CN219457703U - Winding cell structure and secondary battery - Google Patents

Abstract

The utility model belongs to the technical field of secondary batteries, and particularly relates to a winding battery cell structure which comprises a first double-pole piece, an isolating film and a second double-pole piece, wherein the isolating film is used for separating the first double-pole piece and the second double-pole piece, the first double-pole piece, the isolating film and the second double-pole piece are wound to form a battery cell, the first double-pole piece sequentially comprises a first negative pole segment and a first positive pole segment, the second double-pole piece sequentially comprises a second positive pole segment and a second negative pole segment, the first negative pole segment is opposite to the second positive pole segment, and the first positive pole segment is opposite to the second negative pole segment. The winding cell structure is provided with the first double-pole piece and the second double-pole piece, so that a plurality of electrically connected positive and negative pole pairs are formed, the problem of cell matching of a plurality of cells connected in series is avoided, voltage can be increased in multiple, current is more uniform, and rate performance is improved.

Description

Winding cell structure and secondary battery

Technical Field

The utility model belongs to the technical field of secondary batteries, and particularly relates to a winding cell structure and a secondary battery.

Background

Sodium ion batteries are similar to lithium ion batteries in principle, and are called "rocking chair batteries", in which the electrodes consist of a negative electrode sheet and a positive electrode sheet, with solvated ions shuttling between the positive and negative electrodes facing each other. Because the positive current collector of the lithium ion battery uses aluminum foil, the negative current collector uses copper foil, and the lithium battery cells of the lamination process or the winding process can be regarded as parallel connection of multiple layers of cells, the voltage of the single cell is about 3V according to a material system, the voltage of the single cell cannot meet most battery use scenes, and a plurality of cells are required to be connected in series to form a module to improve the total voltage.

For the use scene of small-size energy storage often needs tens of volts of charge-discharge use scenes, often the lithium cell needs a plurality of batteries to establish ties into the module, and the quality problem that the difference of electric core uniformity brought has been enlarged to one side, and on the other hand the structure that the series connection used also takes up more space and weight.

Disclosure of Invention

One of the objects of the present utility model is: aiming at the defects of the prior art, the winding cell structure is provided, the voltage can be increased by times, and the problem of cell matching caused by a plurality of series connection is avoided.

In order to achieve the above purpose, the present utility model adopts the following technical scheme:

the utility model provides a coiling electricity core structure, includes first bipolar plate, barrier film, second bipolar plate, the barrier film is used for separating first bipolar plate and second bipolar plate, first bipolar plate, barrier film, second bipolar plate are convoluteed and are formed the electricity core, first bipolar plate includes the first unilateral pole section of a plurality of end to end connection, first unilateral pole section is including connecting gradually first negative pole section, first insulating layer, first positive pole section, first negative pole section electricity connection of first positive pole section and next first unilateral pole section, the second bipolar plate includes the second unilateral pole section of a plurality of end to end connection, second unilateral pole section is including the second anodal section and the second negative pole section that connect gradually, second anodal section is connected with the second negative pole section electricity, the second anodal section of second negative pole section and next second unilateral pole section passes through the second insulating layer connection, first negative pole section sets up with the second positive pole section is relative, first positive pole section sets up with the second negative pole section is relative. The capacities of the first positive electrode segment and the second positive electrode segment in the battery cell are consistent.

The first negative pole segment of the first double-pole piece, which is close to the middle position of the battery cell, is provided with a negative pole lug, and the second positive pole segment of the second double-pole piece, which is far away from the middle position of the battery cell, is provided with a positive pole lug. According to different conditions, the first double-pole piece can be provided with a negative electrode lug or a positive electrode lug, and the second double-pole piece can be provided with a negative electrode lug or a positive electrode lug. The battery cell is characterized in that a positive lug is arranged on a first positive pole segment, close to the middle position of the battery cell, of a first double-pole piece of the battery cell, and a negative lug is arranged on a second negative pole piece, far away from the middle position of the battery cell, of a second double-pole piece.

The first bipolar plate comprises a first current collector, the first current collector is aluminum foil, the second bipolar plate comprises a second current collector, and the second current collector is aluminum foil.

The first negative electrode segment comprises a first current collector and a first negative electrode active coating arranged on at least one surface of the first current collector; the first positive electrode segment comprises a first current collector and a first positive electrode active coating arranged on at least one surface of the first current collector.

The second negative electrode segment comprises a second current collector and a second negative electrode active coating arranged on at least one surface of the second current collector; the second positive electrode segment comprises a second current collector and a second positive electrode active coating arranged on at least one surface of the second current collector.

Wherein the material of the first insulating layer is one of polypropylene, polyethylene terephthalate and polytetrafluoroethylene; the second insulating layer is made of one of polypropylene, polyethylene terephthalate and polytetrafluoroethylene.

Wherein the component used for the electrical connection is aluminum foil.

The second object of the present utility model is: aiming at the defects of the prior art, the secondary battery is provided with higher voltage, simple structure and good safety.

In order to achieve the above purpose, the present utility model adopts the following technical scheme:

a secondary battery comprises electrolyte, a shell and the winding cell structure, wherein the shell is used for packaging the electrolyte and the winding cell structure. The secondary battery of the utility model can be applied to different active ion batteries, such as sodium ion batteries, potassium ion batteries, lithium ion batteries, calcium ion batteries and the like, and is preferably more suitable for sodium ion batteries and potassium ion batteries, wherein both positive and negative electrodes can use aluminum foils as current collectors.

Wherein the electrolyte is gel polymer electrolyte or solid electrolyte.

Wherein, the material of casing is one of stainless steel, plastic-aluminum membrane or aluminum plate.

Compared with the prior art, the utility model has the beneficial effects that: the winding battery core structure provided by the utility model can increase voltage by times, avoids the battery core matching problem caused by a plurality of series connection, avoids the problem of consistent dictionary of the battery core, reduces the components such as shells, lugs and the like required by series connection without introducing other auxiliary components during connection, and has the advantages of more uniform current and increased multiplying power performance without adopting lugs for series connection.

Drawings

Fig. 1 is a schematic structural view of a wound cell structure of the present utility model.

Fig. 2 is one of the structural schematic diagrams of the winding cell structure of the present utility model in an expanded configuration.

Fig. 3 is a second schematic view showing the unwinding of the winding cell structure of the present utility model.

Fig. 4 is a charge-discharge graph of the secondary battery of the present utility model.

Wherein: 1. a first double-pole piece; 11. a first negative electrode segment; 12. a first positive electrode segment; 13. a first insulating layer; 2. a second double pole piece; 21. a second positive electrode segment; 22. a second negative electrode segment; 23. a second insulating layer; 3. and a separation film.

Detailed Description

Certain terms are used throughout the description and claims to refer to particular components. Those of skill in the art will appreciate that a hardware manufacturer may refer to the same component by different names. The description and claims do not take the form of an element differentiated by name, but rather by functionality. As used throughout the specification and claims, the word "comprise" is an open-ended term, and thus should be interpreted to mean "include, but not limited to. By "substantially" is meant that within an acceptable error range, a person skilled in the art is able to solve the technical problem within a certain error range, substantially achieving the technical effect.

In the description of the present utility model, it should be understood that the directions or positional relationships indicated by the terms "upper", "lower", "front", "rear", "left", "right", "horizontal", etc. are based on the directions or positional relationships shown in the drawings, are merely for convenience of describing the present utility model and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the present utility model.

In the present utility model, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present utility model can be understood by those of ordinary skill in the art according to the specific circumstances.

The present utility model will be described in further detail below with reference to the drawings, but is not limited thereto.

As shown in fig. 1 to 3, a winding battery core structure of this embodiment includes a first bipolar plate 1, an isolating film 3, and a second bipolar plate 2, where the isolating film 3 is used to separate the first bipolar plate 1 and the second bipolar plate 2, the first bipolar plate 1, the isolating film 3, and the second bipolar plate 2 are wound to form a battery core, the first bipolar plate 1 includes a plurality of first single-side pole segments connected end to end, the first single-side pole segments include a first negative pole segment 11, a first insulating layer 13, and a first positive pole segment 12 that are sequentially connected, the first positive pole segment 12 is electrically connected with a first negative pole segment 11 of a next first single-side pole segment, the second bipolar plate 2 includes a plurality of second single-side pole segments connected end to end, the second single-side pole segments include a second positive pole segment 21 and a second negative pole segment 22 that are sequentially connected, the second positive pole segment 22 is electrically connected with the second negative pole segment 22, and the second positive pole segment 22 is disposed opposite to the second positive pole segment 21 and the second positive pole segment 22 that are disposed opposite to the second positive pole segment 11 through the second insulating layer 23.

During preparation, the first double-pole piece 1, the isolating film 3 and the second double-pole piece 2 are sequentially stacked, so that the first negative pole segment 11 in the first double-pole piece 1 and the second positive pole segment 21 in the second double-pole piece 2 are oppositely arranged, a first positive pole segment and a second positive pole segment are formed, sequentially, the first positive pole segment 12 in the first double-pole piece 1 and the second negative pole segment 22 in the second double-pole piece 2 are oppositely arranged, a second positive pole segment and a second positive pole segment are formed, the first double-pole piece 1 and the second double-pole piece 2 sequentially form the positive pole segment and the negative pole segment, during winding, the positive pole segment and the negative pole segment are sequentially wound to form a winding cell structure, the winding cell structure is placed in a shell, and electrolyte is added for packaging, so that the secondary battery is obtained. The single winding electric core of the embodiment is provided with a plurality of positive and negative electrode pairs, each group of positive and negative electrode pairs is a battery unit, the voltage is x volts, the single winding electric core comprises N basic positive and negative electrode pairs, the negative electrode is led out from the negative electrode current collector at the innermost layer of the bare electric core, the positive electrode is led out from the positive electrode current collector at the outermost layer, and the voltage of the whole winding electric core is x times N volts.

The battery core can increase the voltage of the positive electrode pair and the negative electrode pair of the base in a multiplied way, so that the problem of battery core matching caused by series connection of a plurality of battery cores is avoided, and meanwhile, components such as shells and the like required by series connection are reduced; the single battery cell can be multiplied in voltage according to the positive electrode and the negative electrode of the foundation, the battery cell matching problem caused by the series connection of a plurality of battery cells is avoided, the components such as a shell, a tab and the like required by the series connection are reduced, the tab is not adopted for the series connection, the current is more uniform, the multiplying power performance is improved, and as the electrolyte is gel polymer electrolyte or solid electrolyte, a sealing device is avoided between every basic unit in the battery cell.

Taking 32700 cylinder-6.4V sodium ion battery as an example, the preparation method of the sodium ion battery comprises the following steps:

preparation of positive electrode fragment: sodium vanadium phosphate: the conductive carbon black SP and the polyvinylidene fluoride PVDF are mixed and coated on two sides of the aluminum foil according to the mass ratio of 90:5:5, as shown in figure 3, the A surface and the B surface are staggered, the A surface is reserved with a 72mm empty foil area, and the B surface is reserved with a 94mm empty foil area. And drying and rolling the pole piece to obtain the positive pole segment.

The negative electrode segment is made of hard carbon: sodium alginate is mixed and coated on two sides of an aluminum foil according to the mass ratio of 90:10, one end of a A, B surface is aligned, and an empty foil area of 11mm is reserved on the A surface of the other end as shown in fig. 3. And drying and rolling the pole piece to obtain a negative pole segment.

As shown in fig. 3, the negative electrode segment is composed of hard carbon: the sodium alginate is prepared by mixing and coating sodium alginate on one end of an aluminum foil according to the mass ratio of 90:10, and aligning two sides. Sodium vanadium phosphate: and (3) mixing and coating conductive carbon black SP and polyvinylidene fluoride PVDF on the other end of the aluminum foil according to the mass ratio of 90:5:5, and reserving 68mm empty aluminum foil on the B surface to prepare the positive electrode segment. And connecting the negative electrode segment and the positive electrode segment according to the figure 3, drying and rolling to obtain a first double-electrode plate. The first positive electrode segment and the first negative electrode segment in the first bipolar plate are connected through insulating glue. And preparing the second double-pole piece by the same method.

And placing the first bipolar plate, the second bipolar plate and the isolating film according to the structure shown in fig. 3, completely surrounding the second bipolar plate by the diaphragm, and winding from the left side to prepare the bare cell. The positive electrode tab of the first double-pole piece in the bare cell is led out by the first positive electrode segment, the negative electrode tab is led out by the first negative electrode segment, and the second double-pole piece does not lead out the tab.

Electrolyte mixed solution: 1) Uniformly mixing ethylene carbonate, propylene carbonate, methyl ethyl carbonate and diethyl carbonate according to a mass ratio of 2:1:4:3 to prepare an organic solvent; 2) Then taking an organic solvent accounting for 85 percent of the total mass of the liquid mixed solution, and adding polyethylene glycol diacrylate accounting for 1 percent of the total mass of the liquid mixed solution, polyethylene glycol diacrylate accounting for 1.5 percent, methyl methacrylate accounting for 0.5 percent and ethylene vinyl sulfite additive accounting for 0.3 percent and azodiisobutyronitrile initiating agent accounting for 0.2 percent of the total mass of the liquid mixed solution; 3) Slowly adding the mixture of sodium hexafluorophosphate and sodium difluorosulfimide to prepare a sodium salt solution with the concentration of 1mol/L, wherein the sodium hexafluorophosphate accounts for 11.0% of the total mass of the liquid mixed solution, and uniformly mixing to prepare the liquid mixed solution.

The bare cell was placed in a 32700 steel can. And injecting the electrolyte mixed solution into the battery cell. And after the cell is placed in vacuum and is kept at a high temperature of 40 ℃ for 24 hours, the electrolyte mixed solution is fully soaked.

And (3) the cell liquid injection port is downward, the cell is vacuumized, residual electrolyte is pumped out, then the cell main body is heated to 80 ℃ and kept for 2 hours, the electrolyte mixed liquid is completely solidified, and then the cell is packaged.

And after the battery is formed, a finished battery cell is obtained, and the charge-discharge capacity versus voltage curve of the battery is shown in figure 3.

The first negative electrode segment 11 of the first bipolar plate 1, which is close to the middle position of the battery cell, is provided with a negative electrode lug, and the second positive electrode segment 21 of the second bipolar plate 2, which is far away from the middle position of the battery cell, is provided with a positive electrode lug.

The first double pole piece 1 of the embodiment comprises a first current collector, the first current collector is an aluminum foil, the second double pole piece 2 comprises a second current collector, and the second current collector is an aluminum foil. In the embodiment, the first double-pole piece 1 and the second double-pole piece 2 both adopt aluminum foils as current collectors, so that the preparation of the sodium ion battery is facilitated, and the voltage of the single battery cell can be more than 3V.

The first negative electrode segment 11 of the present embodiment includes a first current collector and a first negative electrode active coating layer disposed on at least one surface of the first current collector; the first positive electrode segment 12 includes a first current collector and a first positive electrode active coating disposed on at least one surface of the first current collector. The first negative electrode plate comprises a first current collector and a first negative electrode active coating arranged on at least one surface of the first current collector, and the length of the first negative electrode active coating is set according to the requirement, so that the first negative electrode active coating has different lengths on two sides of the first negative electrode plate, and the surfaces of the two sides have different AB surfaces, thereby being convenient to use. The first positive plate comprises a first current collector and a first positive active coating arranged on at least one surface of the first current collector, and the length of the first positive active coating is set according to the requirement, so that the surfaces of two sides are provided with different AB surfaces, and the use is convenient.

The second negative electrode segment 22 of the present embodiment includes a second current collector and a second negative electrode active coating layer disposed on at least one surface of the second current collector; the second positive electrode segment 21 includes a second current collector and a second positive electrode active coating disposed on at least one surface of the second current collector. Similarly, the length of the second negative electrode active coating is designed according to the requirement, so that the second negative electrode sheet has different AB surfaces, and the use is convenient. And designing the length of the second positive electrode active coating according to the requirement, so that the second positive electrode plate has different AB values, and the use is convenient.

The material of the first insulating layer 13 in this embodiment is one of polypropylene, polyethylene terephthalate and polytetrafluoroethylene; the second insulating layer 23 is made of one of polypropylene, polyethylene terephthalate and polytetrafluoroethylene. The first insulating layer 13 can separate the first negative electrode segment 11 from the first positive electrode segment 12 in the first bipolar plate 1, so that no electric connection is formed, the first negative electrode segment 11 and the second positive electrode segment 21 in the second single-side electrode segment form a positive electrode pair, the first positive electrode segment 12 and the second negative electrode segment 22 in the second single-side electrode segment form a positive electrode pair, and the two positive electrode pair are sequentially connected, thereby avoiding external parts, avoiding the problem of battery core assembly, and forming a double increase in the voltage of the wound battery.

The component used for the electrical connection of this embodiment is aluminum foil. The aluminum foil is directly used for carrying out the battery, the aluminum foil is the same as the current collector in material, the battery difference caused by different materials is avoided, and the stability of the battery is improved.

The secondary battery of the embodiment comprises electrolyte, a shell and the winding cell structure, wherein the shell is used for packaging and installing the electrolyte and the winding cell structure. A secondary battery has higher voltage, simple structure and good safety. The secondary battery prepared by the method is subjected to charge and discharge test, and the test result is recorded in fig. 4. It can be obtained from fig. 4 that the embodiment adopts two positive and negative electrode pairs, the voltage of the single battery core is increased to 6.4V, no redundant sealing element exists in the battery, the charge and discharge curve is good, and no short circuit behavior exists.

The electrolyte of the present embodiment is a gel polymer electrolyte or a solid electrolyte. And a gel polymer electrolyte or a solid electrolyte is used, a sealing device is omitted between every two basic units in the battery core, and compared with a conventional sodium ion battery, the middle section is provided with a circle of aluminum foil and one section of insulating layer, and the energy density is similar to that of the conventional sodium ion battery.

The material of the shell in this embodiment is one of stainless steel, an aluminum plastic film or an aluminum plate. Preferably, the housing is a square stainless steel housing.

While the foregoing description illustrates and describes several preferred embodiments of the present utility model, it is to be understood that the utility model is not limited to the forms disclosed herein, but is not to be construed as limited to other embodiments, and is capable of numerous other combinations, modifications and environments and is capable of changes or modifications within the scope of the inventive concept as described herein, either as a result of the foregoing teachings or as a result of the knowledge or technology in the relevant art. And that modifications and variations which do not depart from the spirit and scope of the utility model are intended to be within the scope of the appended claims.

Claims (10)

1. The utility model provides a coiling electricity core structure, its characterized in that includes first bipolar plate, barrier film, second bipolar plate, the barrier film is used for separating first bipolar plate and second bipolar plate, first bipolar plate, barrier film, second bipolar plate are convoluteed and are formed the electricity core, first bipolar plate includes the first unilateral pole section of a plurality of end to end connection, first unilateral pole section is including connecting gradually first negative pole section, first insulating layer, first positive pole section, first negative pole section electricity of first unilateral pole section of first and next, the second bipolar plate includes the second unilateral pole section of a plurality of end to end connection, second unilateral pole section includes the second anodal section and the second negative pole section of connecting gradually, second anodal section is connected with the second negative pole section electricity, the second anodal section is connected through the second insulating layer with the second anodal section of next second unilateral pole section, first negative pole section sets up with the second anodal section is relative, first positive pole section sets up with the second negative pole section is relative.

2. The winding cell structure according to claim 1, wherein a first negative electrode segment of the first double-pole piece, which is close to a middle position of the cell, is provided with a negative electrode tab, and a second positive electrode segment of the second double-pole piece, which is far away from the middle position of the cell, is provided with a positive electrode tab.

3. The wound cell structure of claim 1, wherein the first bipolar plate comprises a first current collector, the first current collector being aluminum foil, the second bipolar plate comprising a second current collector, the second current collector being aluminum foil.

4. The wound cell structure of claim 3, wherein the first negative electrode segment comprises a first current collector and a first negative electrode active coating disposed on at least one surface of the first current collector; the first positive electrode segment comprises a first current collector and a first positive electrode active coating arranged on at least one surface of the first current collector.

5. The wound cell structure of claim 3, wherein the second negative electrode segment comprises a second current collector and a second negative electrode active coating disposed on at least one surface of the second current collector; the second positive electrode segment comprises a second current collector and a second positive electrode active coating arranged on at least one surface of the second current collector.

6. The winding cell structure according to claim 1, wherein the first insulating layer is made of one of polypropylene, polyethylene terephthalate and polytetrafluoroethylene; the second insulating layer is made of one of polypropylene, polyethylene terephthalate and polytetrafluoroethylene.

7. The coiled cell structure of claim 1, wherein the component used for the electrical connection is aluminum foil.

8. A secondary battery comprising an electrolyte, a housing and the wound cell structure of any one of claims 1-7, the housing being configured to encapsulate the electrolyte and the wound cell structure.

9. The secondary battery according to claim 8, wherein the electrolytic solution is a gel polymer electrolyte or a solid electrolyte.

10. The secondary battery according to claim 8, wherein the case is made of one of stainless steel, an aluminum plastic film, and an aluminum plate.