Cylindrical battery based on microstrip reference electrode and preparation process thereof

Abstract

The invention provides a cylindrical battery based on a microstrip reference electrode and a preparation process thereof, and belongs to the technical field of lithium ion batteries, the cylindrical battery comprises a cylindrical shell, a roll core arranged in the shell and a reference electrode implanted in the roll core, the roll core is formed by laminating and winding a positive pole piece, a primary diaphragm, a negative pole piece and a secondary diaphragm; the reference electrode is of a micro-strip structure, the reference electrode is implanted into the curled side of the positive pole piece of the roll core, and the implantation depth is 1 / 2-1 / 3 of the height of the battery; the reference electrode is in an S-shaped or C-shaped bending state outside the roll core; an anti-explosion valve is arranged on an end cover of the shell, an outlet for the reference electrode to penetrate out is formed in the anti-explosion valve, the cylindrical battery three-electrode manufacturing device has the advantages of being easy to manufacture, not prone to falling off, stable in voltage, high in yield and the like, and the problems that in the cylindrical battery three-electrode manufacturing process, efficiency is low, the yield is low, and the voltage is unstable are effectively solved.

Description

Technical Field

[0001] This invention relates to the field of lithium-ion battery technology, and in particular to a cylindrical battery based on a microstrip reference electrode and its fabrication process. Background Technology

[0002] In the research and production of lithium-ion batteries, three-electrode testing technology is an important means of evaluating the electrochemical performance of the positive and negative electrodes. By introducing a reference electrode, the potential changes of the positive and negative electrodes relative to the reference electrode can be monitored separately, thereby gaining a deeper understanding of the internal electrochemical reaction process of the battery. This is of great significance for battery design optimization and performance improvement.

[0003] Currently, pouch cells are commonly used as the test carrier for three-electrode testing in the industry. Pouch cells are relatively simple in structure and easy to manufacture, facilitating the implantation and extraction of reference electrodes. However, significant differences exist between battery products of different systems and structures, meaning that three-electrode test data obtained from pouch cells cannot be accurately applied to other types of products such as cylindrical cells. While prismatic cells offer relatively high efficiency and yield in three-electrode fabrication due to their size and structural characteristics, the unique winding structure of cylindrical cells makes traditional three-electrode implantation methods unsuitable.

[0004] In subsequent manufacturing processes of cylindrical batteries, such as tab welding, sealing, electrolyte injection, and formation, production line equipment is prone to damaging the implanted reference electrode. Improper positioning or insecure fixation of the reference electrode can also lead to low production efficiency, low yield, unstable voltage, and inability to properly monitor lithium plating. These problems severely restrict the application and promotion of three-electrode technology for cylindrical batteries.

[0005] Therefore, there is an urgent need to develop a reference electrode implantation method and battery structure suitable for cylindrical batteries to solve the above-mentioned technical problems. Summary of the Invention

[0006] This invention provides a cylindrical battery based on a microstrip reference electrode and its fabrication process. By optimizing the structural design and implantation method of the reference electrode, stable implantation of the reference electrode in the cylindrical battery is achieved, effectively solving the problems of low efficiency, low yield, and unstable voltage in the fabrication of the three electrodes of the cylindrical battery.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, embodiments of the present invention provide a cylindrical battery based on a microstrip reference electrode, comprising: a cylindrical housing, a core disposed within the housing, and a reference electrode implanted inside the core. The core is formed by stacking and winding a positive electrode sheet, a primary separator, a negative electrode sheet, and a secondary separator; the reference electrode is a micro-strip structure, and the reference electrode is implanted into one side of the curled positive electrode sheet of the core, with an implantation depth of 1 / 2 to 1 / 3 of the battery height; the reference electrode is in an S-shaped or C-shaped bend outside the core. The end cap of the housing is provided with an explosion-proof valve, and the explosion-proof valve has an outlet for the reference electrode to pass through.

[0008] Optionally, half of the length region of the reference electrode is treated to remove the protective layer. The reference electrode is strip-shaped or filament-shaped. When the reference electrode is strip-shaped, its thickness is 10 to 100 μm; when the reference electrode is filament-shaped, its diameter is 10 to 100 μm.

[0009] Optionally, a diaphragm sleeve is wrapped around the middle 1 / 3 of the reference electrode. The diaphragm sleeve is coated with high-temperature adhesive and is fixed to the surface of the reference electrode by the high-temperature adhesive. The exposed end of the reference electrode passes through the outlet and is wrapped by the diaphragm sleeve. The outlet is sealed with sealing adhesive.

[0010] Optionally, the high-temperature adhesive is fixed at the top, middle, and bottom of the diaphragm sleeve, with the bottom corresponding to the overhang area of ​​the core.

[0011] Optionally, the outlet is in the shape of a straight line or a dot, and the height of the sealing adhesive matches the horizontal height of the groove of the explosion-proof valve.

[0012] Optionally, a three-stage diaphragm is provided at the position where the core is unrolled two to four times, and the reference electrode is implanted at the position where the core is unrolled two to four times through the three-stage diaphragm.

[0013] Secondly, the present invention provides a fabrication process for the above-mentioned cylindrical battery based on a microstrip reference electrode, comprising the following steps: S1. Take a microstrip reference electrode and remove the surface protective layer of its half-length region by chemical etching. S2. Wrap the middle 1 / 3 area of ​​the reference electrode with a diaphragm sleeve, and fix the diaphragm sleeve to the surface of the reference electrode with high-temperature adhesive; S3. Unroll the cylindrical core that has completed the tab flattening process two to four times to expose the positive electrode sheet, and place a three-stage diaphragm on the positive electrode sheet. S4. Place the pretreated reference electrode into the three-stage diaphragm placed in step S3, with an implantation depth of 1 / 2 to 1 / 3 of the battery height. S5. Rewind and secure the core; S6. An outlet matching the size of the reference electrode is opened on the explosion-proof valve; S7. Insert the winding core into the cylindrical housing, and at the same time pass the reference electrode out from the outlet, so that the reference electrode is in an S-shaped or C-shaped bending state inside the housing; S8. Seal the outlet using sealing adhesive.

[0014] Optionally, in step S1, the chemical corrosion is carried out using a sulfuric acid solution for 20 to 40 minutes, followed by rinsing with pure water and drying.

[0015] Optionally, in step S3, the width of the tertiary separator is half the width of the positive electrode sheet.

[0016] Optionally, in step S8, the sealing adhesive is AB adhesive, with component A and component B mixed in a 1:1 ratio, and the height of the sealing adhesive is level with the horizontal height of the explosion-proof valve groove.

[0017] The beneficial effects of this invention are as follows: By designing the reference electrode as a microstrip structure and using a diaphragm sleeve and high-temperature adhesive for fixation, the reference electrode is stably fixed inside the core, making it less prone to loosening or falling off during subsequent processing, resulting in high stability. The corrosion depth of the reference electrode is fixed at 1 / 2, and the implantation depth is controlled at 1 / 2 or 1 / 3 of the battery position, effectively increasing the conductive interface area, reducing contact resistance, and making the measured voltage more stable and accurate. The reference electrode is internally in an S-shaped or C-shaped bending state, reserving stress buffer space for subsequent processing, effectively preventing the reference electrode from being pulled off or carried out during processes such as polar current plate welding, sealing, liquid injection, and formation.

[0018] The high-temperature adhesive is fixed in the overhang area, which effectively avoids soft short circuits. At the same time, it avoids the contamination of the positive electrode by the swelling and aging of the tape in the electrolyte, reduces local lithium plating, and can effectively improve the yield.

[0019] The outlet size of the explosion-proof valve matches the reference electrode, and the height of the sealing adhesive is flush with the groove of the explosion-proof valve. This ensures a good seal and avoids the problem of mismatch between the adhesive and the injection tooling due to the protrusion of the adhesive, thus preventing leakage and injection failure.

[0020] The preparation process of this invention achieves stable and precise implantation of microstrip reference electrodes inside cylindrical battery cores through the steps of reference electrode pretreatment, positioning and implantation, and sealing and extraction. The process is simple and reliable, greatly improving the implantation success rate and operational efficiency. It is compatible with existing cylindrical battery production lines and significantly reduces production interruptions and defect rates caused by reference electrode implantation. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the overall structure of the cylindrical battery according to Embodiment 1 of the present invention; Figure 2 This is a schematic diagram of the core stacking structure according to Embodiment 1 of the present invention; Figure 3 This is a diagram showing the connection relationship between the core and the reference electrode in Embodiment 1 of the present invention; Figure 4 This is the negative electrode potential curve under the 2.5C rate stepped charging condition in Embodiment 1 of the present invention.

[0022] In the diagram: 1-shell; 2-core; 3-reference electrode; 11-explosion-proof valve; 21-positive electrode; 22-primary diaphragm; 23-negative electrode; 24-secondary diaphragm; 25-overhang region; 4-tertiary diaphragm. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0024] Table 1 shows the statistical results of the finished product yield data of each embodiment and comparative example of the present invention; Figure 1 This is a schematic diagram of the overall structure of the cylindrical battery according to Embodiment 1 of the present invention; Figure 2 This is a schematic diagram of the core stacking structure according to Embodiment 1 of the present invention; Figure 3 This is a diagram showing the connection relationship between the core and the reference electrode in Embodiment 1 of the present invention; Figure 4 This is the negative electrode potential curve under the 2.5C rate stepped charging condition in Embodiment 1 of the present invention. Figures 1 to 4 As shown in Table 1, this invention provides a cylindrical battery based on a microstrip reference electrode and its fabrication process, aiming to solve the technical problems of low efficiency, low yield, and unstable voltage in the fabrication of the three electrodes of a cylindrical battery.

[0025] Example 1 This embodiment provides a cylindrical battery based on a microstrip reference electrode, including a cylindrical housing 1, a core 2 disposed within the housing 1, and a reference electrode 3 implanted inside the core 2.

[0026] The core 2 is formed by stacking and winding a positive electrode 21, a primary separator 22, a negative electrode 23, and a secondary separator 24. The reference electrode 3 is a micro-strip structure. The reference electrode 3 is implanted into one side of the curled positive electrode 21 of the core 2, with an implantation depth of 1 / 2 to 1 / 3 of the battery height. The reference electrode 3 is in an S-shaped or C-shaped bend outside the core 2. An explosion-proof valve 11 is provided on the end cap of the housing 1, and an outlet for the reference electrode 3 to pass through is opened on the explosion-proof valve 11.

[0027] Optionally, the core 2 is formed by stacking and winding a positive electrode 21, a primary separator 22, a negative electrode 23, and a secondary separator 24. The primary separator 22 is used to separate the positive electrode 21 and the negative electrode 23 to prevent the positive electrode 21 from directly contacting the negative electrode 23 and causing a short circuit. Since the positive electrode 21, the primary separator 22, the negative electrode 23, and the secondary separator 24 need to be stacked and wound, the winding direction is towards the positive electrode 21. The secondary separator 24 can prevent the outer side of the negative electrode 23 from contacting the positive electrode 23 after winding. The reference electrode 3 is a micro-strip structure and is directly in contact with the positive electrode 21 of the core 2. The reference electrode 3 is implanted into one side of the curled positive electrode 21 of the core 2. The implantation depth is 1 / 2 to 1 / 3 of the battery height. Specifically, the implantation depth is 1 / 2 to 1 / 3 of the battery height from top to bottom. The reference electrode 3 is in an S-shaped or C-shaped bend outside the core 2. The S-shaped or C-shaped bend can reserve stress buffer space for subsequent processing. The end cap of the housing 1 is provided with an explosion-proof valve 11, and the explosion-proof valve 11 has an outlet for the reference electrode 3 to pass through.

[0028] Optionally, half of the length of the reference electrode 3 is treated to remove the protective layer. The reference electrode 3 is either strip-shaped or filament-shaped. When the reference electrode 3 is strip-shaped, its thickness is 10 to 100 μm, and the width of the strip-shaped reference electrode 3 can be cut to a value according to actual needs. When the reference electrode 3 is filament-shaped, its diameter is 10 to 100 μm. Exemplarily, in the embodiments of the present invention, the width of the strip-shaped reference electrode 3 is controlled to be 10 to 100 μm, and the thickness is controlled to be 10 to 100 μm; the diameter of the filament-shaped reference electrode 3 is controlled to be 10 to 100 μm. The purpose of both is to facilitate implantation into the core and not to cause significant interference to the internal structure of the battery. The length of the reference electrode 3 can be cut to a value according to actual needs.

[0029] Optionally, a diaphragm sleeve is wrapped around the middle third of the reference electrode 3. The diaphragm sleeve is coated with high-temperature adhesive and fixed to the surface of the reference electrode 3 by the adhesive. The exposed end of the reference electrode 3 passes through the outlet and is then wrapped by the diaphragm sleeve. The outlet is sealed with sealing adhesive. For example, in an embodiment of the present invention, the exposed end being wrapped by the diaphragm sleeve effectively prevents it from contacting the metal of the casing or end cap, thus preventing a short circuit. The outlet is sealed with sealing adhesive, ensuring no electrolyte leakage while also securing the lead wire, preventing it from being pulled out or broken due to force during electrolyte injection, formation, or other processes. Optionally, the high-temperature adhesive is fixed at the top, middle and bottom of the diaphragm sleeve, wherein the bottom corresponds to the overhang region 25 of the core 2. For example, in an embodiment of the present invention, the overhang region 25 is specifically the portion of the opposite positive electrode that extends beyond the edge of the negative electrode after winding.

[0030] Optionally, the outlet is either straight or dotted, and the height of the sealing adhesive matches the horizontal height of the explosion-proof valve groove. For example, in an embodiment of the invention, the straight opening is adapted to a strip electrode, and the dotted opening is adapted to a wire electrode, both minimizing the opening size and maximizing the maintenance of the original mechanical strength and explosion-proof function of the explosion-proof valve while ensuring smooth electrode lead-out. The sealing adhesive height is level with the explosion-proof valve groove; the sealing adhesive does not completely cover the explosion-proof valve, only ensuring a complete seal at the opening, maintaining the flatness of the battery top cover, ensuring smooth subsequent processes and the safe and stable long-term use of the battery. Optionally, a three-stage diaphragm 4 is provided at the position where the core 2 is unwound two to four times. The reference electrode 3 is implanted at the position where the core 2 is unwound two to four times through the three-stage diaphragm 4. Exemplarily, in the embodiment of the present invention, the implantation position of the reference electrode 3 avoids the loosening of the outermost electrode due to insufficient tension, and also prevents implantation difficulties or damage to the innermost layer due to excessive winding. The three-stage diaphragm 4 is used to ensure that there is no contact short circuit between the reference electrode 3 and the positive electrode plate 21, while providing uniform support.

[0031] In addition, this embodiment, based on the 40140 cylindrical battery, provides a cylindrical battery fabrication process based on a microstrip reference electrode. The specific fabrication process is as follows: 1. Select a copper strip with a length of 140 mm, a width of 3 mm, and a thickness of 20 μm as reference electrode 3. Immerse the copper strip in a beaker containing dilute sulfuric acid solution, controlling the liquid level to reach 70 mm of the copper strip, i.e., half the length of the copper strip being etched. Immerse for 30 minutes to allow the surface protective layer to be fully dissolved and removed. After etching, remove the copper strip, rinse it thoroughly with deionized pure water, and then place it in an oven at 60°C for 5 minutes until completely dry. The used sulfuric acid solution can be collected and reused.

[0032] 2. Take a diaphragm strip with a width of 50mm and wrap it around the copper strip from 60mm below the bottom to form a diaphragm sleeve. The wrapping length should be approximately 50mm, covering about 1 / 3 of the middle area of ​​the copper strip. Use high-temperature resistant tape to secure the diaphragm sleeve at the top, middle, and bottom positions, ensuring a tight fit against the copper strip surface and preventing displacement. The bottom fixing position corresponds to the Overhang area in the subsequent core winding.

[0033] 3. Take the 40140 cylindrical core that has completed the tab flattening process, and unfold it two turns starting from the outermost layer to fully expose the positive electrode 21. Place a three-stage diaphragm with a width of about 70mm (half the width of the positive electrode 21) on the exposed positive electrode 21.

[0034] 4. Place the pre-treated copper strip from step 2 into the tertiary diaphragm placed in step 3. The implantation length of the copper strip is approximately 70mm, which is half the total length of the copper strip. The implantation position is located at half the height of the battery.

[0035] 5. After the copper strip is implanted, slowly and evenly apply tension to rewind core 2 back to its original winding state. Use blue fixing tape to secure the outer layer of core 2 to prevent core 2 from loosening or unwinding.

[0036] 6. Remove the protective tape on the explosion-proof valve 11 position on the polar current plate (end cap assembly) of the housing 1. Use a utility knife or special tool to cut a 30μm wide incision on the explosion-proof valve 11, the size of which matches the width of the copper strip.

[0037] 7. Insert the prepared core 2 into the cylindrical metal housing 1, and simultaneously pass the copper strip through the straight outlet of the explosion-proof valve 11, ensuring that the first high-temperature adhesive fixing point is completely exposed outside the housing. The copper strip is in an S-shaped bend inside the end cap of the housing 1, reserving stress buffer space for subsequent processing.

[0038] 8. Before the injection process, thoroughly mix components A and B of the AB adhesive in a 1:1 mass ratio. Apply the mixed adhesive to the outlet of the explosion-proof valve, ensuring the adhesive surface is flush with the level of the valve's groove. Allow it to stand at room temperature for 30 minutes until the adhesive is completely cured.

[0039] 9. Wrap the exposed copper strip end outside the housing 1 with high-temperature tape for protection and fix it to the outer wall of the housing to prevent the copper strip from being damaged or displaced in subsequent operations.

[0040] 10. After completing the above steps, the battery can undergo subsequent processes such as electrolyte injection, formation, and capacity testing according to the conventional process flow.

[0041] Ten sample batteries were fabricated using the above process, and all were successfully produced and subjected to three-electrode performance testing, achieving a 100% pass rate. Test results show that the reference electrode 3 has a stable voltage and can accurately monitor the potential changes of both the positive and negative electrodes. Figure 4 The negative electrode potential curve shown under the 2.5C rate stepped charging condition is stable and reliable.

[0042] Example 2 This embodiment provides a cylindrical battery based on a microstrip reference electrode and its manufacturing process. The only difference from Embodiment 1 is that the reference electrode 3 is made of copper wire instead of copper strip.

[0043] Specifically, a copper wire with a diameter of 50 μm and a length of 140 mm was selected as the reference electrode 3. The copper wire has good flexibility and conductivity, and can better adapt to bending deformation inside the core 2. The remaining manufacturing process steps are the same as in Example 1, including sulfuric acid etching to remove the surface protective layer, wrapping and fixing with a diaphragm sleeve, unfolding and inserting the core 2, leading it out of the shell, and sealing it.

[0044] Ten sample batteries were manufactured using the above process, and all were successfully produced, achieving a 100% pass rate. The copper wire, used as the reference electrode 3, also demonstrated excellent voltage stability and testing reliability.

[0045] Example 3 This embodiment provides a cylindrical battery based on a microstrip reference electrode and its manufacturing process. The only difference from Embodiment 1 is that the number of turns of the core 2 is four.

[0046] Specifically, in step 3, the cylindrical core 2, which has undergone the tab flattening process, is unrolled four times from the outermost layer to implant the reference electrode 3. Unrolling it four times allows the implantation position of the reference electrode 3 to be closer to the inside of the core 2, which is beneficial for monitoring the electrochemical state of the core area of ​​the battery. The remaining manufacturing process steps are exactly the same as in Example 1.

[0047] Ten sample batteries were fabricated using the above process, and all were successfully produced, achieving a 100% pass rate. The reference electrode, implanted in four rings, remained stable, and the test data were reliable.

[0048] Example 4 This embodiment provides a cylindrical battery based on a microstrip reference electrode and its manufacturing process. The only difference from Embodiment 1 is that the reference electrode is in a C-shaped bend inside the end cap.

[0049] Specifically, during step 7, the insertion and extraction of the copper strip are adjusted to create a C-shaped bend inside the end cap. This C-shaped bend also provides a buffer for stress changes during subsequent processing, effectively preventing the copper strip from being pulled off or carried out. The remaining manufacturing process steps are exactly the same as in Example 1.

[0050] Ten sample batteries were manufactured using the above process, and all were successfully produced, with a 100% pass rate. The C-shaped bent reference electrode structure is stable and has good process adaptability.

[0051] Comparative Example To verify the necessity and rationality of the various technical features of this invention, the following comparative experiments were conducted.

[0052] Comparative Example 1 The only difference between this comparative example and Example 1 is that the corrosion depth of the reference electrode is 1 / 3 of its length, instead of 1 / 2.

[0053] Specifically, the copper strip is immersed in a sulfuric acid solution, and the liquid level is controlled so that it only reaches 1 / 3 of the copper strip's length, approximately 47 mm. The remaining process parameters and operating steps are exactly the same as in Example 1.

[0054] Ten sample batteries were manufactured using the above process, and all were successfully produced. However, the test pass rate was only 70%. The reasons were analyzed as follows: Insufficient corrosion depth reduced the effective contact area between the copper strip and the electrolyte, resulting in insufficient conductive interface area, increased contact resistance, large voltage fluctuations, and decreased measurement stability. In addition, the shallow corrosion depth made the copper strip not securely fixed inside the core, making it prone to displacement or even detachment during subsequent processing.

[0055] Comparative Example 2 The only difference between this comparative example and Example 1 is that the implantation depth of the reference electrode is 1 / 4 of the battery height, rather than 1 / 2 or 1 / 3.

[0056] Specifically, in step 4, the insertion length of the copper strip is adjusted so that it is inserted only about 35mm, located at 1 / 4 of the battery height. The remaining process parameters and operating steps are exactly the same as in Example 1.

[0057] Ten sample batteries were manufactured using the above process, and nine were successfully produced, resulting in a test pass rate of 60%. The reasons for the failure were analyzed as follows: The implantation depth was too shallow, leading to insufficient fixing length of the copper strip inside the core, making it prone to displacement or detachment during subsequent processes such as casing, welding, and electrolyte injection. Furthermore, the implantation location was off-center from the core electrochemically active region of the battery, meaning the measured potential data could not accurately reflect the overall electrochemical state of the battery.

[0058] Comparative Example 3 The only difference between this comparative example and Example 1 is that the high-temperature adhesive is fixed on the positive electrode sheet, rather than in the overhang area on the core.

[0059] Specifically, in step 2, the high-temperature adhesive is directly pasted and fixed to the surface of the positive electrode sheet, rather than being placed at the corresponding Overhang region. The remaining process parameters and operating steps are exactly the same as in Example 1.

[0060] Ten sample batteries were manufactured using the above process, and all were successfully produced, but the test pass rate was only 70%. The reason for this was that the high-temperature adhesive, in direct contact with the positive electrode sheet, would swell and age in the electrolyte environment, releasing substances that would contaminate the positive electrode active material. More seriously, the adhesive tape covering the positive electrode surface caused uneven lithium-ion intercalation in that area, resulting in excessively high local current density and lithium plating, thus affecting battery safety and cycle life.

[0061] Comparative Example 4 The only difference between this comparative example and Example 1 is that the core is only unfolded once for the reference electrode implantation operation.

[0062] Specifically, in step 3, the reference electrode is implanted after the core is unwound from the outermost layer by only one turn. Due to the characteristics of the cylindrical battery's winding structure, the winding tension of the outermost layer is inherently small, and the implantation space formed by unwound one turn is located on the outermost side of the core. The remaining process parameters and operating steps are exactly the same as in Example 1.

[0063] Ten sample batteries were manufactured using the above process, and nine were successfully produced, resulting in a test pass rate of 60%. The reason for this failure was analyzed as follows: Unwinding only one turn resulted in the reference electrode being implanted too close to the outer edge of the winding core, where the winding tension was low. The implanted copper strip was not securely fixed at this location, making it prone to loosening and displacement. Poor contact with the electrode led to increased resistance, uneven current distribution, and significant fluctuations in measurement data.

[0064] Comparative Example 5 The only difference between this comparative example and Example 1 is that the reference electrode is in a straight line inside the end cap, rather than in an S-shaped or C-shaped bend.

[0065] Specifically, in step 7, during the insertion and extraction process, the copper strip is passed through the explosion-proof valve outlet in a straight line without any bending. The remaining process parameters and operating steps are exactly the same as in Example 1.

[0066] Ten sample batteries were manufactured using the above process, but only seven successfully rolled off the production line, resulting in a 90% pass rate. The reason for this failure was the lack of stress buffer space in the straight copper strip. During subsequent processes such as electrode welding, sealing, electrolyte injection, and formation, the copper strip was easily broken or pulled out of the winding due to pressure and vibration from the equipment. Although some samples passed the tests, the overall production yield was significantly reduced.

[0067] Comparative Example 6 The only difference between this comparative example and Example 1 is that the exposed end of the reference electrode is not protected by a diaphragm sleeve.

[0068] Specifically, in step 2, the diaphragm sleeve wrapping operation is omitted, and the copper strip is directly inserted into the core in an exposed state and exits from the explosion-proof valve outlet. The remaining process parameters and operating steps are exactly the same as in Example 1.

[0069] Ten sample batteries were manufactured using the above process, and all were successfully produced. However, the test pass rate was only 50%. The reason for this was that the copper strip without a separator sleeve was in direct contact with the metal casing or end cap at the explosion-proof valve outlet, which could easily cause a short circuit. Simultaneously, the exposed copper strip underwent undesirable electrochemical reactions with the positive and negative electrode materials in the electrolyte environment, affecting the stability and accuracy of the reference electrode, resulting in a large number of samples failing the test.

[0070] Comparative Example 7 The only difference between this comparative example and Example 1 is that the explosion-proof valve outlet is fully open and the outlet size is not controlled.

[0071] Specifically, in step 6, after completely removing the protective tape from the explosion-proof valve, no opening size control is performed, and the original large-size opening is used directly. The remaining process parameters and operating steps are exactly the same as in Example 1.

[0072] Ten sample batteries were manufactured according to the above process, but all failed to complete the production line, resulting in a 0% pass rate. The analysis revealed that the excessively large outlet of the explosion-proof valve caused multiple problems. First, the large opening could not be effectively sealed, causing electrolyte leakage after injection and resulting in battery failure. Second, even when sealing with adhesive was attempted, the large opening area led to increased adhesive usage and uneven curing. Furthermore, the adhesive was incompatible with the injection fixtures during the injection process, resulting in uneven pressure distribution and sealing failure or adhesive layer rupture. In addition, the large opening allowed the internal environment to communicate with the external environment, enabling moisture and oxygen to enter the battery and severely impacting battery performance. Table 1 As can be seen from Table 1, Examples 1 to 4, which employ the technical solutions of this invention, all achieved a 100% finished product yield and a 100% test pass rate, demonstrating excellent performance. In contrast, the comparative examples, due to alterations to the key technical features of this invention, all showed varying degrees of decrease in either the yield or pass rate, fully verifying the necessity and rationality of the technical features of this invention.

[0073] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any way. Any equivalent substitutions or modifications made by those skilled in the art based on the technical solutions and concepts of the present invention should be covered within the scope of protection of the present invention.

[0074] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0075] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention.

Claims

1. A cylindrical battery based on a microstrip reference electrode, characterized in that, It includes a cylindrical housing (1), a core (2) disposed within the housing (1), and a reference electrode (3) implanted inside the core (2). The core (2) is formed by stacking and winding a positive electrode sheet (21), a primary separator (22), a negative electrode sheet (23), and a secondary separator (24); the reference electrode (3) is a micro-strip structure, and the reference electrode (3) is implanted into one side of the curled positive electrode sheet (21) of the core (2), with an implantation depth of 1 / 2 to 1 / 3 of the battery height; the reference electrode (3) is in an S-shaped or C-shaped bent state outside the core (2); The end cap of the housing (1) is provided with an explosion-proof valve (11), and the explosion-proof valve (11) has an outlet for the reference electrode (3) to pass through.

2. A cylindrical battery based on a microstrip reference electrode according to claim 1, characterized in that: The protective layer of the reference electrode (3) is removed by surface treatment in half of the length direction. The reference electrode (3) is strip-shaped or filament-shaped. When the reference electrode (3) is strip-shaped, its thickness is 10 to 100 μm; when the reference electrode (3) is filament-shaped, its diameter is 10 to 100 μm.

3. A cylindrical battery based on a microstrip reference electrode according to claim 1, characterized in that: The reference electrode (3) is wrapped with a diaphragm sleeve at the middle 1 / 3 position. The diaphragm sleeve is coated with high-temperature adhesive and is fixed to the surface of the reference electrode (3) by the high-temperature adhesive. The exposed end of the reference electrode (3) is wrapped by the diaphragm sleeve after passing through the outlet, and the outlet is sealed with sealing adhesive.

4. A cylindrical battery based on a microstrip reference electrode according to claim 3, characterized in that: The high-temperature adhesive is fixed at the top, middle and bottom of the diaphragm sleeve, with the bottom corresponding to the Overhang area (25) of the core (2).

5. A cylindrical battery based on a microstrip reference electrode according to claim 1, characterized in that: The outlet is either in the shape of a line or a dot, and the height of the sealing adhesive matches the horizontal height of the groove in the explosion-proof valve.

6. A cylindrical battery based on a microstrip reference electrode according to claim 1, characterized in that: A three-stage diaphragm (4) is provided at the position where the core (2) is unfolded two to four times, and the reference electrode (3) is implanted at the position where the core (2) is unfolded two to four times through the three-stage diaphragm (4).

7. A cylindrical battery fabrication process based on a microstrip reference electrode according to claim 1, characterized in that, Includes the following steps: S1. Take the microstrip reference electrode (3) and remove the surface protective layer of its 1 / 2 region along its length by chemical etching. S2. Wrap the middle 1 / 3 area of ​​the reference electrode with a diaphragm sleeve, and fix the diaphragm sleeve to the surface of the reference electrode with high-temperature adhesive; S3. Unfold the cylindrical core that has completed the tab flattening process two to four times to expose the positive electrode sheet, and place a three-stage diaphragm (4) on the positive electrode sheet. S4. Place the pretreated reference electrode (3) into the three-stage diaphragm (4) placed in step S3, with an implantation depth of 1 / 2 to 1 / 3 of the battery height. S5. Rewind and secure the core (2); S6. An outlet matching the size of the reference electrode (3) is opened on the explosion-proof valve (11); S7. The core (2) is inserted into the cylindrical shell (1), and the reference electrode (3) is passed out from the outlet, so that the reference electrode (3) is in an S-shaped or C-shaped bent state inside the shell. S8. Seal the outlet using sealing adhesive.

8. The cylindrical cell fabrication process based on a microstrip reference electrode according to claim 7, characterized in that: In step S1, the chemical corrosion is carried out using sulfuric acid solution for 20 to 40 minutes. After corrosion, the solution is rinsed with pure water and dried.

9. The cylindrical cell fabrication process based on a microstrip reference electrode according to claim 7, characterized in that: In step S3, the width of the tertiary diaphragm (4) is half the width of the positive electrode sheet.

10. The cylindrical cell fabrication process based on a microstrip reference electrode according to claim 7, characterized in that: In step S8, the sealing adhesive is AB adhesive, with component A and component B mixed in a 1:1 ratio, and the height of the sealing adhesive is level with the horizontal height of the explosion-proof valve groove.

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