A lithium-manganese battery cell, a preparation method thereof and a lithium-dioxide-manganese battery

Abstract

The application provides a lithium-manganese battery cell, a preparation method thereof and a lithium-manganese dioxide battery, the lithium-manganese battery cell comprising a first positive electrode sheet, a second positive electrode sheet, a negative electrode sheet, a diaphragm and an electrolyte, the diaphragm separating the negative electrode sheet from the first positive electrode sheet and the second positive electrode sheet; the negative electrode sheet, the diaphragm and the first positive electrode sheet being sequentially stacked, the second positive electrode sheet having a ring-shaped hollow structure, the second positive electrode sheet being sleeved on the outer side of the first positive electrode sheet and the negative electrode sheet, a first gap being left between the second positive electrode sheet and the first positive electrode sheet, and a second gap being left between the negative electrode sheet and the first positive electrode sheet. The lithium-manganese battery cell structure designed by the application can increase the amount of internal electrolyte and avoid the problem of poor contact between the positive electrode and the negative electrode at the end of discharge, so that the battery can realize long-term and effective discharge. The lithium-manganese battery prepared based on this has good application prospects when applied to large current.

Description

A lithium manganese battery cell, its preparation method, and a lithium manganese dioxide battery Technical Field

[0001] This invention belongs to the field of batteries, specifically relating to a lithium manganese battery cell, its preparation method, and a lithium manganese dioxide battery. Background Technology

[0002] Lithium-manganese dioxide batteries (referred to as lithium-manganese batteries) are primary lithium batteries (non-rechargeable). They use metallic lithium as the negative electrode and manganese dioxide as the positive electrode, separated by a non-woven fabric separator. The positive and negative electrodes are arranged in disc-like shapes on the top and bottom of the separator, respectively. Compared to other lithium batteries, their material and manufacturing costs are relatively low, and they offer excellent safety. Therefore, they are the most widely used commercial lithium batteries in the world today.

[0003] For lithium-manganese batteries, during discharge, the electrolyte and negative electrode are gradually consumed, while the positive electrode expands. This phenomenon determines that the current is unstable or even the discharge is abnormal at the end of the discharge. Existing positive and negative electrode disc stacked designs can meet the needs of low-current continuous discharge applications. For example, CN107785534A discloses a negative electrode top of a lithium-manganese button cell, a lithium-manganese button cell, and a processing method. The lithium-manganese button cell includes a positive electrode cup, a negative electrode top, a sealing ring, lithium metal, a positive electrode cake, a separator, and an electrolyte. The positive electrode cake and lithium metal are separated by the separator, and the positive electrode cup and negative electrode top are insulated by the sealing ring. The electrolyte fills the cavity formed by the negative electrode top and the positive electrode cup. The negative electrode top includes a top and a peripheral part, and the peripheral part includes an integrally connected annular inner wall and a flanged wall. CN217562682U provides a lithium manganese button battery, including a battery casing. The battery casing includes a negative electrode cover and a positive electrode cover disposed opposite to each other. A positive electrode sheet, a separator, and a negative lithium electrode sheet are stacked sequentially in the battery casing along the axial direction from the positive electrode cover to the negative electrode cover. The separator completely separates the positive electrode sheet and the negative lithium electrode sheet. The separator is a multilayer structure formed by stacking at least two separator sheets, and the pore size of each separator sheet is 48-50μm.

[0004] In summary, the battery structure designed above has lower requirements for the contact between the positive and negative electrodes and the amount of electrolyte during low-current discharge at the end of the period, but its performance is not good when used with high current.

[0005] Therefore, designing a novel lithium manganese battery cell structure to increase the internal space and electrolyte volume is an urgent technical problem to be solved. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a lithium-manganese battery cell, its preparation method, and a lithium manganese dioxide battery. The present invention designs a novel lithium-manganese battery cell structure that not only increases the internal space of the cell and the amount of internal electrolyte, but also improves the contact between the positive and negative electrodes at the end of discharge, avoiding the poor contact problem caused by the expansion of the positive electrode and the reduction of the negative electrode at the end of discharge, thus enabling the battery to discharge effectively and for a longer period. The lithium-manganese battery prepared based on this design performs well under high current conditions and has promising application prospects.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a lithium manganese battery cell, the lithium manganese battery cell comprising a first positive electrode, a second positive electrode, a negative electrode, a separator, and an electrolyte, wherein the separator separates the negative electrode from the first positive electrode and the negative electrode from the second positive electrode;

[0009] The negative electrode, the separator, and the first positive electrode are stacked in sequence. The second positive electrode has a ring-shaped hollow structure. The second positive electrode is sleeved on the outside of the first positive electrode and the negative electrode. A first gap is left between the second positive electrode and the first positive electrode, and a second gap is left between the negative electrode and the first positive electrode.

[0010] This invention designs a novel lithium-manganese battery cell structure that not only increases the internal space and electrolyte volume of the cell, but also improves the contact between the positive and negative electrodes at the end of discharge. This avoids the poor contact problem caused by the expansion of the positive electrode and the reduction of the negative electrode at the end of discharge, enabling the battery to achieve sustained and effective discharge. The lithium-manganese battery prepared based on this design performs well under high current conditions and has good application prospects.

[0011] In this invention, a first gap is left between the second positive electrode and the first positive electrode, and a second gap is left between the negative electrode and the first positive electrode. The purpose is to leave a certain space for the electrolyte, thereby increasing the electrolyte storage capacity, so that the cell can fully utilize the positive and negative electrode capacities and improve the cell's end-of-life pulse capability.

[0012] Preferably, the ratio of the diameter of the negative electrode, the inner diameter of the second positive electrode, and the diameter of the first positive electrode is (8-9.7):(9.6-11.4):(8.8-10.45), wherein the diameter of the negative electrode, in the range of "8-9.7", can be, for example, 8, 8.2, 8.4, 8.6, 8.8, 9, 9.2, 9.4, or 9.7; the inner diameter of the second positive electrode, in the range of "9.6-11.4", can be, for example, 9.6, 9.8, 10, 10.2, 10.4, 10.6, 10.8, 11, 11.2, or 11.4; and the diameter of the first positive electrode, in the range of "8.8-10.45", can be, for example, 8.8, 9, 9.2, 9.4, 9.6, 9.8, 10, 10.2, 10.4, or 10.45.

[0013] In this invention, if the ratio of the diameter of the negative electrode to the inner diameter of the second positive electrode is too small, that is, if the diameter of the negative electrode is too small, the gap between the two will be too large, and the positive electrode will shift during assembly (to the left or right, and will not make good contact with the negative electrode); if the ratio of the diameter of the negative electrode to the inner diameter of the second positive electrode is too large, the gap between the two will be too small, and the positive electrode will not be able to completely fit the negative electrode during assembly, resulting in abnormalities such as powder shedding, and the cell is prone to internal short circuit.

[0014] In this invention, if the ratio of the inner diameter of the second positive electrode to the diameter of the first positive electrode is too large, that is, the diameter of the first positive electrode is too small, the gap between the two will be too large, and the first positive electrode will sway within the positive electrode ring, failing to completely cover the negative electrode and react with it; if the ratio of the inner diameter of the second positive electrode to the diameter of the first positive electrode is too small, that is, the diameter of the first positive electrode is too large, the gap between the two will be too small, making it easy for powder to fall off during assembly, resulting in low pressure, and also hindering the absorption of electrolyte.

[0015] Preferably, the ratio of the inner diameter to the outer diameter of the second positive electrode is (9.6-11.4):(14.4-17.1), wherein the selection range of the inner diameter of the second positive electrode "9.6-11.4" can be, for example, 9.6, 9.8, 10, 10.2, 10.4, 10.6, 10.8, 11, 11.2 or 11.4, etc., and the selection range of the outer diameter of the second positive electrode "14.4-17.1" can be, for example, 14.4, 14.8, 15.2, 15.8, 16.2, 16.6, 17 or 17.1, etc.

[0016] Preferably, the thickness ratio of the negative electrode sheet to the first positive electrode sheet is (3-4):1, for example, it can be 3:1, 3.5:1 or 4:1, etc.

[0017] Preferably, the thickness ratio of the first positive electrode sheet to the second positive electrode sheet is (3-5):10, for example, it can be 3:10, 3.5:10, 4:10, 4.5:10 or 5:10, etc.

[0018] In this invention, if the thickness ratio of the first positive electrode sheet to the second positive electrode sheet is too large, that is, if the thickness of the second positive electrode sheet is too small, it cannot make close contact with the positive electrode shell, resulting in poor internal contact and excessively high internal resistance of the cell.

[0019] Preferably, the negative electrode sheet has a ring-shaped hollow structure.

[0020] In this invention, if the negative electrode sheet has a ring-shaped hollow structure, the positive and negative electrodes will have more comprehensive contact, which will enable the full theoretical capacity of the negative electrode to be utilized and ensure the pulse capability at the end of the discharge.

[0021] Preferably, the ratio of the inner diameter of the negative electrode to the outer diameter of the negative electrode is (2-5):(8-9.7), wherein the selection range of the inner diameter of the negative electrode "2-5" can be, for example, 2, 3, 4 or 5, and the selection range of the outer diameter of the negative electrode "8-9.7" can be, for example, 8, 8.2, 8.4, 8.6, 8.8, 9, 9.2, 9.4 or 9.7, etc.

[0022] In a second aspect, the present invention provides a method for preparing a lithium manganese battery cell as described in the first aspect, the method comprising the following steps:

[0023] A second positive electrode with a ring-shaped hollow structure is prepared using a mold of a corresponding shape;

[0024] The separator is placed on the surface of the negative electrode, and electrolyte is injected into the surface of the separator;

[0025] Place the second positive electrode on the surface of the separator in a direction away from the negative electrode;

[0026] The first positive electrode is placed on the surface of the second positive electrode along a direction away from the negative electrode to obtain the lithium manganese battery cell.

[0027] Preferably, the second positive electrode is a manganese dioxide positive electrode, and the preparation steps of the manganese dioxide positive electrode are as follows:

[0028] The manganese source, catalyst and solvent are mixed to obtain the manganese dioxide positive electrode, and the manganese dioxide positive electrode is made into a second positive electrode sheet with a ring hollow structure by using a mold of the corresponding shape.

[0029] Preferably, the manganese source includes manganese dioxide, the catalyst includes acetylene black, and the solvent includes polytetrafluoroethylene.

[0030] Preferably, the mixing process is accompanied by stirring.

[0031] Preferably, the diaphragm is a non-woven fabric diaphragm, and the material of the non-woven fabric diaphragm includes polypropylene and / or polyethylene.

[0032] Preferably, the electrolyte in step (2) includes any one or a combination of at least two of lithium perchlorate, propylene carbonate, or dimethoxyethane.

[0033] As a preferred technical solution, the preparation method includes the following steps:

[0034] (I) Mix and stir the manganese source, catalyst and solvent to obtain manganese dioxide positive electrode, and use a mold of corresponding shape to make the manganese dioxide positive electrode into a second positive electrode sheet with a ring hollow structure;

[0035] (II) The negative electrode sheet is made into a negative electrode sheet with a ring-shaped hollow structure using a mold of the corresponding shape;

[0036] (III) Place the diaphragm on the surface of the negative electrode and inject electrolyte into the diaphragm surface;

[0037] (IV) Place the second positive electrode on the surface of the separator in a direction away from the negative electrode;

[0038] (V) Place the first positive electrode on the surface of the second positive electrode along a direction away from the negative electrode to obtain the lithium manganese battery cell.

[0039] Thirdly, the present invention provides a lithium manganese dioxide battery, the lithium manganese dioxide battery comprising a positive electrode cap, a negative electrode cap, and a lithium manganese cell as described in the first aspect located between the positive electrode cap and the negative electrode cap.

[0040] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] (1) The present invention designs a novel lithium manganese cell structure, which can increase the internal space of the cell and increase the amount of internal electrolyte, and also improve the contact between the positive and negative electrodes at the end of the discharge, avoiding the problem of poor contact between the positive and negative electrodes at the end of the discharge due to the expansion of the positive electrode and the reduction of the negative electrode, so that the battery can achieve long-lasting and effective discharge.

[0043] (2) The lithium manganese battery prepared based on the lithium manganese cell structure designed in this invention has good performance when applied to high current and has good application prospects. Attached Figure Description

[0044] Figure 1 is a cross-sectional schematic diagram of the lithium manganese dioxide battery provided in Embodiment 1 of the present invention.

[0045] Among them, 1-negative electrode cover, 2-negative electrode sheet, 3-separator, 4-second positive electrode sheet, 5-first positive electrode sheet, 6-positive electrode cover, 7-lithium manganese cell. Detailed Implementation

[0046] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0047] Example 1

[0048] This embodiment provides a lithium manganese dioxide battery. A cross-sectional view of the lithium manganese dioxide battery is shown in Figure 1. The lithium manganese dioxide battery includes a positive electrode cover 6, a negative electrode cover 1, and a lithium manganese cell 7. The positive electrode cover 6 and the negative electrode cover 1 are interlocked to form a receiving cavity, and the lithium manganese cell 7 is located within the receiving cavity. The lithium manganese cell 7 includes a first positive electrode 5, a second positive electrode 4, a negative electrode 2, a separator 3, and an electrolyte. The separator 3 separates the negative electrode 2 from the first positive electrode 5, and also separates the negative electrode 2 from the second positive electrode 4.

[0049] The negative electrode 2, the separator 3, and the first positive electrode 5 are stacked in sequence. The second positive electrode 4 has a ring-shaped hollow structure. The second positive electrode 4 is sleeved on the outside of the first positive electrode 5 and the negative electrode 2. A first gap is left between the second positive electrode 4 and the first positive electrode 5, and a second gap is left between the negative electrode 2 and the first positive electrode 5.

[0050] The ratio of the diameter of the negative electrode 2, the inner diameter of the second positive electrode 4, and the diameter of the first positive electrode 5 is 9:10:9.5; the ratio of the inner diameter of the second positive electrode 4 to the outer diameter of the second positive electrode 4 is 10:15.5; the thickness ratio of the negative electrode 2 to the first positive electrode 5 is 3.5:1; and the thickness ratio of the first positive electrode 5 to the second positive electrode 4 is 10:4.

[0051] This embodiment also provides a method for preparing a lithium manganese battery cell 7, the method comprising the following steps:

[0052] (1) Manganese dioxide, acetylene black and polytetrafluoroethylene are mixed to obtain manganese dioxide positive electrode, and the manganese dioxide positive electrode is made into a second positive electrode sheet 4 with a ring hollow structure by using a mold of the corresponding shape;

[0053] (2) Place the non-woven membrane 3 made of polyethylene on the surface of the negative electrode 2, and inject the electrolyte dimethoxyethane on the surface of the membrane 3.

[0054] (3) Place the second positive electrode 4 on the surface of the diaphragm 3 in a direction away from the negative electrode 2;

[0055] (4) Place the first positive electrode 5 on the surface of the second positive electrode 4 along the direction away from the negative electrode 2 to obtain the lithium manganese battery cell 7.

[0056] Example 2

[0057] This embodiment provides a lithium manganese dioxide battery, which includes a positive electrode cover, a negative electrode cover, and a lithium manganese cell. The positive electrode cover and the negative electrode cover are interlocked to form a receiving cavity, and the lithium manganese cell is located within the receiving cavity. The lithium manganese cell includes a first positive electrode plate, a second positive electrode plate, a negative electrode plate, a separator, and an electrolyte. The separator separates the negative electrode plate from the first positive electrode plate and the negative electrode plate from the second positive electrode plate.

[0058] The negative electrode, the separator, and the first positive electrode are stacked in sequence. The second positive electrode has a ring-shaped hollow structure. The second positive electrode is sleeved on the outside of the first positive electrode and the negative electrode. A first gap is left between the second positive electrode and the first positive electrode, and a second gap is left between the negative electrode and the first positive electrode.

[0059] The ratio of the diameter of the negative electrode, the inner diameter of the second positive electrode, and the diameter of the first positive electrode is 8:9.6:8.8; the ratio of the inner diameter of the second positive electrode to the outer diameter of the second positive electrode is 9.6:14.4; the thickness ratio of the negative electrode to the first positive electrode is 3:1; and the thickness ratio of the first positive electrode to the second positive electrode is 10:3.

[0060] This embodiment also provides a method for preparing a lithium manganese battery cell, the method comprising the following steps:

[0061] (1) Manganese dioxide, acetylene black and polytetrafluoroethylene are mixed to obtain a manganese dioxide positive electrode. The manganese dioxide positive electrode is then made into a second positive electrode sheet with a ring-shaped hollow structure by using a mold of the corresponding shape.

[0062] (2) Place a non-woven membrane made of polyethylene on the surface of the negative electrode and inject propylene carbonate electrolyte into the surface of the membrane.

[0063] (3) Place the second positive electrode on the surface of the separator in a direction away from the negative electrode;

[0064] (4) Place the first positive electrode on the surface of the second positive electrode along the direction away from the negative electrode to obtain the lithium manganese battery cell.

[0065] Example 3

[0066] This embodiment provides a lithium manganese dioxide battery, which includes a positive electrode cover, a negative electrode cover, and a lithium manganese cell. The positive electrode cover and the negative electrode cover are interlocked to form a receiving cavity, and the lithium manganese cell is located within the receiving cavity. The lithium manganese cell includes a first positive electrode plate, a second positive electrode plate, a negative electrode plate, a separator, and an electrolyte. The separator separates the negative electrode plate from the first positive electrode plate and the negative electrode plate from the second positive electrode plate.

[0067] The negative electrode, the separator, and the first positive electrode are stacked in sequence. The second positive electrode has a ring-shaped hollow structure. The second positive electrode is sleeved on the outside of the first positive electrode and the negative electrode. A first gap is left between the second positive electrode and the first positive electrode, and a second gap is left between the negative electrode and the first positive electrode.

[0068] The ratio of the diameter of the negative electrode, the inner diameter of the second positive electrode, and the diameter of the first positive electrode is 9.7:11.4:10.45; the ratio of the inner diameter of the second positive electrode to the outer diameter of the second positive electrode is 11.4:17.1; the thickness ratio of the negative electrode to the first positive electrode is 4:1; and the thickness ratio of the first positive electrode to the second positive electrode is 10:5.

[0069] This embodiment also provides a method for preparing a lithium manganese battery cell, the method comprising the following steps:

[0070] (1) Manganese dioxide, acetylene black and polytetrafluoroethylene are mixed to obtain a manganese dioxide positive electrode. The manganese dioxide positive electrode is then made into a second positive electrode sheet with a ring-shaped hollow structure by using a mold of the corresponding shape.

[0071] (2) Place a non-woven polypropylene diaphragm on the surface of the negative electrode and inject lithium perchlorate electrolyte into the diaphragm surface.

[0072] (3) Place the second positive electrode on the surface of the separator in a direction away from the negative electrode;

[0073] (4) Place the first positive electrode on the surface of the second positive electrode along the direction away from the negative electrode to obtain the lithium manganese battery cell.

[0074] Example 4

[0075] The difference between this embodiment and Embodiment 1 is that the negative electrode sheet has a ring-shaped hollow structure, and the ratio of the inner diameter to the outer diameter of the negative electrode sheet is 3.5:9.

[0076] The remaining preparation methods and parameters are consistent with those in Example 1.

[0077] Example 5

[0078] The difference between this embodiment and embodiment 4 is that the ratio of the inner diameter of the negative electrode to the outer diameter of the negative electrode is 2:9.7.

[0079] The remaining preparation methods and parameters are consistent with those in Example 4.

[0080] Example 6

[0081] The difference between this embodiment and embodiment 4 is that the ratio of the inner diameter of the negative electrode to the outer diameter of the negative electrode is 5:8.

[0082] The remaining preparation methods and parameters are consistent with those in Example 4.

[0083] Example 7

[0084] The difference between this embodiment and Embodiment 1 is that the ratio of the diameter of the negative electrode to the inner diameter of the second positive electrode is 10:9.6.

[0085] The remaining preparation methods and parameters are consistent with those in Example 1.

[0086] Example 8

[0087] The difference between this embodiment and Embodiment 1 is that the ratio of the diameter of the negative electrode to the inner diameter of the second positive electrode is 8:12.

[0088] The remaining preparation methods and parameters are consistent with those in Example 1.

[0089] Example 9

[0090] The difference between this embodiment and Embodiment 1 is that the ratio of the inner diameter of the second positive electrode to the diameter of the first positive electrode is 12:8.8.

[0091] The remaining preparation methods and parameters are consistent with those in Example 1.

[0092] Example 10

[0093] The difference between this embodiment and Embodiment 1 is that the ratio of the inner diameter of the second positive electrode to the diameter of the first positive electrode is 9:10.45.

[0094] The remaining preparation methods and parameters are consistent with those in Example 1.

[0095] Example 11

[0096] The difference between this embodiment and Embodiment 1 is that the thickness ratio of the first positive electrode sheet to the second positive electrode sheet is 7:10.

[0097] The remaining preparation methods and parameters are consistent with those in Example 1.

[0098] Comparative Example 1

[0099] The difference between this comparative example and Example 1 is that the lithium manganese battery cell does not include a second positive electrode sheet with a ring-shaped hollow structure.

[0100] The remaining preparation methods and parameters are consistent with those in Example 1.

[0101] Comparative Example 2

[0102] The difference between this comparative example and Example 1 is that the lithium manganese cell does not include a first positive electrode plate.

[0103] The remaining preparation methods and parameters are consistent with those in Example 1.

[0104] Comparative Example 3

[0105] The difference between this comparative example and Example 1 is that there is no gap between the second positive electrode and the first positive electrode, that is, the inner diameter of the second positive electrode is equal to the diameter of the first positive electrode.

[0106] The remaining preparation methods and parameters are consistent with those in Example 1.

[0107] Comparative Example 4

[0108] The difference between this comparative example and Example 1 is that there is no gap between the negative electrode and the second positive electrode, that is, the diameter of the negative electrode is equal to the inner diameter of the second positive electrode.

[0109] The remaining preparation methods and parameters are consistent with those in Example 1.

[0110] Performance testing

[0111] The electrochemical performance of the lithium manganese dioxide batteries prepared in Examples 1-11 and Comparative Examples 1-4 was tested.

[0112] Test conditions: ambient temperature 20±3℃.

[0113] The test results are shown in Table 1.

[0114] Table 1

[0115]

[0116]

[0117] analyze:

[0118] As shown in the table above, the novel lithium-manganese battery cell structure designed in this invention can not only increase the internal space of the cell and the amount of internal electrolyte, thus improving the cell's capacity utilization, but also improve the contact between the positive and negative electrodes at the end of discharge, enhancing the high-current pulse capability. This avoids the poor contact problem caused by the expansion of the positive electrode and the reduction of the negative electrode at the end of discharge, enabling the battery to achieve sustained and effective discharge. The lithium-manganese dioxide battery prepared with this structure can release higher capacity within the same external dimensions, making it competitive in the market. It is also suitable for high-current pulse discharge, has a wider application market, and shows good application prospects.

[0119] A comparison of the data results from Example 1 and Example 4 shows that if the structure of the negative electrode is also a ring-shaped hollow structure, the positive and negative electrode contact effect is the best and the discharge performance is optimal.

[0120] A comparison of the data results from Examples 1 and 7-8 shows that if the ratio of the diameter of the negative electrode to the inner diameter of the second positive electrode is too small, i.e., the diameter of the negative electrode is too small, the gap between the two will be too large, resulting in low voltage and poor capacity performance; if the ratio of the diameter of the negative electrode to the inner diameter of the second positive electrode is too large, the gap between the two will be too small, resulting in incomplete contact between the positive and negative electrodes.

[0121] A comparison of the data results from Examples 1 and 9-10 shows that if the ratio of the inner diameter of the second positive electrode to the diameter of the first positive electrode is too large, i.e., the diameter of the first positive electrode is too small, the gap between the two will be too large, causing the positive electrode to be misaligned and the reaction to be incomplete. If the ratio of the inner diameter of the second positive electrode to the diameter of the first positive electrode is too small, i.e., the diameter of the first positive electrode is too large, the gap between the two will be too small, resulting in powder shedding and low voltage, which is not conducive to the absorption of electrolyte.

[0122] A comparison of the data results from Example 1 and Example 11 shows that if the thickness ratio of the first positive electrode to the second positive electrode is too large, that is, if the thickness of the second positive electrode is too small, there will be poor contact, high internal resistance, and poor capacity performance.

[0123] A comparison of the data results from Example 1 and Comparative Example 1 shows that if the lithium manganese battery cell does not include a second positive electrode with a ring-shaped hollow structure, the capacity will be lower and the pulse capability will be poorer.

[0124] A comparison of the data results from Example 1 and Comparative Example 2 shows that if the first positive electrode is not included in the lithium manganese battery cell, the capacity will be significantly reduced and the pulse will be poor.

[0125] A comparison of the data results from Example 1 and Comparative Examples 3-4 shows that if there is no gap between the second positive electrode and the first positive electrode, or no gap between the negative electrode and the second positive electrode, the capacity will show a decreasing trend and the pulse performance will be significantly reduced.

[0126] The applicant declares that the present invention is illustrated by the above embodiments, but the present invention is not limited to the above process steps, that is, it does not mean that the present invention must rely on the above process steps to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions of the raw materials used in the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A lithium manganese battery cell, characterized in that, The lithium manganese battery cell includes a first positive electrode, a second positive electrode, a negative electrode, a separator, and an electrolyte. The separator separates the negative electrode from the first positive electrode and the negative electrode from the second positive electrode. The negative electrode, the separator, and the first positive electrode are stacked in sequence. The second positive electrode has an annular hollow structure and is sleeved on the outside of the first positive electrode and the negative electrode. A first gap is left between the second positive electrode and the first positive electrode, and a second gap is left between the negative electrode and the second positive electrode.

2. The lithium manganese battery cell according to claim 1, characterized in that, The ratio of the diameter of the negative electrode, the inner diameter of the second positive electrode, and the diameter of the first positive electrode is (8-9.7):(9.6-11.4):(8.8-10.45).

3. The lithium manganese battery cell according to claim 1, characterized in that, The ratio of the inner diameter to the outer diameter of the second positive electrode is (9.6-11.4):(14.4-17.1).

4. The lithium manganese battery cell according to claim 1, characterized in that, The thickness ratio of the negative electrode to the first positive electrode is (3-4):

1.

5. The lithium manganese battery cell according to claim 1, characterized in that, The thickness ratio of the first positive electrode sheet to the second positive electrode sheet is (3-5):

10.

6. The lithium manganese battery cell according to claim 1, characterized in that, The negative electrode has a ring-shaped hollow structure.

7. The lithium manganese battery cell according to claim 6, characterized in that, The ratio of the inner diameter to the outer diameter of the negative electrode is (2-5):(8-9.7).

8. A method for preparing a lithium manganese battery cell, characterized in that, The preparation method is used to prepare a lithium manganese battery cell as described in any one of claims 1-7. The preparation method includes the following steps: preparing a second positive electrode sheet with a ring-shaped hollow structure using a mold of a corresponding shape; placing a separator on the surface of a negative electrode sheet and injecting an electrolyte onto the surface of the separator; placing the second positive electrode sheet on the surface of the separator along a direction away from the negative electrode sheet; placing a first positive electrode sheet on the surface of the second positive electrode sheet along a direction away from the negative electrode sheet to obtain the lithium manganese battery cell.

9. The preparation method according to claim 8, characterized in that, The preparation method includes the following steps: (I) mixing and stirring a manganese source, acetylene black and a solvent to obtain a manganese dioxide positive electrode, and forming a second positive electrode sheet with a ring-shaped hollow structure using a mold of the corresponding shape; (II) forming a negative electrode sheet with a ring-shaped hollow structure using a mold of the corresponding shape; (III) placing a separator on the surface of the negative electrode sheet and injecting an electrolyte onto the surface of the separator; (IV) placing the second positive electrode sheet on the surface of the separator along a direction away from the negative electrode sheet; (V) placing a first positive electrode sheet on the surface of the second positive electrode sheet along a direction away from the negative electrode sheet to obtain the lithium manganese battery cell.

10. A lithium manganese dioxide battery, characterized in that, The lithium manganese dioxide battery includes a positive electrode cover, a negative electrode cover, and a lithium manganese battery cell as described in any one of claims 1-7. The positive electrode cover and the negative electrode cover are fastened together to form a receiving cavity, and the lithium manganese battery cell is located in the receiving cavity.

Images