Battery cell design with resealable pressure relief valve

Abstract

The invention relates to a battery cell design with a resealable pressure relief valve. A battery cell includes a cell housing and an electrode stack disposed within the cell housing. The electrode stack includes a pair of tabs in communication with a pair of terminals on the cell housing. An exhaust port is arranged in the battery cell shell, a pressure release valve is arranged in the battery cell shell, and the pressure release valve has lower pressure release pressure than the exhaust port.

Description

[0001] Introduction

[0002] The information provided in this section is for the purpose of generally presenting the context of the present disclosure. To the extent described in this section, the work of the currently named inventors and aspects that may not constitute prior art at the time of filing are neither expressly nor implicitly considered prior art to the present disclosure. Technical Field

[0003] The present disclosure relates to a battery cell design having a resealable pressure relief valve. Background Art

[0004] Early detection of cell venting (such as in the case of a thermal event) is useful for the control of lithium-ion batteries in electric vehicles. It has been observed that during the precursor stage of a thermal event, gases (such as H2) are generated inside the cell before the thermal event can be detected. It has also been observed that gas accumulation due to cycling during the life of the battery cell may lead to capacity fade. Summary of the Invention

[0005] According to one aspect of the present disclosure, a battery cell includes a cell housing and an electrode stack disposed within the cell housing. The electrode stack includes a pair of tabs in communication with a pair of terminals on the cell housing. An exhaust port is provided in the cell housing, and a pressure relief valve is provided in the cell housing, wherein the pressure relief valve has a lower pressure relief pressure than the exhaust port.

[0006] According to another aspect, the exhaust port is at a first end of the cell housing, and the pressure relief valve is at a second end of the cell housing opposite the first end.

[0007] According to another aspect, both the exhaust port and the pressure relief valve are at one end of the cell housing.

[0008] According to another aspect, the pressure relief valve is integrated into the exhaust port.

[0009] According to another aspect, the pressure relief valve includes a valve member biased to a closed position by a spring.

[0010] According to another aspect, the cell housing includes a membrane lining.

[0011] According to another aspect, the pressure relief valve has a release pressure between 50 - 300 kPa gauge pressure.

[0012] According to another aspect, the exhaust port has a burst pressure of at least 800 kPa.

[0013] The battery cell according to the present disclosure is designed to release gas from the cell by incorporating a resealable valve, enabling early cell heating detection through a battery pack sensor (H2 sensor) and improving cell performance maintenance through gas removal (>90% CO2). The resealable pressure relief valve can be any one-way valve with a specified opening pressure (i.e., 50 - 300 kPa gauge pressure), such as a check valve or a pressure relief valve. The valve can incorporate a breathable membrane to prevent electrolyte loss. In a prismatic or cylindrical cell, the pressure relief valve will open at a lower pressure than the cell vent. In a pouch cell, the pressure relief valve will open at a lower pressure than the pressure at which the pouch will rupture.

[0014] The present invention provides the following technical solutions.

[0015] Technical solution 1. A battery cell, comprising:

[0016] A cell housing;

[0017] An electrode stack disposed within the cell housing, the electrode stack including a pair of tabs in communication with a pair of terminals on the cell can;

[0018] A vent disposed in the cell housing; and

[0019] A pressure relief valve disposed in the cell housing, wherein the pressure relief valve has a lower pressure relief pressure than the vent.

[0020] Technical solution 2. The battery cell according to technical solution 1, wherein the vent is at a first end of the cell housing, and the pressure relief valve is at a second end of the cell can opposite the first end.

[0021] Technical solution 3. The battery cell according to technical solution 1, wherein both the vent and the pressure relief valve are at one end of the cell housing.

[0022] Technical solution 4. The battery cell according to technical solution 1, wherein the pressure relief valve is integrated into the vent.

[0023] Technical solution 5. The battery cell according to technical solution 1, wherein the pressure relief valve includes a valve member biased to a closed position by a spring.

[0024] Technical solution 6. The battery cell according to technical solution 1, further comprising a membrane lining the cell housing.

[0025] Technical solution 7. The battery cell according to technical solution 1, wherein the pressure relief valve has a release pressure between 50 - 300 kPa gauge pressure.

[0026] Technical solution 8. The battery cell according to technical solution 1, wherein the exhaust port has a bursting pressure of at least 800 kPa.

[0027] Technical solution 9. A battery cell, comprising:

[0028] A cell housing;

[0029] An electrode stack disposed within the cell housing, the electrode stack including a pair of tabs in communication with a pair of terminals on the cell housing;

[0030] An exhaust port disposed in the cell housing; and

[0031] A pressure relief valve disposed in the cell housing and including a valve member biased to a closed position by a spring, wherein the pressure relief valve has a lower pressure relief pressure than the exhaust port.

[0032] Technical solution 10. The battery cell according to technical solution 9, wherein the exhaust port is at a first end of the cell housing, and the pressure relief valve is at a second end of the cell housing opposite the first end.

[0033] Technical solution 11. The battery cell according to technical solution 9, wherein both the exhaust port and the pressure relief valve are at one end of the cell housing.

[0034] Technical solution 12. The battery cell according to technical solution 9, wherein the pressure relief valve is integrated into the exhaust port.

[0035] Technical solution 13. The battery cell according to technical solution 9, further comprising a film lining the cell housing.

[0036] Technical solution 14. The battery cell according to technical solution 9, wherein the pressure relief valve has a release pressure between 50 - 300 kPa gauge pressure.

[0037] Technical solution 15. A battery cell, comprising:

[0038] A cell housing;

[0039] An electrode stack disposed within the cell housing, the electrode stack including a pair of tabs in communication with a pair of terminals on the cell housing;

[0040] An exhaust port disposed in the cell housing; and

[0041] At least one of a temperature sensor and a pressure sensor disposed in the cell housing and communicating with a battery controller.

[0042] Technical solution 16. The battery cell according to technical solution 15, wherein the exhaust port is at the first end of the cell housing, and at least one of the temperature sensor and the pressure sensor is at the second end of the cell housing opposite to the first end.

[0043] Technical solution 17. The battery cell according to technical solution 15, further comprising a film lining the cell housing.

[0044] Technical solution 18. The battery cell according to technical solution 15, further comprising an insulating material surrounding the electrode stack.

[0045] Technical solution 19. The battery cell according to technical solution 15, wherein at least one of the temperature sensor and the pressure sensor comprises a temperature sensor, and when the internal temperature of the battery cell exceeds a predetermined level, the battery controller deactivates the battery cell.

[0046] Technical solution 20. The battery cell according to technical solution 15, wherein at least one of the temperature sensor and the pressure sensor comprises a pressure sensor, and when the internal pressure of the battery cell exceeds a predetermined level, the battery controller deactivates the battery cell.

[0047] From the detailed description, the claims and the drawings, other application fields of the present disclosure will become apparent. The detailed description and specific examples are only for illustrative purposes and are not intended to limit the scope of the present disclosure. Description of the Drawings

[0048] The present disclosure will be more fully understood from the detailed description and the drawings, wherein:

[0049] Figure 1 is a schematic diagram of a battery cell with an exhaust port and a pressure relief valve according to the principles of the present disclosure;

[0050] Figure 2 is a schematic diagram of a battery cell with an exhaust port and a pressure relief valve according to a second embodiment of the present disclosure;

[0051] Figure 3 is a schematic diagram of a battery cell with an exhaust port and a pressure relief valve according to a third embodiment of the present disclosure;

[0052] Figure 4 is a schematic diagram of a battery cell with an exhaust port and a pressure relief valve according to a fourth embodiment of the present disclosure;

[0053] Figure 5 is a schematic diagram of a battery cell with an exhaust port and a pressure relief valve according to a fifth embodiment of the present disclosure; and

[0054] Figure 6 Schematic diagram of a battery cell with an exhaust port and a temperature / pressure sensor according to a sixth embodiment of the present disclosure.

[0055] In the drawings, reference numerals may be reused to identify similar and / or identical elements. Detailed Description

[0056] The present disclosure relates to a battery cell design that incorporates a resealable valve, such as a check valve or a pressure relief valve, to allow gas generated in the cell to escape into the battery pack housing at a specified pressure below the exhaust port or bag opening pressure of a conventional cell. This allows the cell to vent gas while it continues to operate. The gas will move from the higher pressure inside the cell to the lower pressure outside the cell in only one direction, thus preventing moisture from entering the cell. A breathable membrane may be incorporated into the valve to prevent electrolyte loss. The gas can then be detected by a battery pack housing sensor, and corrective action can be taken.

[0057] Referring to Figure 1 , a prismatic battery cell 10 according to the principles of the present disclosure will now be disclosed. The prismatic battery cell 10 includes a cell housing 12 that may be lined with a membrane 14. The cell housing may include a can, a pouch, a prismatic box-shaped housing, or other known cell housings. An electrode stack 16 is disposed within the cell housing and a thermal gap that may be filled with one of an insulating filler, tape, or foam 18. The electrode stack 16 includes a pair of tabs 20 that communicate with a pair of terminals 22. The bottom of the cell housing 12 includes an exhaust port 24. The top of the cell housing 12 includes a pressure relief valve 26. The pressure relief valve 26 has a specified opening pressure that is lower than the burst pressure of the exhaust port 24, and the pressure relief valve 26 is reclosable after the pressure relief valve 26 is opened. The opening pressure of the pressure relief valve 26 may be tuned to a pressure (i.e., 50 - 300 kPa gauge pressure) to optimize thermal release detection and cell performance. As is known in the art, the cell exhaust port 24 is designed to open in response to a thermal runaway event. As a non-limiting example, the exhaust port 24 may have a burst pressure of 800 kPa. The exhaust port 24 may include a scored, notched, or otherwise weakened aluminum sheet that is designed to rupture at the designed burst pressure.

[0058] Referring to Figure 2, Prismatic battery cell 110 in accordance with the principles of the present disclosure will now be disclosed. The prismatic battery cell 110 includes a cell housing 12 that may be lined with a film 14. An electrode stack 16 is disposed within the cell can and a thermal gap that may be filled with one of a filler, tape, or foam 18. The electrode stack 16 includes a pair of tabs 20 that communicate with a pair of terminals 22. The top of the cell housing 12 includes a vent 24. The top of the cell housing 12 further includes a pressure relief valve 26. The pressure relief valve 26 has a specified opening pressure that is lower than the burst pressure of the vent 24, and the pressure relief valve 26 is re-closeable after the pressure relief valve 26 is opened. The opening pressure of the pressure relief valve 26 can be adjusted to a pressure (i.e., 50 - 300 kPa gauge pressure) to optimize thermal release detection and cell performance. As is known in the art, the cell vent 24 is designed to open in response to a thermal runaway event.

[0059] Reference Figure 3 , Prismatic battery cell 210 in accordance with the principles of the present disclosure will now be disclosed. The prismatic battery cell 210 includes a cell housing 12 that may be lined with a film 14. An electrode stack 16 is disposed within the cell can and a thermal gap that may be filled with one of a filler, tape, or foam 18. The electrode stack 16 includes a pair of tabs 20 that communicate with a pair of terminals 22. The top of the cell housing 12 includes a vent 24. The pressure relief valve 26 is integrated with the vent 24. The pressure relief valve 26 has a specified opening pressure that is lower than the burst pressure of the vent 24, and the pressure relief valve 26 is re-closeable after the pressure relief valve 26 is opened. The opening pressure of the pressure relief valve 26 can be adjusted to a pressure (i.e., 50 - 300 kPa gauge pressure) to optimize thermal release detection and cell performance. As is known in the art, the cell vent 24 is designed to open in response to a thermal runaway event.

[0060] Reference Figure 4, the prismatic battery cell 310 in accordance with the principles of the present disclosure will now be disclosed. The prismatic battery cell 310 includes a cell housing 12 that may be lined with a film 14. An electrode stack 16 is disposed within the cell housing and a thermal gap that may be filled with one of a filler, tape, or foam 18. The electrode stack 16 includes a pair of tabs 20 that communicate with a pair of terminals 22. The bottom of the cell housing 12 includes an exhaust port 24. The top of the cell housing 12 further includes a pressure relief valve 126. The pressure relief valve 126 has a specified opening pressure that is lower than the burst pressure of the exhaust port 24, and the pressure relief valve 126 is re-closable after it is opened. The pressure relief valve 126 may take alternative forms, including but not limited to a reed valve, a ball check valve, a piston check valve, and a lift valve. As a non-limiting example, the pressure relief valve 126 may include a valve body 100 having an inlet nozzle 102 that communicates with an outlet channel 128 of the cell can 12, and the valve body 100 includes a discharge port 104. A valve cover 106 is mounted to the valve body 100 with a seal 108 therebetween. A cap 110 may be mounted to the valve cover 106. A valve seat retainer 112 supports a valve member 114 against the inlet nozzle 102 and is biased to a closed position by a spring 116. A pressure regulating screw 118 is supported by the valve cover 106 within a cap 109 and may be adjusted to regulate the spring load on the valve seat retainer 112. The opening pressure of the pressure relief valve 126 may be tuned to a pressure (i.e., 50 - 300 kPa gauge pressure) to optimize thermal release detection and cell performance. As is known in the art, the cell exhaust port 24 is designed to open in response to a thermal runaway event. Referring to Figure 5 , a tube 120 may connect the pressure relief valve 126 to the outlet channel 128 of the cell housing 12 to provide flexibility in packaging the pressure relief valve 126.

[0061] Referring to Figure 6 , the prismatic battery cell 410 in accordance with the principles of the present disclosure will now be disclosed. The prismatic battery cell 410 includes a cell housing 12 that may be lined with a film 14. An electrode stack 16 is disposed within the cell can and a thermal gap that may be filled with one of a filler, tape, or foam 18. The electrode stack 16 includes a pair of tabs 20 that communicate with a pair of terminals 22. The bottom of the cell housing 12 includes an exhaust port 24. The top of the cell housing 12 includes at least one of a temperature / pressure sensor 50. The temperature / pressure sensor 50 senses at least one of the temperature and / or pressure of the battery cell. The temperature / pressure sensor 50 may be connected to a battery controller 52 that may be used to deactivate the battery cell 410 in response to the temperature and / or pressure exceeding a predetermined level indicative of a precursor stage of a thermal event. As is known in the art, the cell exhaust port 24 is designed to open in response to a thermal runaway event.

[0062] The present disclosure provides a novel cell design that incorporates a resealable valve with unidirectional flow (i.e., a check valve or pressure relief valve) and a specified opening pressure below the cell exhaust pressure to allow gas to escape from the cell while the cell continues to operate, thereby preventing performance degradation due to gas accumulation in the cell. The pressure relief valve 26 also allows gas generated by battery heating / TR to escape into the battery pack enclosure, enabling detection of the gas earlier than with traditional vent ports or pouch ruptures. The valve can also be used to release gas generated during formation. A breathable membrane can be incorporated into the valve to prevent electrolyte loss. The present disclosure can be applied to any cell form / design / chemistry, with or without an existing cell vent, to provide earlier venting of gas from the cell, thereby preventing degradation due to gas accumulation in the cell and allowing earlier detection of thermal runaway or cell heating.

[0063] The foregoing description is merely illustrative in nature and is in no way intended to limit the disclosure, its application, or uses. The broad teachings of the disclosure can be implemented in a variety of forms. Thus, while the disclosure includes specific examples, the true scope of the disclosure should not be so limited since other modifications will become apparent upon study of the drawings, the specification, and the appended claims. It should be understood that one or more steps in a method can be performed in a different order (or concurrently) without altering the principles of the disclosure. Additionally, although each of the embodiments is described above as having certain features, any one or more of those features described with respect to any embodiment of the disclosure can be implemented in and / or combined with the features of any other embodiment, even if the combination is not explicitly described. In other words, the described embodiments are not mutually exclusive, and the arrangement of one or more of the embodiments with respect to each other is still within the scope of the disclosure.

[0064] Spatial and functional relationships between elements (e.g., between modules, circuit elements, semiconductor layers, etc.) are described using various terms, including "connected," "engaged," "coupled," "adjacent," "next to," "on top of," "above," "below," and "disposed in." Unless explicitly described as "direct," when describing the relationship between a first element and a second element in the foregoing disclosure, the relationship can be a direct relationship where no other intermediate elements exist between the first and second elements, but can also be an indirect relationship (spatially or functionally) where one or more intermediate elements exist between the first and second elements. As used herein, the phrase "at least one of A, B, and C" should be interpreted to mean a logical (A or B or C) using non-exclusive logic "or" and should not be interpreted to mean "at least one of A, at least one of B, and at least one of C."

Claims

1. A battery cell, comprising: Battery cell housing; an electrode stack disposed in the battery cell housing, the electrode stack comprising a pair of protrusions communicating with a pair of terminals on the battery cell can; An exhaust port, which is arranged in the battery cell housing; and A pressure relief valve is disposed in the battery cell housing, wherein the pressure relief valve has a lower pressure relief pressure than the exhaust port.

2. The battery cell according to claim 1, wherein: The vent is at a first end of the cell case, and the pressure relief valve is at a second end of the cell can opposite the first end.

3. The battery cell according to claim 1, wherein: The exhaust port and the pressure relief valve are both at one end of the cell case.

4. The battery cell according to claim 1, wherein: The pressure relief valve is integrated into the exhaust port.

5. The battery cell according to claim 1, wherein: The pressure relief valve includes a valve member biased to a closed position by a spring.

6. The battery cell of claim 1 further comprising a film lining the cell casing.

7. The battery cell according to claim 1, wherein: The pressure relief valve has a release pressure between 50-300 kPa gauge pressure.

8. The battery cell according to claim 1, wherein: The vent has a burst pressure of at least 800 kPa.

9. A battery cell, comprising: Battery cell housing; an electrode stack disposed in the cell housing, the electrode stack comprising a pair of protrusions communicating with a pair of terminals on the cell housing; An exhaust port, which is arranged in the battery cell housing; and A pressure relief valve is disposed in the cell case and includes a valve member biased to a closed position by a spring, wherein the pressure relief valve has a lower relief pressure than the exhaust port.

10. A battery cell comprising: Battery cell housing; an electrode stack disposed in the cell housing, the electrode stack comprising a pair of protrusions communicating with a pair of terminals on the cell housing; An exhaust port, which is arranged in the battery cell housing; and At least one of a temperature sensor and a pressure sensor is disposed in the battery cell housing and communicates with a battery controller.

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