Lithium-ion battery cells and lithium-ion batteries.
Patent Information
- Application Number
- TH2503000997
- Authority / Receiving Office
- TH · TH
- Patent Type
- Utility models
- Current Assignee / Owner
- Priority Date
- 2022-09-23
- Filing Date
- 2023-07-27
- Publication Date
- 2026-02-05
- Estimated Expiration
- 2029-07-26
AI Technical Summary
Lithium-ion batteries can easily cause thermal runaway under conditions such as overcharge, rapid charge and discharge, short circuit, and high-temperature hot boxes, leading to safety issues, especially lithium precipitation on the negative electrode surface and damage to the crystal structure of the positive electrode material, which increases the risk of explosion.
An overcharge protective layer containing a tetravalent titanium compound is used, located between the negative electrode sheet and the separator. It is more oxidizing than lithium ions and can reduce the reaction before the negative electrode sheet during overcharging, thus preventing lithium ions from being over-reduced. Protect the negative electrode from short circuit and thermal runaway.
It effectively improves the thermal safety performance and overcharge performance of lithium-ion batteries, reduces the hazards of thermal runaway caused by overcharge, and significantly improves the safety performance of the battery.
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Abstract
Description
Lithium-ion cells and lithium-ion batteries
[0001] This application claims priority to the patent application submitted to the State Intellectual Property Office of China on September 23, 2022, with application number 202222529625.X and invention name "Lithium-ion battery cell and lithium-ion battery". Technical Field
[0002] The present application relates to the technical field of lithium-ion batteries, and in particular to a lithium-ion battery cell and a lithium-ion battery. Background Art
[0003] With the widespread use of lithium-ion batteries in recent years, electric vehicle explosions and fires in lithium-ion battery factories have occurred frequently, each bringing lithium-ion battery safety to the forefront. Besides external factors related to usage, the safety of lithium-ion batteries primarily depends on internal factors such as the electrochemical system and the structure, design, and production process of the electrodes / cells. The electrochemical system employed by the battery is the most fundamental factor in determining battery safety. Unsafe lithium-ion battery behaviors (overcharge, over-discharge, rapid charge and discharge, short circuits, mechanical abuse, high-temperature hot boxes, and heavy object impacts) can easily trigger dangerous side reactions within the battery, generating heat that directly damages the passivation films on the negative and positive electrode surfaces, potentially causing the battery temperature to rise and potentially leading to thermal runaway.
[0004] Among them, since the operating conditions of each single cell in the battery pack, such as current, voltage, and temperature, may be inconsistent during use, it is easier for a single battery to be overcharged. Overcharging of lithium-ion batteries will lead to many serious consequences, such as the destruction of the crystal structure of the positive electrode material, which will deteriorate the cycle life, aggravate the oxidation of the electrolyte on the positive electrode surface, and cause battery thermal runaway, as well as lithium deposition on the negative electrode, which will cause short circuit or thermal runaway and other safety issues. In this way, batteries without splints or whose safety valves cannot be opened normally increase the risk of explosion.
[0005] Summary of the Invention
[0006] The main purpose of this application is to provide a lithium-ion battery cell and a lithium-ion battery, wherein the lithium-ion battery cell has good battery thermal safety performance and overcharge performance.
[0007] In order to achieve the above-mentioned purpose, the present application provides a lithium-ion battery cell, including a battery cell unit, which includes: a positive electrode sheet; a negative electrode sheet; a diaphragm located between the negative electrode sheet and the positive electrode sheet to separate the positive electrode sheet and the negative electrode sheet; an overcharge protection layer capable of conducting electrons and ions, the overcharge protection layer is located between the negative electrode sheet and the diaphragm, and the overcharge protection layer is provided on at least one side of the diaphragm or the negative electrode sheet, and the oxidizing property of the overcharge protection layer is stronger than the oxidizing property of lithium ions.
[0008] Furthermore, the material of the overcharge protection layer contains a tetravalent titanium compound.
[0009] Furthermore, the tetravalent titanium compound is a granular material, and the D50 particle size of the tetravalent titanium compound is between 0.2 μm and 1 μm.
[0010] Furthermore, the tetravalent titanium-containing compound is any one of lithium aluminum titanium phosphate, lithium lanthanum titanate, lithium titanate, and titanium dioxide.
[0011] Furthermore, the negative electrode sheet includes a negative electrode current collector and negative electrode active material layers located on opposite sides of the negative electrode current collector. An overcharge protection layer is provided on a side of the negative electrode active material layer away from the negative electrode current collector.
[0012] Furthermore, a ratio of the thickness of the overcharge protection layer to the thickness of the diaphragm is greater than or equal to 0.1 and less than or equal to 0.6.
[0013] Furthermore, the ratio of the thickness of the overcharge protection layer to the thickness of the negative electrode sheet is greater than or equal to 0.005 and less than or equal to 0.05.
[0014] Furthermore, the thickness of the overcharge protection layer is greater than or equal to 1 μm and less than or equal to 4 μm.
[0015] Furthermore, the lithium-ion battery cell is formed by winding one or more battery cell units; or, the lithium-ion battery cell includes one or more battery cell units stacked in sequence.
[0016] According to another aspect of the present application, the present application provides a lithium-ion battery, which includes a shell, the above-mentioned lithium-ion battery cell located in the shell, and an electrolyte filled in the shell.
[0017] By applying the technical solution of the present application, when the battery is overcharged, the overcharge protection layer will undergo a reduction reaction before the lithium ions at the negative electrode sheet because the oxidizing property of the overcharge protection layer is stronger than that of lithium ions. That is, the overcharge protection layer will obtain electrons before the lithium ions at the negative electrode sheet. In this way, the lithium ions at the negative electrode sheet can be prevented from being reduced to a certain extent, so as to provide a certain degree of protection to the negative electrode sheet during overcharging, so as to avoid safety problems such as short circuit or thermal runaway caused by lithium precipitation on the surface of the negative electrode sheet. In this way, the voltage state of the battery will not continue to rise, and the problem of further damage to the crystal structure of the positive electrode sheet material can be avoided, thereby avoiding the problem of aggravating the oxidation of the electrolyte on the surface of the positive electrode sheet. Therefore, the lithium-ion battery cell of this embodiment has good battery thermal safety performance and overcharge performance, which can effectively alleviate the thermal runaway hazard that may be caused by overcharging of the battery, greatly reduce the risk of battery overcharge failure, and improve the safety performance of the lithium-ion battery. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The drawings that constitute part of this application are used to provide a further understanding of this application. The illustrative embodiments of this application and their descriptions are used to explain this application and do not constitute an improper limitation on this application. In the drawings:
[0019] FIG1 shows a schematic structural diagram of an overcharge protection layer coated on a diaphragm of a lithium-ion battery cell according to an embodiment of the present application;
[0020] FIG2 shows a schematic structural diagram of an overcharge protection layer coated on a negative electrode sheet of a lithium-ion battery cell according to an embodiment of the present application;
[0021] FIG3 shows a schematic structural diagram of an embodiment of a lithium-ion battery cell of the present application;
[0022] FIG4 shows a schematic structural diagram of another embodiment of a lithium-ion battery cell of the present application; and
[0023] FIG5 shows a voltage curve diagram of a continuous overcharge test of batteries in Example 1 and Comparative Example 1 of the present application.
[0024] The above drawings include the following reference numerals:
[0025] 10. Separator; 40. Overcharge protection layer; 50. Negative electrode active material layer; 60. Negative electrode current collector; 100. Positive electrode sheet; 300. Negative electrode sheet; 400. Positive electrode tab; 500. Negative electrode tab. DETAILED DESCRIPTION
[0026] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.
[0027] It should be noted that in the embodiments of the present application, when the battery is charging, lithium ions are released from the positive electrode, pass through the electrolyte, and then obtain electrons at the negative electrode for reduction and embedding into the negative electrode.
[0028] It should be noted that in the embodiments of the present application, preventing overcharging is extremely important for the safe use of lithium-ion batteries. Controlling the charging voltage is a commonly used overcharging protection measure for lithium-ion batteries. The change in the charging voltage of lithium-ion batteries is mainly caused by the positive electrode material being close to a completely delithiated state. However, it is generally difficult to detect the degree of completion of the negative electrode charging process at this time (because its lithium insertion potential is very close to that of metallic lithium). Therefore, as shown in Figures 1 and 2, the embodiments of the present application provide a lithium-ion battery cell. The lithium-ion battery cell includes a battery cell unit, which includes a positive electrode sheet 100, a negative electrode sheet 300, a separator 10, and an overcharge protection layer 40 capable of conducting electrons and ions. The diaphragm 10 is located between the negative electrode sheet 300 and the positive electrode sheet 100 to separate the positive electrode sheet 100 and the negative electrode sheet 300; the overcharge protection layer 40 is located between the negative electrode sheet 300 and the diaphragm 10, and the overcharge protection layer 40 is provided on at least one side of the diaphragm 10 or the negative electrode sheet 300. The oxidizing property of the overcharge protection layer 40 is stronger than that of lithium ions.
[0029] In the above technical solution, when the battery is overcharged, since the oxidizing property of the overcharge protection layer 40 is stronger than that of lithium ions, the overcharge protection layer 40 will undergo a reduction reaction before the lithium ions at the negative electrode sheet 300, that is, the overcharge protection layer 40 will obtain electrons before the lithium ions at the negative electrode sheet 300. In this way, the lithium ions at the negative electrode sheet 300 can be prevented from being reduced to a certain extent, so as to provide a certain degree of protection to the negative electrode sheet 300 during overcharging, so as to avoid safety problems such as short circuit or thermal runaway caused by lithium precipitation on the surface of the negative electrode sheet 300. In this way, the voltage state of the battery will not continue to rise, and the problem of further damage to the crystal structure of the positive electrode sheet 100 material can be avoided, thereby avoiding aggravating the oxidation of the electrolyte on the surface of the positive electrode sheet 100. Therefore, the lithium-ion battery cell of this embodiment has good battery thermal safety performance and overcharge performance, thereby effectively alleviating the thermal runaway hazard that may be caused by overcharging of the battery, greatly reducing the risk of battery overcharge failure, and improving the safety performance of the lithium-ion battery.
[0030] It should be noted that, in the embodiment of the present application, the overcharge protection layer 40 can conduct electrons and ions. In this way, the overcharge protection layer 40 does not affect the normal charging and discharging of the battery, but can protect the negative electrode sheet 300.
[0031] Specifically, in the embodiment of the present application, since the overcharge protection layer 40 obtains electrons before the lithium ions at the negative electrode sheet 300, the probability of forming lithium dendrites in the battery can be reduced.
[0032] Preferably, in the embodiment of the present application, the overcharge protection layer 40 is coated on the surface of the negative electrode sheet 300 or on the side of the separator 10 facing the negative electrode sheet 300 .
[0033] Specifically, in the embodiment of the present application, the material of the overcharge protection layer 40 is a tetravalent titanium compound. In this way, the oxidizing property of the overcharge protection layer 40 can be stronger than that of lithium ions, so that the overcharge protection layer 40 is reduced before lithium ions.
[0034] Preferably, in the embodiments of the present application, the tetravalent titanium-containing compound is any one of lithium aluminum titanium phosphate, lithium lanthanum titanate, lithium titanate, and titanium dioxide. These materials are not only more oxidizing than lithium ions but also have excellent thermal stability, effectively mitigating thermal runaway that may be caused by overcharging.
[0035] The above-mentioned tetravalent compound is a common and easily available compound, which can reduce the production cost of lithium-ion batteries.
[0036] It should be noted that in the embodiment of the present application, the material of the overcharge protection layer 40 is generally a material with good thermal stability that can undergo a valence change reaction with lithium ions at a low potential (<2V).
[0037] As shown in FIG2 , in an embodiment of the present application, the negative electrode sheet 300 includes a negative electrode current collector 60, a negative electrode active material layer 50 located on opposite sides of the negative electrode current collector 60, and an overcharge protection layer 40 is provided on the side of the negative electrode active material layer 50 facing away from the negative electrode current collector 60. With this arrangement, the overcharge protection layer 40 can effectively protect the negative electrode active material layer 50.
[0038] Specifically, in the embodiments of the present application, the ratio of the thickness of the overcharge protection layer 40 to the thickness of the separator 10 is greater than or equal to 0.1 and less than or equal to 0.6. Since the thicker the overcharge protection layer 40, the better its thermal stability, the above configuration can ensure that the overcharge protection layer 40 has good thermal stability without affecting the normal charging and discharging of the battery, thereby effectively improving the thermal safety performance of the battery.
[0039] Specifically, in the embodiment of the present application, the ratio of the thickness of the overcharge protection layer 40 to the thickness of the negative electrode sheet 300 is greater than or equal to 0.005 and less than or equal to 0.05. Since the thicker the overcharge protection layer 40, the better its thermal stability, the above configuration can ensure that the overcharge protection layer 40 has good thermal stability without affecting the normal charging and discharging of the battery, thereby effectively improving the thermal safety performance of the battery.
[0040] Preferably, in the embodiment of the present application, the thickness of the overcharge protection layer 40 is greater than or equal to 1 μm and less than or equal to 4 μm. Such thickness can make the overcharge protection layer 40 have good thermal stability, thereby effectively improving the thermal safety performance of the battery.
[0041] Preferably, in the embodiment of the present application, the tetravalent titanium compound is a granular material, and the D50 particle size of the tetravalent titanium compound is between 0.2 μm and 1 μm. This can increase the thermal stability of the overcharge protection layer 40, thereby effectively improving the thermal safety performance of the battery.
[0042] As shown in Figure 3, in an embodiment of the present application, the lithium-ion battery cell is formed by winding one or more battery units; or, as shown in Figure 4, in an embodiment of the present application, the lithium-ion battery cell comprises one or more battery units stacked in sequence. In this way, the lithium-ion battery cell can be applied to both cylindrical and prismatic batteries.
[0043] As shown in FIG. 4 , in the embodiment of the present application, the battery cell unit further includes a positive electrode tab 400 connected to the positive electrode sheet 100 , and a negative electrode tab 500 connected to the negative electrode sheet 300 .
[0044] Example 1
[0045] The separator 10 uses a 12μm thick PE-based film (polyethylene film), and a 3μm thick lithium titanium aluminum phosphate coating is applied to the side of the separator 10 facing the negative electrode sheet 300. The particle size D50 of the lithium titanium aluminum phosphate coating is 0.7μm and the purity is 99.95%. The positive electrode sheet uses a 622 type ternary positive electrode material, and the negative electrode sheet uses a graphite material. After matching the electrolyte, a 10Ah soft-pack battery is trial-produced. The battery after capacity is divided and charged using a 20A constant current to 3.6V, then switched to constant voltage charging. Charging is stopped when the charging current drops to 1A and the battery is left for 1 hour. Then, charging is continued at a 20A constant current until charging stops at 20V. The battery is observed for 1 hour, and the battery voltage change is monitored during the test.
[0046] Comparative Example 1
[0047] The separator 10 uses a 12μm thick PE-based film (polyethylene film). A 3μm thick alumina ceramic coating is applied to the side of the separator 10 facing the negative electrode 300. The alumina ceramic coating has a particle size D50 of 0.7μm and a purity of 99.95%. The positive electrode uses a 622-type ternary positive electrode material, and the negative electrode uses a graphite material. A 10Ah soft-pack battery is produced with the matching electrolyte. After the battery is divided into capacities, it is charged using a 20A constant current to 3.6V and then switched to constant voltage charging. Charging is stopped when the charging current drops to 1A and the battery is left for 1 hour. Then, charging is continued at a 20A constant current until it reaches 20V. The battery is observed for 1 hour, and the battery voltage change is monitored during the test.
[0048] Example 2
[0049] The separator 10 is made of a 9μm thick PE-based film (polyethylene film). A 4μm thick lithium lanthanum titanium oxide coating is applied to the side of the separator 10 facing the negative electrode 300. The particle size D50 of the lithium lanthanum titanium oxide coating is 0.4μm and the purity is 99.92%. The positive electrode 100 is made of lithium iron phosphate material, and the negative electrode is made of graphite material. The electrolyte is matched to produce a 10Ah cylindrical battery. After the battery is divided into capacities, it is charged with a constant current of 5A to 3.2V and then switched to constant voltage charging. Charging is stopped when the charging current drops to 0.1A and the battery is left for 1 hour. Then, charging is continued with a constant current of 2A until it reaches 5V. The battery is observed for 1 hour, and the battery voltage change is monitored during the test.
[0050] Comparative Example 2
[0051] The separator 10 is made of a 9μm-thick PE-based film (polyethylene film). A 4μm-thick boehmite ceramic coating is applied to the side of the separator 10 facing the negative electrode 300. The boehmite ceramic coating has a particle size D50 of 0.4μm and a purity of 99.92%. The positive electrode is made of lithium iron phosphate, and the negative electrode is made of graphite. A 10Ah cylindrical battery is produced using the matching electrolyte. After the battery is divided into capacities, it is charged using a 5A constant current to 3.2V, then switched to constant voltage charging. Charging is stopped when the charging current drops to 0.1A and the battery is left for 1 hour. Charging is then continued at a 2A constant current until it reaches 5V. The battery is observed for 1 hour, and the voltage change is monitored during the test.
[0052] Example 3
[0053] The negative electrode sheet is made of graphite and coated with a 2μm thick titanium dioxide coating. The particle size D50 of the titanium dioxide coating is 0.8μm and the purity is 99.90%. The positive electrode sheet uses 622 ternary positive electrode material, and the separator 10 is used and matched with the electrolyte to trial-produce a 20Ah soft-pack battery. After the battery is divided into capacities, it is charged using a 10A constant current to 3.6V and then switched to constant voltage charging. Charging is stopped when the charging current drops to 0.05A and the battery is left for 1 hour. Then, the constant current charging is continued at 10A until the charging voltage reaches 10V. The battery is observed for 1 hour, and the battery voltage change is monitored during the test.
[0054] Comparative Example 3
[0055] The negative electrode sheet was made of graphite and coated with a 2μm-thick alumina ceramic coating. The particle size D50 of the alumina ceramic coating was 0.8μm and the purity was 99.90%. The positive electrode sheet used 622 ternary positive electrode material, a separator 10, and a matching electrolyte to produce a 20Ah soft-pack battery. After the battery was divided into capacities, it was charged using a 10A constant current to 3.6V, then switched to constant voltage charging. Charging was stopped when the charging current dropped to 0.05A and the battery was left for 1 hour. The battery was then charged at a 10A constant current until it reached 10V. The battery was observed for 1 hour, and the battery voltage change was monitored during the test.
[0056] Example 4
[0057] The negative electrode was made of graphite and coated with a 5μm-thick lithium titanate coating with a particle size D50 of 0.5μm and a purity of 99.94%. A 50Ah square aluminum-cased battery was manufactured using lithium iron phosphate as the positive electrode, a separator 10, and a matching electrolyte. After the battery was fully charged, it was charged at a constant current of 50A to 3.2V, then switched to constant voltage charging. Charging was stopped when the charging current dropped to 2A and the battery was left standing for 1 hour. Charging was then continued at a constant current of 50A until it reached 5V. The battery was then observed for 1 hour, and the voltage change was monitored during the test.
[0058] Comparative Example 4
[0059] The negative electrode was made of graphite and coated with a 5μm-thick silica ceramic coating. The silica ceramic coating had a particle size D50 of 0.5μm and a purity of 99.94%. A 50Ah square aluminum-cased battery was manufactured using lithium iron phosphate as the positive electrode, a separator 10, and a matching electrolyte. After the battery was fully charged, it was charged at a constant current of 50A to 3.2V, then switched to constant voltage charging. Charging was stopped when the charging current dropped to 2A and the battery was left standing for 1 hour. Charging was then continued at a constant current of 50A until it reached 5V. The battery was then observed for 1 hour, and the voltage change was monitored during the test.
[0060] The continuous overcharge test data of the batteries of Examples 1 to 4 and Comparative Examples 1 to 4 are shown in Table 1.
[0061] Table 1 Battery continuous overcharge test results
[0062] As can be seen from Table 1 and Figure 5, when the battery of the comparative example is continuously overcharged according to the test conditions, the crystal structure of the positive electrode material inside the battery may be destroyed, and the oxidation reaction of the electrolyte on the positive electrode surface may be intensified. Lithium deposition may also occur on the negative electrode surface to form lithium dendrites, and the solid electrolyte film formed on the negative electrode surface may also undergo continuous reaction. The above reactions lead to the accumulation of heat inside the battery, causing the battery temperature to exceed 350°C, thereby further causing thermal runaway of the battery.
[0063] Compared with the comparative example, the battery of the present embodiment was tested under the continuous overcharge test conditions, and the test voltage did not reach the set voltage parameters. Therefore, during the battery overcharge process, the overcharge protection layer coated on the surface of the negative electrode sheet or the side of the diaphragm facing the negative electrode sheet can be reduced before the lithium ions obtain electrons (that is, the overcharge protection layer and the lithium ions undergo a reduction reaction). In this way, the voltage difference inside the battery can be reduced to avoid safety problems such as short circuit or thermal runaway caused by lithium precipitation on the surface of the negative electrode sheet. It can also avoid aggravating the oxidation reaction on the positive electrode surface and avoid the accumulation of heat inside the battery, so that the internal temperature of the battery is less than 120°C. Therefore, the battery of this embodiment has good thermal safety performance and overcharge performance, can effectively alleviate the thermal runaway hazard of the battery caused by overcharging, greatly reduce the risk of battery overcharge failure, and improve the safety performance of the lithium-ion battery.
[0064] Embodiments of the present application provide a lithium-ion battery. The lithium-ion battery comprises a housing, the aforementioned lithium-ion battery cell located within the housing, and an electrolyte filled within the housing. The aforementioned lithium-ion battery has all the advantages of the aforementioned lithium-ion battery cell and will not be further elaborated here.
[0065] From the above description, it can be seen that the above-mentioned embodiments of the present application achieve the following technical effects: when the battery is overcharged, since the oxidizing property of the overcharge protection layer is stronger than the oxidizing property of lithium ions, the overcharge protection layer will undergo a reduction reaction before the lithium ions at the negative electrode sheet, that is, the overcharge protection layer will obtain electrons before the lithium ions at the negative electrode sheet. In this way, the lithium ions at the negative electrode sheet can be prevented from being reduced to a certain extent, so as to provide a certain degree of protection to the negative electrode sheet during overcharging, so as to avoid safety problems such as short circuit or thermal runaway caused by lithium precipitation on the surface of the negative electrode sheet. In this way, the voltage state of the battery will not continue to rise, and the problem of further damage to the crystal structure of the positive electrode sheet material can be avoided, thereby avoiding aggravating the oxidation of the electrolyte on the surface of the positive electrode sheet. Therefore, the lithium-ion battery cell of this embodiment has good battery thermal safety performance and overcharge performance, thereby effectively alleviating the thermal runaway hazard that may be caused by overcharging of the battery, greatly reducing the risk of battery overcharge failure, and improving the safety performance of the lithium-ion battery.
[0066] The above description is merely a preferred embodiment of the present application and is not intended to limit the present application. Various modifications and variations are possible for those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.
Claims
DEPCT68 1. A lithium-ion battery cell is composed of battery cell units, in which the unit... A battery cell consists of: Positive electrode plate (100), Negative electrode plate (300), The separator (10) is placed between the negative electrode plate (300) and the positive electrode plate (100) in order to Separate the positive electrode plate (100) from the negative electrode plate (300) and Overcharge protection layer (40) which can conduct electrons and ions, where the protective layer The overcharge (40) is located between the negative electrode (300) and the separator (10) and is positioned on the plate. One side of the separator (10) or negative electrode plate (300) and the oxidizing ability of the layer Prevents overcharging (40) Higher than the oxidizing capacity of lithium ions.
2. Lithium-ion battery cells according to claim 1, where the material of the protective layer against charging is present. Too much (40) is a titanium compound in the tetravalent state.
3. Lithium-ion battery cells according to claim 2, in which titanium compounds are used. In the tetravalent state, it is a fine-grained material, and the particle size D50 of the titanium compound in... The tetravential property is between 0.2 micrometers and 1 micrometer.
4. Lithium-ion battery cells under claim 2, in which titanium compounds are used. In the tetravalent state, it is one of the compounds of lithium aluminum titanium phosphate. Lithium lanthanum titanium oxide, lithium titanate, and titanium dioxide.
5. A lithium-ion battery cell as described in any of the claims 1-4, in which the plates The negative electrode (300) is composed of a negative electrode current collector (60) and an active material layer. Negative electrode (50) located on two opposite sides of the negative electrode (60) current collector protective layer The overcharge (40) is placed on the sides of each facing negative electrode active material layer (50). Face out of negative electrode current collector (60) 6. A lithium-ion battery cell as described in any of the claims 1-4, where the ratio... The thickness of the overcharge protection layer (40) versus the thickness of the isolator (10) is greater or less. Equal to 0.1 and less than or equal to 0.
6.
7. A lithium-ion battery cell as described in any of the claims 1-4, where the ratio... The thickness of the overcharge protection layer (40) versus the thickness of the negative electrode plate (300). Greater than or equal to 0.005 and less than or equal to 0.
05.
8. A lithium-ion battery cell as described in any of the claims 1-4, where the thickness The overcharge protection layer (40) is greater than or equal to 1 micrometer and less than or equal to 4. micrometer 9. A lithium-ion battery cell as described in any of the claims 1-4, where the cell Lithium-ion batteries are formed by winding one or more battery cell units together. A lithium-ion battery cell consists of one or more battery cell units which are... Stacked in layers according to sequence.
10. Lithium-ion battery consisting of a housing and lithium-ion battery cells. As per any one of the claims 1-9 contained within the casing and the electrolyte contained within the casing.