Battery cell structure, battery and battery module

Abstract

The utility model relates to the technical field of lithium ion batteries, in particular to a battery and a battery module. The first bending part of the battery cell structure is provided with the concave part and the convex part, so that a gap between the first bending part and the adjacent second bending part is increased, and the storage capacity of electrolyte in the arc area is improved, so that the fluidity of the electrolyte in the arc area is improved, and the service life of the battery cell structure is prolonged on the premise of not changing the capacity of the battery. The lithium precipitation problem existing in the arc area of the battery is solved. The utility model also provides a battery and a battery module.

Description

TECHNICAL FIELD

[0001] The utility model relates to lithium ion battery technical field especially relates to a kind of electric core structure, battery and battery module. BACKGROUND

[0002] Lithium ion battery is a new type of chemical power supply with high energy density, high power density and long life, etc., is widely used in electric vehicles, mobile communication, portable electronic equipment and other fields.Winding electric core is a common lithium ion battery electrode assembly form, its manufacturing process will be positive sheet, negative sheet and isolation film be rolled together by winding machine, adjacent positive and negative sheet is isolated by isolation film.Winding electric core has the advantages of compact structure, low cost, high production efficiency, but also has the problem that corner is prone to lithium precipitation.

[0003] Lithium precipitation refers to the phenomenon that part of lithium ions cannot be embedded in negative electrode material when lithium ion battery is charged, and metal lithium is formed on the surface of negative electrode.Positive and negative sheet of winding electric core arc region is extruded, resulting in the gap between positive and negative sheet becomes small, so that the wettability or flowability of electrolyte in arc region is poor, which affects the embedding of lithium ions, so lithium precipitation phenomenon occurs.Lithium precipitation phenomenon can cause battery performance degradation, cycle life shortening and the like. UTILITY MODEL CONTENTS

[0004] In order to solve the problems and deficiencies in the prior art, the utility model provides an electric core structure, a battery and a battery module.The above-mentioned electric core structure includes a positive sheet, a negative sheet and a separator, and the separator is used to isolate the positive sheet and the negative sheet.

[0005] The positive sheet, the negative sheet and the separator are wound into a battery.

[0006] The battery includes an arc region and a straight region; the positive sheet includes a plurality of first bending parts located in the arc region, and the negative sheet includes a plurality of second bending parts located in the arc region; the first bending part is provided with an embossed region, the embossed region has a concave part and a convex part, the concave part is located on the inner side of the bending of the first bending part, and the convex part is located on the outer side of the bending of the first bending part.

[0007] Optionally, the positive sheet includes a positive active material layer and a positive current collector, and the positive active material layer and the positive current collector of the embossed region are deformed as a whole to form the concave part and the convex part.

[0008] Optionally, the length of the embossed region is 2mm-10mm.

[0009] Optionally, the width of the concave part is 0.5mm-2.0mm.

[0010] Optionally, the depth of the recess is 10% to 40% of the thickness of the positive active material layer.

[0011] Optionally, the interval between two adjacent recesses is 0.5mm to 2.0mm.

[0012] Optionally, the recess is spherical cap-shaped.

[0013] Optionally, the recesses are distributed in a matrix form at the first bending part.

[0014] Further, the utility model also provides a battery, the battery includes the battery of any one in above.

[0015] Further, the utility model also provides a battery module, the battery module includes the battery of above.

[0016] Compared with the prior art, the utility model has the beneficial effects that:

[0017] The embossed area is arranged at the first bending part of the positive sheet, compared with not arranging the embossed area, the recess on the first bending part and the gap between its adjacent second bending part, the gap between the convex part on the first bending part and the adjacent second bending part are all larger, there is more electrolyte storage space between the first bending part and the adjacent second bending part, more electrolyte can be stored, the flowability of the electrolyte in the arc area is improved, so that the problem of lithium precipitation existing in the arc area of the battery is improved without changing the size and capacity of the battery.

[0018] The above and other objects, advantages and features of the utility model will become more apparent from the following detailed description of some embodiments thereof, taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0019] Some specific embodiments of the utility model will be described in detail hereinafter with reference to the accompanying drawings in an exemplary and non-restrictive manner. The same reference signs in the drawings indicate the same or similar components or parts. Those skilled in the art should understand that these drawings are not necessarily drawn to scale. In the drawings:

[0020] Figure 1 is the structural schematic view of the cell structure of one embodiment of the utility model;

[0021] Figure 2 is the partial structural schematic view of the cell structure of one embodiment of the utility model;

[0022] Figure 3 is the front view of the positive sheet and negative sheet of one embodiment of the utility model;

[0023] Figure 4 is a top view of the positive plate of one embodiment of the present application;

[0024] Figure 5 is a top view of the embossed region of one embodiment of the present application;

[0025] Figure 6 is a front view of the embossed region of one embodiment of the present application.

[0026] In the figure: 10 - cell structure, 11 - arc region, 12 - flat region; 20 - positive plate, 21 - first bending part, 22 - embossed region, 221 - concave part, 222 - convex part, 23 - positive current collector, 24 - positive active material layer; 30 - diaphragm; 40 - negative plate, 41 - second bending part. DETAILED DESCRIPTION

[0027] The cell structure, battery and battery module of the embodiments of the present application will be described below with reference to Figures 1 to 6 In the description of the embodiments, it should be understood that the terms "first", "second" are used only for the purpose of description, and should not be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined as "first", "second" can explicitly or implicitly include at least one of the features, i.e. one or more of the features. In the description of the present application, the meaning of "a plurality of" is at least two, such as two, three, etc., unless otherwise specifically limited. When a certain feature "includes or contains" a certain or certain features, unless otherwise specifically described, it indicates that other features and can further include other features.

[0028] In the description of the embodiments, the description of the terms "one embodiment", "some embodiments", "illustrative embodiment", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0029] Figure 1 is a partial schematic view of a battery according to one embodiment of the present application. As shown in Figure 1 and in combination with Figures 2 to 6The utility model provides a kind of electric core structure 10, battery and battery module.The above-mentioned battery includes positive sheet 20, negative sheet 40 and diaphragm 30, the diaphragm 30 is used to isolate the positive sheet 20 and the negative sheet 40.Positive sheet 20, negative sheet 40 and diaphragm 30 are wound into battery.Battery includes circular arc area 11 and flat area 12;Positive sheet 20 includes multiple first bending part 21 located in circular arc area 11, and negative sheet 40 includes multiple second bending part 41 located in circular arc area 11.Press area 22 is provided on first bending part 21, and press area 22 has recess 221 and convex part 222.Recess 221 is located in the bending inside of first bending part 21;Convex part 222 is located in the bending outside of first bending part 21.

[0030] Specifically, diaphragm 30 forms spacing to positive sheet 20 and negative sheet 40, to avoid that positive sheet 20 and negative sheet 40 directly contact during winding.Positive sheet 20 is provided with at least one press area 22, and press area 22 is located in circular arc area 11 after winding into battery, and the bending inside of first bending part 21 is wrapped adjacent second bending part 41, and the bending outside of first bending part 21 is wrapped adjacent second bending part 41.

[0031] In the embodiment, recess 221 and convex part 222 are provided on first bending part 21, the gap between the bending inside of first bending part 21 and adjacent second bending part 41 wrapped thereby is enlarged, and the gap between the bending outside of first bending part 21 and adjacent second bending part 41 wrapped thereby is also enlarged, so that more electrolyte storage space is formed between first bending part 21 and adjacent second bending part 41.The increase of electrolyte storage space can store more electrolyte, so as to improve the flowability of electrolyte in circular arc area 11, and then improve the problem of lithium precipitation in circular arc area 11 of battery without changing the size and capacity of battery.

[0032] As shown in Figure 3 And Figure 6 In some embodiments of the utility model, positive sheet 20 includes positive active material layer 24 and positive current collector 23, and positive active material layer 24 and positive current collector 23 of press area 22 are deformed as a whole to form recess 221 and convex part 222.

[0033] Specifically, positive sheet 20 in battery is composed of current collector and positive active material layer 24 on current collector.When embossing is carried out on first bending part 21 of positive sheet 20, positive active material layer 24 and current collector are deformed as a whole, recess 221 is formed on one side of current collector, and convex part 222 is formed on the opposite position, and positive active material layer 24 coated on current collector forms recess 221 or convex part 222 consistent with current collector.Specifically, the tool for embossing first bending part 21 of positive sheet 20 can be embossing roller, embossing plate and the like.

[0034] In the embodiment, the concave part 221 and the corresponding convex part 222 on the positive electrode sheet 20 are formed at one time, and the positive electrode active material layer 24 and the current collector are deformed integrally, so that the manufacturing is simple, the processing efficiency is high, and the yield is guaranteed.

[0035] In some embodiments of the present application, the length of the embossed area 22 is 2mm~10mm. That is, the length of the embossed area 22 can be any value between 2mm and 10mm, such as 2.0mm, 2.5mm, 4mm, 8mm, 10mm, etc. It should be noted that the embossing length on each first bending part 21 can be the same or different.

[0036] If the length of the embossed area 22 is too small, it is similar to not embossing the positive electrode sheet 20, and the gap between the positive electrode sheet 20 and the negative electrode sheet 40 does not change significantly. Of course, the electrolyte storage capacity of the circular arc area 11 does not increase significantly, so the lithium precipitation of the circular arc area 11 is not improved significantly. If the length of the embossed area 22 is too long, the embossed area 22 will extend to the flat area 12, increasing the gap between the positive electrode sheet 20 and the negative electrode sheet 40, thereby increasing the thickness of the battery. If the length of the embossed area 22 is too long, although the problem of lithium precipitation in the circular arc area 11 can be improved, the energy density of the battery will be reduced. The length of the embossed area 22 is set to be in the range of 2mm~10mm, which does not affect the energy density of the battery, and can effectively improve the lithium precipitation in the circular arc area 11.

[0037] In some embodiments of the present application, the length of the embossed area 22 on the first bending part 21 gradually increases from the inner layer to the outer layer along the cell structure 10.

[0038] In some embodiments of the present application, the width of the concave part 221 is 0.5mm~2.0mm. That is, the width of the concave part 221 can be any value between 0.5mm and 2.0mm, such as 0.5mm, 0.7mm, 1.0mm, 1.3mm, 1.5mm, 2.0mm, etc. It should be noted that when there are multiple concave parts 221, the width of each concave part 221 can be the same or different.

[0039] If the width of the concave part 221 is too small or too large, it will limit the storage capacity of the electrolyte, and the lithium precipitation in the circular arc area 11 will not be improved significantly. Specifically, if the width of the concave part 221 is too small, the volume of the corresponding concave part 211 is too small, and the electrolyte cannot be effectively stored. If the width of the concave part 221 is large, the number of concave parts is reduced, the transition to the flat area is simple, the electrolyte is easy to slip to the flat area, and it is not easy to store and stay in the concave part 221. In the embodiment, the width of the concave part 221 is set to a value of 0.5mm~2.0mm, which can increase the storage capacity of the electrolyte and improve the lithium precipitation in the circular arc area 11.

[0040] In some embodiments of the present application, the depth of the recess 221 is 10% to 40% of the thickness of the positive active material layer 24. That is, the depth of the recess 221 is equal to the thickness of the positive active material layer 24*(10% to 40%). Specifically, the depth of the recess 221 can be 10%, 15%, 20%, 30%, or 40% of the thickness of the positive active material layer 24, and so on.

[0041] If the depth of the recess 221 is too small, it is similar to not embossing the positive plate 20, and the gap between the positive plate 20 and the negative plate 40 does not change significantly. Of course, the storage capacity of the electrolyte in the circular arc area 11 does not increase significantly, and thus the lithium precipitation in the circular arc area 11 is not improved significantly. If the depth of the recess 221 is too long, it increases the gap between the positive plate 20 and the negative plate 40, and also significantly increases the thickness of the battery. Although it can improve the problem of lithium precipitation in the circular arc area 11, it also reduces the energy density of the battery.

[0042] In the present embodiment, the depth of the recess 221 is 10% to 40% of the thickness of the positive active material layer 24, which moderately increases the gap between the first bending part 21 and the second bending part 41, and does not significantly change the thickness of the battery. Thus, setting the depth of the recess 221 to be 10% to 40% of the thickness of the positive active material layer 24 can effectively improve the lithium precipitation in the circular arc area 11 without affecting the energy density of the battery.

[0043] In some embodiments of the present application, the distance between two adjacent recesses 221 is 0.5mm to 2.0mm. Specifically, the distance between two recesses 221 can be any value between 0.5mm and 2.0mm, such as 0.5mm, 0.7mm, 1.0mm, 1.3mm, 1.5mm, 2.0mm, and so on. It should be noted that the distance between any two adjacent recesses 221 can be equal or not equal.

[0044] If the distance between two adjacent recesses 221 is too small, the transition between the slots is natural, and the electrolyte is easily slid to the flat area and is not easy to store in the recess 221. Thus, the distance between two adjacent recesses 221 is too small to form a single slot to store electrolyte. If the distance between two adjacent recesses 221 is too large, the storage capacity of the electrolyte is limited. In the above two cases, the lithium precipitation in the circular arc area 11 is not improved significantly.

[0045] In the present embodiment, the distance between two adjacent recesses 221 is 0.5mm to 2.0mm, which is controlled within a reasonable range. It can form a single slot to store electrolyte, and also avoid that the large distance between the first bending part 21 and the second bending part 41 limits the storage capacity of the electrolyte, thereby effectively improving the lithium precipitation of the battery in the circular arc area 11.

[0046] In some embodiments of the present application, the recess 221 is in the shape of a spherical cap. In this embodiment, the recess 221 is in the shape of a spherical cap, which avoids the protrusion 222 from forming a sharp end to pierce the diaphragm 30 and damage the negative active layer on the negative plate 40.

[0047] Of course, in some other embodiments of the present application, the recess 221 can also be in the shape of a strip-shaped groove, a square pit or any other three-dimensional structure.

[0048] In some embodiments of the present application, the recesses 221 are distributed in a matrix pattern on the first bending portion 21. In this embodiment, the recesses 221 are distributed in a matrix pattern on the first bending portion 21, which facilitates the selection of the embossing tool.

[0049] The present application also provides a battery, which comprises the cell structure 10 as described in any of the above embodiments.

[0050] The present application also provides a battery module, which comprises a plurality of batteries as described in any of the above embodiments, and the plurality of batteries are connected in series.

[0051] The battery module of the present application comprises a plurality of batteries, which effectively increases the capacity of the battery module and expands the application range of the battery module. Those skilled in the art can select an appropriate number of batteries according to the application and capacity of the battery module.

[0052] The present application also provides a battery module, which comprises a plurality of batteries as described in any of the above embodiments, and the plurality of batteries are connected in parallel.

[0053] In this embodiment, the plurality of batteries are connected in parallel, which can make the battery module have a higher battery capacity, and when one battery is out of energy or fails, it does not affect the continuous power supply of other batteries in the battery module, thereby ensuring the continuous operation of the electrical equipment.

[0054] The battery module is designed according to the actual situation, so that the battery module has a more efficient energy transfer.

[0055] The above battery can be applied to any electrical equipment known in the prior art. The electrical equipment can include, but is not limited to, an electronic cigarette, an electronic vapor device, a wireless earphone, a sweeping robot, a unmanned aerial vehicle, a notebook computer, a pen input computer, a mobile computer, an electronic book player, a portable telephone, a portable facsimile machine, a portable copying machine, a portable printer, a head-mounted stereo earphone, a video recorder, a liquid crystal television, a portable cleaner, a portable CD player, a mini disc, a transceiver, an electronic organizer, a calculator, a memory card, a portable recorder, a radio, a backup power supply, a motor, a car, a motorcycle, a power-assisted bicycle, a bicycle, a lighting appliance, a toy, a game machine, a clock, a power tool, a flashlight, a camera, a household large storage battery and a lithium-ion capacitor, etc.

[0056] The battery module described above can be applied to any power consuming device known in the art.

[0057] Preferred embodiments of the present application will be described in more detail below. Although the following describes preferred embodiments of the present application, it is to be understood that the present application can be implemented in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided so that the present application will be more thoroughly and completely conveyed to those skilled in the art, and so that the scope of the present application will be fully conveyed to those skilled in the art.

[0058] Example 1, a battery:

[0059] The positive active material layer has a thickness of 35 μm, the embossed region has a length of 6 mm, the recess has a width of 1.2 mm, the recess has a depth of 30% of the thickness of the positive active material layer (10.5 μm), and the recess has a pitch of 1 mm.

[0060] Example 2, a battery:

[0061] The positive active material layer has a thickness of 35 μm, the embossed region has a length of 2 mm, the recess has a width of 0.5 mm, the recess has a depth of 30% of the thickness of the positive active material layer (10.5 μm), and the recess has a pitch of 0.5 mm.

[0062] Example 3, a battery:

[0063] The positive active material layer has a thickness of 35 μm, the embossed region has a length of 10 mm, the recess has a width of 2.0 mm, the recess has a depth of 30% of the thickness of the positive active material layer (10.5 μm), and the recess has a pitch of 2 mm.

[0064] Example 4, a battery:

[0065] The positive active material layer has a thickness of 35 μm, the embossed region has a length of 6 mm, the recess has a width of 1.2 mm, the recess has a depth of 10% of the thickness of the positive active material layer (3.5 μm), and the recess has a pitch of 1 mm.

[0066] Example 5, a battery:

[0067] The positive active material layer has a thickness of 35 μm, the embossed region has a length of 6 mm, the recess has a width of 1.2 mm, the recess has a depth of 40% of the thickness of the positive active material layer (14 μm), and the recess has a pitch of 1 mm.

[0068] Example 6, a battery:

[0069] The positive active material layer has a thickness of 35 μm, the embossed region has a length of 12 mm, the recess has a width of 1.2 mm, the recess has a depth of 30% of the thickness of the positive active material layer (10.5 μm), and the recess has a pitch of 1 mm.

[0070] Example 7, a battery:

[0071] The positive active material layer has a thickness of 35 μm, the embossed region has a length of 6 mm, the recess has a width of 0.3 mm, the recess has a depth of 30% of the thickness of the positive active material layer (10.5 μm), and the recess has a pitch of 1 mm.

[0072] Example 8, a battery:

[0073] The positive active material layer has a thickness of 35 μm, the embossed region has a length of 6 mm, the recess has a width of 3.0 mm, the recess has a depth of 30% of the thickness of the positive active material layer (10.5 μm), and the recess has a pitch of 1 mm.

[0074] Example 9, a battery:

[0075] The positive active material layer has a thickness of 35 μm, the embossed region has a length of 6 mm, the recess has a width of 1.2 mm, the recess has a depth of 45% of the thickness of the positive active material layer (16 μm), and the recess has a pitch of 1 mm.

[0076] Example 10, a battery:

[0077] The positive active material layer has a thickness of 35 μm, the embossed region has a length of 6 mm, the recess has a width of 1.2 mm, the recess has a depth of 30% of the thickness of the positive active material layer (10.5 μm), and the recess has a pitch of 0.3 mm.

[0078] Example 11, a battery:

[0079] The positive active material layer has a thickness of 35 μm, the embossed region has a length of 6 mm, the recess has a width of 1.2 mm, the recess has a depth of 30% of the thickness of the positive active material layer (10.5 μm), and the recess has a pitch of 2.5 mm.

[0080] Comparative Example 1, a battery:

[0081] The positive active material layer has a thickness of 35 μm, and the first bending portion is not provided with an embossed region.

[0082] Battery performance comparison:

[0083] Cycling performance test method: charge the battery cell to 4.5 V at 3C constant current and constant voltage, and stop charging at 0.05C. Discharge at 0.5C, after 1000 cycles, disassemble the battery to confirm the lithium precipitation in the arc region, and classify it as no lithium precipitation, slight lithium precipitation, moderate lithium precipitation, and severe lithium precipitation.

[0084] The energy density calculation method of the battery cell is: energy density = battery cell capacity * nominal voltage / battery cell height / battery cell width / battery cell thickness.

[0085] The energy density calculation and battery cell performance test were carried out on the examples 1 to 11 and the comparative example 1, and the test results are as follows:

[0086] Table 1 Battery performance test results

[0087]

[0088] Comparing the comparative example 1 and the examples 1 to 11, it can be found that the embossing of the positive plate has little effect on the energy density of the battery cell, and can improve the lithium precipitation in the arc area. Comparing the examples 7 and 8 with the examples 1 to 5, it can be seen that the width of the recess is too large or too small, which will affect the lithium precipitation in the arc area, and the width of the recess is set to 0.5mm~2.0mm, the lithium precipitation in the arc area is improved most obviously. Comparing the examples 10 and 11 with the examples 1 to 5, it can be seen that the spacing of the recess is too large or too small, which will affect the lithium precipitation in the arc area, and the spacing of the recess is set to 0.5mm~2.0mm, the lithium precipitation in the arc area is improved most obviously.

[0089] At this point, those skilled in the art should realize that, although the present application has been shown and described in detail in this paper, many other variants or modifications conforming to the principles of the present application can be directly determined or deduced according to the content disclosed in the present application without departing from the spirit and scope of the present application. Therefore, the scope of the present application should be understood and recognized as covering all these other variants or modifications.

Claims

1. A battery cell structure comprising a positive electrode, a negative electrode, and a separator, wherein the separator is used to separate the positive electrode and the negative electrode, characterized in that, The positive electrode, the negative electrode, and the separator are wound together to form a battery cell structure; The cell structure includes an arc region and a straight region; the positive electrode includes multiple first bends located in the arc region, and the negative electrode includes multiple second bends located in the arc region; the first bends are provided with embossed areas, the embossed areas having concave and convex portions, the concave portions being located inside the bend of the first bends; the convex portions being located outside the bend of the first bends.

2. The cell structure according to claim 1, characterized in that, The positive electrode sheet includes a positive electrode active material layer and a positive electrode current collector. The positive electrode active material layer and the positive electrode current collector in the embossed area are deformed as a whole to form the concave portion and the convex portion.

3. The cell structure according to claim 1, characterized in that, The length of the embossed area is 2mm to 10mm.

4. The cell structure according to claim 1, characterized in that, The width of the recess is 0.5mm to 2.0mm.

5. The cell structure according to claim 1, characterized in that, The depth of the recess is 10% to 40% of the thickness of the positive electrode active material layer.

6. The cell structure according to claim 1, characterized in that, The distance between two adjacent recesses is 0.5mm to 2.0mm.

7. The cell structure according to claim 1, characterized in that, The recess is spherical.

8. The cell structure according to claim 1, characterized in that, The recesses are distributed in a matrix pattern at the first bend.

9. A battery, characterized in that, The battery includes the cell structure as described in any one of claims 1 to 8.

10. A battery module, characterized in that, The battery module includes the battery as described in claim 9.

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