High-energy-density lithium ion battery
By adopting a double-open shell design with foamed silicone in lithium-ion batteries, the expansion problem of silicon material during circulation is solved, the energy density of the battery is improved and the adverse reactions between the shell and the electrolyte are avoided.
Patent Information
- Application Number
- CN202411805673.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-09
- Publication Date
- 2025-03-04
AI Technical Summary
During the circulation process, existing lithium-ion batteries have insufficient energy density and adverse reactions caused by contact with the electrolyte due to the volume expansion of silicon material, poor conductivity and unstable SEI film.
A double-opened shell with foamed silicone is used to put the battery cell in it, and the foamed silicone is filled in the inner wall of the shell to absorb the stress of the expansion of the battery cell, and to avoid direct contact between the shell and the electrolyte through the design of the shell.
It effectively suppresses the expansion of the battery cell, increases the energy density of the lithium-ion battery, reduces the expansion of the battery cell thickness, and avoids adverse reactions between the shell and the electrolyte.
Smart Images
Figure CN119560620A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of lithium ion batteries, and in particular to a high energy density lithium ion battery. Background Art
[0002] At present, lithium-ion batteries have successfully dominated the portable electronic product market. Driven by emerging technologies, consumer electronic products tend to be thinner and more durable, which puts higher requirements on the energy density of lithium-ion batteries. The theoretical specific capacity of silicon-based materials (4200mAh g -1 ) is about the graphite negative electrode (372mAh g -1 ), and silicon is abundant in the earth's crust and environmentally friendly, which has obvious advantages. However, silicon will produce huge volume expansion, poor conductivity and unstable SEI film during the cycle. The existing expansion suppression technology is to put the assembled bare battery cell into a steel shell, and then seal the steel shell through welding, sealing and other processes to ensure that the inside of the battery is not affected by the outside world. However, the steel shell material may react adversely with the internal electrolyte, affecting the performance and life of the battery.
[0003] Therefore, it is of great significance to provide a high energy density lithium ion battery that effectively avoids direct contact and reaction between the shell and the electrolyte and effectively reduces the expansion of the battery cell. Summary of the invention
[0004] The purpose of the present invention is to provide a high energy density lithium ion battery in order to overcome the deficiencies of the prior art.
[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:
[0006] The present invention provides a high energy density lithium ion battery. The main body of the high energy density lithium ion battery has an expansion suppression device. The battery expansion suppression device comprises a shell, foamed silica gel, and a battery core.
[0007] The foamed silica gel is filled on the inner wall of the shell, and the filling thickness of the foamed silica gel is 0.3-5 mm.
[0008] Preferably, the negative electrode of the battery cell is a silicon-carbon composite material, and the mass fraction of silicon-carbon particles in the silicon-carbon composite material is 15-50%.
[0009] Preferably, the shell is a hollow shell, which is sleeved on the main body of the battery cell, and the ear side and bottom of the battery cell are exposed.
[0010] Preferably, the leakage length on the lug side is 10 to 30 mm, and the leakage length on the bottom is 1 to 10 mm.
[0011] Preferably, the hollow shell is an internal hollow shell with openings at both ends.
[0012] Preferably, the foamed silicone is closely filled on the four inner walls of the shell, and the Shore A hardness of the foamed silicone is 5 to 80 degrees.
[0013] Preferably, the filling area of the foamed silica gel is 50-100% of the inner wall area of the shell.
[0014] Preferably, the battery cell is fixed by the friction between the battery cell and the foamed silica gel.
[0015] The beneficial effects of the present invention include the following:
[0016] 1) The battery expansion suppression device of the present invention comprises a shell, foamed silica gel and a battery cell, the negative electrode of the battery cell is a silicon-carbon composite material, and the battery expansion suppression device can suppress the volume expansion of the silicon-carbon material during the cycle; the battery cell of the present invention has high capacity and thin thickness, and the high energy density battery cell is placed in a double-open shell with foamed silica gel, wherein the shell is not in contact with the electrolyte, and the foamed silica gel can absorb the expansion stress of the battery cell, so that the internal stress of the battery cell expansion is released through the foamed silica gel, thereby suppressing the expansion of the battery cell and further improving the energy density of the battery. The design of the high specific energy negative electrode plus the expansion suppression device increases the energy density of the battery of the present invention by more than 8.72%, and reduces the thickness expansion of the battery cell by more than 3.97%.
[0017] 2) The present invention directly inserts the battery cell into a double-opening shell with foamed silica gel. The foamed silica gel filled in the shell can absorb the stress of the battery cell expansion. The double-opening hollow shell can effectively inhibit the expansion to obtain a high energy density battery. While inhibiting the expansion of the battery cell, the present invention can also effectively avoid the expansion inhibition shell from directly contacting and reacting with the electrolyte. In addition, the high energy density battery of the present invention has a simple structure, simple operation and low cost of use. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Figure 1 is a schematic top view of a high energy density lithium ion battery of the present invention;
[0019] Figure 2 A three-dimensional diagram of a hollow structure housing with double openings and a battery cell of the present invention;
[0020] Among them, 1 is the shell, 2 is the foamed silicone, and 3 is the battery core. DETAILED DESCRIPTION
[0021] The present invention provides a high energy density lithium ion battery. The main body of the high energy density lithium ion battery has an expansion suppression device. The battery expansion suppression device comprises a shell, foamed silica gel, and a battery core.
[0022] The foamed silica gel is filled on the inner wall of the shell, and the filling thickness of the foamed silica gel is 0.3-5 mm.
[0023] In the present invention, the filling thickness of the foamed silica gel is preferably 0.8 to 4 mm, more preferably 1.5 to 3.5 mm, and even more preferably 2 to 3 mm.
[0024] In the present invention, the negative electrode of the battery cell is preferably a silicon-carbon composite material, and the mass fraction of silicon-carbon particles in the silicon-carbon composite material is preferably 15-50%, more preferably 25-45%, and even more preferably 35-40%.
[0025] In the present invention, the silicon-carbon composite material is a silicon-carbon composite material with high specific capacity; the battery cell of the present invention is light and thin and has high capacity.
[0026] Silicon-carbon composite materials are composed of silicon-carbon materials and graphite. The silicon-carbon material is prepared by chemical vapor deposition and has the characteristics of long cycle, low expansion, high initial efficiency, etc. The graphite is a high-compaction, low-expansion, fast-filling artificial graphite.
[0027] In the present invention, the shell is preferably a hollow shell, and the shell is preferably sleeved on the main body of the battery cell, with the tab side and the bottom of the battery cell leaking out.
[0028] In the present invention, the leakage length on the tab side is preferably 10 to 30 mm, more preferably 15 to 25 mm, and more preferably 20 mm, and the leakage length on the bottom is preferably 1 to 10 mm, more preferably 3 to 8 mm, and more preferably 5 to 6 mm.
[0029] In the present invention, the hollow shell is preferably an internal hollow shell with openings at both ends; the battery cell is directly inserted from the shell opening, and the battery cell body is located inside the shell.
[0030] In the present invention, the foamed silica gel is preferably filled in close contact with the four inner walls of the shell, and the Shore A hardness of the foamed silica gel is preferably 5 to 80 degrees, more preferably 10 to 70 degrees, and even more preferably 30 to 50 degrees.
[0031] In the present invention, the filling area of the foamed silica gel is preferably 50 to 100% of the inner wall area of the shell, more preferably 60 to 90% of the inner wall area of the shell, and even more preferably 70 to 80% of the inner wall area of the shell.
[0032] In the present invention, the surface of the foamed silica gel is smooth and can fit tightly with the battery after filling.
[0033] In the present invention, the foamed silica gel is preferably organic silicone foamed silica gel or polyurethane foamed silica gel.
[0034] In the present invention, the battery core is fixed by the friction between the battery core and the foamed silica gel.
[0035] The technical solutions provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the protection scope of the present invention.
[0036] In the embodiment, the silicon-carbon composite material is composed of a silicon-carbon material and graphite, wherein the silicon-carbon material is prepared by chemical vapor deposition; and the graphite is a high-compaction, low-expansion, fast-filling artificial graphite.
[0037] Example 1
[0038] The main body of the high energy density lithium-ion battery has an expansion suppression device, which includes a shell, foamed silica gel, and a battery cell; the foamed silica gel is foamed silica gel PU65;
[0039] The foamed silicone is closely attached to the inner walls of the shell on all four sides. The Shore A hardness of the foamed silicone is 65 degrees, and the filling thickness of the foamed silicone is 3mm. The filling area of the foamed silicone is 80% of the inner wall area of the shell.
[0040] The shell is an internal hollow shell with openings at both ends. The shell filled with foamed silicone is sleeved on the main body of the battery core. The battery core is fixed by the friction between the foamed silicone filled with the inner wall of the shell. The surface of the foamed silicone is smooth and can fit tightly with the inner wall of the shell after filling.
[0041] The leakage is on the ear side and bottom of the battery cell, with the ear side leakage length of 20 mm and the bottom leakage length of 5 mm; the negative electrode of the battery cell is a silicon-carbon composite material with high specific capacity, in which the mass fraction of silicon-carbon particles is 30%.
[0042] Compared with a conventional graphite system without an expansion suppression device, the energy density of the high energy density lithium ion battery of this embodiment is increased by 8.8%, and the thickness expansion of the battery cell is reduced by 4.01%.
[0043] Example 2
[0044] The main body of the high energy density lithium-ion battery has an expansion suppression device, which includes a shell, foamed silica gel, and a battery cell; the foamed silica gel is foamed silica gel SY-1570E;
[0045] The foamed silicone is closely attached to the inner walls of the shell on all four sides. The Shore A hardness of the foamed silicone is 20 degrees, and the filling thickness of the foamed silicone is 1.5 mm. The filling area of the foamed silicone is 60% of the inner wall area of the shell.
[0046] The shell is an internal hollow shell with openings at both ends. The shell filled with foamed silicone is sleeved on the main body of the battery core. The battery core is fixed by the friction between the foamed silicone filled with the inner wall of the shell. The surface of the foamed silicone is smooth and can fit tightly with the inner wall of the shell after filling.
[0047] The battery cell leaks out from the ear side and bottom, with the ear side leakage length being 15 mm and the bottom leakage length being 3 mm. The negative electrode of the battery cell is a silicon-carbon composite material with a high specific capacity, in which the mass fraction of silicon-carbon particles is 25%.
[0048] Compared with a conventional graphite system without an expansion suppression device, the energy density of the high energy density lithium ion battery of this embodiment is increased by 8.72%, and the thickness expansion of the battery cell is reduced by 3.99%.
[0049] Example 3
[0050] The main body of the high energy density lithium-ion battery has an expansion suppression device, which includes a shell, foamed silica gel, and a battery cell; the foamed silica gel is foamed silica gel SC903;
[0051] The foamed silicone is closely attached to the inner walls of the shell on all four sides. The Shore A hardness of the foamed silicone is 70 degrees, and the filling thickness of the foamed silicone is 4mm. The filling area of the foamed silicone is 90% of the inner wall area of the shell.
[0052] The shell is an internal hollow shell with openings at both ends. The shell filled with foamed silicone is sleeved on the main body of the battery core. The battery core is fixed by the friction between the foamed silicone filled with the inner wall of the shell. The surface of the foamed silicone is smooth and can fit tightly with the inner wall of the shell after filling.
[0053] The battery cell leaks out from the ear side and bottom, with the ear side leaking out for 25 mm and the bottom leaking out for 8 mm. The negative electrode of the battery cell is a silicon-carbon composite material with a high specific capacity, in which the mass fraction of silicon-carbon particles is 35%.
[0054] Compared with a conventional graphite system without an expansion suppression device, the energy density of the high energy density lithium ion battery of this embodiment is increased by 8.75%, and the thickness expansion of the battery cell is reduced by 3.97%.
[0055] The present invention provides a battery with a double-opening shell with foamed silica gel on the outside of the battery core, which effectively avoids the problem of direct contact and reaction between the shell and the electrolyte. The expansion of the battery core has an extrusion effect on the foamed silica gel, and the internal stress of the battery core expansion can be released to a certain extent through the foamed silica gel, effectively reducing the expansion of the battery core, thereby improving the energy density of the lithium-ion battery.
[0056] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.
Claims
1. A high energy density lithium ion battery, characterized in that: The main body of the high energy density lithium-ion battery has an expansion suppression device, and the battery expansion suppression device includes a shell, foamed silica gel, and a battery cell; The foamed silica gel is filled on the inner wall of the shell, and the filling thickness of the foamed silica gel is 0.3 to 5 mm.
2. The high energy density lithium ion battery according to claim 1, characterized in that: The negative electrode of the battery cell is a silicon-carbon composite material, in which the mass fraction of silicon-carbon particles is 15-50%.
3. The high energy density lithium ion battery according to claim 1 or 2, characterized in that: The shell is a hollow shell, which is sleeved on the main body of the battery cell, and the ear side and bottom of the battery cell are exposed.
4. The high energy density lithium ion battery according to claim 3, characterized in that: The leakage length on the ear side is 10 to 30 mm, and the leakage length on the bottom is 1 to 10 mm.
5. The high energy density lithium ion battery according to claim 3, characterized in that: The hollow shell is an internal hollow shell with openings at both ends.
6. The high energy density lithium ion battery according to claim 4 or 5, characterized in that: The foamed silicone is closely filled with the four inner walls of the shell, and the Shore A hardness of the foamed silicone is 5 to 80 degrees.
7. The high energy density lithium ion battery according to claim 6, characterized in that: The filling area of the foamed silica gel is 50 to 100% of the inner wall area of the shell.
8. The high energy density lithium ion battery according to claim 7, characterized in that: The battery cell is fixed by the friction between the battery cell and the foamed silicone.