A high capacity battery and a method of manufacturing the same

Abstract

The application provides a high-capacity battery and a preparation method thereof. The high-capacity battery comprises a shell, a cover plate assembly, a first connecting sheet, a second connecting sheet and a battery module. The battery module comprises at least two stacked cores and is sequentially stacked in the inner cavity of the shell. The stacked core is provided with a first switching assembly and a second switching assembly. The first switching assemblies of two adjacent stacked cores are connected in parallel through the first connecting sheet, and the second switching assemblies of two adjacent stacked cores are connected in parallel through the second connecting sheet. The first connecting sheet and the second connecting sheet independently comprise a connecting body. The connecting body has opposite first and second surfaces. The two ends of the connecting body are bent to the side of the second surface to form a first bent part and a second bent part. The first bent part and the second bent part are connected to the first switching assembly or the second switching assembly of two adjacent stacked cores, respectively. The application alleviates the battery polarization problem, simplifies the battery manufacturing method, and greatly increases the battery capacity.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of batteries, and relates to a high-capacity battery and a preparation method thereof. BACKGROUND

[0002] A large-capacity single battery can greatly improve the energy density of an energy storage system and is one of the important trends for future development of the energy storage system. The use of a large-capacity single battery can improve the degree of simplification of integrated assembly process, reduce the number of parallel connections, and reduce the difficulty of BMS, thereby greatly saving the investment in land infrastructure, container, and other costs, and further reducing the production cost.

[0003] However, the increase in battery capacity makes the size of the single battery larger and the process manufacturing difficulty greater. Traditional batteries have two tab structures. With the development requirements, higher energy density batteries are needed, and the single battery gradually adopts the lamination method. Correspondingly, the full tab design and the multi-stage tab design have become the main development direction. The assembly and welding process of the full tab scheme is simpler, but since the positive and negative tabs are at both ends of the cell, two cover plates are usually needed, the welding process is complex, and the PACK assembly process is cumbersome. The existing side-out structure scheme usually uses an L-shaped current collector, but there is a problem that the residual heat of the welding between the main body and the tab is easy to burn the core package, which causes the positive and negative tabs to be short-circuited, causing internal short circuit of the battery, and in severe cases, it may cause the battery to catch fire. In addition, the battery polarization of the side-out structure is serious, which makes the battery front cycle climbing data poor.

[0004] Therefore, it is very important to provide a battery structure that is convenient to process, has a reasonable tab design, and has excellent overall electrical performance. SUMMARY

[0005] In view of the deficiencies in the prior art, the purpose of the present application is to provide a high-capacity battery and a preparation method thereof, which alleviates the battery polarization problem and also simplifies the battery manufacturing method, greatly increasing the battery capacity.

[0006] To achieve this purpose, the present application adopts the following technical solutions:

[0007] In a first aspect, the present invention provides a high-capacity battery, the high-capacity battery comprising a housing, a cover plate assembly, a first connecting piece, a second connecting piece, and a battery module; the battery module comprises at least two stacked cores, the at least two stacked cores being sequentially stacked within the cavity of the housing; an opening is provided at the top of the housing, and the cover plate assembly is disposed at the opening; each stacked core is provided with a first adapter assembly and a second adapter assembly, the first adapter assemblies of two adjacent stacked cores being connected in parallel via the first connecting piece, and the second adapter assemblies of two adjacent stacked cores being connected in parallel via the second connecting piece; the first connecting piece and the second connecting piece independently comprise a connecting body, the connecting body having a first surface and a second surface opposite to each other, the first surface being connected to the cover plate assembly, and the second surface being close to the stacked core; both ends of the connecting body are bent toward the second surface to form a first bent portion and a second bent portion, the first bent portion and the second bent portion of the first connecting piece being respectively connected to the first adapter assemblies of two adjacent stacked cores, and the first bent portion and the second bent portion of the second connecting piece being respectively connected to the second adapter assemblies of two adjacent stacked cores.

[0008] The high-capacity battery of this invention adopts a flexible and foldable connecting piece design to connect the positive or negative electrodes of the stacked cell structure in parallel. The connecting piece can be changed into different bending states according to different needs to meet assembly and production requirements. It also helps to reduce the transfer height, reduce cell cost, optimize battery weight, improve the utilization rate of internal space of the casing, and has high flow capacity, effectively improving battery capacity.

[0009] As a preferred embodiment of the present invention, the first bending portion and the second bending portion each have a first side surface and a second side surface that are opposite to each other; the first side surface of the first bending portion is attached to the connecting body, and the second side surface of the first bending portion is connected to the first adapter component or the second adapter component; the first side surface of the second bending portion is attached to the connecting body, and the second side surface of the second bending portion is connected to the first adapter component or the second adapter component.

[0010] It should be noted that both the first bending portion and the second bending portion in this invention are bent from the plane of the connecting body toward one side of its second surface, and the first bending portion and the second bending portion are arranged opposite to each other. Those skilled in the art can adjust the bending angle according to the actual situation.

[0011] As a preferred embodiment of the present invention, the stacked core includes a first battery cell group and a second battery cell group stacked sequentially. The first battery cell group has a first positive electrode tab and a first negative electrode tab that converge in a first direction at one end near the cover plate assembly. The second battery cell group has a second positive electrode tab and a second negative electrode tab that converge in a second direction at one end near the cover plate assembly. The first direction is opposite to the second direction. The first positive electrode tab is U-shaped, and the second positive electrode tab is S-shaped, and they are independently connected to the first connecting piece to form the first adapter assembly. The first negative electrode tab is U-shaped, and the second negative electrode tab is S-shaped, and they are independently connected to the second connecting piece to form the second adapter assembly.

[0012] It should be noted that the first and second battery cell groups in this invention are each composed of multiple individual battery cells stacked sequentially, and the positive and negative electrode tabs of each individual battery cell are both stacked structures, extending from one side of the individual battery cell. Multiple stacked positive electrode tabs converge along a first or second direction to form a positive electrode tab portion, and multiple stacked negative electrode tabs converge along a first or second direction to form a negative electrode tab portion.

[0013] The battery module of this invention has a battery structure with at least four cells, employing a top-mounted multi-tab stacked configuration to alleviate battery polarization issues and facilitate cell turnover. The tabs of the first and second cell groups converge in opposite directions, resulting in a back-to-back design between the first and second positive tabs after convergence, and a back-to-back design between the first and second negative tabs after convergence. This optimizes the tab height, ensuring consistent tab height throughout the battery module and a compact structure. The initial state of each tab after convergence is a multi-layered stacked structure. After connecting to the first or second connecting piece, the tabs converged along the first direction bend into a "U" shape, and the tabs converged along the second direction bend into an "S" shape. Compared to traditional battery structures, this invention reduces tab height, improves internal space utilization, reduces material consumption, and saves manufacturing costs.

[0014] As a preferred embodiment of the present invention, the cover plate assembly includes a top cover body, on which a first battery cell terminal and a second battery cell terminal are disposed. The first battery cell terminal is located inside the housing and is connected to the first connecting piece, and the second battery cell terminal is located inside the housing and is connected to the second connecting piece.

[0015] An insulating layer is provided on the surface of the top cover body near the inner cavity of the housing, and the insulating layer extends toward the inner cavity of the housing; a gap is left between the insulating layer and the outer edge of the connecting body.

[0016] The insulating layer in this invention is used to insulate the top cover assembly from the battery cell inside the housing, thus preventing battery short circuits.

[0017] It should be noted that the outer edge of the connecting body in this invention refers to the folded edge formed by bending the two ends of the connecting body.

[0018] In a preferred embodiment of the present invention, the height of the first and second battery cell terminals within the housing is greater than the height of the insulating layer. A receiving protrusion is provided on the second surface of the connecting body, protruding towards the inner cavity of the housing. The end of the first battery cell terminal extending beyond the insulating layer is located within the receiving protrusion of the first connecting piece; the end of the second battery cell terminal extending beyond the insulating layer is located within the receiving protrusion of the second connecting piece.

[0019] The connecting piece of the present invention has a concave-convex structure. The first surface of the connecting body is recessed towards the inner cavity of the shell to form a hollow receiving protrusion, which plays a positioning role in the manufacturing process and also reserves more usable space for the inner cavity of the shell.

[0020] In the first or second direction, the linear distance between the insulating layer and the outer edge of the connecting body is 1 to 2 mm, for example, it can be 1 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm or 2 mm, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0021] The insulating layer also has clearance openings.

[0022] After the cover plate assembly is connected and fixed to the first connecting piece and the second connecting piece respectively, the present invention uses a pressure application mechanism commonly used by those skilled in the art to bend the first connecting piece and the second connecting piece through the clearance opening.

[0023] As a preferred embodiment of the present invention, the surface of the connecting body is provided with two thinning grooves, and bending along the two thinning grooves respectively forms the first bending portion and the second bending portion.

[0024] The first connecting piece and the second connecting piece of the present invention have a flat plate structure, which facilitates material transportation and loading operations. During the subsequent preparation process, they are bent along the reserved thinning groove, which improves the bending yield.

[0025] The width of the thinning groove is 3 to 4 mm, for example, it can be 3 mm, 3.1 mm, 3.2 mm, 3.3 mm, 3.4 mm, 3.5 mm, 3.6 mm, 3.7 mm, 3.8 mm, 3.9 mm or 4 mm, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0026] The depth of the thinning groove is 0.2 to 0.5 mm, for example, it can be 0.2 mm, 0.22 mm, 0.25 mm, 0.26 mm, 0.28 mm, 0.3 mm, 0.35 mm, 0.38 mm, 0.4 mm, 0.44 mm, 0.45 mm, 0.48 mm or 0.5 mm, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0027] The connecting body has two opposing arc-shaped openings on both sides.

[0028] A foolproof angle is provided along the outer edge of the receiving convex hull.

[0029] In this invention, arc-shaped openings are provided on the two non-bent sides of the connecting body to avoid interference with the battery filling port.

[0030] As a preferred embodiment of the present invention, a support plate is also provided at the bottom of the inner cavity of the housing.

[0031] The inner cavity sidewall of the housing is also provided with a protective layer, which surrounds the outer periphery of the battery module, and the two ends of the protective layer are respectively connected to the insulating layer and the support plate.

[0032] This invention uses an insulating layer, a protective layer, and a support bracket to cover and insulate the battery module, avoiding direct contact between the battery cell and the casing, which could cause a short circuit.

[0033] In a second aspect, the present invention provides a method for preparing the high-capacity battery described in the first aspect, the method comprising:

[0034] The first connecting piece is used to connect the first transition components of two adjacent stacked cores in parallel;

[0035] The second connecting piece is used to connect the second transition components of two adjacent stacked cores in parallel;

[0036] The first connecting piece and the second connecting piece are independently connected to the cover plate assembly, and then installed into the housing to obtain a high-capacity battery.

[0037] As a preferred embodiment of the present invention, the preparation method includes the following steps:

[0038] (1) Bend the first bending portion and the second bending portion of the first connecting piece and the second connecting piece once, so that the first bending portion and the second bending portion are independently perpendicular to the plane of the connecting body;

[0039] (2) The first positive electrode and the first negative electrode of the first battery cell group are brought together in the first direction, and the second positive electrode and the second negative electrode of the second battery cell group are brought together in the second direction. Then the first battery cell group and the second battery cell group are combined once to obtain stacked cores.

[0040] (3) Repeat step (2) to make two stacked cores, which are referred to as the first stacked core and the second stacked core respectively;

[0041] (4) The first positive electrode tab and the second positive electrode tab of the first stack core are respectively welded and fixed to the second side of the first bend of the first connecting piece, and the first negative electrode tab and the second negative electrode tab are welded and fixed to the second side of the first bend of the second connecting piece; the first positive electrode tab and the second positive electrode tab of the second stack core are welded and fixed to the second side of the second bend of the first connecting piece, and the first negative electrode tab and the second negative electrode tab are welded and fixed to the second side of the second bend of the second connecting piece;

[0042] (5) Fold the first stack of cores and the second stack of cores in a direction away from each other, and weld and fix the cover plate assembly so that the cover plate assembly is connected to the first connecting piece and the second connecting piece respectively;

[0043] (6) The first and second bending portions of the first connecting piece and the second connecting piece are bent twice, so that the first side of the first bending portion and the second bending portion fits into the main body, realizing the second core of the first stack and the second stack, and then it is installed into the housing to obtain a high-capacity battery.

[0044] The present invention provides a convenient preparation method that avoids the problem of residual heat burns during welding of connecting pieces, reduces the loss of raw materials, simplifies the overall manufacturing process, and ensures the space utilization rate of the battery cavity.

[0045] As a preferred embodiment of the present invention, the secondary bending includes: pressing the first bending portion or the second bending portion with a folding knife, so that the first bending portion or the second bending portion bends toward the side closer to the second surface of the connecting body, until it fits against the connecting body.

[0046] The thickness of the folding knife is 2 to 3 mm, for example, it can be 2 mm, 2.1 mm, 2.2 mm, 2.3 mm, 2.4 mm, 2.5 mm, 2.6 mm, 2.7 mm, 2.8 mm, 2.9 mm or 3 mm, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0047] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0048] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0049] This invention provides a high-capacity battery and its preparation method. It adopts a flexible and foldable connecting piece design, which reduces the height of the adapter tabs, lowers the cost of the battery cell, and improves the utilization rate of the casing space. By ejecting a multi-tab stacked structure, it reduces tab polarization and effectively increases the battery capacity, resulting in a battery capacity of up to 630Ah. Attached Figure Description

[0050] Figure 1 A schematic diagram of the external structure of a high-capacity battery provided in a specific embodiment of the present invention;

[0051] Figure 2 An exploded view of a high-capacity battery provided for a specific embodiment of the present invention;

[0052] Figure 2 (a) is Figure 2 Bottom view of the cover plate assembly;

[0053] Figure 3 A schematic diagram of the structure of the first connecting piece in its "initial state" provided for a specific embodiment of the present invention;

[0054] Figure 3 (a) is a side view of the first connecting piece in its "initial state";

[0055] Figure 3 (b) is Figure 3 (a) A magnified view of point A in the image;

[0056] Figure 4 A schematic diagram of the structure of the first connecting piece in an "intermediate state" provided for a specific embodiment of the present invention;

[0057] Figure 4 (a) is a side view of the first connecting piece in the "intermediate state";

[0058] Figure 5 A schematic diagram of the structure of the first connecting piece in a "completed state" provided for a specific embodiment of the present invention;

[0059] Figure 5 (a) is a side view of the first connecting piece in the "completed state";

[0060] Figure 6This is a schematic diagram of the structure of a battery module provided in a specific embodiment of the present invention;

[0061] Figure 7 A schematic diagram showing the first positive electrode tab and the second positive electrode tab after being closed, according to a specific embodiment of the present invention;

[0062] Figure 8 A schematic diagram showing the connection of the first positive electrode tab and the second positive electrode tab to the first connecting piece, according to a specific embodiment of the present invention;

[0063] Figure 8 (a) is Figure 8 A magnified view of a section at point B in the middle;

[0064] Figure 9 A schematic diagram of the positive and negative tabs of a single battery cell before it is collapsed, provided as a specific embodiment of the present invention;

[0065] Figure 10 A schematic diagram of the positive electrode tab of a single battery cell before it is collapsed, provided as a specific embodiment of the present invention;

[0066] Figure 11 A schematic diagram of the first positive electrode ear after being folded up, provided for a specific embodiment of the present invention;

[0067] Figure 12 A schematic diagram of the structure of a cover plate assembly provided in a specific embodiment of the present invention;

[0068] Figure 13 This is a schematic diagram illustrating the parallel connection of a first core stack and a second core stack during the battery manufacturing process, provided as a specific embodiment of the present invention.

[0069] Figure 13 (a) A side view of a battery manufacturing process in which a first connecting piece and a second connecting piece are used to connect a first stack of cores and a second stack of cores in parallel, according to a specific embodiment of the present invention;

[0070] Figure 14 This is a schematic diagram illustrating the folding of the first and second stacks of cores during the battery manufacturing process, according to a specific embodiment of the present invention.

[0071] Figure 15 This is a schematic diagram of the battery manufacturing process after welding the cover plate assembly, as provided in a specific embodiment of the present invention.

[0072] Figure 16 This is a schematic diagram of the welding of the cover plate assembly during the battery manufacturing process, provided as a specific embodiment of the present invention.

[0073] Figure 17A schematic diagram of the battery manufacturing process after secondary core assembly is provided for a specific embodiment of the present invention;

[0074] Figure 18 A schematic diagram of a first pre-welding area provided for a specific embodiment of the present invention;

[0075] Figure 19 A schematic diagram of the second pre-welding area provided in a specific embodiment of the present invention;

[0076] Figure 20 This is a schematic diagram of a secondary bending process provided for a specific embodiment of the present invention.

[0077] Wherein, 1-first connecting piece; 2-cover plate assembly; 21-avoidance opening; 22-first cell terminal post; 3-first stacked core; 4-second stacked core; 31-first positive electrode tab; 32-first negative electrode tab; 41-second positive electrode tab; 42-second negative electrode tab; 5-protective layer; 6-supporting bracket; 7-shell; 8-folding blade; 9-second connecting piece; 10-insulating layer; 12-connecting body; 112-accommodating protrusion; 113-anti-foolproof angle; 114-arc-shaped opening; 115-thinning groove; 121-first bending part; 131-second bending part; 100-first cell group; 200-second cell group; 300-third cell group; 400-fourth cell group; A1, A2-positive electrode tab; B1, B2-negative electrode tab; S1-first pre-soldering area; S2-second pre-soldering area. Detailed Implementation

[0078] It should be understood that in the description of this invention, the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are used only for the convenience of describing the invention and for simplifying the description, 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 the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0079] It should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "set," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; 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; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0080] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0081] In one specific embodiment, the present invention provides a high-capacity battery, such as... Figure 1 , Figure 2 and Figure 2 As shown in (a), the device includes a housing 7, a cover plate assembly 2, a first connecting piece 1, a second connecting piece 9, and a battery module. The battery module includes at least two stacked cores, which are sequentially stacked within the cavity of the housing 7. Each stacked core is equipped with a first adapter assembly and a second adapter assembly. The first adapter assemblies of two adjacent stacked cores are connected in parallel via the first connecting piece 1, and the second adapter assemblies of two adjacent stacked cores are connected in parallel via the second connecting piece 9. Figure 3 , Figure 4 and Figure 5 As shown, the first connecting piece 1 and the second connecting piece 9 independently include a connecting body 12. The connecting body 12 has a first surface and a second surface facing each other. The first surface is connected to the cover plate assembly 2, and the second surface is close to the stacked cores. Both ends of the connecting body 12 are bent toward the second surface to form a first bent portion 121 and a second bent portion 131. The first bent portion and the second bent portion of the first connecting piece 1 are respectively connected to the first transition assemblies of two adjacent stacked cores, and the first bent portion and the second bent portion of the second connecting piece 9 are respectively connected to the second transition assemblies of two adjacent stacked cores.

[0082] The first and second adapter components, as well as the third and fourth adapter components, are all top-out structures. The first connecting piece 1 is used for parallel connection of the positive electrode adapter components of two adjacent stacked cores, and the second connecting piece 9 is used for parallel connection of the negative electrode adapter components of two adjacent stacked cores. Both the first connecting piece 1 and the second connecting piece 9 have a certain degree of flexibility and low hardness, allowing them to be folded. The tensile strength of the first connecting piece 1 is 60–150 MPa, and its Vickers hardness is 20–35 HV. It has good elongation and can meet the requirements of various pressure processing, stretching, and bending. The Vickers hardness of the second connecting piece 9 is ≤70 HV, and it has high flow capacity, plasticity, and ductility. Furthermore, the thickness of the first connecting piece 1 is greater than the thickness of the second connecting piece 9. The material of the first connecting piece 1 can be aluminum, such as 1060-O state aluminum, which is well known to those skilled in the art. The material of the second connecting piece 9 can be copper, such as T2-M copper, which is well known to those skilled in the art. When the raw material has high hardness, it can be annealed to meet the required softness.

[0083] In some implementations, such as Figure 4 and Figure 5 As shown, the first bending portion 121 and the second bending portion 131 each have an independent first side and a second side. The first side of the first bending portion 121 is attached to the connecting body 12, and the second side of the first bending portion 121 is connected to the first adapter assembly or the second adapter assembly. The first side of the second bending portion 131 is attached to the connecting body 12, and the second side of the second bending portion 131 is connected to the first adapter assembly or the second adapter assembly. During the battery manufacturing process, those skilled in the art can adjust the bending angles of the first bending portion 121 and the second bending portion 131 according to different manufacturing steps. For example, as... Figure 4 As shown, when both the first bending portion 121 and the second bending portion 131 are bent at 90°, both the first bending portion 121 and the second bending portion 131 are perpendicular to the plane where the connecting body 12 is located, and the first bending portion 121 and the second bending portion 131 are parallel to each other; Figure 5 As shown, when both the first bending portion 121 and the second bending portion 131 are bent at 180°, the first side surfaces of the first bending portion 121 and the second bending portion 131 are attached to the main body 12, and the first bending portion 121 and the second bending portion 131 extend in opposite directions respectively.

[0084] In some implementations, such as Figure 3 , Figure 3 (a) and Figure 3As shown in (b), the surface of the connecting body 12 is provided with two thinning grooves 115. Bending along the two thinning grooves 115 respectively forms the first bending portion 121 and the second bending portion 131. Specifically, the width of the thinning groove 115 is 3-4 mm, and the depth of the thinning groove 115 is 0.2-0.5 mm. The first connecting piece 1 and the second connecting piece 9 of the present invention have a flat plate structure, and bending along the reserved thinning grooves 115 facilitates automated operation and improves the bending yield. Figure 4 (a) and Figure 5 (a) Depending on the different manufacturing stages, the first connecting piece 1 and the second connecting piece 9 can be divided into an "initial state," an "intermediate state," and a "completed state." The "initial state" refers to the unbent, flat state for material loading; the "intermediate state" refers to the state where the two ends of the connecting body 12 are bent at 90° by two thinning grooves 115, i.e., the first bent portion and the second bent portion 131 are parallel to each other and perpendicular to the connecting body 12; the "completed state" refers to the state where the two ends of the connecting body 12 are bent at 180° by two thinning grooves 115, i.e., the first side surfaces of the first bent portion 121 and the second bent portion 131 are attached to the second surface of the connecting body 12. Furthermore, two opposing arc-shaped openings 114 are provided on both sides of the connecting body 12 to avoid interference with the battery filling port.

[0085] In some embodiments, the stacked core includes a first cell group and a second cell group stacked sequentially. The first cell group has a first positive electrode tab and a first negative electrode tab that converge in a first direction at one end near the cover plate assembly. The second cell group has a second positive electrode tab and a second negative electrode tab that converge in a second direction at one end near the cover plate assembly, where the first direction is opposite to the second direction. The first positive electrode tab is U-shaped, and the second positive electrode tab is S-shaped, and both are independently connected to the first connecting piece to form the first adapter assembly. Similarly, the first negative electrode tab is U-shaped, and the second negative electrode tab is S-shaped, and both are independently connected to the second connecting piece to form the second adapter assembly.

[0086] Taking a battery module with two stacked cells as an example, denoted as the first stacked cell 3 and the second stacked cell 4 respectively. Figure 6 As shown, the first stacked core 3 includes a first cell group 100 and a second cell group 200 stacked in sequence, and the second stacked core 4 includes a third cell group 300 and a fourth cell group 400 stacked in sequence.

[0087] The first cell assembly 100 has a first positive electrode tab 31 and a first negative electrode tab 32 that converge in a first direction at one end near the cover plate assembly 2. The first cell assembly 100 is composed of a plurality of stacked cell units, and the top of each cell unit leads out a stacked positive electrode tab A1 and a stacked negative electrode tab B1, as shown below. Figure 7 As shown, several stacked positive electrode tabs A1 are gathered together along the first direction and welded to the same side to form a first positive electrode tab 31 with an initial conical folded shape. Several stacked negative electrode tabs B1 are gathered together along the first direction and welded to the same side to form a first negative electrode tab 32 with an initial conical folded shape. The second cell assembly 200 is provided with a second positive electrode tab 41 and a second negative electrode tab 42 gathered together along the second direction at one end near the cover plate assembly 2. The second cell assembly 200 consists of several stacked cell units. A stacked positive electrode tab A2 and a stacked negative electrode tab B2 are led out from the top of each cell unit. Several stacked positive electrode tabs A2 are brought together along a second direction and soldered to the same side, forming a second positive electrode tab 41 that is initially conical and folded. Several stacked negative electrode tabs B2 are brought together along the second direction and soldered to the same side, forming a second negative electrode tab 42 that is initially conical and folded. The first direction is opposite to the second direction. After being brought together, the first positive electrode tab 31 and the second positive electrode tab 41 in their initial state form a spaced-apart back-to-back structure, and the first negative electrode tab 32 and the second negative electrode tab 42 in their initial state form a spaced-apart back-to-back structure. After the first positive electrode tab 31 and the second positive electrode tab 41 are independently connected to the first bent portion 121 of the first connecting piece 1, as shown... Figure 8 and Figure 8 As shown in (a), the first positive electrode tab 31 is U-shaped and the second positive electrode tab 41 is S-shaped, forming the first adapter assembly. After the first negative electrode tab 32 and the second negative electrode tab 42 are independently connected to the first bent portion 121 of the second connecting piece 9, the first negative electrode tab 32 is U-shaped and the second negative electrode tab 42 is S-shaped, forming the second adapter assembly.

[0088] The third cell assembly 300 has a third positive electrode tab and a third negative electrode tab that converge in a first direction at one end near the cover plate assembly 2. The third cell assembly 300 is composed of several stacked cell units. A stacked positive electrode tab A1 and a stacked negative electrode tab B1 are led out from the top of each cell unit. Several stacked positive electrode tabs A1 converge in the first direction and are welded to the same side, forming a third positive electrode tab that is initially conical and folded. Several stacked negative electrode tabs B1 converge in the first direction and are welded to the same side, forming a third negative electrode tab that is initially conical and folded. The fourth cell assembly 400 has a fourth positive electrode tab and a fourth negative electrode tab that converge in a second direction at one end near the cover plate assembly 2. The fourth cell assembly 400 consists of several stacked cell units. A stacked positive electrode tab A2 and a stacked negative electrode tab B2 are led out from the top of each cell unit. The stacked positive electrode tabs A2 are brought together along a second direction and soldered to the same side, forming a fourth positive electrode tab that is initially conical and folded. Similarly, the stacked negative electrode tabs B2 are brought together along the second direction and soldered to the same side, forming a fourth negative electrode tab that is initially conical and folded. The first direction is opposite to the second direction. After being brought together, the third and fourth positive electrode tabs in their initial state form a spaced-out back-to-back structure, as do the third and fourth negative electrode tabs in their initial state. After the third positive electrode tab and the fourth positive electrode tab are independently connected to the second bent portion 131 of the first connecting piece 1, the third positive electrode tab is U-shaped and the fourth positive electrode tab is S-shaped, forming the third adapter assembly. After the third negative electrode tab and the fourth negative electrode tab are independently connected to the second bent portion 131 of the second connecting piece 9, the third negative electrode tab is U-shaped and the fourth negative electrode tab is S-shaped, forming the fourth adapter assembly.

[0089] Specifically, such as Figure 9 and Figure 10 As shown, before being folded up, the positive electrode tab A1 and negative electrode tab B1 of the first cell group 100, the second cell group 200, the third cell group 300, and the fourth cell group 400 are all the same size. The width d3 of both the positive electrode tab A1 and the negative electrode tab B1 is 40-45 mm, and the height d2 is 28-30 mm. Those skilled in the art can adjust the size of d3 according to the overcurrent value and determine the size of d2 based on the required tab length for assembly. Figure 11As shown, after being gathered together, the height h1 of the positive electrode tabs (first positive electrode tab 31, second positive electrode tab 41, third positive electrode tab, and fourth positive electrode tab) and the negative electrode tabs (first negative electrode tab 32, second negative electrode tab 42, third negative electrode tab, and fourth negative electrode tab) becomes 16-20mm, and the gathering value (the gathering value refers to the linear distance between the outer surface of the gathered tabs and the extended line of the outermost cell surface of the cell assembly) is 2.5-4mm, which meets the requirement that each stack of tabs can be welded and fixed. The height d1 of the cell is 190-195mm.

[0090] Furthermore, the first direction is the extension direction of the first bent portion 121 when it is in the state of being in contact with the main body 12, and the second direction is the extension direction of the second bent portion 131 when it is in the state of being in contact with the main body 12; the two are opposite.

[0091] In some implementations, such as Figure 6 and Figure 12 As shown, the cover assembly 2 includes a top cover body, on which a first battery cell terminal 22 and a second battery cell terminal are disposed. The first battery cell terminal 22 is partially located inside the housing 7 and connected to the first connecting piece 1. The second battery cell terminal is partially located inside the housing 7 and connected to the second connecting piece 9. An insulating layer 10 is provided on the surface of the top cover body near the inner cavity of the housing 7 to insulate the top cover assembly from the battery cell inside the housing 7. The insulating layer 10 extends towards the inner cavity of the housing 7, and a gap is left between the insulating layer 10 and the outer edge of the connecting body 12.

[0092] The height of the first cell terminal 22 and the second cell terminal within the housing 7 is greater than the height of the insulating layer 10. For example... Figures 3 to 5 As shown, the second surface of the connecting body 12 is provided with a receiving protrusion 112, which protrudes towards the inner cavity of the housing 7. The end of the first battery cell electrode 22 extending out of the insulating layer 10 is located within the receiving protrusion 112 of the first connecting piece 1; the end of the second battery cell electrode extending out of the insulating layer 10 is located within the receiving protrusion 112 of the second connecting piece 9. The first surfaces of the first connecting piece 1 and the second connecting piece 9 are recessed towards the inner cavity of the housing 7 to form a hollow receiving protrusion 112. The receiving protrusion 112 cooperates with the protruding portion of the bottom end face of the battery cell electrode on the cover plate assembly 2 to achieve the positioning and connection between the cover plate assembly 2 and the connecting piece. Furthermore, a foolproof angle 113 is provided along the outer edge of the receiving protrusion 112.

[0093] like Figure 12As shown, in the first or second direction, the distance x between the insulating layer 10 and the outer edge of the connecting body 12 is 1-2 mm. The insulating layer 10 also has a clearance opening 21, the width D of which is 15-18 mm. During battery manufacturing, after the cover plate assembly 2 is connected and fixed to the first connecting piece 1 and the second connecting piece 9, the first bent portion 121 and the second bent portion 131 of the connecting pieces need to be further bent. Therefore, a pressure mechanism commonly used by those skilled in the art is inserted through the clearance opening 21 to press the first bent portion 121 and the second bent portion 131 until the first side surfaces of the first bent portion 121 and the second bent portion 131 are attached to the connecting body 12.

[0094] In some implementations, such as Figure 2 As shown, a support plate 6 is also provided at the bottom of the inner cavity of the housing 7. The support plate 6 covers the bottom surface of the battery module to achieve insulation between the battery cell and the bottom of the housing 7. The present invention does not specifically limit the material of the support plate 6, and any insulating material commonly used in the art can be used, such as polypropylene or polyethylene terephthalate.

[0095] In some implementations, such as Figure 2 As shown, a protective layer 5 is also provided on the inner cavity sidewall of the housing 7. The protective layer 5 surrounds the outer periphery of the battery module, and the two ends of the protective layer 5 are respectively connected to the insulating layer 10 and the support piece 6. The support piece 6 of the present invention is connected to the bottom end of the protective layer 5 by hot-melt welding. The protective layer 5 covers the entire outer periphery of the battery module and is connected to the insulating layer 10 on the cover plate assembly 2 by hot-melt or adhesive bonding, and is tightened with tape to increase safety protection. The present invention does not specifically limit the material of the protective layer 5, and any insulating material commonly used in the art can be used, including but not limited to polyethylene terephthalate film or polypropylene film, preferably polyethylene terephthalate film.

[0096] In another specific embodiment, the present invention provides a method for preparing a high-capacity battery according to a specific embodiment, the method comprising:

[0097] S1: The first connecting piece is used to connect the first transition components of two adjacent stacked cores in parallel;

[0098] S2: Use the second connecting piece to connect the second transition components of two adjacent stacked cores in parallel;

[0099] S3: Connect the first connecting piece and the second connecting piece independently to the cover plate assembly, and then install them into the housing to obtain a high-capacity battery.

[0100] For example, when the number of stacked cells in the battery module is two, the preparation method specifically includes the following steps:

[0101] (1) The first bending portion 121 and the second bending portion 131 of the first connecting piece 1 and the second connecting piece 9 are bent once respectively, so that the first bending portion 121 and the second bending portion 131 are independently perpendicular to the plane where the connecting body 12 is located;

[0102] (2) The first positive electrode tab 31 and the first negative electrode tab 32 of the first cell group 100 are brought together in the first direction, and the second positive electrode tab 41 and the second negative electrode tab 42 of the second cell group 200 are brought together in the second direction; the third positive electrode tab and the third negative electrode tab of the third cell group 300 are brought together in the first direction, and the fourth positive electrode tab and the fourth negative electrode tab of the fourth cell group 400 are brought together in the second direction; then the first cell group 100 and the second cell group 200 are combined once to obtain the first stacked core 3, and the third cell group 300 and the fourth cell group 400 are combined once to obtain the second stacked core 4;

[0103] (3) Figure 13 As shown, the first positive electrode tab 31 and the second positive electrode tab 41 are welded and fixed to the second side of the first bent portion 121 of the first connecting piece 1, and the first negative electrode tab 32 and the second negative electrode tab 42 are welded and fixed to the second side of the first bent portion 121 of the second connecting piece 9; the third positive electrode tab and the fourth positive electrode tab are welded and fixed to the second side of the second bent portion 131 of the first connecting piece 1, and the third negative electrode tab and the fourth negative electrode tab are welded and fixed to the second side of the second bent portion 131 of the second connecting piece 9.

[0104] (4) Figure 14 , Figure 15 and Figure 16 As shown, the first stacked core 3 and the second stacked core 4 are folded in a direction away from each other, and the cover plate assembly 2 is welded and fixed, so that the cover plate assembly 2 is connected to the first connecting piece 1 and the second connecting piece 9 respectively.

[0105] (5) Figure 17 As shown, the first bending portion 121 and the second bending portion 131 of the first connecting piece 1 and the second connecting piece 9 are bent twice, so that the first side of the first bending portion 121 and the second bending portion 131 fits into the main body 12, realizing the second core merging of the first stacked core 3 and the second stacked core 4, and then it is installed into the housing 7 to obtain a high-capacity battery.

[0106] In step (1), the first connecting piece 1 and the second connecting piece 9 are connected as follows: Figure 3After loading the material in the "initial state" shown, and then bending it once along the two thinning grooves 115, both the first connecting piece 1 and the second connecting piece 9 are in the following position. Figure 4 The "intermediate state" shown.

[0107] In step (2), the first positive electrode tab 31, the first negative electrode tab 32, the second positive electrode tab 41, the second negative electrode tab 42, the third positive electrode tab, the third negative electrode tab, the fourth positive electrode tab, and the fourth negative electrode tab are welded and fixed respectively. Figure 13 and Figure 13 As shown in (a), because the first direction is opposite to the second direction, the tabs of the first cell group 100 and the second cell group 200 are spaced back-to-back, and the tabs of the third cell group 300 and the fourth cell group 400 are also spaced back-to-back. This achieves the shortest tab height while meeting the multi-tab stacked core design assembly requirements, and the tab heights of the first stacked core 3 and the second cell are consistent, avoiding the occurrence of multi-specification tab die-cutting parameters. This invention does not specifically limit the above welding and fixing method; any welding method well known to those skilled in the art can be used, including but not limited to laser welding, ultrasonic welding, etc. Figure 18 As shown, those skilled in the art can, according to actual conditions, set a first pre-soldering area S1 on the electrode tab for height positioning, and the design specifications of the first pre-soldering area S1 are larger than the final solder mark specifications. Specifically, the length d5 ​​of the first pre-soldering area S1 is 16-20mm, the width d6 is 6-10mm, and the distance d7 from the bottom end of the first pre-soldering area S1 to the bottom end of the electrode tab is 8-10mm. The electrode tab is preferably fixed by ultrasonic welding. The welding power of the first positive electrode tab 31, the second positive electrode tab 41, the third positive electrode tab, and the fourth positive electrode tab is 1300-2300W; the welding power of the first negative electrode tab 32, the second negative electrode tab 42, the third negative electrode tab, and the fourth positive and negative electrode tab is 1500-2500W.

[0108] In step (2), the first core assembly includes: using adhesive tape to attach and fix the first battery cell group 100 to the second battery cell group 200, or the third battery cell group 300 to the fourth battery cell group 400.

[0109] In step (3), the first connecting piece 1 and the second connecting piece 9 are in an "intermediate state." The first bent portion 121 and the second bent portion 131 of the first connecting piece 1 are used to connect the positive electrode tabs of the first stacked core 3 and the second stacked core 4 in parallel. The first bent portion 121 and the second bent portion 131 of the second connecting piece 9 are used to connect the negative electrode tabs of the first stacked core 3 and the second stacked core 4 in parallel. The connection between the connecting piece and the stacked core is achieved by welding, so that the first connecting piece 1 and the second connecting piece 9 are arranged side by side. This invention does not specifically limit the above welding method; any welding method well known to those skilled in the art can be used, including but not limited to laser welding, ultrasonic welding, etc. Figure 19 As shown, the present invention can determine the height of a second pre-welding area S2 by setting a second pre-welding area S2 on the second side of the first bend 121 and the second bend 131 according to the actual flow rate and effective filtration area. Specifically, the length d8 of the second pre-welding area S2 is 12-16 mm, the width d9 is 4-8 mm, and the distance d10 from the bottom of the second pre-welding area S2 to the bottom of the bend is 9-11 mm. The welding and fixing are preferably performed using ultrasonic welding, with the welding power of the first connecting piece 1 being 2300-3200 W and the welding power of the second connecting piece 9 being 3500-4500 W.

[0110] In step (4), such as Figure 14 As shown, the first stacked core 3 and the second stacked core 4 are rotated outward by 90°, so that the first stacked core 3 and the second stacked core 4 are on the same plane. At this time, the first positive electrode tab 31 and the first negative electrode tab 32 on the first stacked core 3, which are gathered along the first direction, are folded, and the second positive electrode tab 41 and the second negative electrode tab 42 on the second stacked core 4, which are gathered along the second direction, are approximately unfolded. The third positive electrode tab and the third negative electrode tab on the third stacked core, which are gathered along the first direction, are folded, and the fourth positive electrode tab and the fourth negative electrode tab on the fourth stacked core, which are gathered along the second direction, are approximately unfolded. Subsequently, the cover plate assembly 2 is welded and fixed to the first surface of the connecting body 12, so that the first cell electrode post 22 matches the receiving protrusion on the first connecting piece 1, and the second cell electrode post matches the receiving protrusion on the second connecting piece 9, so that it is well positioned and does not occupy the internal cavity space of the housing 7.

[0111] In step (5), the secondary bending includes: as follows Figure 20As shown, a folding knife 8 is used to press the first bent portion 121 or the second bent portion 131, causing the first bent portion 121 or the second bent portion 131 to gradually bend towards the second surface of the connecting body 12 along the paths a, a', and a'' until it fits against the connecting body 12. Specifically, the thickness of the folding knife 8 is 2-3 mm. After the cover plate assembly 2 is welded and fixed, the operator can insert the folding knife 8 through the clearance opening 21 of the insulating layer 10 to press the first bent portion 121 and the second bent portion 131 to continue bending and fit against the connecting body 12. At this time, the first positive electrode tab 31 and the first negative electrode tab 32, which are gathered along the first direction on the first stack core 3, form a "U" shape; the second positive electrode tab 41 and the second negative electrode tab 42, which are gathered along the second direction on the second stack core 4, form an "S" shape; the third positive electrode tab and the third negative electrode tab, which are gathered along the first direction on the third stack core, form a "U" shape; and the fourth positive electrode tab and the fourth negative electrode tab, which are gathered along the second direction on the fourth stack core, form an "S" shape.

[0112] In step (5), the secondary core assembly includes: using adhesive tape to attach and fix the first stacked core 3 and the second stacked core 4, that is, as the first bending part 121 and the second bending part 131 are flattened, the second battery cell group 200 and the third battery cell group 300 are combined.

[0113] In step (5), before inserting the housing 7, a support bracket 6 and a protective layer 5 are fabricated in the inner cavity of the housing 7 by hot-melt welding. During the insertion of the housing 7, pressure is applied using a pressure mechanism commonly used in the art until the cover assembly 2 matches the housing 7. After the insertion is completed, the outer periphery of the top cover body is welded and fixed to the housing 7.

[0114] The battery of this invention adopts a top-mounted multi-level tab stacked structure with small tab polarization. It is assembled with four cores, which facilitates cell turnover. At the same time, the flexible design of the connecting piece improves the current carrying capacity. According to different manufacturing requirements, the connecting piece can be transformed into different bending states to meet the assembly production requirements. It also makes the height of the tabs required for multi-level tab welding smaller, reducing the cost of the cell, optimizing the battery weight, and making the structure compact, thereby improving the utilization rate of the inner cavity of the casing 7.

[0115] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A high-capacity battery, characterized in that, The high-capacity battery includes a casing, a cover plate assembly, a first connecting piece, a second connecting piece, and a battery module; the battery module includes at least two stacked cores, which are sequentially stacked in the inner cavity of the casing; the top of the casing has an opening, and the cover plate assembly is disposed at the opening; The stacked core is provided with a first adapter component and a second adapter component. The first adapter components of two adjacent stacked cores are connected in parallel through the first connecting piece, and the second adapter components of two adjacent stacked cores are connected in parallel through the second connecting piece. The first connecting piece and the second connecting piece independently include a connecting body, the connecting body having a first surface and a second surface opposite to each other, the first surface being connected to the cover plate assembly, and the second surface being close to the stacked core; both ends of the connecting body are bent toward the second surface to form a first bent portion and a second bent portion, the first bent portion and the second bent portion of the first connecting piece are respectively connected to the first transition assemblies of two adjacent stacked cores, and the first bent portion and the second bent portion of the second connecting piece are respectively connected to the second transition assemblies of two adjacent stacked cores; The first bend and the second bend each have a first side and a second side, which are independently opposite to each other. The first side of the first bend fits into the connecting body, and the second side of the first bend connects to the first adapter component or the second adapter component. The first side of the second bend fits into the connecting body, and the second side of the second bend connects to the first adapter component or the second adapter component; The stacked core includes a first battery cell group and a second battery cell group stacked in sequence. The first battery cell group has a first positive electrode tab and a first negative electrode tab that converge in a first direction at one end near the cover plate assembly. The second battery cell group has a second positive electrode tab and a second negative electrode tab that converge in a second direction at one end near the cover plate assembly. The first direction is opposite to the second direction. The first positive electrode tab is U-shaped, the second positive electrode tab is S-shaped, and they are independently connected to the first connecting piece to form the first adapter assembly; the first negative electrode tab is U-shaped, the second negative electrode tab is S-shaped, and they are independently connected to the second connecting piece to form the second adapter assembly.

2. The high-capacity battery according to claim 1, characterized in that, The cover assembly includes a top cover body, on which a first battery cell terminal and a second battery cell terminal are disposed. The first battery cell terminal is located inside the housing and is connected to the first connecting piece. The second battery cell terminal is located inside the housing and is connected to the second connecting piece. An insulating layer is provided on the surface of the top cover body near the inner cavity of the housing, and the insulating layer extends toward the inner cavity of the housing; A gap is left between the insulating layer and the outer edge of the connecting body.

3. The high-capacity battery according to claim 2, characterized in that, The height of the first and second cell terminals within the housing is greater than the height of the insulating layer. The second surface of the connecting body is provided with a receiving protrusion, which protrudes toward the inner cavity of the housing; The end of the first cell electrode post extending out of the insulating layer is located within the receiving protrusion of the first connecting piece; The end of the second cell terminal extending out of the insulating layer is located within the receiving protrusion of the second connecting piece; In the first or second direction, the linear distance between the insulating layer and the outer edge of the connecting body is 1~2mm; The insulating layer also has clearance openings.

4. The high-capacity battery according to claim 3, characterized in that, The surface of the connecting body is provided with two thinning grooves, and bending along the two thinning grooves respectively forms the first bending part and the second bending part; The width of the thinning groove is 3~4mm, and the depth of the thinning groove is 0.2~0.5mm; The connecting body has two opposing arc-shaped openings on both sides; A foolproof angle is provided along the outer edge of the receiving convex hull.

5. The high-capacity battery according to claim 3, characterized in that, The bottom of the inner cavity of the housing is also provided with a support plate; The inner cavity sidewall of the housing is also provided with a protective layer, which surrounds the outer periphery of the battery module, and the two ends of the protective layer are respectively connected to the insulating layer and the support plate.

6. A method for preparing a high-capacity battery according to any one of claims 1-5, characterized in that, The preparation method includes: The first connecting piece is used to connect the first transition components of two adjacent stacked cores in parallel; The second connecting piece is used to connect the second transition components of two adjacent stacked cores in parallel; The first connecting piece and the second connecting piece are independently connected to the cover plate assembly, and then installed into the housing to obtain a high-capacity battery.

7. The preparation method according to claim 6, characterized in that, The preparation method includes the following steps: (1) Bend the first bending portion and the second bending portion of the first connecting piece and the second connecting piece once, so that the first bending portion and the second bending portion are independently perpendicular to the plane of the connecting body; (2) The first positive electrode and the first negative electrode of the first battery cell group are brought together in the first direction, and the second positive electrode and the second negative electrode of the second battery cell group are brought together in the second direction. Then the first battery cell group and the second battery cell group are combined once to obtain stacked cores. (3) Repeat step (2) to make two stacked cores, which are referred to as the first stacked core and the second stacked core respectively; (4) The first positive electrode tab and the second positive electrode tab of the first stack core are respectively welded and fixed to the second side of the first bend of the first connecting piece, and the first negative electrode tab and the second negative electrode tab are welded and fixed to the second side of the first bend of the second connecting piece; the first positive electrode tab and the second positive electrode tab of the second stack core are welded and fixed to the second side of the second bend of the first connecting piece, and the first negative electrode tab and the second negative electrode tab are welded and fixed to the second side of the second bend of the second connecting piece; (5) Fold the first stack of cores and the second stack of cores in a direction away from each other, and weld and fix the cover plate assembly so that the cover plate assembly is connected to the first connecting piece and the second connecting piece respectively; (6) The first and second bending portions of the first connecting piece and the second connecting piece are bent twice, so that the first side of the first bending portion and the second bending portion fits into the main body, realizing the second core of the first stack and the second stack, and then it is installed into the housing to obtain a high-capacity battery.

8. The preparation method according to claim 7, characterized in that, The secondary bending includes: pressing the first bending part or the second bending part with a folding knife, so that the first bending part or the second bending part bends toward the side closer to the second surface of the connecting body, until it fits against the connecting body; The thickness of the folding knife is 2~3mm.

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