Battery pressure control

Abstract

A pressure control device for a battery cell includes a housing in which the battery cell is positioned and a cell plate movably positioned in the housing and dividing an interior of the housing into a cell chamber having the battery cell therein and a pressure chamber having a volume of pressurized fluid therein. The apparatus also includes a valve configured to allow a portion of the pressurized fluid to be removed from the pressure chamber when the pressure in the pressure chamber exceeds a threshold.

Description

Technical Field

[0001] The present disclosure relates to rechargeable energy storage devices for use, for example, in electric vehicles. Background Art

[0002] Rechargeable energy storage devices, such as lithium metal battery cells, are typically confined to a fixed volume, thereby applying an initial external pressure to the battery structure. This initial pressure helps prevent the growth of lithium dendrites. However, during cycling of the battery, the internal battery pressure continues to increase and can cause performance degradation after many cycles.

[0003] It would be desirable to provide a battery securing device to prevent dendrite formation while also preventing separator rupture. Summary of the invention

[0004] In one exemplary embodiment, a pressure control device for a battery cell includes a housing in which the battery cell is positioned and a cell plate that is movably positioned in the housing and divides the interior of the housing into a cell chamber having the battery cell therein and a pressure chamber having a volume of pressurized fluid therein. The device also includes a valve configured to allow a portion of the pressurized fluid to be removed from the pressure chamber when the pressure in the pressure chamber exceeds a threshold value.

[0005] In addition to one or more features described herein, a fluid pump may be operably connected to the pressure chamber to pressurize the pressure chamber with the fluid.

[0006] In addition to one or more features described herein, the valve is a passive check valve.

[0007] In addition to one or more features described herein, one or more pressure sensors are located in the pressure chamber, and the valve is operated in response to a pressure exceeding a threshold value detected by the one or more pressure sensors.

[0008] In addition to one or more features described herein, the secondary pressure chamber is located in the housing, and the valve controls fluid flow between the pressure chamber and the secondary pressure chamber.

[0009] In addition to one or more features described herein, the valve is a solenoid actuated valve.

[0010] In addition to one or more features described herein, the pressure in the pressure chamber increases in response to an increase in the size of the battery cell.

[0011] In another exemplary embodiment, a battery cell assembly of a vehicle includes a housing located at the vehicle and a battery cell located in the housing. The battery cell includes a cathode, an anode, and a separator located between the cathode and the anode. A pressure control device is operably connected to the battery cell and includes a cell plate that is movably positioned in the housing and separates the interior of the housing into a cell chamber having a battery cell therein and a pressure chamber having a certain volume of pressurized fluid therein. The valve is configured to allow a portion of the pressurized fluid to be removed from the pressure chamber when the pressure in the pressure chamber exceeds a threshold value.

[0012] In addition to one or more features described herein, a fluid pump may be operably connected to the pressure chamber to pressurize the pressure chamber with the fluid.

[0013] In addition to one or more features described herein, the valve is a passive check valve.

[0014] In addition to one or more features described herein, one or more pressure sensors are positioned in the pressure chamber, and the valve is operated in response to a pressure exceeding a threshold value detected by the one or more pressure sensors.

[0015] In addition to one or more features described herein, a secondary pressure chamber is positioned in the housing, and a valve controls fluid flow between the pressure chamber and the secondary pressure chamber.

[0016] In addition to one or more features described herein, the valve is a solenoid actuated valve.

[0017] In addition to one or more features described herein, the pressure in the pressure chamber increases in response to an increase in the size of the battery cell.

[0018] In addition to one or more features described herein, the battery cell is a lithium metal battery cell.

[0019] In yet another exemplary embodiment, a method of regulating external pressure on a battery cell of a vehicle includes positioning the battery cell in a housing located at the vehicle, the housing defining a battery cell chamber in which the battery cell is located and a pressure chamber in which a volume of pressurized fluid is included. The method also includes increasing the volume of the battery cell via cycling of the battery cell, and in response to the increase in the volume of the battery cell, reducing the volume of the fluid in the pressure chamber when the fluid pressure exceeds a threshold, thereby reducing the external pressure on the battery cell.

[0020] In addition to one or more features described herein, fluid pressure in the pressure chamber is measured via one or more pressure sensors located in the pressure chamber, and the valve is operated to reduce the volume of the fluid in the pressure chamber in response to the measured pressure exceeding a threshold.

[0021] In addition to one or more features described herein, reducing the fluid volume in the pressure chamber includes moving a portion of the fluid volume to a secondary chamber positioned in the housing.

[0022] In addition to one or more features described herein, the method includes operating a pump operably connected to the pressure chamber to pressurize a volume of fluid to an initial pressure.

[0023] In addition to one or more features described herein, reducing the volume of the fluid includes passively operating a check valve located at the pressure chamber when a pressure of the fluid exceeds a threshold value.

[0024] The above features and advantages and other features and advantages of the present disclosure are apparent from the following detailed description when taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Other features, advantages and details appear, by way of example only, from the following detailed description, which refers to the accompanying drawings, in which:

[0026] Figure 1 is a schematic diagram of the vehicle;

[0027] Figure 2 is a schematic diagram of an apparatus of an embodiment of pressure control of a battery cell;

[0028] Figure 3 is a cross-sectional view of an embodiment of a check valve;

[0029] Figure 4 is a schematic diagram of another device for controlling pressure of a battery cell;

[0030] Figure 5 is a schematic diagram of another device of an embodiment of pressure control of a battery cell; and

[0031] Figure 6 FIG. 4 is a schematic diagram of another device for controlling the pressure of a battery cell. DETAILED DESCRIPTION

[0032] The following description is merely exemplary in nature and is not intended to limit the present disclosure, its application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate the same or corresponding parts and features.

[0033] According to an exemplary embodiment, a vehicle according to a non-limiting example is Figure 110. The vehicle 10 includes a body 12 supported on a plurality of wheels 16. In a non-limiting example, two of the plurality of wheels 16 are steerable. The body 12 partially defines a passenger compartment 20 having a seat 22 positioned behind an instrument panel 26. A steering controller 30 is disposed between the seat 22 and the instrument panel 26. The steering controller 30 is operated to control the orientation of the steerable wheels. The vehicle 10 includes an electric motor 34 connected to a transmission that provides power to one or more of the plurality of wheels 16. A rechargeable energy storage system (RESS) 38 or battery assembly provides power to the electric motor 34.

[0034] The RESS 38 may include one or more battery cells 40, an exemplary embodiment of which is Figure 2 . In some embodiments, the battery cell 40 is a lithium metal battery cell. The battery cell 40 includes a cathode 42 and an anode 44, and a separator 46 is disposed between the cathode 42 and the anode 44. The battery cell 40 is disposed in a housing 48 and includes a cell plate 50 extending through the battery cell 40 in the housing 48. The cell plate 50 is movable in the housing 48 and divides the interior of the housing 48 into a cell chamber 52 and a pressure chamber 54, wherein the cathode 42, the anode 44 and the separator 46 are disposed in the cell chamber 52. The pressure chamber 54 is part of a fluid circuit 56, in which a certain volume of compressed liquid, such as a hydraulic fluid, is provided to maintain the internal pressure of the pressure chamber 54 at or below a preselected threshold. Maintaining the selected pressure in the pressure chamber 54 maintains a desired external pressure on the battery cell 40.

[0035] The pressure chamber 54 includes a fluid inlet 58 and a fluid outlet 60, wherein a check valve 62 is connected to the fluid outlet 60, so that when the fluid pressure in the pressure chamber 54 exceeds a preselected threshold, for example, due to the volume increase of the battery cell 40 caused by the cycling of the battery cell 40, the check valve 62 automatically opens and allows excess fluid to leave the pressure chamber 54 through the fluid outlet 60 until the fluid pressure drops below the threshold. The excess fluid is directed to the fluid reservoir 64 via the outlet path 66.

[0036] In some embodiments, a check valve 62 is provided at the fluid outlet 60, while in other embodiments, the check valve 62 may be located along the outlet passage 66. The fluid reservoir 64 is connected to the fluid inlet 58 via an inlet passage 68, and a pump 70 is located along the inlet passage 68 to push fluid from the fluid reservoir 64 into the pressure chamber 54 when activated to pressurize the pressure chamber 54. The pump 70 may be driven by a motor 72, and in some embodiments, a pressure relief valve 74 is located along the inlet passage 68.

[0037] Reference now Figure 3, shows an embodiment of a check valve 62. The check valve 62 includes a valve body 76 having a valve inlet 78 and a valve outlet 80. A valve element 82 (such as a ball) is disposed in the valve body 76 and is biased to a closed position by, for example, a spring 84 so that the valve element 82 blocks fluid from passing through the valve body 76. When the fluid pressure in the pressure chamber 54 (such as Figure 2 When the threshold is exceeded, the biasing force of the spring 84 is overcome and the valve element 82 moves to the open position, thereby allowing fluid to flow toward the fluid reservoir 64 through the check valve 62 ( Figure 2 When the pressure in the pressure chamber 54 drops below the threshold, the biasing force is greater than the fluid pressure and the valve element 82 returns to the closed position. It will be readily appreciated by those skilled in the art that different thresholds may be utilized by, for example, changing the biasing force by changing the spring 84.

[0038] Reference now Figure 4 , another embodiment is shown, in which the pressure chamber 54 is defined by two overlapping chamber portions 86a and 86b, with a sealing element 88 between the two overlapping chamber portions 86a and 86b to seal the pressure chamber 54. Each chamber portion 86a, 86b has a chamber base 90a and 90b and chamber walls 92a and 92b extending from the chamber base 90a and 90b. The chamber base 90a of the first chamber portion 86a is fixed to the unit plate 50 and can move with it as the volume of the battery cell 40 changes. The second chamber portion 86b is fixed to the housing 48, wherein the chamber wall 92b of the second chamber portion 86b extends toward the chamber base 90a of the first chamber portion 86a. Similarly, the chamber wall 92a of the first chamber portion 86a extends toward the chamber base 90b of the second chamber portion 86b, so that the chamber walls 92a and 92b overlap to define the pressure chamber 54. In some embodiments, pressure chamber 54 may have a circular cross-section, but those skilled in the art will readily appreciate that other cross-sectional shapes may be used, such as elliptical, rectangular, or rounded rectangular. Figure 4 The pressure chamber 54 configuration reduces the volume of fluid required to produce a selected pressure in the pressure chamber 54, and pressure is more easily controlled with a smaller volume of fluid than with a larger volume.

[0039] In another embodiment, Figure 5 As shown, the fluid pressure in the pressure chamber 54 is controlled by one or more electronically controlled valves 94, which are operably connected to one or more pressure sensors 96. The pressure sensor 96 is disposed in the pressure chamber 54 and detects the fluid pressure in the pressure chamber 54. When the detected pressure exceeds a threshold value, the electronically controlled valve 94 is commanded to open to allow fluid to flow from the pressure chamber 54 to the fluid reservoir 64.

[0040] exist Figure 6, the pressure chamber 54 in the housing 48 includes a fixed chamber dividing wall 98 that divides the pressure chamber 54 into a main chamber 102 and a secondary chamber 100. In some embodiments, a valve 104 operated by a solenoid actuator can selectively allow fluid to flow between the secondary chamber 100 and the main chamber 102. For example, as the fluid pressure in the main chamber 102 increases, the valve 104 can open to transfer the fluid to the secondary chamber 100. Similarly, when the fluid pressure in the main chamber 102 decreases, the valve 104 can open to allow fluid to flow from the secondary chamber 100 to the main chamber 102.

[0041] The use of the configuration herein allows the operating pressure of the battery cell 40 to be regulated via a hydraulic fluid device (either passively or actively via a check valve, for example). This reduces the incidence of diaphragm failure in the battery cell 40.

[0042] The terms "one" and "an" do not indicate a limitation of quantity, but rather indicate the presence of at least one of the referenced item. Unless the context clearly indicates otherwise, the term "or" means "and / or". References to "aspects" throughout the specification mean that a particular element (e.g., a feature, structure, step, or characteristic) described in conjunction with that aspect is included in at least one aspect described herein, and may or may not be present in other aspects. In addition, it should be understood that the described elements may be combined in any suitable manner in the various aspects.

[0043] When an element such as a layer, film, region, or substrate is referred to as being "on" another element, it can be directly on the other element or intervening elements may also be present. In contrast, when an element is referred to as being "directly on" another element, there are no intervening elements present.

[0044] Unless defined otherwise, technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

[0045] Although the above disclosure has been described with reference to exemplary embodiments, it will be appreciated by those skilled in the art that various changes may be made and equivalents may be substituted for its elements without departing from its scope. In addition, many modifications may be made to adapt specific circumstances or materials to the teachings of the disclosure without departing from the basic scope of the disclosure. Therefore, it is intended that the disclosure is not limited to the specific embodiments disclosed, but will include all embodiments falling within its scope.

Claims

1. A pressure control device for a battery cell, comprising: a housing in which the battery unit is disposed; A unit plate is movably disposed in the housing and divides the interior of the housing into: a cell chamber, wherein the battery cell is disposed in the cell chamber; as well as a pressure chamber having a volume of pressurized fluid therein; as well as A valve is configured to allow removal of a portion of the pressurized fluid from the pressure chamber when the pressure in the pressure chamber exceeds a threshold value.

2. The pressure control device of claim 1, further comprising a fluid pump operably connected to the pressure chamber to pressurize the pressure chamber with a fluid.

3. The pressure control device according to claim 1, wherein: The valve is a passive check valve.

4. The pressure control device according to claim 1 further comprises one or more pressure sensors arranged in the pressure chamber, wherein the valve operates in response to a pressure exceeding a threshold value detected by the one or more pressure sensors.

5. The pressure control device according to claim 1, further comprising a secondary pressure chamber provided in the housing, wherein the valve controls a fluid flow between the pressure chamber and the secondary pressure chamber.

6. The pressure control device according to claim 5, wherein: The valve is a solenoid actuated valve.

7. The pressure control device according to claim 1, wherein: The pressure in the pressure chamber increases in response to an increase in the size of the battery cell.

8. A method of regulating external pressure on a battery cell of a vehicle, comprising: Positioning the battery unit in a housing located at the vehicle, the housing defining: a cell chamber, wherein the battery cell is located in the cell chamber; as well as a pressure chamber containing a volume of pressurized fluid; increasing the volume of the battery cell through cycling of the battery cell; as well as In response to the increase in volume of the battery cell, the volume of the fluid in the pressure chamber is reduced when the fluid pressure exceeds a threshold, thereby reducing external pressure on the battery cell.

9. The method according to claim 8, further comprising: measuring the fluid pressure in the pressure chamber via one or more pressure sensors disposed in the pressure chamber; as well as A valve is operated in response to the measured pressure exceeding a threshold value to reduce the volume of the fluid in the pressure chamber.

10. The method according to claim 8, wherein: Reducing the volume of the fluid in the pressure chamber includes moving a portion of the volume of the fluid to a secondary chamber disposed in the housing.

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