazole. By using at least one of the above tetrazole compounds, the coordination of nitrogen atoms and metals can be further achieved, and a dense coordination adsorption layer can be formed on the outer layer of the metal, thereby improving the anti-corrosion effect of metals, especially aluminum alloy water-cooled plates, reducing metal corrosion, reducing scale formation, and improving the cooling effect of the coolant.

[0087] It should be noted that the specific selection of the types of the above-mentioned pyridine compounds, imidazole compounds, pyrrole compounds, pyrimidine compounds, purine compounds, triazole compounds and tetrazole compounds can be set simultaneously or separately. When set simultaneously, the coordination of nitrogen atoms and metals can be further realized to form a dense coordination adsorption layer on the outer layer of the metal, thereby improving the anti-corrosion effect of metals, especially aluminum alloy water-cooled plates, reducing metal corrosion, reducing scale formation, and improving the cooling effect of the coolant.

[0088] In any embodiment, the mass proportion of the organic non-ionic compound containing nitrogen heterocycles in the coolant is 0.1% to 2%. Within this range, while reducing metal corrosion, the effect on the viscosity of the coolant can be reduced, thereby reducing the effect on the cooling effect of the coolant. At the same time, the raw material cost of the coolant is reduced. Optionally, the mass proportion of the organic non-ionic compound containing nitrogen heterocycles in the coolant is 0.1% to 1.5%. It is possible to further reduce the effect on the viscosity of the coolant while reducing metal corrosion, thereby reducing the effect on the cooling effect of the coolant. At the same time, the raw material cost of the coolant is reduced.

[0089] In any embodiment, the corrosion inhibitor includes a first corrosion inhibitor and a second corrosion inhibitor; wherein the first corrosion inhibitor includes an imidazole non-ionic corrosion inhibitor; and the second corrosion inhibitor includes a pyridine non-ionic corrosion inhibitor.

[0090] By adding two corrosion inhibitors, wherein the first corrosion inhibitor includes an imidazole non-ionic corrosion inhibitor and the second corrosion inhibitor includes a pyridine non-ionic corrosion inhibitor, it is possible to reduce the corrosion to the metal while reducing the generation of H in the coolant during long-term use. + When the free imidazole and pyridine in the coolant react with H + Combined to form imidazolium cation / pyridinium cation. When the coolant generates OH during long-term use - When the imidazolium cation / pyridinium cation reacts with OH - Imidazole / pyridine is formed, which plays a buffering role in adjusting the pH within the appropriate range, reduces the change of the pH value of the coolant, realizes the dynamic regulation of the pH of the coolant, and effectively inhibits the acidification of the system caused by the long-term use of the coolant. In addition, the aqueous solutions of imidazole and pyridine substances are weakly alkaline, so the initial coolant is alkaline, which further reduces the probability of hydrogen evolution corrosion of the metal.

[0091] In any embodiment, the imidazole non-ionic corrosion inhibitor includes at least one of imidazole and 2-methylimidazole. The use of at least one of the imidazole non-ionic corrosion inhibitors can further reduce the corrosion of the metal while generating H in the long-term use of the coolant. + When the free imidazole and pyridine in the coolant react with H+ Combined to form imidazolium cation / pyridinium cation. When the coolant generates OH during long-term use - When the imidazolium cation / pyridinium cation reacts with OH - Imidazole / pyridine is formed, which plays a buffering role in adjusting the pH within a suitable range, reduces the change of the pH value of the coolant, realizes the dynamic regulation of the pH of the coolant, and effectively inhibits the acidification of the system caused by the long-term use of the coolant. In addition, the aqueous solutions of imidazole and pyridine substances are weakly alkaline, so the initial coolant is alkaline, which further reduces the probability of hydrogen evolution corrosion of the metal. It is particularly important to note that the corrosion inhibition effect of 2-methylimidazole is further enhanced due to the presence of hydrophobic methyl groups, and 2-methylimidazole forms a protective surface film on the metal surface. In the protective surface film, the polar pyridine part acts as a hydrophilic polar head facing the metal surface, and the non-polar hydrophobic hydrocarbon chain floats in the coolant, which can block the metal of the coolant and the metal as much as possible, thereby inhibiting corrosion. 2-aminopyridine with two electron donor nitrogen atoms can form a chelate complex with metal atoms as a bidentate ligand, which enhances the coordination of the corrosion inhibitor with the metal and enhances the tightness of the adsorption layer.

[0092] The pyridine nonionic corrosion inhibitor includes at least one of pyridine, 2-aminopyridine, 2,6-diaminopyridine and hexahydropyridine. The use of at least one of the above pyridine nonionic corrosion inhibitors can further reduce the corrosion of the metal while generating H in the long-term use of the coolant. + When the free imidazole and pyridine in the coolant react with H + Combined to form imidazolium cation / pyridinium cation. When the coolant generates OH during long-term use - When the imidazolium cation / pyridinium cation reacts with OH - Imidazole / pyridine is formed, which plays a buffering role in adjusting the pH within the appropriate range, reduces the change of the pH value of the coolant, realizes the dynamic regulation of the pH of the coolant, and effectively inhibits the acidification of the system caused by the long-term use of the coolant. In addition, the aqueous solutions of imidazole and pyridine substances are weakly alkaline, so the initial coolant is alkaline, which further reduces the probability of hydrogen evolution corrosion of the metal.

[0093] It should be noted that the above-mentioned imidazole non-ionic corrosion inhibitor and pyridine non-ionic corrosion inhibitor can be set simultaneously or separately. When set simultaneously, the pH value of the coolant can be further adjusted to reduce corrosion to the metal.

[0094] In any embodiment, the mass ratio of the first corrosion inhibitor to the second corrosion inhibitor is (0.5-8):1; at this mass ratio, the pH value of the buffer solution is adjusted better and the corrosion inhibition effect is better. Optionally, the mass ratio of the first corrosion inhibitor to the second corrosion inhibitor may be, but is not limited to, 0.5:1, 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1 or 8:1. The mass ratio of the first corrosion inhibitor to the second corrosion inhibitor is (1-4):1. The effect of adjusting the pH value of the coolant can be further improved, and the corrosion inhibition effect of the coolant can be improved.

[0095] In any embodiment, the cooling solvent includes ethylene glycol and water, wherein the purity of the ethylene glycol is greater than 99.9%, which can reduce the conductivity of the cooling liquid.

[0096] In any embodiment, the cooling solvent includes ethylene glycol and water, wherein the conductivity of the ethylene glycol is less than 0.1 uS / cm (25° C.), which can reduce the conductivity of the cooling liquid.

[0097] In any embodiment, the cooling solvent includes ethylene glycol and water, wherein the water is ultrapure water, which can lower the freezing point of the coolant and improve the cooling effect of the coolant.

[0098] In any embodiment, the cooling solvent includes ethylene glycol and water, wherein the conductivity of the water is less than 0.1 uS / cm (25° C.), which can reduce the conductivity of the cooling liquid.

[0099] In any embodiment, the cooling solvent includes ethylene glycol and water, wherein the mass ratio of ethylene glycol to water is (1 to 10): 1. Within this range, the freezing point of the coolant can be reduced and the cooling effect of the coolant can be improved. The mass ratio of ethylene glycol to water can be, but is not limited to, 1: 1, 1.13: 1, 2: 1, 3: 1, 4: 1, 5: 1, 5.67: 1, 6: 1, 7: 1, 8: 1, 9: 1 or 10: 1. Optionally, the mass ratio of ethylene glycol to water is (1.13 to 5.67): 1, and the ice-boiling point of the mixed system varies with the mass concentration of ethylene glycol. Within this mass ratio range, the freezing point of the coolant can be further reduced, and the cooling effect of the coolant can be improved, so that the freezing point of the coolant is below -35°C and the boiling point is above 107.5°C.

[0100] It should be noted that the purity of ethylene glycol, electrical conductivity of ethylene glycol, electrical conductivity of water, purity of water, and mass ratio of ethylene glycol to water can be set simultaneously or separately. When set simultaneously, the electrical conductivity of the coolant can be further reduced and the cooling effect can be improved.

[0101] In any embodiment, the coolant further comprises an auxiliary agent. Adding the auxiliary agent to the coolant can improve the fluidity of the coolant or make it easier to detect leakage.

[0102] In any embodiment, the auxiliary agent includes a defoaming agent and a coloring agent, wherein: the defoaming agent includes a polyether-modified polysiloxane compound.

[0103] In any embodiment, the auxiliary agent includes a defoaming agent and a dye, wherein: the dye includes an azo dye compound or an anthraquinone dye compound.

[0104] Defoamers can reduce viscosity and eliminate bubbles. Reducing viscosity helps improve coolant fluidity and thus reduce pump energy consumption. Eliminating bubbles helps reduce cavitation corrosion of pumps or water cooling plates caused by bubbles generated during the coolant flow process. Dyes can improve the ability to identify coolant leaks and quickly identify leak risks.

[0105] It should be noted that the above-mentioned defoaming agent and dye can be set at the same time or separately. When set at the same time, the ability to identify coolant leakage can be further improved, the risk of leakage can be quickly identified, and cavitation corrosion can be reduced.

[0106] In any embodiment, the defoamer includes polyether-modified polydimethylsiloxane, and the molecular weight of the polyether-modified polydimethylsiloxane is 10000-30000. Within this range, the solubility of the polyether-modified polydimethylsiloxane in the coolant can be guaranteed, and the lower surface tension can be taken into account, so as to achieve the defoaming and low-viscosity effects while having good heat resistance and acid and alkali resistance. The molecular weight of the polyether-modified polydimethylsiloxane can be, but is not limited to, 10000, 13000, 14000, 15000, 18000, 20000, 22000, 25000, 28000 or 30000. Optionally, the molecular weight of the polyether-modified polydimethylsiloxane is 13000-15000. It can further achieve the defoaming and low-viscosity effects while having good heat resistance and acid and alkali resistance.

[0107] In any embodiment, in the cooling liquid:

[0108] The mass proportion of the cooling solvent is 97% to 99.7%; the mass proportion of the cooling solvent may be but is not limited to 97%, 97.5%, 98%, 98.5%, 99%, 99.5% or 99.7%.

[0109] The mass proportion of the corrosion inhibitor is 0.1% to 2.5%; the mass proportion of the corrosion inhibitor can be but is not limited to 0.1%, 0.2%, 0.5%, 0.8%, 1%, 1.2%, 1.5%, 1.8%, 2%, 2.2% or 2.5%.

[0110] The mass proportion of the defoaming agent is 0.1% to 0.3%; the mass proportion of the defoaming agent may be but is not limited to 0.1%, 0.15%, 0.2%, 0.25% or 0.3%.

[0111] The mass proportion of the dye is 0.05% to 0.3%. The mass proportion of the dye can be but is not limited to 0.05%, 0.1%, 0.15%, 0.2%, 0.25% or 0.3%.

[0112] At this mass ratio, the cooling performance can be taken into account and the conductivity of the coolant can be reduced. At the same time, the viscosity of the coolant can be reduced and the ability to identify coolant leaks can be improved.

[0113] In a second aspect, an embodiment of the present application provides a method for preparing a coolant, which is used to prepare the coolant of the first aspect of the present application, comprising the following steps:

[0114] The cooling solvent and the corrosion inhibitor are mixed to obtain a cooling liquid.

[0115] By adding corrosion inhibitors to the coolant, the unshared electron pairs of nitrogen atoms in the heterocyclic molecular structure participate in cyclic conjugation, and the electron density of nitrogen atoms is reduced, so that the coordination of nitrogen atoms and metals can be achieved, and a dense coordination adsorption layer can be formed on the outer layer of the metal, thereby improving the anti-corrosion effect of metals, especially aluminum alloy water-cooled plates, reducing metal corrosion, reducing scale formation, and improving the cooling effect of the coolant.

[0116] In any embodiment, the step of "mixing the cooling solvent with the corrosion inhibitor to obtain a cooling liquid" comprises:

[0117] Mix ethylene glycol with water to obtain a cooling solvent;

[0118] Mixing the first corrosion inhibitor with the second corrosion inhibitor to obtain a corrosion inhibitor;

[0119] Mixing the corrosion inhibitor with the cooling solvent to obtain a premixed solution;

[0120] The premixed solution is mixed with the defoaming agent and the coloring agent to obtain a cooling liquid;

[0121] Wherein, the first corrosion inhibitor comprises an imidazole non-ionic corrosion inhibitor:

[0122] The second corrosion inhibitor includes a pyridine non-ionic corrosion inhibitor.

[0123] By adding two corrosion inhibitors, wherein the first corrosion inhibitor includes an imidazole non-ionic corrosion inhibitor and the second corrosion inhibitor includes a pyridine non-ionic corrosion inhibitor, it is possible to reduce the corrosion to the metal while reducing the generation of H in the coolant during long-term use. + When the free imidazole and pyridine in the coolant react with H +Combined to form imidazolium cation / pyridinium cation. When the coolant generates OH during long-term use - When the imidazolium cation / pyridinium cation reacts with OH - Imidazole / pyridine is formed, which plays a buffering role in adjusting the pH within the appropriate range, reduces the change of the pH value of the coolant, realizes the dynamic regulation of the pH of the coolant, and effectively inhibits the acidification of the system caused by the long-term use of the coolant. In addition, the aqueous solutions of imidazole and pyridine substances are weakly alkaline, so the initial coolant will not be acidic, further reducing the probability of hydrogen evolution corrosion of the metal.

[0124] In a third aspect, an embodiment of the present application provides a battery, wherein the battery includes a battery body and a cooling system, wherein the cooling system includes the cooling liquid of the first aspect of the present application or the cooling liquid prepared by the cooling preparation method of the second aspect of the present application.

[0125] In any embodiment, the battery comprises a lithium ion battery.

[0126] In any embodiment, the battery comprises a primary battery or a secondary battery.

[0127] In one embodiment of the present application, a secondary battery is provided. Generally, the secondary battery includes a positive electrode sheet, a negative electrode sheet, an electrolyte and a separator. During the battery charging and discharging process, active ions are embedded and released back and forth between the positive electrode sheet and the negative electrode sheet. The electrolyte plays the role of conducting ions between the positive electrode sheet and the negative electrode sheet. The separator is arranged between the positive electrode sheet and the negative electrode sheet, mainly to prevent the positive and negative electrodes from short-circuiting, while allowing ions to pass through.

[0128] The positive electrode sheet includes a positive electrode current collector and a positive electrode film layer arranged on at least one surface of the positive electrode current collector.

[0129] As an example, the positive electrode current collector has two surfaces opposite to each other in its thickness direction, and the positive electrode film layer is disposed on any one or both of the two opposite surfaces of the positive electrode current collector.

[0130] In some embodiments, the positive electrode current collector may be a metal foil or a composite current collector. For example, aluminum foil may be used as the metal foil. The composite current collector may include a polymer material base and a metal layer formed on at least one surface of the polymer material base. The composite current collector may be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0131] In some embodiments, the positive electrode active material may adopt a positive electrode active material for lithium ion batteries known in the art. As an example, the positive electrode active material may include at least one of the following materials: a lithium-containing phosphate with an olivine structure, a lithium transition metal oxide, and their respective modified compounds. However, the present application is not limited to these materials, and other traditional materials that can be used as positive electrode active materials for batteries may also be used. These positive electrode active materials may be used alone or in combination of two or more. Among them, examples of lithium transition metal oxides may include, but are not limited to, lithium cobalt oxides (such as LiCoO 2 ), lithium nickel oxide (such as LiNiO 2 ), lithium manganese oxide (such as LiMnO 2 、LiMn 2 O 4 ), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (such as LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O 2 (Also referred to as NCM 333 )、LiNi 0.5 Co 0.2 Mn 0.3 O 2 (Also referred to as NCM 523 )、LiNi 0.5 Co 0.25 Mn 0.25 O 2 (Also referred to as NCM 211 )、LiNi 0.6 Co 0.2 Mn 0.2 O 2 (Also referred to as NCM 622 )、LiNi 0.8 Co 0.1 Mn 0.1 O 2 (Also referred to as NCM 811 ), lithium nickel cobalt aluminum oxide (such as LiNi 0.85 Co 0.15 Al 0.05 O 2 ) and its modified compounds, etc. Examples of lithium phosphates containing olivine structures may include, but are not limited to, lithium iron phosphate (such as LiFePO 4 (also referred to as LFP), composite materials of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO 4 ), at least one of a composite material of lithium manganese phosphate and carbon, a composite material of lithium iron manganese phosphate, and a composite material of lithium iron manganese phosphate and carbon.

[0132] In some embodiments, the positive electrode film layer further includes a binder. As an example, the binder may include at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorine-containing acrylate resin.

[0133] In some embodiments, the positive electrode film layer further includes a conductive agent. As an example, the conductive agent may include at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0134] In some embodiments, the positive electrode sheet can be prepared in the following manner: the components for preparing the positive electrode sheet, such as the positive electrode active material, the conductive agent, the binder and any other components are dispersed in a solvent (such as N-methylpyrrolidone) to form a positive electrode slurry; the positive electrode slurry is coated on the positive electrode sheet structure, and after drying, cold pressing and other processes, the positive electrode sheet can be obtained.

[0135] The negative electrode sheet includes a positive electrode current collector and a negative electrode film layer disposed on at least one surface of the positive electrode current collector, wherein the negative electrode film layer includes a negative electrode active material.

[0136] As an example, the negative electrode sheet structure includes a negative electrode current collector having two surfaces opposite to each other in its own thickness direction, and the negative electrode film layer is disposed on any one or both of the two opposite surfaces of the negative electrode current collector structure.

[0137] In some embodiments, the negative electrode current collector may be a metal foil or a composite current collector. For example, as the metal foil, a copper foil may be used. The composite current collector may include a polymer material base layer and a metal layer formed on at least one surface of the polymer material substrate. The composite current collector may be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0138] In some embodiments, the negative electrode active material may adopt the negative electrode active material for the battery known in the art. As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, lithium titanate, etc. The silicon-based material may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. The tin-based material may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, the present application is not limited to these materials, and other traditional materials that can be used as negative electrode active materials for batteries may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0139] In some embodiments, the negative electrode film layer further includes a binder. The binder may be selected from at least one of styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA) and carboxymethyl chitosan (CMCS).

[0140] In some embodiments, the negative electrode film layer further includes a conductive agent, which can be selected from at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene and carbon nanofibers.

[0141] In some embodiments, the negative electrode film layer further includes other additives, such as a thickener (eg, sodium carboxymethyl cellulose (CMC-Na)).

[0142] In some embodiments, the negative electrode sheet can be prepared in the following manner: the above-mentioned components for preparing the negative electrode sheet, such as the negative electrode active material, the conductive agent, the binder and any other components are dispersed in a solvent (such as deionized water) to form a negative electrode slurry; the negative electrode slurry is coated on the negative electrode sheet structure, and after drying, cold pressing and other processes, the negative electrode sheet can be obtained.

[0143] The electrolyte plays the role of conducting ions between the positive electrode and the negative electrode. The present application has no specific restrictions on the type of electrolyte, which can be selected according to needs. For example, the electrolyte can be liquid, gel or all-solid.

[0144] In some embodiments, the electrolyte is an electrolyte solution, which includes an electrolyte salt and a solvent.

[0145] In some embodiments, the electrolyte salt can be selected from at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalatoborate, lithium dioxalatoborate, lithium difluorodioxalatophosphate, and lithium tetrafluorooxalatophosphate.

[0146] In some embodiments, the solvent can be selected from at least one of ethylene carbonate, propylene carbonate, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, cyclopentane sulfone, dimethyl sulfone, methyl ethyl sulfone and diethyl sulfone.

[0147] In some embodiments, the electrolyte may further include additives, such as negative electrode film-forming additives, positive electrode film-forming additives, and additives that can improve certain battery properties, such as additives that improve battery overcharge performance, additives that improve battery high or low temperature performance, etc.

[0148] In some embodiments, the electrolyte may also include a solid electrolyte disposed in a coating in an edge region of the pole piece, forming the pole piece structure of the first aspect of the present application.

[0149] In some embodiments, the electrolyte may further include a solid electrolyte membrane disposed in the edge region of the pole piece to form the pole piece structure of the first aspect of the present application or the pole piece assembly of the second aspect of the present application.

[0150] In some embodiments of the present application, the pole piece structure may be a positive pole piece structure; in some embodiments of the present application, the pole piece structure may be a negative pole piece structure; in some embodiments of the present application, the pole piece structure may be both a positive pole piece structure and a negative pole piece structure.

[0151] In some embodiments, the secondary battery further includes a separator. The present application has no particular limitation on the type of separator, and any known porous separator with good chemical stability and mechanical stability can be selected.

[0152] In some embodiments, the material of the isolation membrane can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene and polyvinylidene fluoride. The isolation membrane can be a single-layer film or a multi-layer composite film, without particular limitation. When the isolation membrane is a multi-layer composite film, the materials of each layer can be the same or different, without particular limitation.

[0153] In some embodiments, the positive electrode sheet, the negative electrode sheet, and the separator may be formed into an electrode assembly by a winding process or a lamination process.

[0154] In some embodiments, the secondary battery may include an outer package, which may be used to encapsulate the electrode assembly and the electrolyte.

[0155] In some embodiments, the outer packaging of the secondary battery may be a hard shell, such as a hard plastic shell, an aluminum shell, a steel shell, etc. The outer packaging of the secondary battery may also be a soft package, such as a bag-type soft package. The material of the soft package may be plastic, and examples of the plastic include polypropylene, polybutylene terephthalate, and polybutylene succinate.

[0156] The present application has no particular limitation on the shape of the secondary battery, which may be cylindrical, square or any other shape. Figure 1 The secondary battery 5 is a square structure as an example.

[0157] In some embodiments, reference Figure 2 , the outer package may include a shell 51 and a cover plate 53. Among them, the shell 51 may include a bottom plate and a side plate connected to the bottom plate, and the bottom plate and the side plate enclose a receiving cavity. The shell 51 has an opening connected to the receiving cavity, and the cover plate 53 can be covered on the opening to close the receiving cavity. The positive electrode sheet, the negative electrode sheet and the isolation membrane can form an electrode assembly 52 through a winding process or a lamination process. The electrode assembly 52 is encapsulated in the receiving cavity. The electrolyte is infiltrated in the electrode assembly 52. ​​The number of electrode assemblies 52 contained in the secondary battery 5 can be one or more, and those skilled in the art can select according to specific actual needs.

[0158] In some embodiments, secondary batteries may be assembled into a battery module. The number of secondary batteries contained in the battery module may be one or more, and the specific number may be selected by those skilled in the art according to the application and capacity of the battery module.

[0159] Figure 3 4 is an example of a battery module. Figure 3 In the battery module 4, the plurality of secondary batteries 5 may be arranged in sequence along the length direction of the battery module 4. Of course, they may also be arranged in any other manner. Further, the plurality of secondary batteries 5 may be fixed by fasteners.

[0160] Optionally, the battery module 4 may further include a housing having a receiving space, and the plurality of secondary batteries 5 are received in the receiving space.

[0161] In some embodiments, the battery modules described above may also be assembled into a battery pack. The battery pack may contain one or more battery modules, and the specific number may be selected by those skilled in the art according to the application and capacity of the battery pack.

[0162] Figure 4 and Figure 5 1 is a battery pack 1 as an example. Figure 4 and Figure 5The battery pack 1 may include a battery box and a plurality of battery modules 4 disposed in the battery box. The battery box includes an upper box body 2 and a lower box body 3. The upper box body 2 can cover the lower box body 3 and form a closed space for accommodating the battery modules 4. The plurality of battery modules 4 can be arranged in the battery box in any manner.

[0163] The battery pack may be configured with a cooling system, wherein the cooling system includes the coolant.

[0164] In a fourth aspect, an embodiment of the present application provides an electrical device, comprising the battery of the third aspect of the present application.

[0165] In addition, the present application also provides an electrical device, which includes at least one of the secondary battery, battery module, or battery pack provided in the present application. The secondary battery, battery module, or battery pack can be used as a power source for the electrical device, or as an energy storage unit for the electrical device. The electrical device may include mobile devices (such as mobile phones, laptops, etc.), electric vehicles (such as pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc., but are not limited thereto.

[0166] As an electrical device, a secondary battery, a battery module or a battery pack can be selected according to its usage requirements.

[0167] Figure 6 The power consumption device is taken as an example. The power consumption device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle. In order to meet the high power and high energy density requirements of the power consumption device for the secondary battery, a battery pack or a battery module can be used.

[0168] Another example of a device may be a mobile phone, a tablet computer, a notebook computer, etc. Such a device is usually required to be thin and light, and a secondary battery may be used as a power source.

[0169] The technical solution of the present application is further described in detail below in conjunction with specific embodiments. It should be understood that the following embodiments are only used to explain the present application and are not used to limit the present application.

[0170] The parameters of the coolants of Examples 1 to 19 of the present application and Comparative Example 1 are according to the parameters in Table 1, wherein the defoaming agent is polyether-modified polydimethylsiloxane, and the coloring agent is disperse blue RRL.

[0171]

[0172] Embodiment 20

[0173] A method for preparing a coolant comprises the following steps:

[0174] Mix 40 parts of ultrapure water with 59 parts of ethylene glycol to obtain mixture 1;

[0175] One part of 2-methylpyrrole was mixed with mixture 1 to obtain a cooling liquid.

[0176] Embodiment 21

[0177] A method for preparing a coolant comprises the following steps:

[0178] Mix 40 parts of ultrapure water with 58.4 parts of ethylene glycol to obtain mixture 1;

[0179] Mixing 2-methylimidazole and 2,6-diaminopyridine in a mass ratio of 1:1 to obtain a corrosion inhibitor;

[0180] Mix 1 part of the corrosion inhibitor mixture 1 to obtain a mixture 2;

[0181] 0.3 parts of polyether-modified polydimethylsiloxane and 0.3 parts of disperse blue RRL were mixed with mixture 2 to obtain a coolant.

[0182] The coolants of Examples 1 to 19 and Comparative Example 1 were tested as follows:

[0183] Performance Testing

[0184] Specific gravity: Tested according to ASTM D1122.

[0185] Viscosity: Tested in accordance with standard GB / T 265.

[0186] Conductivity: Tested in accordance with standard TB / T 2059.5.

[0187] pH value: Tested in accordance with standard SH / T 0069.

[0188] Reserve alkalinity: Tested in accordance with standard SH / T 0091.

[0189] Corrosion inhibition efficiency of cast aluminum and brass:

[0190] The corrosion inhibition of metal in coolant was determined by three-electrode polarization curve method. Metal was used as working electrode, Pt electrode as counter electrode, saturated calomel electrode as reference electrode, and the polarization curve in the voltage range of -0.5V to 0.5V was scanned at a scanning rate of 5mV / s. Then, the slope of polarization curve of different coolant systems was obtained by Tafel fitting, and then the self-corrosion current density and corrosion rate were obtained. Based on the corrosion current density Jcorr(0) without corrosion inhibitor and the self-corrosion current density Jcorr(1) with corrosion inhibitor obtained by Tafel polarization curve fitting, the corrosion inhibition efficiency (η) of different corrosion inhibitor systems was calculated by formula (1).

[0191]

[0192] The statistical experimental results are shown in Table 2.

[0193] Table 2 Performance test results of Examples 1 to 19 and Comparative Example 1

[0194]

[0195] It can be seen from Table 2 that the unshared electron pairs of nitrogen atoms in the heterocyclic molecular structure participate in cyclic conjugation, which reduces the electron density of nitrogen atoms, enables the coordination of nitrogen atoms with metals, and forms a dense coordination adsorption layer on the outer layer of the metal, thereby improving the anti-corrosion effect of metals, especially aluminum alloy water-cooled plates, reducing metal corrosion, reducing scale formation, and improving the cooling effect of the coolant.

[0196] The mass proportion of the organic non-ionic compound containing nitrogen heterocycle in the coolant is 0.1% to 2%. Within this range, it can reduce the corrosion to the metal and reduce the effect on the viscosity of the coolant, thereby reducing the effect on the cooling effect of the coolant. At the same time, it can reduce the raw material cost of the coolant.

[0197] By adding two corrosion inhibitors, wherein the first corrosion inhibitor includes an imidazole non-ionic corrosion inhibitor and the second corrosion inhibitor includes a pyridine non-ionic corrosion inhibitor, it is possible to reduce the corrosion to the metal while reducing the generation of H in the coolant during long-term use. + When the coolant generates OH during long-term use, the free imidazole and pyridine in the coolant will combine with H+ to form imidazolium cation / pyridinium cation. - When the imidazolium cation / pyridinium cation reacts with OH - Imidazole / pyridine is formed, which plays a buffering role in adjusting the pH within the appropriate range, reduces the change of the pH value of the coolant, realizes the dynamic regulation of the pH of the coolant, and effectively inhibits the acidification of the system caused by the long-term use of the coolant. In addition, the aqueous solutions of imidazole and pyridine substances are weakly alkaline, so the initial coolant is alkaline, which further reduces the probability of hydrogen evolution corrosion of the metal.

[0198] Due to the presence of hydrophobic methyl groups, the corrosion inhibition effect of 2-methylimidazole is further enhanced, and 2-methylimidazole forms a protective surface film on the metal surface. In the protective surface film, the polar pyridine part acts as a hydrophilic polar head facing the metal surface, and the non-polar hydrophobic hydrocarbon chain floats in the coolant, which can block the coolant and the metal as much as possible, thereby inhibiting corrosion. 2-aminopyridine with two electron donor nitrogen atoms can serve as a bidentate ligand to form a chelate complex with metal atoms, which enhances the coordination between the corrosion inhibitor and the metal and enhances the compactness of the adsorption layer.

[0199] The higher the proportion of 2,6-diaminopyridine in the coolant formula, the better the corrosion inhibition effect and the higher the reserve alkalinity of the coolant. This is because the amino group is an alkaline group that can accept proton hydrogen in the coolant to form amino ions, which inhibit the acidification of the coolant. In addition, since the nitrogen atom on the amino group has a lone pair of electrons, it will promote the coordination adsorption of the substance and the metal and strengthen the tightness of the adsorption layer.

[0200] The mass ratio of the first corrosion inhibitor to the second corrosion inhibitor is (0.5-8):1; at this mass ratio, the pH value of the buffer solution is adjusted more effectively and the corrosion inhibition effect is better.

[0201] Since no corrosion inhibitor was added in Comparative Example 1, there was no adsorption layer of the corrosion inhibitor on the metal surface, and the anti-corrosion effect on the metal was very poor.

[0202] The above are only preferred embodiments of the present application, and do not limit the scope of the present application. For those skilled in the art, the present application may have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the scope of the patent protection of the present application.

Claims

1. A cooling liquid, characterized in that: Includes cooling solvents and corrosion inhibitors; Wherein, the corrosion inhibitor comprises an organic non-ionic compound containing a nitrogen heterocycle.

2. The coolant according to claim 1, characterized in that The nitrogen-containing heterocyclic organic non-ionic compound includes at least one of pyridine compounds, imidazole compounds, pyrrole compounds, pyrimidine compounds, purine compounds, triazole compounds and tetrazole compounds.

3. The cooling liquid according to claim 2, characterized in that The pyridine compound includes at least one of pyridine, 2-methylpyridine, 3-methylpyridine, p-nitropyridine, 2-aminopyridine, 2,6-diaminopyridine, 4-ethylpyridine, 4-propylpyridine, 4-pentylpyridine, 4-aminopyridine, 4-benzylpyridine and 3-benzylpyridine; and / or, The imidazole compound includes at least one of imidazole, 2-methylimidazole, 2-ethylimidazole, 2-phenylimidazole, benzimidazole, 4-phenylimidazole, 4-methylimidazole, 2,2'-biimidazole, 2,4,5-triphenylimidazole, imidazoline and 2-phenylimidazoline; and / or, The pyrrole compound includes at least one of pyrrole, 2-methylpyrrole, 2-ethylpyrrole, 2-nitropyrrole, 2-sulfonic acid pyrrole, 3-methylpyrrole, 3-heptylpyrrole and 2,5-dimethylpyrrole; and / or, The pyrimidine compound includes at least one of pyrimidine, 4-aminopyrimidine, 4-methylpyrimidine, 4,6-dimethylpyrimidine, 5-aminopyrimidine, 2,2'-bipyrimidine and 4,6-dimethoxypyrimidine; and / or, The purine compound includes at least one of purine, guanine, 7-methylguanine, isoguanine, adenine, 3-methyladenine and 8-azaguanine; and / or, The triazole compound includes at least one of 1,2,3-triazole, 1,2,4-triazole, benzotriazole, 3-nitro-1,2,3-triazole, 3-nitro-1,2,3-triazole, 3,5-dimethyl-1,2,4-triazole and 5-methyl-1-benzotriazole; and / or, The tetrazole compound includes at least one of 5-methyltetrazole, 5-benzyl-1H-tetrazole, 5-amino-1H-tetrazole, pentylenetetrazolium, tetrazole, 5-(3-pyridyl)-1H-tetrazole, 5-(4-pyridyl)-1H-tetrazole and 5-phenyl-1H-tetrazole.

4. The coolant according to any one of claims 1 to 3, characterized in that: The mass proportion of the organic non-ionic compound containing nitrogen heterocycle in the coolant is 0.1% to 2%. Optionally, the mass proportion of the organic non-ionic compound containing nitrogen heterocycle in the coolant is 0.1% to 1.5%.

5. The coolant according to any one of claims 1 to 4, characterized in that: The corrosion inhibitor comprises a first corrosion inhibitor and a second corrosion inhibitor; Wherein, the first corrosion inhibitor comprises an imidazole non-ionic corrosion inhibitor: The second corrosion inhibitor includes a pyridine non-ionic corrosion inhibitor.

6. The cooling liquid according to claim 5, characterized in that The imidazole non-ionic corrosion inhibitor includes at least one of imidazole and 2-methylimidazole; and / or, The pyridine non-ionic corrosion inhibitor includes at least one of pyridine, 2-aminopyridine, 2,6-diaminopyridine and hexahydropyridine.

7. The cooling liquid according to claim 5 or 6, characterized in that: The mass ratio of the first corrosion inhibitor to the second corrosion inhibitor is (0.5-8):1; optionally, the mass ratio of the first corrosion inhibitor to the second corrosion inhibitor is (1-4):

1.

8. The coolant according to any one of claims 1 to 7, characterized in that: The cooling solvent includes ethylene glycol and water, wherein: The purity of the ethylene glycol is >99.9%; and / or, The electrical conductivity of the ethylene glycol is less than 0.1 uS / cm (25° C.); and / or, The water is ultrapure water; and / or, The electrical conductivity of the water is less than 0.1 uS / cm (25° C.); and / or, The mass ratio of the ethylene glycol to water is (1-10):

1. Optionally, the mass ratio of the ethylene glycol to water is (1.13-5.67):

1.

9. The coolant according to any one of claims 1 to 8, characterized in that: The cooling liquid also includes an auxiliary agent.

10. The cooling liquid according to claim 9, characterized in that The auxiliary agent includes a defoamer and a colorant, wherein: The defoaming agent comprises a polyether-modified polysiloxane compound; and / or, The dyeing agent includes an azo dye compound or an anthraquinone dye compound.

11. The cooling liquid according to claim 10, characterized in that The defoaming agent comprises polyether-modified polydimethylsiloxane, the molecular weight of the polyether-modified polydimethylsiloxane is 10,000-30,000, and optionally, the molecular weight of the polyether-modified polydimethylsiloxane is 13,000-15,000.

12. The cooling liquid according to claim 10 or 11, characterized in that: In the coolant: The mass proportion of the cooling solvent is 97% to 99.7%; The mass percentage of the corrosion inhibitor is 0.1% to 2.5%; The mass proportion of the defoaming agent is 0.1% to 0.3%; The mass proportion of the dye is 0.05% to 0.3%.

13. A method for preparing a coolant according to any one of claims 1 to 12, characterized in that: The following steps are involved: Mixing the cooling solvent and the corrosion inhibitor to obtain a cooling liquid; Wherein, the corrosion inhibitor comprises an organic non-ionic compound containing a nitrogen heterocycle.

14. The method for preparing a cooling liquid according to claim 13, characterized in that: The step of "mixing the cooling solvent with the corrosion inhibitor to obtain a cooling liquid" comprises: Mix ethylene glycol with water to obtain a cooling solvent; Mixing the first corrosion inhibitor with the second corrosion inhibitor to obtain a corrosion inhibitor; Mixing the corrosion inhibitor with the cooling solvent to obtain a premixed solution; The premixed solution is mixed with the defoaming agent and the coloring agent to obtain a cooling liquid; Wherein, the first corrosion inhibitor comprises an imidazole non-ionic corrosion inhibitor: The second corrosion inhibitor includes a pyridine non-ionic corrosion inhibitor.

15. A battery, characterized in that: It comprises a battery body and a cooling system, wherein the cooling system comprises the coolant as described in any one of claims 1 to 12, or the coolant prepared by the method for preparing the coolant as described in any one of claims 13 to 14.

16. An electrical device, characterized in that: Comprising the battery of claim 15.

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