Preparation method of overheating self-protection battery temperature-sensitive binder

Abstract

The invention relates to an effective technology for regulating and controlling overheating of a battery to cut off the charging and discharging process of the battery and spontaneously recovering the performance of the battery at room temperature by using a temperature-sensitive binder. Wherein a temperature-sensitive electrode is prepared from a temperature-sensitive binder, the battery is assembled with the temperature-sensitive electrode, and the charge-discharge process in the battery is spontaneously inhibited at a set temperature. Through the method, the heat release of the lithium ion battery at the initial stage of overheating is reduced, the thermal runaway process of the battery is delayed, and a technology is provided for thermal safety management of the battery. The temperature-sensitive response of the binder adopted by the method comes from the temperature-sensitive dynamic self-assembly of a specific polymer, so that the method has the characteristic of reversible overheating regulation and control. In addition, the binder in the method is suitable for commercial electrolyte and commercial electrode, and is suitable for large-scale production of batteries.

Description

Technical Field

[0001] This invention belongs to the field of new energy technology, and specifically relates to a battery thermal runaway prevention technology, which can be applied to various energy devices such as lithium-ion batteries, sodium-ion batteries, and zinc-ion batteries. Background Technology

[0002] Battery thermal safety issues hinder the large-scale application of high-performance power supplies and energy storage devices. While the characteristic temperatures of thermal runaway vary among different types of batteries, the heat sources during the runaway phase are essentially similar, involving internal side reactions, electrochemical reactions, and heat release from membrane melting. In the early stages of battery thermal runaway, all involve the thermal decomposition of the SEI film, belonging to the heat accumulation stage. Taking measures in the early stages of battery thermal runaway is crucial for delaying or preventing the chain reaction of thermal runaway. Currently, commercially available battery thermal management systems largely rely on external sensor monitoring and heat exchange system management, while technologies for regulating battery thermals and preventing overheating reactions within the battery are still in their infancy. Summary of the Invention

[0003] To suppress chemical reaction rates and heat release during overheating within batteries, this invention proposes a preparation technique for temperature-sensitive binders and temperature-sensitive electrodes, which can effectively reduce the specific capacitance during overheating charge and discharge. By utilizing the viscoelastic and microstructural property changes of the temperature-sensitive polymer system, the microstructure of the electrode material and its wettability with commercial electrolytes can be controlled in multiple dimensions, providing key materials and technologies for monitoring overheating temperatures and controlling overheating reactions within batteries. This technology is low-cost, simple in process, widely applicable, and environmentally friendly.

[0004] The method for preparing a temperature-sensitive battery by developing a temperature-sensitive electrode using a temperature-sensitive binder and coupling it with a conventional electrolyte and a conventional electrode, as described in this invention, includes the following process steps:

[0005] (1) Mix the thermosensitive polymer with the corresponding organic solvent and stir to obtain a thermosensitive adhesive;

[0006] (2) The temperature-sensitive adhesive described in (1) is mixed with active material, conductive material and conventional adhesive in proportion, and then pretreated.

[0007] (3) The electrode material described in (2) is thoroughly stirred and mixed at room temperature to obtain an electrode slurry, which is then coated and dried on a current collector to obtain the corresponding temperature-sensitive electrode;

[0008] (4) Assemble the electrode described in (3) with a conventional electrolyte and a conventional electrode to form a temperature-sensitive battery containing a temperature-sensitive electrode.

[0009] The polymers used in temperature-sensitive adhesives are poly(styrene acrylate) series polymers, including but not limited to poly(phenyl methacrylate), poly(phenylethyl acrylate), and poly(phenylpropyl acrylate).

[0010] The organic solvents used in temperature-sensitive adhesives are ionic liquid solvents, including but not limited to one or more combinations of ionic liquids such as alkylimidazolium, ethers, and pyridinium.

[0011] A temperature-sensitive electrode is prepared by coupling an active material, a conductive material, and a conventional binder using a temperature-sensitive adhesive. The temperature-sensitive adhesive accounts for 1-30% of the electrode mass, and the thermal runaway temperature ranges from 50-180℃. The active material used includes, but is not limited to, lithium iron phosphate and nickel-cobalt-manganese ternary materials. The conductive material used includes, but is not limited to, acetylene black and Ketjen black. The conventional binder used includes, but is not limited to, polyvinylidene fluoride type binder and carboxymethyl cellulose type binder. The current collector used includes, but is not limited to, aluminum foil, copper foil, and stainless steel foil.

[0012] Thermosensitive adhesives are used to develop thermosensitive electrodes, which include, but are not limited to, thermosensitive lithium iron phosphate cathodes, thermosensitive ternary material cathodes, thermosensitive carbon anodes, and thermosensitive silicon anodes.

[0013] A temperature-sensitive battery is obtained by coupling a temperature-sensitive electrode with a conventional electrolyte and a conventional electrode. The salts used in the conventional electrolyte include, but are not limited to: lithium trifluoromethanesulfonate, lithium tetrafluoroborate, lithium hexafluorophosphate, lithium bis(trifluoromethanesulfonyl)imide, zinc sulfate, zinc chloride, zinc trifluoromethanesulfonate, zinc tetrafluoroborate, zinc hexafluorophosphate, zinc bis(trifluoromethanesulfonyl)imide, etc. The solvents used in the conventional electrolyte include, but are not limited to: propylene carbonate, ethylene carbonate, water, etc. The conventional electrodes include, but are not limited to: lithium iron phosphate cathode, ternary material cathode, carbon anode, silicon anode, etc.

[0014] Thermosensitive batteries include, but are not limited to, lithium-ion batteries, lithium metal batteries, metal-air batteries, and zinc-ion batteries.

[0015] Compared with existing technologies, this invention combines a temperature-sensitive polymer with the initial heat accumulation stage of battery thermal runaway. It utilizes the temperature-sensitive response of the binder to viscoelastic and adhesive changes to suppress the accelerated reaction rate and heat release within the battery during overheating. The method employed involves a spontaneous thermal management and control process within the battery, effectively delaying the temperature rise and slowing down or preventing the chain reaction of battery thermal runaway. This invention has the following advantages and outstanding effects: adjustable thermal management temperature and reversible thermal response behavior. The temperature-sensitive electrode proposed in this invention is prepared by mixing a temperature-sensitive binder, active material, and conductive material. Matched with commercial electrolytes and electrodes, it achieves high-efficiency normal battery operation and a temperature response characteristic that spontaneously interrupts overheating, exhibiting reversible overheat self-protection features. This realizes the preparation and technological application of temperature-responsive battery electrodes. Therefore, the temperature-sensitive battery prepared with this electrode possesses high performance and thermal safety characteristics. Attached Figure Description

[0016] Figure 1 Process flow diagram for developing temperature-sensitive batteries using temperature-sensitive adhesives.

[0017] Figure 2 Example 1: Molecular structure of a temperature-sensitive adhesive.

[0018] Figure 3 Macroscopic and microscopic SEM images of the temperature-sensitive electrode generated in Example 1.

[0019] Figure 4 Swelling resistance of the temperature-sensitive electrode produced in Example 1 in commercial electrolyte.

[0020] Figure 5 The charge-discharge specific capacity curve of the temperature-sensitive battery generated in Example 1. Detailed Implementation

[0021] The present invention will be further described below with reference to the embodiments and accompanying drawings. The content described is only a basic description under the concept of the present invention, but the present invention is not limited to the following examples. Any equivalent transformations made based on the technical solutions of the present invention shall fall within the protection scope of the present invention.

[0022] Example 1

[0023] A lithium iron phosphate (LFP) thermosensitive electrode was prepared using an ionic liquid solution containing 5 wt% thermosensitive polymer PBnMA as a binder. The mass ratio of binder:lithium iron phosphate:supercarbon was 3:6:1, and the electrode slurry was prepared by dissolving it in NMP organic solvent. The slurry was stirred at room temperature for 1 hour, coated onto aluminum foil, and vacuum-sealed at 40°C for 12 hours to obtain the thermosensitive electrode. The molecular structure of the thermosensitive polymer PBnMA is as follows: Figure 1 As shown, the molecular weight is 12,000.

[0024] The temperature-sensitive electrode it prepared, such as Figure 2As shown, the electrode surface is uniform and does not detach under bending conditions, indicating good adhesion. The microstructure is similar to that of electrical electrodes prepared with commercial adhesives, with interconnected and uniform micropores.

[0025] The temperature-sensitive electrode produced in Case 1 was immersed in commercial electrolyte for one week without any volume change or material detachment, maintaining its good shape. Figure 3 As shown, the temperature-sensitive electrode exhibits good swelling resistance in commercial electrolytes, which is beneficial for ensuring the long-term stable use of the battery's electrochemical properties.

[0026] The charge-discharge curves of the lithium metal battery assembled in Case 1 at different temperatures are as follows: Figure 4 As shown, the specific capacitance decreases in the reverse direction at high temperatures, indicating that the electrochemical reaction process inside the battery is effectively suppressed, and the heat generation of the battery can be effectively reduced at this temperature.

Claims

1. A method for spontaneously regulating the temperature response of chemical reactions within a battery by using a temperature-sensitive binder. This method utilizes the temperature-sensitive physicochemical properties of the binder to regulate the battery's specific capacity and heat release over a wide temperature range, thereby achieving internal thermal management regulation during the initial stages of thermal runaway heat accumulation and delaying the thermal runaway reaction process. Its characteristics are as follows: The process steps for preparing the temperature-sensitive electrode using the temperature-sensitive binder are as follows: (1) Mix the thermosensitive polymer with the corresponding organic solvent and stir to obtain a thermosensitive adhesive; (2) The temperature-sensitive adhesive described in (1) is mixed with active material, conductive material and conventional adhesive in proportion, and then pretreated. (3) The electrode material described in (2) is thoroughly stirred and mixed at room temperature to obtain an electrode slurry, which is then coated and dried on a current collector to obtain the corresponding temperature-sensitive electrode; (4) Assemble the electrode described in (3) with a conventional electrolyte and a conventional electrode to form a temperature-sensitive battery containing a temperature-sensitive electrode.

2. As described in claim 1, characterized in that: The polymers used in temperature-sensitive adhesives are poly(styrene acrylate) series polymers, including but not limited to poly(phenyl methacrylate), poly(phenylethyl acrylate), and poly(phenylpropyl acrylate).

3. As described in claim 1, characterized in that: The organic solvents used in temperature-sensitive adhesives are ionic liquid solvents, including but not limited to one or more combinations of ionic liquids such as alkylimidazolium, ethers, and pyridinium.

4. As described in claim 1, characterized in that: A temperature-sensitive electrode is prepared by coupling an active material, a conductive material, and a conventional binder using a temperature-sensitive adhesive. The temperature-sensitive adhesive accounts for 1-30% of the electrode mass, and the thermal runaway temperature ranges from 50-180℃. The active material used includes, but is not limited to, lithium iron phosphate and nickel-cobalt-manganese ternary materials. The conductive material used includes, but is not limited to, acetylene black and Ketjen black. The conventional binder used includes, but is not limited to, polyvinylidene fluoride type binder and carboxymethyl cellulose type binder. The current collector used includes, but is not limited to, aluminum foil, copper foil, and stainless steel foil.

5. As described in claim 1, characterized in that: Thermosensitive adhesives are used to develop thermosensitive electrodes, which include, but are not limited to, thermosensitive lithium iron phosphate cathodes, thermosensitive ternary material cathodes, thermosensitive carbon anodes, and thermosensitive silicon anodes.

6. As described in claim 1, characterized in that: A temperature-sensitive battery is obtained by coupling a temperature-sensitive electrode with a conventional electrolyte and a conventional electrode. The salts used in the conventional electrolyte include, but are not limited to: lithium trifluoromethanesulfonate, lithium tetrafluoroborate, lithium hexafluorophosphate, lithium bis(trifluoromethanesulfonyl)imide, zinc sulfate, zinc chloride, zinc trifluoromethanesulfonate, zinc tetrafluoroborate, zinc hexafluorophosphate, zinc bis(trifluoromethanesulfonyl)imide, etc. The solvents used in the conventional electrolyte include, but are not limited to: propylene carbonate, ethylene carbonate, water, etc. The conventional electrodes include, but are not limited to: lithium iron phosphate cathode, ternary material cathode, carbon anode, silicon anode, etc.

7. As described in claim 1, characterized in that: Thermosensitive batteries include, but are not limited to, lithium-ion batteries, lithium metal batteries, metal-air batteries, and zinc-ion batteries.

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