Rectangular cell
The rectangular cell design with insulating strips and optional heat dissipation medium addresses lithium precipitation issues by tightening electrode contacts and improving thermal conductivity, enhancing performance and energy density.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- AESC JAPAN LTD
- Filing Date
- 2025-09-22
- Publication Date
- 2026-04-22
Smart Images
Figure 2026068692000001_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of lithium battery technology, and particularly to rectangular cells.
Background Art
[0002] The core within a rectangular cell is formed by laminating positive and negative electrode sheets and a separator and then winding them. The outer peripheral surface along the winding direction of the core includes a corner region and a planar region. Here, the outer peripheral surface of the core has a curvature in the corner region, and since heat pressing treatment cannot be performed, the contact between the positive and negative electrode sheets and the separator in the corner region is loose and the gap is large. Therefore, during the long-term cycling of the battery cell, lithium precipitation is likely to occur on the surface of the negative electrode sheet located in the corner region, which affects the performance of the battery cell. Also, in current general mass-produced products, due to limitations such as process reasons, it is often the case that a design of laminating a plurality of cores for a rectangular cell of a certain thickness is adopted. As a result, the number of corner regions within the battery cell increases, and the bending angle of the positive and negative electrode sheets and the separator in the corner region becomes larger, and the influence on the performance of the battery cell due to abnormal lithium precipitation becomes increasingly serious.
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 rectangular cell that can overcome the defect that abnormal lithium precipitation easily occurs in the core of a conventional rectangular cell, which affects the performance of the battery cell.
Means for Solving the Problems
[0004] The present invention solves the above-mentioned technical problems through the following technical solution. A rectangular cell includes a housing and two core sets housed within the housing, each of which includes at least two cores stacked along a first direction. Here, the outer circumferential surface of each core along the winding direction includes two planar regions and a first corner region and a second corner region connected to the opposing ends of the two planar regions, respectively, and both of the planar regions are perpendicular to the first direction, and the core adjacent to the housing along the first direction in the core set is designated as the first core, and the two planar regions of the first core include the first planar region adjacent to the housing, and the core adjacent to the other core set in the core set is designated as the second core. Each of the core sets further includes a first insulating strip, the first insulating strip covering at least a portion of the first corner region of the second core, and one end of the first insulating strip extending through the first corner region of the first core to the first planar region.
[0005] The prismatic cell is convenient for the overall processing and manufacturing of the prismatic cell because it is constructed by first forming a core set with two or more cores and then housing two core sets within a housing. In this case, the core set is provided with a tightening effect on the corner region of each core via the first insulating strip by installing a first insulating strip that covers the first corner region of each core. This allows the core to adhere closely to the electrode sheet and separator in the first corner region, improving the lithium deposition phenomenon.
[0006] Furthermore, by extending the first insulating strip along the first direction to the surface of the first planar region of the first core adjacent to the housing, the covering area of the first insulating strip on the surface of the core set is increased, and by using the first core and housing to tighten and fix the portion of the first insulating strip installed in the first planar region, an even better fixing effect can be obtained. At the same time, by extending the first insulating strip along the first direction to the surface of the first planar region of the first core adjacent to the housing, and using the first insulating strip to separate the first core and the housing, the insulating protection effect of the core set can be improved.
[0007] Preferably, one end of the first insulating strip extends through the first corner region of the first core to the second corner region of the first core.
[0008] By extending one end of the first insulating strip through the first corner region of the first core to the second corner region, the covering area of the first insulating strip on the surface of the first core can be improved. As a result, the first insulating strip also provides a direct tightening effect on the second corner region of the first core, allowing for better tightening of the electrode sheets and separators of each core in the core set.
[0009] Preferably, the core set includes at least three cores stacked along the first direction, wherein the core located between the first and second cores in the core set is a third core, and one end of the first insulating strip further extends through a second corner region of the first core to a second corner region of one of the third cores therein.
[0010] By extending the other end of the first insulating strip through the second corner region of the first core and to the second corner region of one of the third cores within it, the covering area of the first insulating strip on the surface of each core in the core set can be improved. The extension of the other end of the first insulating strip to cover more of the second corner region of the core also provides a direct tightening effect to the second corner region covered by the first insulating strip, thereby allowing for better tightening of the electrode sheets and separators of each core in the core set.
[0011] Preferably, one end of the first insulating strip further extends through the second corner region of the first core to the second corner region of the second core.
[0012] The other end of the first insulating strip extends through the second corner region of the first core to the second corner region of the second core, and the first insulating strip covers the second corner region of each core in the core set. This directly provides a tightening effect to the second corner region of each core, resulting in close contact between the electrode sheet and the separator in both corner regions of the core, thereby improving the lithium deposition phenomenon.
[0013] Preferably, the other end of the first insulating strip is installed at the boundary between the first corner region of the second core and the planar region of the second core.
[0014] By placing the other end of the first insulating strip at the boundary between the first corner region and the planar region of the second core, the coverage area of the first insulating strip over the corner region of the core is improved.
[0015] Here, by positioning the end of the first insulating strip at the boundary between the first corner region and the planar region of the second core, and preventing it from extending to the surface of the planar region, it is possible to avoid the first insulating strip being placed in the planar region of the core and increasing the overall thickness dimension of the core. As a result, the prismatic cell can accommodate more cores along the first direction, and the energy density becomes relatively higher.
[0016] Preferably, the rectangular cell further includes a heat dissipation medium, which is placed between the two core sets.
[0017] By installing a heat dissipation medium with thermal conductivity between two adjacent core sets, the thermal conductivity between the core sets is improved, further enhancing the overall heat dissipation capacity of the prismatic cell.
[0018] Preferably, the two planar regions of the second core include a second planar region adjacent to the other core set, the heat dissipation medium is installed between the second planar regions of the two core sets, and the heat dissipation medium is connected to the end of the first insulating strip.
[0019] The thermal conductivity between the two core sets is improved by placing a heat dissipation medium with thermal conductivity between the second planar regions of the two core sets.
[0020] By connecting the heat dissipation medium to the end of the first insulating strip, the connection relationship between the first insulating strip and each core can be strengthened, improving the ability to tighten each corner region of the core.
[0021] At the same time, by connecting the heat dissipation medium and the first insulating strip, and making the heat conduction path between the heat dissipation medium and the first insulating strip continuous, the heat from the heat dissipation medium is transferred to the outside through the first insulating strip, thereby further enhancing the heat dissipation capacity.
[0022] Preferably, the core is formed by winding a positive electrode sheet, a negative electrode sheet, and a separator, the separator being sandwiched between the positive electrode sheet and the negative electrode sheet, and the ends of the separator extending beyond the ends of the positive electrode sheet and the negative electrode sheet. The rectangular cell further includes a finishing adhesive tape, the finishing adhesive tape being attached to the ends of the separator and fixing the ends of the separator to the outer circumferential surface of the core, and the finishing adhesive tape and the heat dissipation medium being positioned offset from each other on the outer circumferential surface of the core.
[0023] Preferably, the rectangular cell further includes a second insulating strip, and the second insulating strip covers at least a part of the first corner region of the second core of the two core sets. Alternatively, the second insulating strip covers at least a part of the second corner region of the second core of the two core sets.
[0024] By providing the second insulating strip on the rectangular cell to cover at least the corner portion (the first corner region or the second corner region) of the second core of the two core sets, the position fixing between the two core sets is realized, and it is convenient for accommodating the core in the housing to prevent displacement during the processing and manufacturing process between the core sets, and it is also convenient for implementing subsequent manufacturing processes (for example, connecting the tabs of the two sets of core sets).
[0025] Preferably, the rectangular cell further includes a second insulating strip, and at least one end of the second insulating strip extends to at least the second corner region of the first core of at least one of the core sets.
[0026] Since the second insulating strip extends to the second corner region of the first core of the core set, the portion of the first core of the core set that is not covered by the first insulating strip is tightened through the second insulating strip, so that the electrode sheet and the separator in the corner region on that side can be further adhered closely.
[0027] Preferably, the rectangular cell further includes a second insulating strip, and at least one end of the second insulating strip extends to at least the surface of the first insulating strip of at least one of the core sets.
[0028] Since the second insulating strip covers the surface of the first insulating strip of the core set, the structure of the first insulating strip is strengthened, and the tightening effect on the corner region of the core covered by the first insulating strip is improved.
[0029] Here, for the solution where one end of the second insulating strip covers the surface of the first insulating strip of one core set and the other end extends to the corner region of the first core of another core set, since it can adapt to different core connection solutions of the cores, interference between the already adhered first insulating strips can be prevented.
[0030] Preferably, the core 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. Along the width direction of the separator, the value range of the width D1 of the first insulating strip is 60% - 90% of the width D of the separator.
[0031] Since the first insulating strip adheres over a large area to cover the surface of the corner region of the core, the working area between the first insulating strip and the corner region of the core is improved. Therefore, the first insulating strip can more tightly compress the electrode sheet and the separator of the core.
[0032] Preferably, the first insulating strip includes at least two first sub - insulating strips. Each of the first sub - insulating strips covers at least a part of the first corner region of the second core, and one end of each of the first sub - insulating strips passes through the first corner region of the first core and extends to the first planar region. Each of the first sub - insulating strips is arranged at intervals along the width direction of the separator of the core.
[0033] By installing a plurality of first sub - insulating strips to jointly form the first insulating strip, while ensuring the covering area of the first insulating strip on the outer peripheral surface of the core, the difficulty of the process of installing the first insulating strip on each core of the core set is reduced.
Advantages of the Invention
[0034] The desirable advancements of the present invention are as follows: The prismatic cell is convenient for the overall processing and manufacturing of the prismatic cell because it is constructed by first forming a core set with two or more cores and then housing two core sets within a housing.
[0035] By installing a first insulating strip to cover the first corner region of each core in the core set, a tightening effect is brought about for the corner region of each core, so that the core adheres closely to the electrode sheet and separator in the first corner region, and the lithium deposition phenomenon can be improved.
[0036] By extending the first insulating strip along the first direction to the surface of the first planar region of the first core adjacent to the housing, the covering area of the first insulating strip on the surface of the core set is increased, and by using the first core and housing to tighten and fix the portion of the first insulating strip installed in the first planar region, an even better fixing effect can be obtained. [Brief explanation of the drawing]
[0037] [Figure 1] This is a schematic diagram of the structure of a rectangular cell according to Embodiment 1 of the present invention. [Figure 2] This is a schematic diagram of the core structure of Embodiment 1 of the present invention. [Figure 3] This is a distribution diagram of the surface area of the core in Embodiment 1 of the present invention. [Figure 4] This is a schematic three-dimensional view of the core of Embodiment 1 of the present invention. [Figure 5] This is a schematic plan view of one specific embodiment of the first insulating strip of Embodiment 1 of the present invention. [Figure 6] Figure 5 is a schematic diagram of the core set in three dimensions. [Figure 7] This is a schematic plan view of another specific embodiment of the first insulating strip of Embodiment 1 of the present invention. [Figure 8] Figure 7 is a schematic diagram of the core set in three dimensions. [Figure 9] This is a schematic diagram showing the installation position of the first insulating strip on the core surface of Embodiment 1 of the present invention. [Figure 10] This is a schematic diagram showing the installation position of the first sub-insulating strip on the core surface of Embodiment 1 of the present invention. [Figure 11] This is a schematic diagram (1) of the processed state of the core set of Embodiment 1 of the present invention. [Figure 12] This is a schematic diagram (2) of the processed state of the core set according to Embodiment 1 of the present invention. [Figure 13] This is a schematic diagram (3) of the processed state of the core set according to Embodiment 1 of the present invention. [Figure 14] This is a schematic diagram of the structure of the core set of a rectangular cell according to Embodiment 2 of the present invention. [Figure 15] This is a schematic diagram of the structure of the core set of a rectangular cell according to Embodiment 3 of the present invention. [Figure 16] This is a schematic diagram of the structure of the core set of a rectangular cell according to Embodiment 4 of the present invention. [Figure 17] This is a schematic diagram (1) of the structure of the core set of a rectangular cell according to Embodiment 5 of the present invention. [Figure 18] This is a schematic diagram (2) of the structure of the core set of a rectangular cell according to Embodiment 5 of the present invention. [Figure 19] This is a schematic diagram of the structure of the core set of a rectangular cell according to Embodiment 6 of the present invention. [Figure 20] This is a schematic diagram (1) of the structure of the core set of a rectangular cell according to Embodiment 7 of the present invention. [Figure 21] Figure 20 is a schematic diagram of the core set in three dimensions. [Figure 22] This is a schematic diagram (2) of the structure of the core set of a rectangular cell according to Embodiment 7 of the present invention. [Figure 23] This is a schematic diagram (1) of the processed state of the rectangular cell according to Embodiment 7 of the present invention. [Figure 24] This is a schematic diagram (2) of the processed state of the rectangular cell according to Embodiment 7 of the present invention. [Modes for carrying out the invention]
[0038] The present invention will be explained more clearly and completely below, with reference to preferred embodiments and in conjunction with the accompanying drawings.
[0039] Example 1
[0040] As shown in Figure 1, the rectangular cell 100 includes a housing 10 and a plurality of cores 30 installed within the housing 10, with each core 30 stacked along a first direction A. A single core 30 is actually formed by winding a positive electrode sheet 301, a negative electrode sheet 302, and a separator 303, as shown in Figure 2, with the positive electrode sheet 301 and the negative electrode sheet 302 being pulled out at one end of the core 30 by their respective positive electrode tabs 3011 and negative electrode tabs 3021. Here, in order to avoid contact short circuits between the electrode sheets and the negative electrode sheet 302, the positive electrode sheet 301 and the negative electrode sheet 302 are separated and short circuits are avoided by covering both the positive and negative sides of the electrode sheet with two relatively large separators 303. Furthermore, a finishing adhesive tape 80 is installed on the core 30, and the finishing adhesive tape 80 is attached to the ends of the separators 303, fixing the ends of the separators 303 to the outer circumferential surface of the core 30.
[0041] As shown in Figures 3 and 4, along the winding direction B of the core 30, the outer surface of the core 30 each includes two planar regions 304 and two corner regions 305 connected to the opposing ends of the two planar regions 304, respectively, and these two corner regions 305 are designated as the first corner region 305a and the second corner region 305b.
[0042] In the rectangular cell 100 provided by the present invention, in order to facilitate the processing of each core 30 and its installation into the housing, the cores 30 to be installed in the housing 10 are divided into two core sets 20, and each core set 20 includes at least two stacked cores 30. As shown in Figures 5 and 6, the rectangular cell 100 in this embodiment has four cores 30, so it is divided into two core sets 20, and each core set 20 includes two cores 30 stacked along the first direction A, and the two planar regions 304 of each core 30 are both perpendicular to the first direction A. Here, in the core set 20, the core 30 adjacent to the housing 10 along the first direction A is designated as the first core 31, and the two planar regions 304 of the first core 31 include the first planar region 304a adjacent to the housing 10, and the core 30 adjacent to another core set 20 in the core set 20 is designated as the second core 32.
[0043] As shown in Figures 5 and 6, taking the core set 20 located at the top of the figure as an example, the core set 20 includes a first insulating strip 40, the first insulating strip 40 covers the first corner region 305a of the second core 32, and one end of the first insulating strip 40 extends through the first corner region 305a of the first core 31 to the first planar region 304a.
[0044] The rectangular cell 100 is convenient for overall processing and manufacturing because it is constructed by first forming a core set 20 with two cores 30 and then housing the two core sets 20 in a housing 10. In this case, the core set 20 is provided with a first insulating strip 40 to cover the first corner region 305a of each core 30 within the core set 20, thereby creating a tightening effect on the corner region 305 of each core 30 via the first insulating strip 40. This allows the core 30 to adhere closely to the electrode sheet and separator 303 in the first corner region 305a, improving the lithium deposition phenomenon.
[0045] Furthermore, by extending the first insulating strip 40 along the first direction A to the surface of the first planar region 304a of the first core 31 adjacent to the housing 10, the covering area of the first insulating strip 40 on the outer surface of the core set 20 is increased, and by using the first core 31 and the housing 10 to tighten and fix the portion of the first insulating strip 40 installed in the first planar region 304a, an even better fixing effect can be obtained.
[0046] At the same time, by extending the first insulating strip 40 along the first direction A to the surface of the first planar region 304a of the first core 31 adjacent to the housing 10, and by using the first insulating strip 40 to separate the first core 31 from the housing 10, the insulating protection effect of the core set 20 can be improved.
[0047] In other embodiments, where a single core set 20 includes three or more cores 30, the first insulating strip 40 should extend from the first corner region 305a of the second core 32 adjacent to the other core set 20 to the first corner region 305a and first planar region 304a of the first core 31 adjacent to the housing 10, so as to make simultaneous contact with the first corner regions 305a of all cores 30 in the core set 20.
[0048] To be more specific, the rectangular cell 100 in Figures 5 and 6 is a specific embodiment provided by this embodiment, in which the first insulating strip 40 of the two core sets 20 both cover the right side of the core 30 of the core set 20. Therefore, in the rectangular cell 100 provided in Figure 4, the first corner region 305a of the core 30 of the two core sets 20 is on the right side in both cases.
[0049] On the other hand, in other specific implementations, as shown in Figures 7 and 8, the core 30 of the upper core set 20 in the figure is covered on the right side with the first insulating strip 40, and the core 30 of the lower core set 20 in the figure is covered on the left side with the first insulating strip 40. Therefore, in the rectangular cell 100 provided in Figure 7, the first corner region 305a of the core 30 of the upper core set 20 in the figure is on the right side, and the first corner region 305a of the core 30 of the lower core set 20 is on the left side. Of course, the two specific implementations described above are merely for illustrative purposes, and the first insulating strip 40 can be installed on the surface of one side of the core set 20 as needed.
[0050] Specifically, in this embodiment, the first insulating strip 40 is installed at the boundary between the first corner region 305a and the planar region 304 of the second core 32 at one end of the second core 32. By installing one end of the first insulating strip 40 at the boundary between the first corner region 305a and the planar region 304 of the second core 32, the covering area of the first insulating strip 40 over the corner region 305 of the core 30 can be improved.
[0051] Here, by placing the end of the first insulating strip 40 at the boundary between the first corner region 305a and the planar region 304 of the second core 32 and preventing it from extending to the surface of the planar region 304, it is possible to avoid the first insulating strip 40 being placed in the planar region 304 of the core 30 and increasing the overall thickness dimension of the core 30. As a result, the rectangular cell 100 can accommodate more cores 30 along the first direction A, and the energy density becomes relatively higher. Of course, in other embodiments, the first insulating strip 40 may be placed at one end of the second core 32 and not extend to the boundary between the first corner region 305a and the planar region 304 of the second core 32, or it may pass through the first corner region 305a and extend directly to the planar region 304.
[0052] Specifically, as shown in Figure 9, Figure 9 is a top view of the first core 31 of the core set 20 located above Figures 5 and 7. As can be seen from the figure, the first insulating strip 40 extends through the first corner region 305a on the right side to the first planar region 304a at the top of the core 30. Here, in order to improve the working area of the first insulating strip 40 and the corner region 305 of the core 30 so that the first insulating strip 40 can better constrict the electrode sheet and separator 303 of the core 30, the width D1 of the first insulating strip 40 should be 60% or more of the width D of the separator 303, thereby ensuring that the first insulating strip 40 adheres over a wide area and covers the surface of the core 30. At the same time, the width D1 of the first insulating strip 40 should be 100% or less of the width D of the separator 303, thereby avoiding both sides of the first insulating strip 40 extending beyond the separator 303 and affecting insertion into the housing. More preferably, the width D1 of the first insulating strip 40 should be 90% or less of the width D of the separator 303.
[0053] At the same time, in order to further improve the covering area of the first insulating strip 40 on the surface of the first planar region 304a and to ensure the reliability of the connection between the first insulating strip 40 and the first core 31, the length L1 of the first insulating strip 40 on the first planar region 304a should be 20% or more of the length L of the separator 303 on the first planar region 304a, thereby ensuring that the first insulating strip 40 adheres over a wide area and covers the surface of the first planar region 304a of the first core 31. At the same time, under the premise of ensuring the reliability of the connection, the length L1 of the first insulating strip 40 on the first planar region 304a may be 50% or less of the length L of the separator 303 on the first planar region 304a.
[0054] Furthermore, the first insulating strip 40 does not necessarily have to be formed by a single relatively wide insulating strip, but may be formed jointly by a plurality of relatively narrow insulating strips. For example, in another specific embodiment of this model, the first insulating strip 40 includes two first sub-insulating strips 41, the two first sub-insulating strips 41 covering the first corner region 305a of the second core 32. As shown in Figure 10, one end of each of the two first sub-insulating strips 41 extends through the first corner region 305a of the first core 31 to the first planar region 304a, and these two first sub-insulating strips 41 are spaced apart along the separator width direction C of the core 30.
[0055] In a situation where a first insulating strip 40 is jointly formed by multiple first sub-insulating strips 41, the sum of the widths of each first sub-insulating strip 41 (D2 + D3 in this embodiment) along the separator width direction C should be 60% or more of the width D of the separator 303. Naturally, in other embodiments, the objective of constricting the corner region 305 of the core 30 may be achieved by employing three or more first sub-insulating strips 41, each covering the surface of the core set 20, and by replacing multiple relatively narrow insulating strips with a single relatively wide insulating strip, and the difficulty of processing can be reduced by employing multiple relatively narrow insulating strips.
[0056] Furthermore, in order to improve the heat dissipation effect, the first insulating strip 40 may be made of adhesive tape with heat dissipation capabilities, so that the first insulating strip 40 covering the surface of the core set can help dissipate heat.
[0057] Preferably, the thickness of the adhesive tape of the first insulating strip 40 is in the range of 10 to 60 μm, the thickness of the adhesive layer is in the range of 5 to 30 μm, and the thickness of the adhesive tape may usually be twice the thickness of the adhesive layer. Furthermore, the installation of the first insulating strip 40 should avoid the finishing adhesive tape 80 and thermal conductive adhesive tape (not shown) on the surface of the core 30, thereby avoiding the adhesive tape from accumulating and increasing in thickness, which would occupy more space along the first direction A within the housing.
[0058] The rectangular cell 100 is convenient for making connections between the tabs of each core 30 because it can also fix the relative position of each core 30 within the core set 20 by installing the first insulating strip 40 in the first corner region 305a of all cores 30 of the core set 20 using the first insulating strip 40.
[0059] To explain in detail, when processing each core set 20, first, as shown in Figure 11, each core 30 in the core set 20 is stacked together along the first direction A, and the positions of each core 30 are aligned. Then, as shown in Figure 12, the first insulating strip 40 is attached to the first corner region 305a of each core 30 to fix the position between each core 30. Finally, as shown in Figure 13, the positive electrode tabs 3011 of each core 30 are welded together, and at the same time, the negative electrode tabs 3021 of the cores 30 are welded together. Here, in a situation where the core set 20 is composed of two cores 30, similar to this embodiment, the difficulty of welding these tabs together can be reduced by positioning the tabs of the cores 30 close to the other core 30, which is convenient for processing.
[0060] Example 2
[0061] This embodiment further provides a rectangular cell 100 whose structure is substantially the same as that of the rectangular cell 100 of Embodiment 1, but differs in that, as shown in Figure 14, the end of the first insulating strip 40 of the core set 20 in this embodiment further passes through the first corner region 305a and the first planar region 304a of the first core 31, and further extends to the second corner region 305b of the first core 31. This structural installation method improves the covering area of the first insulating strip 40 on the surface of the first core 31, so that the first insulating strip 40 also provides a direct tightening effect on the second corner region 305b of the first core 31, and the electrode sheet and separator 303 of each core 30 in the core set 20 can be tightened more effectively. Specifically, in this embodiment, the end of the first insulating strip 40 extends to the boundary between the second corner region 305b and the planar region 304 of the first core 31, covering the entire second corner region 305b of the first core 31 along the winding direction B.
[0062] Specifically, in this embodiment, the covering area of the first insulating strip 40 on the surface of the first planar region 304a of the first core 31 is made even larger than in Embodiment 1, and the insulating protection effect of the core set 20 is improved by using the first insulating strip 40 to separate the first core 31 from the housing 10.
[0063] Here, Figure 14 shows only the arrangement of the first insulating strip 40 of the upper core set 20 in the rectangular cell 100 of this embodiment, and does not show the lower core set 20. However, the first insulating strip 40 of the lower core set 20 can be installed according to the actual situation.
[0064] Example 3
[0065] This embodiment further provides a rectangular cell 100 whose structure is substantially the same as that of the rectangular cell 100 of Embodiment 2, the difference being that, in a situation where a single core set 20 contains three or more cores 30, the core 30 installed between the first core 31 and the second core 32 in the core set 20 is designated as the third core 33. As shown in Figure 15, in this embodiment, the end of the first insulating strip 40 further extends through the second corner region 305b of the first core 31 to the second corner region 305b of the third core 33. This structural installation method improves the coverage area of the first insulating strip 40 on the surface of each core 30 in the core set 20. By extending the other end of the first insulating strip 40 to cover the second corner regions 305b of even more cores 30, a direct tightening effect is also brought to the second corner regions 305b covered by the first insulating strip 40, allowing for better tightening of the electrode sheets and separators 303 of each core 30 in the core set 20. In this embodiment, the end of the first insulating strip 40 is extended to the boundary between the second corner region 305b and the planar region 304 of the third core 33, thereby covering as wide an area of the second corner region 305b of the third core 33 as possible. In this embodiment, the first insulating strip 40 covers the surface of the first planar region 304a of the first core 31, and by using the first insulating strip 40 to separate the first core 31 from the housing 10, the insulating protection effect of the core set 20 is improved.
[0066] Specifically, in this embodiment, the core set 20 is composed of three cores 30, so in this situation, there is only one third core 33 in the core set 20. In other embodiments, when the core set 20 is composed of four or more cores 30, there should be multiple third cores 33 in the core set 20, and in this situation, the end of the first insulating strip 40 can extend to the second corner region 305b of one of the third cores 33, but to which specific third core 33 it extends can be set according to the actual situation.
[0067] Furthermore, Figure 15 only shows the arrangement of the first insulating strip 40 of the upper core set 20 in the rectangular cell 100 of this embodiment, and does not show the lower core set 20. However, the first insulating strip 40 of the lower core set 20 can be installed according to the actual situation.
[0068] Example 4
[0069] This embodiment further provides a rectangular cell 100 whose structure is substantially the same as that of the rectangular cell 100 of Embodiment 2, but differs in that, as shown in Figure 16, the first insulating strip 40 of the core set 20 in this embodiment further passes through the second corner region 305b of the first core 31 and extends to the second corner region 305b of the second core 32. This structural installation method improves the covering area of the first insulating strip 40 on the surface of the first core 31, and because the first insulating strip 40 covers the second corner region 305b of each core 30 in the core set 20, it also provides a direct binding effect to the second corner region 305b of each core 30, so that the electrode sheet and separator 303 in both corner regions 305 of the core 30 are in close contact, and the lithium deposition phenomenon can be improved.
[0070] Specifically, in this embodiment, the first insulating strip 40 covers the surface of the first planar region 304a of the first core 31, and by using the first insulating strip 40 to separate the first core 31 from the housing 10, the insulating protection effect of the core set 20 is improved.
[0071] In this embodiment, the end of the first insulating strip 40 is extended to the boundary between the second corner region 305b and the planar region 304 of the first core 31, thereby covering as wide an area as possible of the second corner region 305b of the first core 31.
[0072] Here, Figure 16 only shows the arrangement of the first insulating strip 40 of the upper core set 20 in the rectangular cell 100 of this embodiment, and does not show the lower core set 20. However, the first insulating strip 40 of the lower core set 20 can be installed according to the actual situation.
[0073] Example 5
[0074] This embodiment further provides a prismatic cell 100 whose structure is substantially the same as that of the prismatic cell 100 of Embodiment 1, the difference being that in this embodiment the prismatic cell 100 further includes a heat dissipation medium 50, which is placed between two adjacent core sets 20 to improve the heat dissipation capacity between the core sets 20.
[0075] The preferred range for the thermal conductivity of the heat dissipation medium 50 is between 0.1 and 1.0, and the thermal conductive layer of the heat dissipation medium 50 may be a polymer material (e.g., PTFE, PET, GPO, RF, etc.), an inorganic thermal conductive material (e.g., aluminum foil, silicone gel, etc.), or a metallic material (e.g., a thin metal sheet). Specifically, in this embodiment, the heat dissipation medium 50 is formed by using an insulating adhesive tape with heat dissipation capabilities and attaching it to the surface of the core set 20. When the heat dissipation medium 50 is an insulating adhesive tape, the thermal conductive layer of the adhesive tape is composed of a conventional heat dissipation material such as a polymer material or an inorganic thermal conductive material.
[0076] By installing a heat dissipation medium 50 with thermal conductivity between the core sets 20, the thermal conductivity between the core sets 20 can be improved, thereby improving the overall heat dissipation capacity of the prismatic cell 100.
[0077] To explain in more detail, as shown in Figure 17, in this embodiment, the second core 32 has two planar regions 304, including a second planar region 304b adjacent to another core set 20, and the heat dissipation medium 50 in the form of insulating adhesive tape is installed between the two second planar regions 304b of these two core sets 20.
[0078] Here, the installation of the heat dissipation medium 50 should avoid the surface finishing adhesive tape 80 and thermal conductive adhesive tape of the core 30, thereby avoiding excessive occupancy of the space along the first direction A of the core set 20.
[0079] Furthermore, when the heat dissipation medium 50 is installed between the two second planar regions 304b, connecting the end of the heat dissipation medium 50 to the end of the first insulating strip 40 strengthens the connection between the first insulating strip 40 and each core 30, improving the ability of the core 30 to tighten against each corner region 305. Specifically, the method of connecting the heat dissipation medium 50 and the first insulating strip 40 can vary. For example, by connecting them in a way that covers each other, and making the heat conduction paths of the heat dissipation medium 50 and the first insulating strip 40 continuous, the heat from the heat dissipation medium 50 is transferred to the outside through the first insulating strip 40, thereby further increasing the heat dissipation capacity.
[0080] Furthermore, for example, in a situation where the heat dissipation medium 50 employs an insulating adhesive tape format, if the insulating adhesive tape format employed by the heat dissipation medium 50 is the same as that of the first insulating strip 40, the heat dissipation medium 50 and the first insulating strip 40 of one of the core sets 20 can be jointly formed by a single insulating strip. Specifically, as shown in Figure 18, the heat dissipation medium 50 in this embodiment is jointly formed by the first insulating strip 40 of the upper core set 20 in the figure and a single insulating adhesive tape. To explain in more detail, the lower end forming the first insulating adhesive tape 40 of the upper core set 20 is directly attached to the second planar region 304b of the second core 32 to form the heat dissipation medium 50. By doing so, the heat dissipation capacity between the cores 30 can be improved, and the connection relationship between the first insulating strip 40 and the cores 30 can be further strengthened.
[0081] Example 6
[0082] This embodiment further provides a rectangular cell 100 whose structure is almost the same as that of the rectangular cell 100 of Embodiment 4, but the difference is that in this embodiment, a first insulating strip 40 is installed on the core set 20, and in the situation where the first corner region 305a and the second corner region 305b of each core 30 of the core set 20 are tightly bound, specifically as shown in Figure 19, the portion of the first insulating strip 40 installed on the first planar region 304a is discontinuous. By cutting the first insulating strip 40 at this location, stress is released under the premise that the first insulating strip 40 covers the surface of the core over a wide area, and in order to avoid the transmission of stress, the contact between the electrode sheet and the separator 303 of each core 30 is further tightened, further improving the lithium deposition phenomenon. Specifically, in this embodiment, a discontinuous first insulating strip 40 is formed on the first planar region 304a by covering the first corner region 305a side and the second corner region 305b side of the core 30 with two adhesive tapes, respectively.
[0083] Example 7
[0084] This embodiment further provides a rectangular cell 100 whose structure is substantially the same as that of the rectangular cell 100 of Embodiment 1, but differs in that it further includes a second insulating strip 70 based on the rectangular cell 100, the ends of which each cover two core sets 20 thereby achieving positional fixation between the two core sets 20 and preventing misalignment between the core sets 20 during the manufacturing process, making it convenient to house the core 30 within the housing 10 and convenient for subsequent manufacturing processes (e.g., connecting the tabs of the two sets of core sets 20).
[0085] Specifically, as shown in Figures 20 and 21, a second insulating strip 70 is installed on each side of the core set 20, based on the rectangular cell 100 provided by Embodiment 1. Here, the second insulating strip 70 located on the left side in the figure has its upper end covering the surface of the core 30 of the upper core set 20 (for example, in this embodiment, it extends to the second corner region 305b of the first core 31), and the lower end of the second insulating strip 70 on the left side covers the surface of the first insulating strip 40 of the lower core set 20. Also, the second insulating strip 70 located on the right side in the figure has its upper end covering the surface of the first insulating strip 40 of the upper core set 20, and the lower end of the second insulating strip 70 on the right side covers the surface of the core 30 of the lower core set 20 (for example, in this embodiment, it extends to the second corner region 305b of the first core 31). As can be seen from Figure 21, the width of the second insulating strip 70 may be different from that of the first insulating strip 40, for example, it may be slightly narrower than the first insulating strip 40.
[0086] By extending the second insulating strip 70 to the corner region 305 of the first core 31 of the core set 20, the corner region 305 on that side of the core set 20 is tightened via the second insulating strip 70, further strengthening the contact between the electrode sheet and the separator 303 in that corner region 305. At the same time, the second insulating strip 70 covers the surface of the first insulating strip 40 of the core set 20, thereby reinforcing the structure of the first insulating strip 40 and improving the tightening effect of the first insulating strip 40 on the corner region 305 of the covered core 30. This method, in which one end of the second insulating strip 70 is extended to the surface of the first insulating strip 40 of one core set 20 and the other end is extended to the corner region 305 of the first core 31 of another core set 20, can be adapted to different core bonding schemes of the core 30, thus avoiding interference between already attached first insulating strips 40.
[0087] Furthermore, as shown in Figure 22, a second insulating strip 70 is installed on both sides of the core set 20, based on the rectangular cell 100 provided by Example 6. Here, the upper end of the second insulating strip 70 located on the left side of the figure covers the surface of the first insulating strip 40 of the upper core set 20, and the lower end of the second insulating strip 70 on the left side covers the surface of the first insulating strip 40 of the lower core set 20. Also, the upper end of the second insulating strip 70 located on the right side of the figure covers the surface of the first insulating strip 40 of the upper core set 20, and the lower end of the second insulating strip 70 on the right side covers the surface of the first insulating strip 40 of the lower core set 20.
[0088] More specifically, in other embodiments, the second insulating strip 70 can choose to cover both sides of each of the two core sets 20, or to cover only one side of each core set 20. The specific installation method can be set according to the actual situation. Here, the covering position of the second insulating strip 70, the thickness of the adhesive tape, and the thickness of the adhesive layer can be determined by referring to the specific installation method of the first insulating strip 40 in the embodiments described above.
[0089] By installing the second insulating strip 70 and covering each of the two core sets 20, the position between the two core sets 20 is fixed, which is convenient for subsequent processing steps. Specifically, first, as shown in Figure 23, the two core sets 20 are stacked together along the first direction A. Then, as shown in Figure 24, the space between the two core sets 20 is covered with the second insulating strip 70. The second insulating strip 70 may cover the surface of the core 30 of the core set 20, or it may cover the surface of the first insulating strip 40 of the core set 20, but the specific covering method can be set according to the actual situation. Finally, the two core sets 20 fixed together by the second insulating strip 70 are placed into the housing 10, and the subsequent processing steps for the rectangular cell 100 are carried out.
[0090] The specific embodiments of the present invention have been described above. However, those skilled in the art should understand that this is merely an example, and the protection scope of the present invention is limited by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments on the premise of not departing from the principle and essence of the present invention, and all these changes and modifications shall be included in the protection scope of the present invention.
Industrial Applicability
[0091] The square cell of the present invention can be applied in the field of lithium battery technology.
Explanation of Signs
[0092] 100 Square cell A First direction 10 Housing 20 Core set 30 Core B Winding direction 301 Positive electrode sheet 3011 Positive electrode tab 302 Negative electrode sheet 3021 Negative electrode tab 303 Separator 304 Plane region 304a First plane region 304b Second plane region 305 Corner region 305a First corner region 305b Second corner region 31 First core 32 Second core 33 Third core 40 First insulating strip 41 First sub-insulating strip 50 Heat dissipation medium 70 Second insulating strip 80 Finishing adhesive tape
Claims
1. The system includes a housing and two core sets housed within the housing, Each core set includes at least two cores stacked along a first direction, the outer surface of each core along the winding direction each includes two planar regions and a first corner region and a second corner region connected to the opposing ends of the two planar regions, and both of the two planar regions are perpendicular to the first direction. In the core set, the core adjacent to the housing along the first direction is designated as the first core, and the two planar regions of the first core include the first planar region adjacent to the housing, and in the core set, the core adjacent to another core set is designated as the second core. Each of the core sets further includes a first insulating strip, the first insulating strip covering at least a portion of the first corner region of the second core, and one end of the first insulating strip extending through the first corner region of the first core to the first planar region. A rectangular cell characterized by the following features.
2. One end of the first insulating strip extends through the first corner region of the first core to the second corner region of the first core. A rectangular cell according to claim 1, characterized in that
3. The core set includes at least three cores stacked along the first direction, wherein the core located between the first core and the second core in the core set is a third core, and one end of the first insulating strip further extends through the second corner region of the first core to the second corner region of one of the third cores. A rectangular cell according to claim 2, characterized in that
4. One end of the first insulating strip further extends through the second corner region of the first core to the second corner region of the second core. A rectangular cell according to claim 2, characterized in that
5. The other end of the first insulating strip is installed at the boundary between the first corner region of the second core and the planar region of the second core. A rectangular cell according to claim 1, characterized in that
6. The rectangular cell further includes a heat dissipation medium, which is placed between the two core sets. A rectangular cell according to claim 1, characterized in that
7. The two planar regions of the second core include a second planar region adjacent to another set of cores, the heat dissipation medium is installed between the second planar regions of the two sets of cores, and the heat dissipation medium is connected to the end of the first insulating strip. A rectangular cell according to claim 6, characterized in that it is a rectangular cell.
8. The core 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 extends beyond the ends of the positive electrode sheet and the negative electrode sheet. The rectangular cell further includes a finishing adhesive tape, the finishing adhesive tape being attached to the end of the separator to fix the end of the separator to the outer surface of the core, and the finishing adhesive tape and the heat dissipation medium being positioned offset from each other on the outer surface of the core. A rectangular cell according to claim 6, characterized in that it is a rectangular cell.
9. The rectangular cell further includes a second insulating strip, the second insulating strip covering at least a portion of the first corner region of the second core of the two core sets, Alternatively, the second insulating strip covers at least a portion of the second corner region of the second core of the two core sets. A rectangular cell according to any one of claims 1 to 8, characterized in that
10. The rectangular cell further includes a second insulating strip, at least one end of the second insulating strip extending to a second corner region of the first core of at least one of the core sets, and / or, at least one end of the second insulating strip extends to the surface of the first insulating strip of at least one of the core sets. A rectangular cell according to any one of claims 1 to 8, characterized in that
11. The core 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 of the first insulating strip along the width direction of the separator is in the range of 60% to 90% of the width of the separator. A rectangular cell according to any one of claims 1 to 8, characterized in that
12. The first insulating strip includes at least two first sub-insulating strips, each of which covers at least a portion of the first corner region of the second core, and one end of each first sub-insulating strip extends through the first corner region of the first core to the first planar region, and each first sub-insulating strip is spaced apart along the separator width direction of the core. A rectangular cell according to claim 11, characterized in that