Alkaline zinc-manganese battery with composite positive electrode and preparation method of alkaline zinc-manganese battery

Abstract

The invention discloses a composite positive electrode alkaline zinc-manganese battery and a preparation method thereof, and relates to the technical field of zinc-manganese batteries, a traditional single positive electrode ring is improved, a high-performance and high-cost EMD is arranged in an inner ring area, and a low-performance and low-cost CMD is arranged in an outer ring area, so that the high-load discharge capacity of the battery is ensured, and the service life of the battery is prolonged. According to the present invention, the overall discharge capacity under the medium-low load is ensured, the performance optimization under the limited cost is achieved, the low-price CMD is used as the main active material in the outer ring, the high-price EMD consumption is substantially reduced, the material cost of the battery is significantly reduced, and the basic discharge capacity and the safety performance of the battery are effectively maintained. According to the preparation of the composite positive electrode alkaline zinc-manganese battery, the compatibility of the existing mature production process is maintained, the improvement of the production process is concentrated on the mold of the front-end ring pressing process and the ring entering program optimization, the equipment transformation at the subsequent battery assembly end is avoided, and the cost and difficulty of technology upgrading are reduced.

Description

A composite positive electrode alkaline zinc-manganese battery and its preparation method Technical Field

[0001] This invention relates to the field of zinc-manganese battery technology, and in particular to a composite positive electrode alkaline zinc-manganese battery and its preparation method. Background Technology

[0002] Alkaline zinc-manganese batteries are among the most popular primary batteries in the world due to their excellent discharge performance, long storage time, and low cost. Electrolytic manganese dioxide (EMD) is produced by electrolysis using manganese sulfate solution as the electrolyte. Manganese dioxide is generated at the anode through an oxidation reaction and deposited on the electrode surface. The production process requires precise control of parameters such as electrolyte composition, temperature, and current density. Its internal structure is highly ordered, with high theoretical density and high discharge capacity. Chemical manganese dioxide (CMD), on the other hand, is prepared through chemical reactions, such as reacting manganese ore with sulfuric acid to produce manganese sulfate, which is then converted to manganese dioxide through oxidation. It has a higher initial voltage, larger specific surface area, and higher chemical activity, but its internal structure is disordered and less uniform, resulting in higher internal resistance and lower discharge capacity.

[0003] EMD, as the main material in current alkaline manganese batteries, has a higher cost compared to CMD due to its higher raw material costs, energy consumption costs, and environmentally friendly production costs. Zinc-manganese batteries made using EMD are therefore more expensive. Currently, there are two main methods to reduce the cost of alkaline batteries: one is to reduce the amount of active material, which leads to a significant decrease in battery performance and can also affect battery safety; the other is to mix and use expensive EMD with inexpensive CMD, which results in poor overall battery capacity and continuous discharge capability. Summary of the Invention

[0004] The purpose of this invention is to address the problem that existing technologies, which use electrolytic manganese dioxide (EMD) and chemical manganese dioxide (CMD) mixed doping as the positive electrode to reduce the cost of alkaline batteries, suffer from poor overall battery capacity and continuous discharge capability. This invention provides a composite positive electrode alkaline zinc-manganese battery and its preparation method.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A composite positive electrode alkaline zinc-manganese battery includes: a battery casing, a battery positive electrode, a separator, a negative electrode current collector, and a negative electrode zinc paste electrolyte; the battery positive electrode includes a positive inner ring and a positive outer ring arranged coaxially; the positive outer ring is located radially outside the positive inner ring; the positive inner ring uses electrolytic manganese dioxide as the positive electrode material; the positive outer ring uses chemical manganese dioxide as the positive electrode material.

[0007] The composite positive electrode alkaline zinc-manganese battery of the present invention, by setting a composite positive electrode including an inner positive electrode ring and an outer positive electrode ring, allows the inner positive electrode ring, with electrolytic manganese dioxide as the positive electrode material, to undergo a high-current discharge reaction with the adjacent negative electrode zinc first, ensuring the high power output capability of the battery. Complementarily, the outer positive electrode ring, with chemical manganese dioxide as the positive electrode material, is located radially outside the inner positive electrode ring. As the battery energy is consumed, the chemical manganese dioxide slowly and fully participates in the reaction, enabling a longer-lasting continuous low-current discharge, maintaining the overall continuous discharge capability of the battery. Therefore, through the above-mentioned arrangement of the present invention, both high power output capability and low-current continuous discharge capability in the later stage are ensured, thereby improving the overall discharge output capability of the alkaline zinc-manganese battery. Compared with a single positive electrode ring battery using electrolytic manganese dioxide as the positive electrode material, the comprehensive discharge performance reaches 98.4% of that of a single positive electrode ring battery, while the cost is significantly reduced, improving the economic efficiency of zinc-manganese battery production.

[0008] Preferably, in the composite positive electrode alkaline zinc-manganese battery of the present invention, the mass ratio of the positive electrode material in the inner ring to the positive electrode material in the outer ring is 3:2.

[0009] As a preferred embodiment of the present invention, by precisely controlling the proportion of electrolytic manganese dioxide and chemical manganese dioxide used as positive electrode materials, positive electrode inner ring and positive electrode outer ring with equivalent ring diameter, thickness and proportion of usage are obtained, thereby achieving the best comprehensive discharge performance while reducing the cost of positive electrode materials for alkaline batteries.

[0010] Preferably, in the composite positive electrode alkaline zinc-manganese battery of the present invention, the mass ratio of the positive electrode material in the inner ring to the positive electrode material in the outer ring is 1:1.

[0011] As a preferred embodiment of the present invention, by precisely controlling the proportion of electrolytic manganese dioxide and chemical manganese dioxide used as positive electrode materials, positive electrode inner ring and positive electrode outer ring with equivalent ring diameter, thickness and proportion of usage are obtained. This achieves a relative balance between production cost and performance while improving overall discharge performance, thereby further improving the economic benefits of composite positive electrode alkaline zinc-manganese batteries.

[0012] Preferably, in the composite positive electrode alkaline zinc-manganese battery of the present invention, both the inner positive electrode ring and the outer positive electrode ring are axially stacked from at least three positive electrode ring units of equal height.

[0013] As a preferred embodiment of the present invention, by setting a positive electrode ring unit, the positive electrode ring of the battery can be easily assembled with minimal impact on the battery discharge reaction, thereby improving the convenience and efficiency of battery production.

[0014] Preferably, in the composite positive electrode alkaline zinc-manganese battery of the present invention, the mass ratio of electrolytic manganese dioxide as the positive electrode material to the auxiliary additive is 9:1; the mass ratio of chemical manganese dioxide as the positive electrode material to the auxiliary additive is 9:1.

[0015] As a preferred embodiment of the present invention, by controlling the electrolytic manganese dioxide and chemical manganese dioxide as positive electrode materials, and having the same mass ratio to the auxiliary additives, and both being 9:1, the uniformity of the positive electrode discharge performance can be maintained, the influence of the auxiliary additives on the discharge performance can be further reduced, and the overall discharge performance can be further improved.

[0016] To achieve the objectives of this invention, another technical solution is provided:

[0017] A method for preparing a composite positive electrode alkaline zinc-manganese battery includes the following steps:

[0018] S1. The pre-prepared electrolytic manganese dioxide positive electrode mixture is pressed into the inner ring of the positive electrode using a matching mold; the pre-prepared chemical manganese dioxide positive electrode mixture is pressed into the outer ring of the positive electrode using a matching mold.

[0019] S2. First, axially insert the outer ring of the positive electrode into the housing, and then axially insert the inner ring of the positive electrode into the inner side of the outer ring of the positive electrode.

[0020] The method for preparing the composite positive electrode alkaline zinc-manganese battery described in this invention achieves a composite positive electrode alkaline zinc-manganese battery with low preparation cost and high overall discharge performance, while maintaining maximum compatibility with existing mature production processes. The improvements in the production process are concentrated on optimizing the mold and ring insertion procedure in the front-end ring pressing process, avoiding the need for subsequent equipment modifications at the battery assembly end, and reducing the cost and difficulty of technology upgrades.

[0021] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0022] 1. The composite cathode alkaline zinc-manganese battery described above, by functionally partitioning the traditional single cathode ring, arranges the high-performance, high-cost EMD in the inner ring area and the low-performance, low-cost CMD in the outer ring area, while ensuring the battery's high load discharge capacity and overall discharge capacity under medium and low loads, achieves performance optimization under limited cost.

[0023] 2. The composite positive electrode alkaline zinc-manganese battery described above significantly reduces the amount of expensive EMD by using lower-priced CMD as the main active material in the outer ring, thereby significantly reducing the material cost of the battery while effectively maintaining the battery's basic discharge capacity and safety performance.

[0024] 3. The preparation method of the composite positive electrode alkaline zinc-manganese battery of the present invention maintains compatibility with existing mature production processes to the greatest extent. The improvement of the production process focuses on the optimization of the mold and ring insertion process in the front-end ring pressing process, avoiding the need for equipment modification at the subsequent battery assembly end, and reducing the cost and difficulty of technology upgrade. Attached Figure Description

[0025] Figure 1 is a vertical cross-sectional schematic diagram of the composite positive electrode alkaline zinc-manganese battery structure of the present invention;

[0026] Figure 2 is a three-dimensional structural diagram of the inner and outer rings of the positive electrode of the present invention;

[0027] Figure 3 is a schematic flowchart of the preparation method of the composite positive electrode alkaline zinc-manganese battery of the present invention;

[0028] Icons: 1. Battery casing; 2. Battery positive electrode; 21. Positive electrode inner ring; 22. Positive electrode outer ring; 3. Separator tube; 4. Negative electrode zinc paste electrolyte; 5. Negative electrode current collector; 51. Sealing ring; 52. Current collector pin; 53. Negative terminal. Detailed Implementation

[0029] The present invention will now be described in detail with reference to the accompanying drawings.

[0030] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0031] Example 1:

[0032] This embodiment discloses a composite positive electrode alkaline zinc-manganese battery, including: a battery casing 1, a battery positive electrode 2, a separator 3, a negative electrode current collector 5, and a negative electrode zinc paste electrolyte 4; the battery positive electrode 2 includes a positive inner ring 21 and a positive outer ring 22 arranged coaxially; the positive outer ring 22 is located radially outside the positive inner ring 21; the positive inner ring 21 uses electrolytic manganese dioxide as the positive electrode material; the positive outer ring 22 uses chemical manganese dioxide as the positive electrode material.

[0033] The battery described in this embodiment includes assembly components of a conventional battery, capable of realizing the basic functions of battery discharge, energy storage, and conductivity. The battery casing 1 can be a conventional steel casing. Referring to Figure 1, the upper end of the steel casing is open. The positive electrode of the battery includes a positive outer ring 22 and a positive inner ring 21. The negative electrode current collector 5 closes the upper opening of the steel casing. The positive outer ring 22 and the positive inner ring 21 overlap within the steel casing. The positive outer ring 22 and the positive inner ring 21 are concentric hollow cylinders. The positive outer ring 22 is tightly attached to the inner wall of the steel casing, and the positive inner ring 21 is tightly attached to the separator cylinder 3. The hollow cylinder formed by the positive outer ring 22 and the positive inner ring 21 forms a cavity coaxial with the steel casing, and the cylindrical separator cylinder 3 is located within the cavity. The separator cylinder 3 is wound into a hollow cylinder, and the bottom of the separator cylinder 3 is sealed using a hot-sealing process. The negative electrode zinc paste electrolyte 4 is filled inside the separator cylinder 3.

[0034] It should be noted that, unlike the discharge reaction of a mixed cathode material with doped raw materials, in which two or more doped cathode materials undergo discharge reaction simultaneously, the composite cathode described in this invention is understood to be capable of participating in the overall discharge reaction of the battery. For example, one cathode material participates in the discharge reaction first, while another cathode material participates in the discharge reaction later.

[0035] The positive electrode 2 of the battery described in this invention includes an inner positive electrode ring 21 and an outer positive electrode ring 22. The outer positive electrode ring 22 and the inner positive electrode ring 21 can be arranged in a conventional way for the positive electrode 2 rings of the battery. In this preferred embodiment, as shown in Figures 1 and 2, both the inner positive electrode ring 21 and the outer positive electrode ring 22 are axially stacked from at least three positive electrode ring units of equal height.

[0036] Specifically, in this invention, the mass ratio of electrolytic manganese dioxide as the positive electrode material to the auxiliary additive is 9:1; the mass ratio of chemical manganese dioxide as the positive electrode material to the auxiliary additive is also 9:1. The amount of auxiliary additive includes, but is not limited to, one or more of graphite, electrolyte, mold release agent, and polyethylene, and its specific composition can be adjusted according to requirements.

[0037] In this embodiment, the EMD is placed in the inner ring and the CMD is placed in the outer ring. When the battery discharges at a high current, the reaction preferentially consumes the EMD adjacent to the negative electrode zinc paste electrolyte 4, ensuring the high power output capability of the battery. When the battery discharges at a medium or low current, the CMD can slowly and fully participate in the reaction, so that the battery can maintain excellent overall discharge performance while reducing material costs.

[0038] The present invention allows for the creation of EMD inner rings and CMD outer rings with different mass ratios by setting rings of the same height and matching their bottom radii. For example, the inner radius R1 of the positive electrode outer ring 22 is slightly larger than the outer radius r2 of the positive electrode inner ring 21. A pre-set positive electrode ring assembly gap R1-r2 ≤ 0.1 mm is used. After the battery is filled with electrolyte, the positive electrode ring absorbs the electrolyte and expands, closing this gap. This gap design aims to prevent severe friction between the positive electrode outer ring 22 and the positive electrode inner ring 21 during ring insertion, which could damage the positive electrode ring structure and affect battery performance, thus improving assembly smoothness. It also avoids excessively large gaps that could affect the electronic conduction efficiency of the positive electrode outer ring 22 and the positive electrode inner ring 21.

[0039] It should be noted that the current collector described in this invention can adopt several features of a conventional alkaline zinc-manganese battery. Preferably, the current collector includes: a sealing ring 51, a current collecting needle 52, and a negative terminal 53; the zinc paste electrolyte can be the zinc paste and electrolyte material commonly used in alkaline zinc-manganese batteries; for example, zinc paste and electrolyte that are compatible with the positive electrode.

[0040] The composite cathode alkaline zinc-manganese battery described in this embodiment can be prepared using the method described in Example 4. Referring to the battery discharge performance test results in Table 1, it can be concluded that this invention achieves an optimized balance between cost and performance by functionally partitioning the traditional single cathode ring. High-performance, high-cost EMD is placed in the inner ring region, while low-performance, low-cost CMD is placed in the outer ring region. This ensures both high-load discharge capability and overall discharge capacity under medium and low loads, achieving optimal performance within a limited cost. Furthermore, it significantly reduces the battery's material cost by using lower-priced CMD as the main active material in the outer ring, drastically reducing the amount of higher-priced EMD. Calculations show that compared to similar batteries using a traditional single EMD cathode material as the cathode ring, this invention can reduce the cost of manganese dioxide material by approximately 25%, while effectively maintaining the battery's basic discharge capability and safety performance. This invention brings gains by setting the outer positive electrode ring 22 and the inner positive electrode ring 21, while maintaining maximum compatibility with existing mature production processes. Its main changes are concentrated on the optimization of the mold and ring insertion process in the front-end ring pressing process, avoiding the need for subsequent equipment modification at the battery assembly end, and reducing the cost and difficulty of technology upgrades.

[0041] Comparative Example 1:

[0042] This comparative example demonstrates an alkaline zinc-manganese battery. The difference between this comparative example and Example 1 is that the positive electrode is not divided into inner and outer rings, but uses a single positive electrode ring, and all positive electrode rings use EMD. The mass fractions of manganese dioxide and auxiliary additives are still 90% and 10%, respectively.

[0043] It should be noted that although a single positive electrode ring EMD can achieve 100% overall discharge performance as a positive electrode material, it is expensive; while the overall discharge performance of traditional alkaline zinc-manganese batteries that use a positive electrode mixture doped with EMD and CMD as a single positive electrode ring is less than 80%~90%.

[0044] Example 2:

[0045] The positive electrode 2 of the composite positive electrode alkaline zinc-manganese battery disclosed in this embodiment has the same structure as the embodiment, and the positions of the inner positive electrode ring 21 and the outer positive electrode ring 22 are the same. It is optimized based on embodiment 1, with the mass ratio of the positive electrode material in the inner positive electrode ring 21 to the positive electrode material in the outer positive electrode ring 22 being 1:1. Specifically, the apparent specific gravity of the positive electrode mixture in the outer positive electrode ring 22 and the inner positive electrode ring 21 is approximately equal, that is, the mass per unit volume of the inner positive electrode ring 21 and the outer positive electrode ring 22 is approximately equal. For example, the bottom area of ​​the inner positive electrode ring 21: the bottom area of ​​the outer positive electrode ring 22 ≈ 1:1; thereby controlling the total EMD:CMD ratio to ≈ 1:1. Referring to Table 1, the battery discharge performance tests of Example 2 and Comparative Example 2 show that Comparative Example 2, which uses EMD as the positive electrode material in the outer ring 22 and CMD as the positive electrode material in the inner ring 21, exhibits a significantly lower overall discharge capacity compared to Example 2, at only 75.7%. Furthermore, the high-current discharge of Comparative Example 2 is significantly affected. Therefore, by placing the highly active CMD in the outer ring and the high-capacity EMD in the inner ring through Examples 1, 2, 3, or 4, superior overall performance can be achieved.

[0046] Comparative Example 2:

[0047] The difference between this comparative example and Example 2 is that the positive electrode materials of the inner positive electrode ring 21 and the outer positive electrode ring 22 are interchanged. That is, the positive electrode material of the outer positive electrode ring 22 is EMD, and the positive electrode material of the inner positive electrode ring 21 is CMD. Specifically, the total height of the positive electrode rings in Example 2 and Comparative Example 2 is the same.

[0048] Example 3:

[0049] In actual production, the positive and negative electrode formulations and active material mass of the battery are usually adjusted according to customer needs and specific discharge requirements. The mass ratio of the positive electrode material in the inner ring 21 to the outer ring 22 is optimized. Based on Example 1, the structure and assembly position of the inner and outer rings 21 and 22 are the same as in Example 1. Preferably, the mass ratio of the positive electrode material in the inner ring 21 to the outer ring 22 is 2:3. Referring to the comprehensive discharge performance test results in Table 1, although this example further reduces costs compared to Example 2, it affects the discharge capacity. Although it can achieve a discharge performance higher than 95%, the overall discharge performance is not as good as Examples 2 and 4.

[0050] Example 4:

[0051] In Example 1, the mass ratio of the positive electrode material in the inner ring 21 to the positive electrode material in the outer ring 22 is optimized. Based on Example 1, the structure and assembly position of the inner ring 21 and the outer ring 22 are the same as in Example 1. It can be achieved by referring to Example 1. In this example, the mass ratio of the positive electrode material in the inner ring 21 to the positive electrode material in the outer ring 22 is 3:2.

[0052] Referring to the battery discharge performance test results in Table 1, the overall discharge performance of the battery prepared in this embodiment is close to the overall discharge performance of the positive electrode material mass ratio of 1:1 in Example 2. Comprehensive analysis shows that an EMD:CMD ratio of around 1:1 is the best balance point between performance and cost.

[0053] The present invention conducted discharge performance tests on the alkaline zinc-manganese batteries of the above embodiments and comparative examples. Nine alkaline zinc-manganese batteries from each of Examples 2, 3, and 4, and Comparative Examples 1 and 2 were aged at 45°C for 2 days, and their discharge performance was tested and the average value was taken. The test items were in accordance with IEC standards. The test results are shown in Table 1. The overall discharge performance was calculated with Comparative Example 1 as 100% of the baseline. Overall discharge performance = average[(single discharge regime of the embodiment) / (corresponding discharge performance of the comparative example)] × 100%.

[0054] Table 1: Average Data of Battery Discharge Performance Test Results

[0055]

[0056] Example 5:

[0057] This embodiment describes a method for preparing a composite positive electrode alkaline zinc-manganese battery, capable of preparing the composite positive electrode alkaline zinc-manganese battery as described in Embodiment 1, Embodiment 2, or Embodiment 3, comprising the following steps:

[0058] S1. The pre-prepared electrolytic manganese dioxide positive electrode mixture is pressed into the inner ring 21 of the positive electrode using a matching mold; the pre-prepared chemical manganese dioxide positive electrode mixture is pressed into the outer ring 22 of the positive electrode using a matching mold.

[0059] S2. First, axially insert the outer ring 22 of the positive electrode into the housing, and then axially insert the inner ring 21 of the positive electrode into the inner side of the outer ring 22 of the positive electrode.

[0060] Specifically, in this embodiment, manganese dioxide is mixed with auxiliary additives, and the desired positive electrode compound is obtained through steps such as crushing, stirring, pressing, granulation, and sieving. Specifically, the pre-made CMD positive electrode compound and EMD positive electrode compound are pressed into rings using their respective molds, thus obtaining the outer positive electrode ring 22 and the inner positive electrode ring 21. The molds used for the inner positive electrode ring 21 and the outer positive electrode ring 22 are different, and the mold dimensions can be adjusted according to requirements. During battery assembly, following the concentric assembly principle of outside to inside, the pressed CMD outer ring is first inserted into the steel shell and made to fit tightly against the shell wall; subsequently, the pressed EMD inner ring is concentrically inserted into the already positioned CMD outer ring.

[0061] Example 6:

[0062] This embodiment discloses an LR6 type battery. Combining the conventional preparation steps of an LR6 type battery, the LR6 type battery as described in Example 1 is prepared using the preparation method of a composite positive electrode alkaline zinc-manganese battery as described in Example 4.

[0063] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A composite positive electrode alkaline zinc-manganese battery, comprising: The battery casing (1), battery positive electrode (2), separator tube (3), negative electrode current collector (5), and negative electrode zinc paste electrolyte (4) are characterized in that the battery positive electrode (2) includes a positive inner ring (21) and a positive outer ring (22) arranged coaxially; the positive outer ring (22) is located radially outside the positive inner ring (21); the positive inner ring (21) uses electrolytic manganese dioxide as the positive electrode material; and the positive outer ring (22) uses chemical manganese dioxide as the positive electrode material.

2. The composite positive electrode alkaline zinc-manganese battery according to claim 1, characterized in that, The mass ratio of the positive electrode material in the inner ring (21) to the positive electrode material in the outer ring (22) is 3:

2.

3. The composite positive electrode alkaline zinc-manganese battery according to claim 1, characterized in that, The mass ratio of the positive electrode material in the inner ring (21) to the positive electrode material in the outer ring (22) is 1:

1.

4. The composite positive electrode alkaline zinc-manganese battery according to claim 1, characterized in that, Both the inner positive ring (21) and the outer positive ring (22) are axially stacked from at least three positive ring units of equal height.

5. The composite positive electrode alkaline zinc-manganese battery according to claim 1, characterized in that, The mass ratio of electrolytic manganese dioxide as the positive electrode material to the auxiliary additive is 9:1; the mass ratio of chemical manganese dioxide as the positive electrode material to the auxiliary additive is 9:

1.

6. A method for preparing a composite positive electrode alkaline zinc-manganese battery, characterized in that, The preparation of the composite positive electrode alkaline zinc-manganese battery as described in any one of claims 1-5 includes the following steps: S1, pressing the pre-prepared electrolytic manganese dioxide positive electrode mixture into the positive electrode inner ring (21) using a matching mold; pressing the pre-prepared chemical manganese dioxide positive electrode mixture into the positive electrode outer ring (22) using a matching mold; S2, first axially inserting the positive electrode outer ring (22) into the housing, and then axially inserting the positive electrode inner ring (21) into the inner side of the positive electrode outer ring (22).

7. An LR6 type battery, characterized in that, The composite positive electrode alkaline zinc-manganese battery was prepared using the method described in claim 6.

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