Method for rapidly judging overvoltage of silicon carbon pole piece by using temperature difference
By measuring the temperature difference before and after rolling silicon-carbon electrode sheets and comparing it with the safe temperature range, the over-pressure of silicon-carbon electrode sheets can be determined in real time. This solves the problem of crushing detection during the rolling process of silicon-carbon electrode sheets, realizes real-time monitoring and early warning functions, and improves safety and production efficiency.
Patent Information
- Application Number
- CN202511745395.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-25
- Publication Date
- 2026-02-10
AI Technical Summary
Existing technologies cannot quickly and effectively detect whether silicon-carbon electrodes are crushed during the rolling process, resulting in the exposure of SiC particles and affecting the energy density and safety of the battery cell.
By measuring the temperature difference of the silicon-carbon electrode before and after rolling, and comparing it with the safe temperature range, it is determined in real time whether the silicon-carbon electrode is over-pressured. The infrared thermometer, thermal imager and other equipment are used for precise measurement, and the alarm system is linked to prevent over-pressure.
It enables real-time monitoring of crushing during the rolling process of silicon-carbon electrode sheets, preventing electrode scrap, reducing economic losses, and improving safety.
Smart Images
Figure CN121499588A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of silicon-carbon electrode testing, specifically a method for rapidly determining overvoltage of silicon-carbon electrodes using temperature differences. Background Technology
[0002] The demand for improved energy density in lithium-ion batteries is becoming increasingly urgent. Since the pure graphite anode system can no longer meet the current energy density requirements of lithium batteries, the industry has widely adopted the use of Si-containing materials (such as bulk silicon, nano-Si, SiC) to compound with graphite to obtain silicon-graphite hybrid anodes (hereinafter referred to as silicon-carbon anodes). Since the specific capacity of Si is 4200mAh / g, which is close to 11 times that of graphite (the theoretical limit of graphite is ~372mAh), it can effectively improve the overall specific capacity of the anode, reduce the thickness of the anode, and thus improve the overall energy density of the cell.
[0003] However, due to the low compaction density of Si-containing materials, such as SiC with a compaction density of only 0.7~1.0 g / cm³, the compaction density of Si-containing materials is relatively low. 3 It is much lower than the compacted density of graphite, which is 1.6~1.9 g / cm³. 3 This process causes SiC particles to be easily crushed during the rolling of silicon-carbon negative electrode sheets, exposing the internal silicon particles to the outside. Si reacts with H2O and O2 components in the air, causing the Si material to lose its activity. As a result, the energy density of the battery cell cannot be effectively improved. Furthermore, there is currently no effective means to quickly detect and determine when SiC graphite is crushed, leaving this unsafe processing state uncontrollable.
[0004] Therefore, how to provide a method for quickly determining the overvoltage of silicon-carbon electrodes using temperature difference has become a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention
[0005] To address at least one technical problem in the background art, the present invention provides a method for rapidly determining overpressure of silicon-carbon electrode sheets using temperature difference, which can detect and determine in real time whether crushing occurs during the rolling process of silicon-carbon negative electrode.
[0006] To achieve the above objectives, the present invention provides a method for rapidly determining overvoltage of silicon-carbon electrodes using temperature difference, comprising the following steps: S1. Use temperature tester one to measure the surface temperature of the silicon-carbon negative electrode sheet before rolling and record the measurement results into the computer temperature monitoring system. S2, roll the silicon-carbon negative electrode sheet to the set compaction. After rolling, use temperature tester 2 to measure the surface stability of the silicon-carbon negative electrode sheet and enter the result into the computer temperature monitoring system to calculate the temperature difference. S3, through multiple compaction tests, obtained a safe temperature range; S4 compares the currently measured temperature difference with the set safe temperature range. If it exceeds the safe temperature range, it is determined that the silicon-carbon negative electrode is over-voltage.
[0007] Furthermore, in S2, the method for calculating the temperature difference is as follows: The temperature measured by the temperature tester is T 1. The temperature measured by the temperature tester is... T 2. Temperature difference Δ T=T 2 - T 1; The calculation method for electrode compaction is: PD = CW / (Hh); Wherein, PD stands for electrode compaction, and the unit is g / cm³. 3 CW represents the material weight per unit area of the electrode, in g / cm³. 2 H represents the total thickness of the electrode, in cm; h represents the thickness of the current collector, in cm.
[0008] Furthermore, in S3, the method for obtaining the safe temperature range through multiple compaction tests is as follows: Following the operating procedures of S1 and S2, perform different roller compaction processes PD1~PD1 ten times consecutively. 10 Ten sets of corresponding temperature difference data Δ were obtained. T 1~Δ T 10 Furthermore, SEM cross-sectional images of ten groups of silicon-carbon electrode sheets after different compaction were analyzed to determine the silicon-carbon particle breakage ratio, resulting in a table showing the correlation between compaction, temperature difference, and breakage. The safe temperature range obtained from the table was then set as follows. T a ~ T b No silicon-carbon particle breakage occurred in this range.
[0009] Furthermore, in S4, the specific method for determining overvoltage of the silicon-carbon negative electrode is as follows: The safe temperature range of the system during subsequent rolling processes. T 3 ~T 4 is set as T a ~ T b During the processing, the system will automatically test stability and calculate Δ. T， At the same time, it is compared with the set safe temperature range. If it exceeds the safe temperature range, it is determined that the silicon-carbon negative electrode is over-voltage. The alarm system controls automatic shutdown, alarm, and notifies the operator to intervene.
[0010] Furthermore, temperature tester one and temperature tester two employ one or more of infrared thermometers, thermal imagers, and thermistors to measure the surface temperature of the silicon-carbon anode sheet as accurately as possible without damaging it, with the temperature accuracy controlled within 0.1℃~1℃.
[0011] The beneficial effects of this invention are as follows: This invention provides a method for rapidly detecting the state of silicon-carbon anodes, enabling real-time monitoring of whether silicon-carbon anode sheets are crushed after rolling. Its main functions are threefold: 1. Real-time detection and determination of whether crushing occurs during the rolling process of silicon-carbon anodes; 2. Proactive early warning: upon detecting crushing of the silicon-carbon anode sheet, the system can trigger the equipment alarm function, automatically alarming and shutting down to prevent more sheets from being over-pressed and scrapped, thus reducing economic losses; 3. Safety benefits: excessive heat release can lead to dangerous situations such as spontaneous combustion of the electrode sheets; this automatic detection and determination method can provide a predictive and early warning function. Attached Figure Description
[0012] Figure 1 This is a schematic diagram of the structure of the present invention.
[0013] In the diagram: 1-Temperature tester one, 2-Temperature tester two, 3-Computer temperature monitoring system, 4-Silicon-carbon negative electrode sheet, 5-Rolling equipment, 6-Alarm system. Detailed Implementation
[0014] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0015] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this application described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.
[0016] In this application, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "vertical," "horizontal," "lateral," and "longitudinal" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing this application and its embodiments, and are not intended to limit the indicated device, element, or component to having a specific orientation, or to be constructed and operated in a specific orientation.
[0017] Furthermore, in addition to indicating location or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in some cases to indicate a certain dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.
[0018] Furthermore, the terms "installation," "setup," "equipped with," "connection," "linking," and "socketing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral structure; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium, or an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.
[0019] The method for rapidly detecting the state of silicon-carbon anode sheets of this invention determines whether the silicon-carbon anode has been crushed by detecting the temperature of the silicon-carbon anode sheet before and after rolling. Upon determining crushing, an alarm and shutdown are triggered via the linked rolling mechanism. The underlying mechanism of temperature change during the rolling of silicon-carbon anode sheets is that after the silicon-carbon material is crushed, the internal nano-silicon loses the protection of its surface coating, directly contacts the air, undergoes a chemical reaction, and releases heat. Its chemical formula is: Si+ → Si (Exothermic) Si+2 O → Si +2 ↑ (Exothermic) The exothermic chemical reaction causes the electrode temperature to rise, so temperature detection can be used to determine whether the silicon-carbon anode has been crushed.
[0020] To achieve the above objectives, such as Figure 1 As shown, this invention provides a method for rapidly determining overvoltage of silicon-carbon electrodes using temperature difference, comprising the following steps: S1, using temperature testing instrument 1, the surface temperature of the silicon-carbon negative electrode sheet 4 before rolling is measured, and the measurement result is entered into the computer temperature monitoring system 3. The measurement result is... T 1; S2, the silicon-carbon negative electrode sheet is rolled to the set compaction PD1. After rolling by the rolling equipment 5, the surface stability of the silicon-carbon negative electrode sheet 4 is measured using a temperature tester 2, and the result is entered into the computer temperature monitoring system 3. The measurement result is... T 2. The computer temperature monitoring system 3 automatically calculates the temperature difference; The method for calculating the temperature difference is as follows: The temperature measured by the temperature tester is T 1. The temperature measured by the temperature testing instrument is 2. T 2. Temperature difference Δ T= T 2 -T 1; The calculation method for electrode compaction is: PD = CW / (Hh); Wherein, PD stands for electrode compaction, and the unit is g / cm³. 3 CW represents the material weight per unit area of the electrode, in g / cm³. 2 H represents the total thickness of the electrode, in cm; h represents the thickness of the current collector, in cm.
[0021] S3, through multiple compaction tests, determined the safe temperature range using the following method: Following the operating procedures of S1 and S2, perform different roller compaction processes PD1~PD1 ten times consecutively. 10 Ten sets of corresponding temperature difference data Δ were obtained. T 1~Δ T 10 Furthermore, SEM cross-sectional images of ten groups of silicon-carbon electrode sheets after different compaction were analyzed to determine the silicon-carbon particle breakage ratio, resulting in a table showing the correlation between compaction, temperature difference, and breakage. The safe temperature range obtained from the table was then set as follows. T a ~ T b No silicon-carbon particle breakage occurred in this range.
[0022] S4 compares the currently measured temperature difference with the set safe temperature range. If it exceeds the safe temperature range, it is determined that the silicon-carbon negative electrode 4 is overvoltage. The specific method is as follows: The safe temperature range of the system during subsequent rolling processes. T 3 ~T 4 is set as T a ~ T bDuring the processing, the system will automatically test stability and calculate Δ. T， Simultaneously, the temperature is compared with the set safe temperature range. If it exceeds the safe temperature range, it is determined that the silicon-carbon negative electrode 4 is over-pressured. The alarm system 6 controls automatic shutdown and alarm, notifying the operator to intervene and prevent further material over-pressure. The crushing status of the silicon-carbon negative electrode 4 can be characterized using SEM equipment as direct evidence of silicon-carbon particle crushing; alternatively, a coin cell capacity test can be performed to verify whether the silicon-carbon particles are broken by testing the amount of active silicon.
[0023] To further optimize the technical solution, temperature tester 1 and temperature tester 2 adopt one or more of infrared thermometers, thermal imagers, and thermistors to measure the surface temperature of silicon-carbon negative electrode 4 as accurately as possible without damaging the silicon-carbon negative electrode 4, with the temperature accuracy controlled within 0.1℃~1℃.
[0024] This invention provides a method for rapidly detecting the state of silicon-carbon anodes, enabling real-time monitoring of whether silicon-carbon anode sheets are crushed after rolling. Its main functions are threefold: 1. Real-time detection and determination of whether crushing occurs during the rolling process of silicon-carbon anodes; 2. Proactive early warning: upon detecting crushing of the silicon-carbon anode sheet, the system can trigger the equipment alarm function, automatically alarming and shutting down to prevent more sheets from being over-pressed and scrapped, thus reducing economic losses; 3. Safety benefits: excessive heat release can lead to dangerous situations such as spontaneous combustion of the electrode sheets; this automatic detection and determination method can provide a predictive and early warning function.
[0025] Example
[0026] Before first use, the safety window needs to be located. The method is as follows: Perform ten different compaction tests (PD1~PD1) on a set of silicon-carbon anodes. 10 Measure its temperature and the difference Δ T 1 ~ Δ T 10 Samples were taken one by one, and the breakage of the silicon-carbon anode was observed using SEM. The following corresponding table was obtained: Table 1 Correspondence between compaction, temperature difference, and crushing conditions
[0027] Table 1 shows that the safe temperature range can be set to -1 to 4℃. No silicon carbide particle breakage occurred within this temperature range. Therefore, during subsequent rolling processes, the system's safe temperature range should be set in advance. T 3 ~T 4 Set to -1~4℃; In Example 1, the silicon-carbon anode sheet is rolled and pressed into a compacted PD. 11During the rolling process, the surface temperature of the electrode sheet before rolling is... T 1 = 23.5℃, the temperature after roller pressing is T 2 = 25.2℃; In Example 2, the silicon-carbon anode sheet is rolled and pressed into a compacted PD. 12 During the rolling process, the surface temperature of the electrode sheet before rolling is... T 1 = 23.5℃, the temperature after roller pressing is T 2 = 29.3℃; In Example 3, the silicon-carbon anode sheet is rolled and pressed into a compacted PD. 13 During the rolling process, the surface temperature of the electrode sheet before rolling is... T 1 = 23.5℃, the temperature after roller pressing is T 2 = 36.6℃; The results of the embodiments are shown in Table 1. The interface breakage state of the silicon-carbon anode sheet in the above embodiments is as follows.
[0028] Table 2. Crush Judgment Table for Silicon-Carbon Anode Sheets
[0029] Table 2 shows that when the temperature exceeds the safe range of -1 to 4℃, the silicon-carbon negative electrode sheet will be crushed, and the alarm system will control the shutdown and alarm.
[0030] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the technical scope of the present invention. Therefore, any minor modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention shall still fall within the scope of the technical solution of the present invention.
Claims
1. A method for rapidly determining overvoltage of silicon-carbon electrodes using temperature difference, characterized in that, Includes the following steps: S1. Use temperature tester one to measure the surface temperature of the silicon-carbon negative electrode sheet before rolling and record the measurement results into the computer temperature monitoring system. S2, roll the silicon-carbon negative electrode sheet to the set compaction. After rolling, use temperature tester 2 to measure the surface stability of the silicon-carbon negative electrode sheet and enter the result into the computer temperature monitoring system to calculate the temperature difference. S3, through multiple compaction tests, obtained a safe temperature range; S4 compares the currently measured temperature difference with the set safe temperature range. If it exceeds the safe temperature range, it is determined that the silicon-carbon negative electrode is over-voltage.
2. The method for rapidly determining overvoltage of silicon-carbon electrodes using temperature difference as described in claim 1, characterized in that, In S2, the method for calculating the temperature difference is as follows: The temperature measured by the temperature tester is T 1. The temperature measured by the temperature tester is... T 2. Temperature difference Δ T=T 2 -T 1; The calculation method for electrode compaction is: PD = CW / (Hh); Wherein, PD stands for electrode compaction, and the unit is g / cm³. 3 CW represents the material weight per unit area of the electrode, in g / cm³. 2 H represents the total thickness of the electrode, in cm; h represents the thickness of the current collector, in cm.
3. The method for rapidly determining overvoltage of silicon-carbon electrodes using temperature difference as described in claim 2, characterized in that, In S3, the method for obtaining the safe temperature range through multiple compaction tests is as follows: Following the operating procedures of S1 and S2, perform different roller compaction processes PD1~PD1 ten times consecutively. 10 Ten sets of corresponding temperature difference data Δ were obtained. T 1~Δ T 10 Furthermore, SEM cross-sectional images of ten groups of silicon-carbon electrode sheets after different compaction were analyzed to determine the silicon-carbon particle breakage ratio, resulting in a table showing the correlation between compaction, temperature difference, and breakage. The safe temperature range obtained from the table was then set as follows. T a ~ T b No silicon-carbon particle breakage occurred in this range.
4. The method for rapidly determining overvoltage of silicon-carbon electrodes using temperature difference as described in claim 3, characterized in that, In S4, the specific method for determining that the silicon-carbon negative electrode is overvoltage is as follows: The safe temperature range of the system during subsequent rolling processes. T 3 ~T 4 Set as T a ~ T b During the processing, the system will automatically test stability and calculate Δ. T， At the same time, it is compared with the set safe temperature range. If it exceeds the safe temperature range, it is determined that the silicon-carbon negative electrode is over-voltage. The alarm system controls automatic shutdown, alarm, and notifies the operator to intervene.
5. The method for rapidly determining overvoltage of silicon-carbon electrodes using temperature difference as described in claim 1, characterized in that, Temperature tester one and temperature tester two use one or more of infrared thermometers, thermal imagers, and thermistors to measure the surface temperature of silicon-carbon negative electrode sheets as accurately as possible without damaging the silicon-carbon negative electrode sheets, with the temperature accuracy controlled within 0.1℃~1℃.