Steel prismatic cell with anisotropic thermal conductivity material

Abstract

The invention relates to a steel prismatic battery with anisotropic thermal conductivity materials. A prismatic battery assembly includes a battery cell, a heat dissipation element, and an anisotropic material layer. The battery cell includes a housing having a first end, a second end, a sidewall extending between the first end and the second end, and a terminal disposed at the first end. The heat dissipation element extends along the second end. The anisotropic material layer extends in a direction parallel to the sidewalls and has a first thermal conductivity level in the direction parallel to the sidewalls and a second thermal conductivity level in a direction transverse to the sidewalls. The first thermal conductivity level is greater than the second thermal conductivity level. Heat generated within the housing of the battery cell is dissipated along the anisotropic material layer in a direction parallel to the sidewalls and into the heat dissipation element.

Description

[0001] The information provided in this section is for the purpose of generally presenting the background of this disclosure. The work of the currently attributed inventors, to the extent described in this section, and in respect of aspects that may not otherwise qualify as prior art at the time of filing, is neither expressly nor impliedly acknowledged as conflicting with the prior art of this disclosure. Technical Field

[0002] This disclosure generally relates to rechargeable batteries having multiple cell units, such as prismatic or cylindrical batteries. Typically, multiple cell units in a rechargeable battery are arranged adjacent to each other. When the battery is operated (e.g., during charging or discharging), the cell units generate heat within the battery assembly, and heat can be transferred between adjacent cell units. As the temperature of the cell units increases, the efficiency and performance of the prismatic battery may degrade. Furthermore, during thermal runaway at one cell unit, heat transfer may cause thermal runaway at other cell units within the battery. Background Technology

[0003] The battery cells within a prismatic battery typically include a casing made of aluminum. Aluminum provides relatively high thermal conductivity, which is useful for transferring heat from the battery cell to heat dissipation elements. Aluminum casings are generally suitable for lithium-based battery cells because the temperatures experienced during a thermal runaway event typically do not exceed the melting point of the aluminum casing. In other words, an aluminum casing is sufficient to maintain the structural integrity of the battery casing during a thermal runaway event in a lithium-based battery. However, higher energy density batteries (such as nickel-based batteries) experience higher temperatures during thermal runaway events, and the aluminum battery cell casing included in a nickel-based battery can suffer catastrophic failures, such as sidewall cracking. Summary of the Invention

[0004] One aspect of this disclosure provides a prismatic battery assembly. The prismatic battery assembly includes a battery cell, a heat dissipation element, and an anisotropic material layer. The battery cell includes a housing having a first end, a second end, a sidewall extending between the first and second ends, and a terminal disposed at the first end. The heat dissipation element extends along the second end. The anisotropic material layer extends in a direction parallel to the sidewall and has a first thermal conductivity level in the direction parallel to the sidewall and a second thermal conductivity level in a direction transverse to the sidewall. The first thermal conductivity level is greater than the second thermal conductivity level. During operation of the prismatic battery assembly, heat generated within the housing of the battery cell is dissipated along the anisotropic material layer in a direction parallel to the sidewall and enters the heat dissipation element.

[0005] Embodiments of this aspect of the present disclosure may include one or more of the following optional features. In some examples, the anisotropic material layer extends along the outer surface of the sidewall.

[0006] In some embodiments, the anisotropic material layer extends along the inner surface of the sidewall. In other embodiments, at least one electrically insulating material layer extends along the anisotropic material layer.

[0007] In some configurations, another anisotropic material layer extends along the second end of the housing. In some other configurations, another anisotropic material layer extends along the outer surface of the second end of the housing. In some still other configurations, the anisotropic material layer has a first surface roughness, and the other anisotropic material layer has a second surface roughness, the first surface roughness being greater than the second surface roughness. In some other configurations, the other anisotropic material layer extends along the inner surface of the second end of the housing.

[0008] In some examples, the anisotropic material layer includes a polyethylene terephthalate (PET) substrate.

[0009] In some implementations, the anisotropic material layer includes graphite.

[0010] Another aspect of this disclosure provides a battery cell for a prismatic battery assembly. The battery cell includes a housing. The housing includes a first end and a second end, wherein a heat dissipation element extends along the second end. The housing also includes sidewalls and terminals, wherein the terminals are disposed at the first end. The sidewalls extend between the first and second ends, wherein an anisotropic material layer extends in a direction parallel to the sidewalls. The anisotropic material layer has a first thermal conductivity level in the direction parallel to the sidewalls and a second thermal conductivity level in a direction transverse to the sidewalls. The first thermal conductivity level is greater than the second thermal conductivity level. During operation of the prismatic battery assembly, heat generated within the housing of the battery cell is dissipated along the anisotropic material layer in a direction parallel to the sidewalls and enters the heat dissipation element.

[0011] Embodiments of this aspect of the present disclosure may include one or more of the following optional features. In some examples, the anisotropic material layer extends along the outer surface of the sidewall.

[0012] In some implementations, the anisotropic material layer extends along the inner surface of the sidewall.

[0013] In some configurations, another anisotropic material layer extends along the second end of the housing.

[0014] In some examples, the anisotropic material layer includes at least one of the following: i) graphite, and ii) a polyethylene terephthalate (PET) substrate.

[0015] Another aspect of this disclosure provides a vehicle. The vehicle includes a prismatic battery pack. The prismatic battery pack includes battery cells, a heat dissipation element, and an anisotropic material layer. The battery cell includes a housing having a first end, a second end, a sidewall extending between the first and second ends, and a terminal disposed at the first end. The heat dissipation element extends along the second end. The anisotropic material layer extends in a direction parallel to the sidewall. The anisotropic material has a first thermal conductivity level in the direction parallel to the sidewall and a second thermal conductivity level in a direction transverse to the sidewall. The first thermal conductivity level is greater than the second thermal conductivity level. During operation of the prismatic battery pack, heat generated within the housing of the battery cell is dissipated along the anisotropic material layer in a direction parallel to the sidewall and enters the heat dissipation element.

[0016] Embodiments of this aspect of the present disclosure may include one or more of the following optional features. In some examples, the anisotropic material layer extends along the outer surface of the sidewall.

[0017] In some implementations, the anisotropic material layer extends along the inner surface of the sidewall.

[0018] In some configurations, another anisotropic material layer extends along the second end of the housing.

[0019] In some examples, the anisotropic material layer includes at least one of the following: i) graphite, and ii) a polyethylene terephthalate (PET) substrate.

[0020] This invention also includes the following technical features:

[0021] 1. A prismatic battery module, comprising:

[0022] A battery cell includes a housing having a first end, a second end, a sidewall extending between the first end and the second end, and a terminal disposed at the first end;

[0023] A heat dissipation element extending along the second end;

[0024] An anisotropic material layer extends in a direction parallel to the sidewalls, the anisotropic material having a first thermal conductivity level in the direction parallel to the sidewalls and a second thermal conductivity level in a direction transverse to the sidewalls, the first thermal conductivity level being greater than the second thermal conductivity level; and

[0025] During operation of the prismatic battery assembly, heat generated within the housing of the battery cell is dissipated along the anisotropic material layer in a direction parallel to the sidewall and enters the heat dissipation element.

[0026] 2. The prismatic battery assembly according to Scheme 1, wherein the anisotropic material layer extends along the outer surface of the sidewall.

[0027] 3. The prismatic battery assembly according to Scheme 1, wherein the anisotropic material layer extends along the inner surface of the sidewall.

[0028] 4. The prismatic battery assembly according to Scheme 3, wherein at least one electrically insulating material layer extends along the anisotropic material layer.

[0029] 5. The prismatic battery assembly according to Scheme 1, wherein another anisotropic material layer extends along the second end of the housing.

[0030] 6. The prismatic battery assembly according to claim 5, wherein the other anisotropic material layer extends along the outer surface of the second end of the housing.

[0031] 7. The prism-shaped battery assembly according to Scheme 6, wherein the anisotropic material layer has a first surface roughness, and the other anisotropic material layer has a second surface roughness, wherein the first surface roughness is greater than the second surface roughness.

[0032] 8. The prismatic battery assembly according to claim 5, wherein the other anisotropic material layer extends along the inner surface of the second end of the housing.

[0033] 9. The prismatic battery assembly according to Scheme 1, wherein the anisotropic material layer comprises a polyethylene terephthalate (PET) substrate.

[0034] 10. The prismatic battery assembly according to Scheme 1, wherein the anisotropic material layer comprises graphite.

[0035] 11. A battery cell for a prismatic battery assembly, the battery cell comprising:

[0036] The housing includes:

[0037] First end,

[0038] The second end, wherein the heat dissipation element extends along the second end.

[0039] A sidewall extending between the first end and the second end, wherein an anisotropic material layer extends in a direction parallel to the sidewall, the anisotropic material having a first thermal conductivity level in the direction parallel to the sidewall and a second thermal conductivity level in a direction transverse to the sidewall, the first thermal conductivity level being greater than the second thermal conductivity level, and

[0040] A terminal is disposed at the first end; and

[0041] During operation of the prismatic battery assembly, heat generated within the housing of the battery cell is dissipated along the anisotropic material layer in a direction parallel to the sidewall and enters the heat dissipation element.

[0042] 12. The battery cell according to claim 11, wherein the anisotropic material layer extends along the outer surface of the sidewall.

[0043] 13. The battery cell according to claim 11, wherein the anisotropic material layer extends along the inner surface of the sidewall.

[0044] 14. The battery cell according to claim 11, wherein another anisotropic material layer extends along the second end of the housing.

[0045] 15. The battery cell according to claim 11, wherein the anisotropic material layer comprises at least one of the following: i) graphite, and ii) a polyethylene terephthalate (PET) substrate.

[0046] 16. A vehicle comprising:

[0047] Prismatic battery module, comprising:

[0048] A battery cell includes a housing having a first end, a second end, a sidewall extending between the first end and the second end, and a terminal disposed at the first end;

[0049] A heat dissipation element extending along the second end;

[0050] An anisotropic material layer extends in a direction parallel to the sidewalls, the anisotropic material having a first thermal conductivity level in the direction parallel to the sidewalls and a second thermal conductivity level in a direction transverse to the sidewalls, the first thermal conductivity level being greater than the second thermal conductivity level; and

[0051] During operation of the prismatic battery assembly, heat generated within the housing of the battery cell is dissipated along the anisotropic material layer in a direction parallel to the sidewall and enters the heat dissipation element.

[0052] 17. The vehicle according to claim 16, wherein the anisotropic material layer extends along the outer surface of the sidewall.

[0053] 18. The vehicle according to claim 16, wherein the anisotropic material layer extends along the inner surface of the sidewall.

[0054] 19. The vehicle according to claim 16, wherein another anisotropic material layer extends along the second end of the outer shell.

[0055] 20. The vehicle according to claim 16, wherein the anisotropic material layer comprises at least one of the following: i) graphite, and ii) a polyethylene terephthalate (PET) substrate. Attached Figure Description

[0056] The accompanying drawings described herein are for illustrative purposes only and are not intended to limit the scope of this disclosure.

[0057] Figure 1 This is a perspective view of a vehicle including a prismatic battery pack according to this disclosure;

[0058] Figure 2A This is a cross-sectional view of the prismatic battery assembly according to this disclosure;

[0059] Figure 2B yes Figure 2A A cross-sectional view of a portion of a battery cell in a prismatic battery assembly, showing the thermal conductivity gradient of an anisotropic material layer disposed at the battery cell.

[0060] Figure 2C This is a graph showing the temperature gradient of a prismatic battery assembly having an aluminum casing and an electrolyte at the bottom portion of the battery cell.

[0061] Figure 2D This is a graph showing the temperature gradient of a prismatic battery assembly having a steel casing and an electrolyte at the bottom portion of the battery cell;

[0062] Figure 2E It is shown Figure 2B A graph showing the temperature gradient of a battery cell, where the electrolyte is located at the bottom portion of the battery cell and the thickness of the anisotropic material layer is 0.1 mm.

[0063] Figure 2F It is a graph showing the temperature gradient of the battery cells in a prismatic battery assembly having an aluminum casing and air at the bottom portion of the battery cells;

[0064] Figure 2G It is a graph showing the temperature gradient of the battery cells in a prismatic battery assembly, which has a steel casing and air at the bottom of the battery cells;

[0065] Figure 2H It is shown Figure 2BA graph showing the temperature gradient of a battery cell, where there is air at the bottom portion of the battery cell and the thickness of the anisotropic material layer is 0.1 mm;

[0066] Figure 3A This is a cross-sectional view of a portion of a battery cell in a prismatic battery assembly according to the present disclosure;

[0067] Figure 3B yes Figure 3A A cross-sectional view of a portion of a battery cell in a prismatic battery assembly, showing the thermal conductivity gradient of an anisotropic material layer disposed at the battery cell.

[0068] Figure 3C It is shown Figure 3B A graph showing the temperature gradient of a battery cell, where there is air at the bottom portion of the battery cell and the thickness of the anisotropic material layer is 0.05 mm.

[0069] Figure 3D It is shown Figure 3B A graph showing the temperature gradient of a battery cell, where there is air at the bottom portion of the battery cell and the thickness of the anisotropic material layer is 0.1 mm;

[0070] Figure 3E It is a comparison Figure 3B A graph showing the highest operating temperature of a battery cell in an anisotropic material layer of varying thickness, wherein air is present in the bottom portion of the battery cell and an electrolyte is present in the bottom portion of the battery cell.

[0071] Figure 4A This is a cross-sectional view of a portion of a battery cell in a prismatic battery assembly according to the present disclosure;

[0072] Figure 4B yes Figure 4A A cross-sectional view of a portion of a battery cell in a prismatic battery assembly, showing the thermal conductivity gradient of an anisotropic material layer disposed at the battery cell.

[0073] Figure 4C It is shown Figure 4B A graph showing the temperature gradient of a battery cell, where there is air at the bottom portion of the battery cell and the thickness of the anisotropic material layer is 0.05 mm.

[0074] Figure 4D It is shown Figure 4B A graph showing the temperature gradient of a battery cell, where there is air at the bottom portion of the battery cell and the thickness of the anisotropic material layer is 0.1 mm;

[0075] Figure 4E It is a comparison Figure 4BA graph showing the highest operating temperature of a battery cell in an anisotropic material layer of varying thickness, wherein air is present in the bottom portion of the battery cell and an electrolyte is present in the bottom portion of the battery cell.

[0076] Figure 4F It is shown Figure 2B , Figure 3B and Figure 4B The highest operating temperature of the battery cell at an anisotropic material layer of varying thickness.

[0077] Figure 5 This is a cross-sectional view of a portion of a battery cell in a prismatic battery assembly according to the present disclosure; and

[0078] Figure 6 This is a cross-sectional view of a portion of a battery cell in a prismatic battery assembly according to the present disclosure;

[0079] The corresponding reference numerals run throughout the accompanying drawings to indicate the corresponding parts. Detailed Implementation

[0080] The example configuration will now be described more fully with reference to the accompanying drawings. The example configuration is provided so that this disclosure will be thorough and will fully convey the scope of this disclosure to those skilled in the art. Specific details, such as examples of particular components, apparatus, and methods, are set forth to provide a thorough understanding of the configuration of this disclosure. It will be apparent to those skilled in the art that specific details are not required, the example configuration may be embodied in many different forms, and the specific details and example configuration should not be construed as limiting the scope of this disclosure.

[0081] The terminology used herein is for the purpose of describing specific exemplary configurations only and is not intended to be limiting. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise. The terms “comprising,” “including,” “containing,” and “having” are inclusive and therefore specify the presence of features, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof. Unless expressly identified as an order of execution, the method steps, processes, and operations described herein are not to be construed as requiring performance in the specific order discussed or illustrated. Additional or alternative steps may be employed.

[0082] When an element or layer is referred to as being “on”, “joined to,” “connected to,” “attached to,” or “linked to” another element or layer, it may be directly on, joined to, attached to, or linked to the other element or layer, or there may be intermediate elements or layers present. In contrast, when an element is referred to as being “directly on”, “directly joined to,” “directly connected to,” “directly attached to,” or “directly linked to” another element or layer, there may be no intermediate elements or layers present. Other terms used to describe relationships between elements should be interpreted in a similar manner (e.g., “between” vs. “directly between,” “adjacent” vs. “directly adjacent,” etc.). As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed items.

[0083] In this document, the terms “first,” “second,” “third,” etc., may be used to describe various elements, components, regions, layers, and / or sections. These elements, components, regions, layers, and / or sections should not be limited by these terms. These terms are used only to distinguish one element, component, region, layer, or section from another. Unless the context clearly indicates otherwise, terms such as “first,” “second,” and other numerical terms do not imply order or sequence. Therefore, without departing from the teachings of the example configuration, the first element, component, region, layer, or section discussed below may be referred to as the second element, component, region, layer, or section.

[0084] In this application (including the following limitations), the term "module" may be replaced by the term "circuit". The term "module" may refer to, be part of, or include: Application Specific Integrated Circuit (ASIC); digital, analog, or mixed-signal analog / digital discrete circuit; digital, analog, or mixed-signal analog / digital integrated circuit; combinational logic circuit; Field Programmable Gate Array (FPGA); processor (shared, dedicated, or group) for executing code; memory (shared, dedicated, or group) for storing code executed by the processor; other suitable hardware components that provide the described functionality; or combinations of some or all of the above, such as in a system-on-a-chip.

[0085] The term "code" as used above can include software, firmware, and / or microcode, and can refer to programs, routines, functions, classes, and / or objects. The term "shared processor" covers a single processor that executes some or all of the code from multiple modules. The term "group processor" covers processors that, in combination with additional processors, execute some or all of the code from one or more modules. The term "shared memory" covers a single memory that stores some or all of the code from multiple modules. The term "group memory" covers memory that, in combination with additional memory, stores some or all of the code from one or more modules. The term "memory" can be a subset of the term "computer-readable medium." The term "computer-readable medium" does not cover transient electrical or electromagnetic signals propagated through a medium, and therefore can be considered tangible and non-transitory memory. Non-limiting examples of non-transitory memory include tangible computer-readable media, including non-volatile memory, magnetic storage devices, and optical storage devices.

[0086] The apparatus and methods described in this application may be implemented, in whole or in part, by one or more computer programs executed by one or more processors. The computer program includes processor-executable instructions stored on at least one non-transitory, tangible, computer-readable medium. The computer program may also include and / or depend on stored data.

[0087] A software application (i.e., a software resource) can refer to computer software that causes a computing device to perform a task. In some examples, a software application may be referred to as an "application," "app," or "program." Example applications include, but are not limited to, system diagnostic applications, system management applications, system maintenance applications, word processing applications, spreadsheet applications, messaging applications, media streaming applications, social networking applications, and gaming applications.

[0088] Non-transitory memory can be a physical device used to store programs (e.g., instruction sequences) or data (e.g., program state information) on a temporary or permanent basis for use by a computing device. Non-transitory memory can be volatile and / or non-volatile addressable semiconductor memory. Examples of non-volatile memory include, but are not limited to, flash memory and read-only memory (ROM) / programmable read-only memory (PROM) / erasable programmable read-only memory (EPROM) / electronically erasable programmable read-only memory (EEPROM) (e.g., commonly used in firmware, such as boot programs). Examples of volatile memory include, but are not limited to, random access memory (RAM), dynamic random access memory (DRAM), static random access memory (SRAM), phase-change memory (PCM), and magnetic disks or magnetic tapes.

[0089] These computer programs (also referred to as programs, software, software applications, or code) include machine instructions for a programmable processor and can be implemented in high-level programming and / or object-oriented programming languages ​​and / or in assembly / machine language. As used herein, the terms “machine-readable medium” and “computer-readable medium” refer to any computer program product, non-transitory computer-readable medium, device, and / or apparatus (e.g., disk, optical disk, memory, programmable logic device (PLD)) used to provide machine instructions and / or data to a programmable processor, including machine-readable media that receive machine instructions as machine-readable signals. The term “machine-readable signal” refers to any signal used to provide machine instructions and / or data to a programmable processor.

[0090] Various implementations of the systems and techniques described herein can be implemented in digital electronic and / or optical circuit systems, integrated circuit systems, specially designed ASICs (Application-Specific Integrated Circuits), computer hardware, firmware, software, and / or combinations thereof. These various implementations can also include implementations in one or more computer programs executable and / or interpretable on a programmable system comprising at least one programmable processor, which may be dedicated or general-purpose and coupled to receive data and instructions from a storage system, at least one input device, and at least one output device, and to transfer data and instructions to the storage system, at least one input device, and at least one output device.

[0091] The processes and logic flows described in this specification can be executed by one or more programmable processors (also known as data processing hardware) that execute one or more computer programs to perform functions by manipulating input data and generating output. These processes and logic flows can also be executed by special-purpose logic circuit systems (e.g., FPGAs (Field-Programmable Gate Arrays) or ASICs (Application-Specific Integrated Circuits)). For example, processors suitable for executing computer programs include both general-purpose and special-purpose microprocessors, as well as any type of digital computer and any one or more processors. Typically, the processor receives instructions and data from read-only memory or random access memory, or both. Essential components of a computer are the processor for executing instructions and one or more memory devices for storing instructions and data. Typically, a computer will also include one or more mass storage devices (e.g., magnetic disks, magneto-optical disks, or optical disks) for storing data, or operatively coupled to receive data from or transfer data to such mass storage devices. However, a computer does not need to have such devices. Computer-readable media suitable for storing computer program instructions and data include all forms of non-volatile memory, media, and memory devices, including, for example, semiconductor memory devices such as EPROM, EEPROM, and flash memory devices; magnetic disks, such as internal hard disks or removable disks; magneto-optical disks; and CD-ROM and DVD-ROM disks. The processor and memory may be supplemented by or incorporated into a dedicated logic circuit system.

[0092] To provide interaction with a user, one or more aspects of this disclosure can be implemented on a computer having a display device for displaying information to the user (e.g., a CRT (cathode ray tube), LCD (liquid crystal display) monitor, or touchscreen) and optionally a keyboard and pointing device (e.g., a mouse or trackball) that the user can use to provide input to the computer. Other types of devices can also be used to provide interaction with the user; for example, feedback provided to the user can be any form of sensory feedback, such as visual feedback, auditory feedback, or tactile feedback; and input from the user can be received in any form, including sound, speech, or tactile input. Additionally, the computer can interact with the user by sending documents to and receiving documents from the device used by the user; for example, by sending web pages to a web browser on the user's client device in response to a request received from a web browser.

[0093] refer to Figure 1-2BThe vehicle 10 includes a rechargeable battery assembly 12 that powers one or more components of the vehicle 10. For example, the vehicle 10 may be an electric vehicle, a plug-in hybrid vehicle, or a hybrid vehicle, and the rechargeable battery assembly 12 may be a prismatic battery, such as a lithium-ion battery or a nickel-metal hydride battery, which at least partially powers the propulsion system of the vehicle 10. Therefore, the prismatic battery assembly 12 receives current (e.g., from an external charging device or an onboard charging system) to charge the prismatic battery assembly 12, and the prismatic battery assembly 12 discharges current to power components of the vehicle 10.

[0094] The prismatic battery assembly 12 includes a plurality of battery cells 14 that receive and discharge current during operation of the prismatic battery assembly 12. Each battery cell 14 includes a housing 16 or casing that houses the electrodes or electrode stacks of the battery cell 14. When the prismatic battery assembly 12 is operated, heat is generated within the housing 16 of the battery cell 14.

[0095] The housing 16 is formed of steel or a steel alloy and includes a first end wall 18 and a second end wall 20 opposite to the first end wall 18. The housing 16 also includes one or more side walls 22 extending between the first end wall 18 and the second end wall 20. For example, the housing 16 may have cylindrical side walls extending between the first end wall 18 and the second end wall 20, or the housing 16 may include four side walls extending between the first end wall 18 and the second end wall 20 to form a cuboid-shaped battery cell 14. In the illustrated example, the housing 16 includes a terminal 24 disposed at the first end wall 18. The terminal 24 provides an electrical connection between the prismatic battery assembly 12 and electrical components included in the vehicle 10.

[0096] The first end wall 18 of the housing 16 includes an inner surface 26 and an outer surface 28 opposite to the inner surface 26. The inner surface 26 of the first end wall 18 is mated with the electrode stack of the battery cell 14, while the outer surface 28 of the first end wall 18 faces the outside of the battery cell 14. Similarly, the second end wall 20 of the housing 16 includes an inner surface 30 and an outer surface 32 opposite to the inner surface 30. The inner surface 30 of the second end wall 20 is mated with the battery cell 14, while the outer surface 32 of the second end wall 20 faces the outside of the battery cell 14. In a similar manner, the side wall 22 includes an inner surface 34 and an outer surface 36 opposite to the inner surface 34. The inner surface 34 of the side wall 22 is mated with the electrode stack of the battery cell 14, while the outer surface 36 of the side wall 22 faces the outside of the battery cell 14.

[0097] A thermal interface material (TIM) 38 is disposed below the battery cell 14 of the prismatic battery assembly 12 and thermally connects the battery cell 14 to a heat dissipation element or cold plate 40 for regulating the temperature of the prismatic battery assembly 12. For example, the TIM 38 may abut against the outer surface 32 of the second end wall 20 of the battery cell 14 and be disposed between the cold plate 40 and the battery cell 14. The TIM 38 and the cold plate 40 may cooperate to act as a heat sink or heat diffuser to achieve efficient heat transfer from the battery cell 14 during operation.

[0098] refer to Figure 2A-2H A thermal runaway barrier (TRB) 42 is disposed between the outer surface 36 of the sidewall 22 of the housing 16 and the adjacent battery cell 14. In other words, the TRB 42 acts as a barrier between each battery cell 14 to limit thermal transfer between the battery cells 14. In this respect, the TRB 42 helps to reduce the potential for thermal runaway events to propagate between the battery cells 14 of the prismatic battery assembly 12.

[0099] To further resist damage to the battery cells 14 of the prismatic battery assembly 12 during a thermal runaway event, the casing 16 is formed of steel or a steel alloy. The melting temperature of steel and steel alloys is typically higher than that of lithium-based and nickel-based batteries, or other battery types with higher energy densities, during a thermal runaway event. Therefore, the prismatic battery assembly 12 accommodates battery cells 14 with high energy density (e.g., nickel-based electrode stacks). Furthermore, the use of steel or a steel alloy allows for a reduction in the thickness of the end walls 18, 20 and the side walls 22, enabling the walls of the casing 16 to have a corresponding thickness between approximately 0.2 mm and 0.4 mm.

[0100] At the start of the lifecycle of the prismatic battery assembly 12, an electrolyte material may be disposed between the lower end of the electrode stack and the inner surface 30 of the second end wall 20 of the battery cell 14. The electrolyte material assists in transferring heat from the electrode stack to the second end wall 20 and towards the TIM 38 and the cold plate 40. During operation of the prismatic battery assembly 12, the electrolyte material may be consumed, and an air gap may be formed between the electrode stack and the inner surface 30 of the second end wall 20. This air gap may not transfer heat between the electrode stack and the second end wall 20 as efficiently as the electrolyte material, resulting in a higher operating temperature for the prismatic battery assembly 12.

[0101] Because steel and steel alloys have lower thermal conductivity than, for example, aluminum, an anisotropic material layer 44 is disposed on the outer surface 36 of the sidewall 22 and extends in a direction parallel to the sidewall 22. In other words, the anisotropic material layer 44 is positioned between the outer surface 36 of the sidewall 22 and the TRB 42. The anisotropic material layer 44 comprises graphite and is configured to dissipate heat generated within the battery cell 14. For example, heat generated within the housing 16 is at least partially dissipated through the sidewall 22 and into the anisotropic material layer 44. The anisotropic material layer 44 is configured to allow a first-stage heat transfer in a direction parallel to the anisotropic material layer 44 extending along the sidewall 22 and to allow a second-stage heat transfer in at least one direction transverse to the anisotropic material layer 44 extending along the sidewall 22. In other words, the anisotropic material layer 44 guides heat along the sidewall 22 toward the TIM 38 and the cold plate 40 for further dissipation from the battery cell 14, and the anisotropic material layer 44 resists heat transfer from the sidewall 22 of the housing 16 toward the adjacent battery cell 14.

[0102] In other words, the anisotropic material layer 44 has a first thermal conductivity level 50 extending in a direction parallel to the sidewall 22. Additionally, the anisotropic material layer 44 has a second thermal conductivity level 52 extending in a direction transverse to the sidewall 22. (See reference...) Figure 2B The first thermal conductivity level 50 is indicated by an arrow pointing in a direction parallel to the sidewall 22, and the second thermal conductivity level 52 is indicated by an arrow pointing in a direction perpendicular to the sidewall 22. In other examples, the anisotropic material layer 44 may, to varying degrees, resist and guide heat transfer relative to the wall of the housing 16 in any suitable direction. In the illustrated example, the first thermal conductivity level 50 is greater than the second thermal conductivity level 52. In other words, heat transfer along the direction parallel to the sidewall 22 occurs more efficiently and faster than in the direction transverse to the sidewall 22. For example, the first thermal conductivity level 50 may be at or near 1800 watts / meter-Kelvin (W / mK), while the second thermal conductivity level 52 may be at or near 15 W / mK.

[0103] During operation of the prismatic battery assembly 12, heat generated within the battery cell 14 is transferred through the sidewall 22 and ultimately reaches the anisotropic material layer 44. A first thermal conductivity level 50 allows for rapid and efficient heat transfer through the anisotropic material layer 44 in a direction parallel to the sidewall 22 from the first end wall 18 of the housing 16 toward the second end wall 20 of the housing 16. A second thermal conductivity level 52 resists heat transfer through the anisotropic material layer 44 in a direction transverse to the sidewall 22. In this respect, heat is allowed to travel from the battery cell 14 into the anisotropic material layer 44 and toward the TIM 38 and the cold plate 40. Because the second thermal conductivity level 52 is lower than the first thermal conductivity level 50, heat transfer through the anisotropic material layer 44 in a direction transverse to the sidewall 22 is resisted. In this respect, heat is generally prevented from traveling into the TRB 42, as the vast majority of the generated heat travels into the TIM 38 and the cold plate 40.

[0104] The anisotropic material layer 44 allows the prismatic battery assembly 12 with its thin steel casing 16 to operate at temperatures similar to those experienced by batteries with typically thicker aluminum casings. For example, and as... Figure 2C-2H As shown, at point 100, a rechargeable battery having a battery cell with an aluminum casing of approximately 0.6 mm thickness can operate at a temperature of approximately 44.7 degrees Celsius at the beginning of the battery life cycle (i.e., where the electrolyte is present), and at point 106 at approximately 50.4 degrees Celsius near the end of the battery life cycle (i.e., where the electrolyte is consumed and air gaps are present). At point 102, a rechargeable battery having a steel casing with a steel casing of approximately 0.3 mm thickness and without an anisotropic material layer can operate at approximately 49.3 degrees Celsius at the beginning of the battery life cycle, and at point 108 at approximately 53.4 degrees Celsius near the end of the battery life cycle. At point 104, a prismatic battery assembly 12 having a battery cell 14 with a steel casing 16 of approximately 0.3 mm thickness can operate at approximately 45.8 degrees Celsius at the beginning of the battery life cycle, and at point 110 at approximately 48.1 degrees Celsius near the end of the battery life cycle.

[0105] Furthermore, the prismatic battery assembly 12 includes a polypropylene (PP) layer 46 and a polyethylene terephthalate (PET) layer 48. The PP layer 46 is disposed on the inner surface 34 of the sidewall 22 of the housing 16 and the inner surface 30 of the second end wall 20. The PET layer 48 is disposed on the outer surface 36 of the sidewall 22 of the housing 16 and the outer surface 32 of the second end wall 20. The PP layer 46 acts as an electrically insulating material and is configured to isolate components (such as electrode stacks) contained within the battery cell 14 from the housing 16. Similarly, the PET layer 48 is configured to electrically insulate the battery cell 14 and provide mechanical and chemical stability to the battery cell 14. In this configuration, the PET layer 48 is disposed between the housing 16 and the anisotropic material layer 44.

[0106] In some examples, the prismatic battery assembly includes a second anisotropic material layer located between the lower end wall and the TIM. This second anisotropic material layer may extend beneath the multiple battery cells to allow heat generated by the battery cells to diffuse more uniformly along the TIM, resulting in more efficient heat transfer to the TIM and away from the battery cells. For example, and particularly refer to… Figures 3A-3E The prismatic battery assembly 12a includes an anisotropic horizontal or lower layer of material located between the second end wall 20 and TIM 38. Given that the components associated with the prismatic battery assembly 12 are substantially similar in structure and function, similar reference numerals are used below and in the accompanying drawings to identify similar components, while similar reference numerals including alphanumeric extensions are used to identify those modified components.

[0107] The prismatic battery assembly 12a includes a housing 16 formed of steel or a steel alloy, and the housing includes a first end wall and a second end wall 20 opposite to the first end wall. The housing 16 also includes one or more side walls 22 extending between the first end wall and the second end wall 20. The first end wall of the housing 16 includes an inner surface and an outer surface opposite to the inner surface. The inner surface of the first end wall is abuttable to the electrode stack of the battery cell 14, while the outer surface of the first end wall faces the outside of the battery cell 14. Similarly, the second end wall 20 of the housing 16 includes an inner surface 30 and an outer surface 32 opposite to the inner surface 30. The inner surface 30 of the second end wall 20 abuts to the battery cell 14, while the outer surface 32 of the second end wall 20 faces the outside of the battery cell 14. In a similar manner, the side wall 22 includes an inner surface 34 and an outer surface 36 opposite to the inner surface 34. The inner surface 34 of the side wall 22 abuts to the electrode stack of the battery cell 14, while the outer surface 36 of the side wall 22 faces the outside of the battery cell 14.

[0108] A thermal interface material (TIM) 38 is disposed below the battery cell 14 of the prismatic battery assembly 12a and thermally connects the battery cell 14 to a heat dissipation element or cold plate 40 for regulating the temperature of the prismatic battery assembly 12a. For example, the TIM 38 may abut against the outer surface 32 of the second end wall 20 of the battery cell 14 and be disposed between the cold plate 40 and the battery cell 14. The TIM 38 and the cold plate 40 may cooperate to act as a heat sink or heat diffuser to achieve efficient heat transfer from the battery cell 14 during operation.

[0109] A thermal runaway barrier (TRB) 42 is disposed between the outer surface 36 of the sidewall 22 of the housing 16 and the adjacent battery cell 14. In other words, the TRB 42 acts as a barrier between each battery cell 14 to limit thermal transfer between the battery cells 14. In this respect, the TRB 42 helps to reduce the potential for thermal runaway events to propagate between the battery cells 14 of the prismatic battery assembly 12a.

[0110] The prismatic battery assembly 12a includes a first anisotropic material layer 44a disposed on the outer surface 36 of the sidewall 22 and extending in a direction parallel to the sidewall 22. Furthermore, a second anisotropic material layer 58a is disposed on the outer surface 32 of the second end wall 20 and extends in a direction parallel to the second end wall 20. In other words, the first anisotropic material layer 44a is positioned between the outer surface 36 of the sidewall 22 and TRB 42, and the second anisotropic material layer 58a is positioned between the outer surface 32 of the second end wall 20 and TIM 38. The anisotropic material layers 44a and 58a comprise graphite and are configured to dissipate heat generated within the battery cell 14. For example, heat generated within the housing 16 is at least partially dissipated through the sidewall 22 and into the first anisotropic material layer 44a. Additionally, the heat generated within the housing 16 is at least partially dissipated through the second end wall 20 and into the second anisotropic material layer 58a. The second anisotropic material layer 58a may extend beneath one or more of the battery cells 14 of the prismatic battery assembly 12a to uniformly distribute the heat generated by the battery cells 14 across the TIM 38.

[0111] The first anisotropic material layer 44a is configured to allow a first-stage heat transfer along a direction parallel to the first anisotropic material layer 44a along the sidewall 22 and to allow a second-stage heat transfer along a direction transverse to the first anisotropic material layer 44a along the sidewall 22. In other words, the first anisotropic material layer 44a directs heat along the sidewall 22 toward the TIM 38 and the cold plate 40 for further dissipation from the battery cell 14, and the first anisotropic material layer 44a resists heat transfer from the sidewall 22 of the housing 16 toward the adjacent battery cell 14.

[0112] Additionally, the second anisotropic material layer 58a is configured to allow a third-level heat transfer along a direction parallel to the second anisotropic material layer 58a along the second end wall 20 and a fourth-level heat transfer along a direction transverse to the second anisotropic material layer 58a along the second end wall 20. In other words, the second anisotropic material layer 58a guides heat along the second end wall 20 and along the TIM 38 and cold plate 40 for further dissipation from the battery cell 14. Although the third-level heat transfer is greater than the fourth-level heat transfer, the positioning of the second anisotropic material layer 58a against the large surface area of ​​the TIM 38 provides space for sufficient heat transfer into the TIM 38 through the second anisotropic material layer 58a. In other words, heat diffuses rapidly during the third-level heat transfer to diffuse heat across the large surface area of ​​the TIM 38 and achieve sufficient heat transfer into the TIM 38.

[0113] In other words, the first anisotropic material layer 44a has a first thermal conductivity level 50a extending in a direction parallel to the sidewall 22. Additionally, the first anisotropic material layer 44a has a second thermal conductivity level 52a extending in a direction transverse to the sidewall 22. (See reference...) Figure 3A and Figure 3B The first thermal conductivity level 50a is indicated by an arrow pointing in a direction parallel to the sidewall 22, and the second thermal conductivity level 52a is indicated by an arrow pointing in a direction perpendicular to the sidewall 22. In other examples, the first anisotropic material layer 44a may, to varying degrees, resist and guide heat transfer relative to the wall of the housing 16 in any suitable direction. In the illustrated example, the first thermal conductivity level 50a is greater than the second thermal conductivity level 52a. In other words, heat transfer along the direction parallel to the sidewall 22 occurs more efficiently and faster than in the direction transverse to the sidewall 22. For example, the first thermal conductivity level 50a may be at or near 1800 watts / meter-Kelvin (W / mK), while the second thermal conductivity level 52a may be at or near 15 W / mK.

[0114] The second anisotropic material layer 58a has a third thermal conductivity level 54a extending in a direction parallel to the second end wall 20. Additionally, the second anisotropic material layer 58a has a fourth thermal conductivity level 56a extending in a direction transverse to the second end wall 20. The third thermal conductivity level 54a is indicated by an arrow pointing in a direction parallel to the second end wall 20, and the fourth thermal conductivity level 56a is indicated by an arrow pointing perpendicular to the second end wall 20. In other examples, the second anisotropic material layer 58a may resist and guide heat transfer relative to the wall of the housing 16 in any suitable direction to varying degrees. In the illustrated example, the third thermal conductivity level 54a is greater than the fourth thermal conductivity level 56a. In other words, heat transfer in a direction parallel to the second end wall 20 occurs more efficiently and faster than in a direction transverse to the second end wall 20. However, heat diffuses rapidly across the large surface area of ​​the TIM 38, thus achieving sufficient heat transfer along the second anisotropic material layer 58a and into the TIM 38. The third thermal conductivity level 54a can be at or near 1800 W / mK, while the fourth thermal conductivity level 56a can be at or near 15 W / mK.

[0115] During operation of the prismatic battery assembly 12a, heat generated within the battery cell 14 is transferred via the sidewalls 22 and the second endwalls 20, ultimately reaching the first anisotropic material layer 44a and the second anisotropic material layer 58a. A first thermal conductivity level 50a enables rapid and efficient heat transfer from the first endwall of the housing 16 toward the second endwall 20 of the housing 16 through the first anisotropic material layer 44a in a direction parallel to the sidewalls 22. A second thermal conductivity level 52a inhibits heat transfer through the first anisotropic material layer 44a in a direction transverse to the sidewalls 22. Furthermore, a third thermal conductivity level 54a enables rapid and efficient heat transfer through the second anisotropic material layer 58a in a direction parallel to the second endwalls 20. A fourth thermal conductivity level 56a inhibits heat transfer through the second anisotropic material layer 58a in a direction transverse to the second endwalls 20. However, heat can diffuse across the large surface area of ​​the TIM 38 to transfer into the TIM 38. In this respect, heat can travel from the battery cell 14 into the anisotropic material layers 44a and 58a, and towards the TIM 38 and the cold plate 40. Due to the second thermal conductivity level 52a being much lower than the first thermal conductivity level 50a, heat transfer through the first anisotropic material layer 44a in the direction transverse to the sidewall 22 is resisted. In this respect, heat is generally prevented from traveling into the TRB 42, as the vast majority of the generated heat travels into the TIM 38 and the cold plate 40.

[0116] The anisotropic material layers 44a and 58a allow the prismatic battery assembly 12a with its thin steel casing 16 to operate at temperatures similar to those experienced by batteries with typically thicker aluminum casings. For example, and as... Figure 3C-3E As shown, at position 200, the prismatic battery assembly 12a having battery cell 14 (with a steel casing of approximately 0.3 mm thickness and anisotropic material layers 44a, 58a of approximately 0.05 mm thickness) can operate at approximately 46.9 degrees Celsius at the end of the battery life cycle. At position 202, the prismatic battery assembly 12a having battery cell 14 (with a steel casing 16 of approximately 0.3 mm thickness and anisotropic material layers 44a, 58a of approximately 0.1 mm thickness) can operate at approximately 46.6 degrees Celsius at the end of the battery life cycle. Generally, at position 204, the maximum operating temperature of battery cell 14 decreases with increasing thickness of anisotropic material layers 44a, 58a, eventually stabilizing when the thickness of anisotropic material layers 44a, 58a exceeds approximately 0.075 mm. Furthermore, the maximum operating temperature of battery cell 14 is higher at the end of the battery life cycle compared to the beginning of the battery life cycle.

[0117] Furthermore, the prismatic battery assembly 12a includes a polypropylene (PP) layer 46 and a polyethylene terephthalate (PET) layer 48. The PP layer 46 is disposed on the inner surface 34 of the sidewall 22 of the housing 16 and the inner surface 30 of the second end wall 20. The PET layer 48 is disposed on the outer surface 36 of the sidewall 22 of the housing 16 and the outer surface 32 of the second end wall 20. The PP layer 46 acts as an electrically insulating material and is configured to isolate components (such as electrode stacks) contained within the battery cell 14 from the housing 16. Similarly, the PET layer 48 is configured not only to electrically insulate the battery cell 14 but also to provide mechanical and chemical stability to the battery cell 14. In this configuration, the PET layer 48 is disposed between the housing 16 and the anisotropic material layer 44a.

[0118] In some examples, the prismatic battery assembly includes a first anisotropic material layer disposed on the inner surface of the sidewalls and a second anisotropic material layer disposed on the inner surface of the second endwalls. The positioning of the anisotropic materials on the inner surface of the housing isolates the electrode stack and other components contained within the battery cell from the housing. As a result, the anisotropic material layers can be encapsulated within PP using PP-graphite-PP double-sided tape. For example, and particularly refer to… Figures 4A-4EThe prismatic battery assembly 12b includes a first anisotropic material layer and a second anisotropic material layer, which are contained within the boundaries of the battery cell interior and the housing. Given that the components associated with the prismatic battery assembly 12 are substantially similar in structure and function, similar reference numerals are used below and in the accompanying drawings to identify similar components, while similar reference numerals including alphanumeric extensions are used to identify those modified components.

[0119] The prismatic battery assembly 12b includes a housing 16 formed of steel or a steel alloy, and the housing includes a first end wall and a second end wall 20 opposite to the first end wall. The housing 16 also includes one or more side walls 22 extending between the first end wall and the second end wall 20. The first end wall of the housing 16 includes an inner surface and an outer surface opposite to the inner surface. The inner surface of the first end wall is abuttable to the electrode stack of the battery cell 14, while the outer surface of the first end wall faces the outside of the battery cell 14. Similarly, the second end wall 20 of the housing 16 includes an inner surface 30 and an outer surface 32 opposite to the inner surface 30. The inner surface 30 of the second end wall 20 abuts to the battery cell 14, while the outer surface 32 of the second end wall 20 faces the outside of the battery cell 14. In a similar manner, the side wall 22 includes an inner surface 34 and an outer surface 36 opposite to the inner surface 34. The inner surface 34 of the side wall 22 abuts to the electrode stack of the battery cell 14, while the outer surface 36 of the side wall 22 faces the outside of the battery cell 14.

[0120] A thermal interface material (TIM) 38 is disposed below the battery cell 14 of the prismatic battery assembly 12b and thermally connects the battery cell 14 to a heat dissipation element or cold plate 40 for regulating the temperature of the prismatic battery assembly 12b. For example, the TIM 38 may abut against the outer surface 32 of the second end wall 20 of the battery cell 14 and be disposed between the cold plate 40 and the battery cell 14. The TIM 38 and the cold plate 40 may cooperate to act as a heat sink or heat diffuser to achieve efficient heat transfer from the battery cell 14 during operation.

[0121] A thermal runaway barrier (TRB) 42 is disposed between the outer surface 36 of the sidewall 22 of the housing 16 and the adjacent battery cell 14. In other words, the TRB 42 acts as a barrier between each battery cell 14 to limit thermal transfer between the battery cells 14. In this respect, the TRB 42 helps to reduce the potential for thermal runaway events to propagate between the battery cells 14 of the prismatic battery assembly 12b.

[0122] The prismatic battery assembly 12b includes a first anisotropic material layer 44b disposed on the inner surface 34 of the sidewall 22 and extending in a direction parallel to the sidewall 22. Furthermore, a second anisotropic material layer 58b is disposed on the inner surface 30 of the second end wall 20 and extends in a direction parallel to the second end wall 20. The anisotropic material layers 44b and 58b comprise graphite and are configured to dissipate heat generated within the battery cells 14. For example, heat generated within the housing 16 is at least partially dissipated into the first anisotropic material layer 44b and through the sidewall 22. Additionally, heat generated within the housing 16 is at least partially dissipated into the second anisotropic material layer 58b and through the second end wall 20. The second anisotropic material layer 58b may extend beneath one or more of the battery cells 14 of the prismatic battery assembly 12b to uniformly distribute the heat generated by the battery cells 14 across the TIM 38.

[0123] The first anisotropic material layer 44b is configured to allow a first-stage heat transfer along a direction parallel to the first anisotropic material layer 44b along the sidewall 22 and to allow a second-stage heat transfer along a direction transverse to the first anisotropic material layer 44b along the sidewall 22. In other words, the first anisotropic material layer 44b directs heat along the sidewall 22 toward the TIM 38 and the cold plate 40 for further dissipation from the battery cell 14, and the first anisotropic material layer 44b resists heat transfer from the sidewall 22 of the housing 16 toward the adjacent battery cell 14.

[0124] Additionally, the second anisotropic material layer 58b is configured to allow a third-level heat transfer along a direction parallel to the second anisotropic material layer 58b along the second end wall 20 and a fourth-level heat transfer along a direction transverse to the second anisotropic material layer 58b along the second end wall 20. In other words, the second anisotropic material layer 58b guides heat along the second end wall 20 and along the TIM 38 and cold plate 40 for further dissipation from the battery cell 14. Although the third-level heat transfer is greater than the fourth-level heat transfer, the adjacency of the second anisotropic material layer 58b with the large surface area of ​​the TIM 38 provides space for sufficient heat transfer through the second anisotropic material layer 58b into the TIM 38. In other words, heat diffuses rapidly during the third-level heat transfer to diffuse heat across the large surface area of ​​the TIM 38 and achieve sufficient heat transfer through the second end wall 20 into the TIM 38.

[0125] In other words, the first anisotropic material layer 44b has a first thermal conductivity level 50b extending in a direction parallel to the sidewall 22. Additionally, the first anisotropic material layer 44b has a second thermal conductivity level 52b extending in a direction transverse to the sidewall 22. (See reference...) Figure 3A and Figure 3BThe first thermal conductivity level 50b is indicated by an arrow pointing in a direction parallel to the sidewall 22, and the second thermal conductivity level 52b is indicated by an arrow pointing in a direction perpendicular to the sidewall 22. In other examples, the first anisotropic material layer 44b may, to varying degrees, resist and guide heat transfer relative to the wall of the housing 16 in any suitable direction. In the illustrated example, the first thermal conductivity level 50b is greater than the second thermal conductivity level 52b. In other words, heat transfer along the direction parallel to the sidewall 22 occurs more efficiently and faster than in the direction transverse to the sidewall 22. For example, the first thermal conductivity level 50b may be at or near 1800 watts / meter-Kelvin (W / mK), while the second thermal conductivity level 52b may be at or near 15 W / mK.

[0126] The second anisotropic material layer 58b has a third thermal conductivity level 54b extending in a direction parallel to the second end wall 20. Additionally, the second anisotropic material layer 58b has a fourth thermal conductivity level 56b extending in a direction transverse to the second end wall 20. The third thermal conductivity level 54b is indicated by an arrow pointing in a direction parallel to the second end wall 20, and the fourth thermal conductivity level 56b is indicated by an arrow pointing perpendicular to the second end wall 20. In other examples, the second anisotropic material layer 58b may resist and guide heat transfer relative to the wall of the housing 16 in any suitable direction to varying degrees. In the illustrated example, the third thermal conductivity level 54b is greater than the fourth thermal conductivity level 56b. In other words, heat transfer in a direction parallel to the second end wall 20 occurs more efficiently and faster than in a direction transverse to the second end wall 20. However, heat diffuses rapidly across the large surface area of ​​the TIM 38, thus achieving sufficient heat transfer along the second anisotropic material layer 58b and into the TIM 38. The third thermal conductivity level 54b can be at or near 1800 W / mK, while the fourth thermal conductivity level 56b can be at or near 15 W / mK.

[0127] During operation of the prismatic battery assembly 12b, heat generated within the battery cell 14 is transferred through the first anisotropic material layer 44b and the second anisotropic material layer 58b, ultimately reaching the sidewall 22 and the second end wall. A first thermal conductivity level 50b enables rapid and efficient heat transfer from the first end wall of the housing 16 toward the second end wall 20 of the housing 16 via the first anisotropic material layer 44b in a direction parallel to the sidewall 22. A second thermal conductivity level 52b inhibits heat transfer via the first anisotropic material layer 44b in a direction transverse to the sidewall 22. Furthermore, a third thermal conductivity level 54b enables rapid and efficient heat transfer via the second anisotropic material layer 58b in a direction parallel to the second end wall 20. A fourth thermal conductivity level 56b inhibits heat transfer via the second anisotropic material layer 58b in a direction transverse to the second end wall 20. However, heat can diffuse across the large surface area of ​​the TIM 38 to transfer into the TIM 38. In this respect, heat can travel through the first anisotropic material layer 44b and the second anisotropic material layer 58b, exiting from the casing 16 of the battery cell 14 and proceeding towards the TIM 38 and the cold plate 40. Due to the second thermal conductivity level 52b being significantly lower than the first thermal conductivity level 50b, heat transfer through the first anisotropic material layer 44b in the direction transverse to the sidewall 22 is resisted. In this respect, heat is generally prevented from traveling into the TRB 42, as the vast majority of the generated heat travels into the TIM 38 and the cold plate 40.

[0128] The first anisotropic material layer 44b allows the prismatic battery assembly 12b with a thin steel casing 16 to operate at temperatures similar to those experienced by batteries with typically thicker aluminum casings. For example, and as... Figure 4C-4E As shown, at position 300, the prismatic battery assembly 12b having battery cell 14 (with a steel casing 16 having a thickness of about 0.3 mm and anisotropic material layers 44b, 58b having a thickness of about 0.05 mm) can operate at about 48 degrees Celsius at the end of the battery life cycle. At position 302, the prismatic battery assembly 12b having battery cell 14 (with a steel casing 16 having a thickness of about 0.3 mm and anisotropic material layers 44b, 58b having a thickness of about 0.1 mm) can operate at about 47.7 degrees Celsius at the end of the battery life cycle. Generally, at position 304, the maximum operating temperature of battery cell 14 decreases with increasing thickness of anisotropic material layers 44b, 58b, and eventually stabilizes when the thickness of anisotropic material layers 44b, 58b is greater than about 0.075 mm. Furthermore, the maximum operating temperature of battery cell 14 is higher at the end of the battery life cycle compared to the beginning of the battery life cycle.

[0129] Furthermore, the prismatic battery assembly 12b includes a polypropylene (PP) layer 46 and a polyethylene terephthalate (PET) layer 48. The PP layer 46 is disposed on the inner surface 34 of the sidewall 22 of the housing 16 and the inner surface 30 of the second end wall 20. The PET layer 48 is disposed on the outer surface 36 of the sidewall 22 of the housing 16 and the outer surface 32 of the second end wall 20. The PP layer 46 acts as an electrically insulating material and is configured to isolate components (such as electrode stacks) contained within the battery cell 14 from the housing 16. Similarly, the PET layer 48 is configured not only to electrically insulate the battery cell 14 but also to provide mechanical and chemical stability to the battery cell 14. In this configuration, the PP layer 46 encapsulates anisotropic material layers 44b and 58b.

[0130] refer to Figure 4F At 400°C, the highest operating temperature of the battery cell 14 varies based on the configuration of the prismatic battery modules 12, 12a, and 12b, and specifically based on the configuration of the anisotropic material layers 44, 44a, 58a, 44b, and 58b. With increasing thickness of the anisotropic material layers 44, 44b, and 58b, the prismatic battery module 12 typically has the highest operating temperature of the battery cell 14 compared to the prismatic battery module 12b. Additionally, with increasing thickness of the anisotropic material layers 44a, 58a, 44b, and 58b, the prismatic battery module 12b typically has the highest operating temperature of the battery cell 14 compared to the prismatic battery module 12a.

[0131] In some examples, the prismatic battery assembly includes a first anisotropic material layer having a first roughness level and a second anisotropic material layer having a second roughness level. The first roughness level is greater than the second roughness level, and in this respect, heat transfer through the second anisotropic material layer can occur more efficiently and effectively than heat transfer through the first anisotropic material layer. For example, and particularly referring to... Figure 5 The prismatic battery assembly 12c includes a first anisotropic material layer having a first roughness level and a second anisotropic material layer having a second roughness level. Given that the components associated with the prismatic battery assembly 12 are substantially similar in structure and function, similar reference numerals are used below and in the accompanying drawings to identify similar components, while similar reference numerals including alphanumeric extensions are used to identify those modified components.

[0132] The prismatic battery assembly 12c includes a housing 16 formed of steel or a steel alloy, and the housing includes a first end wall and a second end wall 20 opposite to the first end wall. The housing 16 also includes one or more side walls 22 extending between the first end wall and the second end wall 20. The first end wall of the housing 16 includes an inner surface and an outer surface opposite to the inner surface. The inner surface of the first end wall is abuttable to the electrode stack of the battery cell 14, while the outer surface of the first end wall faces the outside of the battery cell 14. Similarly, the second end wall 20 of the housing 16 includes an inner surface 30 and an outer surface 32 opposite to the inner surface 30. The inner surface 30 of the second end wall 20 abuts to the battery cell 14, while the outer surface 32 of the second end wall 20 faces the outside of the battery cell 14. In a similar manner, the side wall 22 includes an inner surface 34 and an outer surface 36 opposite to the inner surface 34. The inner surface 34 of the side wall 22 abuts to the electrode stack of the battery cell 14, while the outer surface 36 of the side wall 22 faces the outside of the battery cell 14.

[0133] A thermal interface material (TIM) is disposed below the battery cell 14 of the prismatic battery assembly 12c and thermally connects the battery cell 14 to a heat dissipation element or cold plate for regulating the temperature of the prismatic battery assembly 12c. For example, the TIM may abut against the outer surface 32 of the second end wall 20 of the battery cell 14 and be disposed between the cold plate 40 and the battery cell 14. The TIM and the cold plate may cooperate to act as a heat sink or heat diffuser to achieve efficient heat transfer from the battery cell 14 during operation.

[0134] A thermal runaway barrier (TRB) is disposed between the outer surface 36 of the sidewall 22 of the housing 16 and the adjacent battery cells 14. In other words, the TRB acts as a barrier between each battery cell 14 to limit thermal transfer between the battery cells 14. In this respect, the TRB helps to reduce the potential for thermal runaway events to propagate between the battery cells 14 of the prismatic battery assembly 12c.

[0135] The prismatic battery assembly 12c includes a first anisotropic material layer 44c disposed on the outer surface 36 of the sidewall 22 and extending in a direction parallel to the sidewall 22. Furthermore, a second anisotropic material layer 58c is disposed on the outer surface 32 of the second end wall 20 and extends in a direction parallel to the second end wall 20. In other words, the first anisotropic material layer 44c is positioned between the outer surface 36 of the sidewall 22 and the TRB, and the second anisotropic material layer 58c is positioned between the outer surface 32 of the second end wall 20 and the TIM. The anisotropic material layers 44c and 58c comprise graphite and are configured to dissipate heat generated within the battery cell 14. For example, heat generated within the housing 16 is at least partially dissipated through the sidewall 22 and into the first anisotropic material layer 44c. Additionally, heat generated within the housing 16 is at least partially dissipated through the second end wall 20 and into the second anisotropic material layer 58c. The second anisotropic material layer 58c may extend beneath one or more of the battery cells 14 of the prismatic battery assembly 12c to uniformly distribute the heat generated by the battery cells 14 across the TIM.

[0136] The first anisotropic material layer 44c has a first surface roughness, while the second anisotropic material layer 58c has a second surface roughness. The first surface roughness is greater than the second surface roughness, as indicated by the difference in thermal conductivity. In this respect, the thermal conductivity is lower on a rougher surface compared to that on a smoother surface. As a result, heat transfer through the second anisotropic material layer 58c can occur more efficiently than heat transfer through the first anisotropic material layer 44c. This directs heat transfer to occur closest to the TIM and furthest from the TRB.

[0137] The first anisotropic material layer 44c is configured to allow a first-stage heat transfer along a direction parallel to the first anisotropic material layer 44c along the sidewall 22 and to allow a second-stage heat transfer along a direction transverse to the first anisotropic material layer 44c along the sidewall 22. In other words, the first anisotropic material layer 44c directs heat along the sidewall 22 toward the TIM and the cold plate for further dissipation from the battery cell 14, and the first anisotropic material layer 44a resists heat transfer from the sidewall 22 of the housing 16 toward the adjacent battery cell 14.

[0138] Additionally, the second anisotropic material layer 58c is configured to allow a third-level heat transfer along a direction parallel to the second anisotropic material layer 58c along the second end wall 20 and a fourth-level heat transfer along a direction transverse to the second anisotropic material layer 58c along the second end wall 20. In other words, the second anisotropic material layer 58c guides heat along the second end wall 20 and along the TIM and cold plate for further dissipation from the battery cell 14. Although the third-level heat transfer is greater than the fourth-level heat transfer, the positioning of the second anisotropic material layer 58c against the large surface area of ​​the TIM provides space for sufficient heat transfer into the TIM through the second anisotropic material layer 58c. In other words, heat diffuses rapidly during the third-level heat transfer to diffuse heat across the large surface area of ​​the TIM and achieve sufficient heat transfer into the TIM. Additionally, the third-level heat transfer is greater than the first-level heat transfer, and the fourth-level heat transfer is greater than the second-level heat transfer. This is because the first surface roughness of the first anisotropic material layer 44c is greater than the second surface roughness of the second anisotropic material layer 58c.

[0139] In other words, the first anisotropic material layer 44c has a first thermal conductivity level 50c extending in a direction parallel to the sidewall 22. Additionally, the first anisotropic material layer 44c has a second thermal conductivity level 52c extending in a direction transverse to the sidewall 22. (See reference...) Figure 5 The first thermal conductivity level 50c is indicated by an arrow pointing in a direction parallel to the sidewall 22, and the second thermal conductivity level 52c is indicated by an arrow pointing in a direction perpendicular to the sidewall 22. In other examples, the first anisotropic material layer 44c may, to varying degrees, resist and guide heat transfer relative to the wall of the housing 16 in any suitable direction. In the illustrated example, the first thermal conductivity level 50c is greater than the second thermal conductivity level 52c. In other words, heat transfer along the direction parallel to the sidewall 22 occurs more efficiently and faster than in the direction transverse to the sidewall 22.

[0140] The second anisotropic material layer 58c has a third thermal conductivity level 54c extending in a direction parallel to the second end wall 20. Additionally, the second anisotropic material layer 58c has a fourth thermal conductivity level 56c extending in a direction transverse to the second end wall 20. The third thermal conductivity level 54c is indicated by an arrow pointing in a direction parallel to the second end wall 20, and the fourth thermal conductivity level 56c is indicated by an arrow pointing perpendicular to the second end wall 20. In other examples, the second anisotropic material layer 58c may resist and guide heat transfer relative to the wall of the housing 16 in any suitable direction to varying degrees. In the illustrated example, the third thermal conductivity level 54c is greater than the fourth thermal conductivity level 56c. In other words, heat transfer in a direction parallel to the second end wall 20 occurs more efficiently and faster than in a direction transverse to the second end wall 20. However, heat diffuses rapidly across the large surface area of ​​the TIM, thus achieving sufficient heat transfer along the second anisotropic material layer 58c and into the TIM. The third thermal conductivity level of 54c is greater than the first thermal conductivity level of 50c, while the fourth thermal conductivity level of 56c is greater than the second thermal conductivity level of 52c.

[0141] During operation of the prismatic battery assembly 12c, heat generated within the battery cell 14 is transferred via the sidewalls 22 and the second endwall 20, ultimately reaching the first anisotropic material layer 44c. A first thermal conductivity level 50c enables rapid and efficient heat transfer from the first endwall of the housing 16 toward the second endwall 20 of the housing 16 through the first anisotropic material layer 44c in a direction parallel to the sidewalls 22. A second thermal conductivity level 52c inhibits heat transfer through the first anisotropic material layer 44c in a direction transverse to the sidewalls 22. Furthermore, a third thermal conductivity level 54c enables rapid and efficient heat transfer through the second anisotropic material layer 58c in a direction parallel to the second endwall 20. A fourth thermal conductivity level 56c inhibits heat transfer through the second anisotropic material layer 58c in a direction transverse to the second endwall 20. However, heat can diffuse across the large surface area of ​​the TIM to transfer into the TIM. In this respect, heat can travel from the battery cell 14 into the anisotropic material layers 44c and 58c, and towards the TIM and the cold plate. Due to the fact that the second thermal conductivity level 52c is much lower than the first thermal conductivity level 50c, heat transfer through the first anisotropic material layer 44a in the direction transverse to the sidewall 22 is resisted. In this respect, heat is generally prevented from traveling into the TRB, as the vast majority of the generated heat travels into the TIM and the cold plate.

[0142] Furthermore, the prismatic battery assembly 12c includes a polypropylene (PP) layer 46 and a polyethylene terephthalate (PET) layer 48. The PP layer 46 is disposed on the inner surface 34 of the sidewall 22 of the housing 16 and the inner surface 30 of the second end wall 20. The PET layer 48 is disposed on the outer surface 36 of the sidewall 22 of the housing 16 and the outer surface 32 of the second end wall 20. The PP layer 46 acts as an electrically insulating material and is configured to isolate components (such as electrode stacks) contained within the battery cell 14 from the housing 16. Similarly, the PET layer 48 is configured not only to electrically insulate the battery cell 14 but also to provide mechanical and chemical stability to the battery cell 14. In this configuration, the PET layer 48 is disposed between the housing 16 and the anisotropic material layers 44c and 58c.

[0143] In some examples, the prismatic battery assembly includes an anisotropic material layer disposed between the housing and the PET layer. For example, and specifically referring to... Figure 6 The prismatic battery assembly 12d includes a first anisotropic material layer disposed between the sidewalls and the PET layer, and a second anisotropic material layer disposed between the second endwalls and the PET layer. Given that the components associated with the prismatic battery assembly 12 are substantially similar in structure and function, similar reference numerals are used hereinafter and in the accompanying drawings to identify similar components, while similar reference numerals including alphanumeric extensions are used to identify modified components.

[0144] The prismatic battery assembly 12d includes a housing 16 formed of steel or a steel alloy, and the housing includes a first end wall and a second end wall 20 opposite to the first end wall. The housing 16 also includes one or more side walls 22 extending between the first end wall and the second end wall 20. The first end wall of the housing 16 includes an inner surface and an outer surface opposite to the inner surface. The inner surface of the first end wall is abuttable to the electrode stack of the battery cell 14, while the outer surface of the first end wall faces the outside of the battery cell 14. Similarly, the second end wall 20 of the housing 16 includes an inner surface 30 and an outer surface 32 opposite to the inner surface 30. The inner surface 30 of the second end wall 20 abuts to the battery cell 14, while the outer surface 32 of the second end wall 20 faces the outside of the battery cell 14. In a similar manner, the side wall 22 includes an inner surface 34 and an outer surface 36 opposite to the inner surface 34. The inner surface 34 of the side wall 22 abuts to the electrode stack of the battery cell 14, while the outer surface 36 of the side wall 22 faces the outside of the battery cell 14.

[0145] A thermal interface material (TIM) is disposed below the battery cell 14 of the prismatic battery assembly 12d and thermally connects the battery cell 14 to a heat dissipation element or cold plate for regulating the temperature of the prismatic battery assembly 12d. For example, the TIM may abut against the outer surface 32 of the second end wall 20 of the battery cell 14 and be disposed between the cold plate and the battery cell 14. The TIM and the cold plate may cooperate to act as a heat sink or heat diffuser to achieve efficient heat transfer from the battery cell during operation of the battery cell 14.

[0146] A thermal runaway barrier (TRB) is disposed between the outer surface 36 of the sidewall 22 of the housing 16 and the adjacent battery cells 14. In other words, the TRB acts as a barrier between each battery cell 14 to limit thermal transfer between the battery cells 14. In this respect, the TRB helps to reduce the potential for thermal runaway events to propagate between the battery cells 14 of the prismatic battery assembly 12d.

[0147] The prismatic battery assembly 12d includes a first anisotropic material layer 44d disposed on the outer surface 36 of the sidewall 22 and extending in a direction parallel to the sidewall 22. Furthermore, a second anisotropic material layer 58d is disposed on the outer surface 32 of the second end wall 20 and extends in a direction parallel to the second end wall 20. In other words, the first anisotropic material layer 44d is positioned between the outer surface 36 of the sidewall 22 and the TRB, and the second anisotropic material layer 58d is positioned between the outer surface 32 of the second end wall 20 and the TIM. The anisotropic material layers 44d and 58d comprise graphite and are configured to dissipate heat generated within the battery cell 14. For example, heat generated within the housing 16 is at least partially dissipated through the sidewall 22 and into the first anisotropic material layer 44d. Additionally, heat generated within the housing 16 is at least partially dissipated through the second end wall 20 and into the second anisotropic material layer 58d. The second anisotropic material layer 58d may extend beneath one or more of the battery cells 14 of the prismatic battery assembly 12d to uniformly distribute the heat generated by the battery cells 14 across the TIM.

[0148] The first anisotropic material layer 44d is configured to allow a first-stage heat transfer along a direction parallel to the first anisotropic material layer 44d along the sidewall 22 and to allow a second-stage heat transfer along a direction transverse to the first anisotropic material layer 44d along the sidewall 22. In other words, the first anisotropic material layer 44d directs heat along the sidewall 22 toward the TIM and the cold plate for further dissipation from the battery cell 14, and the first anisotropic material layer 44d resists heat transfer from the sidewall 22 of the housing 16 toward the adjacent battery cell 14.

[0149] Additionally, the second anisotropic material layer 58d is configured to allow a third-level heat transfer along a direction parallel to the second anisotropic material layer 58d along the second end wall 20 and a fourth-level heat transfer along a direction transverse to the second anisotropic material layer 58d along the second end wall 20. In other words, the second anisotropic material layer 58d guides heat along the second end wall 20 and along the TIM and cold plate for further dissipation from the battery cell 14. Although the third-level heat transfer is greater than the fourth-level heat transfer, the positioning of the second anisotropic material layer 58d against the large surface area of ​​the TIM provides space for sufficient heat transfer into the TIM through the second anisotropic material layer 58d. In other words, heat diffuses rapidly during the third-level heat transfer to diffuse heat across the large surface area of ​​the TIM and achieve sufficient heat transfer into the TIM.

[0150] In other words, the first anisotropic material layer 44d has a first thermal conductivity level 50d extending in a direction parallel to the sidewall 22. Additionally, the first anisotropic material layer 44d has a second thermal conductivity level 52d extending in a direction transverse to the sidewall 22. (Reference) Figure 6 The first thermal conductivity level 50d is indicated by an arrow pointing parallel to the sidewall 22, and the second thermal conductivity level 52d is indicated by an arrow pointing perpendicular to the sidewall 22. In other examples, the first anisotropic material layer 44d may, to varying degrees, resist and guide heat transfer relative to the wall of the housing 16 in any suitable direction. In the illustrated example, the first thermal conductivity level 50d is greater than the second thermal conductivity level 52d. In other words, heat transfer along the direction parallel to the sidewall 22 occurs more efficiently and faster than in the direction transverse to the sidewall 22. For example, the first thermal conductivity level 50d may be at or near 1800 watts / meter-Kelvin (W / mK), while the second thermal conductivity level 52d may be at or near 15 W / mK.

[0151] The second anisotropic material layer 58d has a third thermal conductivity level 54d extending in a direction parallel to the second end wall 20. Additionally, the second anisotropic material layer 58d has a fourth thermal conductivity level 56d extending in a direction transverse to the second end wall 20. The third thermal conductivity level 54d is indicated by an arrow pointing in a direction parallel to the second end wall 20, and the fourth thermal conductivity level 56d is indicated by an arrow pointing perpendicular to the second end wall 20. In other examples, the second anisotropic material layer 58d may resist and guide heat transfer relative to the wall of the housing 16 in any suitable direction to varying degrees. In the illustrated example, the third thermal conductivity level 54d is greater than the fourth thermal conductivity level 56d. In other words, heat transfer in a direction parallel to the second end wall 20 occurs more efficiently and faster than in a direction transverse to the second end wall 20. However, heat diffuses rapidly across the large surface area of ​​the TIM, thus achieving sufficient heat transfer along the second anisotropic material layer 58d and into the TIM. The third thermal conductivity level, 54d, can be at or near 1800 W / mK, while the fourth thermal conductivity level, 56d, can be at or near 15 W / mK.

[0152] During operation of the prismatic battery assembly 12d, heat generated within the battery cell 14 is transferred through the sidewalls 22 and the second endwall 20 and ultimately reaches the first anisotropic material layer 44d. A first thermal conductivity level 50d enables rapid and efficient heat transfer from the first endwall of the housing 16 toward the second endwall 20 of the housing 16 via the first anisotropic material layer 44d in a direction parallel to the sidewalls 22. A second thermal conductivity level 52d inhibits heat transfer via the first anisotropic material layer 44d in a direction transverse to the sidewalls 22. Furthermore, a third thermal conductivity level 54d enables rapid and efficient heat transfer via the second anisotropic material layer 58d in a direction parallel to the second endwall 20. A fourth thermal conductivity level 56d inhibits heat transfer via the second anisotropic material layer 44d in a direction transverse to the second endwall 20. However, heat is allowed to travel out of the battery cell 14, into the anisotropic material layers 44d and 58d, and toward the TIM and the cold plate. Because the second thermal conductivity level 52d is much lower than the first thermal conductivity level 50d, heat transfer through the first anisotropic material layer 44d in the direction transverse to the sidewall 22 is inhibited. In this respect, heat is generally prevented from traveling into the TRB, as the vast majority of the generated heat travels into the TIM and the cold plate.

[0153] Furthermore, the prismatic battery assembly 12d includes a polyethylene terephthalate (PET) layer 48d. The PET layer 48d is disposed on the outer surface 36 of the sidewall 22 and the outer surface 32 of the second end wall 20 of the housing 16. The PET layer 48d is configured to not only electrically insulate the battery cell 14 but also provide mechanical and chemical stability to the battery cell 14. In this configuration, anisotropic material layers 44d and 58d are disposed between the housing 16 and the PET layer 48d.

[0154] Several embodiments have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of this disclosure. Therefore, other embodiments are within the scope of the following claims.

[0155] The foregoing description has been provided for illustrative and descriptive purposes. It is not intended to be exhaustive or limiting of this disclosure. Elements or features of a particular configuration are generally not limited to that particular configuration, but are interchangeable where applicable and can be used in a selected configuration (even if not specifically shown or described). The same configuration may also have various variations. These variations should not be considered a departure from this disclosure, and all such modifications should be included within the scope of this disclosure.

Claims

1. A prismatic battery assembly comprising: a battery cell comprising a housing having a first end, a second end, a sidewall extending between the first end and the second end, and a terminal disposed at the first end; a heat dissipation element extending along the second end; a layer of anisotropic material extending in a direction parallel to the sidewall, the anisotropic material having a first level of thermal conductivity in a direction parallel to the sidewall and a second level of thermal conductivity in a direction transverse to the sidewall, the first level of thermal conductivity being greater than the second level of thermal conductivity; and wherein, during operation of the prismatic battery assembly, heat generated within the housing of the battery cell is dissipated along the layer of anisotropic material in a direction parallel to the sidewall and into the heat dissipation element.

2. The prismatic battery assembly of claim 1, wherein, The layer of anisotropic material extends along an outer surface of the sidewall.

3. The prismatic battery assembly of claim 1, wherein, The layer of anisotropic material extends along an inner surface of the sidewall.

4. The prismatic battery assembly of claim 3, wherein, At least one layer of electrically insulating material extends along the layer of anisotropic material.

5. The prismatic battery assembly of claim 1, wherein, Another layer of anisotropic material extends along the second end of the housing.

6. The prismatic battery assembly of claim 5, wherein, The other layer of anisotropic material extends along an outer surface of the second end of the housing.

7. The prismatic battery assembly of claim 6, wherein, The layer of anisotropic material has a first surface roughness and the other layer of anisotropic material has a second surface roughness, the first surface roughness being greater than the second surface roughness.

8. The prismatic battery assembly of claim 5, wherein, The other layer of anisotropic material extends along an inner surface of the second end of the housing.

9. The prismatic battery assembly of claim 1, wherein, The layer of anisotropic material comprises a polyethylene terephthalate (PET) substrate.

10. The prismatic battery assembly of claim 1, wherein, The layer of anisotropic material comprises graphite.

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