A lithium battery with high energy density

Abstract

The present invention relates to a lithium battery with a high energy density, belonging to the technical field of lithium batteries. Aiming at the problem of inconvenient connection of the tab in the existing products, the following technical solutions are proposed, including a housing. A battery core package is arranged inside the housing, and an electrode end cover is arranged above the battery core package. A tab is connected between the battery core package and the electrode end cover. The electrode end cover includes a cover plate, and a plurality of electrode posts are arranged on the cover plate. A clamping assembly is installed at the bottom of the electrode post. The tab includes a tab body welded to the battery core package, and a convex block is integrally arranged on the tab body. By setting the cooperation between the clamping assembly and the tab, the connection of the tab can be pre-limited when the tab is welded to the electrode end cover, replacing the support-type welding method used in the prior art, thereby facilitating the welding and fixing, improving the work efficiency, and further improving the energy density of the battery by improving the electrode active material in this device.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium batteries, and particularly to a lithium battery with high energy density. Background Art

[0002] Lithium batteries have the advantages of a wide operating temperature range, stable discharge voltage, low self-discharge rate, long service life, etc., and have been widely used in various fields. For example, the power batteries used in new energy electric vehicles. Currently, the driving range of new energy electric vehicles still cannot reach that of fuel vehicles, especially unable to meet the demand for long-distance commuting. The key to improving the driving range of electric vehicles lies in improving the energy density level of power batteries.

[0003] Existing lithium batteries, such as a Chinese patent with an authorized announcement number of CN202549998U, disclose a lithium-ion battery. The lithium-ion battery is cylindrical, including a cylindrical outer shell. Positive and negative end caps are provided at both ends of the cylinder. The lithium-ion battery further includes a positive electrode terminal and a negative electrode terminal. A positive current collector plate is provided in the space between the positive end cap and the core shaft, and the positive current collector plate is connected to the positive end cap through a positive electrode tab; a negative current collector plate is provided in the space between the negative end cap and the core shaft, and the negative current collector plate is connected to the negative end cap through a negative electrode tab; a rolling groove is provided at the positions of the positive electrode tab and the negative electrode tab on the cylindrical outer shell, and the rolling groove surrounds the cylinder for one week. This battery uses a cylindrical metal outer shell, and rolling grooves are provided at both ends of the shell. The inner concave part of the rolling groove is used to effectively fix the battery core winding body inside the battery, thereby increasing the internal space of the battery, improving the overall performance of the battery, and extending the service life of the battery to 5 to 15 years.

[0004] Although the technical solution in the above comparative document extends the service life of the battery, it still has the following defects:

[0005] When the electrode tab of an existing lithium battery is connected to the electrode end cap, it is necessary to support and align the two to ensure the accuracy of the welding position of the electrode tab. However, such an assembly method has low efficiency. Although the lithium iron phosphate material used for the electrode end of the existing lithium battery has advantages such as good safety performance and long service life, with the development of new energy electric vehicles, the requirements for lithium battery power sources are also constantly increasing, and thus a lithium battery with higher energy density is needed.

[0006] Therefore, how to process lithium batteries is a technical problem that those skilled in the art need to solve currently. Summary of the Invention

[0007] The object of the present invention is to propose a lithium battery with high energy density that is convenient for positioning and welding of electrode tabs in view of the problems in the background art.

[0008] Technical solution of the present invention: A lithium battery with high energy density includes a housing. Inside the housing, there is a battery core package. Above the battery core package, there is an electrode end cap. Between the battery core package and the electrode end cap, there is a tab connected. The electrode end cap includes a cover plate. On the cover plate, there are multiple electrode posts. At the bottom of the electrode posts, there is a clamping component installed. The tab includes a tab body welded to the battery core package. On the tab body, there is a convex block integrally provided. On the convex block, there is a positioning hole opened.

[0009] Preferably, through grooves are symmetrically opened on the front and back of the cover plate. The electrode posts include a positive electrode post and a negative electrode post. The positive electrode post and the negative electrode post are respectively arranged in the symmetric through grooves.

[0010] Preferably, the positive electrode post includes a positive electrode guide plate and a positive electrode head. The positive electrode head is integrally provided at the top of the positive electrode guide plate, and the positive electrode guide plate is located in the front through groove.

[0011] Preferably, the negative electrode post includes a negative electrode guide plate and a negative electrode head. The negative electrode head is integrally provided at the top of the negative electrode guide plate, and the negative electrode guide plate is located in the rear through groove.

[0012] Preferably, the clamping component includes an L-shaped plate. On both sides of the top of the L-shaped plate, there are buckling edge plates provided. And at the bottom of the L-shaped plate, there is a connecting strip welded. On the connecting strip, there is a limiting post installed.

[0013] Preferably, on the middle shell wall of the top of the L-shaped plate, there is a groove opened. On the bottom shell wall of the groove, there is a limiting hole opened. The limiting post is movably connected with the limiting hole.

[0014] Preferably, the top of the tab is clamped on the clamping component.

[0015] Preparation method of a high energy density battery, including a positive electrode paste and a negative electrode paste. The positive electrode paste includes lithium iron phosphate, lithium manganese iron phosphate, PVDF, SP and KS-6. And lithium iron phosphate and lithium manganese iron phosphate are mixed in a ratio of 1:1. The negative electrode paste includes graphite, LA132 and SP.

[0016] Preferably, in the positive electrode paste, both lithium iron phosphate and lithium manganese iron phosphate account for 40%-60% of the total product. PVDF, SP and KS-6 each account for 1%-5% of the total product.

[0017] Preferably, in the negative electrode paste, graphite accounts for 90%-98% of the total product. LA132 and SP each account for 1%-5% of the total product.

[0018] Compared with the prior art, the present invention has the following beneficial technical effects:

[0019] By setting the cooperation between the clamping component and the tab, the connection of the tab can be pre-limited when welding the tab to the electrode end cover, replacing the supporting welding method used in the prior art, thereby facilitating the welding and fixing, improving the work efficiency. Moreover, in this device, by improving the electrode active material, the energy density of the battery is further increased. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Schematic diagram of the three-dimensional structure of an embodiment of the present invention is given Figure One ;

[0021] Figure 2 Schematic diagram of the three-dimensional structure of an embodiment of the present invention is given Figure Two ;

[0022] Figure 3 is Figure 2 the three-dimensional structure schematic diagram of the clamping component;

[0023] Figure 4 is Figure 3 the side elevation structure schematic diagram.

[0024] Reference numerals: 1, outer shell; 2, battery core package; 3, electrode end cover; 31, cover plate; 32, electrode post; 321, positive electrode post; 3211, positive electrode guide plate; 3212, positive electrode head; 322, negative electrode post; 3221, negative electrode guide plate; 3222, negative electrode head; 33, clamping component; 331, L-shaped plate; 332, buckle plate; 333, connecting bar; 334, limiting column; 335, groove; 336, limiting hole; 4, tab; 41, tab body; 42, convex block; 43, positioning hole. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0025] The technical solutions of the present invention will be further described below with reference to the accompanying drawings and specific embodiments. Embodiment

[0026] As Figure 1 shown, a high-energy density lithium battery proposed by the present invention includes an outer shell 1. A battery core package 2 is arranged inside the outer shell 1. An electrode end cover 3 is arranged above the battery core package 2. A tab 4 is connected between the battery core package 2 and the electrode end cover 3. The electrode end cover 3 includes a cover plate 31. A plurality of electrode posts 32 are arranged on the cover plate 31. A clamping component 33 is installed at the bottom of the electrode post 32. The tab 4 includes a tab body 41 welded to the battery core package 2. A convex block 42 is integrally arranged on the tab body 41. A positioning hole 43 is opened on the convex block 42.

[0027] In this embodiment, the conductive connecting plate between the battery core pack 2 and the electrode end cap 3 is eliminated in the structural design of the battery, and the pole ear 4 of the battery core pack 2 is directly welded to the electrode end cap 3, which can save the internal space of the battery and effectively improve the energy density of the battery.

[0028] The working principle of a high energy density lithium battery based on the first embodiment is: when the battery is assembled, the battery core pack 2 is first placed in the shell 1, and then one end of the pole ear 4 is welded to the top of the battery core pack 2. After the pole ear 4 is fixed, the electrode end cap 3 is assembled. When assembling the electrode end cap 3, the end of the pole ear 4 away from the battery core pack 2 is first clamped on the clamping assembly 33 of the electrode end cap 3, and the pole ear 4 and the electrode end cap 3 are welded and fixed. After the pole ear 4 is fixed, the electrode end cap 3 and the top of the shell 1 are pressed and assembled to realize the assembly of the battery. Example

[0029] like Figures 2 - 4 As shown, a high energy density lithium battery proposed by the present invention, compared with the first embodiment, this embodiment further includes: a through groove is symmetrically opened on the cover plate 31, the electrode column 32 includes a positive electrode column 321 and a negative electrode column 322, the positive electrode column 321 and the negative electrode column 322 are respectively arranged in the symmetrical through groove, the positive electrode column 321 includes a positive electrode guide plate 3211 and a positive electrode column head 3212, the positive electrode column head 3212 is integrally arranged on the top of the positive electrode guide plate 3211, and the positive electrode guide plate 3211 is located in the front through groove, the negative electrode column 322 includes a negative electrode guide plate 3221 and a negative electrode column head 3222, the negative electrode column 322 includes a negative electrode guide plate 3221 and a negative electrode column head 3222, The pole head 3222 is integrally arranged on the top of the negative guide plate 3221, and the negative guide plate 3221 is located in the rear through groove. The clamping assembly 33 includes an L-shaped plate 331. Buckle plates 332 are arranged on both sides of the top of the L-shaped plate 331, and a connecting strip 333 is welded to the bottom of the L-shaped plate 331. A limiting column 334 is installed on the connecting strip 333. A groove 335 is provided on the middle shell wall of the top of the L-shaped plate 331, and a limiting hole 336 is provided on the bottom shell wall of the groove 335. The limiting column 334 is movably connected to the limiting hole 336, and the top of the pole ear 4 is clamped on the clamping assembly 33.

[0030] In this embodiment, both the clamping assembly 33 and the tab 4 are made of soft and bendable materials, so that they can be easily adjusted by being moved.

[0031] In this embodiment, when assembling the tab 4 and the electrode end cap 3, the top of the tab body 41 in the tab 4 is snapped onto the snap-fit assembly 33, and the bump 42 on the tab body 41 is snapped into the groove 335, while the positioning hole 43 corresponds to the limiting hole 336. After the tab body 41 is placed in position, the connecting bar 333 is pressed, so that the limiting post 334 on the connecting bar 333 extends into the limiting hole 336 and is inserted into the interior of the positioning hole 43, thereby achieving preliminary limitation of the tab body 41. After the preliminary limitation of the tab body 41 is completed, the bottom of the L-shaped plate 331 is pressed, so that the L-shaped plate 331 folds upward. As the L-shaped plate 331 folds, the buckling edge plate 332 on the L-shaped plate 331 is pressed upward along with the L-shaped plate 331, and then the buckling edge plates 332 approach and fold towards each other. During the process of the buckling edge plates 332 approaching and folding towards each other, the tab body 41 placed on the L-shaped plate 331 is tightly fixed, further achieving limitation of the tab body 41. After the tab body 41 is limited and fixed, the tab 4 is welded to the electrode post 32. Embodiment

[0032] As Figure 1 shown, the preparation method of the high energy density battery proposed by the present invention, compared with Embodiment 1 or Embodiment 2, this embodiment further includes: including a positive electrode paste and a negative electrode paste. The positive electrode paste includes lithium iron phosphate, lithium manganese iron phosphate, PVDF, SP, and KS-6, and lithium iron phosphate and lithium manganese iron phosphate are mixed in a ratio of 1:1. The negative electrode paste includes graphite, LA132, and SP. In the positive electrode paste, both lithium iron phosphate and lithium manganese iron phosphate account for 40%-60% of the total product, PVDF, SP, and KS-6 each account for 1%-5% of the total product. In the negative electrode paste, graphite accounts for 90%-98% of the total product, and LA132 and SP each account for 1%-5% of the total product.

[0033] In this embodiment, the lithium iron phosphate battery is a mainstream lithium-ion power battery. The active material at the positive electrode end uses lithium iron phosphate material, and the actual specific capacity of this material is greater than 140 mAh / g, the voltage range is between 2V - 4V, and the energy density has exceeded 180 Wh / Kg.

[0034] In this embodiment, the performance of the lithium manganese iron phosphate material is similar to that of the lithium iron phosphate material, and it has a higher voltage range. Under the same conditions, the energy density is 10%-20% higher than that of lithium iron phosphate.

[0035] In this embodiment, an ultrasonic device is added in the coating process at the manufacturing end of the positive electrode paste and the negative electrode paste. Before the coated electrode sheet enters the electrode sheet oven after coating, it first passes through the ultrasonic device. This device emits ultrasonic waves with a certain intensity and frequency to vibrate the electrode sheet, making the coating particle distribution on the electrode sheet more uniform and compact, which can improve the compression ratio of the electrode sheet and thus increase the energy density of the battery, and can also promote the absorption of the electrolyte by the electrode sheet, saving solvent materials.

[0036] The above specific embodiments are only several preferred embodiments of the present invention. Based on the technical solution of the present invention and the relevant inspirations of the above embodiments, those skilled in the art can make various alternative improvements and combinations to the above specific embodiments.

Claims

1. A lithium battery with high energy density, comprising a housing, a battery core package is arranged inside the housing, an electrode end cap is arranged above the battery core package, and a tab is connected between the battery core package and the electrode end cap, and it is characterized in that: The electrode end cover includes a cover plate, on which a plurality of electrode posts are provided. A clamping component is installed at the bottom of the electrode posts. Through grooves are symmetrically opened on the front and back of the cover plate. The electrode posts include a positive electrode post and a negative electrode post, and the positive electrode post and the negative electrode post are respectively arranged in the symmetrically distributed through grooves; the positive electrode post includes a positive electrode guide plate and a positive electrode head, the positive electrode head is integrally arranged at the top of the positive electrode guide plate, and the positive electrode guide plate is located in the front through groove; the negative electrode post includes a negative electrode guide plate and a negative electrode head, the negative electrode head is integrally arranged at the top of the negative electrode guide plate, and the negative electrode guide plate is located in the rear through groove; The clamping component includes an L-shaped plate. On both sides of the top of the L-shaped plate, buckle side plates are provided, and a connecting strip is welded to the bottom of the L-shaped plate. A limiting post is installed on the connecting strip; a groove is opened on the middle shell wall of the top of the L-shaped plate, and a limiting hole is opened on the bottom shell wall of the groove. The limiting post is movably connected with the limiting hole; the tab includes a tab body welded on the battery core package. A convex block is integrally arranged on the tab body, and a positioning hole is opened on the convex block. The top of the tab is clamped on the clamping component; When the battery is assembled, first place the battery core package in the outer shell, and then weld one end of the tab to the top of the battery core package. After the tab is fixed, assemble the electrode end cover; When assembling the electrode end cover, first clamp the end of the tab away from the battery core package on the clamping component of the electrode end cover, and then weld and fix between the tab and the electrode end cover. After the tab is fixed, press and assemble the electrode end cover and the top end of the outer shell to complete the assembly of the battery; Among them, when assembling the tab and the electrode end cover, the top of the tab body in the tab is clamped on the clamping component, and the convex block on the tab body is clamped into the groove, and the positioning hole corresponds to the limiting hole. After the tab body is placed correspondingly, press the connecting strip so that the limiting post on the connecting strip extends into the limiting hole and inserts into the inside of the positioning groove, thereby realizing the preliminary limiting of the tab body. After the preliminary limiting of the tab body is completed, press the bottom of the L-shaped plate so that the L-shaped plate folds upward. As the L-shaped plate folds, the buckle side plates on the L-shaped plate are pressed upward as the L-shaped plate, and then the buckle side plates approach and fold each other. During the process of the buckle side plates approaching and folding each other, the tab body placed on the L-shaped plate is tightly fixed, further realizing the limiting of the tab body. After the tab body is limited and fixed, weld the tab to the electrode post.

2. The high-energy density lithium battery according to claim 1, comprising a positive electrode paste and a negative electrode paste, characterized in that: The positive electrode paste includes lithium iron phosphate, lithium manganese iron phosphate, PVDF, SP and KS-6, and lithium iron phosphate and lithium manganese iron phosphate are mixed in a ratio of 1:

1. The negative electrode paste includes graphite, LA132 and SP.

3. The high-energy density lithium battery according to claim 2, wherein In the positive electrode paste, both lithium iron phosphate and lithium manganese iron phosphate account for 40%-60% of the total product, and PVDF, SP and KS-6 each account for 1%-5% of the total product.

4. The high-energy density lithium battery according to claim 3, wherein: In the negative electrode paste, graphite accounts for 90%-98% of the total product, and LA132 and SP each account for 1%-5% of the total product.

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