A pole piece, a process flow, a secondary battery using the pole piece, and a production device

Abstract

The present invention belongs to the technical field of secondary batteries, and specifically relates to a pole piece, a process flow, a secondary battery using the pole piece, and a production device. The pole piece includes a current collector, and the current collector includes an insulating layer and a first conductor layer and a second conductor layer respectively arranged on both sides of the insulating layer; the first conductor layer has a first blank area and a first active material coating layer in parallel on the outward side; the second conductor layer has a second blank area and a second active material coating layer in parallel on the outward side; the first blank area is provided with a folding area, which is suitable for folding the current collector 180 degrees and the second blank area covers the first blank area; a conductive connector, one end of which extends out of the folding area and is connected to the first blank area, and the other end is connected to the second blank area of ​​the folding area, which is suitable for electrically connecting the first blank area and the second blank area. This pole piece has the effect of improving the safety of secondary batteries and facilitating production.

Description

Technical Field

[0001] The present invention belongs to the technical field of secondary batteries, and in particular relates to a pole piece, a process flow, a secondary battery using the pole piece, and production equipment. Background Art

[0002] A secondary battery (Rechargeable battery), also known as a rechargeable battery or storage battery, refers to a battery that can be recharged to activate the active material after being discharged and continue to be used.

[0003] Secondary batteries are batteries that utilize the reversibility of chemical reactions, that is, after chemical reactions are converted into electrical energy, electrical energy can be used to repair the chemical system, and then chemical reactions can be used to convert electrical energy again, so they are called secondary batteries (rechargeable batteries). The main rechargeable batteries on the market include nickel-metal hydride batteries, nickel-cadmium batteries, lead-acid (or lead storage) batteries, lithium-ion batteries, polymer lithium-ion batteries, etc.

[0004] Among them, lithium-ion batteries are composed of a basic unit structure consisting of a positive electrode / diaphragm / negative electrode that is wound or stacked. The positive electrode and the negative electrode undergo a chemical reaction to form an electric current, which is then collected and conducted through the current collectors in the positive and negative electrodes; the diaphragm is responsible for separating the positive and negative electrodes to prevent the positive and negative electrodes from contacting and short-circuiting. When the battery is impacted, squeezed and deformed, it will break. Traditional metal current collectors can easily pierce the diaphragm, causing a short circuit inside the battery, resulting in combustion and explosion. In order to improve battery safety, technicians composite metal conductor layers on both sides of the polymer support to form a composite current collector. This composite current collector can reduce the probability of breakage and puncture. However, since the polymer in the middle of the composite current collector has a high resistance, the conductor layers on both sides are insulated from each other, making it difficult to conduct the current together.

[0005] In the prior art, the invention with application publication number CN102856558A discloses a current collector and a non-aqueous secondary battery, which has a folded area formed by folding the end of a multilayer structure formed by sandwiching an insulating layer with a conductive layer more than twice in the same direction, wherein in the folded area, the conductive layers sandwiching the insulating layer are electrically connected to each other, and the inner surfaces of the end of the current collector forming the folded area are separated or partially in contact.

[0006] The above-mentioned prior art solutions have the following defects: first, during the production process of this type of current collector, it is necessary to first cut the long strip of current collector raw material into several separate current collector raw materials, and then roll the separate current collector raw materials 360 degrees for welding. Among them, because the strip-shaped current collector raw material needs to be cut before processing and production, it is not conducive to streamlined continuous processing and production; secondly, the rolled-up part needs to be welded during processing, and the rolled-up part cannot fit the welding part well because of its own curling, resulting in weak welding and poor welding effect; finally, due to the small thickness of the conductor layer, it is difficult to ensure the welding strength when welding two thinner layers of metal, and the reliability is very poor. Summary of the invention

[0007] The object of the present invention is to provide a pole piece which has the advantages of improving the safety of a secondary battery using the pole piece and facilitating automated continuous production.

[0008] In order to solve the above technical problems, the present invention provides a pole piece, wherein the current collector comprises an insulating layer and a first conductor layer and a second conductor layer respectively arranged on both sides of the insulating layer;

[0009] The first conductor layer has a first blank area and a first active material coating layer in parallel on one side facing outward;

[0010] The second conductor layer has a second blank area and a second active material coating layer in parallel on its outward side;

[0011] The first blank area is provided with a folding area suitable for folding the current collector and the second blank area partially covers the first blank area;

[0012] The conductive connector is located in the folded area, one end of which extends out of the folded area and is connected to the first blank area, and the other end of which is connected to the second blank area of ​​the folded area, and is suitable for electrically connecting the first blank area and the second blank area.

[0013] Furthermore, the insulating layer is made of one or more of polyester, polyethylene, polypropylene, and polyarylsulfone.

[0014] Furthermore, the conductive connector is connected by ultrasonic welding.

[0015] Furthermore, the folding angle of the current collector is 180 degrees.

[0016] Furthermore, the conductive connector is a tab.

[0017] On the other hand, the present invention also provides a process flow of a pole piece, the steps of which are:

[0018] Step 1: The active material is disposed on the first conductor layer of the current collector to form a first active material coating layer and a first blank area; the active material is disposed on the second conductor layer to form a second active material coating layer and a second blank area;

[0019] Step 2: Folding a portion of the first blank area of ​​the current collector so that the current collector is located at the first blank area to form a folded area;

[0020] Step 3: Connect one end of the conductive connector to the first blank area, and the other end to the folded second blank area.

[0021] Furthermore, in step 1, the active material is arranged at intervals on the strip-shaped first conductor to form a plurality of first active material coating layers, and a first blank area is formed between adjacent first active material coating layers; the active material is arranged at intervals on the strip-shaped second conductor to form a plurality of second active material coating layers, and a second blank area is formed between adjacent second active material coating layers, and a strip-shaped continuous current collector including a plurality of semi-finished active material coating layers and blank areas connected end to end is mass-produced;

[0022] In step 2, a first blank area of ​​a single current collector among a plurality of continuous strip-shaped current collectors is partially cut, a folding action is performed by a folding device, so that the current collector is located at the first blank area to form a folding area, and the strip-shaped current collectors are cut in sequence;

[0023] In step three, the conductive connector is placed in the folded area, one end of the conductive connector is welded to the first blank area, and the other end is welded to the folded second blank area to form a strip-shaped continuous electrode piece connected end to end;

[0024] New step 4: Cut the welded and processed strip-shaped continuous electrode into single electrode pieces, or wind the electrode pieces and diaphragms together to form a dry battery cell and then cut them.

[0025] Furthermore, in step three, the folding device is flipped by a mechanical arm and driven by a stepper motor.

[0026] In a third aspect, the present invention further provides a secondary battery using the electrode sheet, comprising: a positive electrode sheet, a separator and a negative electrode sheet laminated in sequence, and an electrolyte; wherein:

[0027] At least one of the positive electrode sheet and the negative electrode sheet adopts the electrode sheet as described above.

[0028] Furthermore, when a pole piece as described above is used as the positive pole piece, the conductor layer is aluminum or aluminum alloy.

[0029] Furthermore, when a pole piece as described above is used as the negative pole piece, the conductor layer is copper or a copper alloy.

[0030] In a fourth aspect, the present invention further provides a production device for a modified electrode, comprising:

[0031] Unwinding roller, forming mechanism, folding mechanism, conductive connector attaching mechanism, ultrasonic welding device and receiving roller;

[0032] The unwinding roller is suitable for placing rolled pole piece raw materials;

[0033] A feeding mechanism is provided between the unwinding roller and the receiving roller, which is suitable for feeding the strip-shaped electrode material unwinding from the rolled electrode material to the receiving roller;

[0034] The forming mechanism is suitable for forming a foldable cutout on the strip-shaped electrode material;

[0035] The folding mechanism is suitable for folding strip-shaped electrode material;

[0036] The conductive connecting body attaching mechanism is suitable for attaching the conductive connecting body to the strip-shaped electrode material;

[0037] The ultrasonic welding device is suitable for ultrasonically welding the conductive connector to the strip-shaped pole piece material.

[0038] The beneficial effects of the present invention are:

[0039] 1. The present invention has a structure of folding 180 degrees and welding the conductive connector, which reduces the folding angle and has fewer processes, and has low requirements for processing equipment. At the same time, during the processing, it is only folded 180 degrees, which makes it easier for processing equipment to control the folding angle, reduces processing difficulty, and increases process reliability.

[0040] 2. The current collector has a folding area that can be folded 180 degrees. During processing, only part of the long current collector needs to be cut without cutting. The long current collector can be rolled up and matched with the subsequent dry battery cell continuous automatic winding process, so that the pole pieces and dry battery cells can be produced continuously during the processing and manufacturing process, thereby improving production automation.

[0041] 3. The conductive connector whose two ends are respectively welded to the first blank area and the second blank area can realize electrical connection between the first conductor and the second conductor and conduct the imported current, and improve the connection stability between the first conductor layer and the second conductor layer.

[0042] 4. The conductive connector has a thicker thickness and can be welded to a thinner conductor layer to improve welding reliability.

[0043] 5. Through special equipment, the current collector is produced on an automated assembly line to improve production efficiency and reduce labor costs.

[0044] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0046] Figure 1 It is a schematic diagram of the structure of the pole piece of the present invention;

[0047] Figure 2 is a side view of a pole piece of the present invention;

[0048] Figure 3 is a schematic structural diagram of a pole piece according to Embodiment 1 of the present invention;

[0049] Figure 4 is a schematic structural diagram of a pole piece according to Embodiment 2 of the present invention;

[0050] Figure 5 is a schematic structural diagram of a pole piece according to Embodiment 3 of the present invention;

[0051] Figure 6 is a schematic structural diagram of a secondary battery according to Embodiment 5 of the present invention;

[0052] Figure 7 It is a structural schematic diagram of the continuous structure of the pole piece of the present invention;

[0053] Figure 8 It is a structural schematic diagram of the production equipment of the present invention.

[0054] In the figure:

[0055] 1. current collector; 11. insulating layer; 12. first conductor layer; 13. second conductor layer;

[0056] 2. a first blank area; 21. a first active material coating layer;

[0057] 3. a second blank area; 31. a second active material coating layer;

[0058] 4. Folding area;

[0059] 5. Conductive connector;

[0060] 6. Positive electrode;

[0061] 7. Diaphragm;

[0062] 8. Negative electrode;

[0063] 9. Unwinding roller; 91. Receiving roller; 92. Feeding mechanism;

[0064] 10. Forming mechanism; 101. Folding mechanism; 102. Conductive connector attaching mechanism; 103. Ultrasonic welding device. DETAILED DESCRIPTION

[0065] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0066] Embodiment 1:

[0067] like Figure 1 and Figure 2 As shown, a pole piece includes: a current collector 1, the current collector 1 includes an insulating layer 11 and a first conductor layer 12 and a second conductor layer 13 respectively arranged on both sides of the insulating layer 11, and the current on the current collector 1 is led out by connecting the first conductor layer 12 and the second conductor layer 13. A first blank area 2 and a first active material coating layer 21 are arranged in parallel on the outward side of the first conductor layer 12; a second blank area 3 and a second active material coating layer 31 are arranged in parallel on the outward side of the second conductor layer 13. The insulating layer 11 is made of one or more constituent materials selected from polyester, polyethylene, polypropylene, and polyarylsulfone. In this embodiment, the insulating layer 11 can be made of, but not limited to, polyester. The first active material coating layer 21 and the second active material coating layer 31 are both coated with active materials.

[0068] In order to electrically connect the first blank area 2 and the second blank area 3, a folded area 4 is formed on the first blank area 2 by folding the current collector 1 by 180 degrees, and at the same time, the second blank area 3 at the folded area 4 covers the first blank area 2. A conductive connector 5 is provided in the folded area 4, one end of the conductive connector 5 extends out of the folded area 4 and is connected to the first blank area 2, and the other end is connected to the second blank area 3 of the folded area 4, and current is derived or introduced from the current collector 1. In this embodiment, the conductive connector 5 can be, but not limited to, a tab, and the connection method of the conductive connector 5 can be, but not limited to, ultrasonic welding.

[0069] In this embodiment, if Figure 1 As shown, the folded area 4 is in the shape of a strip, that is, two vertical parallel tangent lines are cut on the current collector 1, and then the cut portion of the strip is folded vertically.

[0070] In summary: See Figure 2 and Figure 3 The continuous strip current collector 1 can be partially cut and then folded through the folding area 4, so that the current collector 1 does not need to be completely cut during the production process, and has the advantage of continuous production for the production process of the assembly line. The first blank area 2 and the second blank area 3 are connected by welding the conductive connector 5, and the connection is more stable and has higher connection stability.

[0071] Embodiment 2:

[0072] like Figure 4 As shown, a pole piece is different from the embodiment 1 in that the cutting strip is L-shaped and the folding area 4 is folded horizontally.

[0073] Embodiment 3:

[0074] like Figure 5 As shown, a pole piece is different from Example 1 in that the cutting strip is a vertical tangent line and the folding area 4 is folded obliquely.

[0075] Embodiment 4:

[0076] A process flow of a pole piece, the steps are:

[0077] Step 1: The active material is disposed on the first conductor layer 12 of the current collector 1 to form a first active material coating layer 21 and a first blank area 2; the active material is disposed on the second conductor layer 13 to form a second active material coating layer 31 and a second blank area 3;

[0078] Step 2: Folding a portion of the first blank area 2 of the current collector 1 so that the current collector 1 is located at the first blank area 2 to form a folded area 4;

[0079] Step 3: Connect one end of the conductive connector 5 to the first blank area 2 , and the other end to the folded second blank area 3 .

[0080] In order to realize the automated production of production equipment, the following improvements are made to the process flow:

[0081] In step 1, the active material is arranged at intervals on the strip-shaped first conductor to form a plurality of first active material coating layers 21, and a first blank area 2 is formed between adjacent first active material coating layers 21; the active material is arranged at intervals on the strip-shaped second conductor to form a plurality of second active material coating layers 31, and a second blank area 3 is formed between adjacent second active material coating layers 31, and a strip-shaped continuous current collector 1 including a plurality of semi-finished active material coating layers and blank areas connected end to end is mass-produced;

[0082] In step 2, the first blank area 2 of a single current collector 1 among a plurality of continuous strip-shaped current collectors 1 is partially cut, and a folding action is performed by a folding device so that the current collector 1 is located at the first blank area 2 to form a folding area 4, and the strip-shaped current collectors 1 are cut in sequence;

[0083] In step three, the conductive connector 5 is placed in the folded area 4, one end of the conductive connector 5 is welded to the first blank area 2, and the other end is welded to the folded second blank area 3, so as to form a strip-shaped continuous electrode piece connected end to end;

[0084] New step 4: cutting the welded and processed strip-shaped continuous electrode pieces into single electrode pieces, or winding the electrode pieces and the diaphragm 7 together to form a dry battery cell and then cutting them.

[0085] Among them, in step three, the folding device uses a mechanical arm to flip, which is driven by a stepper motor. The stepper motor drives the mechanical arm to flip 180 degrees to fold the current collector 1 to form a folding area 4.

[0086] In summary, the current collector 1 needs to be cut for curling and welding, and the processing steps in this embodiment can automatically process the entire long strip of raw material. After the processing is completed, it can be cut according to the use requirements.

[0087] Embodiment 5:

[0088] like Figure 6 As shown, a secondary battery using the electrode sheet includes: a positive electrode sheet 6, a separator 7 and a negative electrode sheet 8 bonded in sequence, and also includes an electrolyte; wherein at least one of the positive electrode sheet 6 and the negative electrode sheet 8 adopts the electrode sheet used in Example 1.

[0089] Specifically, when a pole piece as described in Example 1 is used as the positive pole piece 6, the conductor layer is aluminum or aluminum alloy. When a pole piece as described in Example 1 is used as the negative pole piece 8, the conductor layer is copper or copper alloy.

[0090] Embodiment 6:

[0091] like Figure 8 As shown, a production equipment for modified electrode sheets includes a discharge roller 9, a forming mechanism 10, a folding mechanism 101, a conductive connector 5 attaching mechanism, an ultrasonic welding device 103 and a receiving roller 91 which are placed in sequence. The discharge roller 9 is suitable for placing rolled electrode sheet materials. Users can place rolled electrode sheet materials on the discharge roller 9, and release the rolled electrode sheet materials through a feeding mechanism 92 arranged between the discharge roller 9 and the receiving roller 91, process them and finally send them to the receiving roller 91. The feeding mechanism 92 can be, but is not limited to, a belt conveyor driven by a driving motor.

[0092] In this embodiment, the forming mechanism 10 may use, but is not limited to, an automatically controlled shearing device to cut the interval portion of the strip electrode material;

[0093] In this embodiment, the folding mechanism 101 can use but is not limited to a stepper motor to drive a robotic arm to fold the electrode material at the shearing position; the conductive connector 5 sticking mechanism can use but is not limited to a cylinder to push the conductive connector 5 and a photoelectric induction conveyor belt to continuously transport the conductive connector 5 to the end of the cylinder's piston rod to stick the conductive connector 5 onto the strip electrode material.

[0094] In this embodiment, the ultrasonic welding device 103 may be, but is not limited to, an ultrasonic welding device to ultrasonically weld the conductive connector 5 to the strip electrode material.

[0095] To summarize: the user places the rolled electrode raw material on the unwinding roller 9, and continuously conveys the electrode raw material through the feeding mechanism 92, cuts part of the strip electrode at intervals through the forming mechanism 10, folds the cut part through the folding mechanism 101, and sticks the conductive connector 5 on the folded part through the conductive connector 5 sticking mechanism, then welds the conductive connector 5 to the electrode through the ultrasonic welding device 103, and rolls up the processed strip electrode through the receiving roller 91.

[0096] The various devices selected in this application are all universal standard parts or parts known to those skilled in the art, and their structures and principles can be known to those skilled in the art through technical manuals or conventional experimental methods.

[0097] In the description of the embodiments of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0098] Based on the above ideal embodiments of the present invention, the relevant staff can make various changes and modifications without departing from the technical concept of the present invention through the above description. The technical scope of the present invention is not limited to the contents of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A process flow of a pole piece, characterized in that: The steps are: Step 1: the active material is arranged on the first conductor layer of the current collector (1) to form a first active material coating layer (21) and a first blank area (2); the active material is arranged on the second conductor layer to form a second active material coating layer (31) and a second blank area (3); In step 1, the active material is arranged at intervals on the strip-shaped first conductor layer to form a plurality of first active material coating layers (21), and a first blank area (2) is formed between adjacent first active material coating layers (21); the active material is arranged at intervals on the strip-shaped second conductor layer to form a plurality of second active material coating layers (31), and a second blank area (3) is formed between adjacent second active material coating layers (31), and a strip-shaped continuous current collector (1) including a plurality of semi-finished active material coating layers and blank areas connected end to end is mass-produced; Step 2: folding a portion of the first blank area (2) of the current collector (1) so that the current collector (1) is located at the first blank area (2) to form a folded area (4); In step 2, a first blank area (2) of a single current collector (1) among a plurality of continuous strip-shaped current collectors is partially cut, a folding action is performed by a folding device, so that the current collector (1) is located at the first blank area (2) to form a folding area (4), and the strip-shaped current collectors are cut in sequence; Step 3: Connect one end of the conductive connector (5) to the first blank area (2), and the other end to the folded second blank area (3); In step three, the conductive connector (5) is placed in the folded area (4), one end of the conductive connector (5) is welded to the first blank area (2), and the other end is welded to the folded second blank area (3), so as to form a strip-shaped continuous electrode piece connected end to end; Step 4: Cut the welded and processed strip-shaped continuous electrode into single electrode pieces, or wind the electrode pieces and diaphragms together to form a dry battery cell and then cut them.

2. A process flow of a pole piece as claimed in claim 1, characterized in that: in, In step 2, the folding device is flipped by a mechanical arm and driven by a stepper motor.

3. A pole piece, comprising: A current collector (1), characterized in that it is made according to the process flow of the pole piece as described in any one of claims 1 to 2.

4. A secondary battery using a pole piece, characterized in that: include: A positive electrode sheet (6), a separator (7) and a negative electrode sheet (8) laminated in sequence, and also comprising an electrolyte; in, At least one of the positive electrode sheet (6) and the negative electrode sheet (8) is a sheet as claimed in claim 3.

5. A secondary battery using a pole piece as claimed in claim 4, characterized in that: In the positive electrode plate (6), the conductor layer is aluminum or an aluminum alloy.

6. A secondary battery using a pole piece as claimed in claim 5, characterized in that: In the negative electrode plate (8), the conductor layer is copper or a copper alloy.

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