Stacked core assembly, lithium battery and assembly method of stacked core assembly

Abstract

The application provides a laminated core assembly, a lithium battery and an assembling method of the laminated core assembly. The laminated core assembly comprises: a laminated core unit comprising a laminated core, the laminated core comprising a plurality of first single cells and a plurality of second single cells, the plurality of first single cells and the plurality of second single cells being arranged one by one in correspondence, a first negative tab being electrically connected with a corresponding second negative tab, and a first positive tab being electrically connected with a corresponding second positive tab; a positive current guide and a negative current guide, the external connection positive tabs of the plurality of first single cells being all bent and attached on one side of the positive current guide away from the first cell body, and the external connection negative tabs of the plurality of second single cells being all bent and attached on one side of the negative current guide away from the second cell body, so that the plurality of first single cells and the plurality of second single cells are arranged in parallel. The technical scheme of the application solves the problems of the existing laminated core assembly, such as the tearing of the outer layer tab, the virtual welding of the inner layer tab and the easy insertion of the tab into the cell.

Description

Technical Field

[0001] This invention relates to the field of lithium-ion battery technology, and more specifically, to a stacked core assembly, a lithium battery, and a method for assembling the stacked core assembly. Background Technology

[0002] Currently, in order to pursue higher single-cell capacity, lithium batteries often adopt a multi-cell parallel process route inside a single battery: First, two single cells are paired, and then the corresponding positive and negative tabs of the two are joined together and ultrasonically welded together to obtain paired dual cells. Then, the positive and negative tabs of the two sets of paired dual cells are ultrasonically welded together with the positive and negative connectors, respectively. Finally, the above connecting pieces are welded onto the cover plate assembly. After the two sets of paired dual cells are combined, bundled, covered with insulating film, inserted into the shell, and the cover plate is laser welded to the shell opening, the parallel assembly of four cells is completed.

[0003] However, the above solution has the following drawbacks: 1. After the two single cells are paired, the number of layers of tabs increases and the overall thickness of the tabs increases. When the welded tabs are ultrasonically welded together with the positive / negative connectors, the outer tabs are prone to tearing and the inner tabs are prone to poor soldering. This is because the high-frequency vibration energy of the ultrasonic waves cannot be evenly transmitted to all interfaces, causing stress to concentrate on the outer tabs, which eventually tear due to excessive fatigue and stretching. The inner tabs, due to energy attenuation, cannot generate enough heat to achieve interlayer bonding, thus leading to poor soldering. 2. In order to achieve the core-combining action of the two sets of paired dual cells, long tabs are required. After core-combining, the multi-layer tabs present an "S" shaped bend, and the tabs are very easy to insert into the inside of the cells, causing a short circuit risk.

[0004] To address the shortcomings of existing assembly structures, this invention proposes a stacked core assembly designed to solve the aforementioned problems. Summary of the Invention

[0005] The main objective of this invention is to provide a stacked core assembly, a lithium battery, and an assembly method for the stacked core assembly, in order to solve the problems in the prior art where the outer tabs are easily torn, the inner tabs are poorly soldered, and the tabs are easily inserted into the battery cell.

[0006] To achieve the above objectives, the present invention provides a stacked core assembly, comprising: a stacked core unit including a stacked core, the stacked core including a plurality of first single cells and a plurality of second single cells stacked along the thickness direction of the stacked core, wherein the plurality of first single cells and the plurality of second single cells are arranged in a one-to-one correspondence, the first single cell including a first cell body, a first positive electrode, a first negative electrode, and an external positive electrode, and the second single cell including a second cell body, a second positive electrode, a second negative electrode, and an external negative electrode, wherein the first negative electrode is electrically connected to the corresponding second negative electrode. The first positive electrode tab is electrically connected to the corresponding second positive electrode tab; the positive electrode guide and the negative electrode guide are located between the two sides of the stacked core unit in the thickness direction, the positive electrode guide is located between the two sides of the stacked core unit in the thickness direction, the external positive electrode tabs of multiple first single cells are bent and attached to the side of the positive electrode guide away from the first cell body, and the external negative electrode tabs of multiple second single cells are bent and attached to the side of the negative electrode guide away from the second cell body, so that multiple first single cells and multiple second single cells are arranged in parallel.

[0007] In the above technical solution, on the one hand, by pairing the first single cell with the second single cell and completing the interconnection of the electrodes inside the cell (i.e., directly welding the first positive electrode to the second positive electrode and the first negative electrode to the second negative electrode), and using additional external positive and negative electrodes, with the external positive electrode bent and attached to the side of the positive electrode guide that is away from the first cell body, and the external negative electrode bent and attached to the side of the negative electrode guide that is away from the second cell body, this not only reduces the number of times the same electrode is welded, but also reduces the thickness of the welding interface by welding the external positive electrode only to the positive electrode guide and the external negative electrode only to the negative electrode guide, allowing the laser or ultrasonic welding energy to be evenly transmitted to each contact surface, thereby eliminating defects such as outer electrode tearing and inner layer poor soldering. This significantly improves the reliability and yield of electrical connections, thus solving the problem of uneven ultrasonic energy distribution caused by re-welding of multi-layer tabs to positive and negative lead-in components after pairing and welding in traditional processes. Simultaneously, by directly stacking multiple first and second single cells along the thickness direction Z to form a stacked core unit, and bending and attaching the external positive tab to the side of the positive lead-in component away from the first cell body, and bending and attaching the external negative tab to the side of the negative lead-in component away from the second cell body, the traditional long tab and S-shaped bending core structure can be eliminated. Furthermore, the positive lead-in component separates the external positive tab from the first cell body, and the negative lead-in component separates the external negative tab from the second cell body, thereby avoiding the risk of tabs inserting into the cell and eliminating short-circuit hazards.

[0008] In some embodiments, in the width direction of the stack core, the stack core has a first side and a second side disposed opposite to each other, a plurality of external positive tabs and a plurality of external negative tabs are located on the first side, a plurality of first positive tabs, a plurality of first negative tabs, a plurality of second positive tabs and a plurality of second negative tabs are located on the second side, the first positive tabs and the first negative tabs are spaced apart in the length direction of the stack core, and the second positive tabs and the second negative tabs are spaced apart in the length direction of the stack core.

[0009] The above configuration avoids the risk of short circuits caused by the positive and negative tabs coming into contact with each other during stacking, and facilitates the connection of the first positive tab and the first negative tab of the first single cell to the second positive tab and the second negative tab of the second single cell, respectively.

[0010] In some embodiments, the stacked core further includes multiple positive connectors, each corresponding to a plurality of first positive tabs. The first and second positive tabs are welded to their respective positive connectors to form a positive connection structure. The stacked core also includes multiple negative connectors, each corresponding to a plurality of first negative tabs. The first and second negative tabs are welded to their respective negative connectors to form a negative connection structure. This allows multiple first single cells to be connected in parallel with multiple second single cells.

[0011] In some embodiments, the stacked core further includes insulating tape, with insulating tape wrapped around both sides of the positive connection structure in its thickness direction, and both the positive connection structure and the insulating tape on both sides thereof being bendable; the negative connection structure is wrapped around both sides of the negative connection structure in its thickness direction, and both the negative connection structure and the insulating tape on both sides thereof being bendable.

[0012] In the above technical solution, by fully wrapping insulating tape on both sides of the thickness direction Z of the positive connection structure and the negative connection structure, the risk of short circuit caused by burrs or displacement after welding can be prevented. The positive connection structure and the negative connection structure have flexible bending ability and can deform synchronously with the folding action, which can improve the adaptability and flexibility of the assembly process.

[0013] In some embodiments, the positive electrode guide includes a positive electrode boss and a positive electrode guide substrate connected to the positive electrode boss. The positive electrode guide substrate is attached to the stacked core, and multiple external positive electrode tabs are bent and attached to the side of the positive electrode guide substrate opposite to the first cell body. The negative electrode guide includes a negative electrode boss and a negative electrode guide substrate connected to the negative electrode boss. The negative electrode guide substrate is attached to the stacked core, and multiple external negative electrode tabs are bent and attached to the side of the negative electrode guide substrate opposite to the second cell body. In this way, the traditional long electrode tabs and S-shaped bends in the stacked core structure can be eliminated. The positive electrode guide substrate separates the external positive electrode tabs from the first cell body, and the negative electrode guide substrate separates the external negative electrode tabs from the second cell body, thereby avoiding the risk of the electrode tabs being inserted into the cell and eliminating the risk of short circuit.

[0014] In some embodiments, the stacked core includes two first single cells and two second single cells, which are stacked sequentially along the thickness direction; the positive electrode drainage substrate includes a positive electrode drainage plate located between two external positive electrode tabs, which are bent and attached to the positive electrode drainage plate; the negative electrode drainage substrate includes a negative electrode drainage plate located between two external negative electrode tabs, which are bent and attached to the negative electrode drainage plate.

[0015] In the above technical solution, the positive electrode substrate has only one positive electrode guide plate, which is placed between two external positive electrode tabs. The two external positive electrode tabs are symmetrically bent from both sides towards the center and attached to the same guide plate surface, which can realize the parallel connection of two first single cells. Similarly, the negative electrode substrate has a single negative electrode guide plate, which is symmetrically attached to the negative electrode guide plate, which can realize the parallel connection of two second single cells, thereby enabling four single cells to be connected in parallel.

[0016] In some embodiments, the stacked core includes two first single cells and two second single cells, with the two second single cells located between the two first single cells. The positive electrode substrate includes a connecting plate and two positive electrode guide plates. The connecting plate has a positive electrode protrusion, and the two positive electrode guide plates are respectively connected to both ends of the connecting plate. Two external negative electrode tabs are located between the two positive electrode guide plates, and the two external positive electrode tabs are bent and attached to the two positive electrode guide plates respectively. The negative electrode substrate includes one negative electrode guide plate, which is located between the two external negative electrode tabs, and the two external negative electrode tabs are bent and attached to the negative electrode guide plate. In this way, two first single cells can be connected in parallel; similarly, two second single cells can be connected in parallel, thereby enabling four single cells to be connected in parallel.

[0017] In some embodiments, the stacked core unit includes two stacked cores arranged side-by-side in the width direction of the stacked cores, with their second sides facing each other. The stacked core unit has a third side and a fourth side arranged opposite each other in the length direction of the stacked cores. The positive electrode drain includes two positive electrode drain substrates, two connecting plates connected to each other and located on the third side, a positive electrode boss disposed on at least one of the two connecting plates, and two positive electrode drain plates connected to one of the connecting plates being bent and electrically connected to two external positive electrode tabs of one of the stacked cores. Two positive electrode drain plates connected to another connecting plate in the first connecting plate are bent and electrically connected to two external positive electrode tabs of another stacked core. The negative electrode drain component includes two connected negative electrode drain bases, with a negative electrode protrusion disposed on at least one of the two negative electrode drain bases. The negative electrode protrusion is located on the fourth side. One of the two negative electrode drain plates is bent and electrically connected to two external negative electrode tabs of one stacked core, and the other of the two negative electrode drain plates is bent and electrically connected to two external negative electrode tabs of the other stacked core. In this way, eight single cells can be connected in parallel.

[0018] According to another aspect of the present invention, a lithium battery is provided, including a housing, at least one cover plate assembly and the aforementioned stacked core assembly, wherein the stacked core assembly is disposed inside the housing and the cover plate assembly is disposed on the housing.

[0019] According to another aspect of the present invention, the present invention provides a method for assembling a stacked core assembly, the method being used to assemble the aforementioned stacked core assembly.

[0020] In some embodiments, the assembly method of the stacked core assembly includes: step S10: preparing a first single cell and a second single cell arranged in parallel, wherein the first positive electrode tab of the first single cell is electrically connected to the second positive electrode tab of the second single cell, and the first negative electrode tab of the first single cell is electrically connected to the second negative electrode tab of the second single cell; step S20: repeating step S10 multiple times to prepare a plurality of dual-core structures, the dual-core structures including the first single cell and the second single cell arranged in parallel; step S30: stacking the plurality of first single cells and the plurality of second single cells along the thickness direction of the stack to form a stack; step 40: bending and attaching the external positive electrode tabs of the plurality of first single cells to the side of the positive electrode guide that is away from the first cell body, and bending and attaching the external negative electrode tabs of the plurality of second single cells to the side of the negative electrode guide that is away from the second cell body, so that the plurality of first single cells and the plurality of second single cells are arranged in parallel.

[0021] In the above technical solution, on the one hand, by pairing the first single cell with the second single cell and completing the interconnection of the tabs inside the cell (i.e., directly welding the first positive tab to the second positive tab and the first negative tab to the second negative tab), a dual-cell structure is formed. Additional external positive and negative tabs are used, with the external positive tab bent and attached to the side of the positive electrode leading element away from the first cell body, and the external negative tab bent and attached to the side of the negative electrode leading element away from the second cell body. This not only reduces the number of times the same tab is welded, but also reduces the thickness of the welding interface, allowing laser or ultrasonic welding energy to be evenly transmitted to each contact surface, thus eliminating outer tab tearing and inner layer weld defects. This significantly improves the reliability and yield of electrical connections, thus solving the problem of uneven ultrasonic energy distribution caused by re-welding of multi-layer tabs to positive and negative leads after pairing and welding in traditional processes. Simultaneously, by directly stacking multiple first and second single cells along the thickness direction Z to form a stacked core unit, and bending and attaching the external positive tab to the side of the positive lead away from the first cell body, and bending and attaching the external negative tab to the side of the negative lead away from the second cell body, the traditional long tab and S-shaped bending core structure can be eliminated. Furthermore, the positive lead separates the external positive tab from the first cell body, and the negative lead separates the external negative tab from the second cell body, thus avoiding the risk of tabs inserting into the cell and eliminating short-circuit hazards.

[0022] In some embodiments, step S10 includes: step S11: stacking a positive electrode sheet having an external positive tab and a first positive tab, a separator, and a negative electrode sheet having a first negative tab to form a first single cell; step S12: stacking a negative electrode sheet having an external negative tab and a second negative tab, a separator, and a positive electrode sheet having a second positive tab to form a second single cell; step S13: welding the first positive tab of the first single cell to the second positive tab of the second single cell using a positive connector, and welding the first negative tab of the first single cell to the second negative tab of the second single cell using a negative connector. This allows for the formation of a first single cell and a second single cell connected in parallel.

[0023] In some embodiments, step S10 includes: step 14: preparing a positive electrode sheet, the positive electrode sheet including an external positive electrode tab, two small positive electrode pieces and an extended positive electrode tab for connecting the two small positive electrode pieces, one of the two small positive electrode pieces having an external positive electrode tab; step 15: preparing a negative electrode sheet, the negative electrode sheet including an external negative electrode tab, two small negative electrode pieces and an extended negative electrode tab for connecting the two small negative electrode pieces, one of the two small negative electrode pieces having an external negative electrode tab; step 16: stacking the positive electrode sheet, the separator and the negative electrode sheet to form a first single cell and a second single cell connected in parallel.

[0024] With the above setup, both the positive and negative electrode plates are composed of two small plates connected by extended tabs. By stacking the positive and negative electrode plates, a dual-cell structure is directly obtained, thus eliminating the need for pairing or welding of the tabs and connecting plates.

[0025] In some embodiments, there are two dual-cell structures. Step S30 includes: arranging the two dual-cell structures in a cross-shaped configuration; folding three of the two first single cells and two second single cells, and stacking them onto the remaining one of the two first single cells and two second single cells to form a stacked core. In this way, the tabs can be stretched by flipping and folding the single cells, allowing the two first single cells and two second single cells to be stacked in the thickness direction X, resulting in a four-cell parallel structure to form a stacked core.

[0026] By applying the technical solution of this invention, on the one hand, after pairing the first single cell with the second single cell, the electrode tabs are interconnected inside the cell (i.e., the first positive electrode tab and the second positive electrode tab, and the first negative electrode tab and the second negative electrode tab are directly welded), and additional external positive and negative electrodes are used. The external positive electrode tab is bent and attached to the side of the positive electrode guide that is away from the first cell body, and the external negative electrode tab is bent and attached to the side of the negative electrode guide that is away from the second cell body. In this way, not only can the number of times the same electrode tab is welded be reduced, but also the external positive electrode tab is only welded to the positive electrode guide and the external negative electrode tab is only welded to the negative electrode guide. This also reduces the thickness of the welding interface, so that the laser or ultrasonic welding energy can be evenly transmitted to each contact surface, thereby eliminating outer electrode tab tearing and inner layer poor soldering defects. This significantly improves the reliability and yield of electrical connections, thus solving the problem of uneven ultrasonic energy distribution caused by re-welding of multi-layer tabs to positive and negative lead-in components after pairing and welding in traditional processes. Simultaneously, by directly stacking multiple first and second single cells along the thickness direction Z to form a stacked core unit, and bending and attaching the external positive tab to the side of the positive lead-in component away from the first cell body, and bending and attaching the external negative tab to the side of the negative lead-in component away from the second cell body, the traditional long tab and S-shaped bending core structure can be eliminated. Furthermore, the positive lead-in component separates the external positive tab from the first cell body, and the negative lead-in component separates the external negative tab from the second cell body, thereby avoiding the risk of tabs inserting into the cell and eliminating short-circuit hazards. Attached Figure Description

[0027] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0028] Figure 1 This is a schematic diagram of the positive and negative electrode plates and tabs corresponding to the first single cell in Embodiment 1 of the present invention;

[0029] Figure 2 This is a schematic diagram of the positive and negative electrode plates and tabs corresponding to the second single cell in Embodiment 1 of the present invention;

[0030] Figure 3 This is a schematic diagram showing the welding and adhesive application of the first and second single-cell batteries in Embodiment 1 of the present invention.

[0031] Figure 4 This is a schematic diagram of the cross-arrangement of two sets of dual-cell structures in Embodiment 1 of the present invention;

[0032] Figure 5(a) is a front view of the two sets of cross-arranged dual-cell structures after they are folded together in Embodiment 1 of the present invention.

[0033] Figure 5(b) is a reverse side view of the two sets of cross-arranged dual-cell structures after they are folded together in Embodiment 1 of the present invention.

[0034] Figure 6 This is a schematic diagram showing the positive and negative electrode leads and the electrode tabs being welded and glued together in Embodiment 1 of the present invention;

[0035] Figure 7 This is a schematic diagram of the positive and negative electrode current-guiding components in Embodiment 1 of the present invention;

[0036] Figure 8 This is a schematic diagram of the four battery cells installed in the housing and welded together with the cover plate assembly in Embodiment 1 of the present invention;

[0037] Figure 9 This is a schematic diagram of the cross-arrangement of two sets of dual-cell structures in Embodiment 2 of the present invention;

[0038] Figure 10 This is a schematic diagram of the relative positions of the positive and negative electrode draining components and the electrode tabs in Embodiment 2 of the present invention;

[0039] Figure 11 This is a schematic diagram of the positive and negative electrode plates and single cell in Embodiment 3 of the present invention;

[0040] Figure 12 This is a schematic diagram of the battery cell pairing, welding, and adhesive application in Embodiment 4 of the present invention;

[0041] Figure 13(a) is a schematic diagram of the four-cell folding structure in Embodiment 4 of the present invention;

[0042] Figure 13(b) is a schematic diagram of the structure of the four-cell battery after folding in Embodiment 4 of the present invention;

[0043] Figure 14(a) is a schematic diagram of the cross-stacked structure of two sets of four-cell battery structures in Embodiment 4 of the present invention;

[0044] Figure 14(b) is a front view of the two sets of four-cell structures in Figure 14(a) being cross-stacked;

[0045] Figure 15(a) is a schematic diagram of the stacked core assembly of Embodiment 4 of the present invention in one direction;

[0046] Figure 15(b) is a schematic diagram of the negative electrode drain of the stacked core assembly in Figure 15(a);

[0047] Figure 15(c) is a schematic diagram of the stacked core assembly of Embodiment 4 of the present invention from another direction;

[0048] Figure 15(d) is a schematic diagram of the positive electrode current guide of the stacked core assembly in Figure 15(c);

[0049] Figure 16(a) is a schematic diagram of the eight-cell structure and cover plate assembly in one direction in Embodiment 4 of the present invention;

[0050] Figure 16(b) is a schematic diagram of the eight-cell structure and cover plate assembly in another direction in Embodiment 4 of the present invention.

[0051] The above figures include the following reference numerals:

[0052] 100. Stacked core; 10. Positive electrode sheet; 101. Positive electrode tab; 102. Positive electrode coating area; 20. Negative electrode sheet; 201. Negative electrode tab; 202. Negative electrode coating area; 30. First single cell; 40. Second single cell; 31. First cell body; 32. First positive electrode tab; 33. First negative electrode tab; 34. External positive electrode tab; 41. Second cell body; 42. Second positive electrode tab; 43. Second negative electrode tab; 44. External negative electrode tab; 501. Positive connector; 502. Negative connector; 60. Insulating tape; 701. Positive electrode lead; 702. Negative electrode lead; 7011. Positive electrode boss; 7012. Positive electrode lead substrate; 7021. Negative electrode boss; 7022. Negative electrode lead substrate; 7013. Connecting plate; 7014. Positive electrode lead plate; 90. Housing; 80. Cover assembly; 801. Substrate; 802. Positive terminal; 803. Negative terminal; 804. Explosion-proof valve; 805. Injection port. Detailed Implementation

[0053] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0054] It should be noted that the width direction of the positive electrode sheet, negative electrode sheet, first single cell, second single cell, and stacked core is the X direction, the length direction of the positive electrode sheet, negative electrode sheet, first single cell, second single cell, and stacked core is the Y direction, and the thickness direction of the positive electrode sheet, negative electrode sheet, first single cell, second single cell, and stacked core is the Z direction.

[0055] like Figures 1 to 1 As shown in 6(b), an embodiment of the present invention provides a stacked core assembly, including: a stacked core unit including a stacked core 100, the stacked core 100 including a plurality of first single cells 30 and a plurality of second single cells 40 stacked along the thickness direction Z of the stacked core 100, the plurality of first single cells 30 and the plurality of second single cells 40 being arranged in a one-to-one correspondence, the first single cell 30 including a first cell body 31, a first positive electrode 32, a first negative electrode 33 and an external positive electrode 34, the second single cell 40 including a second cell body 41, a second positive electrode 42, a second negative electrode 43 and an external negative electrode 44, wherein the first negative electrode 33 and the corresponding second negative electrode 43 are electrically connected. The first positive electrode tab 32 is electrically connected to the corresponding second positive electrode tab 42; the positive electrode guide 701 and the negative electrode guide 702 are located between the two sides of the stacked core unit in the thickness direction Z, the positive electrode guide 701 is located between the two sides of the stacked core unit in the thickness direction Z, the external positive electrode tabs 34 of the multiple first single cells 30 are bent and attached to the side of the positive electrode guide 701 away from the first cell body 31, and the external negative electrode tabs 44 of the multiple second single cells 40 are bent and attached to the side of the negative electrode guide 702 away from the second cell body 41, so that the multiple first single cells 30 and the multiple second single cells 40 are arranged in parallel.

[0056] In the above technical solution, on the one hand, by pairing the first single cell 30 and the second single cell 40 and completing the interconnection of the electrodes inside the cell (i.e., directly welding the first positive electrode 32 to the second positive electrode 42 and the first negative electrode 33 to the second negative electrode 43), and using additional external positive electrode 34 and external negative electrode 44, with the external positive electrode 34 bent and attached to the side of the positive electrode current guide 701 away from the first cell body 31, and the external negative electrode 44 bent and attached to the side of the negative electrode current guide 702 away from the second cell body 41, this not only reduces the number of times the same electrode is welded, but also reduces the thickness of the welding interface by having the external positive electrode 34 welded only to the positive electrode current guide 701 and the external negative electrode 44 welded only to the negative electrode current guide 702, allowing the laser or ultrasonic welding energy to be evenly transmitted to each contact surface, thereby eliminating outer electrode tearing and inner layer poor welding defects, significantly improving the efficiency of welding. Improving the reliability and yield of electrical connections solves the problem of uneven ultrasonic energy distribution caused by re-welding of multi-layer tabs to the positive electrode lead 701 and negative electrode lead 702 after pairing and welding in traditional processes. Simultaneously, by directly stacking multiple first single cells 30 and second single cells 40 along the thickness direction Z of the stacked core 100 to form a stacked core unit, and bending and attaching the external positive tab 34 to the side of the positive electrode lead 701 away from the first cell body 31, and bending and attaching the external negative tab 44 to the side of the negative electrode lead 702 away from the second cell body 41, the traditional long tab and S-shaped bending core structure can be eliminated. Furthermore, the positive electrode lead 701 separates the external positive tab 34 from the first cell body 31, and the negative electrode lead 702 separates the external negative tab 44 from the second cell body 41, thus avoiding the risk of tabs inserting into the cell and eliminating short-circuit hazards.

[0057] like Figures 1 to 1 As shown in 6(b), in an embodiment of the present invention, the stacked core 100 has a first side and a second side arranged opposite to each other in the width direction X. A plurality of external positive tabs 34 and a plurality of external negative tabs 44 are located on the first side, and a plurality of first positive tabs 32, a plurality of first negative tabs 33, a plurality of second positive tabs 42 and a plurality of second negative tabs 43 are located on the second side. The first positive tabs 32 and the first negative tabs 33 are spaced apart in the length direction Y of the stacked core 100, and the second positive tabs 42 and the second negative tabs 43 are spaced apart in the length direction Y of the stacked core 100.

[0058] The above configuration avoids the risk of short circuit caused by the positive and negative tabs coming into contact with each other during stacking, and facilitates the connection of the first positive tab and the first negative tab of the first single cell 30 to the second positive tab and the second negative tab of the second single cell 40, respectively.

[0059] like Figures 1 to 1As shown in 6(b), in an embodiment of the present invention, the stacked core 100 further includes a plurality of positive connectors 501, each corresponding to a plurality of first positive tabs 32. The first positive tabs 32 and second positive tabs 42 are both welded to their corresponding positive connectors 501 to form a positive connection structure. The stacked core 100 also includes a plurality of negative connectors 502, each corresponding to a plurality of first negative tabs 33. The first negative tabs 33 and second negative tabs 43 are both welded to their corresponding negative connectors 502 to form a negative connection structure. This allows for the parallel connection of a plurality of first single cells 30 with a plurality of second single cells 40.

[0060] In some embodiments, the negative connector 502 is a negative connector piece, and the positive connector 501 is a positive connector piece.

[0061] like Figures 1 to 1 As shown in 6(b), in an embodiment of the present invention, the stacked core 100 further includes insulating tape 60. The positive connection structure is wrapped with insulating tape 60 on both sides of its thickness direction Z. The positive connection structure and the insulating tape 60 on both sides can be bent. The negative connection structure is wrapped with insulating tape 60 on both sides of its thickness direction Z. The negative connection structure and the insulating tape 60 on both sides can be bent.

[0062] In the above technical solution, by fully wrapping insulating tape 60 on both sides of the thickness direction Z of the positive connection structure and the negative connection structure, the risk of short circuit caused by burrs or displacement after welding can be prevented. The positive connection structure and the negative connection structure have flexible bending ability and can deform synchronously with the folding action, which can improve the adaptability and flexibility of the assembly process.

[0063] like Figures 1 to 1 As shown in 6(b), in an embodiment of the present invention, the positive electrode guide 701 includes a positive electrode boss 7011 and a positive electrode guide substrate 7012 connected to the positive electrode boss 7011. The positive electrode guide substrate 7012 is attached to the stacked core 100, and a plurality of external positive electrode tabs 34 are bent and attached to the side of the positive electrode guide substrate 7012 away from the first cell body 31. The negative electrode guide 702 includes a negative electrode boss 7021 and a negative electrode guide substrate 7022 connected to the negative electrode boss 7021. The negative electrode guide substrate 7022 is attached to the stacked core 100, and a plurality of external negative electrode tabs 44 are bent and attached to the side of the negative electrode guide substrate 7022 away from the second cell body 41. In this way, the traditional long tab and S-shaped bending core structure can be eliminated, and the positive electrode current-leading substrate 7012 separates the external positive tab 34 from the first cell body 31, and the negative electrode current-leading substrate 7022 separates the external negative tab 44 from the second cell body 41, thereby avoiding the risk of the tab being inserted into the cell and eliminating the risk of short circuit.

[0064] like Figures 1 to 8As shown, in one embodiment of the present invention, the stacked core 100 includes two first single cells 30 and two second single cells 40, which are stacked sequentially along the thickness direction Z; the positive electrode current-guiding substrate 7012 includes a positive electrode current-guiding plate 7014, which is located between two external positive electrode tabs 34, and the two external positive electrode tabs 34 are bent and attached to the positive electrode current-guiding plate 7014; the negative electrode current-guiding substrate 7022 includes a negative electrode current-guiding plate, which is located between two external negative electrode tabs 44, and the two external negative electrode tabs 44 are bent and attached to the negative electrode current-guiding plate.

[0065] In the above technical solution, the positive electrode substrate 7012 has only one positive electrode guide plate 7014, which is placed between two external positive electrode tabs 34. The two external positive electrode tabs 34 are symmetrically bent from both sides to the center and attached to the same guide plate surface, which can realize the parallel connection of two first single cells 30. Similarly, the negative electrode substrate 7022 has a single negative electrode guide plate, and the two external negative electrode tabs 44 are symmetrically attached to the negative electrode guide plate, which can realize the parallel connection of two second single cells 40, thereby enabling four single cells to be connected in parallel.

[0066] like Figure 9 and Figure 10 As shown, in one embodiment of the present invention, the stacked core 100 includes two first single cells 30 and two second single cells 40, with the two second single cells 40 located between the two first single cells 30; the positive electrode current-guiding substrate 7012 includes a connecting plate 7013 and two positive electrode current-guiding plates 7014, with a positive electrode boss 7011 provided on the connecting plate 7013, and the two positive electrode current-guiding plates 7014 respectively connected to both ends of the connecting plate 7013, with two external negative electrode tabs 44 located between the two positive electrode current-guiding plates 7014, and the two external positive electrode tabs 34 respectively bent and attached to the two positive electrode current-guiding plates 7014; the negative electrode current-guiding substrate 7022 includes a negative electrode current-guiding plate, with the negative electrode current-guiding plate located between the two external negative electrode tabs 44, and the two external negative electrode tabs 44 bent and attached to the negative electrode current-guiding plate. In this way, two first single cells 30 can be connected in parallel; similarly, two second single cells 40 can be connected in parallel, thus enabling four single cells to be connected in parallel.

[0067] like Figure 12As shown in Figure 16(b), in one embodiment of the present invention, the stacked core unit includes two stacked cores 100, which are arranged side by side in the width direction X of the stacked cores 100, and their second sides are arranged facing each other. The stacked core unit has a third side and a fourth side arranged opposite each other in the length direction Y of the stacked cores 100. The positive electrode drain member 701 includes two positive electrode drain bases 7012, two connecting plates 7013 connected to each other and located on the third side, and a positive electrode boss 7011 is one and disposed on at least one of the two connecting plates 7013. The two positive electrode drain plates 7014 connected to one of the two connecting plates 7013 are bent and connected to the two external positive electrodes of one of the stacked cores 100. The ear 34 is electrically connected. The two positive electrode drain plates 7014, connected to the other connecting plate 7013, are bent and then electrically connected to the two external positive electrode ears 34 of the other stacked core 100. The negative electrode drain component 702 includes two connected negative electrode drain bases 7022. A negative electrode protrusion 7021 is disposed on at least one of the two negative electrode drain bases 7022, located on the fourth side. One of the two negative electrode drain plates is bent and then electrically connected to the two external negative electrode ears 44 of one of the stacked cores 100, and the other of the two negative electrode drain plates is bent and then electrically connected to the two external negative electrode ears 44 of the other stacked core 100. In this way, eight single cells can be connected in parallel.

[0068] like Figure 8 As shown in Figures 16(a) and 16(b), an embodiment of the present invention provides a lithium battery including a housing 90, at least one cover plate assembly 80 and the aforementioned stacked core assembly, wherein the stacked core assembly is disposed inside the housing 90 and the cover plate assembly 80 covers the housing 90.

[0069] The lithium battery described above has all the advantages of the stacked core assembly described above, which will not be repeated here.

[0070] An embodiment of the present invention provides an assembly method for a stacked core assembly, which is used to assemble the stacked core assembly.

[0071] In an embodiment of the present invention, the assembly method of the stacked core assembly includes: step S10: preparing a first single cell 30 and a second single cell 40 arranged in parallel, wherein the first positive electrode 32 of the first single cell 30 is electrically connected to the second positive electrode 42 of the second single cell 40, and the first negative electrode 33 of the first single cell 30 is electrically connected to the second negative electrode 43 of the second single cell 40; step S20: repeating step S10 multiple times to prepare multiple dual-core structures, the dual-core structure including the first single cell 30 and the second single cell 40 arranged in parallel. 0; Step S30: Stack multiple first single cells 30 and multiple second single cells 40 along the thickness direction Z of the stacked core 100 to form a stacked core 100; Step 40: Bend and attach the external positive electrode tabs 34 of multiple first single cells 30 to the side of the positive electrode current guide 701 away from the first cell body 31, and bend and attach the external negative electrode tabs 44 of multiple second single cells 40 to the side of the negative electrode current guide 702 away from the second cell body 41, so that multiple first single cells 30 and multiple second single cells 40 are connected in parallel.

[0072] In the above technical solution, on the one hand, by pairing the first single cell 30 and the second single cell 40, the electrode tabs are interconnected inside the cell (i.e., the first positive electrode tab 32 and the second positive electrode tab 42, and the first negative electrode tab 33 and the second negative electrode tab 43 are directly welded) to form a dual-cell structure. Additional external positive electrode tabs 34 and 44 are used, with the external positive electrode tab 34 bent and attached to the side of the positive electrode current guide 701 facing away from the first cell body 31, and the external negative electrode tab 44 bent and attached to the side of the negative electrode current guide 702 facing away from the second cell body 41. This not only reduces the number of times the same electrode tab is welded, but also reduces the thickness of the welding interface, as the external positive electrode tab 34 is only welded to the positive electrode current guide 701 and the external negative electrode tab 44 is only welded to the negative electrode current guide 702. This allows the laser or ultrasonic welding energy to be evenly transmitted to each contact surface, eliminating outer electrode tab tearing and inner layer incomplete welding. This significantly improves the reliability and yield of electrical connections, thus solving the problem of uneven ultrasonic energy distribution caused by the re-welding of multi-layer tabs to the positive electrode lead 701 and negative electrode lead 702 after pairing and welding in traditional processes. Simultaneously, by directly stacking multiple first single cells 30 and second single cells 40 along the thickness direction Z of the stacked core 100 to form a stacked core unit, and bending and attaching the external positive tab 34 to the side of the positive electrode lead 701 away from the first cell body 31, and bending and attaching the external negative tab 44 to the side of the negative electrode lead 702 away from the second cell body 41, the traditional long tab and S-shaped bending core structure can be eliminated. Furthermore, the positive electrode lead 701 separates the external positive tab 34 from the first cell body 31, and the negative electrode lead 702 separates the external negative tab 44 from the second cell body 41, thereby avoiding the risk of tabs inserting into the cell and eliminating short-circuit hazards.

[0073] like Figure 1 and Figure 2 As shown, in one embodiment of the present invention, step S10 includes: step S11: stacking a positive electrode 10 having an external positive tab 34 (positive tab 101) and a first positive tab 32 (positive tab 101), a separator, and a negative electrode 20 having a first negative tab 33 (negative tab 201) to form a first single cell 30; step S12: stacking a negative electrode 20 having an external negative tab 44 (negative tab 201) and a second negative tab 43 (negative tab 201), a separator, and a positive electrode 10 having a second positive tab 42 (positive tab 101) to form a second single cell 40; step S13: welding the first positive tab 32 of the first single cell 30 to the second positive tab 42 of the second single cell 40 through a positive connector 501, and welding the first negative tab 33 of the first single cell 30 to the second negative tab 43 of the second single cell 40 through a negative connector 502. In this way, the first single cell 30 and the second single cell 40 can be connected in parallel.

[0074] like Figure 11 As shown, in one embodiment of the present invention, step S10 includes: Step 14: preparing a positive electrode 10, the positive electrode 10 including an external positive electrode tab 34, two small positive electrode pieces and an extended positive electrode tab for connecting the two small positive electrode pieces, one of the two small positive electrode pieces having an external positive electrode tab 34; Step 15: preparing a negative electrode 20, the negative electrode 20 including an external negative electrode tab 44, two small negative electrode pieces and an extended negative electrode tab for connecting the two small negative electrode pieces, one of the two small negative electrode pieces having an external negative electrode tab 44; Step 16: stacking the positive electrode 10, the separator and the negative electrode 20 to form a first single cell 30 and a second single cell 40 connected in parallel.

[0075] With the above setup, both the positive and negative electrode plates are composed of two small plates connected by extended tabs. By stacking the positive and negative electrode plates, a dual-cell structure is directly obtained, thus eliminating the need for pairing or welding of the tabs and connecting plates.

[0076] like Figure 4 and Figure 9 As shown, in an embodiment of the present invention, there are two dual-cell structures. Step S30 includes: arranging the two dual-cell structures in a cross-shaped pattern; folding three of the two first single cells 30 and two second single cells 40, and stacking them onto the remaining one of the two first single cells 30 and two second single cells 40 to form a stacked core 100. In this way, the tabs can be stretched by flipping and folding the single cells, allowing the two first single cells 30 and two second single cells 40 to be stacked in the thickness direction X, resulting in a four-cell parallel structure to form the stacked core 100.

[0077] The assembly method of the above-mentioned stacked core assembly has all the advantages of the stacked core assembly, and will not be repeated here.

[0078] Example 1

[0079] Figure 1 This is a schematic diagram of the positive and negative electrode plates and tabs corresponding to the first single cell 30 in Embodiment 1 of the present invention. The positive electrode plate 10 is formed by uniformly coating a positive electrode material onto an aluminum foil and then rolling and slitting it. The uncoated aluminum foil is the positive tab 101. The positive electrode plate 10 has a bipolar structure. If the center of the positive electrode coating area 102 is taken as the origin of the coordinate system, the two positive tabs 101 are located in the +X and -X directions of the electrode width direction (X direction), respectively. The center of the positive tab 101 located in the -X direction is located at the origin of the electrode length direction (Y direction) (i.e., it can form an external positive tab 34); the positive tab 101 located in the +X direction is located in the -Y direction of the electrode length direction (Y direction) (i.e., it can form a first positive tab 32). The negative electrode 20 is formed by uniformly coating a negative electrode material onto a copper foil and then rolling and slitting it. The uncoated copper foil is the negative electrode tab 201. The negative electrode 20 has a single tab structure. If the center of the negative electrode coating area 202 is taken as the origin of the coordinate system, the negative electrode tab 201 is located in the +X direction of the electrode width direction (X direction) and in the -Y direction of the electrode length direction (Y direction), thus forming the first negative electrode tab 33. The distance from the outer side of the positive electrode tab 101 located in the +X direction to the edge of the positive electrode (-Y direction) is T1, and the distance from the inner side of the negative electrode tab 201 located in the +X direction to the edge of the negative electrode (-Y direction) is T2, satisfying T1 > T2. Then, the electrodes are stacked from bottom to top in the order of separator-negative electrode 20-separator-positive electrode 10-separator... to obtain the first single cell 30. Then, the corresponding multi-layer positive electrode tab 101 and multi-layer negative electrode tab 201 are gathered in the middle of the cell thickness direction. Preferably, the tabs can be gathered by ultrasonic welding.

[0080] Figure 2This is a schematic diagram of the positive and negative electrode plates and tabs corresponding to the second single cell 40 in Embodiment 1 of the present invention. The positive electrode plate 10 is formed by uniformly coating positive electrode material on aluminum foil and then rolling and cutting it. The uncoated aluminum foil is the positive tab 101. The positive electrode plate 10 has a single tab structure. If the center of the positive electrode coating area 102 is taken as the origin of the coordinate system, the positive tab 101 is located in the -X direction of the electrode width direction (X direction) and in the -Y direction of the electrode length direction (Y direction) to form the second positive tab 42. The negative electrode 20 is formed by uniformly coating a negative electrode material onto a copper foil and then rolling and slitting it. The uncoated copper foil is the negative electrode tab 201. The negative electrode 20 has a bipolar structure. If the center of the negative electrode coating area 202 is taken as the origin of the coordinate system, the negative electrode tab 201 is located in the +X and -X directions of the electrode width direction (X direction). The center of the negative electrode tab 201 located in the +X direction is located at the origin of the electrode length direction (Y direction) (i.e., it can form an external negative electrode tab 44); the negative electrode tab 201 located in the -X direction is located in the -Y direction of the electrode length direction (Y direction) (i.e., it can form a second negative electrode tab 43). The distance from the outer side of the positive electrode tab 101 located in the -X direction to the edge of the positive electrode (-Y direction) is T1, and the distance from the inner side of the negative electrode tab 201 located in the -X direction to the edge of the negative electrode (-Y direction) is T2, satisfying T1 > T2. The electrodes are stacked sequentially from bottom to top in the order of separator-negative electrode 20-separator-positive electrode 10-separator... to obtain the second single cell 40. Then, the corresponding multi-layer positive electrode tab 101 and multi-layer negative electrode tab 201 are gathered in the middle of the cell thickness direction. Preferably, the tabs can be gathered by ultrasonic welding.

[0081] Figure 3 This is a schematic diagram illustrating the welding and adhesive application of the first single-cell 30 and the second single-cell 40 in Embodiment 1 of the present invention. Take one set of the first single-cell 30 and the second single-cell 40 respectively, and align their corresponding positive tabs 101 and negative tabs 201 in pairs (i.e., the first positive tab 32 corresponds to the second positive tab 42, and the first negative tab 33 corresponds to the second negative tab 43). Then, weld both the first positive tab 32 and the second positive tab 42 to the positive connector 501, and weld both the first negative tab 33 and the second negative tab 43 to the negative connector 502. Preferably, ultrasonic welding or laser welding can be used. Finally, cover the upper and lower weld marks with insulating tape 60 to obtain the dual-cell structure.

[0082] Figure 4 This is a schematic diagram of the cross-arrangement of two sets of dual-cell structures in Embodiment 1 of the present invention. Figure 3 On the basis of, take Figure 3 The two sets of dual-cell structures shown are arranged in a cross pattern, and then... Figure 4 The battery cell is folded in the direction shown.

[0083] Figures 5(a) and 5(b) are schematic diagrams of the front and back sides of the two sets of cross-arranged dual-cell structures in Embodiment 1 of the present invention after being folded together. As can be seen from the front side of Figure 5(a), the external positive tabs 34 corresponding to the two first single cells 30 and the external negative tabs 44 corresponding to the two second single cells 40 are close to each other; as can be seen from the back side of Figure 5(b), the two negative tabs 201 (the first negative tab and the second negative tab) are located at both ends, and the two positive tabs 101 (the first positive tab and the second positive tab) are located in the middle area, and both the positive tabs 101 and the negative tabs 201 are stretched and tightly attached to the end face of the cell.

[0084] Figure 6 This is a schematic diagram of the welding and adhesive application of the current-draining component and the electrode tab in Embodiment 1 of the present invention. Based on Figures 5(a) and 5(b), the positive electrode current-draining component 701 and the negative electrode current-draining component 702 are placed in the middle of the two positive electrode tabs 101 (two external positive electrode tabs) and the two negative electrode tabs 201 (two external negative electrode tabs), respectively. Then, the positive electrode tabs 101 are folded onto the positive electrode current-draining substrate 7012 corresponding to the positive electrode current-draining component 701, and the negative electrode tabs 201 are folded onto the negative electrode current-draining substrate 7022 corresponding to the negative electrode current-draining component 702. Subsequently, the electrode tabs and the current-draining substrates are welded together by laser. Finally, the solder marks are covered with insulating tape 60 to obtain the four-cell structure.

[0085] Figure 7 This is a schematic diagram of the draining device in Embodiment 1 of the present invention. The draining device is made of thin sheet metal. The positive electrode is made of aluminum and the negative electrode draining device is made of copper. A positive electrode boss 7011 and a negative electrode boss 7021 are respectively provided on the draining device. The bosses have a hollow internal structure, which can reduce the weight of the entire draining device.

[0086] Figure 8 This is a schematic diagram showing the four battery cells installed in the housing and welded together with the cover plate assembly in Embodiment 1 of the present invention. Figure 6 Based on this, the four-cell structure is placed into a housing 90 with one open end. Then, a cover plate assembly 80 is placed on the end face of the housing 90. The cover plate assembly 80 consists of a substrate 801, a positive terminal 802, a negative terminal 803, an explosion-proof valve 804, and a liquid injection hole 805. The positive terminal 802 and the negative terminal 803 are provided with through holes, which mate with the positive terminal boss 7011 and the negative terminal boss 7021, respectively. Finally, the positive terminal boss 7011 is welded to the positive terminal boss 802, the negative terminal boss 7021 is welded to the negative terminal boss 803, and the substrate 801 is welded to the end face of the housing 90, thus completing the parallel assembly of the four cells.

[0087] Example 2

[0088] Figure 9This is a schematic diagram of the cross-arrangement of two sets of dual-cell structures in Embodiment 2 of the present invention. Figure 3 On the basis of, take Figure 3 The two dual-cell structures shown are arranged in a cross pattern. Figure 4 Compared with Embodiment 1, the relative positions of the cells are different in Embodiment 2.

[0089] Figure 10 This is a structural schematic diagram showing the relative positions of the drainage element and the electrode tab in Embodiment 2 of the present invention. Figure 9 The battery cell is folded in the direction shown. From the front of the four cells, it can be seen that the two positive tabs 101 (two external positive tabs) are located on either side of the cell's thickness, and the two negative tabs 201 (two external negative tabs) are close to each other and located in the middle of the cell's thickness. Then, the positive electrode guide 701 and negative electrode guide 702 are placed at the positive tabs 101 and 201, respectively. The negative electrode guide 702 has only one negative electrode guide plate, while the positive electrode guide 701 has two positive electrode guide plates 7014. The external positive tab 34 is folded onto the corresponding positive electrode guide plate 7014 of the positive electrode guide 701, and the external negative tab 44 is folded onto the corresponding negative electrode guide plate of the negative electrode guide 702. The tabs and guide plates are then welded together using a laser. Finally, the solder marks are covered with insulating tape 60 to obtain the four-cell structure. Finally, according to... Figure 8 The steps shown complete the parallel assembly of the four battery cells.

[0090] The difference between Embodiment 2 and Embodiment 1 of the present invention is that the relative positions of the positive and negative tabs (external positive tab and external negative tab) of the two sets of dual-cell structures are different, which leads to different relative positions of the positive and negative tabs in the four-cell structure after the cell is flipped, resulting in different structures of the subsequent positive lead plate.

[0091] Example 3

[0092] Figure 11This is a schematic diagram of the positive and negative electrode sheets and a single battery cell in Embodiment 3 of the present invention. Compared with Embodiment 1, the positive electrode sheet 10 in Embodiment 3 is composed of two small positive electrode sheets connected by a positive electrode tab 101 (extended positive electrode tab); the negative electrode sheet 20 is composed of two small negative electrode sheets connected by a negative electrode tab 201 (extended negative electrode tab). The electrode sheets are stacked sequentially from bottom to top in the manner of separator-negative electrode sheet 20-separator-positive electrode sheet 10-separator... to obtain a dual-cell structure. Then, the corresponding multi-layer positive electrode tabs 101 (which can form an external positive electrode tab 34) and multi-layer negative electrode tabs 201 (which can form an external negative electrode tab 44) are respectively gathered in the middle of the cell thickness direction. Finally, the entire positive electrode tab 101 (extended positive electrode tab) and negative electrode tab 201 (extended negative electrode tab) located between the dual cells are covered with insulating tape 60. Preferably, ultrasonic welding can be used to gather the electrode tabs. Finally, each can be done according to Example 1 ( Figures 4-8 Example 2 Figure 9 and Figure 10 Perform the parallel assembly of four battery cells as shown in the steps indicated.

[0093] The difference between Embodiment 3 of the present invention and Embodiments 1 and 2 is that: the positive and negative electrode plates corresponding to Embodiments 1 and 2 are both composed of a single small piece, and a total of four different electrode plate structures (two positive electrode plate forms + two negative electrode plate forms) are required to obtain the required first single cell and second single cell. The first single cell and the second single cell also need to be paired and the tabs and connecting pieces are welded. However, the positive and negative electrode plates corresponding to Embodiment 3 of the present invention are both composed of two small pieces connected by extended tabs. The dual-cell structure is directly obtained by stacking the positive and negative electrode plates, without the need for pairing and welding of tabs and connecting pieces.

[0094] Example 4

[0095] Figure 12 This is a schematic diagram of the battery cell pairing, welding, and adhesive application in Embodiment 4 of the present invention. Take two... Figure 1 The first single cell 30, with its electrode stacked as shown, has its multi-layered positive electrode tabs 101 located in the -X direction ultrasonically welded together at the center of its thickness (forming an external positive electrode tab 34). Two of these first single cells 30 are stacked along the Z direction to obtain a parallel dual-cell configuration. The positive electrode tabs 101 and negative electrode tabs 201 on the same side of the parallel dual-cell configuration are then ultrasonically welded together at the center of the dual-cell thickness, thus forming two connected first positive electrode tabs and two connected first negative electrode tabs. Two... Figure 2The second single cell 40, which has completed electrode stacking, has its multi-layer negative electrode tabs 201 located in the +X direction gathered together in the middle of the single cell thickness direction by ultrasonic welding (which can form an external negative electrode tab 44); the two second single cells 40 are stacked along the Z direction to obtain a parallel type II double cell; the positive electrode tabs 101 and negative electrode tabs 201 located on the same side of the parallel type II double cell are gathered together in the middle of the double cell thickness direction by ultrasonic welding, thus forming two connected second positive electrode tabs and two connected second negative electrode tabs. Take one set of parallel-connected Class I dual-cell batteries and one set of parallel-connected Class II dual-cell batteries respectively, and align their corresponding positive tabs 101 and negative tabs 201 in pairs (i.e., the first positive tab and the second positive tab correspond to each other, and the first negative tab and the second negative tab correspond to each other). Then, weld the positive tabs 101 (the first positive tab and the second positive tab) on both sides to the positive connector 501, and the negative tabs 201 (the first negative tab and the second negative tab) on both sides to the negative connector 502. Preferably, ultrasonic welding or laser welding can be used. Finally, cover the upper and lower solder marks with insulating tape 60 to obtain a four-cell battery structure.

[0096] Figures 13(a) and 13(b) are schematic diagrams of the four-cell folding structure in Embodiment 4 of the present invention. Figure 12 Based on this, the four single cells are folded according to the methods shown in Figure 13(a) and Figure 13(b), respectively, and the resulting three-dimensional structural schematic diagram and partial enlarged view are shown in Figure 13(a) and Figure 13(b).

[0097] Figures 14(a) and 14(b) are schematic diagrams of the cross-stacked structure of two sets of four-cell battery structures in Embodiment 4 of the present invention. Two sets of four-cell battery structures shown in Figure 13(b) are arranged and nested as shown in Figure 14(b) to obtain an eight-cell battery structure.

[0098] Figures 15(a), 15(b), 15(c) and 15(d) are schematic diagrams of the relative positions of the drainage element and the electrode in Embodiment 4 of the present invention. The positive electrode lead 701 and the negative electrode lead 702 are placed at the external positive electrode tab 34 and the external negative electrode tab 44, respectively. The negative electrode lead 702 has two negative electrode lead substrates 7022, that is, two negative electrode lead plates, while the positive electrode lead 701 has two positive electrode lead substrates 7012. Each positive electrode lead substrate 7012 has two positive electrode lead plates 7014, that is, the positive electrode lead 701 has four positive electrode lead plates 7014. The external positive electrode tab 34 is folded onto the corresponding positive electrode lead plate 7014 of the positive electrode lead 701, and the external negative electrode tab 44 is folded onto the corresponding negative electrode lead substrate 7022 of the negative electrode lead 702. Then, the tabs and the lead substrates are welded together by laser. Finally, the solder marks are covered with insulating tape 60 to obtain an eight-cell structure.

[0099] Figures 16(a) and 16(b) are schematic diagrams showing the installation positions of the eight-cell structure and cover plate assembly in Embodiment 4 of the present invention. Based on Figure 15(d), the positive electrode boss 7011 and the negative electrode boss 7021 are located at both ends of the cell length (Y direction). After the electrode tabs are welded to the current-guiding substrate, the external positive electrode tab 34 and the positive current-guiding substrate 7012, and the external negative electrode tab 44 and the negative current-guiding substrate 7022 are wrapped with insulating tape. Then, the eight-cell structure is inserted into the shell 90 with openings at both ends. Two sets of cover plate assemblies 80 are taken. One set of cover plate assembly 80 consists of a substrate 801, a negative electrode post 803, and an explosion-proof valve 804. The other set of cover plate assembly 80 consists of a substrate 801, a positive electrode post 802, and an injection hole 805. Through holes are provided on the positive terminal 802 and the negative terminal 803, which are respectively matched with the positive terminal boss 7011 and the negative terminal boss 7021. Finally, the positive terminal boss 7011 and the positive terminal 802, the negative terminal boss 7021 and the negative terminal 803, and the two end faces of the substrate 801 and the shell 90 are respectively welded together by laser. This completes the parallel assembly of the eight cells.

[0100] The difference between Embodiment 4 of the present invention and Embodiments 1, 2 and 3 is that Embodiments 1, 2 and 3 are all for a four-cell parallel connection scheme, while Embodiment 4 is for an eight-cell parallel connection scheme.

[0101] It should be noted that the first single cell 30 and the second single cell 40 in Embodiments 1, 2, 3 and 4 of the present invention are all stacked cells, but Embodiments 1, 2 and 4 can also use wound cells.

[0102] It should be noted that, compared with traditional cell assembly methods, in this invention, all tabs of each parallel cell are in a stretched state, avoiding "S"-shaped bending and reducing the risk of short circuits caused by tab insertion. Furthermore, this invention reduces the risk of poor welding and welding tearing caused by excessive tab layers in traditional multi-cell parallel schemes. Since there is a large gap between the multi-layer tabs and the cover plate in the prior art, it will reduce the energy density of the single lithium battery. In contrast, the cells of this invention are more compact, reducing the space occupied by the tabs and improving the energy density of the lithium battery.

[0103] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects: On the one hand, by pairing the first single cell with the second single cell and completing the interconnection of the electrodes inside the cell (i.e., directly welding the first positive electrode to the second positive electrode and the first negative electrode to the second negative electrode), and using additional external positive and external negative electrodes, with the external positive electrode bent and attached to the side of the positive electrode guide that is away from the first cell body, and the external negative electrode bent and attached to the side of the negative electrode guide that is away from the second cell body, not only can the number of welding operations on the same electrode be reduced, but also the fact that the external positive electrode is only welded to the positive electrode guide and the external negative electrode is only welded to the negative electrode guide can reduce the thickness of the welding interface, so that the laser or ultrasonic welding energy can be evenly transmitted to each contact surface, thereby eliminating the outer electrode... The defects of torn tabs and poor inner layer soldering are significantly improved, thus significantly increasing the reliability and yield of electrical connections. This solves the problem of uneven ultrasonic energy distribution caused by re-welding the positive and negative leads after the multi-layer tabs are paired and welded in traditional processes. At the same time, by directly stacking multiple first and second single cells along the thickness direction Z of the stack to form a stacked core unit, and bending and attaching the external positive tab to the side of the positive lead that is away from the first cell body, and bending and attaching the external negative tab to the side of the negative lead that is away from the second cell body, the traditional long tab and S-shaped bending core structure can be eliminated. Furthermore, the positive lead separates the external positive tab from the first cell body, and the negative lead separates the external negative tab from the second cell body, thus avoiding the risk of the tabs being inserted into the cell and eliminating the risk of short circuits.

[0104] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A stacked core assembly, characterized in that, include: The stacked core unit includes a stacked core (100), the stacked core (100) includes a plurality of first single cells (30) and a plurality of second single cells (40) stacked along the thickness direction (Z) of the stacked core (100). The plurality of first single cells (30) and the plurality of second single cells (40) are arranged in a one-to-one correspondence. The first single cell (30) includes a first cell body (31), a first positive electrode (32), a first negative electrode (33) and an external positive electrode (34). The second single cell (40) includes a second cell body (41), a second positive electrode (42), a second negative electrode (43) and an external negative electrode (44). The first negative electrode (33) is electrically connected to the corresponding second negative electrode (43), and the first positive electrode (32) is electrically connected to the corresponding second positive electrode (42). A positive electrode guide (701) and a negative electrode guide (702) are provided. The positive electrode guide (701) is located between the two sides of the stacked core unit in the thickness direction (Z). The negative electrode guide (702) is located between the two sides of the stacked core unit in the thickness direction (Z). The external positive electrode tabs (34) of a plurality of first single cells (30) are bent and attached to the side of the positive electrode guide (701) away from the first cell body (31). The external negative electrode tabs (44) of a plurality of second single cells (40) are bent and attached to the side of the negative electrode guide (702) away from the second cell body (41), so that the plurality of first single cells (30) and the plurality of second single cells (40) are arranged in parallel.

2. The stacked core assembly according to claim 1, characterized in that, In the width direction (X) of the stacked core (100), the stacked core (100) has a first side and a second side arranged opposite to each other. A plurality of external positive electrodes (34) and a plurality of external negative electrodes (44) are located on the first side. A plurality of first positive electrodes (32), a plurality of first negative electrodes (33), a plurality of second positive electrodes (42) and a plurality of second negative electrodes (43) are located on the second side. The first positive electrodes (32) and the first negative electrodes (33) are spaced apart in the length direction (Y) of the stacked core (100). The second positive electrodes (42) and the second negative electrodes (43) are spaced apart in the length direction (Y) of the stacked core (100).

3. The stacked core assembly according to claim 2, characterized in that, The stacked core (100) further includes a plurality of positive connectors (501), each of which is corresponding to a plurality of first positive tabs (32). The first positive tabs (32) and the second positive tabs (42) are both welded to the corresponding positive connectors (501) to form a positive connection structure. The stacked core (100) further includes a plurality of negative connectors (502), each of which is corresponding to a plurality of first negative tabs (33). The first negative tabs (33) and the second negative tabs (43) are both welded to the corresponding negative connectors (502) to form a negative connection structure.

4. The stacked core assembly according to claim 3, characterized in that, The stacked core (100) also includes insulating tape (60), and the positive connection structure is wrapped with the insulating tape (60) on both sides of its thickness direction (Z). The positive connection structure and the insulating tape (60) on both sides can be bent. The negative connection structure is wrapped with insulating tape (60) on both sides of its thickness direction (Z), and both the negative connection structure and the insulating tape (60) on both sides can be bent.

5. The stacked core assembly according to claim 2, characterized in that, The positive electrode guide (701) includes a positive electrode boss (7011) and a positive electrode guide substrate (7012) connected to the positive electrode boss (7011). The positive electrode guide substrate (7012) is attached to the stacked core (100), and a plurality of external positive electrode tabs (34) are bent and attached to the side of the positive electrode guide substrate (7012) away from the first cell body (31). The negative electrode guide (702) includes a negative electrode boss (7021) and a negative electrode guide substrate (7022) connected to the negative electrode boss (7021). The negative electrode guide substrate (7022) is attached to the stacked core (100), and a plurality of external negative electrode ears (44) are bent and attached to the side of the negative electrode guide substrate (7022) away from the second cell body (41).

6. The stacked core assembly according to claim 5, characterized in that, The stacked core (100) includes two first single cells (30) and two second single cells (40), which are stacked sequentially along the thickness direction (Z); The positive electrode drainage substrate (7012) includes a positive electrode drainage plate (7014), which is located between two external positive electrode tabs (34), and the two external positive electrode tabs (34) are bent and attached to the positive electrode drainage plate (7014); the negative electrode drainage substrate (7022) includes a negative electrode drainage plate, which is located between two external negative electrode tabs (44), and the two external negative electrode tabs (44) are bent and attached to the negative electrode drainage plate.

7. The stacked core assembly according to claim 5, characterized in that, The stacked core (100) includes two first single cells (30) and two second single cells (40), with the two second single cells (40) located between the two first single cells (30); The positive electrode drainage substrate (7012) includes a connecting plate (7013) and two positive electrode drainage plates (7014). The connecting plate (7013) is provided with the positive electrode boss (7011). The two positive electrode drainage plates (7014) are respectively connected to the two ends of the connecting plate (7013). The two external negative electrode ears (44) are located between the two positive electrode drainage plates (7014) and between the two external positive electrode ears (34). The two external positive electrode ears (34) are respectively bent and attached to the two positive electrode drainage plates (7014). The negative electrode drainage substrate (7022) includes a negative electrode drainage plate. The negative electrode drainage plate is located between the two external negative electrode ears (44). The two external negative electrode ears (44) are bent and attached to the negative electrode drainage plate.

8. The stacked core assembly according to claim 7, characterized in that, The stacked core unit includes two stacked cores (100), which are arranged side by side in the width direction (X) of the stacked cores (100), and the second sides of the two stacked cores (100) are arranged facing each other. The stacked core unit has a third side and a fourth side arranged opposite to each other in the length direction (Y) of the stacked cores (100). The positive electrode drain component (701) includes two positive electrode drain substrates (7012), two connecting plates (7013) connected together and located on the third side, and a positive electrode boss (7011) disposed on at least one of the two connecting plates (7013). The two positive electrode drain plates (7014) connected to one of the two connecting plates (7013) are bent and electrically connected to the two external positive electrode ears (34) of one of the two stacked cores (100). The two positive electrode drain plates (7014) connected to the other connecting plate (7013) are bent and electrically connected to the two external positive electrode ears (34) of the other stacked core (100). The negative electrode draining component (702) includes two connected negative electrode draining substrates (7022), and a negative electrode boss (7021) is disposed on at least one of the two negative electrode draining substrates (7022). The negative electrode boss (7021) is located on the fourth side. One of the two negative electrode draining plates is bent and electrically connected to the two external negative electrode ears (44) of one of the two stacked cores (100). The other of the two negative electrode draining plates is bent and electrically connected to the two external negative electrode ears (44) of the other stacked core (100).

9. A lithium battery, characterized in that, The device includes a housing (90), at least one cover plate assembly (80), and a core assembly according to any one of claims 1 to 8, the core assembly being disposed within the housing (90), and the cover plate assembly (80) covering the housing (90).

10. A method for assembling a stacked core assembly, characterized in that, The assembly method of the stacked core assembly is used to assemble the stacked core assembly according to any one of claims 1 to 8.

11. The assembly method of the stacked core assembly according to claim 10, characterized in that, The assembly method of the stacked core assembly includes: Step S10: Prepare the first single cell (30) and the second single cell (40) arranged in parallel, wherein the first positive electrode (32) of the first single cell (30) is electrically connected to the second positive electrode (42) of the second single cell (40), and the first negative electrode (33) of the first single cell (30) is electrically connected to the second negative electrode (43) of the second single cell (40); Step S20: Repeat step S10 multiple times to prepare multiple dual-cell structures, wherein the dual-cell structure includes the first single cell (30) and the second single cell (40) arranged in parallel. Step S30: Stack a plurality of first single cells (30) and a plurality of second single cells (40) along the thickness direction (Z) of the stacked core (100) to form the stacked core (100). Step 40: Bend and attach the external positive tabs (34) of the plurality of first single cells (30) to the side of the positive lead-in component (701) away from the first cell body (31), and bend and attach the external negative tabs (44) of the plurality of second single cells (40) to the side of the negative lead-in component (702) away from the second cell body (41), so that the plurality of first single cells (30) and the plurality of second single cells (40) are connected in parallel.

12. The assembly method of the stacked core assembly according to claim 11, characterized in that, Step S10 includes: Step S11: Stack a positive electrode plate (10) with an external positive electrode tab (34) and a first positive electrode tab (32), a separator, and a negative electrode plate (20) with a first negative electrode tab (33) to form the first single cell (30). Step S12: Stack the negative electrode plate (20) with external negative electrode tab (44) and second negative electrode tab (43), the separator and the positive electrode plate (10) with second positive electrode tab (42) to form the second single cell (40). Step S13: Weld the first positive tab (32) of the first single cell (30) to the second positive tab (42) of the second single cell (40) through a positive connector (501), and weld the first negative tab (33) of the first single cell (30) to the second negative tab (43) of the second single cell (40) through a negative connector (502).

13. The assembly method of the stacked core assembly according to claim 11, characterized in that, Step S10 includes: Step 14: Prepare a positive electrode sheet (10), the positive electrode sheet (10) includes an external positive electrode tab (34), two small positive electrode sheets and an extended positive electrode tab for connecting the two small positive electrode sheets, and the external positive electrode tab (34) is provided on one of the two small positive electrode sheets. Step 15: Prepare a negative electrode sheet (20), the negative electrode sheet (20) includes an external negative electrode tab (44), two negative electrode small pieces and an extended negative electrode tab for connecting the two negative electrode small pieces, and the external negative electrode tab (44) is provided on one of the two negative electrode small pieces. Step 16: Stack the positive electrode (10), the separator and the negative electrode (20) to form the first single cell (30) and the second single cell (40) connected in parallel.

14. The assembly method of the stacked core assembly according to claim 11, characterized in that, The dual-cell structure comprises two cells, and step S30 includes: The two dual-cell structures are arranged in a cross pattern; Fold three of the two first single cells (30) and two second single cells (40) over and stack them on the remaining one of the two first single cells (30) and two second single cells (40) to form the stacked core (100).

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