Tab assembly, lithium ion battery and electric equipment
By using aluminum and copper nickel-plated ears and adjusting their structural parameters, the problem of difficulty in taking into account explosion-proof performance and flexibility of lithium batteries in 3mΩ short circuit test is solved, and the effect of controlling the temperature within 130℃ is achieved to avoid liquid leakage .
Patent Information
- Application Number
- CN202411452869.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-17
- Publication Date
- 2025-02-18
AI Technical Summary
Existing lithium batteries are difficult to take into account both explosion-proof performance and flexible performance in shape and size, especially in 3mΩ short-circuit test, which limits their wide application.
The first electrode ear of aluminum and the second electrode ear of copper nickel plated are used to adjust the ratio of its cross-sectional area and thickness or width to reduce the impedance of the first electrode ear, and the copper nickel plated electrode connected to the negative electrode sheet. Ear combination reduces Joule heat during short-circuit discharge.
During the 3mΩ short circuit test, the temperatures of the first and second electrodes do not exceed 130℃, which avoids the battery cell ear from being fused or the PP glue melts at the ears, resulting in fluid leakage, achieving flexibility in shape and size Take into account both sexual and explosion-proof needs.
Smart Images
Figure CN119481602A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of lithium batteries, and in particular to a tab assembly, a lithium ion battery and electrical equipment. Background Art
[0002] With the rapid development of electronic equipment and new energy vehicle industries, the safety and performance requirements for batteries are increasing. As a key experiment, the 3mΩ short-circuit test is used to evaluate the safety of batteries under extreme short-circuit conditions and is an important criterion for measuring battery design and manufacturing quality. At present, hard-shell lithium batteries can effectively improve the safety of batteries and pass the 3mΩ short-circuit test by adopting explosion-proof devices such as pressure relief valves and explosion-proof valves.
[0003] However, the structural rigidity of hard-shell lithium batteries limits their flexibility in shape and size, making it difficult to meet the growing demand for customized design. In contrast, soft-pack lithium batteries have significant advantages in portable devices and special application scenarios due to their lightness, thinness, and strong plasticity. However, due to their structural characteristics, it is difficult to set up effective explosion-proof devices for soft-pack lithium batteries, resulting in poor performance in the 3mΩ short-circuit test, which has become a key technical bottleneck restricting their widespread application. Summary of the invention
[0004] The embodiments of the present invention provide a tab assembly, a lithium-ion battery and an electrical device to solve the problem that the existing lithium battery is difficult to achieve both explosion-proof performance and flexible performance in shape and size.
[0005] Specifically, the present invention provides a pole ear assembly, comprising a first pole ear and a second pole ear, wherein the first pole ear is an aluminum pole ear, and the second pole ear is a copper-nickel-plated pole ear; the ratio of the cross-sectional area of the first pole ear to the cross-sectional area of the second pole ear is greater than 1.3.
[0006] Optionally, the width W1 of the first pole tab is the same as the width W2 of the second pole tab, and the thickness T1 of the first pole tab and the thickness T2 of the second pole tab satisfy: T1 ≥ 1.5T2.
[0007] Optional, T1≤3T2.
[0008] Optionally, the width W1 of the first pole ear is 3 mm to 100 mm; The thickness T1 of the first pole tab is 0.15 mm to 0.6 mm, and the thickness T2 of the second pole tab is 0.1 mm to 0.4 mm.
[0009] Optionally, the thickness T1 of the first pole tab is the same as the thickness T2 of the second pole tab, and the width W1 of the first pole tab and the width W2 of the second pole tab satisfy: W1≥1.3W2.
[0010] Optional, W1≤10W2.
[0011] Optionally, the thickness T1 of the first electrode tab is 0.1 mm to 0.3 mm; The width W1 of the first pole tab is 3.9 mm to 100 mm, and the width W2 of the second pole tab is 3 mm to 10 mm.
[0012] The present invention also provides a lithium-ion battery, comprising a battery cell body, a packaging bag and a pole ear assembly as described in any one of the above items, wherein the battery cell body is accommodated in the packaging bag; one end of the first pole ear is connected to the positive electrode of the battery cell body, and the other end extends out of the packaging bag, and one end of the second pole ear is connected to the negative electrode of the battery cell body, and the other end extends out of the packaging bag.
[0013] Optionally, the packaging bag includes a bag body and a top seal part connected to the bag body, and the battery cell body is located in the bag body; the other end of the first pole ear passes through the bag body and the top seal part and extends out of the packaging bag, and the other end of the second pole ear passes through the bag body and the top seal part and extends out of the packaging bag; pole ear glue is bonded between the first pole ear and / or the second pole ear and the top seal part.
[0014] The present invention further provides an electrical device, comprising a load and a lithium-ion battery as described in any one of the above items, wherein the lithium-ion battery is used to supply power to the load.
[0015] The beneficial effects of the present invention are: In the tab assembly, lithium-ion battery and electrical equipment provided by the present invention, since the impedance of the aluminum first tab is large and the temperature rises quickly during a 3mΩ short-circuit test, the cross-sectional area of the first tab is increased to reduce its impedance; and by matching with the copper-nickel-plated second tab connected to the negative electrode sheet, the Joule heat of the battery during the short-circuit discharge process can be reduced, so that the temperature at the first tab and the second tab does not exceed 130°C during the 3mΩ short-circuit test, thereby preventing the tab of the battery cell from being melted or the PP glue at the tab from melting to cause leakage. The battery has both flexibility in shape and size and meets explosion-proof requirements, so as to facilitate popularization and application. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative labor.
[0017] Figure 1 It is a schematic structural diagram of a lithium-ion battery in the prior art.
[0018] In the figure: 100, lithium-ion battery, 110, first pole ear, 120, second pole ear; W1, the width of the first pole tab, W2, the width of the second pole tab. DETAILED DESCRIPTION
[0019] In order to make the technical problems, technical solutions and beneficial effects solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.
[0020] During the 3mΩ short-circuit test, the battery cell will be discharged at a very large rate, and the discharge process will generate huge Joule heat and reversible chemical reaction heat of the discharge reaction. Because the heat generation rate of the battery is much greater than the heat dissipation rate, the internal temperature of the battery continues to rise; when the battery temperature exceeds 70℃, the internal side reactions of the battery will increase and release a large amount of heat generated by the side reactions, causing the battery temperature to further increase, which is easy to cause the diaphragm to melt, causing the short-circuit area to further increase, and easily causing the final thermal runaway. The standards for passing the 3mΩ short-circuit test are no fire, no explosion, no leakage, and the temperature of any part of the battery is ≤130℃.
[0021] Figure 1 is a schematic structural diagram of a lithium-ion battery in the prior art, such as Figure 1 As shown, an embodiment of the present invention provides a pole ear assembly, including a first pole ear 110 and a second pole ear 120, wherein the first pole ear 110 is an aluminum pole ear, and the second pole ear 120 is a copper-nickel-plated pole ear; the ratio of the cross-sectional area of the first pole ear 110 to the cross-sectional area of the second pole ear 120 is greater than 1.3.
[0022] The positive electrode sheet of the existing battery cell body is aluminum foil, and the negative electrode sheet is copper foil. Therefore, when used, the aluminum first pole ear 110 is connected to the positive electrode sheet of the battery cell body, and the copper-nickel-plated second pole ear 120 is connected to the negative electrode sheet. Since the impedance of the aluminum first pole ear 110 is large, it heats up quickly during the 3mΩ short-circuit test, so the cross-sectional area of the first pole ear 110 is increased to reduce its impedance; by matching it with the copper-nickel-plated second pole ear 120 connected to the negative electrode sheet, the Joule heat of the battery short-circuit discharge process can be reduced, so that the temperature at the first pole ear 110 and the second pole ear 120 does not exceed 130°C during the 3mΩ short-circuit test, avoiding the battery cell pole ear from being melted or the PP glue at the pole ear melting to cause leakage, and it has both flexibility in shape and size and explosion-proof requirements, so as to promote application.
[0023] In one embodiment of the present invention, the width W1 of the first pole ear 110 is the same as the width W2 of the second pole ear 120, and the thickness T1 of the first pole ear 110 and the thickness T2 of the second pole ear 120 satisfy: T1 ≥ 1.5T2. When this condition is met, the temperature difference between the first pole ear 110 and the second pole ear 120 can be effectively reduced to avoid affecting the temperature distribution of the battery and improve the performance of the battery. If the temperature difference between the first pole ear 110 and the second pole ear 120 is large, the aging of the battery will be accelerated, because high temperature will accelerate the decomposition of the electrolyte, the structural change of the positive electrode material, and the thickening of the solid electrolyte interface (SEI) film on the surface of the negative electrode, and these reactions will lead to a decrease in battery capacity and an increase in internal resistance. Further, T1 ≤ 3T2, so as to avoid a large difference in thickness between the first pole ear 110 and the second pole ear 120, which will increase the difficulty of packaging, and the flatness of the battery is also poor, affecting the appearance and use of the battery.
[0024] Specifically, the width W1 of the first pole tab 110 is 3 mm to 100 mm; specifically, W1 is 5 mm, 6 mm, 7 mm or 8 mm. The thickness T1 of the first pole tab 110 is 0.15 mm to 0.6 mm, and the thickness T2 of the second pole tab 120 is 0.1 mm to 0.4 mm.
[0025] In an alternative embodiment of the present invention, the thickness T1 of the first pole ear 110 is the same as the thickness T2 of the second pole ear 120, and the width W1 of the first pole ear 110 and the width W2 of the second pole ear 120 satisfy: W1≥1.3W2. When this condition is met, the temperature difference between the first pole ear 110 and the second pole ear 120 can be effectively reduced, avoiding affecting the temperature distribution of the battery and improving the performance of the battery. In addition, since the first pole ear 110 and the second pole ear 120 are relatively thin, increasing the width of the first pole ear 110 can greatly increase the surface area of the first pole ear 110, which is conducive to the rapid heat dissipation of the first pole ear 110, effectively reducing the temperature difference between the first pole ear 110 and the second pole ear 120, avoiding affecting the temperature distribution of the battery and improving the performance of the battery, so W1 only needs to be greater than or equal to 1.3W2. Further, W1≤10W2; if the width difference between W1 and W2 is too large, it will increase the difficulty of packaging and reduce the space utilization of the battery cell, so W1≤10W2 is limited.
[0026] Specifically, the thickness T1 of the first pole tab 110 is 0.1 mm to 0.3 mm, the width W1 of the first pole tab 110 is 3.9 mm to 100 mm, and the width W2 of the second pole tab 120 is 3 mm to 10 mm.
[0027] The embodiment of the present invention further provides a lithium-ion battery 100, comprising a battery cell body, a packaging bag, and a tab assembly as described in any one of the above, so as to have all the effects of the tab assembly. The battery cell body is contained in the packaging bag; one end of the first tab 110 is connected to the positive electrode of the battery cell body, and the other end extends out of the packaging bag; one end of the second tab 120 is connected to the negative electrode of the battery cell body, and the other end extends out of the packaging bag.
[0028] Furthermore, the packaging bag includes a bag body and a top seal portion connected to the bag body, the other end of the first pole ear 110 passes through the bag body and the top seal portion and then extends out of the packaging bag, and the other end of the second pole ear 120 passes through the bag body and the top seal portion and then extends out of the packaging bag; pole ear glue is bonded between the first pole ear 110 and / or the second pole ear 120 and the top seal portion.
[0029] An embodiment of the present invention further provides an electrical device, comprising a load and a lithium-ion battery 100 as in any of the above embodiments, wherein the lithium-ion battery 100 is used to supply power to the load.
[0030] The present application is further described below by taking the lithium-ion battery 100 as an example and combining specific embodiments. It should be understood that these embodiments are only used to illustrate the present application and are not used to limit the scope of the present application.
[0031] Example 1 The lithium-ion battery 100 in the embodiment of the present invention includes a battery cell body, a packaging bag, a first pole ear 110 and a second pole ear 120, the packaging bag includes a bag body and a top seal portion connected to the bag body, and the battery cell body is located in the bag body; one end of the first pole ear 110 is connected to the positive electrode of the battery cell body, and the other end passes through the bag body and the top seal portion and extends out of the packaging bag; one end of the second pole ear 120 is connected to the negative electrode of the battery cell body, and the other end passes through the bag body and the top seal portion and extends out of the packaging bag; pole ear glue is bonded between the first pole ear 110 and / or the second pole ear 120 and the top seal portion.
[0032] The first pole tab 110 is an aluminum pole tab with a width W1 of 6 mm and a thickness T1 of 0.3 mm. The second pole tab 120 is a copper-plated nickel pole tab with the same length as the first pole tab 110 , a width W2 of 6 mm and a thickness T2 of 0.2 mm.
[0033] The difference between Examples 2-8 and Comparative Examples 1-7 and Example 1 is that the width W1 and thickness T1 of the first electrode tab 110 and the material, width W2 or thickness T2 of the second electrode tab 120 are changed. The details are shown in Table 1: Table 1 Parameters of Examples 1-8 and Comparative Examples 1-7 Performance Testing The lithium-ion battery prepared above was subjected to the following performance tests: 1. Perform two charge and discharge cycles at 0.2C to confirm whether the battery capacity meets the minimum capacity requirement; 2. Charge the battery at 0.2C to the rated full voltage and 0.02C cut-off current; 3. Leave it for more than 4 hours after fully charged; 4. Take the battery and short-circuit it until it is fully discharged, and control the short-circuit impedance to 3mΩ; (Continuously monitor the surface temperature of the battery body and the temperature of the tabs during short-circuit; and observe whether the battery has bad faults such as smoking and fire) 5. Place the short-circuited battery cell on dry absorbent paper and let it stand for more than 12 hours, and confirm whether there is leakage from the absorbent paper. The passing standard is no fire, no explosion, no leakage, and the temperature of any part of the battery is ≤130℃. Fill in the test results obtained in Table 2.
[0034] Table 2 Performance test results From the test results in Table 2, we can see that: Comparative Example 1 is a conventional solution in the prior art. Compared with Comparative Example 1, in Examples 1 to 4, when the width W1 of the first pole ear 110 and the width W2 of the second pole ear are the same, the thickness of the first pole ear is increased, which can reduce the Joule heat of the battery short-circuit discharge process, so that the temperature of the battery in the 3mΩ short-circuit test does not exceed 130°C; and when the thickness of the first pole ear is increased to more than 1.5 times the thickness of the second pole ear, the temperature difference between the first pole ear 110, the second pole ear 120 and the battery body can be reduced, which is beneficial to delaying battery aging. When T1≥1.5T2 is satisfied, the temperature difference between the first pole ear 110, the second pole ear 120 and the battery body can be reduced, so the test effect of Example 4 is better, but due to the excessive difference in thickness between the first pole ear and the second pole ear, the packaging difficulty increases, which leads to poor flatness of the battery. Although Comparative Example 2 also increases the thickness of the first pole ear, the increase is less. Therefore, although the Joule heat of the battery short-circuit discharge process is reduced, the temperature of the battery in the 3mΩ short-circuit test still exceeds 130°C, causing the PP glue at the pole ear to melt, which in turn causes the battery to leak and fail the test.
[0035] Compared with Comparative Example 1, in Examples 5 to 8, when the thickness T1 of the first pole ear 110 is the same as the thickness T2 of the second pole ear 120, the width of the first pole ear is increased, which can reduce the Joule heat of the battery short-circuit discharge process, so that the temperature of the battery in the 3mΩ short-circuit test does not exceed 130°C; and, when the width of the first pole ear is increased to more than 1.3 times the width of the second pole ear, the temperature difference between the first pole ear 110, the second pole ear 120 and the battery body can be reduced, which is beneficial to delaying battery aging. When W1≥1.3W2 is satisfied, the temperature difference between the first pole ear 110, the second pole ear 120 and the battery body can be reduced, so the test effect of Example 8 is better, but because the width difference between the first pole ear and the second pole ear is too large, it is not conducive to the winding of the positive and negative electrodes, resulting in increased packaging difficulty and reduced battery space utilization. In Comparative Example 3, W1 is less than 1.3W2. Compared with Comparative Example 1, although the maximum temperature of the first pole ear is reduced, the reduction is limited, and the maximum temperature of the first pole ear is still higher than 130°C, which causes the PP glue at the pole ear to melt, and then causes the battery to leak and fail the test.
[0036] In Comparative Example 4, the thickness of the first pole ear is 1.5 times the thickness of the second pole ear, but the width of the first pole ear is reduced, resulting in a ratio of the cross-sectional area of the first pole ear to the cross-sectional area of the second pole ear of less than 1.3, which cannot significantly reduce its resistance, resulting in a large amount of heat generated by the first pole ear in the 3mΩ short-circuit test. Although the temperature is lower than that of Comparative Example 1, it still exceeds 130°C, and the battery leaks and fails the test. Similarly, in Comparative Example 5, the width of the first pole ear is 1.33 times the width of the second pole ear, but the thickness of the first pole ear is reduced, resulting in a ratio of the cross-sectional area of the first pole ear to the cross-sectional area of the second pole ear of less than 1.3, which in turn results in a higher temperature in the 3mΩ short-circuit test, resulting in battery leakage and failure to pass the test.
[0037] In Comparative Examples 6 and 7, although the thickness or width of the first pole ear is increased, the resistivity of nickel is large. Therefore, the nickel pole ear with the same length, width and thickness has a higher resistance, and generates more heat in the 3mΩ short-circuit test, so the temperature is high, causing the battery to catch fire and leak, and fail the test.
[0038] The embodiments described above are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included in the protection scope of the present invention.
Claims
1. A tab assembly, characterized in that: The invention comprises a first pole lug (110) and a second pole lug (120), wherein the first pole lug (110) is an aluminum pole lug and the second pole lug (120) is a copper-nickel-plated pole lug; and the ratio of the cross-sectional area of the first pole lug (110) to the cross-sectional area of the second pole lug (120) is greater than 1.
3.
2. The tab assembly according to claim 1, characterized in that: The width W1 of the first pole tab (110) is the same as the width W2 of the second pole tab (120), and the thickness T1 of the first pole tab (110) and the thickness T2 of the second pole tab (120) satisfy: T1≥1.5T2.
3. The tab assembly according to claim 2, characterized in that: T1≤3T2.
4. The tab assembly according to claim 3, characterized in that: The width W1 of the first electrode tab (110) is 3 mm to 100 mm; The thickness T1 of the first pole tab (110) is 0.15 mm to 0.6 mm, and the thickness T2 of the second pole tab (120) is 0.1 mm to 0.4 mm.
5. The tab assembly according to claim 1, characterized in that: The thickness T1 of the first pole tab (110) is the same as the thickness T2 of the second pole tab (120), and the width W1 of the first pole tab (110) and the width W2 of the second pole tab (120) satisfy: W1≥1.3W2.
6. The tab assembly according to claim 5, characterized in that: W1≤10W2.
7. The tab assembly according to claim 5, characterized in that: The thickness T1 of the first electrode tab (110) is 0.1 mm to 0.3 mm; The width W1 of the first pole tab (110) is 3.9 mm to 100 mm, and the width W2 of the second pole tab (120) is 3 mm to 10 mm.
8. A lithium ion battery, characterized in that: It comprises a battery cell body, a packaging bag and a pole ear assembly as claimed in any one of claims 1 to 7, wherein the battery cell body is accommodated in the packaging bag; one end of the first pole ear (110) is connected to the positive electrode of the battery cell body, and the other end extends out of the packaging bag; one end of the second pole ear (120) is connected to the negative electrode of the battery cell body, and the other end extends out of the packaging bag.
9. The lithium-ion battery according to claim 8, characterized in that: The packaging bag comprises a bag body and a top seal portion connected to the bag body, and the battery cell body is located in the bag body; the other end of the first pole lug (110) passes through the bag body and the top seal portion and then extends out of the packaging bag, and the other end of the second pole lug (120) passes through the bag body and the top seal portion and then extends out of the packaging bag; pole lug glue is bonded between the first pole lug (110) and / or the second pole lug (120) and the top seal portion.
10. An electrical device, characterized in that: It comprises a load and a lithium-ion battery (100) as claimed in claim 8 or 9, wherein the lithium-ion battery (100) is used to supply power to the load.