Winding method, winding equipment, battery cell, battery and power utilization device

Abstract

The invention relates to the technical field of battery manufacturing, and particularly discloses a winding method, winding equipment, a battery cell, a battery and a power utilization device.The winding method comprises the steps that a first diaphragm, a first pole piece, a second diaphragm and a second pole piece are wound; wherein the first pole piece comprises two cut pole piece sections which are arranged at an interval, and an adhesive tape for connecting the two cut pole piece sections; and after winding is completed, the first diaphragm, the adhesive tape and the second diaphragm which are stacked are subjected to fusing treatment synchronously, so that the fused first diaphragm, the fused adhesive tape and the fused second diaphragm are fused and connected at the fusing positions. According to the winding method, the winding equipment, the battery cell, the battery and the electric device provided by the invention, the problems that an existing winding method is relatively low in production efficiency, a pole piece is easy to fall powder and puncture a diaphragm, and the pole piece is easy to drift and shift can be effectively solved.

Description

Technical Field

[0001] The present invention relates to the technical field of battery manufacturing, and in particular to a winding method, winding equipment, a battery cell, a battery and an electrical device. Background Art

[0002] The battery cell is made of a cathode sheet, an anode sheet, and two separators which are stacked and then wound. The separator is located between the cathode sheet and the anode sheet to separate the cathode sheet and the anode sheet of the battery to prevent the cathode sheet and the anode sheet from short-circuiting.

[0003] Currently, in battery production, the steps of the winding process are:

[0004] ①Pre-roll the diaphragm 1~2 times;

[0005] ②Then insert the anode sheet and cathode sheet in turn for winding;

[0006] ③After winding is completed, cut the cathode sheet first, continue to wind the anode sheet for one circle to wrap the cathode sheet, then cut the anode sheet, and then cut the diaphragm.

[0007] The above winding method has the following problems:

[0008] ① In order to avoid the position offset between the starting end of the anode sheet and the diaphragm, the diaphragm needs to be pre-rolled first. The step-by-step feeding method of pre-rolling the diaphragm first and then feeding the anode sheet results in low winding production efficiency;

[0009] ② When cutting the anode sheet, active materials and metal burrs that are easy to fall off will be produced on the end surface of the anode sheet. When winding it later, the active materials are easy to scatter everywhere, thus affecting the electrical performance of the battery cell. At the same time, the metal burrs also have a high risk of puncturing the diaphragm, which will also cause the performance of the battery cell to decline;

[0010] ③ The cathode and anode sheets are cut in advance and then fed into the material, which may cause head and tail swinging. That is, when the head of the electrode sheet is fed in and the tail is finished, the end of the electrode sheet after cutting is in a free state, and the electrode sheet is prone to displacement in the width direction (commonly known as "pole sheet offset"). Pole sheet offset may cause overhang in width (Overhang refers to the part of the negative electrode sheet that exceeds the positive and negative electrode sheets in length and width direction). There may be a risk of lithium plating when using cells with poor overhang in batteries.

[0011] Therefore, the existing winding method needs to be improved to solve the problems of low production efficiency, easy powder loss and puncture of the diaphragm of the anode sheet, and easy tail deviation of the anode sheet.

[0012] The above information disclosed in this Background section is included only for enhancement of understanding of the background of the present disclosure and therefore it may contain information that does not form the prior art that is currently known to a person of ordinary skill in the art. Summary of the invention

[0013] One object of the present invention is to provide a winding method, winding equipment, battery cell, battery and electrical device, which can effectively solve the problems of low production efficiency of existing winding methods, easy powder loss and puncture of the diaphragm, and easy tail deviation of the pole piece.

[0014] To achieve the above objectives:

[0015] In a first aspect, a winding method is provided, comprising:

[0016] Winding a first diaphragm, a first pole piece, a second diaphragm, and a second pole piece; wherein the first pole piece comprises two spaced-apart cut pole segments and a tape connecting the two cut pole segments;

[0017] After the winding is completed, the stacked first diaphragm, the adhesive tape, and the second diaphragm are simultaneously subjected to a fusing process, so that the first diaphragm, the adhesive tape, and the second diaphragm after the fusing process are fused and connected at the fusing location.

[0018] In some embodiments, the stacked first diaphragm, the tape, and the second diaphragm are simultaneously subjected to a fusing process, comprising:

[0019] The middle position of the adhesive tape is heat-cut, so that the first diaphragm and the second diaphragm are fused and connected through the middle position of the adhesive tape, and the first diaphragm, the adhesive tape, and the second diaphragm are cut simultaneously.

[0020] In some of these embodiments,

[0021] Before the middle position of the adhesive tape is heat-cut, the middle position of the adhesive tape is heat-pressed first, so that the first diaphragm and the second diaphragm are pre-connected through the middle position of the adhesive tape.

[0022] In some embodiments, fusing the stacked first diaphragm, the tape, and the second diaphragm comprises:

[0023] First, heat-pressing the middle position of the adhesive tape so that the first diaphragm and the second diaphragm are fused and connected through the middle position of the adhesive tape;

[0024] Then, heat cutting is performed at the middle position of the adhesive tape to simultaneously cut the first diaphragm, the adhesive tape, and the second diaphragm.

[0025] In some of these embodiments,

[0026] Before fusion: the thickness of the first diaphragm is D1, the thickness of the second diaphragm is D2, and the thickness of the tape is D3;

[0027] After fusion:

[0028] At the cutting position, the total thickness of the first diaphragm, the second diaphragm and the adhesive tape is T<(D1+D2+D3);

[0029] At a non-cutting position, the total thickness T of the first diaphragm, the second diaphragm and the adhesive tape is (D1+D2+D3).

[0030] In some embodiments, winding the first diaphragm, the first pole piece, the second diaphragm, and the second pole piece includes:

[0031] Firstly align the winding start ends of the first diaphragm, the first pole piece, and the second diaphragm, and then pre-roll them to a preset length;

[0032] inserting the second pole piece for winding;

[0033] Synchronously winding the first diaphragm, the first pole piece, the second diaphragm, and the second pole piece;

[0034] The second pole piece is cut.

[0035] In a second aspect, a winding device is provided, comprising:

[0036] A first cutting mechanism, used for cutting the continuous sheet into two cut pieces;

[0037] A first connecting mechanism, used to connect the two cut electrode segments through an adhesive tape to form a first electrode piece;

[0038] A winding mechanism, used for winding the first diaphragm, the first pole piece, the second diaphragm, and the second pole piece;

[0039] The second cutting mechanism is used to perform a fusing process on the stacked first diaphragm, the adhesive tape, and the second diaphragm, so that the first diaphragm, the adhesive tape, and the second diaphragm after fusing are fused and connected at the fusing position.

[0040] In some embodiments, the second cutting mechanism comprises a hot cutting knife, and the hot cutting temperature of the hot cutting knife is 130°C-300°C.

[0041] In some embodiments, the second cutting mechanism further includes two oppositely disposed heat pressing plates, with a space between the two heat pressing plates for passing through the stacked first diaphragm, the adhesive tape, and the second diaphragm.

[0042] In some embodiments, the hot cutting knife is housed in one of the hot pressing plates, and the hot cutting knife can extend out of or retract into the hot pressing plate along its cutting direction.

[0043] In a third aspect, a battery cell is provided, which is wound by the winding method described above; or, is prepared by the winding equipment described above.

[0044] In a third aspect, a battery is provided, comprising a shell, and a battery cell located in the shell.

[0045] In a fourth aspect, an electrical device is provided, comprising the battery.

[0046] The beneficial effects of the present invention are to provide a winding method, a winding device, a battery cell, a battery and an electrical device:

[0047] Firstly, the first diaphragm, the first pole piece and the second diaphragm are fed in synchronously and start to be wound, thereby solving the problem of low production efficiency caused by step-by-step feeding in the prior art;

[0048] Secondly, after the diaphragm and the tape are cut, the first diaphragm and the second diaphragm are connected by the tape and the end face of the first pole piece is wrapped. On the one hand, after the end face of the first pole piece is wrapped, the active material at the end face of the first pole piece can be prevented from being scattered everywhere. On the other hand, the tape is also provided between the end position of the first pole piece and the diaphragm, thereby reducing the risk of the metal burrs at the end face of the first pole piece directly piercing the diaphragm; thereby, the problem that the first pole piece is easy to shed powder and pierce the diaphragm in the prior art can be solved;

[0049] Furthermore, since the first diaphragm and the second diaphragm are connected by tape and wrap the end surface of the first pole piece, the first pole piece cannot be offset in the width direction relative to the first diaphragm and the second diaphragm, thereby solving the problem of the first pole piece being easily offset in the prior art.

[0050] Therefore, the winding method, winding equipment, battery cell, battery and electrical device provided by the present invention can effectively solve the problems of low production efficiency of existing winding methods, easy powder loss and puncture of the diaphragm, and easy tail deviation of the pole piece. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0052] Figure 1 A flowchart of a winding method provided in an embodiment;

[0053] Figure 2 A schematic diagram of the process of cutting and gluing a continuous sheet provided in the embodiment;

[0054] Figure 3 A schematic diagram of the structure of a winding device provided in an embodiment;

[0055] Figure 4 A schematic diagram of the state change of the battery cell before and after hot cutting by the second cutting mechanism provided in the embodiment;

[0056] Figure 5 A schematic diagram of a battery cell structure provided in an embodiment;

[0057] Figure 6 This is a schematic diagram of a thicker blank area of ​​a connecting substrate provided in an embodiment.

[0058] In the figure:

[0059] 1. Continuous sheet; 1a. Front pole piece; 1b. Back pole piece;

[0060] 2. Adhesive tape; 201. Adhesive part; 202. Connecting substrate; 2021. Blank area; 2a. Connector;

[0061] 3. The first diaphragm;

[0062] 4. Second diaphragm;

[0063] 5. The second pole piece;

[0064] 6. Cutting and pasting mechanism; 601. Pole piece clamping and fixing mechanism; 602. First cutting mechanism; 603. First connecting mechanism;

[0065] 7. Winding mechanism; 701. First unwinding mechanism; 702. Second unwinding mechanism; 703. Third unwinding mechanism; 704. Fourth unwinding mechanism; 705. Rewinding mechanism; 7051. Rotating plate; 7052. First winding needle; 7053. Second winding needle; 706. Third cutting mechanism;

[0066] 8. Second cutting mechanism; 801. Hot pressing plate; 802. Hot cutting knife. DETAILED DESCRIPTION

[0067] In the present invention, terms such as "first" and "second" are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship of quantity, priority or sequence between these entities or operations.

[0068] Unless otherwise expressly specified or limited, in the description of the embodiments of the present invention, the terms "install", "connect", "connect", "fix", "set" and the like used should be understood in a broad sense. For example, the "connection" can be a fixed connection, a detachable connection, or an integrated setting; it can be a mechanical connection, an electrical connection, or a communication connection; it can be a direct connection, or an indirect connection through an intermediate medium; it can be the internal connection of two elements or the interaction relationship between two elements. For those skilled in the art of the technical field to which the present invention belongs, the specific meanings of the above terms in the embodiments of the present invention can be understood according to the specific circumstances.

[0069] The present invention provides a winding method, a winding device, a battery cell, a battery and an electrical device, which are suitable for the application scenario of winding a first diaphragm, a first pole piece, a second diaphragm and a second pole piece into a battery cell. The present invention can effectively solve the problems of low production efficiency of the existing winding method, easy powder loss and puncture of the diaphragm by the pole piece, and easy tail deviation of the pole piece.

[0070] Example 1

[0071] This embodiment provides a winding method, which is performed by the winding device provided in Embodiment 2, and is used to wind the first diaphragm 3, the first pole piece, the second diaphragm 4, and the second pole piece 5 into the battery cell in Embodiment 3.

[0072] See also Figure 1 The winding method provided in this embodiment includes the following steps S10-S30:

[0073] S10: Cut the continuous sheet 1 and then connect them with the adhesive tape 2 to obtain a first electrode sheet;

[0074] In this embodiment, the electrode sheet is in a continuous state when it is received. After being cut, it is wound. For the sake of distinction, the continuous whole before cutting will be referred to as "continuous sheet 1", the two broken parts after cutting according to the preset length will be referred to as "cut electrode segments", and the whole obtained by connecting the two cut electrode segments with tape 2 will be referred to as "first electrode sheet".

[0075] One of the cut pole pieces is the front pole piece 1a which is being wound, and the other cut pole piece is the rear pole piece 1b which is being unwound.

[0076] In some of these embodiments, see Figure 2 , the step S10 comprises:

[0077] S101: cutting the continuous sheet 1 to form two independent post-cutting electrode segments;

[0078] S102: pulling the two cut pole segments apart to a preset distance;

[0079] S103: connecting the two cut electrode segments by using the adhesive tape 2.

[0080] In this embodiment, the two cut electrode segments are spaced apart, that is, they are spaced apart by a preset distance and then connected by the adhesive tape 2. In other words, the adhesive tape 2 starts from the end position of one of the cut electrode segments, crosses the space between the two cut electrode segments, and is connected to the end position of the other cut electrode segment.

[0081] For the convenience of description, the positions where the tape 2 and the cut pole segments are attached (i.e., the two ends of the tape 2) are referred to as "sticking areas", and the middle position where the tape 2 spans the spacing between the two cut pole segments is referred to as "blank area 2021". It can be understood that the blank area 2021 is located between the two cut pole segments, so that the cut pole segments will not be cut when the blank area 2021 is cut later.

[0082] In this embodiment, the adhesive tape 2 includes two adhesive portions 201 spaced apart and a connecting substrate 202 connecting the two adhesive portions 201. That is, the two ends of the connecting substrate 202 are the adhesive regions, and the adhesive regions at both ends of the connecting substrate 202 are provided with the adhesive portions 201 so as to be bonded to the corresponding cut electrode segments through the adhesive portions 201. The middle position of the connecting substrate 202 is the blank region 2021, and the blank region 2021 has no adhesive.

[0083] In some embodiments, the adhesive tape 2 may be provided as a prefabricated part. In this case, step S103 includes:

[0084] The adhesive portion 201 at one end of the adhesive tape 2 is adhered to one of the cut electrode segments, and the adhesive portion 201 at the other end of the adhesive tape 2 is adhered to the other cut electrode segment.

[0085] It should be noted that the tape 2 is set as a prefabricated part, and a large amount of tape 2 is prepared in advance. During subsequent production, the prefabricated tape 2 can be directly pasted and fixed to the two cut electrode segments after the distance is pulled apart. This is simple and quick, and has high production efficiency.

[0086] In some embodiments, the adhesive portion 201 and the connecting substrate 202 may also be fixed on site during the winding process. In this case, step S103 includes:

[0087] ① The adhesive part 201 is arranged at the end positions of the two cut electrode segments respectively (either by attaching adhesive or coating with glue);

[0088] ② Paste one end of the connecting substrate 202 onto the adhesive portion 201 of one of the cut electrode segments, and paste the other end of the connecting substrate 202 onto the adhesive portion 201 of another of the cut electrode segments.

[0089] It should be noted that the production method of first laying the adhesive portion 201 at the end position of the cut electrode segment and then sticking the connecting substrate 202 on does not require the advance preparation of the prefabricated tape 2. During the production process, the length of the blank area 2021 can be flexibly adjusted according to production needs, which greatly reduces the inventory pressure of prefabricated parts.

[0090] In this embodiment, since a layer of diaphragm is provided on each side of the electrode segment after cutting, an adhesive tape 2 can be provided on each side of the upper and lower sides of the end position of the electrode segment after cutting, and in this case, two adhesive tapes 2 are provided between the two diaphragms. Of course, in some other embodiments, only one adhesive tape 2 can be provided on the upper or lower side of the end position of the electrode segment after cutting, and in this case, one adhesive tape 2 is provided between the two diaphragms.

[0091] S20: Winding the first diaphragm 3, the first pole piece, the second diaphragm 4, and the second pole piece 5, so that the first diaphragm 3, the wound pole piece (i.e., the front pole piece 1a), and the second diaphragm 4 wrap the second pole piece 5;

[0092] See also Figure 3 In this embodiment, step S20 includes:

[0093] S201: Pre-roll the first diaphragm 3, the first electrode piece (i.e., the two electrode pieces after cutting connected by the tape 2), and the second diaphragm 4 to a preset length (e.g., 3-10 mm);

[0094] S202: inserting the second pole piece 5 for winding;

[0095] S203: cutting the second pole piece 5;

[0096] S204 : the first diaphragm 3 , the first pole piece, and the second diaphragm 4 are continuously wound for several turns (eg, half a turn) to wrap the second pole piece 5 .

[0097] The winding start end of the second pole piece 5 is slightly shorter than the winding start end of the pole segment after cutting to ensure that the two meet the Overhang requirement in the length direction to prevent lithium deposition in the battery cell. Furthermore, the distance difference between the winding start end of the pole segment after cutting and the winding start end of the second pole piece 5 is 3-10mm. Setting the distance difference within this range can ensure both the energy density of the battery cell and the Overhang requirement. The winding end of the first diaphragm 3, the winding end of the pole segment after cutting and the winding end of the second diaphragm 4 are aligned, and the winding end of the pole segment after cutting exceeds the winding end of the second pole piece 5 by half a circle. Such a design is also to ensure the Overhang requirement between the pole segment after cutting and the second pole piece 5.

[0098] The end of the electrode segment after cutting is attached with an adhesive tape 2 extending outward, and the adhesive tape 2 extending outward forms the winding start end and the winding end end of the electrode segment after cutting.

[0099] In S20 , the first diaphragm 3 , the first pole piece, and the second diaphragm 4 are fed in synchronously and start to be wound, thereby solving the problem of low production efficiency caused by step-by-step feeding in the prior art.

[0100] In this embodiment, the first electrode piece is an anode piece, and the second electrode piece 5 is a cathode piece.

[0101] In other embodiments, the first pole piece can also be set as the cathode piece, and the second pole piece 5 can be set as the anode piece. That is, the tape 2 is set at the cathode piece, so that the second diaphragm 4, the tape 2 and the first diaphragm 3 are hot-melted and fused to wrap the end face of the cathode piece. At this time, in order to prevent lithium deposition in the battery cell, the outermost circle of the battery cell needs to be the anode piece. Therefore, the length of the tape 2 connected to the cathode piece needs to be greater than the length of the anode piece of the outermost circle, which will increase the difficulty of connecting the two cathode pieces using the tape 2 to a certain extent. In addition, the anode piece is softer than the cathode piece, and it is more likely to swing when the pole piece is cut. Therefore, it is more practical to solve the problem of the anode piece swinging. Therefore, a better solution is that the first pole piece is the anode piece and the second pole piece 5 is the cathode piece.

[0102] Of course, the tape 2 can also be attached to both the anode sheet and the cathode sheet, which can solve the problems of low production efficiency, easy powder loss and puncture of the diaphragm, and easy tail deviation of the anode sheet and the cathode sheet at the same time.

[0103] S30: Perform a fusing process at the position between the two cut electrode segments, so that the first diaphragm, the tape 2, and the second diaphragm 4 after the fusing are fused and connected at the fusing position; at this time, the ends of the two cut electrode segments close to each other are covered by the first diaphragm 3, the tape 2, and the second diaphragm 4 after the fusing.

[0104] In this embodiment, step S30 not only requires cutting the first diaphragm 3, the tape 2, and the second diaphragm 4, but also requires connecting the first diaphragm 3 and the second diaphragm 4 via the tape 2 so as to wrap the end surface of the cut electrode segment.

[0105] See also Figure 4 After cutting the first diaphragm 3, the tape 2, and the second diaphragm 4, the tape 2 will be divided into two to form two connectors 2a, each connector 2a corresponding to an end face of a cut pole piece (one connector 2a protrudes backward from the end face of the front pole piece 1a, and the other connector 2a protrudes forward from the starting end face of the rear pole piece 1b).

[0106] In this embodiment, the step of performing a fusing process at a position between the two trimmed electrode segments includes:

[0107] First, the middle position of the tape 2 (i.e., the blank area 2021) is subjected to heat pressing for a relatively long time. Specifically, the length of the heat pressing time is controlled to be sufficient to allow the first diaphragm 3 and the second diaphragm 4 to be heat-melted through the blank area 2021; the first diaphragm 3 and the second diaphragm 4 after heat-melting form a bag, thereby wrapping the end surface of the cut electrode segment;

[0108] Then, a hot cutter is used to cut the blank area 2021 , and the first diaphragm 3 , the adhesive tape 2 , and the second diaphragm 4 are cut simultaneously.

[0109] It should be noted that cold cutting may cause stress on the material, resulting in edge cracks, affecting the integrity and performance of the product. Therefore, after the hot pressing step is completed, although the first diaphragm and the second diaphragm have been hot-melted and fused through the blank area to form a bag to wrap the end face of the cut electrode segment, hot cutting is still performed. Hot cutting can provide more precise and neat cutting effects, while reducing the risk of material tearing and ensuring the sealing of the cutting edge, thereby ensuring the stability of the internal structure of the battery and long-term reliability.

[0110] In another embodiment, the step of performing a fusing process at a position between the two trimmed electrode segments includes:

[0111] First, the middle position of the adhesive tape 2 is subjected to short-term hot pressing, so that the first diaphragm 3 and the second diaphragm 4 are pre-connected through the middle position of the adhesive tape 2; it should be noted that due to the short hot pressing time, it is not enough to allow the first diaphragm 3, the second diaphragm 4 and the adhesive tape 2 to be fully and fully melted, and the three are only heated on the surface and are not fully hot-pressed;

[0112] Then, hot cutting is performed at the middle position of the tape 2, so that the first diaphragm 3 and the second diaphragm 4 are hot-melted and fused through the middle position of the tape 2 and wrap the end surfaces of the two cut electrode segments that are close to each other, while the first diaphragm 3, the tape 2, and the second diaphragm 4 are cut simultaneously.

[0113] Performing hot pressing pre-connection first can reduce the gap between the diaphragm and the connection substrate 202, thereby shortening the moving distance of the diaphragm and the connection substrate 202, which is beneficial to improving the hot melt fusion effect of the diaphragm and the connection substrate 202.

[0114] In another embodiment, the step of performing a fusing process at a position between the two trimmed electrode segments comprises:

[0115] The middle position of the adhesive tape 2 is heat-cut, so that the first diaphragm 3 and the second diaphragm 4 are heat-melted through the middle position of the adhesive tape 2, and the first diaphragm 3, the adhesive tape 2, and the second diaphragm 4 are cut simultaneously.

[0116] Directly using the hot cutter 802 can simultaneously perform heat-melting fusion of the first diaphragm 3 , the second diaphragm 4 and the blank area 2021 , and at the same time cut the first diaphragm 3 , the tape 2 , and the second diaphragm 4 .

[0117] Hot cutting with a hot cutter can reduce cutting resistance, improve the cutting efficiency of the hot cutter, further simplify the production process and improve production efficiency.

[0118] It should be noted that the "hot melt fusion" in this embodiment is not a simple bonding, but a mutual fusion of the substrate 202 and the diaphragm, and the two are in a state of mutual fusion. Simple bonding is only a physical connection, and the connection effect is poor. The battery cells made in this way are easily affected by the operating conditions during use, such as bumps and impacts, which can easily lead to connection failure, and then cause the diaphragm and the pole piece to shift, causing short circuit and lithium precipitation risks. The hot melt fusion of the present invention belongs to the fusion of materials at the microscopic level, and the connection effect is stronger. The battery cells made by the technical solution of the present invention can ensure the bonding strength of the diaphragm and the pole piece even under harsh conditions, avoid connection failure, and improve the safety performance of the battery cells.

[0119] Hot melt fusion specifically refers to the first diaphragm 3, the tape 2, and the second diaphragm 4 being melted by heat and then recombined to form a whole, that is:

[0120] Before fusion: the thickness of the first diaphragm 3 is D1, the thickness of the second diaphragm 4 is D2, and the thickness of the tape 2 at the cutting position is D3;

[0121] After fusion:

[0122] At the cutting position, the total thickness of the first diaphragm 3, the second diaphragm 4 and the tape 2 at the cutting position is T < (D1+D2+D3);

[0123] At the non-cutting position, the total thickness T of the first diaphragm 3 , the second diaphragm 4 and the tape 2 at the cutting position is (D1+D2+D3).

[0124] It can be understood that, on the one hand, after the first diaphragm 3 and the second diaphragm 4 are connected by the tape 2 and wrap the end surface of the electrode segment after cutting, the active material at the end surface of the electrode segment after cutting can be prevented from scattering everywhere.

[0125] On the other hand, an adhesive tape 2 is provided between the end of the electrode segment after cutting and the diaphragm, and the adhesive tape 2 can prevent the metal burrs from directly contacting the diaphragm, thereby reducing the risk of the metal burrs at the end surface of the electrode segment after cutting directly piercing the diaphragm; thereby, the problem of easy powder loss and piercing of the diaphragm by the electrode segment after cutting in the prior art can be solved;

[0126] Furthermore, since the first diaphragm 3 and the second diaphragm 4 are fused and connected by the tape 2 and wrap the end face of the cut pole segment, the cut pole segment cannot be offset in the width direction relative to the first diaphragm 3 and the second diaphragm 4, thereby solving the problem of easy tail-swinging and offset of the cut pole segment in the prior art.

[0127] In some embodiments, the material of the first diaphragm 3 and / or the second diaphragm 4 is the same as that of the connection substrate 202 , so as to improve the connection reliability when the diaphragm and the connection substrate 202 are connected by thermal compression.

[0128] In this embodiment, since the connection substrate 202 only needs to be provided with adhesive portions 201 at both ends, and the middle position is left blank, no matter whether a conventional cutter is used to cut in the blank area 2021 or a hot cutter 802 is used to cut in the blank area 2021, adhesive will not stick to the cutter, which is conducive to extending the service life of the cutter. Of course, in some other embodiments, adhesive can also be provided in the blank area 2021, and the present invention is not limited to this.

[0129] In summary, the winding method provided in this embodiment has the following advantages:

[0130] (1) The first diaphragm 3, the first electrode piece, and the second diaphragm 4 are fed in synchronously and start winding, which solves the problem of low production efficiency caused by step-by-step feeding in the prior art;

[0131] (2) The first diaphragm 3 and the second diaphragm 4 are fused and connected by the connecting body 2a formed by cutting the adhesive tape 2, and the end surface of the electrode segment after cutting is wrapped. On the one hand, the active material at the end surface of the electrode segment after cutting can be prevented from being scattered everywhere, and on the other hand, the electrode segment after cutting cannot be offset in the width direction relative to the first diaphragm 3 and the second diaphragm 4;

[0132] (3) An adhesive tape 2 is provided between the end of the electrode segment after cutting and the diaphragm to prevent the metal burrs from directly contacting the diaphragm and reduce the risk of the metal burrs at the end surface of the electrode segment after cutting directly piercing the diaphragm;

[0133] (4) To connect the substrate 202, only the adhesive portions 201 need to be provided at both ends, and a blank space is left in the middle. Whether a conventional cutter or a hot cutter 802 is used to cut in the blank area 2021, the adhesive will not stick to the cutter, thereby extending the service life of the cutter.

[0134] (5) Use a connection substrate 202 made of the same material as the diaphragm to improve the reliability during thermal compression bonding.

[0135] Example 2

[0136] This embodiment provides a winding device, which is used to produce the battery cell provided in Embodiment 3 by the winding method provided in Embodiment 1.

[0137] See also Figure 3 The winding device provided in this embodiment includes a cutting and pasting mechanism 6, a winding mechanism 7, and a second cutting mechanism 8.

[0138] The cutting and pasting mechanism 6 is used to cut the continuous sheet 1 into two cut electrode segments, and connect the two spaced cut electrode segments through the tape 2. The winding mechanism 7 is used to wind the first diaphragm 3, the first electrode piece, the second diaphragm 4, and the second electrode piece 5, so that the first diaphragm 3, the first electrode piece, and the second diaphragm 4 cover the second electrode piece 5. The second cutting mechanism 8 is used to perform a fusing process at the position between the two cut electrode segments of the first electrode piece, so that the first diaphragm 3, the tape 2, and the second diaphragm 4 after the fusing are fused and connected at the fusing position, and at this time, the ends of the two cut electrode segments close to each other are covered by the first diaphragm 3, the tape 2, and the second diaphragm 4 after the fusing.

[0139] In this embodiment, the winding mechanism 7 includes a first unwinding mechanism 701 for releasing the first diaphragm 3, a second unwinding mechanism 702 for releasing the first pole piece, a third unwinding mechanism 703 for releasing the second diaphragm 4, a fourth unwinding mechanism 704 for releasing the second pole piece 5, a winding mechanism 705 for winding up the first diaphragm 3, the first pole piece, the second diaphragm 4 and the second pole piece 5, and a third cutting mechanism 706 for cutting off the second pole piece 5.

[0140] The cutting and pasting mechanism 6 includes two spaced-apart electrode clamping and fixing mechanisms 601 , a first cutting mechanism 602 for cutting the continuous sheet 1 into two cut electrode segments, and a first connecting mechanism 603 for pasting the adhesive tape 2 to the two cut electrode segments.

[0141] After the pole piece clamping and fixing mechanism 601 clamps and fixes the cut pole piece, the first cutting mechanism 602 can cut the continuous sheet 1 into two cut pole pieces.

[0142] Further, regarding the first connecting mechanism 603:

[0143] In some of the embodiments, when the adhesive tape 2 is a preform, the first connecting mechanism 603 is a robot that can grab the transfer adhesive tape 2;

[0144] In some of the embodiments, when it is necessary to fix the adhesive portion 201 and the connecting substrate 202 on site during the winding process, the first connecting mechanism 603 includes an adhesive pasting device or a glue coating device for fixing the adhesive portion 201 (the adhesive portion 201 is an adhesive or a glue coating) on ​​the cut electrode segment, and a robot for mounting the connecting substrate 202 to the two adhesive portions 201.

[0145] In this embodiment, regarding the second cutting mechanism 8:

[0146] In some embodiments, when hot pressing before cutting is required, the second cutting mechanism 8 includes two oppositely arranged hot pressing plates 801 and a hot cutting knife 802 for cutting the adhesive tape 2 and the diaphragm.

[0147] First, use two relatively arranged hot pressing plates 801 to hot press the first diaphragm 3, the blank area 2021 of the tape 2, and the second diaphragm 4 (the hot pressing temperature of the hot pressing plate 801 is 70℃-110℃), so that the first diaphragm 3, the blank area 2021 of the tape 2, and the second diaphragm 4 are hot-melted or pre-connected; then use a hot cutting knife 802 (the hot cutting knife 802 can instantly reach 130℃-300℃ when cutting) to cut.

[0148] The hot pressing plate 801 acts on the entire connecting substrate 202, which can make the blank area 2021 of the entire connecting substrate 202 and the diaphragm fit tightly, increase the connection and fixing area between the connecting substrate 202 and the diaphragm, and further increase the connection reliability between the electrode segment and the diaphragm after cutting, ensure that the winding starting end of the electrode segment and the winding starting end of the diaphragm after cutting are fully combined together, and the winding end of the electrode segment and the winding end of the diaphragm after cutting are also fully combined together, avoiding the end of the electrode segment and the end of the diaphragm after cutting being in a free end state without mutual constraint and positioning, resulting in head and tail swinging.

[0149] Furthermore, in order to improve the structural compactness of the second cutting mechanism 8, a receiving groove sufficient to accommodate the hot cutter 802 can be set in the middle position of one of the hot pressing plates 801, and the hot cutter 802 can be installed in the receiving groove. When hot pressing is required, the hot cutter 802 is completely received in the receiving groove so that the two hot pressing plates 801 can fit as closely as possible to complete the hot pressing. After the hot pressing is completed, the two hot pressing plates 801 are not separated first, but the hot cutter 802 is driven to extend out of the receiving groove by a linear module such as a cylinder or a motor screw so as to cut the diaphragm and the tape 2.

[0150] Regarding the temperature of the hot cutter 802, if the temperature of the hot cutter 802 is too high, the tape 2 and the diaphragm may shrink at the cutting point and cannot be hot-melt-fused. If the temperature of the hot cutter 802 is too low, the tape 2 and the diaphragm cannot reach the hot-melt-fused temperature and cannot be hot-melt-fused. Therefore, the temperature of the hot cutter 802 needs to be set within an appropriate range. The hot cutting temperature of the hot cutter of the present invention is 130℃-300℃.

[0151] On the basis of ensuring the realization of hot melt fusion, in order to further ensure the hot melt fusion effect of the tape and the diaphragm, after the unremitting efforts of the inventors, the inventors found that the hot melt fusion connection effect of the tape and the diaphragm is best when the cutter temperature is set at 180℃-240℃, and the diaphragm types applicable to this temperature range are also the widest, and this temperature range is applicable to many common diaphragm types on the market: such as PP diaphragms, PE diaphragms, etc. Specifically, the cutter temperature can be 180℃, 185℃, 190℃, 195℃, 200℃, 205℃, 210℃, 215℃, 220℃, 225℃, 230℃, 235℃ or 240℃, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0152] In some embodiments, when cutting is required at the same time as hot pressing, the second cutting mechanism 8 may also be provided with only a hot cutting knife 802, eliminating the two hot pressing plates 801. The hot cutting knife 802 directly hot-cuts the first diaphragm 3, the blank area 2021 of the tape 2, and the second diaphragm 4, thereby achieving cutting at the same time as hot melting and fusion.

[0153] Further, the specific operation method of pulling the two cut pole pieces apart to a preset distance is described as follows: After the first cutting mechanism 602 cuts the continuous sheet 1 into the front pole piece 1a and the rear pole piece 1b, the rear pole piece 1b will stop feeding forward, and the winding mechanism 705 can continue to wind up the front pole piece 1a, so that the front pole piece 1a continues to move forward so as to be pulled apart from the rear cut pole piece to a preset distance. Then, the front pole piece 1a and the rear pole piece 1b are connected by the tape 2. At this time, the winding mechanism 705 continues to wind up the front pole piece 1a, and the rear pole piece 1b can be driven by the tape 2 to continue to be conveyed forward.

[0154] The winding mechanism 705 provided in this embodiment includes a rotating disk 7051, and a first winding needle 7052 and a second winding needle 7053 installed on the rotating disk 7051. The winding process of the winding mechanism 705 is as follows:

[0155] ① The winding starting ends of the second diaphragm 4, the first pole piece, and the first diaphragm 3 are aligned and synchronously fed into the first winding needle 7052, the winding starting end of the second pole piece 5 is inserted into the first winding needle 7052, and a distance of 3-10 mm is maintained from the head of the cut pole piece. The first winding needle 7052 (located at the first station at this time) clamps the first diaphragm 3, the first pole piece, the second diaphragm 4, and the second pole piece 5 and winds them together. After winding to a specified length, the third cutting mechanism 706 cuts the second pole piece 5;

[0156] ② Then, the turntable 7051 rotates, so that the first winding needle 7052 drives the battery cell to rotate to the second station, and at the same time, the second winding needle 7053 originally located at the second station rotates to the first station;

[0157] ③ When the first winding needle 7052 drives the battery cell to rotate to the second station, the hot cutting knife 802 of the second cutting mechanism 8 extends to cut the first diaphragm 3, the tape 2 and the second diaphragm 4 at the same time, and after cutting, the winding end of the electrode segment after cutting of the previous battery cell and the winding start end of the electrode segment after cutting of the next battery cell are formed;

[0158] More specifically, the hot cutter 802 cuts the tape into a first connector 2a and a second connector 2a. The second connector 2a is bonded to the tail of the electrode segment after cutting of the previous battery cell, and the first connector 2a is bonded to the head of the electrode segment after cutting of the next battery cell. Since the hot cutter 802 instantly reaches a temperature of 130-300°C during cutting, the tape and the separator are successfully cut and hot-melted together, and the first winding needle 7052 begins to rotate to finish and complete the battery cell unloading;

[0159] ④ While the first winding needle 7052 is performing the above operation, the cutting and pasting mechanism 6 completes the gluing, the second pole piece 5 is inserted, the second winding needle 7053 clamps the second diaphragm 4, the first pole piece, the first diaphragm 3 and the second pole piece 5, and repeats the winding operation of the first winding needle 7052. This cycle is repeated to achieve non-stop winding operation.

[0160] When the cathode sheet is connected by tape 2 (i.e. the cathode sheet is cut into cathode sheets), the equipment does not need to be replaced. Since the outermost circle must be the anode sheet (to prevent lithium deposition), the length of the cathode sheet must be greater than the length of the outermost anode sheet when the cathode sheet is cut and glued.

[0161] The winding device provided in this embodiment has at least the following advantages:

[0162] ① Using hot pressing and hot cutting technology to achieve effective fusion between the diaphragm and the electrode, enhancing the safety and reliability of the product and reducing the risk of short circuit and lithium deposition caused by connection failure during use;

[0163] ②Through the design of double winding needles alternating operation, continuous winding without stopping is achieved, greatly improving production efficiency;

[0164] ③ By providing a receiving groove in the middle of the hot pressing plate 801 to install the hot cutting knife 802, the compactness of the structure of the second cutting mechanism 8 is improved and space is saved;

[0165] ④ By optimizing the temperature setting of the hot cutter 802, the hot melt fusion effect of the tape and the diaphragm is ensured. At the same time, it is applicable to various types of diaphragms, thereby improving the versatility of the equipment.

[0166] The specific working process and beneficial effects of the winding equipment provided in this embodiment have been described in detail in Example 1. On the basis of Example 1, the features not explained in this embodiment adopt the explanation in Example 1 and have the same beneficial effects, and will not be repeated here.

[0167] Example 3

[0168] This embodiment provides a battery cell, a battery and an electrical device, wherein the battery cell is produced by the winding equipment provided in Embodiment 2 through the winding method provided in Embodiment 1.

[0169] The battery comprises a shell and a cell in the shell. The power-consuming device comprises a power-consuming mechanism and a power supply mechanism for supplying power to the power-consuming mechanism; wherein the power supply mechanism comprises the cell or the battery.

[0170] The following is an introduction to the specific structure of the battery cell.

[0171] See also Figure 5 The battery cell provided in this embodiment includes a first diaphragm 3, a first pole piece, a second diaphragm 4, and a second pole piece 5 in sequence; wherein at least one end of the first diaphragm 3 and the second diaphragm 4 are fused and connected by a connector 2a, which wraps the end face of the first pole piece and limits the deviation of the wrapped end of the first pole piece relative to the two diaphragms.

[0172] It should be noted that, since the winding process is a continuous process, when describing the winding process, the first diaphragm 3, the second diaphragm 4 and the second pole piece 5 refer to continuous sheets in a continuous state, and the first pole piece refers to the whole obtained by connecting two cut pole pieces. Each battery cell is formed by winding and cutting the continuous first diaphragm 3, the first pole piece, the second diaphragm 4, and the second pole piece 5. In other words, each battery cell is composed of a section of the first diaphragm 3, a section of the first pole piece, a section of the second diaphragm 4 and a section of the second pole piece. For ease of understanding, this solution is also named "the first diaphragm 3, the first pole piece, the second diaphragm 4, and the second pole piece 5" when describing the battery cell structure.

[0173] It can be understood that the continuous first pole piece may include N (N is greater than 2) cut pole segments, and N battery cells can be continuously produced. Among them, in the continuous first pole piece, two adjacent cut pole segments are connected by tape 2, the first cut pole segment is only connected to tape 2 at the end of winding, the last cut pole segment is only connected to tape 2 at the starting end of winding, and the remaining cut pole segments are connected to tape 2 at the starting end and the end of winding. Correspondingly, the first battery cell produced is only fused and connected by connector 2a at the end of winding of the first separator 3 and the second separator 4, and the last battery cell produced is only fused and connected by connector 2a at the starting end of winding of the first separator 3 and the second separator 4, and the first separator 3 and the second separator 4 of the remaining battery cells are fused and connected by corresponding connector 2a at the starting end and the end of winding.

[0174] The beneficial effects of the battery cell provided in this embodiment can be referred to the description in Embodiments 1-2, which will not be repeated here.

[0175] In some embodiments, the connector 2a includes an adhesive portion 201 and a connecting substrate 202. The adhesive portion 201 is bonded to the first pole piece; one end of the connecting substrate 202 is bonded to the adhesive portion 201, and the other end extends to the outside of the end surface of the first pole piece to connect the first diaphragm 3 and the second diaphragm 4.

[0176] Specifically, the connecting substrate 202, the first diaphragm 3, and the second diaphragm 4 are fused and connected, for example, by heat cutting, heat melting, ultrasonic heat melting, etc., which is not limited in this embodiment.

[0177] Furthermore, the length dimensions of the first diaphragm 3 and the second diaphragm 4 are equal, and the length dimensions of the two are greater than the length dimension of the first pole piece, so that the ends of the first diaphragm 3 and the second diaphragm 4 extend to the outside of the end surface of the first pole piece; wherein the portions of the first diaphragm 3 and the second diaphragm 4 extending to the outside of the end surface of the first pole piece are thermally melted with the connecting substrate 202.

[0178] In this embodiment, the material of the first diaphragm 3 and / or the second diaphragm 4 is the same as the connecting substrate 202. For example, the diaphragm material is PP, and the connecting substrate 202 is also PP. It is easier to perform hot melt fusion of the same material, and the connection reliability is better. Especially when the blank area 2021 is not provided with adhesive, the object cut by the hot cutter 802 is the connecting substrate 202 and the diaphragm of the same material, which can minimize the impact of heat shrinkage at the cutting point of the connecting substrate 202 and the diaphragm on hot melt fusion, and avoid the difficulty of hot melt fusion of different materials.

[0179] The connector 2 a is adhered and fixed to a surface of the first pole piece close to the first diaphragm 3 and / or a surface of the first pole piece close to the second diaphragm 4 .

[0180] Since a layer of diaphragm is provided on each side of the first pole piece, a connector 2a may be provided on each side of the upper and lower sides of the end of the first pole piece, and in this case, two connectors 2a are provided between the two diaphragms. Of course, in some other embodiments, only one connector 2a may be provided on the upper or lower side of the first pole piece, and in this case, one connector 2a is provided between the two diaphragms.

[0181] In some other embodiments, glue may also be provided at both ends of the connecting substrate 202 close to the second diaphragm 4 or the first diaphragm 3 (the middle position is still left blank to avoid affecting the service life of the hot cutting knife 802 later), that is, before hot pressing and cutting, the connecting substrate 202 is not only bonded to the first pole piece, but also bonded to the corresponding diaphragms. With this arrangement, the tape 2 and the diaphragm can be pre-bonded together, which is conducive to the realization of one-size-fits-all cutting.

[0182] In this embodiment, see Figure 6 , the thickness of the connection area at both ends of the connection substrate 202 is thinner, and the thickness of the blank area 2021 in the middle is thicker, that is, the connection substrate 202 as a whole presents a convex structure. Since the blank area 2021 is the main hot melt fusion area, thickening the blank area 2021 can increase the amount of the connection substrate 202 involved in hot melt fusion, thereby improving the reliability of hot melt fusion. Of course, in some embodiments, for the convenience of processing, the connection substrate 202 can also be set to Figure 2 Shown is a straight structure with uniform thickness throughout.

[0183] Furthermore, when the blank area 2021 in the middle of the connecting substrate 202 is thick, the adhesive tape 2 can be provided only on one side of the cut electrode segment. Because the thick blank area 2021 can contact the second diaphragm 4 and the first diaphragm 3 on both sides, thereby achieving reliable hot melt fusion between the second diaphragm 4, the first diaphragm 3 and the connecting substrate 202.

[0184] The specific manufacturing process of the battery cell provided in this embodiment has been described in detail in Embodiment 1 and Embodiment 2. Based on Embodiment 1, the features not explained in this embodiment adopt the explanation in Embodiment 1 and have the same beneficial effects, and will not be repeated here.

[0185] Finally, it should be noted that although the above embodiments have been described in the specification and drawings of this application, this does not limit the scope of patent protection of this application. All technical solutions generated by replacing or modifying equivalent structures or equivalent processes based on the essential concept of this application using the contents recorded in the specification and drawings of this application, as well as directly or indirectly implementing the technical solutions of the above embodiments in other related technical fields, are included in the scope of patent protection of this application.

Claims

1. A winding method, characterized in that: include: Winding a first diaphragm (3), a first pole piece, a second diaphragm (4), and a second pole piece (5); wherein the first pole piece comprises two spaced-apart cut pole segments, and an adhesive tape (2) connecting the two cut pole segments; After the winding is completed, the stacked first diaphragm (3), the adhesive tape (2), and the second diaphragm (4) are simultaneously subjected to a fusing process, so that the first diaphragm (3), the adhesive tape (2), and the second diaphragm (4) are fused and connected at the fusing point.

2. The winding method according to claim 1, characterized in that: The stacked first diaphragm (3), the adhesive tape (2), and the second diaphragm (4) are simultaneously subjected to a fusing process, comprising: The middle position of the adhesive tape (2) is heat-cut, so that the first diaphragm (3) and the second diaphragm (4) are fused and connected through the middle position of the adhesive tape (2), and the first diaphragm (3), the adhesive tape (2), and the second diaphragm (4) are cut simultaneously.

3. The winding method according to claim 2, characterized in that: Before hot cutting the middle position of the adhesive tape (2), the middle position of the adhesive tape (2) is first hot pressed, so that the first diaphragm (3) and the second diaphragm (4) are pre-connected through the middle position of the adhesive tape (2).

4. The winding method according to claim 1, characterized in that: The stacked first diaphragm (3), the adhesive tape (2), and the second diaphragm (4) are subjected to a fusing process, comprising: First, the middle position of the adhesive tape (2) is subjected to heat pressing, so that the first diaphragm (3) and the second diaphragm (4) are fused and connected through the middle position of the adhesive tape (2); Then, hot cutting is performed at the middle position of the adhesive tape (2), and the first diaphragm (3), the adhesive tape (2), and the second diaphragm (4) are cut simultaneously.

5. The winding method according to any one of claims 2 to 4, characterized in that: Before fusion: the thickness of the first diaphragm (3) is D1, the thickness of the second diaphragm (4) is D2, and the thickness of the adhesive tape (2) is D3; After fusion: At the cutting position, the total thickness of the first diaphragm (3), the second diaphragm (4) and the adhesive tape (2) is T<(D1+D2+D3); At the non-cutting position, the total thickness T of the first diaphragm (3), the second diaphragm (4) and the adhesive tape (2) is (D1+D2+D3).

6. The winding method according to claim 1, characterized in that: The first diaphragm (3), the first pole piece, the second diaphragm (4), and the second pole piece (5) are wound, comprising: Firstly, the winding start ends of the first diaphragm (3), the first pole piece, and the second diaphragm (4) are aligned, and then pre-rolled to a preset length; Inserting the second pole piece (5) for winding; Synchronously winding the first diaphragm (3), the first pole piece, the second diaphragm (4), and the second pole piece (5); The second pole piece (5) is cut.

7. A winding device, characterized in that: include: A first cutting mechanism (602) is used to cut the continuous sheet (1) into two cut segments; A first connecting mechanism (603) is used to connect the two cut electrode segments through an adhesive tape (2) to form a first electrode piece; A winding mechanism (7) for winding the first diaphragm (3), the first pole piece, the second diaphragm (4), and the second pole piece (5); The second cutting mechanism (8) is used to perform a fusing process on the stacked first diaphragm (3), the adhesive tape (2), and the second diaphragm (4), so that the first diaphragm (3), the adhesive tape (2), and the second diaphragm (4) are fused and connected at the fusing point.

8. The winding device according to claim 7, characterized in that The second cutting mechanism (8) comprises a hot cutting knife (802), and the hot cutting temperature of the hot cutting knife (802) is 130°C-300°C.

9. The winding device according to claim 8, characterized in that The second cutting mechanism (8) further comprises two heat pressing plates (801) arranged opposite to each other, with a space between the two heat pressing plates (801) for passing the stacked first diaphragm (3), the adhesive tape (2), and the second diaphragm (4).

10. The winding device according to claim 9, characterized in that The hot cutting knife (802) is accommodated in one of the hot pressing plates (801), and the hot cutting knife can extend out of or retract into the hot pressing plate (801) along its cutting direction.

11. A battery cell, characterized in that: It is wound by the winding method described in any one of claims 1 to 6; or, it is prepared by the winding equipment described in any one of claims 7 to 10.

12. A battery, characterized in that: It comprises a shell, and the battery cell as claimed in claim 11 located in the shell.

13. An electrical device, characterized in that: Comprising the battery of claim 12.

Images