Battery cell and battery

Abstract

The battery cell comprises a plurality of pole pieces, each pole piece comprises a pole piece main body and a pole lug, the pole lug is bent and connected to one end of the pole piece main body, and the pole piece main body comprises a foil material and material layers arranged on two opposite sides of the foil material; the plurality of diaphragms and the plurality of pole pieces are alternately arranged, at least one diaphragm is provided with an insulating layer corresponding to the pole lug, and the insulating layer and the material layer are adjacently arranged or arranged at an interval. According to the structure, the insulating layer can be positioned at the top of the battery cell, and different from the arrangement of a traditional insulating layer, the condition that the material layer and the insulating layer are overlapped does not easily occur in the battery cell disclosed by the utility model. Therefore, due to the arrangement of the insulating layer, the flatness of the battery cell in the thickness direction can be ensured, and the cycle life of the battery is prolonged.

Description

TECHNICAL FIELD

[0001] The utility model relates to battery technology field especially relates to a kind of battery cell and battery. BACKGROUND

[0002] In the production process of battery cell, burr is easy to be generated on foil when tab is die-cut, and short circuit is easy to occur if burr pierces diaphragm of battery cell.For this situation, battery manufacturer usually uses inorganic filler mixed with binder as insulation material, and the insulation material is coated on the active material layer area of tab close to pole piece, so as to form insulation layer on tab, thereby avoiding burr on tab to pierce diaphragm.

[0003] In actual operation, the thickness of the region is increased due to the overlap between active material layer and insulation coating to some extent, so that the flatness of the entire battery cell in thickness direction is reduced, and the problem of uneven thickness of battery cell is generated, which may affect the overall performance of battery, such as decrease of charge-discharge efficiency and cycle life. SUMMARY

[0004] The utility model provides a kind of battery cell and battery, which can improve the problem of uneven thickness of battery cell caused by insulation layer.

[0005] In the first aspect, the utility model provides a kind of battery cell, which comprises: a plurality of pole pieces, each pole piece comprises pole piece main body and tab, the tab is bent and connected to one end of the pole piece main body, and the pole piece main body comprises foil and material layer arranged on opposite sides of the foil;A plurality of diaphragms are alternately arranged with a plurality of pole pieces, at least one diaphragm is provided with an insulation layer corresponding to the tab, and the insulation layer is adjacent to or spaced apart from the material layer.

[0006] Optionally, the plurality of pole pieces comprise a plurality of positive pole pieces, each positive pole piece comprises positive pole piece main body and positive tab;Each diaphragm comprises main body part and bending part, the main body part is arranged opposite to the pole piece main body, and the bending part is arranged opposite to the tab;The bending part of at least one diaphragm is provided with the insulation layer on the side facing the positive tab.

[0007] Optionally, the plurality of pole pieces comprise a plurality of negative pole pieces, each negative pole piece comprises negative pole piece main body and negative tab;Each diaphragm comprises main body part and bending part, the main body part is arranged opposite to the pole piece main body, and the bending part is arranged opposite to the tab;The bending part of at least one diaphragm is provided with the insulation layer on the side facing the negative tab.

[0008] Optionally, the plurality of pole pieces include a plurality of positive pole pieces and a plurality of negative pole pieces, and the positive pole pieces and the negative pole pieces are arranged alternately, and the separator is located between adjacent positive pole pieces and negative pole pieces; each positive pole piece includes a positive pole piece main body and a positive pole tab, and each negative pole piece includes a negative pole piece main body and a negative pole tab; each separator includes a main body portion and a bending portion, the main body portion is arranged opposite to the pole piece main body, and the bending portion is arranged opposite to the pole tab; at least one bending portion of the separator is provided with an insulating layer on a side facing the positive pole tab, and at least one bending portion of the separator is provided with an insulating layer on a side facing the negative pole tab.

[0009] Optionally, the plurality of pole tabs and the plurality of separators are stacked in sequence, and the length of the plurality of separators arranged along the stacking direction increases in sequence.

[0010] Optionally, the plurality of pole tabs and the plurality of separators are stacked in sequence, and along the stacking direction, the length of the separator is greater than the length of at least one of the two adjacent pole tabs.

[0011] Optionally, the plurality of pole pieces include a plurality of negative pole pieces, and each negative pole piece includes a negative pole piece main body and a negative pole tab; the negative pole piece includes a negative pole foil and a negative material layer arranged on opposite sides of the negative pole foil; and in the direction of the negative pole main body facing the negative pole tab, the end of the negative material layer protrudes from the positive material layer.

[0012] Optionally, the positive pole piece main body includes a positive pole foil and a positive material layer arranged on opposite sides of the positive pole foil; and the thickness of the insulating layer is less than or equal to the thickness of the positive material layer.

[0013] Optionally, the thickness of the insulating layer is between 8.5 microns and 25 microns.

[0014] In a second aspect, the utility model provides a kind of battery, including the battery cell as described above.

[0015] The utility model relates to battery cell including a plurality of pole pieces and a plurality of separators, wherein each pole piece includes a pole piece main body and a tab, the tab is bently connected to one end of the pole piece main body, and the pole piece main body includes a foil and a material layer arranged on opposite sides of the foil;A plurality of separators and a plurality of pole pieces are arranged alternately, at least one separator is provided with an insulating layer corresponding to the tab, and the insulating layer is adjacent to or spaced apart from the material layer. According to this structure, the separator is provided with an insulating layer, and along the height direction of the battery cell, the insulating layer can be located at the top of the battery cell, and the insulating layer is also adjacent to or spaced apart from the material layer. Unlike the traditional arrangement of the insulating layer, the battery cell in the utility model is not prone to overlap between the material layer and the insulating layer. Therefore, the arrangement of the insulating layer in the utility model can ensure the flatness of the battery cell in the thickness direction and prolong the cycle life of the battery. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] To gain a more complete understanding of this application and its beneficial effects, the following description will be provided in conjunction with the accompanying drawings, wherein the same reference numerals in the following description denote the same parts.

[0018] Figure 1 This is a schematic diagram showing the structure of the diaphragm and electrode stacking involved in this application.

[0019] Figure 2 This is a schematic diagram showing a partial structure of the separator in the battery cell involved in this application.

[0020] Figure 3 This is a partial structural schematic diagram of the positive electrode plate in the battery cell involved in this application.

[0021] Figure 4 This is a partial structural schematic diagram of the negative electrode sheet in the battery cell involved in this application.

[0022] Figure 5 This is a partial structural schematic diagram of the battery cell involved in this application.

[0023] Figure 6 This is a schematic diagram showing the structure of the diaphragm and electrode stacking involved in this application.

[0024] Reference numerals: 11, electrode body; 111, foil; 112, material layer; 12, tab; 13, positive electrode; 131, positive electrode body; 132, positive tab; 133, positive foil; 134, positive material layer; 14, negative electrode; 141, negative electrode body; 142, negative tab; 143, negative foil; 144, negative material layer; 2, separator; 21, insulating layer; 22, main body; 23, bending part. Detailed Implementation

[0025] The preferred embodiments of the present application will be described in detail below with reference to the drawings. In the following description, identical components are denoted by identical reference numerals, and repeated description will be omitted. In addition, the drawings are schematic diagrams, and the ratio of the dimensions between the components or the shape of the components, etc. can be different from the actual ones. It should be noted that all the directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present application are only used to explain the relative positional relationship, movement, etc. between the components in a certain posture, and if the certain posture changes, the directional indications will also change accordingly.

[0026] It should also be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or there can be a middle element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or there can be a middle element.

[0027] With reference to Figure 1 and Figure 2 The present application provides an electric core, which comprises a plurality of pole pieces and a plurality of separators 2. Each pole piece comprises a pole piece body 11 and a tab 12, the tab 12 being bent and connected to one end of the pole piece body 11, the pole piece body 11 comprising a foil 111 and a material layer 112 disposed on opposite sides of the foil 111; the plurality of separators 2 are alternately arranged with the plurality of pole pieces, at least one separator 2 is provided with an insulating layer 21 corresponding to the tab 12, and the insulating layer 21 is adjacent to or spaced apart from the material layer 112.

[0028] According to the above structure, in the electric core involved in the present application, the separator 2 is provided with the insulating layer 21, and along the height direction of the electric core, the insulating layer 21 can be located at the top of the electric core. Unlike the conventional arrangement of the insulating layer 21, the electric core in the present application is less likely to have the material layer 112 and the insulating layer 21 overlapping. Therefore, the arrangement of the insulating layer 21 in the present application can ensure the flatness of the electric core in the thickness direction, and the problem of uneven thickness of the electric core due to the arrangement of the insulating layer 21 is avoided, so that the battery has a higher volumetric energy density, and the cycle life of the battery is prolonged. Among them, the insulating layer 21 is adjacent to or spaced apart from the material layer 112. It can be understood that the insulating layer 21 can be located at the end of the material layer 112 and adjacent to the material layer 112. In addition, the insulating layer 21 can also be spaced apart from the material layer 112, but this spacing can be a small gap that is difficult to detect with the naked eye, and the burr of the tab 12 is usually also difficult to pass, and still can block the burr of the tab 12.

[0029] In the related art, after the pole piece and the diaphragm are alternately stacked, the diaphragm and the tab part of the pole piece are bent, and then the tab is welded. Among them, after the diaphragm and the tab are bent, the tab is usually located above the pole piece in the height direction of the battery cell, and the insulating layer on the diaphragm corresponding to the tab is also located above the pole piece. Therefore, the setting of the insulating layer will be converted into the height of the battery cell after the bending operation of the diaphragm and the tab. Therefore, the conventional setting of the insulating layer on the tab will easily cause the insulating layer to overlap the material layer, thereby increasing the thickness of the battery cell. In the present application, the insulating layer 21 is arranged on the diaphragm 2 and corresponds to the tab 12. After the diaphragm 2 and the tab 12 are bent, the insulating layer 21 is also located above the battery cell. It can be understood that the insulating layer 21 is also located above the material layer 112 in the height direction of the battery cell, so that the insulating layer 21 in the present application is not easy to overlap the material layer 112, and the setting of the insulating layer 21 only increases the height of the battery cell to a certain extent, but does not increase the thickness of the battery cell. Therefore, the setting of the insulating layer in the present application can ensure the uniform thickness of the battery cell and will not have a significant impact on the performance of the battery cell. In addition, according to the structure of the battery cell, the insulating layer 21 can be prearranged on the diaphragm 2, thereby saving the process of coating the insulating material on the tab 12, thereby simplifying the manufacturing process of the battery, which reduces the production time and reduces the production cost.

[0030] In some examples, the material of the insulating layer 21 can be polyethylene (PE), polyimide (PI), polyethylene terephthalate (PET), and epoxy resin, etc. Polyethylene has good insulation and heat resistance, polyimide is particularly suitable for use in high-temperature environments due to its excellent heat resistance and mechanical properties, and polyethylene terephthalate (PET) is widely used due to its heat resistance, chemical resistance, and mechanical properties. In addition, nanocomposites and ceramic coatings also have good insulation and heat resistance and are also suitable as insulating materials.

[0031] Referring to Figure 3 In some embodiments, the plurality of pole pieces includes a plurality of positive pole pieces 13, each positive pole piece 13 including a positive pole piece body 131 and a positive tab 132; each diaphragm 2 includes a body part 22 and a bent part 23, the body part 22 being arranged opposite to the pole piece body 11, and the bent part 23 being arranged opposite to the tab 12; and the bent part 23 of at least one diaphragm 2 is provided with an insulating layer 21 on the side facing the positive tab 132. Specifically, in the structure of the battery cell, the positive pole piece 13 is provided with a diaphragm 2 on both sides, and the positive tab 132 is wrapped by the insulating layer 21 on both sides, which can fully avoid the burrs on the positive tab 132 from piercing the diaphragm 2 and contacting the negative pole piece 14, thereby avoiding the risk of short circuit.

[0032] Referring to Figure 4In some embodiments, the plurality of pole pieces include a plurality of negative pole pieces 14, each negative pole piece 14 including a negative pole piece body 141 and a negative pole tab 142; each separator 2 includes a body portion 22 and a bent portion 23, the body portion 22 being arranged opposite to the pole piece body 11, and the bent portion 23 being arranged opposite to the pole tab 12; and the bent portion 23 of at least one separator 2 is provided with an insulating layer 21 on a side facing the negative pole tab 142. Thus, in the present embodiments, the two opposite sides of the negative pole tab 142 can also be wrapped by the insulating layer 21, so that the burrs on the negative pole tab 142 can be prevented from piercing the separator 2, and the burrs on the negative pole tab 142 can be prevented from piercing the separator 2 and contacting the positive pole piece 13, thereby avoiding the risk of short circuit.

[0033] In some embodiments, the plurality of pole pieces include a plurality of positive pole pieces 13 and a plurality of negative pole pieces 14, and the positive pole pieces 13 and the negative pole pieces 14 are arranged alternately, with the separators 2 being located between adjacent positive pole pieces 13 and negative pole pieces 14; each positive pole piece 13 includes a positive pole piece body 131 and a positive pole tab 132, and each negative pole piece 14 includes a negative pole piece body 141 and a negative pole tab 142; each separator 2 includes a body portion 22 and a bent portion 23, the body portion 22 being arranged opposite to the pole piece body 11, and the bent portion 23 being arranged opposite to the pole tab 12; and the bent portion 23 of at least one separator 2 is provided with an insulating layer 21 on a side facing the positive pole tab 132, and the bent portion 23 of at least one separator 2 is provided with an insulating layer 21 on a side facing the negative pole tab 142. Thus, in the present embodiments, the provision of the insulating layer 21 on the separator 2 can sufficiently isolate the positive pole tab 132 and also isolate the negative pole tab 142.

[0034] Referring to Figure 5 In some embodiments, the plurality of pole tabs 12 and the plurality of separators 2 are stacked in sequence, and the length of the separators 2 arranged along the stacking direction increases sequentially. Specifically, it can be understood that, in the structure of the battery cell, the length of the separators 2 located in the upper part of the battery cell increases sequentially, which is similar to a structure forming steps. In this way, the separator 2 located at the outermost side is the longest, and the length of this separator 2 located in the upper part of the battery cell can be considered to be equal to the thickness of the battery cell, i.e., the size of the corresponding insulating layer 21 can also be considered to be equal to the thickness of the battery cell. In addition, along the stacking direction, the length of the separators 2 increases sequentially, and the separators 2 are provided with the insulating layer 21 corresponding to the pole tabs 12, so it can also be understood that the length of the insulating layer 21 increases sequentially, and thus the insulating layer 21 can sufficiently isolate and wrap the pole tabs 12, and better avoid piercing by burrs.

[0035] In some embodiments, the plurality of pole tabs 12 and the plurality of separators 2 are stacked in sequence, and along the stacking direction, the length of the separators 2 is greater than the length of at least one of the two adjacent pole tabs 12. Thus, the separators 2 can better isolate the two adjacent pole tabs 12.

[0036] Referring to Figure 6In some embodiments, the plurality of pole pieces includes a plurality of negative pole pieces 14, each of which includes a negative pole piece body 141 and a negative pole tab 142; the negative pole piece 14 includes a negative pole foil 143 and a negative pole material layer 144 arranged on opposite sides of the negative pole foil 143; in the direction from the negative pole body to the negative pole tab 142, the end of the negative pole material layer 144 protrudes beyond the positive pole material layer 134. Thus, the negative pole material layer 144 can be considered to form a wrapped structure with the positive pole material layer 134. In the related art, the outermost side of the battery cell is usually the negative pole piece 14, and the material layer 112 of the negative pole piece 14 is usually graphite material. Specifically, during the use of the battery, the number of charge and discharge cycles is a key indicator of its service life. The stability of graphite ensures that the performance of the battery decreases less after multiple cycles, prolonging the service life of the battery. In addition to cycle stability, graphite, as a very stable material, plays a crucial role in battery technology. Its unique crystal structure and chemical properties endow graphite with the ability to remain stable during charging and discharging. During the charging and discharging process of the battery, heat is generated due to the flow of current and chemical reactions. Graphite has good thermal stability and is not prone to thermal runaway, which means that when the temperature of the battery rises, graphite will not decompose rapidly or produce toxic gases, thereby reducing the safety risk of the battery in high-temperature environments. The thermal stability of graphite also means that when the battery overheats, graphite can withstand a certain temperature without losing its structural integrity, which helps to prevent performance degradation or damage to the battery due to overheating. Therefore, the structure in which the end of the negative pole material layer 144 protrudes beyond the positive pole material layer 134 forms a wrapped structure around the positive pole material layer 134, which can improve the service life and safety performance of the battery.

[0037] In some embodiments, the positive pole piece body 131 includes a positive pole foil 133 and a positive pole material layer 134 arranged on opposite sides of the positive pole foil 133; the thickness of the insulating layer 21 is less than or equal to the thickness of the positive pole material layer 134. Specifically, the thickness of the battery cell can be less than the thickness of the positive pole material layer 134, thereby saving materials and avoiding the problem of excessive height of the battery cell due to the thickness of the insulating layer 21 being too thick after folding. Of course, the thickness of the insulating layer 21 can be the same as the thickness of the positive pole material layer 134, but considering the height of the battery cell and the cost of production, it is not advisable to set the insulating layer 21 to be thicker than the positive pole material layer 134.

[0038] In some embodiments, the thickness of the insulation layer 21 is between 8.5 microns and 25 microns. In this way, the thickness of the insulation layer 21 is controlled to be between 8.5 microns and 25 microns, which takes into account both cost control and excellent insulation performance and puncture resistance. A thinner insulation layer 21 helps to reduce the weight of the battery and reduce costs, while a thicker insulation layer 21 provides more reliable protection against the positive tab 132 burr puncturing the separator 2, ensuring safe operation of the battery. The staff can choose the appropriate thickness of the insulation layer 21 according to the actual needs.

[0039] The application also provides a battery comprising the battery cell as described above.

[0040] In summary, in the battery cell involved in the present application, the insulation layer 21 can be located at the top of the battery cell. Unlike the conventional arrangement of the insulation layer 21, the battery cell in the present application is less likely to have the material layer 112 overlapping the insulation layer 21. In this way, the arrangement of the insulation layer 21 in the present application can ensure the flatness of the battery cell in the thickness direction, and the problem of uneven thickness of the battery cell due to the arrangement of the insulation layer 21 can be avoided, so that the charging and discharging efficiency of the battery is higher, and the cycle life of the battery is prolonged.

[0041] In the description of the present application, the terms "first", "second" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first", "second" can explicitly or implicitly include one or more features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise specifically limited.

[0042] In the above embodiments, the description of each embodiment has its own emphasis, and the parts not described in detail in a certain embodiment can be referred to the related description of other embodiments.

[0043] The embodiments, implementation manners and related technical features of the present application can be combined, replaced with each other without conflict.

[0044] The above is only a preferred embodiment of the present application, and does not limit the present application in any form. Any simple modification, equivalent change and modification made to the above embodiment according to the technical essence of the present application without departing from the technical solution of the present application, all still fall within the scope of the technical solution of the present application.

[0045] Although the present application has been specifically described above in combination with the drawings and embodiments, it should be understood that the above description does not limit the present application in any form. Those skilled in the art can make modifications and changes to the present application according to needs without departing from the essential spirit and scope of the present application, and these modifications and changes all fall within the scope of the present application.

Claims

1. An electric cell, characterized by, The application relates to a battery cell, comprising: a plurality of pole pieces, each of the pole pieces comprising a pole piece body and a pole tab, the pole tab being connected to one end of the pole piece body by bending, the pole piece body comprising a foil and material layers arranged on opposite sides of the foil; a plurality of diaphragms, the plurality of diaphragms and the plurality of pole pieces being arranged alternately, at least one of the diaphragms being provided with an insulating layer corresponding to the pole tab, and the insulating layer being arranged adjacently or spacedly with the material layer.

2. The electric cell of claim 1, wherein, The plurality of pole pieces comprises a plurality of positive pole pieces, each of the positive pole pieces comprising a positive pole piece body and a positive pole tab. Each of the diaphragms comprises a body part and a bending part, the body part being arranged oppositely to the pole piece body, and the bending part being arranged oppositely to the pole tab. The bending part of at least one of the diaphragms is provided with the insulating layer on a side facing the positive pole tab.

3. The electric cell of claim 1, wherein, The plurality of pole pieces comprises a plurality of negative pole pieces, each of the negative pole pieces comprising a negative pole piece body and a negative pole tab. Each of the diaphragms comprises a body part and a bending part, the body part being arranged oppositely to the pole piece body, and the bending part being arranged oppositely to the pole tab. The bending part of at least one of the diaphragms is provided with the insulating layer on a side facing the negative pole tab.

4. The electric cell of claim 1, wherein, The plurality of pole pieces comprises a plurality of positive pole pieces and a plurality of negative pole pieces, and the positive pole pieces and the negative pole pieces are arranged alternately, and the diaphragm is arranged between adjacent positive pole pieces and negative pole pieces. Each of the positive pole pieces comprises a positive pole piece body and a positive pole tab, and each of the negative pole pieces comprises a negative pole piece body and a negative pole tab. Each of the diaphragms comprises a body part and a bending part, the body part being arranged oppositely to the pole piece body, and the bending part being arranged oppositely to the pole tab. The bending part of at least one of the diaphragms is provided with the insulating layer on a side facing the positive pole tab, and the bending part of at least one of the diaphragms is provided with the insulating layer on a side facing the negative pole tab.

5. The electric cell of any one of claims 1-4, wherein, The plurality of pole tabs and the plurality of diaphragms are arranged in sequence, and the lengths of the plurality of diaphragms arranged in the sequence increase in sequence.

6. The electric cell of any one of claims 1-4, wherein, The plurality of pole tabs and the plurality of diaphragms are arranged in sequence, and along the sequence arrangement direction, the length of the diaphragm is greater than the length of at least one of the two adjacent pole tabs.

7. The electric cell of claim 1, wherein, The plurality of pole pieces comprises a plurality of negative pole pieces, each of the negative pole pieces comprising a negative pole piece body and a negative pole tab. The negative pole piece comprises a negative foil and negative material layers arranged on opposite sides of the negative foil. The plurality of pole pieces further comprises a plurality of positive pole pieces, each of the positive pole pieces comprising a positive pole piece body and a positive pole tab. The positive pole piece body comprises a positive foil and positive material layers arranged on opposite sides of the positive foil. In the direction of the negative pole tab facing the negative pole piece body, the end of the negative material layer protrudes from the positive material layer.

8. The cell of claim 2 or 4, wherein, The positive pole piece body comprises a positive foil and positive material layers arranged on opposite sides of the positive foil. The thickness of the insulating layer is less than or equal to the thickness of the positive material layer.

9. The electric cell of any one of claims 1-4, wherein, The thickness of the insulating layer is between 8.5 microns and 25 microns.

10. A battery, characterized by The application further relates to a battery comprising the battery cell as claimed in any one of claims 1 to 9.

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