Device for directing exhaust gas emissions in battery cells

Abstract

Disclosed is a device for directing exhaust gas discharge from a battery cell. A battery system is disclosed. The system includes a frame surrounding a battery active area and defining an exhaust port. The exhaust port is carried by the frame and mounted between the battery active area and a coolant channel. The exhaust port can be configured to discharge gas from the battery active area into the coolant channel in response to the pressure or temperature of gas exceeding a predetermined threshold, and otherwise isolate the battery active area from the coolant channel.

Description

Technical Field

[0001] The present invention relates to the field of batteries and battery modules. Background Art

[0002] Hybrid vehicles typically include a high-voltage battery pack suitable for providing power to various components of the vehicle, including the electric motor, transmission, and electrical accessories. The battery pack can be composed of a variety of chemistries such as lithium-ion, nickel metal hydride, or nickel cadmium. The battery pack can also include multiple battery cells connected in series, parallel, or a combination thereof. Each battery cell may include a cathode, an anode, and an electrolyte. The electrolyte is a medium that allows charge to flow between the cathode and anode. The electrochemical reactions that occur within the battery cells allow the battery pack to be used as an energy source.

[0003] The performance of the battery pack may deteriorate over time due to cell decomposition or abuse conditions (including but not limited to overcharge, internal short circuit, external short circuit and over-discharge, etc.). Decomposition or abuse conditions of the battery cell may trigger gas accumulation and subsequent pressure increase within the battery cell. The increase in pressure may occur relatively slowly due to the decomposition of the battery cell throughout the life of the battery cell. Alternatively, the increase in pressure may occur rapidly in response to an increase in temperature in the battery cell. Depending on the type of battery, battery cell venting may be characterized by the following items: the battery cell is pressurized, gases such as evaporated solvents are discharged from the battery cell, or electrolytes are discharged from the battery cell. Some batteries may include vents to accommodate pressure, gas release, or discharge of electrolytes from the battery cell. Summary of the Invention

[0004] According to one embodiment of the present disclosure, a battery system is disclosed. The system may include a frame surrounding a battery active area and defining a vent, the vent being carried by the frame and mounted between the battery active area and a coolant channel. The vent may be configured to discharge gas from the battery active area into the coolant channel in response to the pressure or temperature of gas exceeding a predetermined threshold, and otherwise isolate the battery active area from the coolant channel.

[0005] According to another embodiment of the present disclosure, a battery system is disclosed. The system may include a hollow frame surrounding a battery active area, a first flexible sheet, a second flexible sheet, and a first vent. The first and second flexible sheets may be attached to opposite sides of the hollow frame to encapsulate the battery active area. The first vent may be mounted to the hollow frame and configured to discharge gas from the battery active area into the interior of the hollow frame in response to the temperature or pressure of gas exceeding a first predetermined threshold.

[0006] According to one embodiment of the present disclosure, the system further includes a second exhaust port mounted to the hollow frame, wherein the second exhaust port is configured to exhaust the gas from inside the hollow frame in response to the temperature or pressure of the gas from inside the hollow frame exceeding a second predetermined threshold.

[0007] According to one embodiment of the present disclosure, the first predetermined threshold and the second predetermined threshold are proportional to each other.

[0008] According to one embodiment of the present disclosure, the hollow frame is configured to guide a coolant therethrough.

[0009] According to another embodiment of the present disclosure, a battery system is disclosed. The system may include a hollow frame surrounding an active area of ​​a battery, a first exhaust port, and a gas adsorbent material contained within the hollow frame. The first exhaust port may be carried by the hollow frame and may be configured to discharge gas from the active area of ​​the battery to the gas adsorbent material contained within the hollow frame in response to the temperature or pressure of gas exceeding a first predetermined threshold.

[0010] According to one embodiment of the present disclosure, the gas adsorbent material is vermiculite.

[0011] According to one embodiment of the present disclosure, the first exhaust port is a one-way pressure valve or a temperature-sensitive burst disk. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 is an exploded view of a battery cell according to one embodiment of the present disclosure.

[0013] Figure 1A It is along Figure 1 A cross-sectional view taken along line 1A in FIG.

[0014] Figure 2 is an exploded view of an exemplary battery cell according to another embodiment of the present disclosure. DETAILED DESCRIPTION

[0015] Various embodiments of the present disclosure are described herein. However, the disclosed embodiments are merely exemplary, and other embodiments may take various alternative forms not expressly shown or described. The figures are not necessarily drawn to scale; some features may be exaggerated or minimized to show details of particular components. Therefore, the specific structural and functional details disclosed herein should not be construed as limiting, but merely as a representative basis for teaching one of ordinary skill in the art to utilize the invention in various ways. It will be understood by one of ordinary skill in the art that the various features shown and described with reference to any one of the figures may be combined with features shown in one or more of the other figures to produce embodiments not expressly shown or described. The combinations of features shown provide representative embodiments for typical applications. However, various combinations and variations of features consistent with the teachings of the present disclosure may be desired for particular applications or implementations.

[0016] Except where expressly indicated otherwise, all quantitative values ​​in this specification indicating dimensions or material properties are to be understood as modified by the term "about," which describes the broadest scope of the present disclosure.

[0017] The first definition of an acronym or other abbreviation applies to all subsequent uses of the same abbreviation herein, and mutatis mutandis, to normal grammatical variations of the initially defined abbreviation. Unless expressly stated to the contrary, measurements of a property are determined by the same techniques as those previously or subsequently cited for the same property.

[0018] A description of a group or class of materials suitable for a given purpose related to one or more embodiments of the present invention implies that mixtures of any two or more of the components of the group or class are also suitable. The description of ingredients in chemical terms refers to the ingredients when added to any combination specified in the description, and does not necessarily exclude chemical reactions between the ingredients of the mixture once mixed. With the mass production of batteries, a variety of battery forms have been developed. Example battery forms include cylindrical battery cells, button battery cells, prismatic battery cells, frame battery cells and pouch battery cells. The design of pouch battery cells is characterized by efficient use of space and achieves a packaging efficiency of approximately 90%-95%. Instead of using a metal cylinder and a glass-metal electrical feed-through, the conductive foil tabs are typically welded to the electrodes while extending to the outside of the pouch and are completely sealed. By removing the metal casing, the weight of the pouch battery cell is reduced. The frame battery cell may include a rigid plastic frame and a packaging frame or a flexible polymer sheet adhered to the top and bottom surfaces of the frame.

[0019] While pouch cells are a lightweight solution for battery design, there are many considerations with the pouch form, such as support requirements and space for expansion. An additional consideration is exposure to moisture and high temperature environments, which can shorten the life of the battery cell. Swelling represents another consideration; for example, expansion of 8%-10% may be common for some types of pouch cells after 500 cycles. However, pouch cells have become popular, especially when held to the same performance standards as cylindrical cells. Pouch cells have been successfully used in consumer applications, military applications, and vehicle applications. Relatively large, flat packs of pouch cells have been used in electric powertrains and energy storage systems. Relatively small pouch cells have been used in portable applications with high load current requirements.

[0020] The battery cells may be encapsulated or surrounded by a pouch or rigid frame. As the battery cells of a battery begin to decompose or degrade, gases generated in the active areas may cause a buildup of pressure. Pouch-type battery cells or frame-type battery cells may not typically include dedicated gas vents capable of releasing gases formed by the reaction between the electrolyte solvent and the active material. Pouch-type battery cells are typically confined between pressure plates to ensure that the increase in internal pressure caused by gas generation exerts maximum pressure on the seams and promotes the release of controlled gases under fault conditions. However, experience from battery cell testing has shown that the location and distribution of gas release may not occur in a predictable manner at consistent pressures or locations. It would be advantageous to develop a secondary containment structure that is capable of venting gases in a predictable manner and location. In addition, it may be advantageous to provide a gas adsorbent material within a portion of the battery cell or to incorporate a venting mechanism into the battery cooling device for the battery cell.

[0021] Reference Figure 1 , showing an exploded view of a battery cell 40. The battery cell 40 includes an outer bag 12 or outer sheet 12 surrounding a frame 42 or adhered to the frame 42. The frame 42 may be made of a rigid plastic material including a thermoplastic, a thermosetting plastic or a polymer. Alternatively, the frame may be made of a fiber-reinforced material. Fiber-reinforced plastics (also known as fiber-reinforced polymers) are composite materials made of a polymer matrix reinforced with fibers. The fibers may be glass, carbon, basalt, aramid or other suitable reinforcing materials. The polymer may be an epoxy resin, vinyl ester, polyester thermosetting plastic, phenolic resin or other suitable polymer or plastic. The fiber-reinforced plastic may also be cured by heating and / or pressurizing.

[0022] Although the frame 42 shown is rectangular, it can have other suitable shapes. The frame 42 defines an internal opening (aperture) 43 and two electrodes (not shown) of the battery cell 40, and the internal opening 43 surrounds the active area 16. The term battery active area 16 can include anodes, cathodes, electrolytes, and separator layers in an organized structure (wound, z-folded, stacked, etc.) connected to corresponding external electrode terminals 14. The battery terminals 14 extend through the external bag 12 from the opening 43 of the frame 42. The external bag 12 includes a first sheet at the top of the drawing page and a second sheet at the bottom of the drawing page. Each sheet includes four outer edges 12a, 12b, 12c, and 12d aligned with the four outer edges 42a, 42b, 42c, and 42d of the frame 42. The first and second sheets of the external bag 12 can be heat-sealed to the frame 42 along the edges 42a, 42b, 42c, and 42d. Edges 42a, 42b, 42c, and 42d or edges 12a, 12b, 12c, and 12d or edges 42a, 42b, 42c, 42d, 12a, 12b, 12c, and 12d may include a heat-activated adhesive or other suitable material for sealing. In other embodiments, the edges may be sealed by induction sealing, induction welding, ultrasonic welding, or other suitable sealing or fastening means.

[0023] The frame 42 includes at least one vent 22 in one or more portions of the frame defining an opening 43. The vent 22 may be disposed within or secured to the inner periphery of the frame member 42. The vent 22 may also be disposed within an outer portion of the frame 42 (as shown on the left side of the drawing). In other embodiments, the frame 42 may define a hole or opening (not shown) that is smaller than the vent 22. In this case, the vent may be disposed above the opening so that it is adhered or connected to the area surrounding the hole or opening. The vent 22 may be a pressure-sensitive burst seal that allows gas from the opening 43 to escape through the seal 22 once the pressure within the opening 43 defined by the frame 42 exceeds a predetermined pressure. The pressure-sensitive burst seal may be attached to the inner bag using an adhesive or other suitable means. In one or more embodiments, the burst seal may include a perforated portion designed to burst at a predetermined pressure. Alternatively, the seal may be a valve such as a check valve, a flap valve, a non-return valve, or a one-way valve. In one or more embodiments, the vent 22 can be a temperature-sensitive burst seal. The temperature-sensitive burst seal can rupture or burst when the temperature within the opening 43 or frame 42 reaches a predetermined temperature. In other embodiments, the vent can be a burst seal that is both temperature-sensitive and pressure-sensitive.

[0024] If the vent 22 releases gas from the opening 43 to the outer bag 12, the gas will then be exhausted by the cavity 44 ( Figure 1A ) is captured. The exhaust device can be designed to exhaust or release gas at a predetermined rate to prevent pressure from building up too quickly within the opening 43. Alternatively, the exhaust device can allow gas from the opening 43 to be quickly released into the cavity 44 defined by the frame 42. Once the pressure or temperature within the opening 43 and the cavity 44 are the same, the exhaust device 22 can prevent gas from the opening 43 from flowing into the cavity 44 defined by the frame 42. As will be described in more detail below, the exhaust device 22 can be placed within or on or both of the holes or openings on the inner or outer periphery of the frame 42.

[0025] The frame may be hollow and define an interior space or cavity 44 ( Figure 1A ). The exhaust device arranged within the inner periphery of the frame 42 allows the gas generated by the active area 16 to enter the cavity 44. The cavity 44 may include a gas adsorbent material or a gas collection material (not shown). The gas adsorbent material or gas collection material may be arranged within the cavity defined by the frame, covering the entire cavity or only in a portion of the cavity. The gas adsorbent material or gas collection material may include vermiculite, metal-organic frameworks (MOF), activated carbon or other suitable materials. The material may be homogeneous or a combination of the materials just described. The second exhaust device 22' may also be arranged on the outer periphery or a portion of the frame 42. The second exhaust device 22' may release or allow the gas in the cavity 44 of the frame 42 to the external area surrounding the frame 42. The second exhaust device 22' may be arranged near a duct or an area of ​​the vehicle to guide the gas from the battery cell away towards the ground to prevent gas accumulation. If more than one exhaust device 22 is used, they are respectively configured to allow proportional exhaust. For example, exhaust 22 may have a threshold that is greater or lesser than the threshold defined by second exhaust 22 ′.

[0026] Reference Figure 2 , shows an exploded view of a battery cell 100 according to another embodiment. The battery cell 100 is substantially similar to the battery cell 40 described above. However, the battery cell 100 here incorporates a battery coolant system within the frame 42. The coolant system includes a coolant inlet 102 and a coolant outlet 104. A coolant channel 106 may extend between the coolant inlet 102 and the coolant outlet 104. The coolant channel 106 may be integrally formed with the frame (similar to Figure 1AThe coolant channel 106 may be a single channel or line inserted into the cavity 44 of the frame. The one or more coolant channels may be arranged along the periphery of the frame 42. In other embodiments, the channel 106 may be bifurcated to include two branches. The fluid may be a coolant such as air, oxygen, water, or other liquid coolant. Optionally, the fluid may provide heat to the battery cells 100. Optionally, the channel 106 may be used for both heating and cooling.

[0027] To regulate the temperature of the battery cells 100, a coolant may be pumped or delivered through a coolant inlet 102 extending through the frame 42 before terminating at a coolant outlet 104. The coolant may be a fluid material or a gaseous material, such as air, oxygen, water, or some mixture thereof. Optionally, the fluid may provide heat to the battery cells 100. Optionally, the coolant system may be used for both heating and cooling. As previously described, the exhaust device 22 may be disposed within a portion of the frame defining the opening 43. The exhaust device 22 exhausts gas into the coolant channel so that the gas is then transported by the coolant flowing through the coolant channel or cavity until the coolant and gas mixture is exhausted from the frame and opening 43.

[0028] The words used in the specification are descriptive and not restrictive, and it should be understood that various changes can be made without departing from the spirit and scope of the present disclosure and claims. As previously mentioned, the features of the various embodiments can be combined to form further embodiments that may not be explicitly described or illustrated. Although various embodiments may have been described as providing advantages or being superior to other embodiments or prior art implementations in terms of one or more desired characteristics, it should be recognized by those of ordinary skill in the art that, depending on the specific application and implementation, one or more features or characteristics may be compromised in order to achieve the desired overall system properties. These properties include, but are not limited to, cost, strength, durability, life cycle cost, marketability, appearance, packaging, size, maintainability, weight, manufacturability, ease of assembly, etc. Therefore, embodiments described as being less desirable than other embodiments or prior art implementations in one or more characteristics are not outside the scope of the present disclosure and can be expected to be used in specific applications.

Claims

1. A battery system comprising: a frame surrounding the battery active area and defining coolant channels; an inlet extending from the first portion of the frame and terminating in the coolant passage; an outlet extending from the second portion of the frame and terminating in the coolant passage; as well as a vent carried by the frame and mounted between the battery active area and the coolant channel and configured to: vent gas from the battery active area to the coolant channel in response to a pressure or temperature of the gas from the battery active area exceeding a predetermined threshold, and otherwise isolate the battery active area from the coolant channel, The inlet, coolant passage, and outlet are arranged such that coolant received from the inlet carries the exhausted gas through the coolant passage to the outlet.

2. The battery system according to claim 1, wherein: The exhaust port is a one-way pressure valve.

3. The battery system according to claim 1, wherein: The exhaust port is a temperature sensitive bursting disk. 4 . The battery system of claim 1 , further comprising first and second flexible sheets attached to opposing surfaces of the frame to encapsulate a battery active area.

5. The battery system according to claim 1, wherein: The coolant channels are configured to direct coolant around the perimeter of the battery active area to draw heat away from the battery active area.

6. A battery system comprising a plurality of battery cells, each battery cell comprising: a hollow frame surrounding the active area of ​​the battery, wherein the inner periphery of the hollow frame defines a vent; a first flexible sheet and a second flexible sheet attached to opposite sides of the hollow frame to define an encapsulation space for the battery active area by the hollow frame, the first flexible sheet, and the second flexible sheet; as well as The first exhaust device is installed in or on the exhaust hole on the inner periphery of the hollow frame and is configured to allow the gas in the packaging space to be discharged to the interior of the hollow frame through the exhaust hole in response to the temperature or pressure of the gas from the battery active area exceeding a first predetermined threshold.

7. The battery system according to claim 6, wherein: The first venting device is a pressure sensitive burst seal. 8 . The battery system according to claim 6 , further comprising a gas adsorbent material disposed within the hollow frame.

9. The battery system according to claim 8, wherein: The gas adsorbent material is vermiculite.

10. The battery system according to claim 8, further comprising a second exhaust device mounted to the hollow frame, the second exhaust device being configured to exhaust the gas from the inside of the hollow frame in response to the temperature or pressure of the gas from the inside of the hollow frame exceeding a second predetermined threshold.

11. The battery system according to claim 10, wherein: A second exhaust device is mounted to an outer periphery of the hollow frame.

12. The battery system according to claim 8, wherein: The first exhaust device is a one-way pressure valve or a temperature-sensitive bursting disk.

13. A battery system comprising a plurality of battery cells, each battery cell comprising: a hollow frame surrounding the battery active area and defining vents; a gas adsorbent material contained by the hollow frame; an outer bag surrounding the hollow frame to encapsulate the battery active area and the hollow frame; as well as The first venting device is installed in or on the vent hole and is configured to allow the gas in the outer bag to be discharged to the interior of the hollow frame to be adsorbed by the gas adsorbent material contained by the hollow frame in response to the temperature or pressure of the gas from the battery active area exceeding a first predetermined threshold.

14. The battery system according to claim 13, further comprising: The second exhaust device is carried by the hollow frame and is configured to exhaust the gas from the hollow frame.

15. The battery system according to claim 14, wherein: An exhaust hole is defined at an inner periphery of the hollow frame, a first exhaust device is mounted to the inner periphery of the hollow frame, and a second exhaust device is mounted to the outer periphery of the hollow frame.

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