Lithium-ion batteries, battery packs, electric vehicles and energy storage devices

Abstract

To provide a lithium ion battery, a power battery module, a battery pack, an electric vehicle, and an energy storage device that can effectively solve the problem of thermal runaway and improve the safety of use.SOLUTION: A lithium ion battery includes a case and an electrode body sealed in the case, the electrode body includes a positive electrode sheet, a negative electrode sheet, and a separator located between the positive electrode sheet and the negative electrode sheet, the positive electrode sheet includes a positive electrode current collector and a positive electrode material layer supported on the positive electrode current collector, and among the positive electrode current collector, the positive electrode material layer, the negative electrode sheet, and the separator, the one having the lowest melting point is defined as an active component, and the active component satisfies the condition of the following formula.SELECTED DRAWING: None

Description

[Technical Field]

[0001] This application relates to the technical field of lithium ion batteries, and in particular to lithium ion batteries, battery packs, electric vehicles and energy storage devices. [Background technology]

[0002] Due to their unique characteristics, lithium-ion batteries are being applied in an ever-increasing number of fields, with power batteries in particular experiencing rapid development. When lithium batteries are used as the primary energy source for electric vehicles, particularly in recent years, due to the widespread use of ternary batteries, lithium-ion power batteries can experience thermal runaway (a chain reaction of heat generated by the battery, resulting in a rapid change in the rate of battery temperature rise, resulting in overheating, fire, or explosion), which can lead to fire and explosion accidents. In a battery pack, once one battery experiences thermal runaway, it will inevitably trigger thermal runaway in adjacent batteries in the battery pack or battery system, i.e., thermal diffusion, causing the entire battery pack to go out of control, resulting in serious consequences such as fire and explosion. Currently, lithium-ion batteries still face challenges in terms of their safety. Summary of the Invention

[0003] The present application seeks to at least partially solve one of the technical problems in the related art, and therefore, one objective of the present application is to provide a lithium-ion battery that can effectively solve the problem of thermal runaway and improve the safety of use.

[0004] In one aspect, the present application provides a lithium-ion battery, according to an embodiment of the present application, comprising a case and an electrode assembly sealed in the case, the electrode assembly comprising a positive electrode sheet, a negative electrode sheet, and a separator positioned between the positive electrode sheet and the negative electrode sheet, the positive electrode sheet comprising a positive electrode current collector and a positive electrode material layer carried on the positive electrode current collector, the positive electrode current collector, the positive electrode material layer, the negative electrode sheet, and the separator, the one having the lowest melting point is defined as an active component, and the active component satisfies the following conditions:

number

[0005] According to another aspect of the present application, the present application provides a lithium ion battery, the lithium ion battery including a case and an electrode assembly sealed in the case, the electrode assembly including a positive electrode sheet, a negative electrode sheet, and a separator positioned between the positive electrode sheet and the negative electrode sheet, the positive electrode sheet including a positive electrode current collector and a positive electrode material layer carried on the positive electrode current collector, and the positive electrode current collector satisfies the following conditions:

number

[0006] In another aspect, the present application provides a battery pack. According to an embodiment of the present application, the power battery module or battery pack includes at least one lithium ion battery as described above. The possibility of thermal runaway and thermal diffusion occurring in the battery pack is significantly reduced, and the safety of use is significantly improved.

[0007] In a further aspect, the present application provides an electric vehicle or energy storage device. According to an embodiment of the present application, the electric vehicle or energy storage device includes the battery pack described above. The electric vehicle has excellent safety and a long service life. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic diagram illustrating the configuration of a laminated electrode body according to an embodiment of the present invention. [Figure 2] FIG. 2 is a schematic cross-sectional view of the positive electrode sheet taken along line AA in FIG. [Figure 3] 1 is a schematic diagram illustrating the structure of a laminate constituting a wound electrode body according to an embodiment of the present invention in an unfolded state. [Figure 4] 1 is a schematic diagram of a wound electrode body according to an embodiment of the present invention; [Figure 5] 1 is a schematic diagram of a wound electrode body according to an embodiment of the present invention; [Figure 6] FIG. 6 is a schematic plan view of one winding portion in FIGS. 4 and 5. [Figure 7] FIG. 7 is a schematic cross-sectional view taken along line BB in FIG. 6. [Figure 8] FIG. 10 is a schematic plan view of one winding section of another embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0009] The examples of the present application are described in detail below. The examples described below are illustrative and are used to interpret the present application, but should not be understood as limiting the present application. Specific techniques or conditions are not specified in the examples, and the techniques or conditions are performed according to the techniques or conditions described in the literature in this field or according to the product specifications. The reagents and equipment used are all conventional products that are commercially available, although the manufacturers are not specified.

[0010] In one aspect, the present application provides a lithium-ion battery, according to an embodiment of the present application, comprising: a case; and an electrode assembly sealed in the case, the electrode assembly comprising a positive electrode sheet, a negative electrode sheet, and a separator positioned between the positive electrode sheet and the negative electrode sheet, the positive electrode sheet comprising a positive electrode current collector and a positive electrode material layer carried on the positive electrode current collector, wherein the active component is defined as the component having the lowest melting point among the positive electrode current collector, the positive electrode material layer, the negative electrode sheet, and the separator, and the active component satisfies the following conditions:

number

[0011] In some embodiments, the effective member satisfies the following conditions:

number

[0012] This further improves the safety of the lithium ion battery and further reduces the probability of thermal runaway and thermal diffusion occurring.

[0013] Specifically, the inventors of the present application carried out rational design and optimization based on the following two equations and models to obtain the lithium ion battery of the present application, which is specifically as follows: Based on the general heat balance equation:

number

number

[0014] The one-dimensional heat diffusion model is as follows:

number

[0015] Based on the above equations and models, combined with the inventor's practical research experience, and in accordance with the following principles, the inventor submits the present application: Thermal runaway is often caused by a short circuit inside the battery, and when a short circuit occurs, the temperature at the short circuit point can rise rapidly, causing thermal runaway in the battery and making it more likely to ignite or explode. In the lithium-ion battery of the present application, by controlling parameters such as the dimensions and thermodynamics of the active components in the battery, the short circuit point can be quickly melted and disconnected when the battery is short-circuited, preventing further heat generation and ensuring that the materials do not reach the runaway point, thereby greatly ensuring the safety of the battery, further avoiding the occurrence of thermal runaway, and greatly improving the safety of the battery.

[0016] Specifically, the lithium ion battery of the present application may be a liquid battery, a solid battery, or a polymer battery, and the liquid battery and the polymer battery may include a positive electrode sheet, a negative electrode sheet, and a separating film (i.e., a separator) located between the positive electrode sheet and the negative electrode sheet, and it is understood that the electrode body further includes an electrolyte solution, and the solid battery includes a positive electrode sheet, a negative electrode sheet, and a solid electrolyte layer (i.e., a separator) located between the positive electrode sheet and the negative electrode sheet.

[0017] In some examples, the negative electrode sheet may include a negative electrode current collector and a negative electrode material layer supported on the negative electrode current collector, and in such embodiments, the active component is defined as the component having the lowest melting point among the positive electrode current collector, the positive electrode material layer, the negative electrode current collector, the negative electrode material layer, and the separator.

[0018] In other examples, the negative electrode sheet may be a lithium foil or a lithium ribbon, and in such embodiments, the active component is defined as the component having the lowest melting point among the positive electrode current collector, the positive electrode material layer, the lithium foil (or the lithium ribbon), and the separator.

[0019] In some further embodiments, the negative electrode sheet may include a porous current collector and a negative electrode active material deposited on the porous current collector. In such embodiments, the active component is defined as the component having the lowest melting point among the positive electrode current collector, the positive electrode material layer, the porous current collector, and the separator.

[0020] Furthermore, the positive electrode sheet and the negative electrode sheet are provided with positive electrode tabs and negative electrode tabs for drawing out current, respectively. Specifically, the positive electrode tabs and negative electrode tabs are drawn out from one side of the positive electrode sheet and the negative electrode sheet, respectively. The positive electrode tabs and negative electrode tabs may be placed on the same side (see FIG. 8) or opposite each other (see FIGS. 1 and 7), and the drawing direction of the tabs is the drawing direction of the current.

[0021] In the electrode body, a plurality of positive electrode sheets 10 and negative electrode sheets 20 are alternately stacked in order to form a laminated electrode body (see FIG. 1 for a schematic diagram), and a separator may be placed between adjacent positive electrode sheets and negative electrode sheets, or the positive electrode sheets, separators, and negative electrode sheets may be stacked and then wound to form a wound electrode body (see FIG. 2 for a schematic diagram). Specific methods can all be implemented with reference to conventional technology, and therefore, a description thereof will be omitted here.

[0022] 1, the laminated electrode body specifically includes a plurality of positive electrode sheets 10 and negative electrode sheets 20 stacked alternately, with a separator (not shown) disposed between adjacent positive electrode sheets 10 and negative electrode sheets 20. In this case, L is the dimension of one effective member in the first direction, W is the dimension of one effective member in the second direction, and d2 is the thickness of one effective member (the dimension along the stacking direction).

[0023] Specifically, for the wound electrode body, as shown in Figures 3, 4, 5, 6, and 7, the positive electrode sheet 10, the negative electrode sheet 20, and the separator 40 are stacked and then wound. Specifically, the positive electrode sheet 10, the separator 40, and the negative electrode sheet 20 stacked in order are defined as a laminate 30. The laminate 30 is divided into a plurality of wound sections 31 (see Figure 3) that are connected in order. When in a wound state, the plurality of wound sections 31 are stacked in order (see Figure 4). In this case, L is the dimension in the first direction of the effective member in one wound section, W is the average value of the dimensions in the second direction of the effective members in the plurality of wound sections, and d2 is the thickness of the effective member in one wound section.

[0024] In addition, the second direction described in this specification intersecting with the first direction specifically means that the angle between the first direction and the second direction may be greater than 0 degrees and less than or equal to 90 degrees, and in some specific embodiments, the angle between the first direction and the second direction may specifically be 90 degrees, i.e., the first direction may be perpendicular to the second direction.

[0025] Specifically, the common materials used for the components of lithium-ion batteries generally have a low melting point for the positive electrode current collector, which prevents the electrode material from running away when the positive electrode current collector melts during thermal runaway, thereby significantly ensuring battery safety. Among the various short-circuiting events that can cause thermal runaway, such as a short circuit between the positive electrode material and the negative electrode material, a short circuit between the positive electrode current collector and the negative electrode sheet, or a short circuit between the negative electrode current collector and the positive electrode sheet, the greatest amount of heat is generated when the positive electrode current collector and the negative electrode material come into contact and short-circuit. Experiments have shown that a short circuit can rapidly increase the temperature at the short circuit point to 200°C, causing material runaway and potentially ignition or explosion. In the lithium-ion battery disclosed herein, the basic goal is to ensure that the material does not reach the runaway point when the short circuit melts. By selecting the positive electrode current collector as the active component, thermal runaway and thermal diffusion can be effectively avoided, significantly improving the safety of the battery.

[0026] The solution of the present invention will be described in more detail below, taking the positive electrode current collector as the active member.

[0027] According to an embodiment of the present application, as shown in FIGS. 1 and 2 , a positive electrode tab 11 is further drawn out from one side of the positive electrode sheet 10. Specifically, the direction in which the positive electrode tab is drawn out is the direction in which a current is drawn out from the positive electrode current collector. Therefore, in this case, the first direction is parallel to the direction in which the positive electrode tab is drawn out.

[0028] Specifically, the positive electrode tab may be welded to the positive electrode current collector or cut out from the positive electrode current collector; that is, the positive electrode tab and the positive electrode current collector may be integrally molded. Regardless of how the positive electrode tab is pulled out from the positive electrode current collector, the dimension of the positive electrode current collector along the first direction does not include the dimension of the positive electrode tab along the first direction. It should be understood that the situation of the negative electrode tab may be the same as that of the positive electrode tab, and therefore, a description thereof will be omitted here. Furthermore, the second direction may be selected according to actual circumstances. In some specific embodiments, the second direction is perpendicular to the first direction. This provides a higher degree of conformance to the above conditions, a lower probability of thermal runaway and thermal diffusion, and improved battery safety.

[0029] In some embodiments, as shown in FIGS. 1 and 2 , the electrode assembly in a lithium ion battery may be a laminated electrode assembly, and the laminated electrode assembly includes a plurality of positive electrode sheets 10 and negative electrode sheets 20 that are alternately stacked, where L is the dimension of the positive electrode current collector 12 in one positive electrode sheet 10 in the first direction, W is the dimension of the positive electrode current collector 12 in one positive electrode sheet 10 in the second direction, and d2 is the thickness of the positive electrode current collector 12 in one positive electrode sheet 10, and in the electrode assembly shown in FIGS. 1 and 2 , L, W, and d2 are as shown in the figures.

[0030] In some other embodiments, the electrode body in the lithium ion battery may be a wound electrode body. As shown in FIGS. 3 to 7, the wound electrode body is configured by winding a laminate 30 divided into a plurality of wound sections 31 that are connected in order. In the wound electrode body, the plurality of wound sections 31 are stacked and disposed, and each of the wound sections 31 includes a positive electrode sheet 10, a separator 40, and a negative electrode sheet 20 that are stacked and disposed in order. where W is the dimension of the positive electrode current collector 12 in one of the wound portions 31 in the first direction, L is the dimension of the positive electrode current collector 12 in one of the wound portions 31 in the second direction, W is the average value of the dimensions of the positive electrode current collector 12 in the multiple wound portions 31 in the second direction, and d2 is the thickness of the positive electrode current collector 12 in one of the wound portions 31. Specifically, in the wound electrode body shown in Figures 3 to 7, W = (W1 + W2 + W3 + W4 + W5) / 5, and L is as shown in the figures.

[0031] In some embodiments, the material of the positive electrode current collector is aluminum, for example, aluminum foil, and the material of the negative electrode current collector is copper foil. By rationally designing the battery parameters (such as the number of layers of the active components, dimensions in different directions, thickness, and specific heat capacity), aluminum, combined with its low melting point, can effectively ensure that the material will not go out of control when a short circuit occurs. This avoids thermal runaway and thermal diffusion, and greatly ensures the safety of lithium-ion batteries.

[0032] In some specific embodiments, the thickness d2 of the positive electrode current collector may be in the range of 6 μm to 15 μm (specifically, for example, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, etc.), and the density ρ of the positive electrode current collector may be in the range of 2000 kg m -3 ~3000kg m -3 (specifically, for example, 2000 kg m -3 , 2100 kg m -3 , 2200 kg m -3 , 2300 kg m -3 , 2400 kg m -3 , 2500 kg m -3 , 2600 kg m -3 , 2700 kg m -3 , 2800 kg m -3 , 2900 kg m -3 , 3000 kg m -3 ) and the specific heat capacity C of the positive electrode current collector p The range of values ​​is 800J·kg -1 °C -1 ~900J·kg -1 °C -1 (specifically, for example, 800 J kg -1 °C -1 , 810J·kg -1 °C -1 , 820J·kg -1 °C -1 , 830J·kg -1 °C -1 , 840J·kg -1 °C -1 , 850J·kg -1 °C -1 , 860J·kg -1 °C -1 , 870J·kg -1 °C -1 , 880J·kg -1 °C -1 , 890J·kg -1 °C -1 , 900J·kg -1 °C -1 Specifically, d2, ρ, C pis the thermal property of the positive electrode current collector. The larger the product of these three factors, the less likely the short circuit point will melt and the greater the risk of runaway. However, by keeping it within the above range, it is possible to effectively ensure that the material will not go out of control when the short circuit point melts, thereby better ensuring the safety of the battery.

[0033] In some specific embodiments, the ratio L / w of the dimension L of the positive electrode current collector in the first direction to the dimension W of the positive electrode current collector in the second direction is between 0 and 30 (specifically, for example, 1, 2, 5, 8, 10, 12, 15, 18, 20, 22, 25, 28, 30, etc.). L / w determines the ohmic resistance within the battery; the larger L / w, the greater the ohmic resistance and the greater the heat generated by the battery. L / w also determines the resistance of the positive electrode current collector; the greater the value, the greater the total heat generated until the electrode assembly melts at the short-circuit point and the greater the risk of runaway. By keeping the ratio within the above range, normal battery operation can be ensured, the risk of runaway is low, and by controlling the amount of heat generated within a certain range, damage to adjacent batteries or the outside due to the heat generated by the battery can be avoided.

[0034] In some specific embodiments, the specific types of the positive electrode material layer and the negative electrode active material in the lithium-ion battery of the present application are not particularly limited and can be flexibly selected and adjusted according to actual needs by those skilled in the art. In some specific embodiments, the positive electrode material layer may include a lithium iron phosphate material. In some specific embodiments, the negative electrode sheet includes a negative electrode active material that may include at least one of graphite, soft carbon, hard carbon, carbon fiber, mesocarbon microbeads, silicon-based materials, tin-based materials, and lithium titanate. This provides a higher degree of compatibility with the thermal runaway conditions and reduces the risk of thermal runaway in the lithium-ion battery.

[0035] In some specific embodiments, the lithium ion battery may be a rectangular battery, and the length of the lithium ion battery may be 500 mm to 2500 mm (specifically, for example, 500 mm, 800 mm, 1000 mm, 1500 mm, 1800 mm, 2000 mm, 2200 mm, 2500 mm, etc.). Specifically, the lithium ion battery may have a case (preferably a metal case) with a certain strength. A lithium ion battery within this shape and size range is more compatible with the thermal runaway conditions, and can be accurately controlled based on the thermal runaway conditions to reduce the risk of thermal runaway.

[0036] As can be understood, in addition to the components described above, the lithium ion battery may further include structures and components necessary for conventional lithium ion batteries, such as an electrolyte or solid electrolyte, necessary connecting wiring, etc., and specific details can all be made by referring to conventional techniques, so further description will be omitted here.

[0037] In some specific embodiments, the case contains a plurality of electrode bodies, which are divided into a plurality of electrode body groups connected in series. Specifically, for example, if the case contains 15 electrode bodies, each group containing five electrode bodies, the case contains three electrode body groups connected in series.

[0038] In some specific embodiments, a sealing film is further installed between the case and the electrode body, and the electrode body is sealed in the sealing film, which can better protect the electrode body, avoid problems such as breakage, improve the safety of the battery, and extend the service life of the battery.

[0039] In another aspect of the present application, the present application provides a lithium-ion battery. According to an embodiment of the present application, the lithium-ion battery includes a case and an electrode assembly sealed in the case, the electrode assembly includes a positive electrode sheet, a negative electrode sheet, and a separator positioned between the positive electrode sheet and the negative electrode sheet, the positive electrode sheet includes a positive electrode current collector and a positive electrode material layer carried on the positive electrode current collector, and the positive electrode current collector satisfies the following conditions:

number

[0040] As can be appreciated, the case, positive electrode sheet, negative electrode sheet, and separator of the lithium ion battery may all be the same as those described above, and will not be described again here.

[0041] In another aspect, the present application provides a power battery module, which, according to an embodiment of the present application, includes at least one lithium ion battery as described above, and the power battery module has significantly reduced thermal runaway and thermal diffusion, thereby significantly improving its safety in use.

[0042] Specifically, in the power battery module, multiple lithium ion batteries may be connected in series, parallel, or a combination thereof, or some lithium ion batteries may be connected to form a module, and multiple modules may be further connected to form a power battery module. Naturally, specific design and selection can be made according to actual needs, and no further explanation will be given here.

[0043] In a further aspect, the present application provides a battery pack. According to an embodiment of the present application, the battery pack includes at least one of the above-described lithium-ion battery or the above-described power battery module. The battery pack has high usage safety and a long service life.

[0044] In a further aspect, the present application provides an electric vehicle. According to an embodiment of the present application, the electric vehicle includes the power battery module or the battery pack described above. The electric vehicle has excellent safety and a long service life.

[0045] As can be understood, in addition to the power battery module described above, the electric vehicle may further include structures and components required for conventional electric vehicles, such as a body, tires, a motor, a frame, an interior, etc., which can be specifically implemented based on conventional technology and will not be described here.

[0046] In another aspect, the present application provides an energy storage device. According to an embodiment of the present application, the energy storage device includes the power battery module or the battery pack described above. The energy storage device has a significantly reduced probability of thermal runaway and thermal diffusion, and has excellent safety and a long service life. The embodiment of the present application is described in detail below.

[0047] In the following examples and comparative examples, a power battery module is used, which is formed by connecting a plurality of lithium ion batteries in series, and each lithium ion battery is a stacked battery, the positive electrode current collector is aluminum foil, the positive electrode material is lithium iron phosphate material, the negative electrode current collector is copper foil, the negative electrode material is graphite, the separator is polyolefin separator film, the electrolyte is lithium hexafluorophosphate organic electrolyte, and the lithium ion battery is a rectangular battery with a length of 1000 mm.

[0048] Performance test: The nail penetration test is carried out in accordance with the method of "GB / T 31485-2015 Safety requirements and test methods for power batteries for electric vehicles", and the specific nail penetration procedure is as follows:

[0049] Charging: At room temperature, the battery cells were first discharged at a current of 1C+0.2C to an end voltage of 2.0V, left for 30 minutes, and then charged at a current of 1C+0.2C to 3.8V.

[0050] Nail penetration: A high-temperature resistant steel needle (with a smooth surface and no rust, oxide layer, or oil stains) with a diameter taper of 45° to 60° was penetrated perpendicularly into the battery plate at a speed of (25±5) mm / s, preferably with the penetration position close to the geometric center of the puncture surface. The steel needle was then attached to the battery and observed for 1 hour.

[0051] The parameters and test results for each example and comparative example are shown in the table below. [Table 1]

number

[0052] As can be seen from the test results, when A is greater than 850, the battery fails the nail penetration test and thermal runaway occurs, but when A is less than 850 and greater than 3, the battery can pass the nail penetration test and thermal runaway does not occur, which demonstrates that the lithium-ion battery meeting the conditions of this application has a lower risk of runaway and higher safety.

[0053] In the description herein, references to terms such as "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" mean that the specific features, structures, materials, or characteristics described in combination with the embodiment or example are included in at least one embodiment or example of the present application. In the description herein, the exemplary expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, unless mutually inconsistent, a person skilled in the art may combine or combine different embodiments or examples and features of different embodiments or examples described herein.

[0054] Although the embodiments of the present application have been shown and described above, it should be understood that the above embodiments are illustrative and should not be construed as limiting the present application, and that those skilled in the art may make changes, modifications, substitutions and variations to the above embodiments within the scope of the present application.

Claims

1. A lithium ion battery including a metal case and an electrode assembly sealed within the case, The electrode body is a laminated electrode body including a plurality of positive electrode sheets and negative electrode sheets alternately stacked with separators sandwiched therebetween, or a wound electrode body including positive electrode sheets, separators, and negative electrode sheets stacked and wound, the positive electrode sheets including a positive electrode current collector and a positive electrode material layer carried on the positive electrode current collector, the positive electrode current collector being defined as an effective member, and the effective member satisfies the following conditions: [Equation 1] where L is the dimension of the effective member in the first direction, L is in m, W is the dimension of the effective member in the second direction, W is in m, and d ２ is the thickness of the effective member, and d ２ is the density of the effective material, and ρ is the unit of kg / m ３ and C ｐ is the specific heat capacity of the effective member, and C ｐ is in J / (Kg ° C), the first direction is parallel to a direction in which a current is drawn out from the effective member, and the second direction intersects with the first direction; The lithium ion battery is a rectangular battery, and the length of the case is 500 mm to 2500 mm.

2. 2. The lithium ion battery according to claim 1, wherein the effective member satisfies the following conditions: [Equation 2]

3. 3. The lithium ion battery according to claim 1, wherein a positive electrode tab is drawn out from one side of the positive electrode current collector, and the first direction is parallel to the drawing direction of the positive electrode tab.

4. 4. The lithium ion battery according to claim 1, wherein the second direction is perpendicular to the first direction.

5. The positive electrode current collector is The thickness d of the positive electrode current collector ２ The condition that the value range is between 6 μm and 15 μm; The range of the density ρ of the positive electrode current collector is 2000 kg m －３ ~3000 kg m －３ The condition that it is between The specific heat capacity C of the positive electrode current collector ｐ The value range is 800 J kg －１ ・K －１ ~900 J / kg －１ ・K －１ The condition that it is between a range of a value of a ratio L / w of a dimension L in a first direction of the positive electrode current collector to a dimension W in a second direction of the positive electrode current collector is between 2 and 30. The lithium ion battery according to any one of claims 1 to 4,

6. 6. The lithium ion battery according to claim 1, wherein the material of the positive electrode current collector contains aluminum.

7. The electrode body is the positive electrode material layer contains a lithium iron phosphate material; and the negative electrode sheet contains a negative electrode active material containing at least one of graphite, soft carbon, hard carbon, carbon fiber, mesocarbon microbeads, a silicon-based material, a tin-based material, and lithium titanate. The lithium ion battery according to any one of claims 1 to 6, characterized in that at least one of the following conditions is satisfied:

8. The lithium ion battery according to any one of claims 1 to 7, characterized in that there are a plurality of electrode bodies sealed in the case, and the plurality of electrode bodies are divided into a plurality of electrode body groups connected in series.

9. The lithium ion battery according to any one of claims 1 to 8, characterized in that a sealing film is further installed between the case and the electrode body, and the electrode body is sealed within the sealing film.

10. A battery pack comprising at least one lithium ion battery according to any one of claims 1 to 9.

11. An electric vehicle comprising the battery pack according to claim 10.

12. An energy storage device comprising the battery pack of claim 10.

Images