Electrodes containing blended active materials

Abstract

To provide electrodes comprising active material blends formulated to achieve specific performance properties, such as high energy density, high solids, high rate performance, high power density, and / or low temperature performance.SOLUTION: Electrodes for lithium-ion batteries are provided comprising: a first lithium metal phosphate material comprising a first plurality of active material particles; and a second lithium metal phosphate material comprising a second plurality of active material particles, where both the first lithium metal phosphate material and the second lithium metal phosphate material are LiMPO4, where M is one or more of iron (Fe) and manganese (Mn), and where the first lithium metal phosphate material is blended with the second lithium metal phosphate material at a weight ratio greater than 1:1.SELECTED DRAWING: Figure 1A

Description

[Technical Field]

[0001] The present disclosure relates generally to cathode active materials, and more particularly to formulating cathode active materials for lithium-ion batteries. Summary of the Invention [Problem to be solved by the invention]

[0002] Active material blends, cathodes including the blended active materials, lithium-ion batteries having cathodes including the blended active materials, and electric vehicles including lithium-ion batteries having cathodes including the blended active materials are provided. Specifically, described embodiments include blending a first lithium phosphate material including a first plurality of particles and a second lithium metal phosphate material including a second plurality of particles in a weight ratio greater than 1:1. In some embodiments, the second plurality of particles can include secondary particles including aggregates of primary particles. In some embodiments, the second lithium metal phosphate material includes both secondary particles and primary particles. In some embodiments, both the first lithium metal phosphate material and the second lithium metal phosphate material include only primary particles.

[0003] Both the first and second lithium metal phosphate materials have the formula LiMPO4, where M is one or more of manganese (Mn) or iron (Fe). In some embodiments, the first and second lithium metal materials can have different chemical formulas. In some embodiments, the chemical formulas of the first and second lithium metal phosphate materials can be the same.

[0004] The active material formulations described herein are formulated to achieve specific performance characteristics, such as high energy density, high solids, high rate capability, high power density, and / or low temperature performance. These active material formulations can be used in lithium ion batteries having cylindrical, prismatic, and / or pouch configurations. In some embodiments, the formulated active materials described herein can be used to fabricate cathodes for rechargeable lithium ion batteries for use in electric vehicles.

[0005] In some embodiments, an electrode for a lithium-ion battery is provided that includes a first lithium metal phosphate material including a first plurality of active material particles and a second lithium metal phosphate material including a second plurality of active material particles, wherein both the first lithium metal phosphate material and the second lithium metal phosphate material are LiMPO4, where M is one or more of iron (Fe) or manganese (Mn), and the first lithium metal phosphate material is blended with the second lithium metal phosphate material in a weight ratio of greater than 1:1.

[0006] In some embodiments of the electrode, the D50 of the active material particles of the first plurality of active material particles of the first lithium metal phosphate material is less than the D50 of the active material particles of the second plurality of active material particles of the second lithium metal phosphate material.

[0007] In some embodiments of the electrode, the first plurality of active material particles comprises primary active material particles.

[0008] In some embodiments of the electrode, the second plurality of active material particles includes primary active material particles and secondary active material particles.

[0009] In some embodiments of the electrode, the secondary active material particles of the second lithium metal phosphate material comprise agglomerates of primary active material particles.

[0010] In some embodiments of the electrode, the first and second lithium metal phosphate materials are the same, LiMPO4.

[0011] In some embodiments of the electrode, the D50 of the primary active material particles of the first plurality of active material particles of the first lithium metal phosphate material is between 150 nanometers and 2 micrometers.

[0012] In some embodiments of the electrode, the secondary active material particles of the second plurality of active material particles of the second lithium metal phosphate material have a D50 of 1 to 20 micrometers.

[0013] In some embodiments of the electrode, the combination of the first lithium metal phosphate material and the second lithium metal phosphate material comprises 0.5 to 3 wt. % carbon.

[0014] In some embodiments of the electrode, the electrode has a resistivity of 600 ohm-cm or less.

[0015] In some embodiments of the electrode, the combination of the first lithium metal phosphate material and the second lithium metal phosphate material has a tap density of 0.8 g / cc or greater.

[0016] In some embodiments of the electrode, the first lithium metal phosphate material is blended with the second lithium metal phosphate material in a weight ratio greater than 3:2.

[0017] In some embodiments of the electrode, the first lithium metal phosphate material is blended with the second lithium metal phosphate material in a weight ratio of greater than 3:1.

[0018] In some embodiments of the electrode, the electrode has an electrode press density of 1.8 to 2.8 g / cc.

[0019] In some embodiments of the electrode, the D50 of the primary active material particles of the first plurality of active material particles of the first lithium metal phosphate material is 150 nanometers or greater, and the surface area of the primary active material particles of the first plurality of active material particles of the first lithium metal phosphate material is 15 m or greater. 2 / g or less.

[0020] In some embodiments of the electrode, the D50 of at least one of the primary active material particles of the first plurality of active material particles of the first lithium metal phosphate material or the primary active material particles of the second plurality of active material particles of the second lithium metal phosphate material is 350 nanometers or less.

[0021] In some embodiments of the electrode, the D50 of the primary active material particles of the first plurality of active material particles of the first lithium metal phosphate material is less than or equal to 350 nanometers.

[0022] In some embodiments, a rechargeable lithium-ion battery is provided, the battery comprising an electrode including a first lithium metal phosphate material including a first plurality of active material particles and a second lithium metal phosphate material including a second plurality of active material particles, both the first lithium metal phosphate material and the second lithium metal phosphate material being LiMPO4, where M is one or more of iron (Fe) or manganese (Mn), and the first lithium metal phosphate material is blended with the second lithium metal phosphate material in a weight ratio of greater than 1:1.

[0023] In some embodiments, an electric vehicle system is provided, the electric vehicle system comprising a rechargeable lithium ion battery with electrodes comprising a first lithium metal phosphate material comprising a first plurality of active material particles and a second lithium metal phosphate material comprising a second plurality of active material particles, both the first lithium metal phosphate material and the second lithium metal phosphate material being LiMPO4, where M is one or more of iron (Fe) or manganese (Mn), and the first lithium metal phosphate material is blended with the second lithium metal phosphate material in a weight ratio of greater than 1:1.

[0024] The above-disclosed embodiments are examples, and the scope of the present disclosure is not limited thereto. Particular embodiments may include all, some, or none of the components, elements, features, functions, operations, or steps of the above-disclosed embodiments. Dependencies or backward references in the appended claims are selected for formality reasons only. However, just as any combination of claims and their features may be claimed regardless of the dependencies disclosed and selected in the appended claims, any subject matter resulting from an intentional backward reference (especially a multiple dependency) to any preceding claim may likewise be claimed. Subject matter that may be claimed includes not only combinations of features set forth in the appended claims, but also any other combinations of features in the claims, and each feature recited in a claim may be combined with any other feature or combination of features in the claim. Furthermore, any of the embodiments and features described or depicted herein may be claimed in a separate claim and / or in any combination with any embodiment or feature described or depicted herein or with any of the features of the appended claims. [Brief explanation of the drawings]

[0025] [Figure 1A] FIG. 1A shows a scanning electron microscope image of an active material including only primary particles, according to some embodiments. [Figure 1B] FIG. 1B shows a scanning electron microscope image of an active material comprising secondary spherical particles made from primary particles, according to some embodiments. [Figure 1C] FIG. 1C shows a scanning electron microscope image of a blended active material including a first active material including only primary particles and a second active material including secondary spherical particles, according to some embodiments. [Figure 2A] FIG. 2A shows a coating layer that includes an active material that includes only primary particles, according to some embodiments. [Figure 2B]FIG. 2B shows a coating layer including an active material including secondary particles, according to some embodiments. [Figure 2C] FIG. 2C shows a coating layer including a blend of a first active material including only primary particles and a second active material including secondary particles, according to some embodiments. [Figure 3A] FIG. 3A shows a diagram of an electrode comprising small primary particles and large secondary particles, resulting in higher tap and / or electrode density, according to some embodiments. [Figure 3B] FIG. 3B shows a diagram of an electrode including secondary particles or larger primary particles relative to the particles of FIG. 3A, resulting in higher porosity, according to some embodiments. [Figure 4A] FIG. 4A is a graph showing the relationship between solids content in a slurry and surface area of the cathode active material for four different grades of lithium ion phosphate material, according to some embodiments. [Figure 4B] FIG. 4B is a graph showing the relationship between tap density and carbon content for four different grades of lithium ion phosphate material, according to some embodiments. [Figure 4C] FIG. 4C is a graph showing the relationship between electrical resistivity and carbon content for four different grades of lithium ion phosphate material, according to some embodiments. [Figure 5] FIG. 5 is a graph showing the room temperature electrochemical performance of four different lithium-ion batteries using coin half-cells with metallic lithium anodes, each containing a different active material or active material blend, according to some embodiments. [Figure 6] FIG. 6 is a graph showing discharge curves for four different lithium-ion batteries using full cells with graphite anodes at low temperature (−10° C.) and high C-rate (2C), each containing a different active material or blend of active materials, according to some embodiments. [Figure 7A]FIG. 7A is a graph showing various discharge rate performance for four different lithium-ion batteries using full cells with graphite anodes at low temperature (−10° C.) and low C-rate (0.1 C, 10 hour discharge), each containing a different active material or active material blend, according to some embodiments. [Figure 7B] FIG. 7B is a graph showing various discharge rate performance for four different lithium-ion batteries using full cells with graphite anodes at low temperature (−10° C.) and normal operating C-rate (0.33 C, 3 hour discharge), each containing a different active material or active material blend, according to some embodiments. [Figure 7C] FIG. 7C is a graph showing various discharge rate performance for four different lithium-ion batteries using full cells with graphite anodes at low temperature (−10° C.) and higher C-rates (1 C, 1 hour discharge), each containing a different active material or active material blend, according to some embodiments. [Figure 7D] FIG. 7D is a graph showing various discharge rate performance for four different lithium-ion batteries using full cells with graphite anodes at low temperature (−10° C.) and higher C-rates (2 C, 30 min discharge), each containing a different active material or active material blend, according to some embodiments. [Figure 8] FIG. 8 illustrates a flow chart for a typical battery cell manufacturing process, according to some embodiments. [Figure 9] FIG. 9 depicts an illustrative example of a cross-sectional view of a cylindrical battery cell, according to some embodiments. [Figure 10] FIG. 10 depicts an illustrative example of a cross-sectional view of a prismatic battery cell, according to some embodiments. [Figure 11] FIG. 11 depicts an illustrative example of a cross-sectional view of a pouch battery cell, according to some embodiments. [Figure 12] FIG. 12 illustrates cylindrical battery cells being inserted into a frame to form a battery module and pack, according to some embodiments. [Figure 13] FIG. 13 illustrates prismatic battery cells being inserted into a frame to form a battery module and pack, according to some embodiments. [Figure 14] FIG. 14 illustrates pouch battery cells being inserted into a frame to form a battery module and pack, according to some embodiments. [Figure 15] FIG. 15 illustrates an example of a cross-sectional view of an electric vehicle including at least one battery pack, according to some embodiments. DETAILED DESCRIPTION OF THE INVENTION

[0026] Provided herein are active material blends, cathodes including the active material blends, lithium ion batteries having cathodes including the blended active materials, electric vehicles including lithium ion batteries having cathodes including the blended active materials, and methods for blending cathode active materials.

[0027] Most electric vehicles rely on rechargeable lithium-ion batteries as their primary power source. The cathode of a rechargeable lithium-ion battery, and more specifically, the electrochemistry of a rechargeable lithium-ion battery, can affect the battery's performance (e.g., energy density, cycle life). For example, one commonly used cathode material for rechargeable lithium-ion batteries is lithium metal phosphate material (LiMPO4), where M can be iron (Fe) or manganese (Mn), or a mixture of both Fe and Mn.

[0028] Generally, different grades of lithium metal phosphate materials are used to achieve specific target battery characteristics. For example, for high power applications, lithium metal phosphate materials with smaller particles are generally utilized. For high energy density applications, lithium metal phosphate materials with larger particles are generally utilized. However, to achieve a battery with both suitable power output and suitable energy density, for example, electrodes can be fabricated using a blend of two or more lithium metal phosphate materials, as described herein.

[0029] It has been determined that the performance characteristics of lithium-ion batteries (and electric vehicles powered by such lithium-ion batteries) can be optimized by formulating cathode active materials according to specific ratios as described herein.

[0030] In some embodiments, the formulated active material can include a first lithium metal phosphate material comprising a first plurality of particles and a second lithium metal phosphate material comprising a second plurality of particles. In some embodiments, the first plurality of particles of the first lithium metal phosphate material has a D50 of 150 nanometers (nm) to 2 micrometers (μm). In some embodiments, the second plurality of particles of the second lithium metal phosphate material has a D50 of 1 to 20 μm. In some embodiments, the second plurality of particles can be an agglomerate of primary particles and formed by spray drying. In some embodiments, the D50 of the secondary particles is greater than the D50 of the primary particles. As used herein, "D50" refers to the median particle size, or particle size (diameter) at 50% of the cumulative distribution, measured by a particle size analyzer (PSA). Because primary particles tend to agglomerate together, especially in nano-sized powders, PSA measurements (e.g., D10, D50, D90, D100) do not necessarily represent the size of a single crystal particle. Furthermore, as used herein, "D10" refers to the particle size (diameter) of 10% of the cumulative distribution, and "D90" refers to the particle size (diameter) of 90% of the cumulative distribution.

[0031] Both the first lithium metal phosphate material and the second metal phosphate material have the chemical formula LiMPO4, where M is one or more of iron (Fe) or manganese (Mn). In some embodiments, both the first and second lithium metal phosphate materials can have the same chemical formula. In some embodiments, the first and second lithium metal phosphate materials can have different chemical formulas.

[0032] To form a formulated active material for use in a cathode, the first lithium metal phosphate material is blended with the second lithium metal phosphate material in a weight ratio greater than 1:1 (i.e., the total weight of the first lithium metal phosphate material including the first plurality of particles is greater than the total weight of the second lithium metal phosphate material including the second plurality of particles). The exact blending ratio can be determined based on the target performance characteristics, as described in more detail below.

[0033] 1A shows a scanning electron microscope image of an active material including only primary particles according to some embodiments. The material depicted in FIG. 1A may be a "first lithium metal phosphate material" and / or a "second lithium metal phosphate material" as described herein. The material in FIG. 1A may also be a LiMPO4 material, where M is one or more of iron (Fe) or manganese (Mn).

[0034] In some embodiments, the primary particles are approximately spherical in shape. As indicated by the scale provided in the figure, the primary particles of the material depicted in FIG. 1A are measured in nanometers (i.e., significantly smaller than 1 micrometer, as depicted). However, the size of the particles depicted in FIG. 1A is merely one example of a suitable particle size. Different embodiments of the formulated active materials described herein may include lithium metal phosphate materials comprising primary particles of different sizes than those depicted in the figures. For example, the D50 of the primary particles of the lithium metal phosphate material for the formulated active materials described herein may be 300 nanometers (nm) to 2 micrometers (μm), or 150 nm to 1 μm. In some embodiments, the D50 of the primary particles of the lithium metal phosphate material may be 2 μm, 1 μm, 750 nm, 500 nm, or 250 nm or less. In some embodiments, the D50 of the primary particles of the lithium metal phosphate material can be 150 nm, 250 nm, 500 nm, 750 nm, or 1 μm or greater. "D50" refers to the median particle size measured by a particle size analyzer (PSA); therefore, the D10 can be equal to or less than the D50. In some embodiments, the lithium metal phosphate material includes only primary particles and does not include secondary particles. Smaller primary particles have shorter paths for lithium ion diffusion during charge and discharge processes, which means that smaller primary particles are typically better for high C-rate charge / discharge processes. Also, lithium diffusion is hindered at low temperature operation. Therefore, smaller primary particles have a higher opportunity to absorb / desorb more lithium during low temperature operation.

[0035] In some embodiments, the primary particles of the lithium metal phosphate material have a particle size (D10-D90 inclusive) of 20 nanometers (nm) to 100 micrometers (μm). In some embodiments, the primary particles of the lithium metal phosphate material have a particle size (D10-D90 inclusive) of 100 μm, 50 μm, 1 μm, 750 nm, 500 nm, 250 nm, or 100 nm or less. In some embodiments, the primary particles of the lithium metal phosphate material have a particle size (D10-D90 inclusive) of 20 nm, 100 nm, 250 nm, 500 nm, 750, 1 μm, or 50 μm or more.

[0036] In some embodiments, the material of FIG. 1A may not be optimal for achieving good tab and packing density because it has a relatively large amount of void space between relatively small particles of similar size. Having a larger particle size distribution helps achieve better tab and packing density. In some embodiments, this material may be less optimal for low temperature performance, especially if the primary particle size is too large.

[0037] FIG. 1B shows a scanning electron microscope image of an active material comprising secondary spherical particles. Notably, the secondary particles shown in the figure comprise smaller primary particles. This material depicted in FIG. 1B may be a "second lithium metal phosphate material," as described herein. The material of FIG. 1B may also be a LiMPO4 material, where M is one or more of iron (Fe) or manganese (Mn).

[0038] The material depicted in FIG. 1B is a secondary spherical particle 102 having a primary particle 104 embedded therein. The primary particles are generally single crystals, while the secondary particles are aggregates of primary (single-crystal) particles intentionally formed using spray-drying techniques. In the embodiment depicted in FIG. 1B, the secondary particles are generally larger than the primary particles in both FIG. 1A and FIG. 1B. However, this is not always the case. Furthermore, the primary particles in FIG. 1B are not necessarily identical to those in FIG. 1A (e.g., based on chemical formula, crystal structure, etc.). Primary particles can be produced to significantly larger sizes (i.e., up to on the order of 10-25 micrometers) using higher heat treatment temperatures and / or larger precursors. In some embodiments, secondary particles can be spray-dried as small as 1 micrometer.

[0039] The sizes of both the primary and secondary particles depicted in FIG. 1B are merely examples of suitable particle sizes. Different embodiments of the formulated active materials described herein may include lithium metal phosphate materials comprising primary or secondary particles with particle size distributions different from those depicted in the figures. For example, in some embodiments, the D50 of the secondary particles of the lithium metal phosphate materials for the formulated active materials described herein may be 1 to 100 or 1 to 50 micrometers (μm). In some embodiments, the D50 of the secondary particles of the lithium metal phosphate materials may be 100, 50, 40, 30, 20, 10, or 5 μm or less. In some embodiments, the D50 of the secondary particles of the secondary lithium metal phosphate materials may be 1, 5, 10, 20, 30, 40, or 50 μm or greater. Lithium metal phosphate materials comprising a wider range of secondary particle sizes can improve the press density of the materials, which in turn increases the energy density.

[0040] In some embodiments, secondary particles of lithium metal phosphate materials for formulated active materials as described herein can have a particle size (D10-D90) of 1 to 100 micrometers (μm). In some embodiments, secondary particles of lithium metal phosphate materials for formulated active materials as described herein can have a particle size (D10-D90) of 100, 75, 50, or 25 μm or less. In some embodiments, secondary particles of lithium metal phosphate materials for formulated active materials as described herein can have a particle size (D10-D90) of 1, 25, 50, or 75 μm or more.

[0041] The D50 of the primary particles shown in FIG. 1B can be 300 nanometers (nm) to 2 micrometers (μm), or 150 nm to 1 μm. In some embodiments, the D50 of the primary particles can be 2 μm, 1 μm, 750 nm, 500 nm, or 250 nm or less. In some embodiments, the D50 of the primary particles can be 150 nm, 250 nm, 500 nm, 750 nm, or 1 μm or more. In some embodiments, the primary particles have a particle size (D10 to D90) of 20 nanometers (nm) to 100 micrometers (μm). In some embodiments, the primary particles have a particle size (D10 to D90) of 100 μm, 50 μm, 1 μm, 750 nm, 500 nm, 250 nm, or 100 nm or less. In some embodiments, the primary particles of the lithium metal phosphate material have a particle size (D10-D90 inclusive) of 20 nm, 100 nm, 250 nm, 500 nm, 750, 1 μm, or 50 μm or greater.

[0042] In some embodiments, the D50 of the particles of the second lithium metal phosphate material is greater than the D50 of the first lithium metal phosphate material. In some embodiments, the D50 of the particles of the second lithium metal phosphate material is 1.1 to 350 times greater than the D50 of the particles of the first lithium metal phosphate material. In some embodiments, the D50 of the particles of the second lithium metal phosphate material is no greater than 350, 300, 250, 200, 150, 100, 75, 50, 25, 10, or 5 times greater than the D50 of the particles of the first lithium metal phosphate material. In some embodiments, the D50 of the particles of the second lithium metal phosphate material is 1.1, 5, 10, 25, 50, 75, 100, 150, 200, 250, or 300 times greater than the D50 of the particles of the first lithium metal phosphate material.

[0043] In some embodiments, the material of Figure 1B may be optimal in terms of rate capability and low temperature performance, particularly when the primary particles within the secondary particles are very small (less than 200 nm). If the secondary particle sizes are similar to each other, the material may be less optimal in terms of energy density due to the presence of void space when the prepared electrodes are pressed between similarly sized secondary particles. However, this may be optimized when a different secondary particle size distribution is present, similarly reducing the void space.

[0044] 1C shows a scanning electron microscope image of a blended active material including a first active material including only primary particles (e.g., as depicted in FIG. 1A) and a second active material including secondary particles (e.g., as depicted in FIG. 1B), according to some embodiments. As shown in the figure, the blended material includes a wider variety of particles and particle sizes than either the first lithium metal phosphate material or the second lithium metal phosphate material alone.

[0045] Below is a table showing exemplary differences in properties among the three materials. The "Large Secondary" column may represent a second lithium metal phosphate material (e.g., the material of FIG. 1B), the "Small Particle" column may represent a first lithium metal phosphate material (e.g., the material of FIG. 1A), and the "Blend" column may represent a blended active material including a blend of a first lithium metal phosphate material and a second lithium metal phosphate material (e.g., the material of FIG. 1C).

[0046] [Table 1]

[0047] The specific blend ratio of the first lithium metal phosphate material to the second lithium metal phosphate material can be selected based on the target characteristics of the active materials and / or the battery containing the electrodes fabricated using the blended active materials. In some embodiments, the weight ratio between the first lithium metal phosphate material and the second lithium metal phosphate material is greater than 1:1 (i.e., the total weight of the first lithium metal phosphate material is greater than the total weight of the second lithium metal phosphate material). In some embodiments, the weight ratio between the first lithium metal phosphate material and the second lithium metal phosphate material is from 1:1 to 9.5:1, 3:2 to 9:1, or 2:1 to 4:1. In some embodiments, the weight ratio between the first lithium metal phosphate material and the second lithium metal phosphate material is greater than 3:2, 2:1, 7:3, 3:1, 4:1, 9:1, or 9.5:1. In some embodiments, the weight ratio between the first lithium metal phosphate material and the second metal phosphate material is 9.5:1, 9:1, 4:1, 3:1, 7:3, 2:1, or 3:2 or less. Generally, for electric vehicle applications requiring high energy density, larger lithium metal phosphate primary particles with a D50 approaching 500 nm to 1 μm are most beneficial for achieving higher energy load targets. However, larger particles have reduced rate and low-temperature performance. Very small primary particles (i.e., less than 300 nm), either as primary particles or within secondary particles, are beneficial for improving rate and low-temperature performance.

[0048] FIG. 2A shows a Hegman gauge test of an active material including only primary particles, according to some embodiments. As shown, small primary particles can provide a clean, smooth coating without too many agglomerates to the right of the grindometer gauge (units: μm). FIG. 2B shows a Hegman gauge test of an active material including secondary particles, according to some embodiments. Larger agglomerate particles of this material can cause inconsistencies or defects in the coating layer; large agglomerates can cause "drag lines" or appear as "spots." However, FIG. 2C shows a Hegman gauge test of a blend of a first active material and a second active material, according to some embodiments. This blended material can form a material with acceptable physical properties (e.g., fewer inconsistencies or imperfections compared to that of FIG. 2B, where "drag lines" appear at the 30 μm scale bar and can be coated with an additional filtration step at a mass production scale).

[0049] 3A shows a diagram of an electrode including small primary particles and large secondary particles, resulting in higher tap and / or electrode density, according to some embodiments, and FIG. 3B shows a diagram of an electrode including secondary particles or larger primary particles compared to the particles of FIG. 3A, resulting in higher porosity, according to some embodiments. As shown in FIG. 3A, the smaller primary particles may be able to fill gaps formed by the larger secondary particles. Thus, an electrode including both smaller nanometer-sized particles (e.g., smaller primary particles) and slightly larger (sub)micrometer-sized particles will have a packing density greater than that of a material with a more uniform particle size (regardless of whether the material with a more uniform particle size includes primary particles and / or secondary particles).

[0050] Generally, an electrode containing a material with a narrower particle distribution (i.e., a more uniform particle size) will result in a lower tap / packing density. In contrast, the packing density of a blended material having a first lithium metal phosphate material with a first plurality of particles and a second lithium metal phosphate material with a second plurality of particles can be higher because the particle size variation between the first and second materials is greater than the particle size variation of a single lithium metal phosphate material. In some embodiments, the packing density of a blended material as described herein can be 1.5 to 3 g / cc. In some embodiments, the packing density of a blended material as described herein can be 3, 2.9, 2.8, 2.7, 2.6, 2.5, 2.4, 2.3, 2.2, 2.1, 2, 1.9, 1.8, 1.7, or 1.6 g / cc or less. In some embodiments, the packing density of the compounded materials as described herein can be 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, or 3 g / cc or greater. Higher packing densities can increase the volumetric energy density of a given battery cell, module, and pack.

[0051] Method of Combining a First Lithium Metal Phosphate Material and a Second Lithium Metal Phosphate Material In some embodiments, the blended active material described above can be formed by blending a first lithium metal phosphate material and a second lithium metal phosphate material in a predetermined weight ratio. For example, the first lithium metal phosphate material can be blended with the second lithium metal phosphate material in a blending weight ratio of 4:1. To properly blend the two materials together to achieve the blended material, the first and second lithium metal phosphate materials can be blended together by simple blending, dry milling, or wet milling. Simple blending involves premixing the two materials together during the slurry preparation process. Dry milling includes a ball milling process without a solvent. Wet milling is a ball milling process using an aqueous solution such as HO, a solvent such as isopropyl alcohol, ethanol, acetone, any other organic solvent, or any mixture thereof.

[0052] Other blending methods can be used to combine the first lithium metal phosphate material with the second metal phosphate material. For example, suitable methods can include monoblending, ball milling, or mechanochemical mixing. [Example]

[0053] Example 1: Slurry solids content and surface area 4A is a graph showing the relationship between solids content and surface area for four different grades of lithium ion phosphate material, according to some embodiments. Samples with higher surface area (e.g., LFP4 in FIG. 4A) generally have higher carbon content and / or very small particle size. Generally, having a higher carbon content (and higher surface area) can increase the total surface area of the LFP / C, even if the LFP particles are the same size. Higher surface area LFP / C requires more solvent, which results in lower solids content because the wetting process requires more solvent (e.g., n-methyl-2-pyrrolidone or NMP) to reduce the viscosity of the slurry so that it can be "coatable" in a slot die coater. For example, 9 m 2 / g to 15m 2 / g, which is 6m in surface area per gram of active material. 2 For 10 grams of LFP / C, the increase in active surface area is 60 m 2 , 1kg, 6,000m 2 , and 1 ton is 6,000,000 m 2 This will result in an increase in

[0054] For a blended material comprising a first lithium metal phosphate material comprising a first plurality of particles and a second lithium metal phosphate material comprising a second plurality of particles, the surface area of the particles may be between 3 and 30 or between 5 and 15 m 2 / g. As mentioned above, the smaller particles + Although it is good to aid diffusion (better rate, better low temperature performance), it is better to have a material with a reduced surface area for processability and cost (i.e., more NMP is needed). For example, the maximum target surface area for formulated LFPs is 18 m due to processability concerns. 2 In some embodiments, the particle surface area of the combined material comprising a first lithium metal phosphate material comprising a first plurality of particles and a second lithium metal phosphate material comprising a second plurality of particles is 30, 25, 20, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, or 5 m / g. 2 In some embodiments, the surface area of the particles of a combined material comprising a first lithium metal phosphate material comprising a first plurality of particles and a second lithium metal phosphate material comprising a second plurality of particles can be 3, 5, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, or 25 m 2 / g or more. Materials containing particles with higher surface areas require more solvent. Specifically, the likelihood of dissolution of the active material by the electrolyte in batteries with particles with higher surface areas also increases if the surface MO octahedra are less coordinated (e.g., MO5, MO4, etc.) compared to the bulk MO6 octahedra.

[0055] Example 2: Tap density and carbon content FIG. 4B is a graph showing the relationship between tap density and carbon content for four different grades of lithium-ion phosphate material, according to some embodiments. Note that the four different grades of lithium-ion phosphate material differ from those shown in FIG. 4A. Generally, as shown in the graph, lithium-ion phosphate materials with higher carbon contents have lower tap densities. Furthermore, lithium-ion phosphate materials with higher carbon contents also generally have lower adhesion strength to aluminum current collectors when the electrode fill level and press density are high. Typically, the strength of a coating is determined by the surface quality of the active material coating. In a given electrode, the binder acts as an adhesive that bridges the particles with the conductive material and the current collector. Increasing the carbon content increases the surface area and reduces the coverage of the binder content at the interface. To prevent this, a C-coated foil (which contains a binder in addition to the carbon coating layer) must be used, which modifies the interface between the electrode and the foil, and is more expensive than regular Al foil.

[0056] For a combined material comprising a first lithium metal phosphate material having primary particles and a second lithium metal phosphate material having secondary particles, the carbon content can be 0.5-3 wt. % or 0.8-1.6 wt. % of the electrode material. In some embodiments, the carbon content can be 3, 2.5, 2, 1.5, or 1 wt. % or less of the electrode material. In some embodiments, the carbon content can be 0.5, 1, 1.5, 2, or 2.5 wt. % or more of the electrode material. As the carbon content of a lithium metal phosphate material increases, the total BET (Brunauer, Emmett, and Teller) surface area also increases, which is generally undesirable. A higher carbon content also generally reduces tap density, as explained above. Conversely, insufficient carbon content can cause low electrical conductivity and reduced electrochemical performance.

[0057] In some embodiments, a combined material including a first lithium metal phosphate material having primary particles and a second lithium metal phosphate material having secondary particles can have a tap density of 0.8 to 1.5 g / cc. In some embodiments, the tap density can be 1.5, 1.4, 1.3, 1.2, 1.1, or 1.0 g / cc or less. In some embodiments, the tap density can be 0.8, 0.9, 1.0, 1.1, 1.2, or 1.3 g / cc or more. Higher tap densities are associated with better packing of the electrodes.

[0058] Example 3: Resistivity and Carbon Content 4C is a graph showing the relationship between resistivity and carbon content for four different grades of lithium ion phosphate material, according to some embodiments. Note that the four different grades of lithium ion phosphate material in FIG. 4C are different from the materials shown in FIGS. 4A and 4B. As shown in the graph, lithium ion phosphate materials with higher carbon content generally have lower electrical resistivity.

[0059] In some embodiments, the formulated active material with the first lithium metal phosphate material can have a resistivity of 100 to 700 ohm-cm. In some embodiments, the formulated active material with the first lithium metal phosphate material can have a resistivity of 700, 600, 500, 400, 300, 200, or 100 ohm-cm or less. In some embodiments, the formulated active material with the first lithium metal phosphate material can have a resistivity of 10, 20, 30, 40, 50, 60, 70, 80, or 90 ohm-cm or more.

[0060] Example 4: Room temperature performance 5 is a graph showing the room temperature performance of four different lithium-ion half-cell batteries, each containing a different active material or blend of active materials, according to some embodiments. The characteristics of each battery tested are provided in the table below:

[0061] [Table 2]

[0062] Furthermore, Sample 1 contained only small, medium, and large sized primary particles, Sample 2 contained medium to large micrometer sized secondary particles with very small primary particles embedded inside, Sample 3 contained only small, medium, and large primary particles, and Sample 4 contained only a narrower band of primary particles (when compared to Sample 3).

[0063] As shown in the graph of Figure 5, there is no significant difference between Samples 1, 2, and 3. However, Sample 4 provides a slightly lower discharge capacity than Samples 1, 2, and 3. The test conditions were: Li + The tests are performed at room temperature at low rates, without too much deformation, providing enough time for most of the ions to enter and exit the cathode electrode.

[0064] Example 5: Discharge 6 is a graph showing discharge curves for four different lithium-ion batteries, each containing a different active material or active material blend, according to some embodiments. The batteries used the same electrode weight design (active material:conductive carbon:binder content), graphite anode, separator, and cathode materials, except for identical conditions, as described above. (Samples 1-4 in FIG. 6 are the same as Samples 1-4 in FIG. 5.)

[0065] All tests performed and depicted in Figure 6 were small pouch-filled cell tests at high rates and low temperatures. Because Li-ion diffusion kinetics is very slow at these conditions, the voltage plateau at 3.2 V vs. graphite (compared to Figure 5) is shown to be no longer a flat line. The cell data from Figure 5 is from a half-cell test configuration, so the Li / Li + It should be noted that there is a flat line at 3.4V for SiO 2 , which is equivalent to 3.2V for graphite.

[0066] Example 6: Discharge Rate FIG. 7A is a graph showing various discharge rate performance for four different lithium-ion batteries, each containing a different active material or active material blend, according to some embodiments. Specifically, the tests shown in FIG. 7A were conducted at −10° C. and 0.1° C. Sample 1 contained small, medium, and large primary particles. From a blending perspective, larger particles would not contribute to capacity under these test conditions. Sample 2 contains larger secondary particles but small primary particles that contribute to discharge capacity under these test conditions. Sample 3 is similar to Sample 1, but has much smaller particles, and the large particles are not too large. Sample 4, containing only medium to large particles, yields the lowest capacity under these test conditions. (Samples 1-4 in FIG. 7A are the same as Samples 1-4 in FIGS. 5 and 6.)

[0067] Example 7: Discharge Rate FIG. 7B is a graph showing various discharge rate performance for four different lithium-ion batteries, each containing a different active material or active material blend, according to some embodiments. Specifically, the tests shown in FIG. 7B were conducted at −10° C. and 0.33° C. Similar trends are seen here as in FIG. 7A, but because the tests were conducted at a 3-hour discharge condition (0.33° C.), the overall capacity is smaller and the nominal voltage is lower. (Samples 1-4 in FIG. 7B are the same as Samples 1-4 in FIGS. 5, 6, and 7A.)

[0068] Example 8: Discharge Rate FIG. 7C is a graph showing various discharge rate performance for four different lithium-ion batteries, each containing a different active material or active material blend, according to some embodiments. Specifically, the tests shown in FIG. 7C were conducted at −10° C. and 1° C. As the C-rate increases, the degradation in nominal voltage and capacity becomes more pronounced. (Samples 1-4 in FIG. 7C are the same as Samples 1-4 in FIGS. 5, 6, 7A, and 7B.)

[0069] Example 9: Discharge Rate FIG. 7D is a graph showing various discharge rate performance for four different lithium-ion batteries, each containing a different active material or active material blend, according to some embodiments. Specifically, the tests shown in FIG. 7D were conducted at −10° C. and 2° C. As the C-rate increases, the drop in nominal voltage and capacity becomes more pronounced. In the case of Sample 4, only 20 mAh / g (out of a theoretical capacity of 170 mAh / g) is recovered. (Samples 1-4 in FIG. 7D are the same as Samples 1-4 in FIGS. 5, 6, 7A, 7B, and 7C.)

[0070] Battery cell, battery module, battery pack, and electric vehicle system The blended active materials described above, particularly blended active materials comprising a first lithium metal phosphate material comprising primary particles and a second lithium metal phosphate material comprising secondary particles, can be used in the manufacture of electrodes. More specifically, the blended active materials described herein can be used in the manufacture of cathodes that can be used to form battery cells, battery modules, and / or battery packs. Battery cells, battery modules, and / or battery packs including cathodes fabricated using the blended active materials described herein can then be used as power sources for electric vehicles. These embodiments are described in detail below.

[0071] Reference will now be made to implementations and embodiments of various aspects and variations of battery cells, battery modules, and battery packs, as well as methods of making such battery cells, battery modules, and battery packs. While several exemplary variations of battery cells, modules, packs, and methods of making the same are described herein, other variations of battery cells, modules, packs, and methods may include aspects of the battery cells, modules, packs, and methods described herein combined in any suitable manner, having all or some combination of the described aspects. Additionally, any or all of the components, systems, methods, apparatus, devices, compositions, etc. described herein may be implemented in battery cells, battery modules, battery packs, and methods of making these battery cells, battery modules, and battery packs.

[0072] FIG. 8 illustrates a flowchart of a typical battery cell manufacturing process 1000. These steps are not exhaustive, and other battery cell manufacturing processes may include additional steps, or only a subset of these steps. In step 1001, an electrode precursor (e.g., binder, active material, conductive carbon additive) may be prepared. In some embodiments, this step may include mixing the electrode material (e.g., active material, more specifically, a formulated active material described herein) with additional components (e.g., binder, solvent, conductive additive, etc.) to form an electrode slurry. In some embodiments, this step may include synthesizing the electrode material itself.

[0073] In step 1002, an electrode may be formed. In some embodiments, this step may include coating an electrode slurry (i.e., an electrode slurry including a formulated active material according to embodiments described herein) onto a current collector. After coating, the coated current collector may be dried to evaporate any solvent. In some embodiments, this step may include calendering the coated current collector. Calendering may adjust the physical properties of the electrode (e.g., bonding, conductivity, density, porosity, etc.). In some embodiments, the electrode may then be sized via a slitting and / or notching machine to cut the electrode to the appropriate size and / or shape.

[0074] In step 1003, the battery cell can be assembled. After the electrodes, separator, and / or electrolyte are prepared, the battery cell can be assembled / prepared. In this step, a separator and / or electrolyte layer can be laminated between the anode layer and the cathode layer to form the internal structure of the battery cell. These layers can be laminated by a winding method such as round winding or square / flat winding, a lamination method, or a Z-fold method. The assembled cell structure can then be inserted into a cell housing, which can then be partially or completely sealed. Additionally, the assembled structure can be connected to terminals and / or cell tabs (via a welding process). In the case of a battery cell utilizing a liquid electrolyte, the housed cell with the electrode structure therein can also be filled with electrolyte and then sealed.

[0075] Battery cells can have a variety of form factors, shapes, or sizes. For example, battery cells (and their housings / casings) can have cylindrical, rectangular, square, cubic, flat, or prismatic form factors, among others. There are four main types of battery cells: (1) button or coin cells, (2) cylindrical cells, (3) prismatic cells, and (4) pouch cells. Battery cells can be assembled, for example, by inserting wound and / or stacked electrode rolls (e.g., jelly rolls) into a battery cell casing or housing. In some embodiments, the wound or stacked electrode rolls can include an electrolyte material. In some embodiments, the electrolyte material can be inserted into a battery casing or housing separate from the electrode rolls. In some embodiments, the electrolyte material includes, but is not limited to, an ionically conductive fluid or other material (e.g., a layer) that can enable charge flow (i.e., ion transport) between the cathode and anode. In some embodiments, the electrolyte material can include a non-aqueous polar solvent (e.g., a carbonate such as ethylene carbonate, propylene carbonate, diethyl carbonate, ethyl methyl carbonate, dimethyl carbonate, or a mixture of any two or more thereof). The electrolyte can also include other additives, such as, but not limited to, vinylidene carbonate, fluoroethylene carbonate, ethyl propionate, methyl propionate, methyl acetate, ethyl acetate, or a mixture of any two or more thereof. The lithium salt of the electrolyte can be any of those used in lithium battery construction, including, but not limited to, lithium perchlorate, lithium hexafluorophosphate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluorosulfonyl)imide, or a mixture of any two or more thereof. Additionally, the salt can be present in the electrolyte at greater than 0 M to about 0.5 M.

[0076] In some embodiments, the solid electrolyte membrane can include at least one layer of a solid electrolyte. The solid electrolyte material of the solid electrolyte layer can include an inorganic solid electrolyte material (e.g., oxide, sulfide, phosphide, ceramic), a solid polymer electrolyte material, a hybrid solid electrolyte, or a combination thereof. In some embodiments, the solid electrolyte layer can include a polyanionic or oxide-based electrolyte material (e.g., Lithium Superionic Conductor (LISICON), Sodium Superionic Conductor (NASICON), perovskites having the formula ABO (A=Li, Ca, Sr, La, and B=Al, Ti), garnets having the formula A3B2(XO4) (A=Ca, Sr, Ba, and X=Nb, Ta), lithium phosphorus oxy-nitrides (LixPOyNz). In some embodiments, the solid electrolyte layer can include glassy, ceramic, and / or crystalline sulfide-based electrolytes (e.g., Li3PS4, Li7P3S 11 , Li2S-P2S5, Li2S-B2S3, SnS-P2S5, Li2S-SiS2, Li2S-P2S5, Li2S-GeS2, Li10GeP2S12) and / or sulfide-based lithium argyrodites having the formula Li6PS5X (X = Cl, Br), such as Li6PS5Cl. Additionally, the solid electrolyte layer can include polymer electrolyte materials (e.g., hybrid or pseudo-solid electrolytes) such as polyacrylonitrile (PAN), polyethylene oxide (PEO), polymethyl-methacrylate (PMMA), and polyvinylidene fluoride (PVDF), among others.

[0077] In some embodiments, the anode active material is graphitic carbon (e.g., sp 2The anode material may include a current collector material such as a lithium ion battery (e.g., a lithium ion battery ...

[0078] In addition to the cathode active material (or for the anode active material), the electrode can include a conductive additive, typically a conductive carbon material, which can include graphite, carbon black, carbon nanotubes, Super P carbon black material, Ketjen black, acetylene black, SWCNTs, MWCNTs, carbon nanofibers, graphene, and combinations thereof. In addition to the cathode active material (or for the anode active material), the electrode can include a binder material to improve adhesion of the cathode (or anode) active material to the current collector foil. In some embodiments, the binder can include a polymeric material such as polyvinylidene fluoride ("PVDF"), polyvinylpyrrolidone ("PVP"), styrene-butadiene or styrene-butadiene rubber ("SBR"), polytetrafluoroethylene ("PTFE"), or the like. In various embodiments, the electrode material (e.g., active material, more specifically, the formulated active material described herein) with additional components (e.g., binder, solvent, conductive additive, etc.) can be mixed with a solvent to form an electrode slurry.

[0079] The cathode active material (or even the anode active material) can include a carbon coating. Generally, lithium metal phosphate includes a surface carbon coating to improve the conductivity of the active material. The carbon coating process can be carried out during or after the formation of the lithium metal phosphate; for example, pyrolysis of organic materials on the lithium metal phosphate particles at high temperatures can produce an active material with a carbon coating, and in some cases, a secondary conductive phase in the active material can be formed.

[0080] The cathode active material can include a carbon coating, such as 0.5-3% or 0.8-1.6% by weight of the active material. For example, 1% by weight of carbon coating material on 99% by weight of lithium metal phosphate active material. This active material can then be mixed with a carbon conductive additive (e.g., 3% by weight of conductive carbon additive to 97% by weight of active material) in an electrode slurry used to prepare the electrode.

[0081] 9 depicts an illustrative example of a cross-sectional view of a cylindrical battery cell 100. The cylindrical battery cell can include layers (e.g., sheet-like layers) of an anode layer 10, a separator and / or electrolyte layer 20, and a cathode layer 30.

[0082] The battery cell can include at least one anode layer, which can be disposed within a cavity of the housing / casing. The battery cell can also include at least one cathode layer. The at least one cathode layer can also be disposed within the housing / casing. In some embodiments, when the battery cell is discharging (i.e., providing current), the at least one anode layer releases ions (e.g., lithium ions) to the at least one cathode layer, generating a flow of electrons from one side to the other. Conversely, in some embodiments, when the battery cell is charging, the at least one cathode layer can release ions and the at least one anode layer can accept these ions.

[0083] These layers (cathode, anode, separator / electrolyte layer) may be sandwiched, rolled up, and / or packed into a cylindrically shaped casing 40 (e.g., a metal can). The casing / housing may be rigid, e.g., made from metal or hard plastic. In some embodiments, a separator layer (and / or electrolyte layer) 20 may be disposed between the anode layer 10 and the cathode layer 30 to separate them. In some embodiments, the layers within a battery cell may alternate, with the separator layer (and / or electrolyte layer) separating the anode layer from the cathode layer. In other words, the layers of the battery electrodes may be (in order): separator layer, anode / cathode layer, separator layer, opposite another anode / cathode layer, etc. The separator layer (and / or electrolyte layer) 20 may facilitate ion (e.g., lithium ion) transport within the cell while preventing contact between the anode and cathode layers. The battery cell may also include at least one terminal 50. The at least one terminal may be an electrical contact used to connect a load or charger to the battery cell. For example, the terminal may be made of an electrically conductive material to carry electrical current from the battery cell to an electrical load, such as a component or system of an electric vehicle, as discussed further herein.

[0084] FIG. 10 depicts an illustrative example of a cross-sectional view of a prismatic battery cell 200. The prismatic battery cell can include layers (e.g., sheet-like layers) of an anode layer 10, a separator and / or electrolyte layer 20, and a cathode layer 30. Similar to cylindrical battery cells, the layers of a prismatic battery cell can be sandwiched, rolled, and / or pressed to fit into a cubic or rectangular cuboid (e.g., hyper-rectangular) shaped casing / housing 40. In some embodiments, the layers can be assembled by layer lamination rather than jelly-rolling. In some embodiments, the casing or housing can be rigid, such as made from metal and / or hard plastic. In some embodiments, the prismatic battery cell 200 can include two or more terminals 50. In some embodiments, one of these terminals can be a positive terminal and the other can be a negative terminal. These terminals can be used to connect a load or a charger to the battery cell.

[0085] FIG. 11 depicts an illustrative example of a cross-sectional view of a pouch battery cell 300. A pouch battery cell does not have a rigid enclosure and instead uses a flexible material for the casing / housing 40. This flexible material can be, for example, a sealed flexible foil. The pouch battery cell can include layers (e.g., sheet-like layers) of an anode layer 10, a separator and / or electrolyte layer 20, and a cathode layer 30. In some embodiments, these layers are stacked within the casing / housing. In some embodiments, the pouch battery cell 200 can include two or more terminals 50. In some embodiments, one of these terminals can be a positive terminal and the other a negative terminal. These terminals can be used to connect a load or a charger to the battery cell.

[0086] The battery cell casing / housing can include one or more materials having various electrical or thermal conductivities, or a combination thereof. Electrically and thermally conductive materials for the battery cell casing / housing can include metallic materials such as aluminum, copper, silicon, tin, magnesium, manganese, or aluminum alloys with zinc (e.g., aluminum 1000, 4000, or 5000 series), iron, iron-carbon alloys (e.g., steel), silver, nickel, copper, and copper alloys, among others. In some embodiments, the electrically and thermally conductive materials for the battery cell housing can include ceramic materials (e.g., silicon nitride, silicon carbide, titanium carbide, zirconium dioxide, beryllium oxide, etc.) and / or thermoplastic materials (e.g., polyethylene, polypropylene, polystyrene, polyvinyl chloride, or nylon), among others.

[0087] In step 1004, the battery cells can be completed. In some embodiments, this step includes a formation process in which a first charge and discharge process for the battery cells is performed. In some embodiments, this initial charge and discharge can form a solid electrolyte interface between the electrolyte and the electrodes. In some embodiments, this step can cause some of the cells to produce gases that can be removed from the battery cells in a degassing process. In some embodiments, this step includes aging the battery cells. Aging can include monitoring cell characteristics and performance over a period of time. In some embodiments, this step can also include testing the cells in an end-of-line (EOL) test rig. EOL testing can include discharging the battery cells to their shipping state of charge, pulse testing, testing for internal resistance measurements, testing for OCV, testing for leakage, and / or, optionally, optically inspecting the battery cells for defects.

[0088] Multiple battery cells (100, 200, and / or 300) can be assembled or packaged together within the same housing, frame, or casing to form a battery module and / or pack. The battery cells of a battery module can be electrically connected to generate a certain amount of electrical energy. These multiple battery cells can be coupled to the outside of the housing, frame, or casing through a uniform boundary. The battery cells of a battery module can be parallel, series, or series-parallel combinations of battery cells. The housing, frame, or casing can protect the battery cells from various hazards (e.g., external elements, heat, vibration, etc.). FIG. 12 illustrates a cylindrical battery cell 100 being inserted into a frame to form a battery module 110. FIG. 13 illustrates a prismatic battery cell 200 being inserted into a frame to form a battery module 110. FIG. 14 illustrates a pouch battery cell 300 being inserted into a frame to form a battery module 110. In some embodiments, a battery pack may not include a module. For example, the battery pack may have a "module-free" or cell-to-pack configuration, where the battery cells are placed directly into the battery pack without assembly into a module.

[0089] As shown in FIGS. 12-14 , multiple battery modules 110 can be disposed within another housing, frame, or casing to form a battery pack 120. In some embodiments, multiple battery cells can be assembled, filled, and disposed within a housing, frame, or casing to form a battery pack (not shown). In such embodiments, the battery pack may not include battery modules (e.g., module-free). For example, the battery pack may have a cell-to-pack configuration in which battery cells can be placed directly into the battery pack without assembling them into battery modules. In some embodiments, the battery cells of the battery pack can be electrically connected to generate an amount of electrical energy that is provided to another system (e.g., an electric vehicle).

[0090] The battery modules of a battery pack can be electrically connected to generate an amount of electrical energy that is provided to another system (e.g., an electric vehicle). The battery pack can also include various control and / or protection systems, such as, for example, a heat exchanger system (e.g., a cooling system) configured to regulate the temperature of the battery pack (as well as the individual modules and battery cells), and a battery management system configured to control the voltage of the battery pack. In some embodiments, the battery pack housing, frame, or casing can include a shield at the bottom or beneath the battery modules to protect the battery modules from external elements. In some embodiments, the battery pack can include at least one heat exchanger (e.g., cooling lines configured to distribute fluid through the battery pack or a cold plate as part of heat / temperature control or heat exchange).

[0091] In some embodiments, a battery module can collect current or power from the individual battery cells that make up the battery module and provide the current or power as an output from the battery pack. A battery module can include any number of battery cells, and a battery pack can include any number of battery modules. For example, a battery pack can have 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, or other numbers of battery modules disposed in a housing / frame / casing. In some embodiments, a battery module can include multiple sub-modules. In some embodiments, these sub-modules can be separated by heat exchangers configured to regulate or control the temperature of the individual battery modules. For example, a battery module can include an upper battery sub-module and a lower battery sub-module. These sub-modules can be separated by a heat exchanger, such as a cold plate between the upper and lower battery sub-modules.

[0092] Battery packs can come in all shapes and sizes. For example, FIGS. 12-14 illustrate battery packs 120 of three different shapes. As shown in FIGS. 12-14, the battery packs 120 can include or define multiple areas, slots, holders, receptacles, etc. for positioning battery modules. Battery modules can be provided in all shapes and sizes. For example, battery modules can be square, rectangular, circular, triangular, symmetrical, or asymmetrical. In some examples, battery modules within a single battery pack can be different shapes. Similarly, a battery module can include or define multiple areas, slots, holders, receptacles, etc. for multiple battery cells.

[0093] 15 illustrates an example cross-sectional view 700 of an electric vehicle 705 including at least one battery pack 120. The electric vehicle may include, but is not limited to, an electric truck, an electric sport utility vehicle (SUV), an electric delivery van, an electric car, an electric vehicle, an electric motorcycle, an electric scooter, an electric passenger vehicle, an electric passenger or commercial truck, a hybrid vehicle, or other vehicles such as a marine or air transport vehicle, an airplane, a helicopter, a submarine, a boat, or a drone, among other possibilities. The electric vehicle may be fully electric or partially electric (e.g., a plug-in hybrid), and further, the electric vehicle may be fully autonomous, partially autonomous, or unmanned. In addition, the electric vehicle may also be human-operated or non-autonomous.

[0094] The electric vehicle 705 can be equipped with a battery pack 120 including battery modules 110 (or, in other embodiments, no arrangement in modules) having battery cells (100, 200, and / or 300) for powering the electric vehicle. The electric vehicle 705 can include a chassis 725 (e.g., a frame, an internal frame, or a support structure). The chassis 725 can support various components of the electric vehicle 705. In some embodiments, the chassis 725 can span a front portion 730 (e.g., a hood or bonnet portion), a body portion 735, and a rear portion 740 (e.g., a trunk, payload, or boot portion) of the electric vehicle 705. The battery pack 120 can be mounted or installed within the electric vehicle 705. For example, the battery pack 120 can be mounted on the chassis 725 of the electric vehicle 705 in one or more of the front portion 730, the body portion 735, or the rear portion 740. In some embodiments, battery pack 120 can include or be connected to at least one bus bar, e.g., a current collector element. For example, first bus bar 745 and second bus bar 750 can include an electrically conductive material to connect or otherwise electrically couple battery pack 120 (and / or battery modules 110 or battery cells 100, 200, and / or 300) to other electrical components of electric vehicle 705 to provide power to various systems or components of electric vehicle 705. In some embodiments, battery pack 120 can also be used as an energy storage system to power a building, such as a residence or commercial building.

[0095] As used herein, "or" is inclusive and not exclusive, unless expressly indicated otherwise or dictated otherwise by context. Thus, as used herein, "A or B" means "A, B, or both," unless expressly indicated otherwise or dictated otherwise by context. Furthermore, "and" is both jointly and severally, unless expressly indicated otherwise or dictated otherwise by context. Thus, as used herein, "A and B" means "A and B together or severally," unless expressly indicated otherwise or dictated otherwise by context.

[0096] The scope of the present disclosure encompasses all changes, substitutions, variations, alterations, and modifications to the exemplary embodiments described or illustrated herein that would be understood by a person skilled in the art. The scope of the present disclosure is not limited to the exemplary embodiments described or illustrated herein. Furthermore, although the present disclosure describes and illustrates each embodiment herein as including particular components, elements, features, functions, operations, or steps, any of these embodiments may include any combination or permutation of any of the components, elements, features, functions, operations, or steps described or illustrated anywhere herein that would be understood by a person skilled in the art. Furthermore, any reference in the appended claims to a device or system, or a component of a device or system, being adapted, arranged, capable, configured, enabled, operative, or acting to perform a particular function encompasses that device, system, or component, or that particular function, as long as the device, system, or component is so adapted, arranged, capable, configured, enabled, operative, or acting. Additionally, although this disclosure describes or illustrates particular embodiments as providing certain advantages, the particular embodiments may provide none, some, or all of these advantages. The present invention includes the following embodiments. [Claim 1] An electrode for a lithium ion battery, comprising: a first lithium metal phosphate material comprising a first plurality of active material particles; a second lithium metal phosphate material comprising a second plurality of active material particles; Both the first lithium metal phosphate material and the second lithium metal phosphate material are LiMPO 4 wherein M is one or more of iron (Fe) or manganese (Mn); An electrode wherein the first lithium metal phosphate material is blended with the second lithium metal phosphate material in a weight ratio greater than 1:1. [Claim 2] 10. The electrode of claim 1, wherein a D50 of the active material particles of the first plurality of active material particles of the first lithium metal phosphate material is less than a D50 of the active material particles of the second plurality of active material particles of the second lithium metal phosphate material. [Claim 3] The electrode of claim 1 , wherein the first plurality of active material particles comprises primary active material particles. [Claim 4] The electrode of claim 1 , wherein the second plurality of active material particles comprises primary active material particles and secondary active material particles. [Claim 5] 5. The electrode of claim 4, wherein the secondary active material particles of the second lithium metal phosphate material comprise agglomerates of primary active material particles. [Claim 6] The first and second lithium metal phosphate materials are the same LiMPO 4 2. The electrode of claim 1, wherein: [Claim 7] 3. The electrode of claim 2, wherein the D50 of primary active material particles of the first plurality of active material particles of the first lithium metal phosphate material is between 150 nanometers and 2 micrometers. [Claim 8] 3. The electrode of claim 2, wherein the D50 of secondary active material particles of the second plurality of active material particles of the second lithium metal phosphate material is 1 to 20 micrometers. [Claim 9] 10. The electrode of claim 1, wherein the combination of the first lithium metal phosphate material and the second lithium metal phosphate material comprises 0.5 to 3 wt. % carbon. [Claim 10] 10. The electrode of claim 1 having a resistivity of 600 ohm-cm or less. [Claim 11] 10. The electrode of claim 1, wherein the combination of the first lithium metal phosphate material and the second lithium metal phosphate material has a tap density of 0.8 g / cc or greater. [Claim 12] 10. The electrode of claim 1, wherein the first lithium metal phosphate material is blended with the second lithium metal phosphate material in a weight ratio greater than 3:2. [Claim 13] 10. The electrode of claim 1, wherein the first lithium metal phosphate material is blended with the second lithium metal phosphate material in a weight ratio greater than 3:1. [Claim 14] 10. The electrode of claim 1, having an electrode press density of 1.8 to 2.8 g / cc. [Claim 15] The D50 of primary active material particles of the first plurality of active material particles of the first lithium metal phosphate material is 150 nanometers or greater, and the surface area of the primary active material particles of the first plurality of active material particles of the first lithium metal phosphate material is 15 m or greater. 2 3. The electrode according to claim 2, wherein the .lambda. / g or less. [Claim 16] 3. The electrode of claim 2, wherein the D50 of at least one of primary active material particles of the first plurality of active material particles of the first lithium metal phosphate material or primary active material particles of the second plurality of active material particles of the second lithium metal phosphate material is less than or equal to 350 nanometers. [Claim 17] 3. The electrode of claim 2, wherein the D50 of primary active material particles of the first plurality of active material particles of the first lithium metal phosphate material is less than or equal to 350 nanometers. [Claim 18] A rechargeable lithium-ion battery, An electrode, a first lithium metal phosphate material comprising a first plurality of active material particles; a second lithium metal phosphate material comprising a second plurality of active material particles; Both the first lithium metal phosphate material and the second lithium metal phosphate material are LiMPO 4 wherein M is one or more of iron (Fe) or manganese (Mn); 1. A rechargeable lithium-ion battery comprising: an electrode, wherein the first lithium metal phosphate material is blended with the second lithium metal phosphate material in a weight ratio greater than 1:1. [Claim 19] 20. An electric vehicle system comprising the rechargeable lithium ion battery of claim 18.

Claims

1. An electrode for a lithium ion battery, comprising: a first lithium metal phosphate material comprising a first plurality of active material particles; a second lithium metal phosphate material comprising a second plurality of active material particles; Both the first lithium metal phosphate material and the second lithium metal phosphate material are LiMPO ４ wherein M is one or more of iron (Fe) or manganese (Mn); the first lithium metal phosphate material is blended with the second lithium metal phosphate material in a weight ratio greater than 1:1; the first plurality of active material particles includes only primary active material particles; a D50 of primary active material particles of the first plurality of active material particles of the first lithium metal phosphate material is between 150 nanometers and 2 micrometers; an electrode wherein the D50 of the second plurality of active material particles of the second lithium metal phosphate material is between 1 and 20 micrometers.

2. 10. The electrode of claim 1, wherein a D50 of the active material particles of the first plurality of active material particles of the first lithium metal phosphate material is less than a D50 of the active material particles of the second plurality of active material particles of the second lithium metal phosphate material.

3. The electrode of claim 1 or 2, wherein the second plurality of active material particles comprises primary active material particles and secondary active material particles.

4. 4. The electrode of claim 3, wherein the secondary active material particles of the second lithium metal phosphate material comprise agglomerates of primary active material particles.

5. The first and second lithium metal phosphate materials are the same LiMPO ４ 2. The electrode of claim 1 , wherein:

6. 4. The electrode of claim 3, wherein a D50 of secondary active material particles of the second plurality of active material particles of the second lithium metal phosphate material is from 1 to 20 micrometers.

7. 10. The electrode of claim 1, wherein the combination of the first lithium metal phosphate material and the second lithium metal phosphate material comprises 0.5 to 3 weight percent carbon.

8. 10. The electrode of claim 1 having a resistivity of 600 ohm-cm or less.

9. 10. The electrode of claim 1, wherein the blend of the first lithium metal phosphate material and the second lithium metal phosphate material has a tap density of 0.8 g / cc or greater.

10. 10. The electrode of claim 1, wherein the first lithium metal phosphate material is blended with the second lithium metal phosphate material in a weight ratio greater than 3:

2.

11. 10. The electrode of claim 1, wherein the first lithium metal phosphate material is blended with the second lithium metal phosphate material in a weight ratio greater than 3:

1.

12. 10. The electrode of claim 1 having an electrode press density of 1.8 to 2.8 g / cc.

13. The D50 of primary active material particles of the first plurality of active material particles of the first lithium metal phosphate material is 150 nanometers or more, and the surface area of the primary active material particles of the first plurality of active material particles of the first lithium metal phosphate material is 15 m or more. ２ 10. The electrode of claim 1, wherein the .sigma.

14. 10. The electrode of claim 1, wherein at least one of primary active material particles of the first plurality of active material particles of the first lithium metal phosphate material or primary active material particles of the second plurality of active material particles of the second lithium metal phosphate material has a D50 of 350 nanometers or less.

15. 10. The electrode of claim 1, wherein the D50 of primary active material particles of the first plurality of active material particles of the first lithium metal phosphate material is less than or equal to 350 nanometers.

16. A rechargeable lithium-ion battery, An electrode, a first lithium metal phosphate material comprising a first plurality of active material particles; a second lithium metal phosphate material comprising a second plurality of active material particles; Both the first lithium metal phosphate material and the second lithium metal phosphate material are LiMPO ４ wherein M is one or more of iron (Fe) or manganese (Mn); the first lithium metal phosphate material is blended with the second lithium metal phosphate material in a weight ratio greater than 1:1; the first plurality of active material particles includes only primary active material particles; a D50 of primary active material particles of the first plurality of active material particles of the first lithium metal phosphate material is between 150 nanometers and 2 micrometers; an electrode, wherein the second plurality of active material particles of the second lithium metal phosphate material have a D50 of 1 to 20 micrometers.

17. 17. An electric vehicle system comprising the rechargeable lithium ion battery of claim 16.

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