Battery and preparation method thereof

Abstract

The invention relates to the technical field of batteries, in particular to a battery and a preparation method thereof. The battery comprises a cuboid-shaped battery shell, a plurality of cylindrical roll cores, a positive electrode current collecting assembly, a negative electrode current collecting assembly, a positive electrode assembly and a negative electrode assembly, during application, after the plurality of roll cores are assembled in the battery shell, due to the cylindrical shape of the roll cores, gaps can be formed even if the adjacent roll cores are attached, and after the battery is used for a long time, the size of the battery is reduced, and the service life of the battery is prolonged. The gaps provide redundant space for volume expansion of the roll core, and the expanded roll core is gradually expanded and spread into the gaps, so that expansion of the roll core can be effectively controlled. Compared with a traditional square shell battery adopting the laminated structure battery cell, the square shell battery has the advantages that the volume and the structural strength of the battery shell do not need to be increased, the volume redundancy and the structural strength design of the battery shell can be reduced, the weight of a structural part is reduced, and the energy density of a battery module and a system is improved.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to batteries and methods for preparing the same. Background Art

[0002] With the rapid development of the new energy industry, lithium-ion batteries are increasingly being used in passenger vehicle powertrains and energy storage. Prismatic batteries, the current mainstream product, have captured a significant market share thanks to their high cell capacity and excellent assembly efficiency. These batteries generally utilize a laminated cell design. During long-term charge and discharge cycles, the volume changes of the active material caused by the insertion and extraction of lithium ions can lead to cumulative expansion across the cell thickness.

[0003] In current prismatic battery structures, the maximum expansion margin over the entire cell lifecycle must be considered during the structural design phase. To ensure the mechanical stability of the system, conservative design solutions are often adopted, such as increasing the structural strength and volume of the battery housing. This directly leads to reduced utilization of the effective space within the battery housing, reducing energy density. Energy density loss due to structural redundancy is particularly prominent in commercial vehicle power battery packs and large energy storage container systems. Addressing these negative effects of current prismatic batteries is a technical issue that needs to be addressed in this field. Summary of the Invention

[0004] In view of this, the present application provides a battery and a preparation method thereof, which can solve the negative effects brought about by the need to improve the structural strength of the battery shell and increase the structural volume of the battery shell of the current square shell battery.

[0005] In a first aspect, the present application provides a battery comprising: a rectangular battery case; a plurality of cylindrical winding cores arranged in parallel, assembled in the battery case, with the central axes of the plurality of winding cores parallel to each other; a positive current collecting assembly connected to the positive electrode ear group of each of the winding cores; a negative current collecting assembly connected to the negative electrode ear group of each of the winding cores; a positive electrode assembly connected to the positive electrode current collecting assembly; and a negative electrode assembly connected to the negative electrode current collecting assembly; wherein the positive electrode current collecting assembly and the negative electrode current collecting assembly are respectively connected to the axial ends of the winding core.

[0006] In combination with the first aspect, in a possible implementation, the winding core includes: a positive electrode sheet, on one side of which a positive electrode ear is protruding; and a negative electrode sheet, on one side of which a negative electrode ear is protruding; the positive electrode sheet, the separator and the negative electrode sheet are stacked on each other and wound to form the winding core, the positive electrode ear is wound to form a positive electrode ear roll, and the negative electrode ear is wound to form a negative electrode ear roll, and the positive electrode ear roll and the negative electrode ear roll are respectively located at the axial ends of the winding core.

[0007] In combination with the first aspect, in a possible implementation, the positive electrode tab drum is provided with a first through hole, and the hole axis direction of the first through hole is different from the axial direction of the core; the negative electrode tab drum is provided with a second through hole, and the hole axis direction of the second through hole is different from the axial direction of the core.

[0008] In combination with the first aspect, in a possible implementation, the hole axis direction of the first through hole is the radial direction of the positive electrode tab roll; the hole axis direction of the first through hole is the radial direction of the negative electrode tab roll.

[0009] In combination with the first aspect, in a possible implementation, the first through hole is located at the junction of the positive tab roll and the positive electrode sheet; the second through hole is located at the junction of the negative tab roll and the negative electrode sheet.

[0010] In combination with the first aspect, in a possible implementation, the positive electrode ear roll is flattened to form a positive electrode ear group, and the negative electrode ear roll is flattened to form a negative electrode ear group; the positive electrode current collecting assembly includes a positive electrode ear group connecting portion and a positive electrode column connecting portion, the positive electrode ear group connecting portion is connected to the positive electrode ear group of each of the winding cores, and the positive electrode column connecting portion is connected to the positive electrode assembly; the negative electrode current collecting assembly includes a negative electrode ear group connecting portion and a negative electrode column connecting portion, the negative electrode ear group connecting portion is connected to the negative electrode ear group of each of the winding cores, and the negative electrode column connecting portion is connected to the negative electrode assembly.

[0011] In combination with the first aspect, in a possible implementation, the positive electrode ear group connection portion includes a plurality of interconnected first semi-circular ring connectors, each of which is connected to each of the positive electrode ear groups; the negative electrode ear group connection portion includes a plurality of interconnected second semi-circular ring connectors, each of which is connected to each of the negative electrode ear groups.

[0012] In combination with the first aspect, in a possible implementation, the positive pole connection portion includes at least one first connecting bar, at least one first semi-circular ring connector is connected to a first connecting bar, and the first connecting bar is provided with at least one first bending guide area; the negative pole connection portion includes at least one second connecting bar, at least one second semi-circular ring connector is connected to a second connecting bar, and the second connecting bar is provided with at least one second bending guide area.

[0013] In combination with the first aspect, in a possible implementation, the positive electrode assembly includes a positive electrode cover plate, which is connected to the first connecting bar; the negative electrode assembly includes a negative electrode cover plate, which is connected to the second connecting bar.

[0014] In a second aspect, the present application provides a method for preparing the aforementioned battery, comprising: coating a positive electrode coating on a partial area of ​​a positive electrode current collector to form a positive electrode sheet, and forming a positive electrode ear in an uncoated area; coating a negative electrode coating on a partial area of ​​a negative electrode current collector to form a negative electrode sheet, and forming a negative electrode ear in an uncoated area; overlapping the positive electrode sheet, the separator and the negative electrode sheet, and making the positive electrode ear and the negative electrode ear located on opposite sides respectively; winding the overlapped positive electrode sheet, the separator and the negative electrode sheet to form a cylindrical winding core, wherein the positive electrode ear is wound to form a positive electrode ear roll, and the negative electrode ear is wound to form a negative electrode ear roll; punching a hole in the positive electrode ear roll to form a first through hole, the first through hole The hole axis direction is different from the axial direction of the core, and a second through hole is formed on the negative ear roll, and the hole axis direction of the second through hole is different from the axial direction of the core; a first protective needle is inserted into the first through hole, and a second protective needle is inserted into the second through hole, and the positive ear roll and the negative ear roll are flattened to form a positive ear group and a negative ear group; a positive electrode current collecting assembly is connected to the positive ear group, and a negative electrode current collecting assembly is connected to the negative ear group; multiple cores are installed in a rectangular battery shell; and the positive electrode assembly is connected to the positive electrode current collecting assembly and then assembled on the battery shell, and the negative electrode assembly is connected to the negative electrode current collecting assembly and then assembled on the battery shell.

[0015] When the present application is used, after multiple rolls are assembled in the battery shell, due to the cylindrical shape of the rolls, there will be gaps between adjacent rolls even if they fit together. After long-term use of the battery, these gaps provide redundant space for the volume expansion of the rolls, and the expanded rolls gradually expand and spread into the gaps, thereby effectively controlling the expansion of the rolls. In addition, the cylindrical rolls have excellent production efficiency and structural consistency, which can optimize battery production efficiency. Compared with traditional square shell batteries with laminated structure cells, the present application does not need to increase the volume and structural strength of the battery shell, and the volume redundancy and structural strength design of the battery shell can be reduced, that is, this embodiment equivalently reduces the design volume and design structural strength of the battery shell, thereby equivalently improving the energy density of the battery and equivalently reducing the structural weight of the battery shell. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Shown is a schematic diagram of a battery core structure provided in one embodiment of the present application.

[0017] Figure 2 Shown is a schematic structural diagram of a positive electrode sheet provided in another embodiment of the present application.

[0018] Figure 3 Shown is a schematic structural diagram of a negative electrode sheet provided in another embodiment of the present application.

[0019] Figure 4Shown is a schematic structural diagram of a battery after assembly according to an embodiment of the present application.

[0020] Figure 5 Shown is a schematic structural diagram of a positive electrode current collecting assembly provided in one embodiment of the present application.

[0021] Figure 6 Shown is a schematic structural diagram of a negative electrode current collecting assembly provided in one embodiment of the present application.

[0022] Figure 7 Shown is a schematic structural diagram of multiple battery cells arranged and assembled according to an embodiment of the present application.

[0023] Figure 8 Shown is a schematic structural diagram of a positive electrode assembly provided in one embodiment of the present application.

[0024] Figure 9 Shown is a schematic structural diagram of a negative electrode assembly provided in one embodiment of the present application.

[0025] Figure 10 FIG2 is a schematic diagram showing the steps of a method for preparing a battery provided in one embodiment of the present application. DETAILED DESCRIPTION

[0026] The following will be combined with the accompanying drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of this application.

[0027] Exemplary batteries are as follows: Figure 1 Shown is a schematic diagram of a battery core structure provided in one embodiment of the present application. Figure 2 Shown is a schematic structural diagram of a positive electrode sheet provided in another embodiment of the present application. Figure 3 Shown is a schematic structural diagram of a negative electrode sheet provided in another embodiment of the present application. Figure 4 Shown is a schematic structural diagram of a battery after assembly according to an embodiment of the present application. Figure 5 Shown is a schematic structural diagram of a positive electrode current collecting assembly provided in one embodiment of the present application. Figure 6 Shown is a schematic structural diagram of a negative electrode current collecting assembly provided in one embodiment of the present application. Figure 7 Shown is a schematic structural diagram of multiple battery cells arranged and assembled according to an embodiment of the present application. Figure 8 Shown is a schematic structural diagram of a positive electrode assembly provided in one embodiment of the present application. Figure 9 Shown is a schematic structural diagram of a negative electrode assembly provided in one embodiment of the present application.

[0028] In one embodiment, if Figures 1 to 9 As shown, the battery comprises: a battery case 1, a winding core 2, a positive electrode current collector assembly 3, a negative electrode current collector assembly 4, a positive electrode assembly 5, and a negative electrode assembly 6. The battery case 1 is a rectangular parallelepiped. The winding core 2 is cylindrical and there are multiple winding cores 2. The winding cores 2 are arranged side by side with their central axes parallel to each other. The multiple winding cores 2 are assembled in the battery case 1. The positive electrode current collector assembly 3 is connected to the positive electrode tab group 2032 of each winding core 2, and the negative electrode current collector assembly 4 is connected to the negative electrode tab group 2042 of each winding core 2. The positive electrode assembly 5 is connected to the positive electrode current collector assembly 3, and the negative electrode assembly 6 is connected to the negative electrode current collector assembly 4. The positive electrode current collector assembly 3 and the negative electrode current collector assembly 4 are respectively connected to the axial ends of the winding core 2.

[0029] In this embodiment, when multiple cores 2 are assembled in the battery casing 1, the cylindrical shape of the cores 2 creates gaps between adjacent cores 2, even when they fit snugly. After prolonged battery use, these gaps provide redundant space for the cores 2 to expand, allowing the expanding cores 2 to gradually expand and spread into the gaps, effectively controlling their expansion. The positive and negative current collector assemblies 3 and 4, located at either end of the core 2, limit the axial expansion of the core 2 to a certain extent, thereby reducing the risk of further axial expansion. Furthermore, the positive and negative current collector assemblies 3 and 4 exhibit a certain degree of tensile strength along their surface extension (perpendicular to the axial direction of the core 2), thereby helping to secure the core 2 and limit its axial expansion and displacement. Furthermore, the cylindrical core 2 offers excellent production efficiency and structural consistency, optimizing battery production efficiency. Compared with the traditional square shell battery with laminated structure cells, this embodiment does not need to increase the volume and structural strength of the battery shell 1. The volume redundancy and structural strength design of the battery shell 1 can be reduced. That is, this embodiment is equivalent to reducing the design volume and design structural strength of the battery shell 1, thereby equivalently improving the energy density of the battery and equivalently reducing the structural weight of the battery shell 1.

[0030] In one embodiment, referring to Figures 1-3 As shown, the winding core 2 includes a positive electrode sheet 201 and a negative electrode sheet 202. A positive electrode tab 203 protrudes from one longitudinal side of the positive electrode sheet 201, and a negative electrode tab 204 protrudes from one longitudinal side of the negative electrode sheet 202. The positive electrode sheet 201, separator, and negative electrode sheet 202 are stacked and wound to form the winding core 2. The positive electrode tab 203 is wound to form a positive electrode tab roll 2031, and the negative electrode tab 204 is wound to form a negative electrode tab roll 2041. The positive electrode tab roll 2031 and the negative electrode tab roll 2041 are located at the axial ends of the winding core 2, respectively.

[0031] When this embodiment is used, the length of the positive electrode ear 203 is the same as the length of the positive electrode sheet 201, and the length of the negative electrode ear 204 is the same as the length of the negative electrode sheet 202, thereby forming a full-electrode ear structure. Compared with the traditional partial electrode ear structure, the battery internal resistance of the full-electrode ear structure of this embodiment is lower, so that the core 2 has a high-rate current flow capacity.

[0032] In one embodiment, if Figure 1 As shown, the positive tab drum 2031 has a first through hole 205, the axis of which is different from the axial direction of the winding core 2. The negative tab drum 2041 has a second through hole 206, the axis of which is different from the axial direction of the winding core 2.

[0033] When this embodiment is used, the first through hole 205 and the second through hole 206 allow each circle of the positive electrode ear 203 and each circle of the negative electrode ear 204 to be perforated. After the positive electrode ear roll 2031 and the negative electrode ear roll 2041 are flattened, the perforations of each circle of the positive electrode ear 203 and each circle of the negative electrode ear 204 serve as infiltration channels for the electrolyte to penetrate into the inner part of the core 2, so that the electrolyte can infiltrate the wound battery core more quickly, thereby effectively shortening the infiltration time of the electrolyte, taking into account both production efficiency and battery performance. In addition, the number of the first through hole 205 and the second through hole 206 can be multiple, and the more the number, the higher the infiltration efficiency. Specifically, the first through hole 205 is circular, with a diameter of any value between 0.2 mm and 1.5 mm; the second through hole 206 is circular, with a diameter of any value between 0.2 mm and 1.5 mm.

[0034] In one embodiment, the hole axis direction of the first through hole 205 is the radial direction of the positive electrode tab reel 2031, and the hole axis direction of the first through hole 205 is the radial direction of the negative electrode tab reel 2041, so that the perforation of the positive electrode tab 203 and the perforation of the negative electrode tab 204 are both axially symmetrical, further optimizing the electrolyte infiltration efficiency.

[0035] Specifically, the first through-hole 205 is located at the junction of the positive tab reel 2031 and the positive electrode sheet 201, and the second through-hole 206 is located at the junction of the negative tab reel 2041 and the negative electrode sheet 202. That is, the first through-hole 205 is located at the root of the positive tab reel 2031, and the second through-hole 206 is located at the root of the negative tab reel 2041. This increases the flattening area of ​​the positive tab reel 2031 and the negative tab reel 2041 without flattening the positive tab portion where the first through-hole 205 is located, and without flattening the negative tab portion where the second through-hole 206 is located, thereby effectively reducing the volume of the winding core after the tabs are flattened.

[0036] Before flattening the positive electrode ear reel 2031 and the negative electrode ear reel 2041, protective needles can be inserted into the first through hole 205 and the second through hole 206 respectively to avoid twisting and deformation of the first through hole 205 and the second through hole 206 during the flattening process, that is, to avoid twisting, deformation and misalignment of the perforations of each electrode ear, which may affect the penetration of the electrolyte into the core 2.

[0037] In one embodiment, if Figure 7 As shown, the positive tab roll 2031 is flattened to form a positive tab group 2032, and the negative tab roll 2041 is flattened to form a negative tab group 2042. Figure 5 、 6 As shown in Figures 7 and 8, the positive current collecting assembly 3 includes a positive tab group connection portion 310 and a positive electrode post connection portion 311. The positive tab group connection portion 310 is connected to the positive tab group 2032 of each winding core 2, and the positive electrode post connection portion 311 is connected to the positive electrode assembly 5. The negative current collecting assembly 4 includes a negative tab group connection portion 410 and a negative electrode post connection portion 411. The negative tab group connection portion 410 is connected to the negative tab group 2042 of each winding core 2, and the negative electrode post connection portion 411 is connected to the negative electrode assembly 6. In this embodiment, the positive tab group connection portion 310 electrically connects the positive tab groups 2032, and then conducts electricity to the positive electrode assembly 5 through the positive electrode post connection portion 311; the negative tab group connection portion 410 electrically connects the negative tab groups 2042, and then conducts electricity to the negative electrode assembly 6 through the negative electrode post connection portion 411.

[0038] In one embodiment, if Figure 5 、 6 As shown in Figures 7 and 8, the positive electrode tab group connection portion 310 includes a plurality of interconnected first semi-circular connectors 3101, each of which is connected to a respective positive electrode tab group 2032. The negative electrode tab group connection portion 410 includes a plurality of interconnected second semi-circular connectors 4101, each of which is connected to a respective negative electrode tab group 2042. When this embodiment is used, compared to the strip-shaped connector, the first semi-circular connectors 3101 can increase the docking area between the positive electrode tab group connection portion 310 and the positive electrode tab group 2032, and the second semi-circular connectors 4101 can increase the docking area between the negative electrode tab group connection portion 410 and the negative electrode tab group 2042. Moreover, the semicircular structure of the first semicircular connector 3101 and the second semicircular connector 4101 can take into account both the flow capacity and the lightweight structure. Under the same flow capacity, the thickness of the positive electrode ear group connection part 310 and the negative electrode ear group connection part 410 can be appropriately thinned, thereby improving the space utilization inside the battery.

[0039] Specifically, such as Figure 3 and 4As shown, the positive electrode post connection portion 311 includes at least one first connecting bar 3111, one of which is connected to at least one first semicircular connecting member 3101. The first connecting bar 3111 is provided with at least one first bending guide area 3112, which can be in the form of a notch. The negative electrode post connection portion 411 includes at least one second connecting bar 4111, one of which is connected to at least one second semicircular connecting member 4101. The second connecting bar 4111 is provided with at least one second bending guide area 4112, which can be in the form of a notch. The first bending guide area 3112 improves the degree of freedom of connection between the first connecting bar 3111 and the positive electrode assembly 5, and the second bending guide area 4112 improves the degree of freedom of connection between the second connecting bar 4111 and the negative electrode assembly 6.

[0040] In one embodiment, referring to Figure 8 and Figure 9 The positive electrode assembly 5 includes a positive electrode cover plate 501, which is connected to the first connecting bar 3111. The negative electrode assembly 6 includes a negative electrode cover plate 601, which is connected to the second connecting bar 4111. Figure 5 、 6 7. After welding the positive tab group connection portion 310 to the positive tab group 2032 and the negative tab group connection portion 410 to the negative tab group 2042, the first connecting bar 3111 is folded upward once through a first bending guide 3112 and then connected to the positive electrode cover plate 501. Similarly, the second connecting bar 4111 can be folded upward once through a second bending guide 4112 and then connected to the negative electrode cover plate 601.

[0041] In some embodiments, when there are two first bending guide areas 3112 and two second bending guide areas 4112, the first connecting bar 3111 can be folded in half twice using the two first bending guide areas 3112 before being connected to the positive electrode cover plate 501. Alternatively, the second connecting bar 4111 can be folded in half twice using the two second bending guide areas 4112 before being connected to the negative electrode cover plate 601. Compared to folding in half once, folding in half twice allows for greater flexibility in setting the connection points between the first connecting bar 3111 and the positive electrode cover plate 501, and between the second connecting bar 4111 and the negative electrode cover plate 601. Furthermore, folding in half twice can increase the gap between the first connecting bar 3111 and the positive electrode cover plate 501, and increase the gap between the second connecting bar 4111 and the negative electrode cover plate 601. The first connecting bar 3111 and the second connecting bar 4111 folded in half twice can provide a certain buffering effect, thereby optimizing the shock resistance of the battery structure.

[0042] In some embodiments, when there are three first bending guide areas 3112 and three second bending guide areas 4112, the first connecting bar 3111 can be folded in half three times using the three first bending guide areas 3112 before being connected to the positive electrode cover plate 501. Alternatively, the second connecting bar 4111 can be folded in half three times using the three second bending guide areas 4112 before being connected to the negative electrode cover plate 601. Compared to folding in half twice, folding in half three times allows for greater flexibility in setting the connection points between the first connecting bar 3111 and the positive electrode cover plate 501, and between the second connecting bar 4111 and the negative electrode cover plate 601. Furthermore, the gaps between the first connecting bar 3111 and the positive electrode cover plate 501, and between the second connecting bar 4111 and the negative electrode cover plate 601 can be larger. The first connecting bar 3111 and the second connecting bar 4111 folded in half three times can provide a certain buffering effect, thereby optimizing the shock resistance of the battery structure.

[0043] Based on the above-mentioned embodiments of the number of the first bending guide area 3112 and the second bending guide area 4112, the greater the number of the first bending guide area 3112 and the second bending guide area 4112, the more times the first connecting bar 3111 and the second connecting bar 4111 can be folded in half, thereby making the setting freedom of the connection point between the first connecting bar 3111 and the positive electrode cover plate 501 higher, and making the setting freedom of the connection point between the second connecting bar 4111 and the negative electrode cover plate 601 higher, and can increase the gap between the first connecting bar 3111 and the positive electrode cover plate 501, and the gap between the second connecting bar 4111 and the negative electrode cover plate 601. The first connecting bar 3111 and the second connecting bar 4111 that are folded in half multiple times can play a certain buffering role, and can optimize the seismic resistance of the battery structure.

[0044] Specifically, the positive electrode cover plate 501 is an integrated stamping structure, and the negative electrode cover plate 601 includes a cover plate body, a negative electrode column 602, a safety valve 603 and a liquid injection hole 604. The liquid injection hole is a circular through hole and can be equipped with a seal.

[0045] In addition, in some embodiments, a portion of the battery housing 1 serves as the positive electrode assembly 5, and the first connecting bar 3111 is electrically connected to the battery housing 1, so that the entire battery housing 1 is positively charged. The second connecting bar 4111 is electrically connected to the negative electrode post of the negative electrode cover 601, and the negative electrode post 602 of the negative electrode cover 601 is negatively charged.

[0046] An exemplary preparation method for the aforementioned battery is as follows: Figure 10 The figure shows a schematic diagram of the steps of a method for preparing a battery provided in one embodiment of the present application. The present application also provides a method for preparing the aforementioned battery, such as Figure 10 As shown, the preparation method includes steps 110 to 190, and steps 110 to 190 are described below.

[0047] Step 110 : Coating a positive electrode coating on a portion of the positive electrode current collector to form a positive electrode sheet 201 , and forming a positive electrode tab 203 in the uncoated region.

[0048] In this step, the positive electrode coating is an active material, which can be a sodium ion positive electrode material or a lithium ion positive electrode material.

[0049] Step 120 : Coating a negative electrode coating on a portion of the negative electrode current collector to form a negative electrode sheet 202 , and forming a negative electrode tab 204 in the uncoated area.

[0050] In this step, the negative electrode coating is an active material, which can be a mixture of one or more of graphite, silicon carbon, silicon monoxide, hard carbon, and soft carbon.

[0051] Step 130 : Overlap the positive electrode sheet 201 , the separator, and the negative electrode sheet 202 , with the positive electrode tab 203 and the negative electrode tab 204 being located on opposite sides.

[0052] Step 140 : Wind the overlapped positive electrode sheet 201 , separator, and negative electrode sheet 202 into a cylindrical winding core 2 , wherein the positive electrode tab 203 is wound into a positive electrode tab roll 2031 , and the negative electrode tab 204 is wound into a negative electrode tab roll 2041 .

[0053] Step 150: Punch a hole 205 on the positive electrode tab drum 2031 to form a first through hole. The hole axis direction of the first through hole 205 is different from the axial direction of the winding core 2. Punch a hole 206 on the negative electrode tab drum 2041 to form a second through hole. The hole axis direction of the second through hole 206 is different from the axial direction of the winding core 2.

[0054] Step 160 : insert a first protective needle into the first through hole 205 , insert a second protective needle into the second through hole 206 , and flatten the positive tab reel 2031 and the negative tab reel 2041 to form a positive tab group 2032 and a negative tab group 2042 .

[0055] In this step, the first protective needle and the second protective needle inserted into the first through hole 205 and the second through hole 206 can prevent the first through hole 205 and the second through hole 206 from twisting and deforming during the flattening process, that is, to prevent the twisting, deformation and misalignment of the perforations of each tab from affecting the electrolyte from penetrating into the core 2. After the positive tab reel 2031 and the negative tab reel 2041 are flattened, the first through hole 205 and the second through hole 206 serve as the infiltration channel for the electrolyte to penetrate into the core 2, so that the electrolyte can infiltrate the wound battery core faster, thereby effectively shortening the electrolyte infiltration time, taking into account both production efficiency and battery performance. After flattening the positive tab reel 2031 and the negative tab reel 2041, the first protective needle and the second protective needle can be pulled out.

[0056] Furthermore, the number of the first through hole 205 and the second through hole 206 can be multiple, and a greater number of the first through hole 205 and the second through hole 206 can improve the infiltration efficiency. Specifically, the first through hole 205 is circular, with a diameter ranging from 0.2 mm to 1.5 mm; the second through hole 206 is circular, with a diameter ranging from 0.2 mm to 1.5 mm.

[0057] In one embodiment, the hole axis direction of the first through hole 205 is the radial direction of the positive electrode tab reel 2031, and the hole axis direction of the first through hole 205 is the radial direction of the negative electrode tab reel 2041, so that the perforation of the positive electrode tab 203 and the perforation of the negative electrode tab 204 are both axially symmetrical, further optimizing the electrolyte infiltration efficiency.

[0058] Specifically, the first through-hole 205 is located at the junction of the positive tab reel 2031 and the positive electrode sheet 201, and the second through-hole 206 is located at the junction of the negative tab reel 2041 and the negative electrode sheet 202. That is, the first through-hole 205 is located at the root of the positive tab reel 2031, and the second through-hole 206 is located at the root of the negative tab reel 2041. This increases the flattening area of ​​the positive tab reel 2031 and the negative tab reel 2041 without flattening the positive tab portion where the first through-hole 205 is located, and without flattening the negative tab portion where the second through-hole 206 is located, thereby effectively reducing the volume of the winding core after the tabs are flattened.

[0059] Step 170 : Connect the positive electrode current collecting assembly 3 to the positive electrode tab group 2032 , and connect the negative electrode current collecting assembly 4 to the negative electrode tab group 2042 .

[0060] Step 180 : Load multiple winding cores 2 into a rectangular battery casing 1 .

[0061] Step 190 : Connect the positive electrode assembly 5 to the positive electrode current collecting assembly 3 and then assemble them on the battery housing 1 ; connect the negative electrode assembly 6 to the negative electrode current collecting assembly 4 and then assemble them on the battery housing 1 .

[0062] When this embodiment is in use, after multiple cores 2 are assembled in the battery casing 1, due to the cylindrical shape of the cores 2, there will be gaps between adjacent cores 2 even if they fit together. After long-term use of the battery, these gaps provide redundant space for the volume expansion of the cores 2, and the expanded cores 2 gradually expand and spread into the gaps, thereby effectively controlling the expansion of the cores 2. In addition, the cylindrical cores 2 have excellent production efficiency and structural consistency, which can optimize battery production efficiency. Compared with traditional square shell batteries with laminated structure cells, this embodiment does not need to increase the volume and structural strength of the battery casing 1. The volume redundancy and structural strength design of the battery casing 1 can be reduced, that is, this embodiment equivalently reduces the design volume and design structural strength of the battery casing 1, thereby equivalently improving the energy density of the battery and equivalently reducing the structural weight of the battery casing 1.

[0063] The basic principles of the present application have been described above in conjunction with specific embodiments. However, it should be noted that the advantages, strengths, and effects mentioned in this application are merely illustrative and not restrictive, and it should not be assumed that these advantages, strengths, and effects are required of each embodiment of this application. In addition, the specific details disclosed above are merely illustrative and facilitating understanding, and are not restrictive. The above details do not limit this application to necessarily being implemented using the above specific details.

[0064] The block diagrams of the devices, devices, equipment, and systems involved in this application are merely illustrative examples and are not intended to require or imply that they must be connected, arranged, or configured in the manner shown in the block diagrams. As will be appreciated by those skilled in the art, these devices, devices, equipment, and systems can be connected, arranged, or configured in any manner. Words such as "include," "comprise," "have," and the like are open-ended words, meaning "including but not limited to," and can be used interchangeably therewith. The words "or" and "and" used herein refer to the words "and / or" and can be used interchangeably therewith, unless the context clearly indicates otherwise. The word "such as" used herein refers to the phrase "such as but not limited to," and can be used interchangeably therewith.

[0065] It should also be noted that in the apparatus, device, and method of the present application, each component or each step can be decomposed and / or recombined, and such decomposition and / or recombination should be regarded as equivalent solutions of the present application.

[0066] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use the present application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects without departing from the scope of the present application. Therefore, the present application is not intended to be limited to the aspects shown herein, but rather to be applied in the widest sense consistent with the principles and novel features of the present invention.

[0067] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements, etc. made within the spirit and principles of the present application shall be included in the scope of protection of the present application.

Claims

1. A battery, characterized in that: include: A rectangular battery housing (1); A plurality of cylindrical winding cores (2) arranged in parallel are assembled in the battery housing (1), wherein the central axes of the plurality of winding cores (2) are parallel to each other; A positive electrode current collecting assembly (3) connected to the positive electrode tab group (2032) of each of the winding cores (2); A negative electrode current collecting assembly (4) connected to the negative electrode tab group (2042) of each of the winding cores (2); A positive electrode assembly (5) connected to the positive electrode current collecting assembly (3); and A negative electrode assembly (6) connected to the negative electrode current collecting assembly (4); The positive electrode current collecting assembly (3) and the negative electrode current collecting assembly (4) are respectively connected to the two axial ends of the winding core (2).

2. The battery according to claim 1, characterized in that The winding core (2) comprises: A positive electrode sheet (201) having a positive electrode ear (203) protruding from one side in the longitudinal direction; and A negative electrode sheet (202) has a negative electrode ear (204) protruding from one side in the longitudinal direction; The positive electrode sheet (201), the separator and the negative electrode sheet (202) are stacked on each other and then wound to form the winding core (2); the positive electrode tab (203) is wound to form a positive electrode tab roll (2031); the negative electrode tab (204) is wound to form a negative electrode tab roll (2041); the positive electrode tab roll (2031) and the negative electrode tab roll (2041) are respectively located at two axial ends of the winding core (2).

3. The battery according to claim 2, characterized in that The positive electrode tab reel (2031) is provided with a first through hole (205), and the hole axis direction of the first through hole (205) is different from the axial direction of the reel core (2); The negative electrode ear drum (2041) is provided with a second through hole (206), and the hole axis direction of the second through hole (206) is different from the axial direction of the winding core (2).

4. The battery according to claim 3, characterized in that The hole axis direction of the first through hole (205) is the radial direction of the positive electrode tab reel (2031); The hole axis direction of the first through hole (205) is the radial direction of the negative electrode ear drum (2041).

5. The battery according to claim 4, characterized in that The first through hole (205) is located at the junction of the positive electrode tab drum (2031) and the positive electrode sheet (201); The second through hole (206) is located at the junction of the negative electrode tab roll (2041) and the negative electrode sheet (202).

6. The battery according to claim 3, characterized in that The positive electrode tab reel (2031) is flattened to form a positive electrode tab group (2032), and the negative electrode tab reel (2041) is flattened to form a negative electrode tab group (2042); The positive electrode current collecting assembly (3) comprises a positive electrode tab group connection portion (310) and a positive electrode column connection portion (311), wherein the positive electrode tab group connection portion (310) is connected to the positive electrode tab group (2032) of each of the winding cores (2), and the positive electrode column connection portion (311) is connected to the positive electrode assembly (5); The negative electrode current collecting assembly (4) comprises a negative electrode tab group connection portion (410) and a negative electrode column connection portion (411), wherein the negative electrode tab group connection portion (410) is connected to the negative electrode tab group (2042) of each winding core (2), and the negative electrode column connection portion (411) is connected to the negative electrode assembly (6).

7. The battery according to claim 6, characterized in that The positive electrode tab group connection portion (310) comprises a plurality of first semi-circular ring connectors (3101) connected to each other, each of the first semi-circular ring connectors (3101) being connected to each of the positive electrode tab groups (2032); The negative electrode tab group connecting portion (410) comprises a plurality of second semi-circular ring connecting members (4101) connected to each other, and each of the second semi-circular ring connecting members (4101) is connected to each of the negative electrode tab groups (2042).

8. The battery according to claim 7, characterized in that The positive electrode column connecting portion (311) comprises at least one first connecting bar (3111), at least one first semi-circular ring connecting member (3101) is connected to one first connecting bar (3111), and the first connecting bar (3111) is provided with at least one first bending guide area (3112); The negative electrode column connecting portion (411) comprises at least one second connecting bar (4111), at least one second semi-circular ring connecting piece (4101) is connected to a second connecting bar (4111), and the second connecting bar (4111) is provided with at least one second bending guide area (4112).

9. The battery according to claim 8, characterized in that The positive electrode assembly (5) comprises a positive electrode cover plate (501), and the positive electrode cover plate (501) is connected to the first connecting bar (3111); The negative electrode assembly (6) comprises a negative electrode cover plate (601), and the negative electrode cover plate (601) is connected to the second connecting bar (4111).

10. A method for preparing the battery according to any one of claims 3 to 9, characterized in that: include: A positive electrode coating is applied to a portion of the positive electrode current collector to form a positive electrode sheet (201), and an uncoated region forms a positive electrode tab (203); A negative electrode coating is applied to a portion of the negative electrode current collector to form a negative electrode sheet (202), and an uncoated region forms a negative electrode ear (204); Overlapping the positive electrode sheet (201), the separator, and the negative electrode sheet (202), and positioning the positive electrode tab (203) and the negative electrode tab (204) on opposite sides; The stacked positive electrode sheet (201), separator, and negative electrode sheet (202) are wound to form a cylindrical winding core (2), wherein the positive electrode tab (203) is wound to form a positive electrode tab winding drum (2031), and the negative electrode tab (204) is wound to form a negative electrode tab winding drum (2041); A first through hole (205) is punched on the positive electrode ear drum (2031), wherein the hole axis direction of the first through hole (205) is different from the axial direction of the winding core (2); a second through hole (206) is punched on the negative electrode ear drum (2041), wherein the hole axis direction of the second through hole (206) is different from the axial direction of the winding core (2); A first protective needle is inserted into the first through hole (205), a second protective needle is inserted into the second through hole (206), and the positive electrode tab reel (2031) and the negative electrode tab reel (2041) are flattened to form a positive electrode tab group (2032) and a negative electrode tab group (2042); Connecting a positive electrode current collecting assembly (3) to the positive electrode tab group (2032), and connecting a negative electrode current collecting assembly (4) to the negative electrode tab group (2042); Inserting a plurality of the winding cores (2) into a rectangular parallelepiped battery housing (1); and The positive electrode assembly (5) is connected to the positive electrode current collecting assembly (3) and then assembled on the battery housing (1); the negative electrode assembly (6) is connected to the negative electrode current collecting assembly (4) and then assembled on the battery housing (1).

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