Needle eye ring current collector, positive plate with high liquid absorption rate and button cell

Abstract

The utility model relates to the technical field of button cells, and particularly discloses a needle eye ring current collector, a positive plate with high liquid absorption rate and a button cell. The needle eye ring current collector comprises a substrate and a ring extending upwards on the periphery of the substrate, a liquid suction hole and a plurality of needle eye holes annularly formed in the periphery of the liquid suction hole are formed in the substrate, and the needle eye holes protrude towards one side of the extending direction of the ring. The positive plate comprises a needle eye ring current collector, a substrate and a ring of the needle eye ring current collector define a containing cavity, positive powder and electrolyte are contained in the containing cavity, at least part of the positive powder is exposed in the liquid suction holes, and the needle eye hole protrusions penetrate into the positive powder. According to the needle eye ring current collector structure disclosed by the utility model, the liquid absorption rate of the positive electrode is rapidly improved while the conductivity is ensured, so that the internal resistance cannot be rapidly increased due to insufficient electrofluid in the discharging process of the battery, and the problems of short discharging time and low capacity release amount of the traditional button battery under 10mA large-current pulse are solved.

Description

Technical Field

[0001] This utility model relates to the technical field of button batteries, and specifically discloses a pinhole ring current collector, a positive electrode with high liquid absorption rate, and a button battery. Background Technology

[0002] Lithium-manganese batteries have a rated voltage of 3.0 volts, approximately twice that of dry cell batteries. They offer stable discharge voltage, good storage performance, excellent high-rate discharge performance, good rapid pulse discharge capabilities, and a wide operating temperature range. Furthermore, they are safe and environmentally friendly. Therefore, they are widely used in digital cameras, portable computers, handheld computers, various smart meters (water meters, electricity meters, gas meters), alarm systems, emergency lights, medical equipment, remote control devices, and toys.

[0003] However, the positive electrode current collector of current traditional lithium manganese primary batteries is a stainless steel mesh or a bowl-shaped current collector, as follows: Figure 1 and Figure 2 As shown. Both types of positive electrode plates have their own problems. Figure 1 The mesh current collector is prone to edge breakage during the production process, which affects the capacity of the positive electrode; Figure 2 While the bowl-shaped current collector effectively protects the positive electrode from damage during manufacturing, its current collection capacity remains unsatisfactory. Under high-current pulse discharge of 10mA, the battery's release capacity is low and the discharge time is short, failing to meet user needs. Therefore, a novel current collector structure for coin cells is needed to improve the capacity and capacity release rate of lithium-manganese dioxide coin cells under high-current pulse mode. Summary of the Invention

[0004] With the development of electronic information technology in recent years, higher requirements have been placed on the performance of batteries in all aspects, especially the requirements for high-current discharge capacity. For example, the IEC standard has added a 10mA high-current pulse performance requirement for the CR2032 lithium manganese button battery, specifically: 10mA discharge for 5 seconds, rest for 55 seconds, and continuous discharge until the battery voltage reaches 1.8V to cut off, requiring the battery to be able to discharge for at least 12.5 hours (that is, the average discharge time in 10mA mode is 12.5 hours, corresponding to a battery discharge capacity of 125mAh).

[0005] Currently, the discharge time of commonly used lithium-manganese dioxide button batteries in the market is generally 13~17 hours in 10mA high-current pulse mode (corresponding to a discharge capacity of 130~170mAh, with the released capacity only reaching 57.8%~75.6% of the designed capacity). The discharge time is too short, and the discharge capacity cannot meet the user's needs.

[0006] Research and analysis revealed that the low capacity release during a 10mA pulse discharge is due to a rapid increase in internal resistance during the later stages of discharge, fundamentally caused by insufficient electrolyte within the battery. Therefore, while ensuring good conductivity of the positive electrode, improving the electrolyte absorption rate of the positive electrode is crucial.

[0007] The purpose of this invention is to overcome the shortcomings of the prior art and provide a pinhole ring current collector, a positive electrode sheet with high liquid absorption rate, and a button battery.

[0008] In the first aspect, this utility model discloses a pinhole ring current collector, which adopts the following technical solution:

[0009] A pinhole ring current collector and a positive electrode with high liquid absorption rate using the current collector ring, comprising: a substrate and an annular ring extending upward from the periphery of the substrate, wherein the substrate is provided with liquid absorption holes and a plurality of pinhole holes arranged in a ring around the liquid absorption holes, and the pinhole holes protrude toward the side extending in the direction of the annular ring.

[0010] Preferably, the liquid suction hole is located on the same axis as the substrate.

[0011] Preferably, adjacent needle holes are radially staggered around the liquid absorption hole.

[0012] Preferably, the ratio of the diameter of the liquid absorption hole to the diameter of the substrate is (2±0.05~11±0.05):(15.9±0.05).

[0013] Preferably, the ratio of the diameter of a single pinhole to the diameter of the substrate is (0.8±0.05~1.0±0.05):(15.9±0.05).

[0014] Preferably, the ratio of the spacing between adjacent pinholes to the diameter of the substrate is (1.0~1.5):(15.9±0.05).

[0015] Preferably, the ratio of the height of the pinhole protrusion to the diameter of the substrate is (0.75~0.85):(15.9±0.05).

[0016] Preferably, the ratio of the height of the ring to the diameter of the substrate is (1.45±0.05):(15.9±0.05).

[0017] Secondly, this utility model discloses a positive electrode sheet with a high liquid absorption rate using this current collector ring, adopting the following technical solution:

[0018] A positive electrode with high liquid absorption rate includes the aforementioned pinhole ring current collector, the substrate of the pinhole ring current collector and the ring ring forming a receiving cavity, the receiving cavity containing positive electrode powder and electrolyte, the positive electrode powder being at least partially exposed in the liquid absorption hole, and the pinhole protrusion penetrating into the positive electrode powder.

[0019] Thirdly, this utility model discloses a button battery, which adopts the following technical solution:

[0020] A button battery includes a positive electrode cap, a pinhole ring current collector, a separator, a negative electrode sheet, and a negative electrode cap stacked sequentially. The substrate and the ring of the pinhole ring current collector form a receiving cavity. The receiving cavity contains positive electrode powder and electrolyte. At least part of the positive electrode powder is exposed in the liquid absorption hole, and the pinhole protrusion pierces into the positive electrode powder.

[0021] Compared with the prior art, the present invention has at least the following beneficial effects:

[0022] This invention addresses the problem that commonly used lithium-manganese dioxide button batteries have short discharge times and insufficient discharge capacity to meet user needs under 10mA high-current pulse mode. It proposes a novel pinhole ring current collector structure design. By setting up suction holes and several ring-shaped pinholes, conductivity is ensured while rapidly increasing the positive electrode's liquid absorption rate within the same immersion time. This prevents the battery's internal resistance from rising too quickly due to insufficient electrolyte during discharge, thereby simultaneously improving both battery capacity and capacity release rate. This solves the problem of short discharge time and low capacity release in traditional button batteries under 10mA high-current pulse mode. Attached Figure Description

[0023] Figure 1 This refers to the traditional mesh current collector and positive electrode in existing technologies;

[0024] Figure 2 This refers to the traditional bowl-shaped current collector and positive electrode in existing technologies;

[0025] Figure 3 This is a photograph of the pinhole ring current collector and the positive electrode plate of Embodiment 1 of this utility model;

[0026] Figure 4 The trend of liquid absorption rate of traditional bowl-shaped current collector positive electrode and novel needle-hole ring current collector positive electrode;

[0027] Figure 5 The image shows a through-hole ring current collector without pinholes and a physical diagram of the positive electrode plate.

[0028] Figure 6 The liquid absorption rate curves are shown for the positive electrodes of the current collector rings with and without pinholes.

[0029] Figure 7 3kOhm discharge curves of CR2032 batteries with and without pinholes;

[0030] Figure 8 The flow ring structure is provided in four alternative embodiments with different sizes and positions of the suction holes;

[0031] Figure 9 This is a front view of the positive electrode structure of the pinhole ring current collector according to another embodiment of the present invention;

[0032] Figure 10 for Figure 9 Side view.

[0033] Explanation of icon numbers:

[0034] 1. Substrate; 11. Liquid absorption hole; 12. Pinhole; 2. Ring; 3. Positive electrode powder. Detailed Implementation

[0035] To make the above-mentioned objectives, features and advantages of this utility model more apparent and understandable, the utility model will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0036] Example 1

[0037] A pinhole ring current collector and a positive electrode and a button cell using the current collector ring with high liquid absorption rate.

[0038] The pinhole ring current collector includes a substrate 1 and an annular ring 2 extending upward from the periphery of the substrate 1. The substrate 1 has a liquid absorption hole 11 and a plurality of pinholes 12 arranged annularly around the liquid absorption hole 11. The pinholes 12 protrude towards the side extending from the annular ring 2. The liquid absorption hole 11 and the substrate 1 are coaxial. Adjacent pinholes 12 in the pinhole ring current collector are radially staggered from the liquid absorption hole 11. The substrate diameter of the pinhole ring current collector is 15.9±0.05mm, the height of the annular ring is 1.45±0.05mm, the diameter of the liquid absorption hole is 10±0.05mm, the diameter of a single pinhole is 0.8±0.05mm, the height of the protruding pinhole is 0.75~0.85mm, the spacing between adjacent pinholes is 1.0~1.5mm, and the radial distance from each pinhole to the liquid absorption hole is 0.8~3mm.

[0039] The positive electrode includes the aforementioned pinhole ring current collector. The substrate 1 and the ring 2 of the pinhole ring current collector form a receiving cavity. The receiving cavity contains positive electrode powder 3 and electrolyte. At least part of the positive electrode powder 3 is exposed in the liquid absorption hole 11, and the pinhole hole 12 protrudes into the positive electrode powder.

[0040] The button cell includes a positive electrode cap, a positive electrode sheet with a pinhole ring current collector, a separator, a negative electrode sheet, and a negative electrode cap stacked in sequence.

[0041] The manufacturing process of the button cell battery in Example 1 includes the following steps:

[0042] (1) Prepare cathode powder according to existing processes;

[0043] (2) Take the positive electrode powder produced in the production line and make it into a pinhole ring current collector positive electrode, and control the powder weight to be 1.05g;

[0044] (3) After baking and cooling the positive electrode of the pinhole ring current collector to room temperature, the positive electrode of the pinhole ring current collector is soaked in electrolyte and the electrolyte absorption rate is tested in the drying room. The data values ​​are recorded and the results are shown in Table 1.

[0045] (4) The positive electrode with a pinhole ring current collector after soaking in liquid was used in the assembly and production of CR2032 lithium manganese button batteries. In the battery assembly, the lithium content was designed to be 225mAh. The results of 10mA high-current pulse discharge are shown in Table 2.

[0046] Comparative Example 1

[0047] A mesh current collector and a positive electrode and a button cell using the current collector.

[0048] The mesh current collector and positive electrode structure of Comparative Example 1 are shown in Figure 1. Figure 1 The manufacturing process of its button batteries includes the following steps:

[0049] (1) Prepare cathode powder according to existing processes;

[0050] (2) Take the positive electrode powder produced in the production line and make it into mesh current collector positive electrode sheets, and control the powder weight to be 1.05g;

[0051] (3) After baking and cooling the mesh current collector positive electrode to room temperature, the mesh current collector positive electrode is soaked in electrolyte for the same soaking time as in Example 1. The electrolyte absorption rate is tested in a drying room and the data values ​​are recorded. The results are shown in Table 1.

[0052] (4) The mesh current collector positive electrode after soaking in liquid was used in the assembly and production of CR2032 lithium manganese button batteries. In the battery assembly, the lithium content was designed to be 225mAh. The results of 10mA high-current pulse discharge are shown in Table 2.

[0053] Comparative Example 2

[0054] A bowl-shaped current collector and a positive electrode plate and a button cell using the current collector.

[0055] Comparative Example 2 shows the bowl-shaped current collector and the positive electrode. Figure 2 The manufacturing process of its button batteries includes the following steps:

[0056] (1) Prepare cathode powder according to existing processes;

[0057] (2) Take the positive electrode powder produced in the production line and roll it into a cup-shaped current collector positive electrode, controlling the powder weight to be 1.05g;

[0058] (3) After baking and cooling the bowl-shaped current collector positive electrode to room temperature, the bowl-shaped current collector positive electrode is soaked in electrolyte for the same soaking time as in Example 1. The electrolyte absorption rate is tested in a drying room and the data values ​​are recorded. The results are shown in Table 1.

[0059] (4) The bowl-shaped current collector positive electrode after soaking in liquid was used in the assembly production of CR2032 lithium manganese button batteries. In the battery assembly, the lithium usage was designed to be 225mAh. The results of 10mA high-current pulse discharge are shown in Table 2.

[0060] Table 1 Positive electrode liquid absorption rate

[0061]

[0062] Table 2 Capacity release under 10mA high-current pulse discharge (225mAh design)

[0063]

[0064] Compare the test results of each group in Tables 1 and 2, and Figure 4 It is known that, under the same positive electrode powder formulation, the positive electrode prepared using the needle-hole ring current collector of this invention has the highest liquid absorption rate. Furthermore, during a high-current 10mA pulse discharge, the capacity release rate of a traditional mesh positive electrode button cell is only about 60%, while the cup-shaped ring current collector positive electrode button cell performs better, reaching about 75%. The needle-hole ring current collector positive electrode button cell of this invention has the highest capacity release rate, exceeding 96%. This novel needle-hole ring current collector positive electrode design, by improving the liquid absorption rate of the positive electrode, ensures that the internal resistance of the button cell can be kept at a low level throughout the discharge process, thereby improving the problems of short discharge time and low capacity release under a 10mA high-current pulse.

[0065] In this invention, the central suction hole and the annular pinhole work synergistically. Theoretically, without the central large hole structure (all-around pinhole), the internal contact of the positive electrode would be improved, and the current collection effect of the ring would also increase. However, this is not actually the case. Experiments comparing the positive electrode plate of the pinhole ring of this invention with those of the all-around pinhole ring... Figure 2The resistance of the bowl-shaped current collector positive electrode was measured with one end of the probe attached to the bottom positive electrode powder and the other end attached to the positive electrode metal current collector ring; there was no difference between the two. This is because the positive electrode powder formulation contains a considerable proportion of conductive carbon material, and the current collector ring is designed to facilitate current collection and meet the requirements of the high expansion mechanism during discharge. Therefore, the concept of this invention lies in combining the design principles of traditional grid positive electrode current collectors and traditional bowl-shaped current collectors to propose the solution of this invention.

[0066] To better illustrate the synergistic effect between the central liquid absorption hole and the annular pinhole hole in the positive electrode of the pinhole ring current collector of this utility model, the following parallel comparative experiments are conducted to explore and verify the differences:

[0067] 1. Investigate the effect of the presence or absence of pinholes in the current collector ring on the positive electrode performance.

[0068] Figure 3 The images show a current collector ring with pinholes and a cathode sheet made from the cathode powder. Figure 5 The images show a current collector ring without pinholes and a cathode sheet after the cathode powder has been processed. Aside from the pinholes, the two types of cathode sheets are identical in terms of dimensional design parameters, cathode powder quantity, washing time, and other processes. A comparison of the cathode liquid absorption rates of the two cathode sheets with and without pinholes is shown below. Figure 6 A comparison of the 3kOhm discharge curves of two CR2032 button batteries, one with pinholes and one without, is shown in the image. Figure 7 .

[0069] Depend on Figure 6 and Figure 7 It is evident that adding a pinhole not only increases the amount of electrolyte absorbed but also improves conductivity. This results in a higher discharge plateau during the mid-discharge phase and a consistently high potential at the end of the discharge, thereby increasing the utilization rate of the negative electrode and improving battery capacity. Conversely, if only the absorbent hole is designed without the pinhole, the absorbent effect will be significantly reduced, and conductivity will also decrease noticeably. Therefore, a design balance between the pinhole and the absorbent hole is necessary to achieve optimal results.

[0070] 2. Investigate the influence of the size and layout of the liquid absorption holes on the performance of the positive electrode.

[0071] by Figure 3 Based on the shape of the central suction hole and the annular pinhole (substrate diameter 15.9 mm, suction hole diameter 10 mm), the suction rate decreased with every 1 mm decrease in the suction hole diameter. However, when the suction hole diameter continued to increase, the pinhole effect deteriorated, resulting in significant performance fluctuations. Specific test results are shown in Table 3 below.

[0072] Table 3. Distribution of positive electrode liquid absorption rate for different positive electrode ring wicking hole diameters and discharge capacity release of the corresponding assembled batteries under a 3 kOhm load.

[0073]

[0074] As can be seen from Table 3, the larger the size of the liquid absorption hole in the current collector structure of the above optional embodiments, the higher the liquid absorption rate of the positive electrode and the higher the battery capacity release rate. However, if the size of the liquid absorption hole exceeds a certain value, even if a liquid absorption hole is added on the basis of the current collector with pinhole, the effect is even worse than not setting a liquid absorption hole. This is because the protrusion of the pinhole needs a certain design height (0.75mm~0.85mm). If the liquid absorption hole is too large, it will affect the contact current collection effect of the pinhole penetrating the positive electrode. For the size of the lithium manganese button battery of model CR2032, the optimal diameter of the liquid absorption hole is 10mm. At this time, the current collection capacity and liquid absorption rate reach an ideal balance.

[0075] See Figure 8 Four alternative embodiments of the flow ring structure with four different sizes and positions of the suction holes, wherein, Figure 8 a and Figure 8 The suction holes in component b are the same size but in different positions. Figure 8 a and Figure 8 c, Figure 8 The positions of the 'd' points are consistent, but the sizes of the suction holes are inconsistent. From the perspective of suction rate, the suction rate is: Example 1> Figure 8 a> Figure 8 Chinese Figure 8 c> Figure 8 In the middle d, judging from the discharge curve of the battery at 3kOhm, the performance order is as follows: Example 1 > Figure 8 a> Figure 8 Chinese Figure 8 c> Figure 8 In addition, when in d, Figure 8 Add pinholes to the rings, following the same sequence. It is evident that, within a certain parameter design range, battery performance is positively correlated with the liquid absorption rate, while... Figure 8 a and Figure 8 As shown in result b, although the size of the liquid absorption holes is the same, the position of the liquid absorption holes affects the discharge performance of the battery. This is because the discharge of the battery is a uniform lithium consumption, so the uniformity of current collection is beneficial to the discharge performance of the battery. The position of the liquid absorption holes not only affects the uniform distribution of the electrolyte, but also affects the annular arrangement of the pinhole holes and the positive electrode coaxially. Therefore, the position of the liquid absorption holes is preferably designed to be on the same axis as the positive electrode substrate.

[0076] 3. Investigate the effect of pinhole layout on positive electrode performance.

[0077] See Figure 9The pinhole ring current collector is another optional embodiment of this utility model. The only difference between it and embodiment 1 is that the radial distance from each pinhole to the liquid absorption hole of the pinhole ring current collector is the same, about 2 mm. Although the current collection effect is similar to that of embodiment 1, the design of adjacent pinholes being radially staggered at the liquid absorption hole in embodiment 1 is more conducive to reducing the adverse effects of pinhole drilling on strength. This results in better quality of positive electrode powder, higher yield of button cell production, and significant improvement in battery life and performance stability.

[0078] The above series of case studies demonstrate that, under the same weight of positive electrode powder, the electrolyte absorption rate of the positive electrode using the needle-hole ring current collector of this invention can be increased by 30% compared to the traditional bowl-shaped current collector positive electrode, and the capacity release rate is increased by about 20%. Furthermore, the special design requirements between the absorption hole and the needle hole of this invention enable a balance between the current collection capacity and the absorption rate of the positive electrode, thereby achieving a significant improvement in the capacity and capacity release rate of the button battery. This solves the problem of short discharge time and insufficient discharge capacity to meet user needs under current pulse mode.

[0079] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and not to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model. This utility model can be applied to the production of positive electrodes for lithium manganese button batteries of all sizes by adjusting the size and specifications.

Claims

1. A needle eye ring fluid collector characterized by, The application relates to a needle eye ring current collector, which comprises a substrate and a ring arranged on the periphery of the substrate and extending upward, a liquid suction hole and a plurality of needle eye holes arranged in a ring around the periphery of the liquid suction hole are arranged on the substrate, and the needle eye holes protrude towards one side of the extending direction of the ring.

2. The needle eye ring fluid of claim 1, wherein, The liquid suction hole and the substrate are coaxial.

3. The needle eye ring fluid of claim 1, wherein, The adjacent needle eye holes are arranged radially staggered around the periphery of the liquid suction hole.

4. The needle eye ring fluid of any one of claims 1 to 3, wherein, The ratio of the diameter of the liquid suction hole to the diameter of the substrate is (2+ / -0.05 to 11+ / -0.05):(15.9+ / -0.05).

5. The needle eye ring fluid of any one of claims 1-3, wherein, The ratio of the diameter of a single needle eye hole to the diameter of the substrate is (0.8+ / -0.05 to 1.0+ / -0.05):(15.9+ / -0.05).

6. The needle eye ring fluid of any one of claims 1-3, wherein, The ratio of the distance between the adjacent needle eye holes to the diameter of the substrate is (1.0 to 1.5):(15.9+ / -0.05).

7. The needle eye ring fluid of any one of claims 1-3, wherein, The ratio of the protruding height of the needle eye hole to the diameter of the substrate is (0.75 to 0.85):(15.9+ / -0.05).

8. The needle eye ring fluid of any one of claims 1-3, wherein, The ratio of the height of the ring to the diameter of the substrate is (1.45+ / -0.05):(15.9+ / -0.05).

9. A high-solution positive electrode sheet, characterized by, The needle eye ring current collector comprises the substrate and the ring of any one of claims 1-8, the substrate and the ring form a containing cavity, the containing cavity contains positive electrode powder and electrolyte, the positive electrode powder is at least partially exposed to the liquid suction hole, and the protruding needle eye hole penetrates into the positive electrode powder.

10. A coin cell battery characterized by, The needle eye ring current collector comprises the substrate and the ring of any one of claims 1-8, the substrate and the ring form a containing cavity, the containing cavity contains positive electrode powder and electrolyte, the positive electrode powder is at least partially exposed to the liquid suction hole, and the protruding needle eye hole penetrates into the positive electrode powder.

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