Rectangular cell

Abstract

This invention provides a prismatic cell that overcomes the drawback of the prior art, in which abnormal lithium deposition is likely to occur in the wound material, affecting the performance of the cell. [Solution] The rectangular cell of the present invention includes a housing and two winding body groups 20 housed within the housing. Each winding body group includes at least two winding bodies stacked along a first direction, and the outer circumferential surface of each winding body along the winding direction includes two planar portions and a first corner portion and a second corner portion connected to the opposing ends of the two planar portions, respectively. In the winding body group, the winding body adjacent to the housing along the first direction is the first winding body 31, and the winding body adjacent to another winding body group is the second winding body 32. Each winding body group further includes a first insulating tape 40, the first insulating tape covers at least a portion of the first corner portion 305a of the second winding body, and one end of the first insulating tape extends from the first corner portion of the second winding body to the first corner portion of the first winding body.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium batteries, and particularly to square cells.

Background Art

[0002] The wound body in a square cell is formed by laminating positive and negative electrode sheets and a separator and winding them. The outer peripheral surface along the winding direction of the wound body includes a corner portion and a flat portion. Here, in the corner portion, the outer peripheral surface of the wound body is arc-shaped, and since heat crimping treatment cannot be performed, the contact between the positive and negative electrode sheets and the separator in the corner portion is loose and the gap is large. As a result, lithium is likely to precipitate on the surface of the negative electrode sheet located in the corner portion during the long-term cycling of the cell, affecting the performance of the cell. Furthermore, currently, in general products in mass production, due to restrictions in the manufacturing process, etc., in a square cell having a certain thickness, a multi-stage wound body lamination design is often adopted, the number of corner portions in the cell increases, and the bending angle of the positive and negative electrode sheets and the separator in the corner portion becomes large, so abnormal lithium precipitation further seriously affects the performance of the battery cell.

Summary of the Invention

Problems to be Solved by the Invention

[0003] The technical problem to be solved by the present invention is to provide a square cell for overcoming the defect of the prior art that abnormal lithium precipitation easily occurs in the wound body and it affects the performance of the cell.

Means for Solving the Problems

[0004] The present invention solves the above technical problem by the following technical solutions. A rectangular cell includes a housing and two groups of windings housed within the housing. Each group of windings includes at least two windings stacked along a first direction, and each outer surface of each winding along the winding direction includes two planar portions and a first corner portion and a second corner portion connected to the opposing ends of the two planar portions, respectively, and both of the planar portions are perpendicular to the first direction, and in the group of windings, the winding adjacent to the housing along the first direction is the first winding, and the two planar portions of the first winding include the first planar portion adjacent to the housing, and in the group of windings, the winding adjacent to another group of windings is the second winding. Each of the winding groups further includes a first insulating tape, the first insulating tape covering at least a portion of the first corner of the second winding, and one end of the first insulating tape extending from the first corner of the second winding to the first corner of the first winding.

[0005] The aforementioned rectangular cell is formed by creating a winding group from two or more winding groups, and then housing two of these winding groups within a housing, thereby facilitating the overall processing and manufacturing of the rectangular cell. In this case, by arranging the first insulating tape to cover the first corner portion of each winding within the winding group, the first insulating tape creates a tightening effect on the corner portion of each winding, causing the sheet and separator at the first corner portion of the winding to adhere tightly, thereby improving the lithium deposition phenomenon.

[0006] Furthermore, by extending one end of the first insulating tape not to the first flat portion of the first winding, but through the first corner portion of the second winding to the surface of the first corner portion of the first winding, the covering area of ​​the first insulating tape on the surface of the corner portion of the winding group is increased, and at the same time, the overall thickness of the winding is avoided by placing the first insulating tape on the flat portion of the winding, so that the rectangular cell can accommodate more windings along the first direction and further improve the energy density.

[0007] Preferably, one end of the first insulating tape extends through the first corner portion of the second winding body to the boundary between the first corner portion and the first flat portion of the first winding body.

[0008] If the first insulating tape does not extend to the first flat portion of the first winding body, the covering area of ​​the first insulating tape at the corner portion of the first winding body can be increased by extending the end of the first insulating tape to the boundary between the first corner portion and the first flat portion of the first winding body. Preferably, the other end of the first insulating tape is positioned at the boundary between the first corner portion of the second winding body and the flat portion of the second winding body.

[0009] By positioning the other end of the first insulating tape at the boundary between the first corner portion and the flat portion of the second winding body, the covering area of ​​the first insulating tape at the corner portion of the second winding body can be increased.

[0010] Here, the end of the first insulating tape is positioned at the boundary between the first corner and the flat surface of the second winding, without extending to the flat surface. This avoids increasing the overall thickness of the winding by preventing the first insulating tape from being positioned on the flat surface of the winding, allowing the rectangular cell to accommodate more windings along the first direction and further improve energy density.

[0011] Preferably, the rectangular cell further includes a heat dissipation medium, which is positioned between the two winding groups.

[0012] By placing a heat dissipation medium with thermal conductivity between two adjacent winding groups, the thermal conductivity between the winding groups can be improved, and the overall heat dissipation effect of the rectangular cell can be enhanced.

[0013] Preferably, the two planar portions of the second winding body include a second planar portion adjacent to another group of winding bodies, the heat dissipation medium is positioned between the second planar portions of the two groups of winding bodies, and the heat dissipation medium is connected to the end of the first insulating tape.

[0014] By placing a heat dissipation medium with thermal conductivity between the second planar portions of the two winding body groups, the thermal conductivity between the winding body groups is improved. By connecting the heat dissipation medium to the end of the first insulating tape, the connection relationship between the first insulating tape and each winding body is improved, and the clamping force to each corner of the winding body can be improved.

[0015] At the same time, by connecting the heat dissipation medium to the end of the first insulating tape, the heat conduction path between the heat dissipation medium and the first insulating tape becomes continuous, and the heat from the heat dissipation medium is transferred to the outside through the first insulating tape, improving heat dissipation.

[0016] Preferably, the winding body is formed by winding a positive electrode sheet, a negative electrode sheet, and a separator, the separator is sandwiched between the positive electrode sheet and the negative electrode sheet, and the end of the separator is outside the end of the positive electrode sheet and the negative electrode sheet. The rectangular cell further includes a finishing tape, the finishing tape being adhered to the end of the separator to fix the end of the separator to the outer surface of the winding body, and the finishing tape and the heat dissipation medium are arranged in a staggered pattern on the outer surface of the winding body.

[0017] Preferably, the rectangular cell further includes a second insulating tape, the second insulating tape covering at least a portion of the first corner of the second winding of the two winding groups, Alternatively, the second insulating tape covers at least a portion of the second corner of the second winding of the two winding groups.

[0018] The rectangular cell achieves positional fixation between the two winding groups by arranging the second insulating tape to cover the corner portion (first corner portion or second corner portion) of the second winding group of at least two winding groups, preventing positional displacement of the winding groups during the processing and manufacturing process, facilitating the housing of the windings within the housing, and facilitating subsequent manufacturing processes (e.g., connecting the tabs of the two winding groups).

[0019] Preferably, the rectangular cell further includes a second insulating tape, and at least one end of the second insulating tape extends to the second corner portion of the first winding body of at least one of the winding body groups.

[0020] Since the second insulating tape extends to the second corner portion of the first winding body of the winding body group, the portion of the first winding body of the winding body group that is not covered by the first insulating tape can be tightened, and the sheet and the separator at the side corner portion can be made to adhere more closely.

[0021] Preferably, the rectangular cell further includes a second insulating tape, and at least one end of the second insulating tape extends to the surface of the first insulating tape of at least one of the winding body groups.

[0022] Cover the second insulating tape on the surface of the first insulating tape of the winding body group, structurally reinforce the first insulating tape, and improve the tightening effect of the first insulating tape at the corner portion of the covered winding body.

[0023] Here, according to the method of covering one end of the second insulating tape on the surface of the first insulating tape of one winding body group and extending the other end to the corner portion of the first winding body of another winding body group, it can be adapted to different core combination methods of the winding body, and interference with the already adhered first insulating tapes can be avoided.

[0024] Preferably, the winding body is formed by winding a positive electrode sheet, a negative electrode sheet, and a separator, the separator is sandwiched between the positive electrode sheet and the negative electrode sheet, and along the width direction of the separator, the range of the width D1 of the first insulating tape is 60% - 90% of the width D of the separator.

[0025] By enabling the first insulating tape to closely adhere and cover a large area on the surface of the corner portion of the winding body, the effective area of the first insulating tape and the corner portion of the winding body can be improved, and the first insulating tape can tighten the sheet and the separator of the winding body better.

[0026] Preferably, the first insulating tape includes at least two first sub-insulating tapes, each of the first sub-insulating tapes covers at least a part of the first corner portion of the second winding body, one end of each of the first sub-insulating tapes extends to the first flat portion through the first corner portion of the first winding body, and each of the first sub-insulating tapes is arranged at intervals along the separator width direction of the winding body.

[0027] By arranging a plurality of first sub-insulating tapes to jointly form the first insulating tape, while ensuring the covering area of the first insulating tape on the outer peripheral surface of the winding body, the process difficulty of installing the first insulating tape on each winding body of the winding body group is reduced.

Advantages of the Invention

[0028] The preferred progressive effects of the present invention are as follows. The rectangular cell forms a winding body group from two or more winding body groups, and then by accommodating the two winding body groups in the housing, the overall processing and manufacturing of the rectangular cell becomes easy.

[0029] By arranging the first insulating tape to cover the first corner portion of each winding body in the winding body group, a tightening action is generated on the corner portion of each winding body, and the contact between the sheet and the separator at the first corner portion of the winding body is made close, so that the lithium deposition phenomenon can be improved.

[0030] Rather than extending to the first flat portion of the first winding body, one end of the first insulating tape extends to the surface of the first corner portion of the first winding body through the first corner portion of the second winding body, thereby expanding the covering area of the first insulating tape on the surface of the corner portion of the winding body group, and at the same time avoiding the increase in the overall thickness of the winding body due to the arrangement of the first insulating tape on the flat portion of the winding body. The rectangular cell can accommodate more winding bodies along the first direction, and the energy density can be further improved.

Brief Description of the Drawings

[0031] [Figure 1]This is a schematic diagram of the structure of a rectangular cell according to the first embodiment of the present invention. [Figure 2] This is a schematic diagram of the structure of a wound body according to the first embodiment of the present invention. [Figure 3] This is a surface area distribution diagram of a wound body according to the first embodiment of the present invention. [Figure 4] This is a schematic three-dimensional view of a wound body according to the first embodiment of the present invention. [Figure 5] This is a schematic plan view of a specific method for implementing the first insulating tape according to the first embodiment of the present invention. [Figure 6] Figure 5 is a schematic three-dimensional view of the coiled body group. [Figure 7] This is a schematic plan view of another specific method of implementing the first insulating tape according to the first embodiment of the present invention. [Figure 8] Figure 7 is a schematic three-dimensional view of the coiled body group. [Figure 9] This is a schematic diagram of the installation position of the first insulating tape on the surface of the wound body according to the first embodiment of the present invention. [Figure 10] This is a schematic diagram showing the installation position of the first sub-insulating tape on the surface of the wound body according to the first embodiment of the present invention. [Figure 11] This is a schematic diagram (1) of the processed state of a group of wound bodies according to the first embodiment of the present invention. [Figure 12] This is a schematic diagram (2) of the processed state of the winding body group according to the first embodiment of the present invention. [Figure 13] This is a schematic diagram (3) of the processed state of the winding body group according to the first embodiment of the present invention. [Figure 14] This is a schematic diagram (1) of the structure of a group of wound rectangular cells according to a second embodiment of the present invention. [Figure 15] This is a schematic diagram (2) of the structure of a group of wound rectangular cells according to a second embodiment of the present invention. [Figure 16] This is a schematic diagram of the structure of a group of wound rectangular cells according to a third embodiment of the present invention. [Figure 17] This is a schematic diagram (1) of the structure of a group of wound rectangular cells according to the fourth embodiment of the present invention. [Figure 18]Figure 17 is a schematic three-dimensional view of the coiled body group. [Figure 19] This is a schematic diagram (2) of the structure of a group of wound rectangular cells according to the fourth embodiment of the present invention. [Figure 20] Figure 20 is a schematic diagram (1) of the processing state of a rectangular cell according to the fourth embodiment of the present invention. [Figure 21] This is a schematic diagram (2) of the processing state of a rectangular cell according to the fourth embodiment of the present invention. [Modes for carrying out the invention]

[0032] Preferred embodiments are shown below, and together with the accompanying drawings, the present invention will be described more clearly and completely.

[0033] First Embodiment

[0034] As shown in Figure 1, the rectangular cell 100 includes a housing 10 and a plurality of windings 30 arranged within the housing 10. Each winding 30 is arranged in a stack along a first direction A. A single winding 30 is actually made up of a positive electrode sheet 301, a negative electrode sheet 302, and a separator 303, as shown in Figure 2. The positive electrode sheet 301 and the negative electrode sheet 302 are led out at one end of the winding 30 via a positive electrode tab 3011 and a negative electrode tab 3021, respectively. Here, in order to prevent a short circuit due to contact between the sheet and the negative electrode sheet 302, two separators 303 with a relatively large surface area are used to cover both sides of the sheet, separating the positive electrode sheet 301 and the negative electrode sheet 302 and thus avoiding a short circuit. A finishing tape 80 is also placed on the winding 30. The separator 303 of the winding body 30 is finished by adhering the finishing tape 80 to the end of the separator 303 and fixing the end of the separator 303 to the outer surface of the winding body 30.

[0035] As shown in Figures 3 and 4, along the winding direction B of the winding body 30, the outer surface of the winding body 30 includes two flat sections 304 and two corner sections 305 connected to the opposing ends of the two flat sections 304, respectively. These two corner sections 305 are the first corner section 305a and the second corner section 305b, respectively.

[0036] In the rectangular cell 100 provided by the present invention, in order to facilitate the processing and insertion of each winding body 30 into the housing, each winding body 30 located within the housing 10 is divided into two winding body groups 20. Each winding body group 20 includes at least two stacked winding bodies 30. As shown in Figures 5 and 6, the rectangular cell 100 in this embodiment has four winding bodies 30 and is therefore divided into two winding body groups 20. Each winding body group 20 includes two winding bodies 30 stacked along a first direction A. The two planar portions 304 of each winding body 30 are both perpendicular to the first direction A. Here, among the winding body groups 20, the winding body 30 adjacent to the housing 10 along the first direction A is the first winding body 31, and the two planar portions 304 of the first winding body 31 have a first planar portion 304a adjacent to the housing 10. Among the group of wound bodies 20, the wound body 30 adjacent to another group of wound bodies 20 is the second wound body 32.

[0037] As shown in Figures 5 and 6, taking the winding group 20 located at the top of the figure as an example, the winding group 20 includes a first insulating tape 40, which covers the first corner portion 305a of the second winding 32, and one end of the first insulating tape 40 does not extend to the first flat portion 304a of the first winding 31, but rather extends to the first corner portion 305a of the first winding 31 via the first corner portion 305a of the second winding 32.

[0038] The rectangular cell 100 is formed by creating a winding group 20 with two winding bodies 30, and then housing the two winding group 20 in the housing 10, which facilitates the overall processing and manufacturing of the rectangular cell 100. Here, by placing the first insulating tape 40 on the winding group 20 and covering the first corner portion 305a of each winding body 30 within the winding group 20, the first insulating tape 40 creates a tightening effect on the corner portion 305 of each winding body 30, causing the sheet and separator 303 at the first corner portion 305a of the winding body 30 to adhere closely, thereby improving the lithium deposition phenomenon.

[0039] Furthermore, by extending the first insulating tape 40 along the first direction A to the surface of the first corner portion 305a of the first winding body 31 adjacent to the housing 10, and arranging it with a gap between it and the first flat portion 304a, the covering area of ​​the first insulating tape 40 on the surface of the winding body group 20 can be increased. At the same time, the overall thickness of the winding body 30 can be avoided by placing the first insulating tape 40 on the flat portion 304 of the winding body 30, allowing the rectangular cell 100 to accommodate more winding bodies 30 along the first direction A, thereby further improving the energy density.

[0040] In other embodiments, if a single winding group 20 includes three or more windings 30, the first insulating tape 40 also needs to extend from the first corner portion 305a of the second winding 32 adjacent to another winding group 20 to the first corner portion 305a of the first winding 31 adjacent to the housing 10, so as to contact the first corner portions 305a of all the windings 30 in the winding group 20 simultaneously.

[0041] Specifically, the rectangular cell 100 in Figures 5 and 6 is one specific implementation provided by this embodiment, in which the first insulating tape 40 of both winding group 20 covers the right side of the winding body 30 of the winding group 20. Therefore, in the rectangular cell 100 provided in Figure 5, the first corner portions 305a of the winding bodies 30 of both winding group 20 are located on the right side.

[0042] In other specific implementation methods, as shown in Figures 7 and 8, the right side of the winding body 30 of the winding body group 20 located at the top of the figure is covered with the first insulating tape 40, and the left side of the winding body 30 of the winding body group 20 located at the bottom of the figure is covered with the first insulating tape 40. Therefore, in the rectangular cell 100 provided in Figure 7, the first corner portion 305a of the winding body 30 of the winding body group 20 located at the top of the figure is on the right side, and the first corner portion 305a of the winding body 30 of the winding body group 20 located at the bottom of the figure is on the left side. Of course, the above two specific implementation methods are only schematically shown, and the first insulating tape 40 may be placed on one side of the surface of the winding body group 20 as needed.

[0043] Specifically, in this embodiment, one end of the first insulating tape 40 placed on the second winding body 32 is located at the boundary between the first corner portion 305a and the flat portion 304 of the second winding body 32. By placing one end of the first insulating tape 40 at the boundary between the first corner portion 305a and the flat portion 304 of the second winding body 32, the covering area of ​​the first insulating tape 40 at the corner portion 305 of the winding body 30 can be increased.

[0044] Here, the end of the first insulating tape 40 is positioned at the boundary between the first corner portion 305a and the flat portion 304 of the second winding body 32, and does not extend to the surface of the flat portion 304. This avoids increasing the overall thickness of the winding body 30 by positioning the first insulating tape 40 on the flat portion 304 of the winding body 30, allowing the rectangular cell 100 to accommodate more winding bodies 30 along the first direction A, thereby further improving the energy density. Of course, in other embodiments, the first insulating tape 40 may be positioned at one end of the second winding body 32 and may not extend to the boundary between the first corner portion 305a and the flat portion 304 of the second winding body 32, or it may be extended directly to the flat portion 304 of the second winding body 32 via the first corner portion 305a of the second winding body 32.

[0045] At the same time, the first insulating tape 40, which is positioned at one end of the first winding body 31, is positioned at the boundary between the first corner portion 305a and the first flat portion 304a of the first winding body 31. This prevents an increase in the overall thickness of the winding body 30 due to the placement of the first insulating tape 40 on the first flat portion 304a of the first winding body 31, while simultaneously ensuring sufficient covering area of ​​the first winding body 31 over the first corner portion 305a of the first winding body 31 and improving adhesion with the separator and sheet.

[0046] Specifically, as shown in Figure 9, which is a top view of the first winding body 31 of the winding body group 20 located on the upper side in Figures 5 and 7, it can be seen that the first insulating tape 40 extends to the first corner portion 305a on the right side without extending to the first flat portion 304a on the upper part of the winding body 30. Here, in order to improve the effective area of ​​the corner portion 305 of the winding body 30 and the first insulating tape 40, and to allow the first insulating tape 40 to better fasten the sheet of the winding body 30 and the separator 303, the width D1 of the first insulating tape 40 is set to 60% or more of the width D of the separator 303, thereby ensuring that the first insulating tape 40 can adhere closely to and cover the surface of the winding body 30 over a wide area. At the same time, in order that both sides of the first insulating tape 40 do not extend beyond the separator 303 and affect insertion into the housing, the width D1 of the first insulating tape 40 must be set to 100% or less of the width D of the separator 303. More preferably, the width D1 of the first insulating tape 40 should be set to be 90% or less of the width D of the separator 303.

[0047] Furthermore, the first insulating tape 40 does not necessarily have to be formed from a single wide insulating tape, but may be formed by combining multiple narrow insulating tapes. For example, in another specific embodiment of this invention, the first insulating tape 40 includes two first sub-insulating tapes 41, the two first sub-insulating tapes 41 covering the first corner portion 305a of the second winding 32. As shown in Figure 10, one end of the two first sub-insulating tapes 41 extends to the first corner portion 305a of the first winding 31, and the two first sub-insulating tapes 41 are spaced apart along the width direction C of the separator of the winding 30.

[0048] When the first insulating tape 40 is formed by a plurality of first sub-insulating tapes 41, the sum of the widths of each first sub-insulating tape 41 (D2 + D3 in this embodiment) along the width direction C of the separator must be set to be 60% or more of the width D of the separator 303. Naturally, in other embodiments, by using three or more first sub-insulating tapes 41 to cover the surface of the winding group 20, the objective of tightening the corner portion 305 of the winding group 30 can be achieved by replacing one wide insulating tape with multiple narrow insulating tapes, and the difficulty of processing can be reduced by using multiple narrow insulating tapes.

[0049] Furthermore, in order to improve the heat dissipation effect, a tape with heat dissipation properties may be used for the first insulating tape 40, and the heat dissipation effect may be improved by the first insulating tape 40 covering the surface of the winding group.

[0050] Preferably, the tape thickness of the first insulating tape 40 is in the range of 10 to 60 μm, and the thickness of the adhesive layer is in the range of 5 to 30 μm, and the tape thickness may usually be twice the thickness of the adhesive layer. Furthermore, the first insulating tape 40 should be installed so as to avoid the finishing tape 80 and thermal conductive tape (not shown) on the surface of the winding body 30, so that the tape does not overlap and increase in thickness, occupying more space along the first direction A within the housing.

[0051] The rectangular cell 100 can also be configured to fix the relative position of each winding body 30 within the winding body group 20 by placing the first insulating tape 40 on the first corner portion 305a of all winding bodies 30 in the winding body group 20, and to facilitate connections between the tabs of each winding body 30.

[0052] Specifically, when processing each winding group 20, first, as shown in Figure 11, each winding body 30 within the winding group 20 is stacked along the first direction A, and the positions of each winding body 30 are aligned. Next, as shown in Figure 12, the first insulating tape 40 is attached to the first corner portion 305a of each winding body 30 to fix the position between each winding body 30. Finally, as shown in Figure 13, the positive electrode tabs 3011 of each winding body 30 are brought together and welded, and at the same time, the negative electrode tabs 3021 of the winding bodies 30 are brought together and welded. Here, when forming a winding group 20 with two winding bodies 30 as in this embodiment, the tabs of the winding bodies 30 can be placed near each other, so the difficulty of bringing these tabs together and welding them is reduced, and processing becomes easier.

[0053] Second Embodiment

[0054] This embodiment also provides a prismatic cell 100 having substantially the same structure as the prismatic cell 100 of the first embodiment. The difference is that in this embodiment, the prismatic cell 100 further includes a heat dissipation medium 50. The heat dissipation medium 50 is placed between two adjacent winding groups 20 and is used to improve heat dissipation between the winding groups 20.

[0055] The preferred range for the thermal conductivity of the heat dissipation medium 50 is 0.1 to 1.0. The thermal conductive layer of the heat dissipation medium 50 is a polymer material (e.g., PTFE, PET, GPO, RF, etc.), an inorganic thermal conductive material (e.g., aluminum foil, silicon, etc.), or a metallic material (e.g., a thin metal sheet). Specifically, in this embodiment, the heat dissipation medium 50 is formed by attaching a heat-dissipating insulating tape to the surface of the winding group 20. When the heat dissipation medium 50 is an insulating tape, the thermal conductive layer of the tape is composed of a conventional heat dissipation material such as a polymer material or an inorganic thermal conductive material.

[0056] By placing a heat dissipation medium 50 with thermal conductivity between the winding groups 20, the thermal conductivity between each winding group 20 can be improved, thereby enhancing the overall heat dissipation effect of the rectangular cell 100.

[0057] Specifically, as shown in Figure 14, in this embodiment, the two planar portions 304 of the second winding body 32 include a second planar portion 304b adjacent to another winding body group 20, and an insulating tape-shaped heat dissipation medium 50 is placed between the two second planar portions 304b of these two winding body groups 20.

[0058] Here, the heat dissipation medium 50 should be installed so as not to excessively occupy the space along the first direction A of the winding group 20, avoiding the finishing tape 80 and the thermal conductive tape on the surface of the winding body 30.

[0059] Furthermore, when the heat dissipation medium 50 is placed between the two second planar portions 304b, the connection between the first insulating tape 40 and each winding body 30 can be strengthened by connecting the end of the heat dissipation medium 50 to the end of the first insulating tape 40, thereby improving the clamping ability of each corner portion 305 of the winding body 30. Specifically, the heat dissipation medium 50 and the first insulating tape 40 can be connected in various ways.

[0060] For example, the heat dissipation medium 50 and the first insulating tape 40 may be connected by covering each other. The heat conduction paths of the heat dissipation medium 50 and the first insulating tape 40 are continuous, and the heat from the heat dissipation medium 50 is transferred to the outside through the first insulating tape 40, improving heat dissipation.

[0061] Furthermore, for example, if the heat dissipation medium 50 is in the form of an insulating tape, and the form of the insulating tape used for the heat dissipation medium 50 is the same as that of the first insulating tape 40, then the heat dissipation medium 50 and the first insulating tape 40 of one of the winding body groups 20 can be integrally formed with a single insulating tape. Specifically, as shown in Figure 15, the heat dissipation medium 50 in this embodiment and the first insulating tape 40 of the winding body group 20 located on the upper side in the figure can be integrally formed with a single insulating tape. Specifically, the lower end of the first insulating tape 40 forming the upper winding body group 20 is directly attached to the second flat portion 304b of the second winding body 32 to form the heat dissipation medium 50. In this way, the heat dissipation between the winding bodies 30 can be improved, and at the same time, the connection between the first insulating tape 40 and the winding bodies 30 can be further strengthened.

[0062] Third Embodiment

[0063] This embodiment also provides a rectangular cell 100 having substantially the same structure as the rectangular cell 100 of the first embodiment. The difference is that in this embodiment, when the first insulating tape 40 is placed on the winding group 20 and the first corner portion 305a of each winding 30 of the winding group 20 is tightened, the second corner portion 305b of each winding 30 of the winding group 20 is further tightened. Specifically, as shown in Figure 16, the first insulating tape 40 further covers all of the second corner portions 305b of the winding group 20. Specifically, the portion of the first insulating tape 40 placed on the first flat portion 304a of the first winding 31 is intermittent, and the first insulating tape 40 does not extend to the first flat portion 304a of the first winding 31. By rupturing the first insulating tape 40 at the first flat portion 304a, the first insulating tape 40 relieves stress and avoids stress transmission, assuming that it will wrap around a large area of ​​the surface of the winding body. At the same time, when the first insulating tape 40 wraps around the first corner portion 305a and the second corner portion 305b of each winding body 30, it does not extend to the first flat portion 304a. Therefore, it does not occupy space along the first direction A of the winding body group 20, thus achieving the objective of a compact layout.

[0064] Specifically, in this embodiment, the first corner portion 305a and the second corner portion 305b of the winding body group 20 are wrapped using two tapes, respectively, to form an intermittent first insulating tape 40 on the first flat portion 304a.

[0065] Fourth Embodiment

[0066] This embodiment also provides a rectangular cell 100 having substantially the same structure as the rectangular cell 100 of the first embodiment. The difference is that, based on the rectangular cell 100, it further includes a second insulating tape 70. By arranging the second insulating tape 70 so that both ends cover the two winding groups 20, positional fixation between the two winding groups 20 is achieved, positional displacement of the winding groups 20 during the processing and manufacturing process is prevented, the housing of the windings 30 in the housing 10 is facilitated, and subsequent manufacturing processes (e.g., connecting the tabs of the two winding groups) are facilitated.

[0067] Specifically, as shown in Figure 17, the rectangular cell 100 provided by the first embodiment is used as a base, and the second insulating tape 70 is placed on both sides of the winding group 20. Here, the upper end of the second insulating tape 70 on the left side of the figure covers the surface of the winding 30 of the upper winding group 20 (for example, in this embodiment, it extends to the second corner portion 305b of the first winding 31), and the lower end of the second insulating tape 70 on the left side covers the surface of the first insulating tape 40 of the lower winding group 20. The upper end of the second insulating tape 70 on the right side of the figure covers the surface of the first insulating tape 40 of the upper winding group 20. The lower end of the second insulating tape 70 on the right side covers the surface of the winding 30 of the lower winding group 20 (for example, in this embodiment, it extends to the second corner portion 305b of the first winding 31). As can be seen from Figure 18, the width of the second insulating tape 70 may be different from that of the first insulating tape 40; for example, it may be slightly narrower than the first insulating tape 40.

[0068] Since the second insulating tape 70 extends to the corner portion 305 of the first winding 31 of the winding group 20, the second insulating tape 70 tightens the side corner portion 305 of the winding group 20, allowing the sheet and separator 303 at the side corner portion 305 to be more closely fitted. At the same time, the second insulating tape 70 covers the surface of the first insulating tape 40 of the winding group 20, structurally reinforcing the first insulating tape 40 and improving the tightening effect of the first insulating tape 40 at the corner portion 305 of the covered winding 30. This type of method, in which one end of the second insulating tape 70 is extended to the surface of the first insulating tape 40 of one winding group 20 and the other end is extended to the corner portion 305 of the first winding 31 of another winding group 20, can be adapted to different core combinations of the winding 30 and can avoid interference with already applied first insulating tapes 40.

[0069] Furthermore, as shown in Figure 19, the second insulating tape 70 is placed on both sides of the winding group 20, based on the rectangular cell 100 provided by the third embodiment. Here, the upper end of the second insulating tape 70 on the left side of the figure covers the surface of the first insulating tape 40 of the upper winding group 20, and the lower end of the second insulating tape 70 on the left side covers the surface of the first insulating tape 40 of the lower winding group 20. The upper end of the second insulating tape 70 on the right side of the figure covers the surface of the first insulating tape 40 of the upper winding group 20, and the lower end of the second insulating tape 70 on the right side covers the surface of the first insulating tape 40 of the lower winding group 20.

[0070] Specifically, in other embodiments, the second insulating tape 70 may be selectively configured to cover both sides of the two winding groups 20, or it may cover only one side of the two winding groups 20, and the specific configuration method can be set according to the actual situation. Here, the covering position of the second insulating tape 70, the thickness of the tape, and the thickness of the adhesive layer can refer to the specific installation method of the first insulating tape 40 in the above embodiment.

[0071] By arranging the second insulating tape 70 to cover each of the two winding body groups 20, the positions of the two winding body groups 20 can be fixed, making it easier to carry out subsequent processing steps. Specifically, first, as shown in Figure 20, the two winding body groups 20 are stacked along the first direction A. Next, as shown in Figure 21, the second insulating tape 70 is placed between the two winding body groups 20. The second insulating tape 70 may cover the surface of the winding body 30 of the winding body group 20, or it may cover the surface of the first insulating tape 40 of the winding body group 20, and the specific covering method can be set according to the actual situation. Finally, the two winding body groups 20 fixed by the second insulating tape 70 are inserted into the housing 10, and the subsequent processing steps for the rectangular cell 100 are carried out.

[0072] While specific embodiments of the present invention have been described above, these are merely illustrative examples, and it will be understood by those skilled in the art that the scope of protection of the present invention is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, and all such changes and modifications are within the scope of protection of the present invention. [Industrial applicability]

[0073] The prismatic cell of this invention can be applied in the field of lithium batteries. [Explanation of Symbols]

[0074] 100: Rectangular cell A: 1st direction 10: Housing 20: Cochlear body group 30: Coiled body B: Winding direction 301: Positive electrode sheet 3011: Positive Tab 302: Negative electrode sheet 3021: Negative electrode tab 303: Separator 304: Flat part 304a: 1st plane part 304b: 2nd plane part 305: Corner section 305a: First corner 305b: Second corner 31: Volume 1 Revolving Body 32: Volume 2 Reversal 33: Volume 3 Revolving Body 40: First insulating tape 41: First sub-insulating tape 50: Heat dissipation medium 70: Second insulating tape 80: Finishing Tape

Claims

1. The invention comprises a housing and two groups of windings housed within the housing, each group of windings comprising at least two windings stacked along a first direction, the outer circumferential surface of each winding along the winding direction comprising two planar portions and a first corner portion and a second corner portion connected to the opposing ends of the two planar portions, the two planar portions being perpendicular to the first direction, and in the group of windings, the winding adjacent to the housing along the first direction is the first winding, the two planar portions of the first winding include the first planar portion adjacent to the housing, and in the group of windings, the winding adjacent to another group of windings is the second winding. Each of the aforementioned winding groups further includes a first insulating tape, the first insulating tape covers at least a portion of the first corner of the second winding, and one end of the first insulating tape extends from the first corner of the second winding to the first corner of the first winding. A rectangular cell characterized by the following features.

2. One end of the first insulating tape extends through the first corner portion of the second winding body to the boundary between the first corner portion and the first flat portion of the first winding body. A rectangular cell according to claim 1, characterized in that

3. The other end of the first insulating tape is positioned at the boundary between the first corner portion of the second winding body and the flat portion of the second winding body. A rectangular cell according to claim 1, characterized in that

4. The rectangular cell further includes a heat dissipation medium, which is positioned between the two winding groups. A rectangular cell according to claim 1, characterized in that

5. The two planar portions of the second winding body include a second planar portion adjacent to another group of winding bodies, the heat dissipation medium is positioned between the second planar portions of the two groups of winding bodies, and the heat dissipation medium is connected to the end of the first insulating tape. A rectangular cell according to claim 4, characterized in that it is a rectangular cell.

6. The winding body is formed by winding a positive electrode sheet, a negative electrode sheet, and a separator, the separator is sandwiched between the positive electrode sheet and the negative electrode sheet, and the end of the separator is outside the end of the positive electrode sheet and the negative electrode sheet. The rectangular cell further includes a finishing tape, the finishing tape being adhered to the end of the separator to fix the end of the separator to the outer surface of the winding body, and the finishing tape and the heat dissipation medium being arranged in a staggered pattern on the outer surface of the winding body. A rectangular cell according to claim 4, characterized in that it is a rectangular cell.

7. The rectangular cell further includes a second insulating tape, the second insulating tape covering at least a portion of the first corner of the second winding of the two winding groups, Alternatively, the second insulating tape covers at least a portion of the second corner of the second winding of the two winding groups. A rectangular cell according to any one of claims 1 to 6, characterized in that

8. The rectangular cell further includes a second insulating tape, the second insulating tape extending to a second corner portion of the first winding of at least one of the winding group, and / or, at least one end of the second insulating tape extends to the surface of the first insulating tape of at least one of the winding groups, A rectangular cell according to any one of claims 1 to 6, characterized in that

9. The winding body is formed by winding a positive electrode sheet, a negative electrode sheet, and a separator, the separator is sandwiched between the positive electrode sheet and the negative electrode sheet, and the width D of the first insulating tape is along the width direction of the separator. １ The range is 60% to 90% of the width D of the separator. A rectangular cell according to any one of claims 1 to 6, characterized in that

10. The first insulating tape includes at least two first sub-insulating tapes, each of which covers at least a portion of the first corner of the second winding body, one end of each first sub-insulating tape extends through the first corner of the first winding body to the first flat portion, and each first sub-insulating tape is spaced apart along the separator width direction of the winding body. A rectangular cell according to claim 9, characterized in that it is a rectangular cell.

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