Z-shaped continuous folding battery cell, battery, electric equipment and battery cell manufacturing method

Abstract

The invention belongs to the field of design or manufacturing of batteries, and particularly relates to a Z-shaped continuous folding battery cell, a battery, electric equipment and a battery cell manufacturing method. In order to improve the yield and the performance of a battery cell, the invention provides a Z-shaped continuous folding battery cell. The Z-shaped continuous folding battery cell comprises a Z-shaped composite pole piece which is folded in a reciprocating manner, the composite pole piece is provided with at least two parallel first parts, a first positive plate is arranged between any two adjacent first parts, the composite pole piece comprises a second positive plate and a negative plate, and the second positive plate is arranged between any two adjacent negative plates. The invention also discloses a battery comprising the Z-shaped continuous folding battery cell, electric equipment and a manufacturing method of the Z-shaped continuous folding battery cell. The composite pole piece internally comprises continuous positive and negative pole pieces, and the sizes of the pole pieces are consistent, so that the number of notches is reduced, the probability of burr occurrence is reduced, the utilization rate of the positive and negative pole pieces is improved, and the yield and the performance of the battery cell are improved.

Description

Technical Field

[0001] The invention belongs to the field of battery design or manufacturing, and in particular relates to a Z-shaped continuously folded battery cell, a battery, an electrical device and a battery cell manufacturing method. Background Art

[0002] In the prior art, battery cells are mainly divided into laminated battery cells and wound battery cells. Among them, laminated battery cells are formed by stacking multiple pole sheets in sequence. Before stacking, multiple pole sheets need to be cut out. During the cutting process, burrs will appear on the cutting edges of the pole sheets. Once there are burrs on the cutting edges of the pole sheets, the battery cell is a low-quality battery cell with safety hazards. At the same time, in order to ensure safety, each layer of the laminated battery cell has the phenomenon of negative over positive (negative pole sheet exceeds positive pole sheet), resulting in the positive and negative pole sheets not being fully utilized, affecting the energy density of the battery cell; wound battery cells are formed by winding pole sheets. During the winding process, the winding needle drives the pole sheet to be wound into a roll. Since the shape of the winding needle is square or diamond, the winding needle will give the pole sheet a velocity component similar to a sine direction during the winding process, thereby causing the tension of the pole sheet to fluctuate. At the same time, the sizes of the inner and outer circles of the wound battery cell are inconsistent, and the battery cell is easy to deform after being baked. The deformed battery cell has safety hazards.

[0003] In order to improve the yield rate of battery cells as much as possible and avoid safety hazards of battery cells, a Chinese utility model patent with authorization announcement number CN220233266U and authorization announcement date 2023.12.22 discloses a Z-type stacked battery cell, which includes a "Z"-shaped reciprocating folded negative electrode sheet, the negative electrode sheet includes multiple parallel first parts and a bent part connecting two adjacent first parts, and a composite electrode sheet is provided between the two first parts, and the composite electrode sheet includes a positive electrode sheet and a diaphragm wrapped on the outer surface of the positive electrode sheet.

[0004] In the above-mentioned Z-type stacked battery cell, the negative electrode sheet is a whole electrode sheet that has not been cut, which can reduce the number of cutting times, thereby reducing the probability of burrs appearing in the battery cell and improving the yield rate of the battery cell.

[0005] However, in the above-mentioned Z-type stacked battery cell, on the one hand, all positive electrode sheets need to be formed by cutting, and the number of cutting times is still relatively large, which leads to a high probability of burrs appearing, and further leads to a high incidence of safety hazards in the battery cell; on the other hand, at the bent part of the negative electrode sheet, there is no positive electrode sheet facing the negative electrode sheet, and both the positive and negative electrode sheets cannot be fully utilized, resulting in a low energy density of the battery cell. Summary of the invention

[0006] The object of the present invention is to provide a Z-shaped continuously folded battery cell to solve the technical problems of low energy density and high incidence of potential safety hazards in existing wound and laminated battery cells.

[0007] The object of the present invention is to provide a battery to solve the same technical problem as above.

[0008] The object of the present invention is to provide an electrical device to solve the same technical problem as above.

[0009] The object of the present invention is to provide a method for manufacturing a battery cell to solve the same technical problem as above.

[0010] To achieve the above purpose, the technical solution of the Z-type continuous folding battery cell provided by the present invention is: A Z-shaped continuously folded battery cell comprises a first electrode sheet which is reciprocally folded in a "Z" shape, wherein the first electrode sheet comprises at least two parallel first parts and a bent part connecting two adjacent first parts, a first positive electrode sheet is arranged between any two adjacent first parts, a diaphragm is arranged between the first positive electrode sheet and the first electrode sheet, the first electrode sheet is a composite electrode sheet, the composite electrode sheet comprises a second positive electrode sheet and two negative electrode sheets, the second positive electrode sheet is arranged between the negative electrode sheets, or the composite electrode sheet comprises n second positive electrode sheets and n+1 negative electrode sheets, where n≥2, each second positive electrode sheet is arranged between two different negative electrode sheets; and a diaphragm is arranged between each second positive electrode sheet and the negative electrode sheet.

[0011] Furthermore, the diaphragm is stacked on both sides of the first pole piece.

[0012] Furthermore, all negative electrode sheets have the same length and height, the height of the separator is greater than the height of the negative electrode sheet, the length of the separator is greater than the length of the negative electrode sheet, and the length of the negative electrode sheet is greater than the length of the second positive electrode sheet, and the width of the negative electrode sheet is greater than the width of the second positive electrode sheet.

[0013] Furthermore, one end of the first positive electrode sheet is inserted into the bent portion.

[0014] The beneficial effects of the Z-shaped continuous folding battery cell provided by the present invention are as follows: the present invention is an improved invention. Compared with the prior art, in the present invention, the composite electrode sheet is reciprocatingly folded along the "Z" shape. On the one hand, the second positive electrode sheet in the composite electrode sheet is not cut, which can effectively reduce the number of cuttings, reduce the probability of burrs, improve the yield rate of the battery cell, and reduce the occurrence rate of safety hazards; on the other hand, at the bent part of the composite electrode sheet, the positive electrode sheet and the negative electrode sheet are still facing each other, so the utilization rate of the positive and negative electrode sheets can be improved, and the energy density of the battery cell can be improved.

[0015] In a non-Z-shaped folded stacked battery cell, each cut-out electrode sheet (including positive electrode sheet and negative electrode sheet) has cutouts on the four edges. In the present invention, the presence of the composite electrode sheet reduces the number of cutouts and can reduce the probability of burrs. At the same time, the composite electrode sheet includes continuous positive and negative electrode sheets, and the composite electrode sheet only has the phenomenon of negative over positive at the head and tail ends in the length direction. Compared with the technical solution in which each layer of the stacked battery cell has the phenomenon of negative over positive, the utilization rate of the positive and negative electrode sheets in the present invention is high, which is beneficial to improving the energy density of the Z-shaped continuous folded battery cell.

[0016] Compared with wound batteries, since the Z-type continuous folding battery adopts Z-type continuous folding technology, the size of each layer of the electrode is consistent, there is no problem of inner and outer circles of the wound battery, and the battery deformation is relatively low, which is beneficial to improving the yield and performance of the battery.

[0017] To achieve the above purpose, the technical solution of the battery provided by the present invention is: A battery comprises a battery cell, the battery cell comprises a first electrode sheet folded back and forth in a "Z" shape, the first electrode sheet comprises at least two parallel first parts and a bent part connecting two adjacent first parts, a first positive electrode sheet is arranged between any two adjacent first parts, a diaphragm is arranged between the first positive electrode sheet and the first electrode sheet, the first electrode sheet is a composite electrode sheet, the composite electrode sheet comprises a second positive electrode sheet and two negative electrode sheets, the second positive electrode sheet is arranged between the negative electrode sheets, or the composite electrode sheet comprises n second positive electrode sheets and n+1 negative electrode sheets, n≥2, each second positive electrode sheet is arranged between two different negative electrode sheets; and a diaphragm is arranged between each second positive electrode sheet and the negative electrode sheet.

[0018] Furthermore, the diaphragm is stacked on both sides of the first pole piece.

[0019] Furthermore, all negative electrode sheets have the same length and height, the height of the separator is greater than the height of the negative electrode sheet, the length of the separator is greater than the length of the negative electrode sheet, and the length of the negative electrode sheet is greater than the length of the second positive electrode sheet, and the width of the negative electrode sheet is greater than the width of the second positive electrode sheet.

[0020] Furthermore, one end of the first positive electrode sheet is inserted into the bent portion.

[0021] The battery provided by the present invention has the following beneficial effects: the present invention is an improved invention. Compared with the prior art, in the present invention, in the battery cell, the composite electrode is folded back and forth along the "Z" shape. On the one hand, the second positive electrode in the composite electrode is not cut, which can effectively reduce the number of cuttings, reduce the probability of burrs, improve the yield rate of the battery cell, and reduce the incidence of safety hazards; on the other hand, at the bent part of the composite electrode, there is still a positive electrode and a negative electrode facing each other, so the utilization rate of the positive and negative electrodes can be improved, and the energy density of the battery cell can be improved.

[0022] In a non-Z-shaped folded stacked battery cell, each cut-out electrode sheet (including positive electrode sheet and negative electrode sheet) has cutouts on the four edges. In the present invention, the presence of the composite electrode sheet reduces the number of cutouts and can reduce the probability of burrs. At the same time, the composite electrode sheet includes continuous positive and negative electrode sheets, and the composite electrode sheet only has the phenomenon of negative over positive at the head and tail ends in the length direction. Compared with the technical solution in which each layer of the stacked battery cell has the phenomenon of negative over positive, the utilization rate of the positive and negative electrode sheets in the present invention is high, which is beneficial to improving the energy density of the Z-shaped continuous folded battery cell.

[0023] Compared with wound batteries, since the Z-type continuous folding battery adopts Z-type continuous folding technology, the size of each layer of the electrode is consistent, there is no problem of inner and outer circles of the wound battery, and the battery deformation is relatively low, which is beneficial to improving the yield and performance of the battery.

[0024] To achieve the above purpose, the technical solution of the electrical equipment provided by the present invention is: An electrical device includes a battery, the battery includes a battery cell, the battery cell includes a first electrode sheet folded back and forth in a "Z" shape, the first electrode sheet has at least two parallel first parts and a bent part connecting two adjacent first parts, a first positive electrode sheet is arranged between any two adjacent first parts, a diaphragm is arranged between the first positive electrode sheet and the first electrode sheet, the first electrode sheet is a composite electrode sheet, the composite electrode sheet includes a second positive electrode sheet and two negative electrode sheets, the second positive electrode sheet is arranged between the negative electrode sheets, or the composite electrode sheet includes n second positive electrode sheets and n+1 negative electrode sheets, n≥2, each second positive electrode sheet is arranged between two different negative electrode sheets; and a diaphragm is arranged between each second positive electrode sheet and the negative electrode sheet.

[0025] Furthermore, the diaphragm is stacked on both sides of the first pole piece.

[0026] Furthermore, all negative electrode sheets have the same length and height, the height of the separator is greater than the height of the negative electrode sheet, the length of the separator is greater than the length of the negative electrode sheet, and the length of the negative electrode sheet is greater than the length of the second positive electrode sheet, and the width of the negative electrode sheet is greater than the width of the second positive electrode sheet.

[0027] Furthermore, one end of the first positive electrode sheet is inserted into the bent portion.

[0028] The beneficial effects of the electrical equipment provided by the present invention are as follows: the present invention is an improved invention. Compared with the prior art, in the present invention, in the battery cell of the electrical equipment, the composite electrode is folded back and forth along the "Z" shape. On the one hand, the second positive electrode in the composite electrode is not cut, which can effectively reduce the number of cuttings, reduce the probability of burrs, improve the yield rate of the battery cell, and reduce the incidence of safety hazards; on the other hand, at the bent part of the composite electrode, there is still a positive electrode and a negative electrode facing each other, so the utilization rate of the positive and negative electrodes can be improved, and the energy density of the battery cell can be improved.

[0029] In a non-Z-shaped folded stacked battery cell, each cut-out electrode sheet (including positive electrode sheet and negative electrode sheet) has cutouts on the four edges. In the present invention, the presence of the composite electrode sheet reduces the number of cutouts and can reduce the probability of burrs. At the same time, the composite electrode sheet includes continuous positive and negative electrode sheets, and the composite electrode sheet only has the phenomenon of negative over positive at the head and tail ends in the length direction. Compared with the technical solution in which each layer of the stacked battery cell has the phenomenon of negative over positive, the utilization rate of the positive and negative electrode sheets in the present invention is high, which is beneficial to improving the energy density of the Z-shaped continuous folded battery cell.

[0030] Compared with wound batteries, since the Z-type continuous folding battery adopts Z-type continuous folding technology, the size of each layer of the electrode is consistent, there is no problem of inner and outer circles of the wound battery, and the battery deformation is relatively low, which is beneficial to improving the yield and performance of the battery.

[0031] To achieve the above-mentioned purpose, the technical solution of the battery cell manufacturing method provided by the present invention is: A method for manufacturing a battery cell includes a folding step for folding a first electrode sheet back and forth in a "Z" shape. In the folding step, a first positive electrode sheet is loaded between two adjacent parallel first parts. Before the folding step, a stacking step is also provided. In the stacking step, a negative electrode sheet, a second positive electrode sheet and a separator are stacked together to form the first electrode sheet. When the number of the second positive electrode sheet is one, there are two negative electrode sheets. During the stacking process, the second positive electrode sheet is ensured to be located between the two negative electrode sheets. When the number of the second positive electrode sheets is n, n≥2, and the number of the negative electrode sheets is n+1, during the stacking process, each second positive electrode sheet is ensured to be located between two different negative electrode sheets.

[0032] Furthermore, in the stacking step, the diaphragm is stacked on both sides of the first pole piece.

[0033] Furthermore, all negative electrode sheets have the same length and height, the height of the separator is greater than the height of the negative electrode sheet, the length of the separator is greater than the length of the negative electrode sheet, and the length of the negative electrode sheet is greater than the length of the second positive electrode sheet, and the width of the negative electrode sheet is greater than the width of the second positive electrode sheet.

[0034] Furthermore, in the folding step, one end of the first positive electrode sheet is inserted into the bent portion.

[0035] The beneficial effects of the battery cell manufacturing method provided by the present invention are as follows: the present invention is an improved invention. Compared with the prior art, in the present invention, the composite electrode is folded back and forth along the "Z" shape. On the one hand, the second positive electrode in the composite electrode is not cut, which can effectively reduce the number of cuttings, reduce the probability of burrs, improve the yield rate of the battery cell, and reduce the incidence of safety hazards; on the other hand, at the bent part of the composite electrode, there is still a positive electrode and a negative electrode facing each other, so the utilization rate of the positive and negative electrodes can be improved, and the energy density of the battery cell can be improved.

[0036] In a non-Z-shaped folded stacked battery cell, each cut-out electrode sheet (including positive electrode sheet and negative electrode sheet) has cutouts on the four edges. In the present invention, the presence of the composite electrode sheet reduces the number of cutouts and can reduce the probability of burrs. At the same time, the composite electrode sheet includes continuous positive and negative electrode sheets, and the composite electrode sheet only has the phenomenon of negative over positive at the head and tail ends in the length direction. Compared with the technical solution in which each layer of the stacked battery cell has the phenomenon of negative over positive, the utilization rate of the positive and negative electrode sheets in the present invention is high, which is beneficial to improving the energy density of the Z-shaped continuous folded battery cell.

[0037] Compared with wound batteries, since the Z-type continuous folding battery adopts Z-type continuous folding technology, the size of each layer of the electrode is consistent, there is no problem of inner and outer circles of the wound battery, and the battery deformation is relatively low, which is beneficial to improving the yield and performance of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is a schematic diagram of the structure of the Z-type continuous folding battery cell before shaping; Figure 2 It is a front view schematic diagram of the Z-type continuous folding battery cell of the present invention; Description of reference numerals: 1. First positive electrode sheet; 2. Separator; 3. Negative electrode sheet; 4. Second positive electrode sheet; 5. Adhesive tape; 6. Positive electrode ear; 7. Negative electrode ear. DETAILED DESCRIPTION

[0039] In order to solve the problems in the background technology, the core inventive concept of the present invention is: replacing the negative electrode sheet with a composite electrode sheet that includes both the positive electrode sheet and the negative electrode sheet, thereby further reducing the number of cutting times, reducing the probability of burrs appearing, improving the yield rate of the battery cell, and reducing the occurrence rate of safety hazards; at the bent part of the composite electrode sheet, the positive electrode sheet and the negative electrode sheet are still facing each other, so the utilization rate of the positive and negative electrode sheets can be improved, and the energy density of the battery cell can be improved; at the same time, because the battery cell adopts Z-type continuous folding technology, the size of each layer of the electrode sheet is consistent, there is no problem of winding the inner and outer circles of the battery, the deformation of the battery cell is relatively low, and the yield rate and performance of the battery cell can be effectively improved.

[0040] The present invention is further described in detail below in conjunction with embodiments.

[0041] Specific embodiments of the Z-type continuous folding battery cell provided by the present invention: like Figure 1~2 As shown, the Z-type continuous folded battery cell includes a first electrode sheet that is reciprocatingly folded in a "Z" shape, the first electrode sheet having at least two parallel first parts and a bent part connecting two adjacent first parts, a first positive electrode sheet 1 is arranged between any two adjacent first parts, a diaphragm 2 is arranged between the first positive electrode sheet 1 and the first electrode sheet, the first electrode sheet is a composite electrode sheet with a continuous length, and the first positive electrode sheet 1 is a single sheet with a set width.

[0042] In a first specific implementation, the composite electrode sheet includes a second positive electrode sheet 4 with a continuous length and two negative electrode sheets 3 with a continuous length, and the second positive electrode sheet 4 is arranged between the negative electrode sheets 3 .

[0043] In a second specific embodiment, the composite electrode sheet includes n second positive electrode sheets 4 with continuous length and n+1 negative electrode sheets 3 with continuous length, n≥2, and each second positive electrode sheet 4 is respectively arranged between two different negative electrode sheets 3. Among them, n can be 2, 3, 4 or a larger value.

[0044] In the above two specific embodiments, a separator 2 is provided between each second positive electrode sheet 4 and each negative electrode sheet 3 .

[0045] In the present invention, the first positive electrode sheet 1 is a cut positive electrode sheet (i.e., a single sheet of a set width), and the second positive electrode sheet 4 is an uncut positive electrode sheet (i.e., a positive electrode sheet of continuous length); depending on the number of bending times, the number of the first part can also be two, three or more, and the corresponding number of the first positive electrode sheets 1 is one, two or more, respectively, which will not be repeated here.

[0046] It should be noted that if Figure 1 As shown, in the composite electrode sheet, the negative electrode sheet 3 is longer than the second positive electrode sheet 4. This is to ensure the technical requirement that the negative electrode always exceeds the positive electrode (hereinafter referred to as negative exceeding positive) to ensure the safety of the battery cell. This is common knowledge to those skilled in the art and will not be repeated here.

[0047] Since the first positive electrode sheet 1 is arranged between two adjacent first parts, it can ensure that the negative electrode sheet 3 always exceeds the first positive electrode sheet 1 (i.e., ensure that the negative exceeds the positive). At the same time, for any positive electrode sheet, both sides of the positive electrode sheet are opposite to the negative electrode sheet 3; for the outermost negative electrode sheet 3, one side of the negative electrode sheet 3 is opposite to the first positive electrode sheet 1, and the other side is opposite to the second positive electrode sheet 4; if there is a negative electrode sheet 3 located in the inner layer, then for the negative electrode sheet 3 in the inner layer, the two sides of the negative electrode sheet 3 are opposite to different second positive electrode sheets 4 respectively. Therefore, in the present invention, both sides of the positive and negative electrode sheets are fully utilized, and the utilization rate of the positive and negative electrode sheets is high, which is conducive to improving the energy density of the battery cell.

[0048] When the pole pieces are folded, ensure that the positive pole ears 6 of all positive pole pieces are arranged opposite to each other, and ensure that the negative pole ears 7 of all negative pole pieces 3 are arranged opposite to each other, so as to facilitate further processing of the pole ears later; after folding, the stacked pole pieces are hot pressed and cold pressed, and the pole pieces are fixed with tape 5.

[0049] Compared with the prior art, in the present invention, the composite electrode sheet is folded back and forth in a "Z" shape. On the one hand, the second positive electrode sheet 4 in the composite electrode sheet is not cut, which can effectively reduce the number of cutting times, reduce the probability of burrs, improve the yield rate of the battery cell, and reduce the occurrence rate of safety hazards; on the other hand, at the bent part of the composite electrode sheet, the positive electrode sheet and the negative electrode sheet 3 are still facing each other, so the utilization rate of the positive and negative electrode sheets can be improved, and the energy density of the battery cell can be improved.

[0050] In a non-Z-shaped folded stacked battery cell, each cut-out electrode sheet (including positive electrode sheet and negative electrode sheet) has cutouts on the four edges. In the present invention, the presence of the composite electrode sheet reduces the number of cutouts and can reduce the probability of burrs. At the same time, the composite electrode sheet includes continuous positive and negative electrode sheets, and the composite electrode sheet only has the phenomenon of negative over positive at the head and tail ends in the length direction. Compared with the technical solution in which each layer of the stacked battery cell has the phenomenon of negative over positive, the utilization rate of the positive and negative electrode sheets in the present invention is high, which is beneficial to improving the energy density of the Z-shaped continuous folded battery cell.

[0051] Compared with wound batteries, since the Z-type continuous folding battery adopts Z-type continuous folding technology, the size of each layer of the electrode is consistent, there is no problem of inner and outer circles of the wound battery, and the battery deformation is relatively low, which is beneficial to improving the yield and performance of the battery.

[0052] In a specific embodiment, the diaphragm 2 is stacked on both sides of the first pole piece, and the structure is simple.

[0053] In another specific embodiment, referring to the utility model patent with authorization announcement number CN220233266U, the diaphragm 2 is wrapped on the outer surface of the first positive electrode sheet 1, so that the diaphragm 2 on the first positive electrode sheet 1 does not need to be folded, and wrinkles of the diaphragm 2 can be effectively avoided.

[0054] Preferably, in a specific implementation, the lengths and heights of all negative electrode sheets 3 are the same, the structure is simple, and the utilization rates of the positive and negative electrode sheets are high.

[0055] However, in other specific embodiments, the length and height of the negative electrode sheet 3 may be different. In this case, the height and length of the second positive electrode sheet 4 are respectively smaller than the minimum length and minimum height of the negative electrode sheet 3 to ensure that the negative exceeds the positive.

[0056] Preferably, in a specific implementation, the height of the inserted first positive electrode sheet 1 is consistent with the height of the stacked second positive electrode sheet 4. In this case, the utilization rate of the positive and negative electrode sheets is high.

[0057] However, in other specific embodiments, the height of the first positive electrode sheet 1 may also be greater than the height of the second positive electrode sheet 4, or, the height of the first positive electrode sheet 1 may also be less than the height of the second positive electrode sheet 4, as long as the technical requirements of negative super-positive are met. The smaller the height difference between the first positive electrode sheet 1 and the second positive electrode sheet 4, the higher the utilization rate of the positive and negative electrode sheets.

[0058] Reference Figure 1 As shown, in a specific embodiment, one end of the first positive electrode sheet 1 is inserted into the bent portion to further increase the utilization rate of the positive and negative electrode sheets.

[0059] Preferably, the width of the first positive electrode sheet 1 is greater than the width of the first portion, so as to further increase the utilization rate of the positive and negative electrode sheets.

[0060] It should be noted that: Figure 1 This is a schematic diagram of the structure of the Z-shaped continuous folded battery cell before shaping. After hot pressing and cold pressing, the width of the first part will become larger and the size of the bent part will become smaller.

[0061] In other specific embodiments, in the thickness direction, the projection of the first positive electrode sheet 1 on the negative electrode sheet 3 completely falls into the area corresponding to the negative electrode sheet 3 and the first part, that is, the first positive electrode sheet 1 is not inserted into the bent part. At this time, the first positive electrode sheet 1 can be prevented from excessively squeezing the diaphragm 2 at the bent part, thereby preventing the diaphragm 2 from being damaged.

[0062] In other specific embodiments, when one end of the first positive electrode sheet 1 is inserted into the bent portion, the width of the first positive electrode sheet 1 is smaller than the width of the first portion to better ensure that the negative exceeds the positive.

[0063] Of course, when one end of the first positive electrode sheet 1 is inserted into the bent portion, in order to avoid damage to the separator 2, the end of the first positive electrode sheet 1 inserted into the bent portion may also be polished to be smooth.

[0064] Preferably, in a specific implementation, when the number of the second positive electrode sheets 4 is greater than two, the heights and widths of all the second positive electrode sheets 4 are the same, the structure is simple, and the utilization rates of the positive and negative electrode sheets are high.

[0065] However, in other specific embodiments, the height and width of different second positive electrode sheets 4 may also be different. In this case, the height and width of the negative electrode sheet 3 need to be greater than the maximum height and maximum width of the second positive electrode sheet 4 to ensure that the negative exceeds the positive.

[0066] Specific embodiments of the battery provided by the present invention: The battery includes a battery cell, and the battery cell is any one of the specific embodiments of the battery cell of the present invention, which will not be described in detail here.

[0067] Specific embodiments of the electrical equipment provided by the present invention: The electrical device includes a battery, and the battery is a battery in a specific embodiment of the battery of the present invention, which will not be described in detail here.

[0068] Specific embodiments of the battery cell manufacturing method provided by the present invention: The battery cell manufactured by the battery cell manufacturing method of the present invention is a battery cell in a specific embodiment of the battery cell of the present invention, specifically: the battery cell manufacturing method includes a folding step for folding the first electrode sheet back and forth in a "Z" shape, in which the first positive electrode sheet 1 is loaded between two adjacent parallel first parts (one first positive electrode sheet 1 is loaded each time the folding is performed), and before the folding step, there is also a stacking step, in which the negative electrode sheet 3, the second positive electrode sheet 4 and the separator 2 are stacked together to form the first electrode sheet.

[0069] Among them, when the number of second positive electrode sheets 4 is one, there are two negative electrode sheets 3. During the stacking process, it is ensured that the second positive electrode sheet 4 is located between the two negative electrode sheets 3. When the number of second positive electrode sheets 4 is n, n≥2, and there are n+1 negative electrode sheets 3. During the stacking process, it is ensured that each second positive electrode sheet 4 is located between two different negative electrode sheets 3. n can be equal to 2, 3, 4 or a larger value.

[0070] After the folding step is completed, the folded electrode needs to be hot-pressed and cold-pressed, and the electrode needs to be fixed with tape.

[0071] In a specific embodiment, a coating step is also included before the folding step. In the coating step, the diaphragm 2 is wrapped on the outer surface of the first positive electrode sheet 1. At this time, the diaphragm 2 on the first positive electrode sheet 1 does not need to be folded in the folding step, which can effectively avoid wrinkles in the diaphragm 2.

[0072] In another specific embodiment, in the stacking step, the diaphragm 2 is stacked on both sides of the first pole piece, and the coating step can be performed simultaneously with the stacking step, which is beneficial to improving production efficiency.

[0073] The stacked positive and negative electrode sheets and the separator 2 must ensure that in terms of height and length: separator 2>negative electrode sheet 3>second positive electrode sheet 4, to ensure that the negative exceeds the positive; the width of the first positive electrode sheet 1 (dimensions include width, height, and thickness) <the width of the negative electrode sheet 3 corresponding to the first part (or the width of the first part, dimensions include width, height, and thickness) to ensure that the negative exceeds the positive.

[0074] At the same time, during the stacking process, the following conditions must be met: the positive and negative electrode sheets are separated by the separator 2, and the outermost layer is the separator 2, and the second outermost layer is the negative electrode sheet 3, so that both sides of the positive and negative electrode sheets can be fully utilized.

[0075] When the above technical requirements are met, it can be ensured that the negative electrode exceeds the positive electrode, and it can be ensured that there is a separator between the negative electrode sheet 3 and the positive electrode sheet.

[0076] Of course, in other specific embodiments, the first positive electrode sheet 1 wrapped with the separator 2 may also be purchased directly.

[0077] Preferably, in a specific embodiment, the length and height of all negative electrode sheets 3 are the same, the height of the diaphragm 2 is greater than the height of the negative electrode sheet 3, the length of the diaphragm 2 is greater than the length of the negative electrode sheet 3, and the length of the negative electrode sheet 3 is greater than the length of the second positive electrode sheet 4, and the width of the negative electrode sheet 3 is greater than the width of the second positive electrode sheet 4, thereby improving the utilization rate of the positive and negative electrode sheets.

[0078] However, in other specific embodiments, the lengths and heights of different negative electrode sheets 3 may also be different, the height and width of the diaphragm 2 are greater than the maximum height and maximum width of the negative electrode sheet 3, and the maximum height and maximum width of the second positive electrode sheet 4 are less than the minimum height and minimum width of the negative electrode sheet 3, so as to ensure that diaphragms are provided between the negative super positive and the negative electrode sheets and other structures (mainly the packaging film of the positive electrode sheet and the battery cell, the packaging film is preferably an aluminum-plastic film).

[0079] Preferably, in order to further improve the utilization rate of the positive and negative electrode sheets, in a specific embodiment, in the folding step, one end of the first positive electrode sheet 1 is inserted into the bent portion.

[0080] After hot pressing and cold pressing, one end of the first positive electrode sheet 1 may still be inserted into the bent portion; or, because the width of the first portion increases and the size of the bent portion decreases, the first positive electrode sheet 1 is not inserted into the bent portion.

[0081] However, in other specific embodiments, in the folding step, in the thickness direction, the projection of the first positive electrode sheet 1 on the negative electrode sheet 3 completely falls into the area corresponding to the negative electrode sheet 3 and the first part, that is, the first positive electrode sheet 1 is not inserted into the bent part. During folding, the first positive electrode sheet 1 can be prevented from excessively squeezing the diaphragm 2 at the bent part, thereby preventing the diaphragm 2 from being damaged.

[0082] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions recorded in the aforementioned embodiments without creative work, or replace some of the technical features therein by equivalents, thereby combining the attached Figure 1~2 The specific implementation methods given in the specification are, of course, those skilled in the art can also combine the specific implementation methods not given in the other drawings of the specification. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A Z-shaped continuous folded battery cell, comprising a first pole piece that is reciprocatingly folded in a "Z" shape, wherein the first pole piece has at least two parallel first portions and a bent portion connecting two adjacent first portions, a first positive pole piece is disposed between any two adjacent first portions, and a diaphragm is disposed between the first positive pole piece and the first pole piece, characterized in that: The first electrode sheet is a composite electrode sheet, which includes a second positive electrode sheet and two negative electrode sheets, and the second positive electrode sheet is arranged between the negative electrode sheets, or the composite electrode sheet includes n second positive electrode sheets and n+1 negative electrode sheets, n≥2, and each second positive electrode sheet is respectively arranged between two different negative electrode sheets; a diaphragm is provided between each second positive electrode sheet and the negative electrode sheet.

2. The Z-shaped continuous folded battery cell according to claim 1, characterized in that: The diaphragms are stacked on both sides of the first pole piece.

3. The Z-shaped continuous folded battery cell according to claim 2, characterized in that: All negative electrode sheets have the same length and height, the height of the separator is greater than the height of the negative electrode sheet, the length of the separator is greater than the length of the negative electrode sheet, and the length of the negative electrode sheet is greater than the length of the second positive electrode sheet, and the width of the negative electrode sheet is greater than the width of the second positive electrode sheet.

4. The Z-type continuously folded battery cell according to any one of claims 1 to 3, characterized in that: One end of the first positive electrode sheet is inserted into the bent portion.

5. A battery, comprising a battery cell, characterized in that: The battery cell is a Z-shaped continuously folded battery cell as described in any one of claims 1 to 4.

6. An electrical device, comprising a battery, characterized in that: The battery is the battery described in claim 5.

7. A method for manufacturing a battery cell, comprising a folding step for folding a first electrode sheet back and forth in a "Z" shape, wherein in the folding step, the first positive electrode sheet is inserted between two adjacent parallel first parts, characterized in that: There is also a stacking step before the folding step. In the stacking step, the negative electrode sheet, the second positive electrode sheet and the separator are stacked together to form a first electrode sheet. When the number of the second positive electrode sheet is one, there are two negative electrode sheets. During the stacking process, it is ensured that the second positive electrode sheet is located between the two negative electrode sheets. When the number of the second positive electrode sheets is n, n≥2, and there are n+1 negative electrode sheets, during the stacking process, it is ensured that each second positive electrode sheet is located between two different negative electrode sheets.

8. The method for manufacturing a battery cell according to claim 7, characterized in that: In the stacking step, the separators are stacked on both sides of the first pole piece.

9. The method for manufacturing a battery cell according to claim 8, characterized in that: All negative electrode sheets have the same length and height, the height of the separator is greater than the height of the negative electrode sheet, the length of the separator is greater than the length of the negative electrode sheet, and the length of the negative electrode sheet is greater than the length of the second positive electrode sheet, and the width of the negative electrode sheet is greater than the width of the second positive electrode sheet.

10. The method for manufacturing a battery cell according to any one of claims 7 to 9, characterized in that: In the folding step, one end of the first positive electrode sheet is inserted into the folded portion.

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