Battery and electric device

Abstract

The utility model discloses a kind of battery and electrical equipment, battery includes: bare cell, bare cell includes main body part and thinning portion, thinning portion is connected at the end of main body part;Encapsulation film, encapsulation film includes the metal layer and insulating layer that are sequentially laminated, encapsulation film is equipped with the storage cavity of accommodating bare cell, the cavity wall of storage cavity is equipped with the groove of at least one side in the thickness direction of bare cell, groove includes at least part by the bottom wall of metal layer is formed, and by the transition side wall of insulating layer is formed, transition side wall surrounds the circumferential edge connected to bottom wall, transition side wall has the first edge away from bottom wall and the second edge close to bottom wall;Along the thickness direction of bare cell, at least part of the projection of protruding portion falls in the projection range of transition side wall, the projection of main body part falls in the projection range of bottom wall.The battery of the utility model can have higher charging window and safety reliability.

Description

Technical Field

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

[0002] In related technologies, the battery comprises an aluminum-plastic film and a bare cell. After the aluminum-plastic film is perforated, it has a storage cavity in which the bare cell can be placed. To improve the volumetric energy density of the battery, the PP inner layer of the aluminum-plastic film can be removed to form a groove on the cavity wall to accommodate the bare cell. However, to ensure the energy density gain of the battery, the depth of the groove is generally close to the thickness of the PP layer of the aluminum-plastic film, thus exposing the aluminum layer of the aluminum-plastic film. At this point, only a separator separates the negative electrode and the aluminum layer of the aluminum-plastic film at the end of the bare cell. When mechanical vibration or thermal shrinkage occurs, it is easy for the negative electrode to contact the aluminum layer of the aluminum-plastic film and short-circuit, greatly reducing the safety and reliability of the battery. In addition, existing soft-pack lithium-ion batteries have a low charging window and poor charging performance, making it difficult to meet the requirements of high-rate fast charging. Utility Model Content

[0003] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes a battery that possesses high safety and reliability as well as a wide charging window.

[0004] This utility model also proposes an electrical device.

[0005] The battery according to a first aspect embodiment of the present invention includes:

[0006] A bare battery cell includes a main body and a thinned portion with a thickness less than that of the main body. The thinned portion is connected to the end of the main body. The negative electrode of the bare battery cell has a protruding portion located inside the thinned portion. Along the thickness direction of the bare battery cell, the projection of the protruding portion does not overlap with the projection of the positive electrode of the bare battery cell.

[0007] An encapsulation film includes a metal layer and an insulating layer stacked sequentially. The encapsulation film has a storage cavity for accommodating the bare battery cell. The cavity wall has a groove on at least one side in the thickness direction of the bare battery cell. The groove includes a bottom wall formed at least partially by the metal layer and a transition sidewall formed by the insulating layer. The transition sidewall surrounds a circumferential edge connected to the bottom wall and has a first edge away from the bottom wall and a second edge close to the bottom wall. The first edge and the second edge are offset in the thickness direction of the bare battery cell.

[0008] Along the thickness direction of the bare cell, at least a portion of the projection of the protrusion falls within the projection range of the transition sidewall, and the projection of the main body falls within the projection range of the bottom wall.

[0009] The battery according to the embodiments of this utility model has at least the following beneficial effects: the groove wall includes a transition sidewall, the bare cell includes a thinned portion, the bare cell is disposed in the groove, the thinned portion corresponds to the transition sidewall, the protruding portion of the negative electrode is located in the thinned portion, and the protruding portion of the negative electrode can overlap the transition sidewall, thereby avoiding contact between the protruding portion of the negative electrode and the metal layer of the encapsulation film, enabling the battery to have higher safety and reliability. At the same time, the thinned portion can effectively improve the charging window of the battery, making its charging performance better.

[0010] According to some embodiments of the present invention, the transition sidewall of the battery is a stepped structure or a ramp structure.

[0011] According to some embodiments of the present invention, the transition sidewall of the battery is a stepped structure, which includes a first wall, a second wall and a third wall. One end of the second wall is connected to the first wall and the other end is connected to the third wall. The second wall forms a stepped surface. The end of the first wall away from the second wall constitutes the first edge, and the end of the third wall away from the second wall constitutes the second edge.

[0012] According to some embodiments of the present invention, in the battery, along the thickness direction of the bare cell, the size of the first wall is H1, the size of the insulating layer is H2, and 0.1H2≤H1≤0.8H2.

[0013] According to some embodiments of the present invention, the horizontal distance between the first wall and the third wall in the battery is 2 to 10 mm.

[0014] According to some embodiments of the present invention, the transition sidewall of the battery has a sloping structure.

[0015] According to some embodiments of the present invention, the horizontal distance between the first edge and the second edge of the battery is 2 to 10 mm.

[0016] According to some embodiments of the present invention, the bare cell is a wound structure, the positive electrode sheet includes a positive current collector and a positive electrode film layer disposed on at least one side surface of the positive current collector, the positive electrode film layer includes a first thinning region and a first main body region, the first thinning region is connected to both ends of the first main body region in the width direction, the first thinning region forms a portion of the thinned portion, and the first main body region forms a portion of the main body portion.

[0017] According to some embodiments of the present invention, the negative electrode sheet includes a negative electrode current collector and a negative electrode film layer disposed on at least one side surface of the negative electrode current collector. The negative electrode film layer includes a second thinning region and a second main body region. The second thinning region is connected to both ends of the second main body region in the width direction. The second thinning region forms a portion of the thinned portion. The second thinning region includes the protruding portion. The second main body region forms a portion of the main body region.

[0018] According to some embodiments of the present invention, the bare cell is a stacked structure, the positive electrode sheet includes a positive current collector and a positive electrode film layer disposed on at least one side surface of the positive current collector, the positive electrode film layer includes a first thinning region and a first main body region, the first thinning region is connected to both ends of the first main body region in the length direction and both ends of the second main body region in the width direction, the first thinning region forms a portion of the thinned portion, and the first main body region forms a portion of the main body portion.

[0019] According to some embodiments of the present invention, the negative electrode sheet includes a negative electrode current collector and a negative electrode film layer disposed on at least one side surface of the negative electrode current collector. The negative electrode film layer includes a second thinning region and a second main body region. The second thinning region is connected to both ends of the second main body region in the length direction and both ends of the second main body region in the width direction. The second thinning region forms a portion of the thinned portion and includes the protruding portion. The second main body region forms a portion of the main body portion.

[0020] According to some embodiments of the present invention, in the battery, along the thickness direction of the bare cell, a portion of the second thinning region is projected onto the transition sidewall, and another portion of the second thinning region is projected onto the first thinning region.

[0021] According to some embodiments of the present invention, in the battery, at least a portion of the projection of the first thinned region falls on the transition sidewall along the thickness direction of the bare cell.

[0022] According to some embodiments of the battery of this utility model, a first region point is defined on the first thinning region. The distance between the first region point and the end of the first thinning region away from the first main body region is D, where D = 5 mm. The thickness of the first thinning region at the first region point is W1, and the thickness of the first main body region is W2, where 0.88W2 < W1 < W2. Preferably, 0.94W2 ≤ W1 < W2.

[0023] 18. In a battery according to some embodiments of the present invention, a second region point is defined on the second thinning region, the distance between the second region point and the end of the second thinning region away from the second main body region is E, E = 5mm, wherein the thickness of the second thinning region located at the second region point is W3, the thickness of the second main body region is W4, and 0.88W4 < W3 < W4. Preferably, 0.94W4 ≤ W3 < W4.

[0024] According to some embodiments of the present invention, the battery further includes at least one of the following (1)-(4):

[0025] (1) The outermost electrode of the bare cell in its thickness direction is the positive electrode;

[0026] (2) The encapsulation film further includes a protective layer, which is disposed on the side of the metal layer away from the insulating layer, and the protective layer includes a nylon layer;

[0027] (3) The metal layer includes an Al layer;

[0028] (4) The insulating layer includes a PP layer.

[0029] The electrical device according to the second aspect of the present invention includes the battery described in any one of the first aspect embodiments.

[0030] The electrical device according to the embodiments of this utility model has at least the following beneficial effects: the groove wall includes a transition sidewall, the bare battery cell includes a thinned portion, the bare battery cell is disposed in the groove, the thinned portion corresponds to the transition sidewall, the protruding portion of the negative electrode sheet is located in the thinned portion, and the protruding portion of the negative electrode sheet can overlap the transition sidewall, thereby avoiding contact between the protruding portion of the negative electrode sheet and the metal layer of the encapsulation film, enabling the battery to have higher safety and reliability. Simultaneously, the thinned portion effectively improves the charging window of the battery, resulting in better charging performance. Furthermore, the electrical device with this battery has higher reliability.

[0031] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0032] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0033] Figure 1 This is a schematic diagram of a battery according to the first embodiment of the present invention;

[0034] Figure 2 This is a schematic diagram of a battery according to the second embodiment of the present invention;

[0035] Figure 3 This is a schematic diagram of a battery according to the third embodiment of the present invention;

[0036] Figure 4 This is a schematic diagram of the battery according to the fourth embodiment of the present invention;

[0037] Figure 5 This is a schematic diagram of the battery according to the fifth embodiment of the present invention;

[0038] Figure 6 This is a schematic diagram of the battery according to the sixth embodiment of the present invention;

[0039] Figure 7 This is a schematic diagram of the positive electrode plate in a battery according to some embodiments of the present invention;

[0040] Figure 8 This is a schematic diagram of the negative electrode sheet in a battery according to some embodiments of the present invention;

[0041] Figure 9 This is a schematic diagram of an encapsulation film in the prior art;

[0042] Figure 10 This is a schematic diagram of the encapsulation film in a battery according to some embodiments of the present invention.

[0043] Figure label:

[0044] Battery 10, encapsulation film 100, storage cavity 110, groove 120, transition sidewall 130, first wall 131, second wall 132, third wall 133, first edge 134, second edge 135, bottom wall 140, bare cell 200, main body 210, thinned part 220, insulating layer 300, metal layer 400, protective layer 500, positive electrode 600, first thinned area 610, first main body area 620, negative electrode 700, second thinned area 710, second main body area 720. Detailed Implementation

[0045] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.

[0046] In the description of this utility model, it should be understood that the directional descriptions, such as up, down, front, back, left, right, etc., indicate the directional or positional relationship based on the directional or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0047] In the description of this utility model, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0048] In the description of this utility model, unless otherwise explicitly defined, terms such as "setting," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this utility model in conjunction with the specific content of the technical solution.

[0049] In the description of this utility model, the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this utility model. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0050] Please refer to Figures 1 to 8 In some embodiments, the battery 10 includes an encapsulation film 100 and a bare cell 200. The encapsulation film 100 includes a protective layer 500, a metal layer 400, and an insulating layer 300 stacked sequentially. The encapsulation film 100 has a storage cavity 110 for accommodating the bare cell. The shape of the storage cavity 110 can correspond to the shape of the bare cell 200. For example, the shape of the storage cavity 110 can be a cube, cuboid, or cylinder, and the shape of the bare cell 200 can also be a cube, cuboid, or cylinder. The encapsulation film 100 can be made of aluminum-plastic film. Correspondingly, its protective layer 500 is a nylon layer, the metal layer 400 is an Al layer, and the insulating layer 300 is a PP layer. The cavity wall of the storage cavity 110 is provided with a groove 120, which can be located on at least one side in the thickness direction of the bare cell 200. Specifically, as shown... Figure 1As shown, one groove 120 can be provided, and the groove 120 is located on either side of the thickness direction of the bare cell 200. Figure 3 As shown, two grooves 120 can also be provided, with the two grooves 120 located on both sides of the bare cell 200 in the thickness direction.

[0051] Furthermore, the groove wall of the groove 120 includes a transition sidewall 130 and a bottom wall 140, the transition sidewall 130 surrounding the circumferential edge connected to the bottom wall 140. The bottom wall 140 is at least partially formed of a metal layer 400, which includes completely removing the insulating layer 300 at the corresponding location of the bottom wall 140, while not excluding the possibility that some insulating layer 300 may not be completely removed. Figure 1-6 As shown, the bottom wall 140 can be a plane, such as... Figure 10 As shown, the bottom wall 140 can also be grooved. For example... Figure 1 As shown, the transition sidewall 130 is formed of an insulating layer 300. The transition sidewall 130 has a first edge 134 away from the bottom wall 140 and a second edge 135 near the bottom wall 140. The first edge 134 and the second edge 135 are offset in the thickness direction of the bare cell 200.

[0052] Furthermore, the bare cell 200 is disposed in the groove 120, and the bare cell 200 can be a wound structure or a stacked structure. The bottom wall 140 is located on at least one side in the thickness direction of the bare cell 200. That is, when there is one groove 120, one bottom wall 140 is located on one side in the thickness direction of the bare cell 200; when there are two grooves 120, the two bottom walls 140 are respectively located on both sides in the thickness direction of the bare cell 200. The bare cell 200 includes a main body portion 210 and a thinned portion 220, and the thinned portion 220 is connected to the end of the main body portion 210. The negative electrode 700 of the bare cell 200 has a protruding portion, and along the thickness direction of the bare cell 200, the projection of the protruding portion does not overlap with the projection of the positive electrode 600 of the bare cell 200, and the protruding portion is located within the thinned portion 220. The bare battery cell 200 includes a main body portion 210 and a thinned portion 220. Specifically, the main body portion 210 is located in the middle of the bare battery cell 200, and the thinned portion 220 is located at the edge of the bare battery cell 200. The thickness of the edge of the bare battery cell 200 is less than the thickness of the middle portion; that is, the thickness of the main body portion 210 is greater than the thickness of the thinned portion 220. The thinned portion 220 specifically refers to thinning the active material layer on the bare battery cell 200. Along the thickness direction of the bare battery cell 200, at least a portion of the projection of the protruding portion falls within the projection range of the transition sidewall 130; that is, the thinned portion 220 at least partially overlaps the transition sidewall 130. The projection of the main body portion 210 falls within the projection range of the bottom wall 140; that is, the main body portion 210 overlaps the bottom wall 140. Specifically, the groove wall of the recess 120 includes a transition sidewall 130, and the bare cell 200 includes a thinned portion 220. The bare cell 200 is disposed in the recess 120, and the thinned portion 220 corresponds to the transition sidewall 130. The protruding portion of the negative electrode 700 is located in the thinned portion 220, and the protruding portion of the negative electrode 700 can overlap the transition sidewall 130. The transition sidewall 130 can effectively prevent the protruding portion of the negative electrode 700 from contacting the metal layer 400, thereby giving the battery 10 higher safety and reliability. In addition, the cooperation between the transition sidewall 130 and the thinned portion 220 can effectively prevent the thickness of this area, thereby improving the volumetric energy density of the battery 10.

[0053] Furthermore, the specific structure of the transition sidewall 130 is described below; please refer to [reference needed]. Figure 1 or Figure 4In some embodiments, the transition sidewall 130 has a stepped or sloping structure. When the transition sidewall 130 has a stepped structure, it includes a first wall 131, a second wall 132, and a third wall 133. The two ends of the second wall 132 are connected to the first wall 131 and the third wall 133, respectively, forming a stepped surface. In this case, the end of the first wall 131 away from the second wall 132 forms a first edge 134, and the end of the third wall 133 away from the second wall 132 forms a second edge 135. One end of the third wall 133 is connected to the bottom wall 140. The bare cell 200 is located in the groove 120. A portion of the thinned portion 220 can overlap the second wall 132, and another portion can overlap the bottom wall 140. By thinning the edge of the bare cell 200 and creating the transition sidewall 130 for the insulating layer 300, the charging window and safety reliability of the battery 10 can be improved. In addition, it should be noted that the combination of the thinned portion 220 and the transition sidewall 130 can also effectively improve the flatness of the battery 10.

[0054] Further, please refer to Figure 1 In some embodiments, along the thickness direction of the bare cell 200, the dimension of the first wall 131 is H1, and the dimension of the insulating layer 300 is H2, where 0.1H2≤H1≤0.8H2. Specifically, 0.1H2≤H1≤0.8H2 can be H1=0.1H2, H1=0.2H2, H1=0.3H2, H1=0.4H2, H1=0.5H2, H1=0.6H2, H1=0.7H2, or H1=0.8H2. Along the thickness direction of the bare cell 200, the dimension of the insulating layer 300 refers to the thickness of the insulating layer 300. When the dimension of the first wall 131 is less than 0.1H2, the dimension of the first wall 131 is too small, which will result in an excessively large total thickness of the thinned portion 220 and the transition sidewall 130, thereby reducing the energy density gain of the battery 10. When the size of the first wall 131 is greater than 0.8H2, the distance between the thinned portion 220 and the metal layer 400 may be too small. This could easily cause the protruding portion of the negative electrode 700 to come into contact with the metal layer 400, resulting in lower safety of the battery 10. When 0.1H2≤H1≤0.8H2, the battery 10 can have both reliable safety and high energy density.

[0055] Further, please refer to Figure 1In some embodiments, the horizontal distance between the first wall 131 and the third wall 132 is A, where 2mm ≤ A ≤ 10mm. A can be 10mm, 9mm, 8mm, 7mm, 6mm, 5mm, 4mm, 3mm, or 2mm. At least a portion of the thinned portion 220 is located on the second wall 132, and the position of the second wall 132 corresponds to the thinned portion 220. If the size of the second wall 132 is too small, the area supporting the thinned portion 220 will be small, and the protruding portion of the negative electrode 700 may still easily contact the metal layer 400. When 2mm ≤ A ≤ 10mm, the transition sidewall 130 has sufficient area to support the thinned portion 220 of the battery 10, ensuring the safety and reliability of the battery 10.

[0056] Please refer to Figures 4 to 6 When the transition sidewall 130 has a sloping structure, in some embodiments, the transition sidewall 130 gradually tapers from the bare cell 200 to the bottom wall 140. The transition sidewall 130 can be a slope or a curved surface. Correspondingly, the thickness of the thinned portion 220 gradually increases from the thinned portion 220 to the main body 210. The cooperation between the transition sidewall 130 and the thinned portion 220 can effectively prevent the battery 10 from having a low energy density. Further, the slope width is A, that is, the horizontal distance between the first edge and the second edge is A, where A = 2~10mm. A can be 10mm, 9mm, 8mm, 7mm, 6mm, 5mm, 4mm, 3mm, or 2mm. Similarly, at least a portion of the thinned portion 220 is located on the slope surface of the transition sidewall 130. If the size of A is too small, the area of ​​the transition sidewall 130 supporting the thinned portion 220 will be small, and the protruding part of the negative electrode 700 may still easily come into contact with the metal layer 400. However, when 2mm≤A≤10mm, the transition sidewall 130 can have a sufficient area to support the thinned portion 220 of the battery 10, ensuring that the protruding part of the negative electrode 700 overlaps with the transition sidewall 130, thereby ensuring the safety and reliability of the battery 10.

[0057] Furthermore, the specific structure of the bare cell 200 is described below. Please refer to [link / reference]. Figure 2 and Figure 5In some embodiments, the bare cell 200 has a wound structure. The positive electrode 600, negative electrode 700, and separator (not shown) are stacked and wound together. The separator is located between the positive electrode 600 and the negative electrode 700. The outermost ring of the bare cell 200 is the positive electrode 600, meaning that after winding, the positive electrode 600 is located on the outermost side in the thickness direction of the bare cell 200. The positive electrode 600 includes a positive current collector and a positive electrode film layer disposed on at least one surface of the positive current collector. The positive electrode film layer includes a first thinning region 610 and a first main body region 620. The first thinning region 610 is connected to both ends of the first main body region 620 in the width direction. The first thinning region 610 forms a portion of the thinned portion 220, and the first main body region 620 forms a portion of the main body portion 210. That is, in this embodiment, the two edges of the positive electrode 600 in the width direction of the wound cell are thinned. Furthermore, in some embodiments, the negative electrode 700 includes a negative current collector and a negative electrode film layer disposed on at least one side surface of the negative current collector. The negative electrode film layer includes a second thinning region 710 and a second main body region 720. The second thinning region 710 is connected to both ends of the second main body region 720 in the width direction. The second thinning region 710 forms a portion of the thinned portion 220 and includes a protruding portion. The second main body region 720 forms a portion of the main body portion 210. That is, in this embodiment, the two sides of the negative electrode 700 of the wound cell in the width direction are thinned.

[0058] When the bare cell 200 has a stacked structure, multiple positive electrode plates 600 and multiple negative electrode plates 700 are alternately stacked, and a separator (not shown in the figure) is provided between the positive electrode plates 600 and the negative electrode plates 700. The separator can adopt the conventional "Z" shaped folding method. The outermost electrode plate of the bare cell 200 in its thickness direction is the positive electrode plate 600. The positive electrode plate 600 includes a positive current collector and a positive electrode film layer disposed on at least one side surface of the positive current collector. The positive electrode film layer includes a first thinning region 610 and a first main body region 620. The first thinning region 610 is connected to both ends in the length direction and both ends in the width direction of the first main body region 620. That is, the four edges of the positive electrode film layer are thinned. The first thinning region 610 forms part of the thinned portion 220, and the first main body region 620 forms part of the main body portion 210. Furthermore, in some embodiments, the negative electrode 700 includes a negative electrode current collector and a negative electrode film layer disposed on at least one side surface of the negative electrode current collector. The negative electrode film layer includes a second thinning region 710 and a second main body region 720. The second thinning region 710 is connected to both ends of the second main body region 720 in the length direction and both ends of the second main body region 720 in the width direction. That is, all four edges of the negative electrode film layer are also thinned. The second thinning region 710 forms part of the thinned portion 220 and includes a protrusion. The second main body region 720 forms part of the main body portion 210.

[0059] Furthermore, in some embodiments, regardless of whether the bare cell 200 has a wound or stacked structure, the edge thinning of the positive electrode 600 and the negative electrode 700 can be gradient thinning to ensure a smooth transition in film thickness. Simultaneously, each structure can be designed as follows: specifically, along the thickness direction of the bare cell 200, a portion of the second thinning region 710 projects onto the transition sidewall 130, and another portion of the second thinning region 710 projects onto the first thinning region 610. Those skilled in the art should understand that, to avoid lithium-ion deposition during charging, the negative electrode 700 is typically designed to be larger than the positive electrode 600. For example, along either side of the electrode width direction, the negative electrode 700 is 0.4-1 mm larger than the positive electrode 600 to ensure that the negative electrode 700 has sufficient space to accommodate the embedded lithium ions. Therefore, the second thinning region 710 protrudes relative to the first thinning region 610. The protruding portion (i.e., the extended portion) of the second thinning region 710 overlaps with the transition sidewall 130, thereby further preventing the negative electrode 700 from contacting the metal layer 400. This effectively avoids the safety problem of short circuit in the battery 10, improves the safety and reliability of the battery 10 and its charging window, and also gives the battery 10 energy density gains. In some embodiments, at least a portion of the projection of the first thinning region 610 along the thickness direction of the bare cell 200 falls on the transition sidewall 130. In this case, it can better prevent the negative electrode 700 from contacting the metal layer 400, resulting in higher safety and reliability of the battery 10 and higher energy density gains.

[0060] Further, please refer to Figure 7 In some embodiments, a first region point is defined on the first thinning region 610, and the distance between the first region point and the end of the first thinning region 610 away from the first main body region 620 is D, where D = 5 mm. The thickness of the first thinning region 610 at the first region point is W1, and the thickness of the first main body region 620 is W2, where 0.88W2 < W1 < W2. Specifically, W1 can be W1 = 0.89W2, W1 = 0.90W2, W1 = 0.91W2, W1 = 0.92W2, W1 = 0.93W2, W1 = 0.94W2, W1 = 0.95W2, W1 = 0.96W2, W1 = 0.97W2, W1 = 0.98W2, or W1 = 0.99W2. When W1 is less than 0.88W2, more active material is removed from the first thinning region 610, which leads to a lower energy density of the battery 10. Preferably, 0.94W2≤W1<W2.

[0061] Further, please refer to Figure 8In some embodiments, a second region point is defined on the second thinning region 710, and the distance between the second region point and the end of the second thinning region 710 away from the second main body region 720 is E, where E = 5 mm. The thickness of the second thinning region 710 located at the second region point is W3, and the thickness of the second main body region 720 is W4, where 0.88W4 < W3 < W4. Specifically, W3 can be W3 = 0.89W4, W3 = 0.90W4, W3 = 0.91W4, W3 = 0.92W4, W3 = 0.93W4, W3 = 0.94W4, W3 = 0.95W4, W3 = 0.96W4, W3 = 0.97W4, W3 = 0.98W4, or W3 = 0.99W4. When W3 is less than 0.88W4, more active material is removed from the second thinning region 710, which leads to a lower energy density of the battery 10. Preferably, 0.94W4≤W3<W4.

[0062] Further, please refer to Figure 1 In some embodiments, the bottom wall 140 includes a stacked metal layer 400 and a protective layer 500. In the prior art, the cavity wall of the storage cavity 110 includes a stacked insulating layer 300, a metal layer 400, and a protective layer 500. After the middle region of the insulating layer 300 is removed by laser, the bottom wall 140 includes the stacked metal layer 400 and the protective layer 500. The method of cutting the insulating layer 300 down to the metal layer 400 allows for a greater depth of the groove 120, which can accommodate more bare battery cells 200, thereby increasing the energy density of the battery 10.

[0063] In some embodiments, the electrical device includes the battery 10 of any of the above embodiments. Specifically, the groove wall of the groove 120 includes a transition sidewall 130, the bare cell 200 includes a thinned portion 220, the bare cell 200 is disposed in the groove 120, the thinned portion 220 and the transition sidewall 130 correspond to each other, the protrusion of the negative electrode 700 is located in the thinned portion 220, the protrusion of the negative electrode 700 can overlap the transition sidewall 130, the transition sidewall 130 can effectively prevent the protrusion of the negative electrode 700 from contacting the metal layer 400, thereby enabling the battery 10 to have higher safety reliability, charging window and energy density. Furthermore, the electrical device having this battery 10 has higher reliability.

[0064] Experimental Example

[0065] I. Performance Testing Methods

[0066] 1) Capacity: 0.5C constant current and constant voltage charging to the upper limit voltage, 0.02C cutoff; 0.2C constant current discharging to the cutoff voltage.

[0067] 2) Drop test:

[0068] Full charge of the battery cell: 0.5C constant current and constant voltage charging to the upper limit voltage, 0.02C cutoff.

[0069] 1. Secure the battery cell in the designated clamp and drop it from a height of 1m onto a marble floor;

[0070] 2. Perform directional drops according to the following requirements: drop once from each of the 6 sides and 4 corners, for a total of 10 drops. This constitutes one cycle. 10 cycles need to be performed, for a total of 100 drops.

[0071] 3. After the drop test, immediately test the OCV1 / IMP1 of the battery cell. After placing it at room temperature for 24 hours, test OCV2 and IMP2. The test must pass the following standards: A. No fire, no explosion, no leakage; and B. ΔV ≤ 0.1V (ΔV = OCV1 - OCV2).

[0072] 3) Charging window test method:

[0073] Test the charging window using different charging rates, and ensure that the disassembly interface does not deposit lithium.

[0074] 2.8C constant current 4.50V, 2.0C constant current 4.53V, 0.05C cutoff; 1C constant current discharge 3.0V, 5min rest between steps, 20 cycles;

[0075] 3.0C constant current 4.50V, 2.2C constant current 4.53V, 0.05C cutoff; 1C constant current discharge 3.0V, 5min rest between steps, 20 cycles;

[0076] 3.2C constant current 4.50V, 2.4C constant current 4.53V, 0.05C cutoff; 1C constant current discharge 3.0V, 5min rest between steps, 20 cycles;

[0077] 3.4C constant current 4.50V, 2.6C constant current 4.53V, 0.05C cutoff; 1C constant current discharge 3.0V, 5min rest between steps, 20 cycles;

[0078] 3.5C constant current 4.50V, 2.7C constant current 4.53V, 0.05C cutoff; 1C constant current discharge 3.0V, rest for 5min between steps, cycle 20 times;

[0079] 3.7C constant current 4.50V, 2.9C constant current 4.53V, 0.05C cutoff; 1C constant current discharge 3.0V, 5min rest between steps, 20 cycles.

[0080] 4) Energy density improvement rate = (Xn-X1) / X1×100%, where X1 is the energy density of control group 1 and Xn is the energy density of other control groups and experimental groups.

[0081] II. Experimental Group

[0082] Experimental tests were conducted using a conventional wound-type soft-pack lithium-ion battery with dimensions of 4.82 mm (Max thickness) × 63.38 mm (Max width) × 88 mm (Max length). The encapsulating aluminum-plastic film structure consisted of an outer PA layer, a middle Al layer, and an inner PP layer, with the PP layer having a thickness of 45 μm. Different treatments were applied to the aluminum-plastic film and the two edges of the positive and negative electrode sheets in the width direction of the above soft-pack lithium-ion battery to form the following test samples:

[0083] In control group 1, the aluminum-plastic film and the positive and negative electrode sheets were not thinned in any way. In the bare cell, the dimension of the portion of the negative electrode sheet that extends beyond the positive electrode sheet (i.e., the protruding portion) along either side of the electrode sheet width direction was 0.8 mm.

[0084] Control group 2 differs from control group 1 only in that: Control group 2 further removes a portion of the PP layer from the aluminum-plastic film, resulting in grooves on both sides of the storage cavity wall in the direction of the bare battery cell thickness. The size of the grooves matches the size of the bare battery cell to accommodate it, and the depth of the grooves is equal to the thickness of the PP layer. The groove 120 does not have a transition sidewall 130. In other words, the bare battery cell 200 does not have a thinned portion 220, and the groove 120 on the storage cavity 110 is simply a regular sidewall. For details, please refer to... Figure 9 .

[0085] Control group 3 differs from control group 2 only in that: control group 3 further treats the sidewalls of the groove, creating a stepped transition sidewall structure on the sidewalls corresponding to the width directions of the positive and negative electrodes of the bare cell, such as... Figure 3 As shown above, details will not be repeated here. Along the thickness direction of the bare cell, the dimension of the first wall 131 is H1, the dimension of the PP layer is H2, and the horizontal distance between the first wall and the third wall is 5mm. Note: Along the thickness direction of the bare cell, the projected area of ​​the transition sidewall + the projected area of ​​the bottom wall = the projected area of ​​the groove in control group 2.

[0086] The only difference between experimental groups 1-6 and control group 3 is that experimental groups 1-6 also underwent gradient thinning on both sides of the width direction of the positive and negative electrode sheets, as detailed above. In the positive electrode sheet, the thickness of the first thinned region located at the first region point is W1, and the thickness of the first main body region is W2. In the negative electrode sheet, the thickness of the second thinned region located at the second region point is W3, and the thickness of the second main body region is W4.

[0087] The only difference between experimental groups 7-10 and experimental group 5 is the size of the first wall 131.

[0088] Specifically, please refer to the table below, where " / " indicates that the parameter or performance is not available.

[0089]

[0090] The table above shows that when battery 10 includes the thinned portion 220 and the groove 120 includes the transition sidewall 130, the charging window and safety reliability of battery 10 can be effectively improved. Furthermore, when 0.94W2≤W1<W2 and 0.94W4≤W3<W4, the energy density of battery 10 is also improved. A larger charging window indicates better charging performance, allowing for a higher charging rate and improved battery charging performance.

[0091] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention. Furthermore, the embodiments of the present invention and the features thereof can be combined with each other unless otherwise specified.

Claims

1. A battery, characterized in that, include: A bare battery cell includes a main body and a thinned portion with a thickness less than that of the main body. The thinned portion is connected to the end of the main body. The negative electrode of the bare battery cell has a protruding portion located inside the thinned portion. Along the thickness direction of the bare battery cell, the projection of the protruding portion does not overlap with the projection of the positive electrode of the bare battery cell. An encapsulation film includes a metal layer and an insulating layer stacked sequentially. The encapsulation film has a storage cavity for accommodating the bare battery cell. The cavity wall has a groove on at least one side in the thickness direction of the bare battery cell. The groove includes a bottom wall formed at least partially by the metal layer and a transition sidewall formed by the insulating layer. The transition sidewall surrounds a circumferential edge connected to the bottom wall and has a first edge away from the bottom wall and a second edge close to the bottom wall. The first edge and the second edge are offset in the thickness direction of the bare battery cell. Along the thickness direction of the bare cell, at least a portion of the projection of the protrusion falls within the projection range of the transition sidewall, and the projection of the main body falls within the projection range of the bottom wall.

2. The battery according to claim 1, characterized in that, The transition sidewall is a stepped structure or a sloping structure.

3. The battery according to claim 2, characterized in that, The transition sidewall is a stepped structure, which includes a first wall, a second wall and a third wall. One end of the second wall is connected to the first wall and the other end is connected to the third wall. The second wall forms a stepped surface. The end of the first wall away from the second wall constitutes the first edge, and the end of the third wall away from the second wall constitutes the second edge.

4. The battery according to claim 3, characterized in that, Along the thickness direction of the bare cell, the size of the first wall is H1, the size of the insulating layer is H2, 0.1H2≤H1≤0.8H2; and / or, the horizontal distance between the first wall and the third wall is 2 to 10 mm.

5. The battery according to claim 2, characterized in that, The transition sidewall is a sloping structure, and the horizontal distance between the first edge and the second edge is 2 to 10 mm.

6. The battery according to claim 1, characterized in that, The bare cell has a wound structure. The positive electrode sheet includes a positive current collector and a positive electrode film layer disposed on at least one side surface of the positive current collector. The positive electrode film layer includes a first thinned region and a first main body region. The first thinned region is connected to both ends of the first main body region in the width direction. The first thinned region forms part of the thinned portion, and the first main body region forms part of the main body portion.

7. The battery according to claim 6, characterized in that, The negative electrode sheet includes a negative electrode current collector and a negative electrode film layer disposed on at least one side surface of the negative electrode current collector. The negative electrode film layer includes a second thinning region and a second main body region. The second thinning region is connected to both ends of the second main body region in the width direction. The second thinning region forms a portion of the thinned portion. The second thinning region includes the protruding portion. The second main body region forms a portion of the main body region.

8. The battery according to claim 1, characterized in that, The bare cell has a stacked structure. The positive electrode includes a positive current collector and a positive electrode film layer disposed on at least one side surface of the positive current collector. The positive electrode film layer includes a first thinned region and a first main body region. The first thinned region is connected to both ends of the first main body region in the length direction and both ends of the first main body region in the width direction. The first thinned region forms part of the thinned portion, and the first main body region forms part of the main body portion.

9. The battery according to claim 8, characterized in that, The negative electrode sheet includes a negative electrode current collector and a negative electrode film layer disposed on at least one side surface of the negative electrode current collector. The negative electrode film layer includes a second thinning region and a second main body region. The second thinning region is connected to both ends of the second main body region in the length direction and both ends of the second main body region in the width direction. The second thinning region forms a portion of the thinned portion and includes the protruding portion. The second main body region forms a portion of the main body region.

10. The battery according to claim 7 or 9, characterized in that, Along the thickness direction of the bare cell, a portion of the second thinning region is projected onto the transition sidewall, and another portion of the second thinning region is projected onto the first thinning region.

11. The battery according to claim 10, characterized in that, Along the thickness direction of the bare cell, at least a portion of the projection of the first thinning region falls on the transition sidewall.

12. The battery according to claim 6 or 8, characterized in that, A first region point is defined on the first thinning area. The distance between the first region point and the end of the first thinning area away from the first main body area is D, where D = 5 mm. The thickness of the first thinning area located at the first region point is W1, and the thickness of the first main body area is W2, where 0.88W2 < W1 < W2.

13. The battery according to claim 12, characterized in that, 0.94W2≤W1<W2.

14. The battery according to claim 7 or 9, characterized in that, A second region point is defined on the second thinning region. The distance between the second region point and the end of the second thinning region away from the second main body region is E, where E = 5 mm. The thickness of the second thinning region located at the second region point is W3, and the thickness of the second main body region is W4, where 0.88W4 < W3 < W4.

15. The battery according to claim 14, characterized in that, 0.94W4≤W3<W4.

16. The battery according to any one of claims 1 to 9, characterized in that, The battery further includes at least one of the following (1)-(4): (1) The outermost electrode of the bare cell in its thickness direction is the positive electrode; (2) The encapsulation film further includes a protective layer, which is disposed on the side of the metal layer away from the insulating layer. The protective layer includes a nylon layer; (3) The metal layer includes an Al layer; (4) The insulating layer includes a PP layer.

17. Electrical equipment, characterized in that, The battery includes any one of claims 1 to 16.

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