Battery cells and battery modules

Abstract

This utility model relates to the field of energy storage equipment technology, and more particularly to a battery cell and battery module. The battery cell includes a core body, which includes a first electrode, a second electrode, and a separator. The first electrode has M groups of first notches spaced sequentially along its length on at least one side. The first segment of the first electrode is further away from the outermost layer of the core body than the second segment. Along the direction from the first segment to the second segment, the area of ​​the first notches in the same group is the same, while the area of ​​the first notches in adjacent groups increases. All first notches are located at the corners of the core body. The second electrode has N groups of second notches spaced sequentially along its length on at least one side in its width direction. The third segment of the second electrode is further away from the outermost layer of the core body than the fourth segment. When the second electrode is unfolded, along the direction from the third segment to the fourth segment, the area of ​​the second notches in the same group is the same, while the area of ​​the second notches in adjacent groups increases. All second notches are located at the corners of the core body.

Description

Technical Field

[0001] This utility model relates to the field of energy storage equipment technology, and in particular to a battery cell and battery module. Background Technology

[0002] A wound battery cell consists of a wound core and an external encapsulation material. For pouch cells, aluminum-plastic film is used as the encapsulation material. The aluminum-plastic film needs to be formed through a stamping process. For a rectangular wound core, the thickness of the aluminum-plastic film is thinnest at the four corners of the stamped core. To ensure the safety of the cell during cycling, a sufficiently large gap needs to be left between the wound core and the aluminum-plastic film to prevent the film from being crushed by the wound core during cycling. Leaving this space will result in a loss of volumetric energy density in the cell. During cell cycling, the corners are the most likely places for the aluminum-plastic film to break. Furthermore, when the cell falls, if the corners hit the ground first, the instantaneous stress at the corners is extremely high, which may cause the aluminum-plastic film to break, electrolyte leakage, or electrode misalignment, increasing the safety risk. Utility Model Content

[0003] One objective of this invention is to provide a battery cell that can help improve the volumetric energy density of the battery cell and help reduce safety risks.

[0004] To achieve this objective, the present invention adopts the following technical solution:

[0005] A battery cell is provided, comprising a core body, the core body including a first electrode, a second electrode, and a separator. At least one side of the first electrode has M groups of first notches in its width direction. The M groups of first notches are sequentially spaced along the length direction of the first electrode. Each group of first notches includes two first notches spaced along the length direction of the first electrode. The first electrode includes a first segment and a second segment sequentially arranged along its own length direction. The first segment is further away from the outermost layer of the core body than the second segment. When the first electrode is unfolded, the area of ​​the first notches in the same group is the same along the direction from the first segment to the second segment, while the area of ​​the first notches in adjacent groups increases. All first notches are located at the corners of the core body. M is a positive integer.

[0006] The second electrode has N sets of second notches on at least one side in the width direction. The N sets of second notches are arranged at intervals along the length direction of the second electrode. Each set of second notches includes two second notches arranged at intervals along the length direction of the second electrode. The second electrode includes a third segment and a fourth segment arranged at intervals along its own length direction. The third segment is further away from the outermost layer of the core than the fourth segment. When the second electrode is unfolded, the area of ​​the second notches in the same group is the same along the direction from the third segment to the fourth segment. The area of ​​the second notches in adjacent groups increases. The second notches are all located at the corners of the core. N is a positive integer.

[0007] Optionally, when the first electrode is unfolded, the depth of the first notch is a1 along the width direction of the first electrode, and the depth a1 of the first notch in the same group is the same along the direction from the first segment to the second segment, while the depth a1 of the first notch in adjacent groups increases.

[0008] When the second electrode is unfolded, the depth of the second notch is b1 along the width direction of the second electrode. Along the direction from the third segment to the fourth segment, the depth b1 of the second notch in the same group is the same, and the depth b1 of the second notch in adjacent groups increases.

[0009] Optionally, the difference in depth a1 between the first gaps in adjacent groups ranges from 0.2 mm to 3 mm;

[0010] The difference in depth b1 between the second gaps in adjacent groups ranges from 0.2 mm to 3 mm.

[0011] Optionally, when the first electrode is unfolded, the maximum width of the first notch is a2 along the length direction of the first electrode, and the maximum width a2 of the first notch in the same group is the same along the direction from the first segment to the second segment, while the maximum width a2 of the first notch in adjacent groups increases.

[0012] When the second electrode is unfolded, along the length of the second electrode, the maximum width of the second notch is b2. Along the direction from the third segment to the fourth segment, the maximum width b2 of the second notch in the same group is the same, and the maximum width b2 of the second notch in adjacent groups increases.

[0013] Optionally, the difference in the maximum width a2 of the first gap in adjacent groups ranges from 0.2mm to 5mm;

[0014] The difference in the maximum width b2 of the second gap in adjacent groups ranges from 0.2mm to 5mm.

[0015] Optionally, in the wound state, the outermost layer of the first electrode sheet is provided with a third notch and a fourth notch on at least one side along the width direction of the first electrode sheet. The third notch and the fourth notch are both located at the corner of the core body. When the first electrode sheet is unwound, the area of ​​the third notch is larger than the area of ​​any one of the first notches. The fourth notch is located at the end of the first electrode sheet along the length direction.

[0016] In the wound state, the outermost layer of the second electrode sheet has a fifth notch and a sixth notch on at least one side along the width direction of the second electrode sheet. The fifth notch and the sixth notch are both located at the corner of the core body. When the second electrode sheet is unwound, the area of ​​the fifth notch is larger than the area of ​​any one of the second notches. The sixth notch is located at the end of the second electrode sheet along the length direction.

[0017] Optionally, when the first electrode is unfolded, along the width direction of the first electrode, the depth of the third notch is the same as the depth of the fourth notch, and the depth of the third notch is greater than the depth of any one of the first notches; when the second electrode is unfolded, along the width direction of the second electrode, the depth of the fifth notch is the same as the depth of the sixth notch, and the depth of the fifth notch is greater than the depth of any one of the second notches.

[0018] And / or, when the first electrode is unfolded, the maximum width of the third notch along the length direction of the first electrode is greater than the maximum width of any one of the first notches; when the second electrode is unfolded, the maximum width of the fifth notch along the length direction of the second electrode is greater than the maximum width of any one of the second notches.

[0019] Optionally, the first electrode is a positive electrode and the second electrode is a negative electrode. The difference between the maximum width a2 of the first notch and the maximum width b2 of the second notch located at the same corner of the core body is in the range of 0.5mm-5mm.

[0020] The difference between the depth a1 of the first notch and the depth b1 of the second notch located at the same corner of the core body ranges from 0.2mm to 2mm.

[0021] Optionally, it also includes an aluminum-plastic film, which covers the outside of the core.

[0022] Another objective of this invention is to provide a battery module that can help improve the volumetric energy density of the battery cell and help reduce safety risks.

[0023] To achieve this objective, the present invention adopts the following technical solution:

[0024] A battery module is provided, comprising at least one of the aforementioned battery cells.

[0025] The beneficial effects of this utility model are:

[0026] This utility model provides a battery cell, including a core body. The core body includes a first electrode, a second electrode, and a separator. At least one side of the first electrode in the width direction is provided with M groups of first notches. The M groups of first notches are arranged at intervals along the length direction of the first electrode. Each group of first notches includes two first notches arranged at intervals along the length direction of the first electrode. The first electrode includes a first segment and a second segment arranged at intervals along its own length direction. The first segment is further away from the outermost layer of the core body than the second segment. When the first electrode is unfolded, the area of ​​the first notches in the same group is the same along the direction from the first segment to the second segment. The area of ​​the first notches in adjacent groups increases. The first notches are all located at the corners of the core body. M is a positive integer. The second electrode sheet has N sets of second notches on at least one side along its width direction. These N sets of second notches are spaced apart sequentially along the length of the second electrode sheet. Each set includes two second notches spaced apart along the length of the second electrode sheet. The second electrode sheet includes a third segment and a fourth segment arranged sequentially along its length. The third segment is further away from the outermost layer of the core than the fourth segment. When the second electrode sheet is unfolded, the area of ​​the second notches in the same group is the same, while the area of ​​the second notches in adjacent groups increases. All second notches are located at the corners of the core, and N is a positive integer. By creating a first notch on the first electrode sheet and a second notch on the second electrode sheet, a recess can be formed at the corner of the core. This prevents a reduction in the thickness of the aluminum-plastic film during stamping and reduces pressure on the aluminum-plastic film at the corners during subsequent use, preventing the film from cracking. Furthermore, since the areas of the outermost first and second notches are larger, sharp edges at the recesses can be avoided to some extent, further reducing the possibility of the aluminum-plastic film cracking due to pressure at the corners of the core. Based on this, the reserved space between the core and the aluminum-plastic film can be reduced, thereby increasing the volumetric energy density of the battery cell. Furthermore, since the diaphragm volume ratio at the corners of the core is large, the diaphragm can also provide buffering when the corners are subjected to stress impact, preventing problems such as aluminum-plastic film rupture, electrolyte leakage, and electrode misalignment, thus reducing safety risks under extreme conditions.

[0027] This invention also provides a battery module including at least one of the aforementioned battery cells. This battery module helps to improve the volumetric energy density of the battery cells and helps to reduce safety risks. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the core structure provided in Embodiment 1 of this utility model;

[0029] Figure 2This is a schematic diagram of the structure of the first electrode provided in Embodiment 1 of this utility model;

[0030] Figure 3 This is a partially enlarged schematic diagram of the first electrode plate provided in Embodiment 1 of this utility model;

[0031] Figure 4 This is a partially enlarged schematic diagram of the second electrode plate provided in Embodiment 1 of this utility model;

[0032] Figure 5 This is a schematic diagram of the battery cell structure provided in Embodiment 1 of this utility model;

[0033] Figure 6 This is a schematic diagram of the core structure provided in Embodiment 2 of this utility model.

[0034] In the picture:

[0035] 1. Core body; 11. First electrode sheet; 111. First notch; 112. Third notch; 113. Fourth notch; 101. Recess;

[0036] 12. Second electrode; 121. Second notch; 122. Fifth notch; 123. Sixth notch;

[0037] 2. Aluminum-plastic film. Detailed Implementation

[0038] The technical solution of this utility model will be further described below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely for explaining this utility model and not for limiting it. Furthermore, it should be noted that, for ease of description, only the parts related to this utility model are shown in the drawings, not all of them.

[0039] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections or detachable connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal connections between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0040] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0041] Example 1

[0042] A wound battery cell consists of a wound core and an external encapsulation material. For pouch cells, aluminum-plastic film is used as the encapsulation material. The aluminum-plastic film needs to be formed through a stamping process. For a rectangular wound core, the thickness of the aluminum-plastic film is thinnest at the four corners of the stamped core. To ensure the safety of the cell during cycling, a sufficiently large gap needs to be left between the wound core and the aluminum-plastic film to prevent the film from being crushed by the wound core during cycling. Leaving this space will result in a loss of volumetric energy density in the cell. During cell cycling, the corners are the most likely places for the aluminum-plastic film to break. Furthermore, when the cell falls, if the corners hit the ground first, the instantaneous stress at the corners is extremely high, which may cause the aluminum-plastic film to break, electrolyte leakage, or electrode misalignment, increasing the safety risk.

[0043] Therefore, this embodiment provides a battery cell to solve the above problems. This battery cell can help improve the volumetric energy density of the battery cell and help reduce safety risks.

[0044] like Figures 1-5 As shown, the battery cell in this embodiment includes a core body 1, which includes a first electrode 11, a second electrode 12, and a separator.

[0045] like Figure 2 and Figure 3 As shown, at least one side of the first electrode 11 in the width direction is provided with M groups of first notches 111. The M groups of first notches 111 are arranged at intervals along the length direction of the first electrode 11. Each group of first notches 111 includes two first notches 111 arranged at intervals along the length direction of the first electrode 11. The first electrode 11 includes a first segment and a second segment arranged at intervals along its own length direction. The first segment is further away from the outermost layer of the core 1 than the second segment. When the first electrode 11 is unfolded, the area of ​​the first notches 111 in the same group is the same along the direction from the first segment to the second segment. The area of ​​the first notches 111 in adjacent groups increases. The first notches 111 are all located at the corner of the core 1. M is a positive integer.

[0046] like Figure 4 As shown, at least one side of the second electrode 12 in the width direction is provided with N sets of second notches 121. The N sets of second notches 121 are arranged at intervals along the length direction of the second electrode 12. Each set of second notches 121 includes two second notches 121 arranged at intervals along the length direction of the second electrode 12. The second electrode 12 includes a third segment and a fourth segment arranged at intervals along its own length direction. The third segment is further away from the outermost layer of the core 1 than the fourth segment. When the second electrode 12 is unfolded, the area of ​​the second notches 121 in the same set is the same along the direction from the third segment to the fourth segment. The area of ​​the second notches 121 in adjacent sets increases. The second notches 121 are all located at the corners of the core 1. N is a positive integer.

[0047] By creating a first notch 111 on the first electrode 11 and a second notch 121 on the second electrode 12, a recess 101 can be formed at the corner of the core body 1, such as... Figure 1 As shown, this design avoids reducing the thickness of the aluminum-plastic film 2 during the stamping process. In subsequent use, it also reduces the pressure exerted on the aluminum-plastic film 2 by the corners of the core body 1, preventing its breakage. Furthermore, since the area of ​​the outermost first notch 111 and the outermost second notch 121 is larger, sharp edges at the recess 101 can be avoided to some extent, further reducing the possibility of the aluminum-plastic film 2 breaking due to pressure from the corners of the core body 1. Based on this, the reserved space between the core body 1 and the aluminum-plastic film 2 can be reduced, increasing the volumetric energy density of the battery cell. Moreover, since the separator does not have notches, the separator volume ratio at the corners of the core body 1 is large. When the corners are subjected to stress impact, the separator can also provide cushioning, preventing problems such as aluminum-plastic film 2 breakage, electrolyte leakage, and electrode misalignment, reducing safety risks in extreme situations.

[0048] It should be noted that the core 1 has a rectangular structure, which is actually a cuboid structure, but because its thickness is relatively small compared to its length and width, it can be approximated as a rectangular structure. The corners of the core 1 mentioned above refer to at least one of the four corners of the rectangular structure. Therefore, the two ends of the opening of a first notch 111 are located on both sides of the thickness direction of the core 1, the two first notches 111 of each group of the first pole pieces 11 are located on the same layer, the two ends of the opening of a second notch 121 are located on both sides of the thickness direction of the core 1, and the two second notches 121 of each group of the second pole pieces 12 are located on the same layer.

[0049] Optionally, in this embodiment, the first electrode 11 is a positive electrode and the second electrode 12 is a negative electrode. Optionally, the value of M ranges from 2 to 7. Optionally, in this embodiment, the value of M is 2, that is, two sets of first notches 111 are formed on the positive electrode, the two first notches 111 in each set have the same area, and the two first notches 111 in each set are located on the same layer. The two first notches 111 located in the inner layer have smaller areas, and the two first notches 111 located in the outer layer have larger areas.

[0050] Optionally, the value of N ranges from 2 to 7. Optionally, in this embodiment, the value of N is also 2, that is, two sets of second notches 121 are formed on the negative electrode, the two second notches 121 in each set have the same area, and the two second notches 121 in each set are located on the same layer. The two second notches 121 located in the inner layer have smaller areas, and the two second notches 121 located in the outer layer have larger areas.

[0051] Optionally, during the winding of the core 1, the first notch 111 and the second notch 121 are set in a one-to-one correspondence.

[0052] Optionally, in the wound state, the outermost layer of the first electrode 11 has a third notch 112 and a fourth notch 113 on at least one side along the width direction of the first electrode 11, and both the third notch 112 and the fourth notch 113 are located at the corners of the core 1. When the first electrode 11 is unwound, the area of ​​the third notch 112 is larger than the area of ​​any one of the first notches 111, and the fourth notch 113 is located at the end of the first electrode 11 along its length direction. The third notch 112 is corresponding to a portion of the first notches 111, and the fourth notch 113 is corresponding to a portion of the first notches 111.

[0053] Optionally, in the wound state, the outermost layer of the second electrode 12 has a fifth notch 122 and a sixth notch 123 on at least one side along the width direction of the second electrode 12, and both the fifth notch 122 and the sixth notch 123 are located at the corners of the core 1. When the second electrode 12 is unwound, the area of ​​the fifth notch 122 is larger than the area of ​​any one of the second notches 121, and the sixth notch 123 is located at the end of the second electrode 12 along the length direction. The fifth notch 122 is corresponding to a portion of the second notches 121, and the sixth notch 123 is corresponding to a portion of the second notches 121.

[0054] Optionally, the third gap 112 is set to correspond with the fifth gap 122, and the fourth gap 113 is set to correspond with the sixth gap 123.

[0055] like Figure 3As shown, optionally, when the first electrode 11 is unfolded, the depth of the first notch 111 along the width direction of the first electrode 11 is a1. Along the direction from the first segment to the second segment, the depth a1 of the first notch 111 in the same group is the same, while the depth a1 of the first notch 111 in adjacent groups increases. Optionally, the difference in depth a1 between adjacent groups of first notches 111 ranges from 0.2mm to 3mm. If this difference is too small, a slope cannot be formed at the recess 101; if this difference is too large, the missing area of ​​the first electrode 11 will be too large after forming a smooth recess 101, which is not conducive to ensuring the capacity of the electrode group.

[0056] like Figure 4 As shown, optionally, when the second electrode 12 is unfolded, the depth of the second notch 121 along the width direction of the second electrode 12 is b1. Along the direction from the third segment to the fourth segment, the depth b1 of the second notches 121 in the same group is the same, while the depth b1 of the second notches 121 in adjacent groups increases. Optionally, the difference in depth b1 between adjacent groups of second notches 121 ranges from 0.2mm to 3mm. If this difference is too small, a slope cannot be formed at the recess 101; if this difference is too large, the missing area of ​​the second electrode 12 will be too large after forming a smooth recess 101, which is not conducive to ensuring the capacity of the electrode group.

[0057] Optionally, in this embodiment, when the first electrode 11 is unfolded, the maximum width of the first notch 111 along the length direction of the first electrode 11 is a2. Along the direction from the first segment to the second segment, the maximum width a2 of the first notches 111 in the same group is the same, while the maximum width a2 of the first notches 111 in adjacent groups increases. Optionally, the difference in the maximum width a2 of the first notches 111 in adjacent groups ranges from 0.2mm to 5mm. If this difference is too small, a slope cannot be formed at the recess 101; if this difference is too large, the missing area of ​​the first electrode 11 will be too large after forming a smooth recess 101, which is not conducive to ensuring the capacity of the electrode group.

[0058] Optionally, in this embodiment, when the second electrode 12 is unfolded, the maximum width of the second notch 121 along the length direction of the second electrode 12 is b2. Along the direction from the third segment to the fourth segment, the maximum width b2 of the second notches 121 in the same group is the same, while the maximum width b2 of the second notches 121 in adjacent groups increases. Optionally, the difference in the maximum width b2 of the second notches 121 in adjacent groups ranges from 0.2mm to 5mm. If this difference is too small, a slope cannot be formed at the recess 101; if this difference is too large, the missing area of ​​the second electrode 12 will be too large after forming a smooth recess 101, which is not conducive to ensuring the capacity of the electrode group.

[0059] Optionally, when the first electrode 11 is unfolded, along the width direction of the first electrode 11, the depth of the third notch 112 is the same as the depth of the fourth notch 113, and the depth of the third notch 112 is greater than the depth of any of the first notches 111. That is, the innermost first notch 111 has the smallest depth, and the outermost first notch 111 has a larger depth, with the third notch 112 having a greater depth than the outermost first notch 111. The difference between the depth c1 of the third notch 112 and the depth a1 of the first notch 111 with the largest depth ranges from 0.2mm to 3mm.

[0060] Optionally, when the second electrode 12 is unfolded, along the width direction of the second electrode 12, the depth of the fifth notch 122 is the same as the depth of the sixth notch 123, and the depth of the fifth notch 122 is greater than the depth of any of the second notches 121. That is, the innermost second notch 121 has the smallest depth, and the outermost second notches 121 have a larger depth, with the fifth notch 122 having a greater depth than the outermost second notch 121. The difference between the depth d1 of the fifth notch 122 and the depth b1 of the second notch 121 with the largest depth ranges from 0.2mm to 3mm.

[0061] Optionally, when the first electrode 11 is unfolded, along the length direction of the first electrode 11, the maximum width of the third notch 112 is greater than the maximum width of any one of the first notches 111. That is, the maximum width of the innermost first notch 111 is the smallest, and the maximum width of the outermost first notch 111 is larger. The maximum width of the third notch 112 is larger than the maximum width of the outermost first notch 111. The difference between the maximum width c2 of the third notch 112 and the maximum width a2 of the first notch 111 with the largest maximum width ranges from 0.2mm to 5mm.

[0062] Optionally, when the second electrode 12 is unfolded, along the length of the second electrode 12, the maximum width of the fifth notch 122 is greater than the maximum width of any second notch 121. That is, the maximum width of the innermost second notch 121 is the smallest, and the maximum width of the outermost second notch 121 is larger. The maximum width of the fifth notch 122 is greater than the maximum width of the outermost second notch 121. The difference between the maximum width d2 of the fifth notch 122 and the maximum width b2 of the second notch 121 with the largest maximum width ranges from 0.2mm to 5mm.

[0063] Optionally, the first electrode 11 is a positive electrode, and the second electrode 12 is a negative electrode. The difference between the maximum width a2 of the first notch 111 and the maximum width b2 of the second notch 121 located at the same corner of the core body 1 ranges from 0.5mm to 5mm. Optionally, the difference between the maximum width c2 of the third notch 112 and the maximum width d2 of the fifth notch 122 located at the same corner of the core body 1 ranges from 0.5mm to 5mm.

[0064] Optionally, the difference between the depth a1 of the first notch 111 and the depth b1 of the second notch 121 located at the same corner of the core body 1 ranges from 0.2mm to 2mm. Optionally, the difference between the depth c1 of the third notch 112 and the depth d1 of the fifth notch 122 located at the same corner of the core body 1 ranges from 0.5mm to 5mm.

[0065] Optionally, M sets of first notches 111 are formed on both sides of the first electrode 11 in the width direction, and the first notches 111 on both sides of the first electrode 11 in the width direction are arranged in a one-to-one correspondence. Optionally, a third notch 112 is formed on both sides of the first electrode 11 in the width direction, and the two third notches 112 on both sides of the first electrode 11 in the width direction are arranged in a corresponding manner. A fourth notch 113 is formed on both sides of the end of the first electrode 11 along the width direction of the first electrode 11.

[0066] Optionally, N sets of second notches 121 are formed on both sides of the second electrode 12 in the width direction, and the second notches 121 on both sides of the second electrode 12 in the width direction are arranged in a one-to-one correspondence. Optionally, a fifth notch 122 is formed on both sides of the second electrode 12 in the width direction, and the two fifth notches 122 on both sides of the second electrode 12 in the width direction are arranged in a corresponding manner. A sixth notch 123 is formed on both sides of the end of the second electrode 12 along the width direction of the second electrode 12.

[0067] Optionally, when the first electrode 11 is unfolded, the first electrode 11 on both sides of the opening of the first notch 111 is rounded. Optionally, when the first electrode 11 is unfolded, the first electrode 11 on both sides of the opening of the third notch 112 is rounded. Optionally, when the first electrode 11 is unfolded, the first electrode 11 on one side of the opening of the fourth notch 113 is rounded.

[0068] Optionally, when the second electrode 12 is unfolded, the second electrode 12 on both sides of the opening of the second notch 121 is rounded. Optionally, when the second electrode 12 is unfolded, the second electrode 12 on both sides of the opening of the fifth notch 122 is rounded. Optionally, when the second electrode 12 is unfolded, the second electrode 12 on one side of the opening of the sixth notch 123 is rounded.

[0069] Optionally, when the first electrode 11 is unfolded, the first notch 111 is a first rectangular structure, and the corners of the first rectangular structure away from the opening of the first notch 111 are all rounded. Optionally, when the first electrode 11 is unfolded, the third notch 112 is also a first rectangular structure, and the corners of the first rectangular structure away from the opening of the third notch 112 are all rounded.

[0070] Optionally, when the second electrode 12 is unfolded, the second notch 121 is a second rectangular structure, and the corners of the opening of the second rectangular structure away from the second notch 121 are all rounded. Optionally, when the second electrode 12 is unfolded, the fifth notch 122 is also a second rectangular structure, and the corners of the opening of the second rectangular structure away from the fifth notch 122 are all rounded.

[0071] It is known that the above-mentioned rounded treatments are all conducive to ensuring that no sharp edges or corners appear at the recess 101, which can further prevent the aluminum-plastic film 2 from being punctured.

[0072] like Figure 5 As shown, optionally, the battery cell also includes an aluminum-plastic film 2, which covers the outside of the core body 1. In the prior art, the aluminum-plastic film needs to cover the corners of the core body with sharp edges, resulting in a reduction in film thickness at these locations, making it prone to breakage. However, in this embodiment, the core body 1 has a recess 101 at the corners, significantly reducing the thickness reduction of the aluminum-plastic film 2 at these corners, thus helping to prevent the aluminum-plastic film 2 from breaking.

[0073] Optionally, the aluminum-plastic film 2 is shaped, that is, after the aluminum-plastic film 2 is punched, the material at the corners is pressed into the corner recess 101, and the original protrusion at the bottom of the aluminum-plastic film 2 is reduced, thereby achieving the purpose of reducing the height of the battery cell.

[0074] Example 2

[0075] like Figure 6 As shown, this embodiment discloses a battery cell. The difference between the battery cell in this embodiment and the battery cell in Embodiment 1 is that the maximum width of the plurality of first notches 111 of the first electrode 11 of the battery cell in this embodiment is the same, and the maximum width of the first notch 111 is also the same as the maximum width of the third notch 112. Furthermore, the maximum width of the plurality of second notches 121 of the second electrode 12 of the battery cell is the same, and the maximum width of the second notch 121 is also the same as the maximum width of the fifth notch 122.

[0076] To verify whether this battery cell has higher safety compared to existing battery cells, this embodiment provides experimental data as shown in Table 1 below, including two experimental groups and three control groups. In the two experimental groups, the positive and negative electrodes of the battery cells were cut with notches to create a recess 101 at the corner of the cell. In the three control groups, the positive and negative electrodes of the battery cells were not cut with notches, and the corners of the battery cells did not have the recess 101.

[0077] Table 1

[0078]

[0079] Table 2

[0080]

[0081] As shown in Table 2 above, the experimental results indicate that, with similar corner breakage rates, the cell with the corner recess 101 exhibits a significant increase in capacity. Furthermore, with similar cell capacities, the cell with the corner recess 101 exhibits a significantly reduced corner breakage rate. Additionally, even with a thinner aluminum-plastic film, the corner breakage rate remains zero due to the corner recess 101 on the core body 1. Moreover, the corner shaping of the aluminum-plastic film can reduce the cell thickness and increase its volumetric energy density. Therefore, by cutting the first notch 111, the third notch 112, and the fourth notch 113 on the positive electrode, and the second notch 121, the fifth notch 122, and the sixth notch 123 on the negative electrode, forming the corner recess 101 on the core body 1 helps to improve the volumetric energy density of the cell and reduces safety risks.

[0082] Apart from the above, the rest of the structure of the battery cell provided in this embodiment is the same as that of the battery cell in Embodiment 1, and will not be described again here.

[0083] Example 3

[0084] This embodiment provides a battery module, including at least one battery cell from either Embodiment 1 or Embodiment 2. This battery module can help improve the volumetric energy density of the battery cell and help reduce safety risks.

[0085] Obviously, the above embodiments of this utility model are merely examples for clearly illustrating the present utility model, and are not intended to limit the implementation of the present utility model. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the protection scope of the claims of this utility model.

Claims

1. An electric cell, characterized by, The core (1) includes a first electrode (11), a second electrode (12), and a diaphragm. At least one side of the first electrode (11) in the width direction is provided with M sets of first notches (111). The M sets of first notches (111) are arranged sequentially and spaced apart along the length direction of the first electrode (11). Each set of first notches (111) includes two first notches (111) arranged spaced apart along the length direction of the first electrode (11). The first electrode (11) includes a first segment and a second segment arranged sequentially along its own length direction. The first segment is further away from the outermost layer of the core (1) than the second segment. When the first electrode (11) is unfolded, the area of ​​the first notches (111) in the same group is the same along the direction from the first segment to the second segment. The area of ​​the first notches (111) in adjacent groups increases. The first notches (111) are all located at the corner of the core (1). M is a positive integer. The second pole piece (12) has N sets of second notches (121) at least one side in the width direction. The N sets of second notches (121) are arranged at intervals along the length direction of the second pole piece (12). Each set of second notches (121) includes two second notches (121) arranged at intervals along the length direction of the second pole piece (12). The second pole piece (12) includes a third segment and a fourth segment arranged at intervals along its own length direction. The third segment is further away from the outermost layer of the core body (1) than the fourth segment. When the second pole piece (12) is unfolded, the area of ​​the second notches (121) in the same group is the same along the direction from the third segment to the fourth segment. The area of ​​the second notches (121) in adjacent groups increases. The second notches (121) are all located at the corner of the core body (1). N is a positive integer.

2. The battery cell according to claim 1, characterized in that, When the first electrode (11) is unfolded, the depth of the first notch (111) is a1 along the width direction of the first electrode (11). Along the direction from the first segment to the second segment, the depth a1 of the first notch (111) in the same group is the same, and the depth a1 of the first notch (111) in adjacent groups increases. When the second electrode (12) is unfolded, the depth of the second notch (121) is b1 along the width direction of the second electrode (12). Along the direction from the third segment to the fourth segment, the depth b1 of the second notch (121) in the same group is the same, and the depth b1 of the second notch (121) in adjacent groups increases.

3. The battery cell according to claim 2, characterized in that, The difference in depth a1 between the first gaps (111) of adjacent groups ranges from 0.2 mm to 3 mm. The difference in depth b1 between the second gaps (121) of adjacent groups ranges from 0.2 mm to 3 mm.

4. The battery cell according to claim 2, characterized in that, When the first electrode (11) is unfolded, along the length direction of the first electrode (11), the maximum width of the first notch (111) is a2. Along the direction from the first segment to the second segment, the maximum width a2 of the first notch (111) in the same group is the same, and the maximum width a2 of the first notch (111) in adjacent groups increases. When the second electrode (12) is unfolded, along the length direction of the second electrode (12), the maximum width of the second notch (121) is b2. Along the direction from the third segment to the fourth segment, the maximum width b2 of the second notch (121) in the same group is the same, and the maximum width b2 of the second notch (121) in adjacent groups increases.

5. The battery cell according to claim 4, characterized in that, The difference in the maximum width a2 of the first gap (111) in adjacent groups ranges from 0.2mm to 5mm; The difference in the maximum width b2 of the second gap (121) of the adjacent group ranges from 0.2mm to 5mm.

6. The battery cell according to claim 2, characterized in that, In the wound state, the outermost layer of the first electrode (11) is provided with a third notch (112) and a fourth notch (113) on at least one side along the width direction of the first electrode (11). The third notch (112) and the fourth notch (113) are both located at the corner of the core (1). When the first electrode (11) is unfolded, the area of ​​the third notch (112) is larger than the area of ​​any one of the first notches (111). The fourth notch (113) is located at the end of the first electrode (11) along the length direction. In the wound state, the outermost layer of the second electrode (12) is provided with a fifth notch (122) and a sixth notch (123) on at least one side along the width direction of the second electrode (12). The fifth notch (122) and the sixth notch (123) are both located at the corner of the core (1). When the second electrode (12) is unfolded, the area of ​​the fifth notch (122) is larger than the area of ​​any one of the second notches (121). The sixth notch (123) is located at the end of the second electrode (12) along the length direction.

7. The battery cell according to claim 6, characterized in that, When the first electrode (11) is unfolded, along the width direction of the first electrode (11), the depth of the third notch (112) is the same as the depth of the fourth notch (113), and the depth of the third notch (112) is greater than the depth of any one of the first notches (111). When the second electrode (12) is unfolded, along the width direction of the second electrode (12), the depth of the fifth notch (122) is the same as the depth of the sixth notch (123), and the depth of the fifth notch (122) is greater than the depth of any one of the second notches (121). And / or, when the first electrode (11) is unfolded, along the length direction of the first electrode (11), the maximum width of the third notch (112) is greater than the maximum width of any one of the first notches (111), and when the second electrode (12) is unfolded, along the length direction of the second electrode (12), the maximum width of the fifth notch (122) is greater than the maximum width of any one of the second notches (121).

8. The battery cell according to claim 4, characterized in that, The first electrode (11) is a positive electrode, and the second electrode (12) is a negative electrode. The difference between the maximum width a2 of the first notch (111) and the maximum width b2 of the second notch (121) located at the same corner of the core body (1) is 0.5mm-5mm. The difference between the depth a1 of the first notch (111) and the depth b1 of the second notch (121) located at the same corner of the core (1) is in the range of 0.2mm-2mm.

9. The battery cell according to any one of claims 1-6, characterized in that, It also includes an aluminum-plastic film (2), which covers the outside of the core (1).

10. A battery module, characterized in that, It includes at least one battery cell as described in any one of claims 1-9.

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