Multi-tab lithium-manganese battery

Abstract

The utility model relates to battery technology field especially relates to a kind of multi-tab lithium-manganese battery, including electric core, shell and cover group.Electric core is formed by the winding of the positive sheet, diaphragm and negative sheet of laminated arrangement, and the positive sheet has the coating area of coating positive material and the blank area of not coating positive material, and the blank area is cut to form multiple positive tabs, and the negative sheet includes copper foil and lithium ribbon compounded on copper foil, and the area of copper foil not compounded lithium ribbon forms the negative full tab of electric core.Shell only one end has opening, and electric core is placed in shell through opening, and negative full tab is electrically connected with shell, and cover group cover is arranged at opening, and positive tab is electrically connected with cover group.The multi-tab lithium-manganese battery can solve the problems of existing lithium-manganese battery in high-current discharge, safety and production process, etc., and improve the product performance and production efficiency of lithium-manganese battery.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, and in particular to a multi-tab lithium manganese battery. Background Technology

[0002] With the continuous development of technology, various electronic devices are placing increasingly higher demands on battery performance. Lithium-manganese batteries, due to their high energy density and excellent discharge performance, have been widely used in numerous fields. However, traditional lithium-manganese batteries still have some shortcomings in areas such as high-current discharge, safety, and manufacturing processes. For example, the conventional single-tab design results in uneven current distribution during high-current discharge, leading to severe battery heating and reduced discharge efficiency. Furthermore, traditional electrode manufacturing processes need improvement in ensuring electrode performance consistency and production efficiency.

[0003] Therefore, there is an urgent need to design a multi-tab lithium manganese battery to solve the above technical problems. Utility Model Content

[0004] The purpose of this invention is to propose a multi-tab lithium manganese battery to solve the problems of existing lithium manganese batteries in terms of high-current discharge, safety and production process, and to improve the product performance and production efficiency of lithium manganese batteries.

[0005] To achieve this objective, the present invention adopts the following technical solution:

[0006] A multi-tab lithium manganese battery is provided, comprising:

[0007] A battery cell is formed by winding together a positive electrode sheet, a separator, and a negative electrode sheet stacked on top of each other. The positive electrode sheet has a coated area coated with positive electrode material and a blank area uncoated with positive electrode material. The blank area is cut to form multiple positive electrode tabs. The negative electrode sheet includes a copper foil and a lithium strip laminated on the copper foil. The area of ​​the copper foil uncoated with the lithium strip forms the negative electrode tab of the battery cell.

[0008] The housing has an opening at only one end, through which the battery cell is placed inside the housing, and the negative electrode tab is electrically connected to the housing.

[0009] A cover assembly is provided at the opening, and the positive electrode tab is electrically connected to the cover assembly.

[0010] Optionally, in the length direction of the copper foil, the length of the lithium strip is the same as the length of the copper foil, and in the width direction of the copper foil, the first side of the lithium strip is flush with the first side of the copper foil, and the second side of the lithium strip is spaced from the second side of the copper foil.

[0011] Optionally, the multi-tab lithium manganese battery includes an upper connector, which is disposed at the positive electrode of the cell, and the positive electrode tab is electrically connected to the cover assembly through the upper connector.

[0012] Optionally, multiple positive electrode tabs, the upper connector, and the cover assembly are welded together.

[0013] Optionally, the multi-tab lithium manganese battery includes a lower connector, which is disposed at the negative electrode of the cell, and the negative electrode tabs are electrically connected to the casing through the lower connector.

[0014] Optionally, the negative electrode tab, the lower connector, and the bottom of the housing are welded together.

[0015] Optionally, the positive electrode, the separator, and the negative electrode are stacked and wound to form the battery cell, the blank area exposes the separator at one end of the axial direction of the battery cell, and the copper foil exposes the separator at the other end of the axial direction of the battery cell;

[0016] Along the axial direction of the battery cell, the width of the coated area is a1, the width of the blank area is a2, the width of the copper foil is b1, the width of the lithium strip is b2, and the width of the separator is c, where c > a1 + a2, c > b1, and a1 > b2.

[0017] Optionally, the width of the blank area is a2, where 6mm > a2 > 3mm;

[0018] And / or, the width of the copper foil is b1, the width of the lithium strip is b2, and 6mm > b1 - b2 > 3mm.

[0019] Optionally, the positive electrode sheet includes an aluminum foil on which the positive electrode material is coated to form the coating area.

[0020] Optionally, the cover assembly includes a top cap, a PTC, an explosion-proof gasket, an explosion-proof aluminum-plastic film, an explosion-proof cover fastener, and an insulating component. The circumferential edge of the explosion-proof cover fastener is folded over to fix the explosion-proof gasket and the explosion-proof aluminum-plastic film to form an explosion-proof component. The PTC is sandwiched between the top cap and the explosion-proof component, and the insulating component is sleeved on the outer periphery of the top cap and the explosion-proof component.

[0021] The beneficial effects of this utility model include at least the following:

[0022] This invention provides a multi-tab lithium-manganese battery, comprising a cell, a casing, and a cover assembly. The cell is formed by winding together a positive electrode sheet, a separator, and a negative electrode sheet stacked on top of each other. The positive electrode sheet has a coated area with positive electrode material and a blank area without positive electrode material. The blank area is cut to form multiple positive tabs. The negative electrode sheet includes a copper foil and a lithium strip laminated on the copper foil. The area of ​​the copper foil without the lithium strip laminated forms the negative electrode tab of the cell. The casing has an opening at only one end, through which the cell is placed inside the casing. The negative electrode tab is electrically connected to the casing. The cover assembly covers the opening of the casing, and the positive tab is electrically connected to the cover assembly. By cutting multiple positive tabs in the blank area of ​​the positive electrode sheet, the multi-tab design of the positive electrode makes the current distribution on the positive electrode sheet more uniform, avoiding the problem of insufficient capacity caused by excessive discharge current during battery discharge, which prevents the positive electrode from being fully utilized. This significantly improves the high-current discharge performance of the battery. The negative electrode uses a copper foil-lithium metal composite strip, which combines the good conductivity of copper foil with the high specific capacity of lithium metal. This not only improves the energy density of the battery, but also improves the high-current discharge performance of the battery to a certain extent. At the same time, the use of the copper foil-lithium metal composite strip simplifies the traditional manufacturing process of coating negative electrode materials on copper foil to form a negative electrode sheet, thus improving production efficiency. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of the multi-tab lithium manganese battery provided in this embodiment of the utility model;

[0024] Figure 2 This is a schematic diagram of the negative electrode sheet provided in this embodiment of the utility model;

[0025] Figure 3 This is a schematic diagram of the structure of the positive electrode sheet provided in this embodiment of the utility model.

[0026] Figure Labels

[0027] 1. Battery cell; 11. Positive electrode sheet; 111. Aluminum foil; 112. Positive electrode material; 12. Negative electrode sheet; 121. Copper foil; 122. Lithium strip; 13. Separator; 2. Housing; 3. Cover assembly; 31. Explosion-proof cover fastener; 32. PTC; 33. Top cap; 34. Explosion-proof gasket; 35. Explosion-proof aluminum-plastic film; 36. Insulating component; 4. Upper connector; 5. Lower connector. Detailed Implementation

[0028] To make the technical problem solved by this utility model, the technical solution adopted, and the technical effect achieved clearer, the technical solution of this utility model will be further described below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely for explaining this utility model and not for limiting it. Furthermore, it should be noted that, for ease of description, only the parts related to this utility model are shown in the accompanying drawings, not all of them.

[0029] In the description of this utility model, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0030] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0031] In the description of this embodiment, the terms "upper," "lower," "left," and "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. In addition, the terms "first" and "second" are only used for distinction in description and have no special meaning.

[0032] The technical solution of this utility model will be further described below with reference to the accompanying drawings and specific embodiments.

[0033] like Figures 1 to 3As shown, this embodiment discloses a multi-tab lithium manganese battery, including a cell 1, a casing 2, and a cover assembly 3. The cell 1 is formed by winding a positive electrode sheet 11, a separator 13, and a negative electrode sheet 12 stacked together. The positive electrode sheet 11 has a coated area coated with positive electrode material 112 and a blank area uncoated with positive electrode material 112. The blank area is cut to form multiple positive tabs. The negative electrode sheet 12 includes a copper foil 121 and a lithium strip 122 laminated on the copper foil 121. The area of ​​the copper foil 121 without the lithium strip 122 laminated forms the negative full tab of the cell 1. The casing 2 has an opening at only one end, through which the cell 1 is placed inside the casing 2. The negative full tab is electrically connected to the casing 2. The cover assembly 3 covers the opening of the casing 2, and the positive tab is electrically connected to the cover assembly 3. The battery cell 1 forms multiple positive tabs by cutting into the blank area of ​​the positive electrode sheet 11. The multi-tab design of the positive electrode makes the current distribution on the positive electrode sheet 11 more uniform, avoiding the problem of insufficient capacity caused by the positive electrode not being fully utilized due to excessive discharge current during the discharge process, thereby significantly improving the high-current discharge performance of the battery. The negative electrode sheet 12 uses a copper foil-lithium metal composite strip. This composite strip combines the good conductivity of copper foil 121 and the high specific capacity characteristics of lithium metal. It can not only improve the energy density of the battery, but also improve the high-current discharge performance of the battery to a certain extent. At the same time, the use of copper foil-lithium metal composite strip simplifies the traditional manufacturing process of coating negative electrode material on copper foil 121 to form negative electrode sheet 12, improving production efficiency.

[0034] In this embodiment, the positive electrode 11, the separator 13, and the negative electrode 12 are stacked and wound to form the battery cell 1. A blank area exposes the separator 13 at one end of the axial direction of the battery cell 1, while the copper foil 121 exposes the separator 13 at the other end of the axial direction of the battery cell 1. This ensures the connection between the positive electrode tab and the cover assembly 3, and the connection between the negative electrode tab and the housing 2. The separator 13 includes a first separator and a second separator, and the first separator, the positive electrode 11, the second separator, and the negative electrode 12 are stacked.

[0035] In this embodiment, as Figure 2 and Figure 3As shown, along the axial direction of cell 1, the width of the coated area is a1, the width of the blank area is a2, the width of the copper foil 121 is b1, the width of the lithium strip 122 is b2, and the width of the separator 13 is c, where c > a1 + a2, c > b1, and a1 > b2. When the positive electrode 11 and the negative electrode 12 are stacked, the coated area of ​​the positive electrode 11 corresponds to the position of the lithium strip 122, while the blank area extends beyond the lithium strip 122 to prevent the positive electrode tab from contacting the negative electrode 12. Furthermore, the area on the copper foil 121 where the lithium strip 122 is not composite extends beyond the coated area to prevent the negative electrode tab from contacting the positive electrode 11. The width of the separator 13 is greater than the width of both the positive electrode 11 and the negative electrode 12 to ensure that the separator 13 can completely separate the positive electrode 11 and the negative electrode 12. In addition, a1 > b2, so that the width of the lithium strip 122 in the axial direction of the cell 1 does not exceed the width of the coating area of ​​the positive electrode 11, thereby preventing the lithium strip 122 from piercing the separator 13 and coming into contact with the positive electrode tab, causing a short circuit in the cell 1.

[0036] In this embodiment, as Figure 2 As shown, along the length of the copper foil 121, the length of the lithium strip 122 is the same as that of the copper foil 121. Along the width of the copper foil 121, the first side of the lithium strip 122 is flush with the first side of the copper foil 121, and the second side of the lithium strip 122 is spaced from the second side of the copper foil 121. Both the copper foil 121 and the lithium strip 122 adopt a rectangular structure, with one long side (i.e., the first side) of the rectangular structure flush with the first side. This creates an area on the other long side of the copper foil 121 where the lithium strip 122 is not composited. This area serves as the negative electrode tab of the battery cell 1. The copper foil 121 acts as a current collector, efficiently collecting and conducting electrons, while metallic lithium acts as the active material, providing a strong electrochemical driving force for the battery. During battery discharge, metallic lithium is uniformly deposited and dissolved on the surface of the copper foil 121, effectively reducing the polarization of the negative electrode and improving the battery's discharge efficiency. In a specific implementation, the thickness of the copper foil 121 can be 0.02 mm in the thickness direction, while the thickness of the negative electrode 12 formed by the lithium strip 122 composited on the copper foil 121 is 0.14 mm.

[0037] Optionally, the width of the copper foil 121 is b1, and the width of the lithium strip 122 is b2, where 6mm > b1 - b2 > 3mm. In this embodiment, the width of the lithium strip 122 is 23mm, and the width of the copper foil 121 can be 28mm, thereby forming a positive electrode tab with an axial length of 5mm in the cell 1.

[0038] Optionally, the width of the blank area is a2, where 6mm > a2 > 3mm. In this embodiment, the width of the coated area is 24mm, and the positive electrode 11 can be made of aluminum foil 111 with a width of 29mm.

[0039] Optionally, such as Figure 3As shown, the positive electrode 11 includes an aluminum foil 111, on which a positive electrode material 112 is coated to form a coating area. The positive electrode material 112 is composed of a mixture of manganese dioxide, conductive carbon black, Ketjen black, carbon nanotubes, graphite, and tetrafluoroethylene.

[0040] In this embodiment, the positive electrode material 112 is mixed uniformly according to the following mass ratio: manganese dioxide: conductive carbon black: Ketjen black: carbon nanotubes: graphite: PTFE = 90.5: 2.8: 0.5: 0.5: 1.2: 4.5. Then, using a continuous coating equipment, the mixed positive electrode material 112 is uniformly coated onto the surface of aluminum foil 111. During the coating process, the exposed sides of the aluminum foil 111 are controlled to be 5mm-10mm. After coating, the material is rolled on a rolling mill at a pressure of 120T-160T, with the rolling thickness controlled at 0.18mm-0.40mm. The rolled positive electrode is then slit into the required positive electrode size using a slitting knife. The total length of the positive electrode sheet 11 is controlled to be 260±1mm, and the width is controlled to be 24±0.5mm, with the exposed width of the aluminum foil 111, i.e., the blank area, controlled to be 5±0.5mm. After slitting, the positive electrode 11 is first dried in a forced-air dryer at 180℃ for 8 hours, and then vacuum dried at 190±10℃ for 15 hours to remove moisture and organic solvents and improve the performance of the positive electrode 11.

[0041] The prepared positive electrode 11 and negative electrode 12 are wound with the separator 13 to form the battery cell 1. During the stacking and winding process, the alignment accuracy between the positive electrode 11, negative electrode 12 and separator 13 must be ensured to avoid misalignment. The width of the separator 13 is 30±0.5mm to fully isolate the positive and negative electrodes and avoid short circuits.

[0042] Furthermore, such as Figure 1 As shown, the multi-tab lithium manganese battery includes an upper connector 4, which is disposed at the positive electrode of the cell 1. The positive tabs are electrically connected to the cover assembly 3 via the upper connector 4. In this embodiment, there are multiple positive tabs. By adding the upper connector 4 between the positive tabs and the cover assembly 3, it is unnecessary to align the multiple positive tabs before welding them to the cover assembly 3, thus improving welding efficiency. The upper connector 4 can be formed of a metal wire, metal strip, or metal sheet. The material of the upper connector 4 can be aluminum.

[0043] In this embodiment, multiple positive electrode tabs, upper connector 4, and cover assembly 3 are welded together. The positive electrode tabs and upper connector 4 can be welded using any suitable welding method among resistance welding, ultrasonic welding, and laser welding. The upper connector 4 and cover assembly 3 can also be welded using any suitable welding method among resistance welding, ultrasonic welding, and laser welding.

[0044] Optionally, such as Figure 1As shown, the multi-tab lithium manganese battery includes a lower connector 5, which is disposed at the negative electrode of the cell 1. The negative electrode tab is electrically connected to the casing 2 through the lower connector 5. In this embodiment, by adding a lower connector 5 between the negative electrode tab and the casing 2, the lower connector 5 can be connected to the negative electrode tab first, and then connected to the casing 2, thereby improving welding efficiency. The lower connector 5 can be formed of metal wire, metal strip, or metal sheet. The material of the lower connector 5 can be copper or copper-nickel composite material.

[0045] In this embodiment, the negative electrode tab, the lower connector 5, and the bottom of the housing 2 are welded together. The negative electrode tab and the lower connector 5 can be welded using any suitable welding method among resistance welding, ultrasonic welding, and laser welding. The lower connector 5 and the bottom of the housing 2 can also be welded using any suitable welding method among resistance welding, ultrasonic welding, and laser welding.

[0046] In practice, the upper connector 4 and the lower connector 5 can be selected for installation or installed simultaneously. After the upper connector 4 and / or the lower connector 5 are assembled with the core, they can be placed inside the housing 2. Then, the lower connector 5 or the negative electrode tab is welded to the bottom of the housing 2. After that, electrolyte is injected, and the cover assembly 3 is placed at the opening of the housing 2. Then, the upper connector 4 or the positive electrode tab is welded to the cover assembly 3. The electrolyte is prepared according to a certain ratio. The electrolyte formula is a LiClO4 molar concentration of 0.65 mol / L and a solvent ratio of PC (propylene carbonate): DME (ethylene glycol dimethyl ether): DOL (1,3-dioxolane) = 4:3:3. After the electrolyte is injected, the cover assembly 3 is placed at the opening of the housing 2 to form a semi-sealed battery casing. This ensures that the battery casing has a certain degree of sealing while allowing for the controlled release of internal gas pressure. After sealing, the battery is preliminarily tested to ensure that the battery's sealing and appearance quality meet the requirements.

[0047] The assembled battery is pre-discharged and discharged under a constant current of 600mA for 6 minutes to form a stable SEI film on the electrode material inside the battery, while removing some impurities and water of crystallization, thereby improving the performance and stability of the battery.

[0048] Battery performance testing equipment was used to test various performance indicators of the battery provided in this embodiment, including discharge performance and capacity retention. During the testing process, different usage environments (different temperatures) were simulated to comprehensively evaluate the battery's performance. Specific testing steps included:

[0049] (1) At room temperature 23±2℃, discharge at 2A to 2.0V;

[0050] (2) After being stored at a high temperature of 70℃ for 70 days, it is discharged to 2.0V at a normal temperature of 23±2℃ using 2A.

[0051] (3) Discharge from 2A to 2.0V under low temperature conditions of -20℃.

[0052] The test results are as follows:

[0053]

[0054] The multi-tab lithium manganese battery prepared through the above specific embodiments has been tested and verified to have achieved significant improvements in discharge rate, safety and production process, thus achieving the expected invention objectives.

[0055] Optionally, such as Figure 1 As shown, the cover assembly 3 includes a top cap 33, a PTC 32, an explosion-proof gasket 34, an explosion-proof aluminum-plastic film 35, an explosion-proof cover fastener 31, and an insulating component 36. The circumferential edge of the explosion-proof cover fastener 31 is folded over to fix the explosion-proof gasket 34 and the explosion-proof aluminum-plastic film 35 to form an explosion-proof component. The PTC 32 is sandwiched between the top cap 33 and the explosion-proof component, and the insulating component 36 is fitted around the outer periphery of the top cap 33 and the explosion-proof component. This cover assembly 3 gives the multi-tab lithium manganese battery provided in this embodiment a semi-sealed structure, which can effectively release the gas generated inside the battery during discharge, avoiding safety problems such as battery bulging and explosion caused by excessive internal pressure. At the same time, the reasonable selection of electrode materials and structural design also reduces the risk of internal short circuits in the battery, further improving the safety of the battery.

[0056] The above embodiments merely illustrate the basic principles and characteristics of this utility model. This utility model is not limited to the above embodiments. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed utility model. The scope of protection of this utility model is defined by the appended claims and their equivalents.

Claims

1. A multi-tab lithium manganese battery, characterized in that, include: The battery cell (1) is formed by winding a positive electrode sheet (11), a separator (13) and a negative electrode sheet (12) stacked together. The positive electrode sheet (11) has a coated area coated with positive electrode material (112) and a blank area uncoated with positive electrode material (112). The blank area is cut to form multiple positive electrode tabs. The negative electrode sheet (12) includes a copper foil (121) and a lithium strip (122) laminated on the copper foil (121). The area of ​​the copper foil (121) unlaminated with the lithium strip (122) forms the negative electrode tab of the battery cell (1). The housing (2) has an opening at only one end, and the battery cell (1) is placed inside the housing (2) through the opening. The negative electrode tab is electrically connected to the housing (2). The cover assembly (3) is placed over the opening, and the positive electrode tab is electrically connected to the cover assembly (3).

2. The multi-tab lithium manganese battery according to claim 1, characterized in that, In the length direction of the copper foil (121), the length of the lithium strip (122) is the same as the length of the copper foil (121). In the width direction of the copper foil (121), the first side of the lithium strip (122) is flush with the first side of the copper foil (121), and the second side of the lithium strip (122) is spaced from the second side of the copper foil (121).

3. The multi-tab lithium manganese battery according to claim 1, characterized in that, The multi-tab lithium manganese battery includes an upper connector (4), which is disposed on the positive electrode of the cell (1), and the positive electrode tab is electrically connected to the cover assembly (3) through the upper connector (4).

4. The multi-tab lithium manganese battery according to claim 3, characterized in that, The plurality of the positive electrode tabs, the upper connector (4) and the cover assembly (3) are welded together.

5. The multi-tab lithium manganese battery according to claim 1, characterized in that, The multi-tab lithium manganese battery includes a lower connector (5), which is disposed on the negative electrode of the cell (1). The negative electrode tab is electrically connected to the casing (2) through the lower connector (5).

6. The multi-tab lithium manganese battery according to claim 5, characterized in that, The negative electrode tab, the lower connector (5), and the bottom of the housing (2) are welded together.

7. The multi-tab lithium manganese battery according to claim 1, characterized in that, The positive electrode (11), the separator (13) and the negative electrode (12) are stacked and wound to form the battery cell (1). The blank area exposes the separator (13) at one end of the axial direction of the battery cell (1), and the copper foil (121) exposes the separator (13) at the other end of the axial direction of the battery cell (1). In the axial direction of the cell (1), the width of the coating area is a1, the width of the blank area is a2, the width of the copper foil (121) is b1, the width of the lithium strip (122) is b2, and the width of the separator (13) is c, where c > a1 + a2, c > b1, and a1 > b2.

8. The multi-tab lithium manganese battery according to claim 7, characterized in that, The width of the blank area is a2, where 6mm > a2 > 3mm; And / or, the width of the copper foil (121) is b1, the width of the lithium strip (122) is b2, and 6mm > b1 - b2 > 3mm.

9. The multi-tab lithium manganese battery according to claim 1, characterized in that, The positive electrode (11) includes an aluminum foil (111) on which the positive electrode material (112) is coated to form the coating area.

10. The multi-tab lithium manganese battery according to claim 1, characterized in that, The cover assembly (3) includes a top cap (33), a PTC (32), an explosion-proof gasket (34), an explosion-proof aluminum-plastic film (35), an explosion-proof cover fastener (31), and an insulating component (36). The circumferential edge of the explosion-proof cover fastener (31) is folded over to fix the explosion-proof gasket (34) and the explosion-proof aluminum-plastic film (35) to form an explosion-proof component. The PTC (32) is sandwiched between the top cap (33) and the explosion-proof component. The insulating component (36) is fitted around the top cap (33) and the outer periphery of the explosion-proof component.

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