Battery cell and lithium ion battery

Abstract

The utility model discloses a battery cell and lithium ion battery, the battery cell comprises a first roll core and a second roll core, the first roll core takes the shape of a regular polygon, the second roll core takes the shape of a cylinder, and a regular prism-shaped through hole of the first roll core is tangent to the second roll core. A gap between the shell and the first roll core is filled, and only a gap exists between the first roll core and the second roll core. In other words, a larger gap between the shell in the shape of a regular polygon and the cylindrical battery core is changed into a smaller gap between the regular prism-shaped through hole of the first roll core and the second roll core, so that the space utilization rate of the lithium ion battery is improved, and the energy density of the lithium ion battery is further improved.

Description

Technical Field

[0001] The utility model relates to the technical field of lithium ion batteries, in particular to a battery core and a lithium ion battery. Background Art

[0002] At present, most single cells are cylindrical in structure. When a large number of cylindrical single cells are combined to form a module, the gap between two adjacent cylindrical single cells is large, which makes the mechanical stability of the module very poor and prone to short circuit or open circuit when subjected to external vibration or impact.

[0003] To address this issue, the traditional solution is to design lithium-ion batteries into a regular polygonal shape, using cylindrical cells that are inscribed within the regular polygonal casing. However, there is still a large gap between the inscribed cylindrical cells and the regular polygonal casing, resulting in low space utilization and a low battery energy density. Utility Model Content

[0004] The main purpose of the utility model is to provide a battery core, aiming to solve the problem of low space utilization of existing regular polygonal lithium-ion batteries.

[0005] To achieve the above-mentioned object, the present invention provides a battery cell for use in a regular polygonal lithium-ion battery, the battery cell comprising:

[0006] a first winding core, wherein the first winding core is in the shape of a regular prism, a regular prism-shaped through-hole is formed through the first winding core, and an outer wall of the first winding core is in contact with an inner wall of the outer shell of the lithium-ion battery;

[0007] a second winding core, the second winding core being cylindrical and disposed in the first regular prism-shaped through hole;

[0008] The inner sidewall of the regular prism-shaped through hole includes a plurality of first edge faces connected end to end in sequence, and the outer sidewall of the second winding core is inscribed in the plurality of first edge faces.

[0009] In some embodiments, the first winding core is in the shape of a regular hexagonal prism, and the regular prism-shaped through hole is in the shape of a regular hexagonal prism.

[0010] In some embodiments, the side length b of the opening of the first edge face is greater than or equal to 10 mm.

[0011] In some embodiments, the radius r of the second winding core and the side length b of the first edge face satisfy the following relationship: 0.6b≤r≤0.866b.

[0012] The present application also discloses a lithium-ion battery, comprising a housing and the battery cell described in the aforementioned embodiment;

[0013] Wherein, a cavity is constructed in the shell, and the cavity is in the shape of a regular polygonal prism;

[0014] The battery core is disposed in the cavity, and the outer sidewall of the battery core is in contact with the inner sidewall of the cavity.

[0015] In some embodiments, the first winding core is provided with a first positive electrode tab and a first negative electrode tab, the second winding core is provided with a second positive electrode tab and a second negative electrode tab, the first positive electrode tab is connected to the second positive electrode tab, and the first negative electrode tab is connected to the second negative electrode tab.

[0016] In some embodiments, the first winding core includes a first positive electrode sheet, a first separator, and a first negative electrode sheet, the first separator is disposed between the first positive electrode sheet and the first negative electrode sheet, the first positive electrode tab is connected to the first positive electrode sheet, and the first negative electrode tab is connected to the first negative electrode sheet; and / or,

[0017] The second winding core includes a second positive electrode sheet, a second separator and a second negative electrode sheet, the second separator is arranged between the second positive electrode sheet and the second negative electrode sheet, the second positive electrode tab is connected to the second positive electrode sheet, and the second negative electrode tab is connected to the second negative electrode sheet.

[0018] In some embodiments, the housing includes a bottom shell and a cover plate, and the cover plate is welded to the bottom shell.

[0019] In some embodiments, a liquid injection hole is configured on the cover plate.

[0020] In some embodiments, the cover plate is connected to the positive electrodes of the first and second winding cores, and the bottom shell is connected to the negative electrodes of the first and second winding cores.

[0021] The utility model discloses a battery cell comprising a first winding core and a second winding core, wherein the first winding core is in the shape of a regular polygon and the second winding core is in the shape of a cylinder. The regular prismatic through-hole of the first winding core is tangent to the second winding core. Because the outer wall can be tightly attached to the outer shell of the regular polygon-shaped lithium-ion battery, the gap between the outer shell and the first winding core is filled, and only a gap exists between the first and second winding cores. In other words, the utility model transforms the larger gap between the regular polygon-shaped outer shell and the cylindrical battery cell into a smaller gap between the regular prismatic through-hole of the first winding core and the second winding core, thereby improving the space utilization of the lithium-ion battery and thereby increasing the energy density of the lithium-ion battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic structural diagram of a hexagonal lithium-ion battery in the prior art;

[0023] Figure 2This is a cross-sectional view of an embodiment of a lithium-ion battery of the present invention;

[0024] Figure 3 A top view of another embodiment of the lithium-ion battery of the present invention;

[0025] Figure 4 This is a top view of the cover plate in the lithium-ion battery of the present invention.

[0026] Reference numerals:

[0027] 100, first winding core; 110, regular prism-shaped through hole; 200, second winding core; 300, outer shell; 310, bottom shell; 320, cover plate; 321, liquid injection hole. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the schemes in the embodiments of the present invention. Obviously, the embodiments described are only 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 making creative efforts are within the scope of protection of the present invention.

[0029] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0030] It should also be noted that when an element is referred to as being "fixed on" or "disposed on" another element, it may be directly on the other element or there may be an intermediate element. When an element is referred to as being "connected to" another element, it may be directly connected to the other element or there may be an intermediate element.

[0031] In addition, the descriptions of "first," "second," etc. in this utility model are for descriptive purposes only and should not be understood as indicating or implying their relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of such features. In addition, the technical solutions between the various embodiments can be combined with each other, but this must be based on the fact that they can be implemented by ordinary technicians in this field. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by this utility model.

[0032] Figure 1This is the structure of a hexagonal lithium-ion battery in the prior art, in which a cylindrical battery core is inscribed in a hexagonal shell.

[0033] The utility model provides a battery cell, which is applied to a regular polygonal lithium-ion battery. Figure 2 , the battery cell includes:

[0034] The first winding core 100 is in the shape of a regular prism. A regular prism-shaped through hole 110 is formed through the first winding core 100. The outer wall of the first winding core 100 is in contact with the inner wall of the outer shell 300 of the lithium-ion battery.

[0035] The second winding core 200 is cylindrical and is disposed in the first regular prism-shaped through hole 110;

[0036] The inner sidewall of the regular prism-shaped through hole 110 includes a plurality of first edge faces connected end to end in sequence, and the outer sidewall of the second winding core 200 is inscribed in the plurality of first edge faces.

[0037] The shapes of the first winding core 100 and the regular prismatic through-hole 110 can be determined as needed, typically depending on the shape of the desired lithium-ion battery. For example, if the desired lithium-ion battery is a regular triangular prism, the first winding core 100 and the regular prismatic through-hole 110 should also be regular triangular prisms. As will be appreciated, since the winding core is formed by winding the positive electrode sheet, separator, and negative electrode sheet using a winding needle, the first winding core 100 and the regular prismatic through-hole 110 are coaxially arranged and have the same shape.

[0038] The second winding core 200 is a cylindrical battery cell, and the outer wall of the second winding core 200 is tangent to the first edge surface of the regular prismatic through hole 110 to minimize the gap between the second winding core 200 and the first winding core 100. Therefore, the radius of the second winding core 200 is related to the side length of the opening of the first edge surface of the regular prismatic through hole 110. For example, when the regular prismatic through-hole 110 is in the shape of a triangular prism, the radius of the second winding core 200 is the radius of the inscribed circle of an equilateral triangle, where the side length of the equilateral triangle is the side length of the opening of the first facet. The calculation process is relatively simple and is not expanded in this embodiment. The result is that the radius of the second winding core 200 is approximately 0.29 times the side length of the opening of the first facet. The solution in this embodiment converts the larger triangular prism inscribed in the larger cylinder into a smaller triangular prism inscribed in the smaller cylinder. When calculating, it can be regarded as reducing the structure of the prior art by a certain proportion. Therefore, it can be undoubtedly concluded that the gap left when the converted triangular prism and cylinder are inscribed is smaller. It can be understood that when the regular prismatic through-hole 110 is of other shapes, the same is true and will not be repeated here.

[0039] The present invention improves the space utilization rate in the lithium-ion battery by converting the gap between the larger regular polygon-shaped shell 300 and the cylindrical battery core into a smaller gap between the regular prismatic through hole 110 of the first winding core 100 and the second winding core 200, thereby improving the energy density of the lithium-ion battery.

[0040] like Figure 2 As shown, in some embodiments, the first winding core 100 is in the shape of a regular hexagonal prism, and the regular prism-shaped through hole 110 is in the shape of a regular hexagonal prism.

[0041] The shape of the first winding core 100 is determined according to the shape of the lithium-ion battery, which is usually in the shape of a hexagonal prism. This is because regular hexagonal prisms can be closely arranged in a certain space to reduce gaps, thereby improving space utilization, which is very important for applications that require high energy density, such as energy storage systems for electric vehicles. In addition, hexagonal structures are considered to have high strength and stability due to their unique geometric properties in nature and engineering. For example, honeycomb structures use regular hexagonal units to provide extremely high strength and toughness. Therefore, in this embodiment, the first winding core 100 is set to the shape of a regular hexagonal prism to better fit the outer shell 300 of the lithium-ion battery.

[0042] like Figure 3 As shown, in some embodiments, the side length b of the opening of the first edge facet is greater than or equal to 10 mm.

[0043] In this embodiment, the first winding core 100 is in the shape of a hexagonal prism, which usually needs to be wound using a hexagonal winding needle. If the side length of the hexagonal winding needle is too small, the shape of the first winding core 100 will easily distort towards the cylindrical winding core during the winding process, resulting in an inability to fit the hexagonal lithium-ion battery shell 300. This is also the reason why it is impossible to fill the interior of a hexagonal lithium-ion battery with only a hexagonal winding core. If the side length of the hexagonal winding needle is too large, the wound core will have a large hole in the middle. Therefore, in this embodiment, the side length b of the first edge face in the first winding core 100 is controlled to be greater than or equal to 10 mm to ensure that the first winding core 100 can still maintain a regular hexagonal prism shape during the winding process.

[0044] like Figure 3 As shown, in some embodiments, the radius r of the second winding core 200 and the side length b of the first edge face satisfy the following relationship: 0.6b≤r≤0.866b.

[0045] In this embodiment, the first winding core 100 is in the shape of a hexagonal prism, and the regular prism-shaped through-hole 110 is also in the shape of a regular hexagonal prism. When r = 0.866b, the outer wall of the second winding core 200 is exactly inscribed with the inner wall of the regular prism-shaped through-hole 110, and the blank area left at this time is minimized. However, in the actual preparation of the second winding core 200, considering the errors in the manufacturing process and to enable the second winding core 200 to be easily inserted into the regular prism-shaped through-hole 110 of the first winding core 100, the radius r of the second winding core 200 is limited to between 0.6b and 0.866b. If r is less than 0.6b, the effect of improving space utilization of the present application solution will be weakened. If r is greater than 0.866b, it is easy for the second winding core 200 to be unable to be placed in the regular prism-shaped through-hole 110, resulting in the second winding core 200 being unusable.

[0046] like Figure 2 and Figure 3 As shown, the present invention further proposes a lithium-ion battery comprising a housing 300 and a cell. The specific structure of the cell is similar to the above-mentioned embodiment. Since the lithium-ion battery adopts all the technical solutions of all the above-mentioned embodiments, it has at least all the technical effects brought about by the technical solutions of the above-mentioned embodiments, and no further description is given here. Specifically, a cavity is constructed within the housing 300, and the cavity is in the shape of a regular polygonal prism.

[0047] The battery cell is placed in the cavity, with the outer wall of the battery cell conforming to the inner wall of the cavity. The outer wall of the first winding core 100 in the battery cell is closely attached to the inner wall of the cavity, and the outer wall of the second winding core 200 is tangent to the inner wall of the regular prismatic through-hole 110 in the first winding core 100. This transforms the larger gap between the regular polygon-shaped outer shell 300 and the cylindrical battery cell into a smaller gap between the regular prismatic through-hole 110 of the first winding core 100 and the second winding core 200. This improves the space utilization within the lithium-ion battery, thereby increasing the energy density of the lithium-ion battery.

[0048] In some embodiments, the first winding core 100 is provided with a first positive electrode tab and a first negative electrode tab, and the second winding core 200 is provided with a second positive electrode tab and a second negative electrode tab, the first positive electrode tab is connected to the second positive electrode tab, and the first negative electrode tab is connected to the second negative electrode tab.

[0049] Taking the hexagonal first winding core 100 as an example, first, the hexagonal rigid object is inserted into the hexagonal regular prism through hole 110 and hot pressed on six sides to fix the shape structure of the first winding core 100, and then the first positive pole ear and the first negative pole ear are led out on both sides of the first winding core 100 respectively; the second positive pole ear and the second negative pole ear are led out on both sides of the second winding core 200 respectively; then the second winding core 200 is inserted into the regular prism through hole 110, and the first positive pole ear and the second positive pole ear are on the same side, and the first negative pole ear and the second negative pole ear are on the same side, the pole ears on the same side are welded together and led out, and the setting of the pole ears on the battery cell is completed.

[0050] The battery cell in this embodiment is split into a first winding core 100 and a second winding core 200. According to the law of resistance, the resistance is inversely proportional to the length of the material. Therefore, the resistance values of the first winding core 100 and the second winding core 200 are both smaller than the resistance value of the single cylindrical battery cell used in the prior art; and the tabs of the split first winding core 100 and the second winding core 200 are led out after being welded in parallel, so that the first winding core 100 and the second winding core 200 form a parallel structure, which further reduces the internal resistance of the lithium-ion battery and enables the lithium-ion battery to exert higher power performance.

[0051] In some embodiments, the first winding core 100 includes a first positive electrode sheet, a first separator, and a first negative electrode sheet, the first separator is disposed between the first positive electrode sheet and the first negative electrode sheet, the first positive electrode tab is connected to the first positive electrode sheet, and the first negative electrode tab is connected to the first negative electrode sheet; and / or,

[0052] The second winding core 200 includes a second positive electrode sheet, a second separator and a second negative electrode sheet. The second separator is arranged between the second positive electrode sheet and the second negative electrode sheet. The second positive electrode tab is connected to the second positive electrode sheet, and the second negative electrode tab is connected to the second negative electrode sheet.

[0053] like Figure 2 As shown, in some embodiments, the housing 300 includes a bottom housing 310 and a cover plate 320, which is welded to the bottom housing 310. The bottom housing 310 and the cover plate 320 define a cavity for accommodating the battery cell. During fabrication, the battery cell is first placed within the bottom housing 310, and the cover plate 320 is then placed over the opening of the bottom housing 310 and welded to seal the cavity.

[0054] like Figure 4 As shown, in some embodiments, the cover plate 320 is configured with an injection hole 321. The injection hole 321 can connect the cavity with the external environment, facilitating the injection of electrolyte into the cavity. It is understood that after the electrolyte is injected, the injection hole 321 must be sealed with a sealing structure such as a sealing pin to prevent leakage of the electrolyte.

[0055] In some embodiments, the cover plate 320 is connected to the positive electrodes of the first and second winding cores 100 and 200, and the bottom shell 310 is connected to the negative electrodes of the first and second winding cores 100 and 200. The resulting lithium-ion battery uses the cover plate 320 as the positive electrode and the bottom shell 310 as the negative electrode, making it easy to connect to external electrical appliances.

[0056] The above description is only part or preferred embodiments of the present invention. Neither the text nor the drawings can limit the scope of protection of the present invention. All equivalent structural transformations made by using the contents of the present invention specification and drawings under the overall concept of the present invention, or direct / indirect application in other related technical fields are included in the scope of protection of the present invention.

Claims

1. A battery cell, used in lithium-ion batteries, characterized in that: include: a first winding core, wherein the first winding core is in the shape of a regular prism, a regular prism-shaped through-hole is formed through the first winding core, and an outer wall of the first winding core is in contact with an inner wall of the outer shell of the lithium-ion battery; a second winding core, the second winding core being cylindrical and disposed in the regular prism-shaped through hole; The inner sidewall of the regular prism-shaped through hole includes a plurality of first edge faces connected end to end in sequence, and the outer sidewall of the second winding core is inscribed in the plurality of first edge faces.

2. The battery cell according to claim 1, characterized in that The first winding core is in the shape of a regular hexagonal prism, and the regular prism-shaped through hole is in the shape of a regular hexagonal prism.

3. The battery cell according to claim 2, characterized in that The side length b of the opening of the first edge face is greater than or equal to 10 mm.

4. The battery cell according to claim 3, characterized in that The radius r of the second winding core and the side length b of the first edge face satisfy the following relationship: 0.6b≤r≤0.866b.

5. A lithium-ion battery, characterized in that: A battery comprising a housing and a battery cell according to any one of claims 1 to 4; Wherein, a cavity is constructed in the shell, and the cavity is in the shape of a regular polygonal prism; The battery core is disposed in the cavity, and the outer sidewall of the battery core is in contact with the inner sidewall of the cavity.

6. The lithium-ion battery according to claim 5, characterized in that The first winding core is provided with a first positive electrode tab and a first negative electrode tab, and the second winding core is provided with a second positive electrode tab and a second negative electrode tab. The first positive electrode tab is connected to the second positive electrode tab, and the first negative electrode tab is connected to the second negative electrode tab.

7. The lithium-ion battery according to claim 6, characterized in that The first winding core includes a first positive electrode sheet, a first separator and a first negative electrode sheet, the first separator is arranged between the first positive electrode sheet and the first negative electrode sheet, the first positive electrode tab is connected to the first positive electrode sheet, and the first negative electrode tab is connected to the first negative electrode sheet; and / or, The second winding core includes a second positive electrode sheet, a second separator and a second negative electrode sheet, the second separator is arranged between the second positive electrode sheet and the second negative electrode sheet, the second positive electrode tab is connected to the second positive electrode sheet, and the second negative electrode tab is connected to the second negative electrode sheet.

8. The lithium-ion battery according to claim 6 or 7, characterized in that The housing includes a bottom shell and a cover plate, and the cover plate is welded to the bottom shell.

9. The lithium-ion battery according to claim 8, characterized in that A liquid injection hole is configured on the cover plate.

10. The lithium-ion battery according to claim 9, characterized in that The cover plate is connected to the positive electrodes of the first and second winding cores, and the bottom shell is connected to the negative electrodes of the first and second winding cores.

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