Large-size laminated battery and assembly method thereof

Abstract

The present invention provides a large-size laminated battery and an assembly method. The large-size laminated battery includes a battery cover, a battery lower shell with an open top, and a battery cell, wherein the battery cell is disposed within the battery lower shell. The battery cell includes at least two stacked winding core units, wherein the positive and negative electrode tabs of the winding core units are located on the same side of the winding core units, and the positive electrode tab is welded to a first positive electrode connecting tab, and the negative electrode tab is welded to a first negative electrode connecting tab. The battery cover is provided with a positive electrode column and a negative electrode column, and the inner side of the battery cover is provided with a second positive electrode connecting tab corresponding to and welded to the positive electrode column, and a second negative electrode connecting tab corresponding to and welded to the negative electrode column. After the battery cover, battery cell, and battery lower shell are assembled, the first positive electrode connecting tab contacts and is welded to the second positive electrode connecting tab, and the first negative electrode connecting tab contacts and is welded to the second negative electrode connecting tab. The large-size laminated battery designed by the present invention has the advantages of high yield, saving internal battery space, and ensuring battery capacity.

Description

Technical Field

[0001] The present invention belongs to the field of lithium-ion batteries and relates to laminated battery design technology, and in particular to a large-size laminated battery and an assembly method thereof. Background Art

[0002] Lithium-ion power batteries are a new type of high-energy battery successfully developed in the 20th century. They are widely used in mobile phones, portable computers, camcorders, cameras, electric vehicles, and are also used in artificial satellites, aerospace and energy storage.

[0003] At present, with the increasing demand for lithium-ion batteries, the size of battery cells tends to become larger, which in turn increases the number of electrode layers in stacked battery cells, increasing the difficulty of battery assembly. For example, the ultrasonic welding of the tabs during assembly becomes more difficult, and this process can lead to a decrease in the battery yield rate. For another example, during battery assembly, due to the large thickness of the battery cell, longer positive and negative tabs are required to ensure the coverage area of the ultrasonic welding mark. The larger tabs will occupy a certain amount of space, thereby reducing the available space inside the battery and affecting the battery capacity. Summary of the Invention

[0004] The purpose of the present invention is to improve the assembly efficiency of large-size laminated battery cells, while increasing the available space inside the battery to increase the capacity of the battery, and then improve the existing laminated battery, and design a large-size laminated battery and its assembly method.

[0005] The technical solutions for achieving the purpose of the invention are as follows:

[0006] In a first aspect, the present invention provides a large-size laminated battery, comprising a battery upper cover, a battery lower shell with an upper end opening, and a battery cell, wherein the battery cell is arranged in the battery lower shell.

[0007] The battery cell includes at least two stacked winding core units, the positive electrode tab and the negative electrode tab of the winding core unit are located on the same side of the winding core unit, and the positive electrode tab is welded to the first positive electrode connecting piece, and the negative electrode tab is welded to the first negative electrode connecting piece.

[0008] Among them, the battery cover is provided with a positive electrode column and a negative electrode column, and the inner side of the battery cover is provided with a second positive electrode connecting piece corresponding to and welded with the positive electrode column, and a second negative electrode connecting piece corresponding to and welded with the negative electrode column.

[0009] After the battery cover, battery core and battery lower shell are assembled, the first positive electrode connecting piece contacts and is welded to the second positive electrode connecting piece, and the first negative electrode connecting piece contacts and is welded to the second negative electrode connecting piece.

[0010] The large-size laminated battery designed by the present invention is an improvement on the existing laminated battery. First, a first positive electrode connecting piece is connected to the positive electrode tab of the core unit, and a first negative electrode connecting piece is connected to the negative electrode tab of the core unit, and then at least two core units are stacked to form a battery cell; secondly, a second positive electrode connecting piece is connected to the positive electrode column on the battery cover, and a second negative electrode connecting piece is connected to the negative electrode column on the battery cover; the battery cover and the battery cell are assembled, the first positive electrode connecting piece is in contact with and welded to the second positive electrode connecting piece, and the first negative electrode connecting piece is in contact with and welded to the second negative electrode connecting piece, and then the large-size laminated battery is assembled into the lower shell of the battery.

[0011] The large-size laminated battery designed in the present invention is designed with positive electrode connecting plates (including first positive electrode connecting plates and second positive electrode connecting plates) and negative electrode connecting plates (including first negative electrode connecting plates and second negative electrode connecting plates), which can achieve the purpose of reducing the number of tab layers during ultrasonic welding, while saving space under the battery cover, reducing the size of the electrode sheets, and ensuring the battery capacity.

[0012] In one embodiment of the winding core unit of the present invention, the winding core unit includes two stacked laminated cores, the positive electrode tabs of the two laminated cores are welded to the same first positive electrode connecting sheet, and the negative electrode tabs of the two laminated cores are welded to the same first negative electrode connecting sheet.

[0013] Furthermore, a first rectangular groove is opened in the middle of the first positive electrode connecting piece, the first rectangular groove forms a first fuse protection structure, and the positive electrode tabs of the two laminated cores are respectively located on both sides of the first rectangular groove.

[0014] A second rectangular groove is opened in the middle of the first negative electrode connecting piece, the second rectangular groove forms a second fuse protection structure, and the negative electrode tabs of the two laminated cores are respectively located on both sides of the second rectangular groove.

[0015] In another embodiment of the winding core unit of the present invention, the winding core unit includes two stacked laminated cores, the positive electrode tab of each laminated core corresponds to a first positive electrode connecting piece, and the negative electrode tab of each laminated core corresponds to a first negative electrode connecting piece.

[0016] In one embodiment of the above-mentioned first negative electrode connecting sheet, second negative electrode connecting sheet, first positive electrode connecting sheet, and second positive electrode connecting sheet, the above-mentioned first negative electrode connecting sheet, second negative electrode connecting sheet, first positive electrode connecting sheet, and second positive electrode connecting sheet all include a first welding sheet and a second welding sheet formed by bending the first welding sheet.

[0017] In one embodiment of the battery cell of the present invention, the battery cell has 2 to 8 winding core units.

[0018] In one embodiment of the large-size laminated battery of the present invention, an explosion-proof valve is further provided on the battery upper cover.

[0019] In a second aspect, the present invention further provides a method for assembling a large-size laminated battery, which is used to assemble the large-size laminated battery of the first aspect, comprising:

[0020] Welding the positive electrode tab of the winding core unit to the first positive electrode connecting piece, and welding the negative electrode tab to the first negative electrode connecting piece; stacking and fixing several winding core units to form a battery cell;

[0021] Assemble the positive electrode column and the negative electrode column onto the battery cover, set the second positive electrode connecting piece on the inner side of the battery cover and laser weld it to the positive electrode column, and set the second negative electrode connecting piece on the inner side of the battery cover and laser weld it to the negative electrode column;

[0022] The first positive electrode connecting piece of the battery cover contacts and is welded to the second positive electrode connecting piece of the battery cell. At the same time, the first negative electrode connecting piece of the battery cover contacts and is welded to the second negative electrode connecting piece of the battery cell. The battery cover and the battery cell are assembled into one piece.

[0023] Assemble the battery cover and battery cells into the battery lower shell, and weld the seams to form a large-size laminated battery.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows: the large-size laminated battery designed by the present invention is designed with positive electrode connecting plates (including a first positive electrode connecting plate and a second positive electrode connecting plate) and negative electrode connecting plates (including a first negative electrode connecting plate and a second negative electrode connecting plate), which can achieve the purpose of reducing the number of tab layers during ultrasonic welding; it can save space under the battery cover, reduce the size of the electrode, and ensure the battery capacity; and improve the yield rate of large-size laminated batteries. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] To more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are merely for the purpose of more clearly illustrating the embodiments of the present invention or the technical solutions in the prior art. Those skilled in the art can also derive other drawings based on these drawings without inventive effort.

[0026] Figure 1 This is a schematic diagram of the structure of a large-sized laminated battery in Example 1;

[0027] Figure 2 A schematic diagram of two laminated cores of the core unit in Example 1 after being stacked;

[0028] Figure 3 Schematic diagram of the unfolding of two laminated cores of the core unit in Example 1;

[0029] Figure 4 Another schematic diagram of two laminated cores of the core unit in Example 1 after being stacked;

[0030] Figure 5 Schematic diagram of the inner wall position of the battery cover in Example 1;

[0031] Figure 6 Schematic diagram of the outer wall position of the battery cover in Example 1;

[0032] Figure 7 Schematic diagram of the assembly of the battery cover and the battery cell in Example 2;

[0033] Among them, 1. Battery cover; 2. Battery lower shell; 3. Battery cell; 4. Positive column; 5. Negative column; 6. Second positive electrode connecting piece; 7. Second negative electrode connecting piece; 8. Explosion-proof valve; 31. Winding core unit; 32. Positive electrode tab; 33. Negative electrode tab; 34. First positive electrode connecting piece; 35. First negative electrode connecting piece; 36. Laminated winding core; 37. First rectangular groove; 38. Second rectangular groove. DETAILED DESCRIPTION

[0034] The present invention will be further described below with reference to specific embodiments, and the advantages and features of the present invention will become clearer as the description proceeds. However, these embodiments are merely exemplary and do not constitute any limitation to the scope of the present invention. It should be understood by those skilled in the art that the details and forms of the technical solutions of the present invention may be modified or replaced without departing from the spirit and scope of the present invention, and such modifications and replacements fall within the scope of protection of the present invention.

[0035] In the description of this embodiment, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the invention.

[0036] Furthermore, the terms "first," "second," "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature identified with "first," "second," etc., may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0037] Example 1:

[0038] This embodiment provides a large-size laminated battery. Figure 1 As shown, the large-size laminated battery includes a battery upper cover 1, a battery lower shell 2 with an upper end opening, and a battery cell 3, wherein the battery cell 3 is arranged in the battery lower shell 2.

[0039] The battery cell 3 includes at least two stacked winding core units 31. In this embodiment, the number of winding core units 31 is preferably 2 to 8. Figure 2 and Figure 3 As shown, the positive electrode tab 32 and the negative electrode tab 33 of the winding core unit 31 are located on the same side of the winding core unit 31 , and the positive electrode tab 32 is welded to the first positive electrode connecting tab 34 , and the negative electrode tab 33 is welded to the first negative electrode connecting tab 35 .

[0040] In one embodiment of the core unit 31 of the present invention, the core unit 31 includes a stacked laminate core 36.

[0041] In one embodiment of the core unit 31 of the present invention, the core unit 31 includes two stacked laminate cores 36, such as Figure 3 As shown, Figure 3 This is a schematic diagram of two laminated cores 36 unfolded before stacking. The positive electrode tabs 32 of the two laminated cores 36 are welded to the same first positive electrode connecting piece 34, and the negative electrode tabs 33 of the two laminated cores 36 are welded to the same first negative electrode connecting piece 35.

[0042] Further, such as Figure 3 As shown, a first rectangular groove 37 is defined in the middle of the first positive electrode connecting tab 34. The first rectangular groove 37 forms a first fuse protection structure, and the positive electrode tabs 32 of the two laminated cores 36 are located on either side of the first rectangular groove 37. A second rectangular groove 38 is defined in the middle of the first negative electrode connecting tab 35. The second rectangular groove 38 forms a second fuse protection structure, and the negative electrode tabs 33 of the two laminated cores 36 are located on either side of the second rectangular groove 38.

[0043] In another embodiment of the core unit of the present invention, Figure 4 As shown, the winding core unit 31 includes two stacked laminated cores 36 , the positive electrode tab 32 of each laminated core 36 corresponds to a first positive electrode connecting piece 34 , and the negative electrode tab 33 of each laminated core 36 corresponds to a first negative electrode connecting piece 35 .

[0044] Among them, such as 5 and Figure 6 As shown, the battery cover 1 is provided with a positive electrode column 4 and a negative electrode column 5, and the inner side of the battery cover 1 is provided with a second positive electrode connecting piece 6 corresponding to and welded with the positive electrode column 4, and a second negative electrode connecting piece 7 corresponding to and welded with the negative electrode column 5.

[0045] Furthermore, in order to ensure the safety of large-size laminated batteries during operation, Figure 5 and Figure 6 As shown, the battery cover 1 is further provided with an explosion-proof valve 8.

[0046] After the battery cover 1 , battery cell 3 , and battery lower shell 2 are assembled, the first positive electrode connecting piece 34 contacts and is welded to the second positive electrode connecting piece 6 , and the first negative electrode connecting piece 35 contacts and is welded to the second negative electrode connecting piece 7 .

[0047] In one embodiment of the first negative electrode connecting piece 35, the second negative electrode connecting piece 7, the first positive electrode connecting piece 34, and the second positive electrode connecting piece 6, as shown in FIG. Figures 2 to 5 As shown, the above-mentioned first negative electrode connecting piece 35, second negative electrode connecting piece 7, first positive electrode connecting piece 34, and second positive electrode connecting piece 6 all include a first welding piece and a second welding piece formed by bending the first welding piece, wherein the first welding piece is used for ultrasonic welding of the negative electrode tab 33 or the positive electrode tab 32, and the second welding piece is used for contacting and welding the second welding piece of the second positive electrode connecting piece 6 with the second welding piece of the first positive electrode connecting piece 34 when the battery cover 1 and the battery cell 3 are assembled; and the second welding piece of the second negative electrode connecting piece 7 is contacting and welding the second welding piece of the first negative electrode connecting piece 35.

[0048] The large-size laminated battery provided in this embodiment is formed by connecting the first positive electrode connecting piece 34 to the positive electrode tab 32 of the core unit 31, and connecting the first negative electrode connecting piece 35 to the negative electrode tab 33 of the core unit 31, and then stacking at least two core units 31 to form a battery cell 3; secondly, by connecting the second positive electrode connecting piece 6 to the positive electrode column 4 on the battery cover 1, and connecting the second negative electrode connecting piece 7 to the negative electrode column 5 on the battery cover 1; assembling the battery cover 1 and the battery cell 3, so that the first positive electrode connecting piece 34 is in contact with and welded to the second positive electrode connecting piece 6, and the first negative electrode connecting piece 35 is in contact with and welded to the second negative electrode connecting piece 7, and then assembling them into the battery lower shell 2 to form a large-size laminated battery.

[0049] The large-size laminated battery designed in the present invention is designed with positive electrode connecting plates (including first positive electrode connecting plates and second positive electrode connecting plates) and negative electrode connecting plates (including first negative electrode connecting plates and second negative electrode connecting plates), which can achieve the purpose of reducing the number of tab layers during ultrasonic welding, while saving space under the battery cover, reducing the size of the electrode sheets, and ensuring the battery capacity.

[0050] Example 2:

[0051] This embodiment provides an assembly method for a large-size laminated battery, which is used to assemble the large-size laminated battery of Example 1. This embodiment describes that the core unit 31 of Example 1 contains two laminated cores 36, and the two laminated cores 36 are welded to the first positive electrode connecting piece 34 and the first negative electrode connecting piece 35 at the same time.

[0052] A method for assembling a large-size laminated battery, comprising:

[0053] Step 1: Weld the positive electrode tab 32 of the winding core unit 31 to the first positive electrode connecting piece 34, and weld the negative electrode tab 33 to the first negative electrode connecting piece 35; stack and fix several winding core units 31 to form a battery cell 3.

[0054] Specifically, during operation, the two laminated cores 36 of the core unit 31 are arranged side by side, and the positive pole tabs 32 of the two laminated cores 36 are on the first positive electrode connecting sheet 34 and are respectively located on both sides of the first rectangular groove 37, and the negative pole tabs 33 of the two laminated cores 36 are on the first negative electrode connecting sheet 35 and are respectively located on both sides of the second rectangular groove 38; the positive pole tab 32 is welded to the first positive electrode connecting sheet 34 to form an ultrasonic welding mark, and the negative pole tab 33 is welded to the first negative electrode connecting sheet 35 to form an ultrasonic welding mark; then the two laminated cores 36 are folded in half to form the core unit 31.

[0055] When there are more than two winding core units 31, the two or more winding core units 31 are stacked and fixed together with a bandage or tape to form a battery core 3. Figure 7 shown.

[0056] In this step, if the first negative electrode connecting piece 35, the second negative electrode connecting piece 7, the first positive electrode connecting piece 34, and the second positive electrode connecting piece 6 include a first welding piece and a second welding piece formed by bending the first welding piece, the positive electrode tab 32 and the negative electrode tab 33 are respectively welded to the first welding piece.

[0057] Step 2: Assemble the positive electrode column 4 and the negative electrode column 5 onto the battery cover 1, set the second positive electrode connecting piece 6 to the inner side of the battery cover 1 and laser weld it to the positive electrode column 4, and set the second negative electrode connecting piece 7 to the inner side of the battery cover 1 and laser weld it to the negative electrode column 5.

[0058] Step 3: The second positive electrode connector 6 of the battery cover 1 is brought into contact with and welded to the first positive electrode connector 34 of the battery cell 3. Simultaneously, the second negative electrode connector 7 of the battery cover 1 is brought into contact with and welded to the first negative electrode connector 35 of the battery cell 3, thereby integrally assembling the battery cover 1 and the battery cell 3. Specifically, laser welding can be used as the welding method in this step, and the resulting weld mark is a laser weld mark.

[0059] In this step, if the first negative electrode connecting piece 35, the second negative electrode connecting piece 7, the first positive electrode connecting piece 34, and the second positive electrode connecting piece 6 contain a first welding piece and a second welding piece formed by bending the first welding piece, after the battery cover 1 and the battery cell 3 are assembled, it is also necessary to weld the second welding piece between the first negative electrode connecting piece 35 and the second negative electrode connecting piece 7; and weld the second welding piece between the first positive electrode connecting piece 34 and the second positive electrode connecting piece 6, so that the battery cover 1 and the battery cell 3 are assembled into one.

[0060] Step 4: Assemble the battery cover 1 and the battery core 3 into the battery lower shell 2, and weld the seams to form a large-size laminated battery.

[0061] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

[0062] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A large-size laminated battery, comprising a battery upper cover, a battery lower shell with an upper opening, and a battery cell, wherein the battery cell is disposed in the battery lower shell, characterized in that: The battery cell comprises at least two stacked winding core units, wherein the positive electrode tab and the negative electrode tab of the winding core unit are located on the same side of the winding core unit, and the positive electrode tab is welded to the first positive electrode connecting tab, and the negative electrode tab is welded to the first negative electrode connecting tab; The battery cover is provided with a positive electrode column and a negative electrode column, and the inner side of the battery cover is provided with a second positive electrode connecting piece corresponding to and welded to the positive electrode column, and a second negative electrode connecting piece corresponding to and welded to the negative electrode column; After the battery upper cover, the battery cell, and the battery lower shell are assembled, the first positive electrode connecting piece contacts and is welded to the second positive electrode connecting piece, and the first negative electrode connecting piece contacts and is welded to the second negative electrode connecting piece; The first negative electrode connecting piece, the second negative electrode connecting piece, the first positive electrode connecting piece, and the second positive electrode connecting piece all include a first welding piece and a second welding piece formed by bending the first welding piece; wherein, the second welding pieces located on the same side are welded to each other, and the positive electrode tab and the negative electrode tab of each of the winding core units are correspondingly welded to the first welding piece on the corresponding side, so as to reduce the space occupied by the tab by reducing the length of the tab while increasing the welding strength of the tab, wherein, the positive electrode tab and the negative electrode tab are located on the upper side of the winding core unit, the first welding piece is located on the upper side of the positive electrode tab and the negative electrode tab, and the second welding piece is located on the left and right sides of the winding core unit.

2. The large-size laminated battery according to claim 1, characterized in that: The winding core unit includes two stacked laminated cores, the positive electrode tabs of the two laminated cores are welded to the same first positive electrode connecting sheet, and the negative electrode tabs of the two laminated cores are welded to the same first negative electrode connecting sheet.

3. The large-size laminated battery according to claim 2, characterized in that: A first rectangular groove is formed in the middle of the first positive electrode connecting sheet, the first rectangular groove forms a first fuse protection structure, and the positive electrode tabs of the two laminated cores are respectively located on both sides of the first rectangular groove; A second rectangular groove is opened in the middle of the first negative electrode connecting piece, the second rectangular groove forms a second fuse protection structure, and the negative electrode tabs of the two laminated cores are respectively located on both sides of the second rectangular groove.

4. The large-size laminated battery according to claim 1, characterized in that: The winding core unit includes two stacked laminated cores, the positive electrode tab of each laminated core corresponds to one of the first positive electrode connecting sheets, and the negative electrode tab of each laminated core corresponds to one of the first negative electrode connecting sheets.

5. The large-size laminated battery according to claim 1, characterized in that: The battery cell has 2 to 8 winding core units.

6. The large-size laminated battery according to claim 1, characterized in that: The battery upper cover is also provided with an explosion-proof valve.

7. A method for assembling a large-size laminated battery, for assembling the large-size laminated battery according to any one of claims 1 to 6, characterized in that: include: Welding the positive electrode tab of the winding core unit to the first positive electrode connecting piece, and welding the negative electrode tab to the first negative electrode connecting piece; stacking and fixing several winding core units to form a battery cell; Assemble the positive electrode column and the negative electrode column onto the battery cover, set the second positive electrode connecting piece on the inner side of the battery cover and laser weld it to the positive electrode column, and set the second negative electrode connecting piece on the inner side of the battery cover and laser weld it to the negative electrode column; The first positive electrode connecting piece of the battery cover contacts and is welded to the second positive electrode connecting piece of the battery cell. At the same time, the first negative electrode connecting piece of the battery cover contacts and is welded to the second negative electrode connecting piece of the battery cell. The battery cover and the battery cell are assembled into one piece. Assemble the battery cover and battery cells into the battery lower shell, and weld the seams to form a large-size laminated battery.

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