Lithium battery material sintering furnace temperature measurement system

Abstract

The utility model provides a lithium battery material sintering furnace temperature measuring system which is composed of a high-temperature-resistant furnace temperature recorder, a water heat insulation box and a high-temperature-resistant thermocouple, and the water heat insulation box is provided with a titanium alloy shell, a nanometer composite heat insulation material and a cooling water tank. The water-containing heat insulation box is light in weight, high in strength and not prone to deformation at high temperature, metal elements such as copper and iron which pollute materials in the sagger are not contained, and long-time high-temperature temperature measurement experiments in an extremely limited heat preservation and heat insulation environment are guaranteed.

Description

Technical Field

[0001] This utility model relates to the field of lithium battery manufacturing technology, specifically to a temperature measurement system for a lithium battery material sintering furnace. Background Technology

[0002] In the production of lithium-ion battery cathode and anode materials, the sintering process requires heating and holding the materials at specific temperatures to ensure they achieve the performance specified by the process. Whether the sintering furnace can reach the designated temperature and maintain that temperature during heating and holding is the most basic and critical performance indicator to ensure the product meets requirements. Therefore, real-time temperature measurement inside the furnace is necessary to ensure the sintering furnace temperature control system can accurately control the heating process.

[0003] The existing drag-couple testing method, which involves leading the thermocouple from inside the furnace to the outside and then connecting it to the temperature recording device, has limited application. The current structure and process requirements of sintering furnaces used by lithium battery material manufacturers result in low furnace heights and furnace doors that hinder conventional drag-couple testing. Furthermore, the limited load-bearing capacity of the furnace's moving mechanisms prevents the use of excessively heavy water-insulated boxes. Additionally, strict requirements exist regarding the content of iron, copper, and other metal elements within the furnace, making conventional stainless steel water-insulated boxes unsuitable for black box testing. The requirements for black box testing in lithium battery material sintering furnaces include: small size, light weight, long furnace time, high temperature, and no iron or copper content. This has led to the current lack of temperature measurement systems for lithium battery material sintering furnaces that meet these requirements. Utility Model Content

[0004] The purpose of this invention is to provide a temperature measurement system for a lithium battery material sintering furnace, which ensures long-term high-temperature measurement experiments under extremely limited thermal insulation conditions.

[0005] The lithium battery material sintering furnace temperature measurement system of this utility model consists of a high-temperature resistant furnace temperature recorder, a water-insulated box, and a high-temperature resistant thermocouple. The water-tight high-temperature resistant furnace temperature recorder is placed in the water-insulated box, and the high-temperature resistant thermocouple enters the furnace along with the material being measured for temperature measurement.

[0006] The water-insulated box is made of titanium alloy shell;

[0007] The water-insulated box is filled with nano-composite insulation material inside the titanium alloy shell.

[0008] The water tank in the middle of the water-insulated box is equipped with cooling water, and a watertight high-temperature furnace temperature recorder is submerged in the water.

[0009] Preferably, the titanium alloy shell is a TC4 titanium alloy shell, which does not contain iron or copper.

[0010] Preferably, the filling thickness of the nanocomposite thermal insulation material is 50-65 mm.

[0011] Preferably, the nanocomposite thermal insulation material is a nanoporous thermal insulation material.

[0012] Preferably, after the water-insulated box is filled with nanocomposite material, it also has a fully welded water tank filled with cooling water.

[0013] Preferably, the dimensions of the water-insulated box are: occupying the projected area of ​​one sagger, that is, the height is equal to the height of two to three saggers, and the bottom area is the same as the dimensions of the sagger.

[0014] Preferably, the dimensions of the water-insulated box are: it occupies the bottom area of ​​two saggers in the horizontal direction, that is, the height is the same as that of one sagger.

[0015] Preferably, the water-insulated box has dimensions of 340*340*340 mm, which is suitable for sintering furnaces with high furnace chambers, i.e., sintering furnaces with double-layer sagger feeding and large ceramic roller load-bearing capacity; or the water-insulated box has dimensions of 680*340*180 mm, which is suitable for sintering furnaces with low furnace chambers, i.e., sintering furnaces with single-layer sagger feeding.

[0016] Preferably, the watertight high-temperature furnace temperature recorder comes with a built-in high-temperature watertight box.

[0017] Preferably, the high-temperature resistant thermocouple is an armored thermocouple, which is required to meet the national standard Class I accuracy and has a diameter of less than 2mm.

[0018] This utility model has the following positive effects:

[0019] The present invention discloses a temperature measurement system for a lithium battery material sintering furnace, which has a water-insulated box that is lightweight, high-strength, not easily deformed at high temperatures, and does not contain copper, iron, or other metallic elements that could contaminate the materials inside the sagger.

[0020] 1. Lightweight titanium alloy ensures strength while reducing the total weight for the same volume, meeting the weight requirements of the ceramic rollers that drive the saggers forward in the sintering furnace.

[0021] 2. Select nanocomposite insulation materials with excellent thermal insulation performance to fill the water insulation box, ensuring thermal insulation against high temperatures for a long time in a small volume.

[0022] 3. Together with the cooling water in the central water tank, the water-insulated box can effectively provide thermal insulation protection for the high-temperature furnace temperature recorder placed inside.

[0023] The lithium battery material sintering furnace temperature measurement system described in this utility model can be used for testing the temperature uniformity of sintering furnaces below 850℃. Attached Figure Description

[0024] Figure 1 This is a structural diagram of the temperature measurement system for the lithium battery material sintering furnace described in this utility model.

[0025] Components shown in the attached diagram:

[0026] 1-Water-insulated box 2-Watertight high-temperature furnace temperature recorder 3-Sheathed thermocouple 4-Saving crucible 5-Insulation layer 6-Cooling water Detailed Implementation

[0027] The following will be combined with the appendix Figure 1 The preferred embodiments of this utility model will be described in detail below.

[0028] Unlike drag-couple testing, where the recorder can be placed in a normal-temperature environment outside the kiln, black box testing refers to a testing method where the temperature measuring equipment—specifically, a high-temperature furnace temperature recorder and thermocouple cold junctions—is wrapped with multiple layers of insulation and cooling measures and placed inside a high-temperature furnace along with the product under test. The equipment is heated in different heating zones within the furnace while simultaneously collecting and recording temperature data. This testing method is similar to the black box on an aircraft, where the data recording device is protected by multiple layers to ensure it can withstand extreme environmental impacts and function normally, providing necessary data information. Therefore, this type of testing is also called black box testing.

[0029] In the lithium battery industry, lithium ions and their compounds readily react with metals such as iron and copper, resulting in a decrease in lithium ion concentration and an increase in impurity concentration in the product after heat treatment and sintering. Therefore, the lithium battery industry requires that the outer shell of the water-insulated furnace cannot be made of the same material as other heat treatment industries. While ceramic shells do not contain iron or copper, ceramic is brittle and not durable. Therefore, the lithium electrode material sintering furnace temperature measurement system described in this patent is currently the only solution for the lithium battery industry. This patent can also be applied to other fields, as long as the test temperature does not exceed 860℃ and the furnace time does not exceed 16 hours. However, other fields do not have specific requirements regarding the material of the water-insulated furnace for their heat treatment and heating processes.

[0030] The high-temperature furnace black box method involves placing the furnace temperature recorder in a high-temperature, water-insulated box. The recorder is then inserted into the furnace along with the material being tested via a thermocouple. The thermocouple, with one end connected to the furnace temperature recorder and the other end extending from the water-insulated box to the material being tested, collects and records the temperature data inside the furnace. This method is widely known in the temperature measurement industry as the black box test because it is similar to the black box used in airplanes to record cockpit voice communication and flight data.

[0031] The high-temperature resistant furnace black box consists of a high-temperature furnace temperature recorder, a water-insulated box, and high-temperature thermocouples. Its main working principle is to simultaneously place the instrument and the material crucible into the sintering furnace for heating, recording the material and furnace gas temperatures in real time. After exiting the furnace, the test data is analyzed using specialized software to understand the temperature changes throughout the heating process and the temperature uniformity differences within the furnace. This provides scientific data for the commissioning and acceptance of the sintering furnace, the establishment and verification of mathematical models, and the digitization of heating process data.

[0032] The armored thermocouple 3 is the temperature sensor of the temperature measurement system, and the sagger 4 is the container for holding lithium battery materials inside the sintering furnace. The insulation layer 5 is a nanocomposite insulation material layer.

[0033] Example 1:

[0034] The novel temperature measurement system for lithium battery positive and negative electrode material sintering furnace described in this utility model consists of a water-insulated box 1, a watertight high-temperature furnace temperature recorder 2, and a sheathed thermocouple 3.

[0035] The watertight high-temperature furnace temperature recorder 2 comes with a high-temperature watertight box, and its temperature measurement accuracy meets ≤±0.4℃ or 0.4t, with a maximum operating temperature of 85℃; the armored thermocouple 3 is required to meet the national standard Class I accuracy and have a diameter of less than 2mm to ensure that the stainless steel content entering the furnace is minimized (for the production of positive and negative electrode materials for lithium batteries, iron and copper elements are harmful substances, and contact with such elements should be minimized during the sintering process).

[0036] The dimensions of the water-insulated box 1 are consistent with those of the saggers used to hold lithium battery materials in the sintering furnace. The external dimensions match the two sizes of ceramic saggers currently used by mainstream lithium battery material manufacturers: 340*340*340mm (length, width, height) for a single double-layer sagger, or 680*340*180mm (length, width, height) for two single-layer saggers, to accommodate higher temperatures and longer furnace time.

[0037] During use, simply replacing one or two sets of saggers with the water-insulated box 1 allows for testing within the furnace. The water-insulated box 1 uses a TC4 titanium alloy shell, ensuring heat resistance and high strength while being nearly half the weight of a stainless steel shell of the same volume. This meets the load-bearing requirements of the moving mechanisms within the sintering furnace. The TC4 titanium alloy composition is: titanium 86%–88%, aluminum 6%–8%, vanadium 4%–6%, iron ≤0.30%, carbon ≤0.10%, nitrogen ≤0.05%, hydrogen ≤0.015%, and oxygen ≤0.20%. These elemental proportions meet the requirements for harmful impurities in the lithium battery raw material sintering process. The high strength, high toughness, low density, excellent corrosion resistance, and good machinability and weldability of the TC4 titanium alloy meet the requirements for processing and use.

[0038] The insulation layer in the middle of the water-insulated box is filled with a nanocomposite insulation material with better thermal insulation performance. The nanocomposite material is Unico nanoporous insulation material, composed of silicon dioxide and silicon carbide, with a thermal conductivity of 0.030 W / m K at 800℃ / 1472°F, ensuring high-temperature isolation within the limited insulation layer thickness. As the furnace time progresses, the heat seeping into the water-insulated box first heats the cooling water in the innermost water tank, thus protecting the furnace temperature recorder and providing it with a suitable operating environment temperature of <100℃. Once the internal water tank is full, it continuously maintains the temperature below 100℃ for the high-temperature resistant furnace temperature recorder, sealed within a watertight kit, until the cooling water evaporates completely. Afterwards, the furnace temperature recorder's own insulation continues to insulate the recorder's mainboard and built-in battery, ensuring that the furnace temperature recorder can completely collect the temperature of each measuring point in the sagger inside the furnace.

[0039] The system has undergone routine testing, including furnace temperature uniformity tests with the black box at 820℃ for 18 hours and 21 hours, both of which were successfully completed. A similar application was also performed in another project, with the set temperature at 850℃ and a furnace stay of up to 23 hours. To date, all tests conducted by strictly adhering to the operating procedures, ensuring thorough cooling of the water-insulated box before furnace entry, and sealing the opening tightly after filling with cooling water, have consistently guaranteed black box testing at temperatures below 850℃ for up to 24 hours.

[0040] This utility model has the following positive effects:

[0041] Water-insulated boxes are lightweight, high-strength, and not easily deformed at high temperatures. They also do not contain copper, iron, or other metallic elements that could contaminate the materials inside the sagger. Furthermore, they exhibit good oxidation resistance in certain oxygen-rich environments (furnace atmosphere with 95% oxygen content and temperature close to 1000℃).

[0042] The lithium electrode material sintering furnace temperature measurement system described in this utility model can be readily applied to the temperature uniformity testing of sintering furnaces below 850℃.

[0043] 1. Lightweight titanium alloy ensures strength while reducing the total weight for the same volume, meeting the weight requirements of the ceramic rollers that drive the saggers forward in the sintering furnace.

[0044] 2. Select nanocomposite insulation materials with excellent thermal insulation performance to fill the water insulation box, ensuring thermal insulation against high temperatures for a long time in a small volume.

[0045] 3. Together with the cooling water in the central water tank, the water-insulated box can effectively provide thermal insulation protection for the high-temperature furnace temperature recorder placed inside.

Claims

1. A temperature measurement system for a lithium battery material sintering furnace, characterized in that, It consists of a high-temperature furnace temperature recorder, a water-insulated box, and high-temperature thermocouples. The watertight high-temperature furnace temperature recorder is placed inside the water-insulated box, and the high-temperature thermocouples are inserted into the furnace along with the material being measured to measure the temperature. The water-insulated box is made of titanium alloy shell; The water-insulated box is filled with nano-composite insulation material inside the titanium alloy shell. The water tank in the middle of the water-insulated box is equipped with cooling water, and a watertight high-temperature furnace temperature recorder is submerged in the water.

2. The temperature measurement system for a lithium battery material sintering furnace as described in claim 1, characterized in that, The titanium alloy shell is a TC4 titanium alloy shell, which does not contain iron or copper.

3. The temperature measurement system for a lithium battery material sintering furnace as described in claim 1, characterized in that, The filling thickness of the nanocomposite thermal insulation material is 50-65 mm.

4. The temperature measurement system for a lithium battery material sintering furnace as described in claim 1, characterized in that, The nanocomposite thermal insulation material is a nanoporous thermal insulation material.

5. The temperature measurement system for a lithium battery material sintering furnace as described in claim 1, characterized in that, After the water-insulated box is filled with nanocomposite material, it also has a fully welded water tank filled with cooling water.

6. The temperature measurement system for a lithium battery material sintering furnace as described in claim 1, characterized in that, The dimensions of the water-insulated box are: it occupies the projected area of ​​one sagger, that is, the height is equal to the height of two to three saggers, and the bottom area is the same as the size of the sagger.

7. The temperature measurement system for a lithium battery material sintering furnace as described in claim 1, characterized in that, The dimensions of the water-insulated box are: it occupies the bottom area of ​​two saggers horizontally, and its height is the same as that of one sagger.

8. The temperature measurement system for a lithium battery material sintering furnace as described in claim 1, characterized in that, The water-insulated box has dimensions of 340*340*340 mm and is suitable for sintering furnaces with higher furnace chambers, i.e., those using double-layer sagger feeding and with large ceramic roller load-bearing capacity; or the water-insulated box has dimensions of 680*340*180 mm and is suitable for sintering furnaces with lower furnace chambers, i.e., those using single-layer sagger feeding.

9. The temperature measurement system for a lithium battery material sintering furnace as described in claim 1, characterized in that, The watertight high-temperature furnace temperature recorder comes with a built-in high-temperature watertight box.

10. The temperature measurement system for a lithium battery material sintering furnace as described in claim 1, characterized in that, The high-temperature resistant thermocouple is an armored thermocouple, which is required to meet the national standard Class I accuracy and has a diameter of less than 2mm.

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