CN218447965U - Sodium ion battery negative plate with low surface density and sodium ion battery - Google Patents
Sodium ion battery negative plate with low surface density and sodium ion battery Download PDFInfo
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- CN218447965U CN218447965U CN202222407623.3U CN202222407623U CN218447965U CN 218447965 U CN218447965 U CN 218447965U CN 202222407623 U CN202222407623 U CN 202222407623U CN 218447965 U CN218447965 U CN 218447965U
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- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
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- Y02E60/10—Energy storage using batteries
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Abstract
The utility model discloses a sodium ion battery negative pole piece of low areal density, including with regard to the fluid, the mass flow body includes negative and positive, and the negative and positive of the mass flow body all coats and have sodium ion battery negative material layer, and thickness H after this negative pole piece coating satisfies following relation: h = D/(P + K) 10000 + 2+ C; wherein D is the single-sided areal density and the unit is g/m 2 (ii) a P is the powder tap density of the negative electrode material, and the unit isg/cm 3 (ii) a K is an adjusting coefficient, the value of K is 0.15-0.25, and the unit is g/cm 3 (ii) a And C is the thickness of a current collector and has a unit of μm. The utility model discloses a sodium ion battery negative pole piece of low surface density has that production efficiency is high, the thickness uniformity is good and the characteristics that the pole piece outward appearance is good.
Description
Technical Field
The utility model relates to a sodium ion battery technical field specifically indicates a sodium ion battery negative pole piece and sodium ion battery of low areal density.
Background
The sodium ion battery and the lithium ion battery are similar in battery cell design and manufacturing process, and the development process comprises the following processes: design → \ 8230; \ 8230; → coating → \8230; → assembly. The gram capacity of the common cathode raw material is lithium cobaltate (150-190 mAh.g) -1 ) Ternary (155-200 mAh. G) -1 ) Lithium iron phosphate (150 mAh. G) -1 About), the negative electrode material was graphite (350 mAh · g) -1 Left and right). In the design stage of the lithium ion battery, the actual N/P ratio (negative electrode capacity per unit area divided by positive electrode capacity) is generally between 1.08 and 1.15 according to the first efficiency of raw materials and considering the engineering capability. Taking the case that the positive electrode is lithium iron phosphate, the negative electrode is graphite, and the N/P ratio is designed to be 1.10, the following facts are considered: (1) the gram capacity of the negative electrode/gram capacity of the positive electrode is approximately equal to 2.33; (2) in the positive and negative electrodes, the loading of active material is close. For convenience of description, if the positive and negative electrode loading amounts are equal, R = negative electrode area density/positive electrode area density ≈ 0.47. The designed surface density of the lithium iron phosphate electrode generally falls between 150 and 200g/m 2 In the interval, the corresponding surface density of the graphite negative electrode is 70.5-94.0 g/m 2 An interval.
For a sodium ion battery in which the positive electrode material is a polyanion, the gram capacity of the positive electrode active material is 100mAh · g -1 About (90-110 mAh g) -1 ) The gram capacity of the hard carbon cathode is 340-400 mAh.g -1 Taking the design of an N/P ratio of 1.10 as an example, consider the following facts: (1) the gram capacity of the negative electrode/gram capacity of the positive electrode is approximately equal to 3.4-4.0; (2) in the positive and negative electrodes, the amounts of the active material are close (for convenience, the amounts of the positive and negative electrodes are equal), and R = negative electrode area density/positive electrode area density ≈ 0.275 to 0.324. When the R value is too small, the surface density of the positive electrode is in a reasonable range (such as 100-200 g/m) 2 ) The surface density of the negative electrode was too low (corresponding to 27.5 to 64.8 g/m) 2 )，The design surface density is too small, and the coating is easy to cause the abnormalities such as scratches and particles, so that the production continuity is affected, and the consistency of the pole piece is poor.
SUMMERY OF THE UTILITY MODEL
The utility model aims at providing a sodium ion battery negative pole piece and sodium ion battery of low surface density has that production efficiency is high, the thickness uniformity is good and the characteristics that the pole piece outward appearance is good.
The utility model discloses can realize through following technical scheme:
the utility model discloses a sodium ion battery negative pole piece of low areal density, including with regard to the fluid, the mass flow body includes negative and positive faces, and the negative and positive faces of the mass flow body have all coated sodium ion battery negative material layer, and thickness H after this negative pole piece coating satisfies following relation: h = D/(P + K) 10000 + 2+ C; wherein D is the single-sided areal density and the unit is g/m 2 (ii) a P is the tap density of the powder of the negative electrode material and has a unit of g/cm 3 (ii) a K is an adjusting coefficient, the value of K is 0.15-0.25, and the unit is g/cm 3 (ii) a And C is the thickness of the current collector and has a unit of μm.
Further, the thickness h of the wet film in the cathode sheet coating process satisfies the following relation: h = (H-C)/2/S; wherein h is the thickness of the single-sided wet film, and S is the solid content of the slurry.
Further, the negative electrode material layer of the sodium-ion battery is a hard carbon material layer.
Further, the minimum particle size D0 of the hard carbon material is more than or equal to 0.5um.
Further, the current collector is an aluminum foil, and the aluminum foil is a single-sided aluminum wool foil or a double-sided aluminum wool foil.
Further, the thickness of the current collector is 2-20 μm; the thickness of one side of the dried non-rolled negative electrode material layer of the sodium ion battery is 40-90 mu m.
Further, the thicknesses of the negative electrode material layers of the sodium ion battery coated on the negative surface and the positive surface of the current collector are the same or different.
Furthermore, the single-side surface density of the negative electrode material layer of the sodium ion battery is 25-75 g/m 2 。
Further, a conductive adhesive layer is coated between the sodium ion battery negative electrode material layer and the current collector.
Another aspect of the present invention is to protect the sodium ion battery, which is formed by winding or laminating the above-mentioned low surface density negative electrode plate of the sodium ion battery.
The utility model relates to a sodium ion battery negative pole piece and sodium ion battery of low surface density has following beneficial effect:
firstly, the production efficiency is high, and by adopting the thickness control scheme of the utility model, large particles are prevented from blocking the knife edge and the slit, the coating smoothness is ensured, and the continuous production is effectively realized;
secondly, the thickness consistency is good, and by adopting the thickness control scheme of the utility model, the knife edge and the slit are prevented from being blocked by large particles, the machine does not need to be stopped and debugged frequently, and the uniformity and consistency of the coating thickness are effectively ensured;
thirdly, the appearance of the pole piece is good, and by adopting the thickness control scheme of the utility model, the small particles are prevented from agglomerating due to large surface energy, and scratches and granular feeling are avoided; meanwhile, the carbon black powder conductive agent is prevented from agglomerating due to huge surface energy to form scratches and granular feeling.
Drawings
Fig. 1 is a schematic structural diagram of a low surface density negative plate of a sodium ion battery of the present invention;
fig. 2 is a schematic structural diagram of another embodiment of the low-surface-density negative plate of the sodium-ion battery of the present invention;
the reference numbers in the drawings include: 100. a current collector; 200. a female side; 300. sunny side; 4. a conductive adhesive layer; 500. and the negative electrode material layer.
Detailed Description
In order to make those skilled in the art better understand the technical solution of the present invention, the following provides a detailed description of the product of the present invention with reference to the embodiments and the accompanying drawings.
As shown in figure 1, the utility model discloses a sodium ion battery negative plate with low surface density, which comprises a fluid, a current collector 100 comprising a negative surface 200 and a positive surface 300, and a negative surface 200 and a positive surface 300 of the current collectorThe positive surfaces 300 are all coated with a sodium ion battery negative electrode material layer 500, and the thickness H of the negative electrode sheet after coating satisfies the following relation: h = D/(P + K) 10000 + 2+ C; wherein D is the single-sided surface density and the unit is g/m 2 (ii) a P is the powder tap density of the negative electrode material and has the unit of g/cm 3 (ii) a K is an adjusting coefficient, the value of K is 0.15-0.25, and the unit is g/cm 3 (ii) a And C is the thickness of the current collector and has a unit of μm.
In actual production, the thickness H of the negative pole piece after coating fluctuates by +/-10 μm on the basis of the calculation result in consideration of the rough surface of the pole piece after coating and drying.
In order to facilitate process control, the thickness h of the wet film in the coating process of the negative plate meets the following relational expression: h = (H-C)/2/S; wherein h is the thickness of the single-sided wet film, and S is the solid content of the slurry.
In actual production, in order to effectively ensure the appearance of the pole piece, the negative electrode material layer of the sodium-ion battery is a hard carbon material layer. Specifically, the minimum particle diameter D0 of the hard carbon material is more than or equal to 0.5um. The nano-scale particles have larger surface energy and can be rapidly agglomerated into micron-scale large particles, so that the particle size of the smallest particles is controlled to be 50 percent of the micron-scale.
In actual production, the selection of the current collector is flexible, the current collector is an aluminum foil, and the aluminum foil is a single-side aluminum foil or a double-side aluminum foil.
In the aspect of thickness control, the thickness of the current collector is 2-20 mu m; the thickness of one side of the dried non-rolled negative electrode material layer of the sodium ion battery is 40-90 mu m. Meets the requirements of the current mainstream battery process equipment.
In the design and processing process of the pole piece, the thicknesses of the negative electrode material layers of the sodium ion battery coated on the negative surface and the positive surface of the current collector are the same or different, so that the flexibility is high, and the product design is convenient.
The utility model discloses in, in order to effectively regulate and control the pole piece outward appearance, have its specific control range to areal density, sodium ion battery negative pole material layer single face areal density is 25 ~ 75g/m 2 。
As shown in fig. 2, as another embodiment of the present invention, a conductive adhesive layer 400 is further coated between the negative electrode material layer 500 of the sodium ion battery and the current collector 100.
The utility model discloses to the different characteristics of sodium ion battery material system and lithium ion battery, its technical starting point is as follows: the gram capacity of the polyanionic active material of the positive electrode of the sodium ion battery is far lower than that of lithium cobaltate and a ternary material in a lithium ion battery, even lower than 2/3 of the gram capacity of lithium iron phosphate, while the negative electrode material for the sodium ion battery is hard carbon, and the gram capacity of the commercialized hard carbon is about 340 mAh.g -1 The medium and long term can exceed 400mAh g -1 Is far larger than the gram capacity (340-365 mAh.g) of the negative electrode graphite for the lithium ion battery -1 ) Resulting in a sodium ion battery having a much higher areal density ratio of positive and negative electrodes than a lithium ion battery, which will often result in a sodium ion battery having a very low areal density of the negative electrode (e.g., less than 40 g/m) 2 ) Bringing difficulty to actual production work.
The utility model discloses in, the coating equipment of negative pole piece is transfer formula coating machine and extrusion formula coating machine, and the former needs thick liquids to pass through the edge of a knife smoothly, and the latter needs thick liquids to pass through the slit smoothly, through the reasonable particle distribution of control in the thick liquids, and the component in the thick liquids is stable, do not reunite.
In order to effectively ensure the coating uniformity of the negative plate, dispersed CNT slurry is adopted as a conductive agent in the sodium-ion negative material layer to replace easily agglomerated carbon black powder conductive agent, so that the probability of abnormal occurrence can be reduced. Before blending, the hard carbon powder is mixed with alcohols (such as ethanol) to wet the surfaces of the particles, reduce the surface tension of graphite and facilitate the reduction of agglomeration among graphite particles, especially among small particles. The pretreatment of the hard carbon with a surfactant (e.g., ethanol) reduces the surface energy of the hard carbon particles and reduces the tendency of agglomeration between particles, thereby reducing the probability of scratches and graininess.
Another aspect of the present invention is to protect the sodium ion battery, which is formed by winding or laminating the above-mentioned low surface density negative electrode plate of the sodium ion battery.
In order to verify the technical effect of the utility model, the following formula is adopted: hard carbon Type 2/conductive agent SP/thickener CMC/binder SBR in a ratio of 95%/1%/1.5%/2.5%. HardThe tap density of carbon is 0.68g/cm 3 . Stirring by a process known by engineers in the art, sieving with a 100-mesh sieve, and respectively processing into the final product with a single-side surface density of 35g/m 2 And 55g/m 2 And (4) coating.
The coating appearance was good, and the correspondence between the thickness and the areal density was as follows:
by analyzing and observing the negative pole piece, the coating effect and the thickness of the pole piece are in accordance with expectations.
In the description of the present invention, it is to be understood that the terms such as "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like, indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore, should not be construed as limiting the present invention.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically limited otherwise.
In the present invention, unless otherwise explicitly specified or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly, e.g., as being fixedly connected, detachably connected, or integrated; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meaning of the above terms in the present invention can be understood according to specific situations by those skilled in the art.
The above embodiments are only specific embodiments of the present invention, and the description thereof is specific and detailed, but not construed as limiting the scope of the present invention. It should be noted that, for a person skilled in the art, many variations and modifications are possible without departing from the inventive concept, and such obvious alternatives fall within the scope of the invention.
Claims (10)
1. The utility model provides a sodium ion battery negative pole piece of low areal density, includes the mass flow body, the mass flow body includes negative and positive face, its characterized in that: the negative surface and the positive surface of the current collector are coated with a sodium ion battery negative electrode material layer, and the thickness H of the coated negative electrode sheet satisfies the following relation: h = D/(P + K) 10000 + 2+ c;
wherein D is the single-sided areal density and the unit is g/m 2 (ii) a P is the tap density of the powder of the negative electrode material and has a unit of g/cm 3 (ii) a K is an adjusting coefficient, the value of K is 0.15-0.25, and the unit is g/cm 3 (ii) a And C is the thickness of the current collector and has a unit of μm.
2. The low areal density sodium-ion battery negative plate of claim 1, wherein: the thickness h of the wet film in the coating process of the negative plate meets the following relational expression: h = (H-C)/2/S; wherein h is the thickness of the single-sided wet film, and S is the solid content of the slurry.
3. The negative plate of the low-areal density sodium-ion battery of claim 2, wherein: the negative electrode material layer of the sodium ion battery is a hard carbon material layer.
4. The low areal density sodium-ion battery negative plate of claim 3, wherein: the minimum grain diameter D0 of the hard carbon material is more than or equal to 0.5um.
5. The negative plate of the low-areal density sodium-ion battery of claim 4, wherein: the current collector is an aluminum foil, and the aluminum foil is a single-side hair aluminum foil or a double-side hair aluminum foil.
6. The low areal density sodium-ion battery negative plate of claim 5, wherein: the thickness of the current collector is 2-20 μm; the thickness of one side of the dried non-rolled negative electrode material layer of the sodium ion battery is 40-90 mu m.
7. The low areal density sodium-ion battery negative plate of claim 6, wherein: the thickness of the negative electrode material layer of the sodium ion battery coated on the negative surface and the positive surface of the current collector is the same or different.
8. The negative plate of the low-areal density sodium-ion battery of claim 7, wherein: the single-side surface density of the negative electrode material layer of the sodium ion battery is 25-75 g/m 2 。
9. The low areal density sodium-ion battery negative plate of claim 8, wherein: and a conductive adhesive layer is coated between the negative electrode material layer of the sodium-ion battery and the current collector.
10. A sodium ion battery characterized by being formed by winding or laminating the low areal density sodium ion battery negative electrode sheet according to any one of claims 1 to 9.
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| CN202222407623.3U CN218447965U (en) | 2022-09-09 | 2022-09-09 | Sodium ion battery negative plate with low surface density and sodium ion battery |
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| CN202222407623.3U CN218447965U (en) | 2022-09-09 | 2022-09-09 | Sodium ion battery negative plate with low surface density and sodium ion battery |
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