Pressure control of battery cells

Abstract

A pressure management system includes a pressure plate configured to be disposed at an initial position relative to a battery cell in a housing, the initial position including a first orientation, and a tilt assembly configured to allow the pressure plate to change from the first orientation to a second orientation based on a non-uniform expansive force. The system includes a mechanical linkage attached to the pressure plate and configured to move laterally in response to the expansive force and to convert the expansive force into a reaction force, and a biasing system including a biasing member configured to resist lateral movement of the mechanical linkage. The biasing system is configured to apply a biasing force that causes the mechanical linkage to apply a reaction force, and based on a non-uniform expansive force, the biasing system is controllable to change the biasing force to balance an internal pressure of the battery cell.

Description

Technical Field

[0001] The present disclosure relates to battery systems, and more particularly to managing pressure of battery cells of a battery system. Background Art

[0002] Battery pouch cells are used in a variety of applications, such as automotive applications (e.g., in electric and hybrid vehicles). For example, electric and hybrid vehicles include a battery system that includes a battery pack that houses a plurality of battery cells, which may include pouch-type battery cells, such as lithium-ion battery cells. As such batteries charge and discharge, and as such batteries age, pressures may change, which may be detrimental to charging and power storage capabilities. It is desirable to provide a mechanism for maintaining a battery cell at a substantially constant pressure during the operating life of the battery cell. Summary of the invention

[0003] In an exemplary embodiment, a pressure management system includes a pressure plate and a tilt assembly, the pressure plate being configured to be disposed in an initial position relative to a battery cell disposed in a housing, the initial position including a first orientation, wherein expansion of the battery cell causes an expansion force to be applied to the pressure plate, and the tilt assembly being configured to allow the pressure plate to change from the first orientation to a second orientation based on a non-uniform expansion force. The pressure management system also includes a mechanical linkage attached to the pressure plate, the mechanical linkage being configured to move laterally in response to the expansion force and convert the expansion force into a reaction force opposite to the expansion force, and a biasing system including a biasing member configured to resist lateral movement of the mechanical linkage. The biasing system is configured to apply a biasing force in a direction opposite to the direction of the lateral movement, the biasing force causing the mechanical linkage to apply a reaction force as a selected proportion of the expansion force, and based on the non-uniform expansion force, the biasing system is controllable to change the biasing force and the reaction force to balance the internal pressure of the battery cell.

[0004] In addition to one or more features described herein, a surface of the pressure panel defines a plane normal to the direction of the expansion force when the pressure panel is in the first orientation, and the surface defines an angle relative to the plane when the pressure panel is in the second orientation.

[0005] In addition to one or more features described herein, the tilt assembly includes a wheel attached to an end of the pressure plate, the wheel configured to engage and rotate along a sidewall of the housing.

[0006] In addition to one or more features described herein, the biasing member has a spring constant selected such that the biasing force causes the reaction force to be a selected proportion of the expansion force.

[0007] In addition to one or more features described herein, the biasing system includes a biasing control coupled to the pressure plate, the biasing control configured to be operated to adjust a biasing force of the biasing member.

[0008] In addition to one or more features described herein, the bias control is configured to limit lateral movement of the mechanical linkage by directing a portion of a lateral force generated by the mechanical linkage toward the battery cell based on a reaction force generated by the bias control.

[0009] In addition to one or more features described herein, the biasing member is a spring having a first end configured to be coupled to the mechanical linkage and a second end connected to the biasing control.

[0010] In addition to one or more features described herein, the biasing system includes a set of sensors configured to measure parameters related to the internal pressure, and a controller configured to estimate a pressure imbalance based on the measured parameters and control the biasing control device to balance the internal pressure.

[0011] In addition to one or more features described herein, the bias control device includes a pinion coupled to the linear gear, the pinion connected to an actuator, the actuator configured to rotate the pinion to adjust the bias force.

[0012] In another exemplary embodiment, a method for controlling the pressure of a battery cell includes receiving an expansion force at a pressure plate disposed at an initial position relative to the battery cell, the battery cell being disposed in a housing, the initial position comprising a first orientation, the expansion force being generated by the expansion of the battery cell, the pressure plate being coupled to a tilt assembly, the tilt assembly being configured to allow the pressure plate to change from the first orientation to a second orientation based on a non-uniform expansion force. The method also includes managing the pressure of the battery cell through a pressure management system, the pressure management system comprising a mechanical linkage device and a biasing system attached to the pressure plate, wherein managing the pressure includes converting the expansion force into a reaction force based on lateral movement of the mechanical linkage device, the reaction force being configured to be opposite to the expansion force. Managing the pressure also includes controlling the reaction force based on the lateral movement of the mechanical linkage device being resisted by a biasing member of the biasing system, the biasing system applying a biasing force in a direction opposite to the direction of the lateral movement, the biasing force causing the mechanical linkage device to apply the reaction force as a selected proportion of the expansion force, and adjusting the biasing force and the reaction force to balance the internal pressure of the battery cell based on the non-uniform expansion force.

[0013] In addition to one or more features described herein, the tilt assembly includes a wheel attached to an end of the pressure plate, the wheel configured to engage and rotate along a sidewall of the housing.

[0014] In addition to one or more features described herein, the biasing member has a spring constant selected such that the biasing force causes the reaction force to be a selected proportion of the expansion force.

[0015] In addition to one or more features described herein, the biasing system includes a biasing control coupled to the pressure plate, the biasing control configured to be operated to adjust a biasing force of the biasing member.

[0016] In addition to one or more features described herein, the bias control is configured to limit lateral movement of the mechanical linkage by directing a portion of a lateral force generated by the mechanical linkage toward the battery cell based on a reaction force generated by the bias control.

[0017] In addition to one or more features described herein, the biasing system includes a set of sensors configured to measure parameters related to the internal pressure, and a controller configured to estimate a pressure imbalance based on the measured parameters and control the biasing control device to balance the internal pressure.

[0018] In addition to one or more features described herein, the bias control device includes a pinion coupled to the linear gear, the pinion connected to the actuator, and adjusting the bias force includes rotating the pinion via the actuator.

[0019] In yet another exemplary embodiment, a vehicle system includes a battery system connected to an electric motor of a vehicle, the battery system including a battery cell disposed in a housing, and a pressure management system including a pressure plate disposed at an initial position relative to the battery cell, the battery cell disposed in the housing, the initial position including a first orientation, wherein expansion of the battery cell causes an expansion force to be applied to the pressure plate. The pressure management system also includes a tilt assembly configured to allow the pressure plate to change from the first orientation to a second orientation based on a non-uniform expansion force, a mechanical linkage attached to the pressure plate, the mechanical linkage configured to move laterally in response to the expansion force and convert the expansion force into a reaction force opposite to the expansion force, and a biasing system including a biasing member configured to resist lateral movement of the mechanical linkage. The biasing system is configured to apply a biasing force in a direction opposite to the direction of the lateral movement, the biasing force causing the mechanical linkage to apply a reaction force as a selected proportion of the expansion force, and based on the non-uniform expansion force, the biasing system is controllable to change the biasing force and the reaction force to balance the internal pressure of the battery cell.

[0020] In addition to one or more features described herein, the tilt assembly includes a wheel attached to an end of the pressure plate, the wheel configured to engage and rotate along a sidewall of the housing.

[0021] In addition to one or more features described herein, the bias system includes a bias control device connected to the pressure plate, the bias control device is configured to operate to adjust the bias force of the biasing member, and the bias control device is configured to limit lateral movement of the mechanical linkage device, and a portion of the lateral force generated by the mechanical linkage device is directed toward the battery cell based on a reaction force generated by the bias control device.

[0022] In addition to one or more features described herein, the biasing system includes a set of sensors configured to measure parameters related to the internal pressure, and a controller configured to estimate a pressure imbalance based on the measured parameters and control the biasing control device to balance the internal pressure.

[0023] 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

[0024] Other features, advantages and details appear, by way of example only, from the following detailed description, which refers to the accompanying drawings, in which:

[0025] Figure 1 An energy storage system including a housing holding one or more battery cells and a pressure management system according to an exemplary embodiment is depicted;

[0026] Figure 2A and Figure 2B An energy storage system including a pressure management system including one or more mechanical linkages and a biasing system is depicted according to an exemplary embodiment;

[0027] Figure 3 schematically illustrates a pressure management system according to an exemplary embodiment;

[0028] Figure 4 A conventional pressure management system is schematically shown;

[0029] Figure 5 It is depicted with Figure 4 Parameters of conventional pressure management systems compared to Figure 3 A graph of parameters of a pressure management system;

[0030] FIG. 6A to FIG. 6C is a diagram illustrating a mechanical linkage and a Figure 2A and Figure 2B Force diagram of various forces generated by the cooperation of the biasing system;

[0031] Fig. 7A and Figure 7BAn energy storage system according to an exemplary embodiment is depicted that includes a pressure management system including one or more mechanical linkages and a biasing system attached to a pressure plate and a tilt system or tilt assembly that allows the pressure plate to tilt or otherwise change orientation;

[0032] Fig. 8A and Figure 8B An energy storage system including a pressure management system including one or more mechanical linkages and an adjustable biasing system attached to a pressure plate is depicted according to an exemplary embodiment;

[0033] Fig.9A and Fig. 9B Depicted is an exemplary device Fig. 8A and Figure 8B An adjustment embodiment of the bias system;

[0034] Fig.10 An energy storage system according to an exemplary embodiment is depicted, the energy storage system including a pressure management system including one or more mechanical linkages and an adjustable biasing system attached to a pressure plate, and a control architecture for adjusting the biasing system to control an internal pressure of a battery cell;

[0035] Fig.11 An energy storage system according to an exemplary embodiment is depicted, the energy storage system including a pressure management system including one or more mechanical linkages and an adjustable biasing system attached to a pressure plate, and a control architecture for adjusting the biasing system to control an internal pressure of a battery cell;

[0036] Fig.12 is a flow chart describing a method of managing pressure in a battery system according to an exemplary embodiment;

[0037] Fig.13 depicts a motor vehicle including a battery system and a pressure management system according to an exemplary embodiment; and

[0038] Fig.14 A computer system according to an exemplary embodiment is depicted. DETAILED DESCRIPTION

[0039] 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.

[0040] According to one or more exemplary embodiments, methods, devices, and systems for controlling pressure in battery assemblies and battery systems are provided. An embodiment of a pressure management system includes a pressure plate disposed in a housing of a battery assembly (e.g., a battery pack or a battery module) and movable in response to an expansion force generated by the expansion of one or more battery cells in the housing. The pressure management system also includes one or more mechanical linkages that convert a portion of the expansion force into a reaction force or reverse force to maintain or achieve a desired pressure in the battery cell, or otherwise compensate for changes in pressure and / or volume of the battery cell. In one embodiment, the pressure management system includes a biasing system that cooperates with the mechanical linkage to generate a reverse force. The biasing system can be controllable to control the internal pressure of the battery cell.

[0041] In one embodiment, the mechanical linkage includes a first elongated member (referred to as a "pivot member") and a second elongated member (referred to as a "connecting member"). The pivot member is attached to the pressure plate at one end, for example, by a pivot, and is attached to one end of the connecting member at the other end by another pivot. The pivot member is also attached to a fixed pivot that is attached to the housing. When an expansion force is applied to the pressure plate, movement of the pressure plate causes the end of the connecting member to move laterally (i.e., along the pressure plate and / or in a direction orthogonal to the direction of the expansion force) toward a stop member. When the connecting member engages the stop member, the lateral force applied by the connecting member is converted into a reaction force or reverse force proportional to the expansion force. Embodiments of pressure management can be configured to provide a reverse force proportional to the expansion force.

[0042] In an embodiment, the pressure management system includes a biasing system that is selectable to control the reverse force (e.g., to make the reverse force a desired proportion of the expansion force). For example, the biasing system includes a laterally extending spring attached to a stop member. When the connecting member moves a given distance, the connecting member engages the spring, and the spring applies a spring force that resists the movement of the connecting member. The magnitude of the spring force can be calibrated or adjusted, for example, by selecting a spring with an appropriate spring constant and / or by incorporating a spring adjuster that can be actuated to modify the spring force.

[0043] In one embodiment, the pressure management system is configured to have (or move to) a variable tilt or orientation, which allows the pressure management system to maintain balanced pressure under conditions where the expansion force is uneven. For example, the pressure plate is coupled to opposing wheels that allow the ends of the plate to move along one or more sides of the housing. Embodiments are not limited to wheels, as embodiments may include any component or mechanism that allows the pressure plate to tilt and apply balanced or uniform pressure in one or more battery cells.

[0044] In an embodiment, the biasing system is controllable so that the biasing system is adjusted to compensate for pressure imbalances in one or more battery cells. For example, a spring adjuster is controllable to change the ratio of the expansion forces applied to the battery. For example, the pressure management system includes a mechanical linkage at each side of the pressure plate. A spring or other biasing member is coupled to each linkage and attached to a spring adjuster. If the expansion force (local expansion force) at one linkage is different from the expansion force at another linkage, a spring adjuster is used to adjust the biasing force of one or more springs so that the local expansion forces are equal or within the desired difference.

[0045] The embodiments described herein present many advantages and technical effects. The embodiments provide improved battery functionality by maintaining a constant force on the battery cell during the life of the battery cell, thereby effectively controlling the pressure and avoiding negative effects such as dendrite growth. In addition, the embodiments provide effective pressure control that requires a smaller volume than existing systems. In addition, the embodiments are able to maintain the desired battery cell pressure under uniform conditions (i.e., conditions where the expansion force is uniform on the pressure plate) and non-uniform conditions (i.e., conditions where the expansion is uneven and the opposing force is unbalanced).

[0046] Embodiments are advantageous compared to existing pressure compensation systems. For example, existing systems may employ springs to resist expansion forces; however, such systems require a significant increase in the volume required for the battery module or housing to accommodate springs with sufficient spring force to maintain the desired pressure. Embodiments can provide effective pressure management in a relatively small volume.

[0047] Figure 1 An embodiment of an energy storage device or system 10 is depicted that includes a battery module 12 housing a group (i.e., one or more) of battery cells 14. Each battery cell 14 may be any type of cell that is rechargeable, such as a lithium-based battery cell (e.g., lithium-ion, lithium metal (LMB), etc.). For example, each battery cell 14 is a pouch-type lithium-ion battery cell.

[0048] The module 12 includes a housing 16 in which one or more battery cells 14 are disposed. If multiple battery cells are housed, they may be stacked as shown, with adjacent battery cells 12 separated by support plates 18. It should be noted that the embodiments described herein are not limited to the type or size of the housing 16, the type, size, or number of battery cells shown, or the type of battery cells shown.

[0049] The battery module 12 includes or is coupled to a pressure management system 20 that is configured to provide automatic management of pressure in the battery cells 14. The pressure management system 20 includes a pressure plate 22 disposed above the cells 14. The pressure plate 22 has a default position, which may be a position where the pressure plate 22 contacts the battery cells 14 (e.g., rests on the uppermost battery cell 14). Alternatively, as Figure 1 As shown, the default position defines a gap or clearance that allows a certain amount of battery cell expansion before triggering pressure compensation or management. It should be noted that the pressure plate 22 can be disposed in any position or location (e.g., below the battery cell 14) so ​​that expansion of the battery cell causes movement of the pressure plate 22.

[0050] The pressure compensation device is disposed on or otherwise connected to the pressure plate 22 and is configured to apply a reaction force on the pressure plate to compensate for expansion of the battery cells 14 and maintain the battery cells 14 at a desired pressure (or within a desired pressure range).

[0051] The pressure compensation device includes a set (i.e., one or more) of mechanical linkages 24 that convert the force on the pressure plate 22 into an opposing force (i.e., in the opposite direction of the expansion force). For example, when the battery cell 14 expands and exerts an upward force on the pressure plate, the mechanical linkages 24 operate to exert a proportional downward force. Each linkage 24 can be calibrated to provide a downward force that maintains a constant selected pressure on the battery cell as the battery cell expands.

[0052] like Figure 1 As shown, the pressure compensation device includes two linkages (links) 24 at opposite ends of a pressure plate 22. The pressure plate 22 is oriented so that a surface 23 facing the unit 14 defines a plane orthogonal to the expansion direction. For example, the expansion direction is along the z-axis (i.e., in the z-direction), and the surface is parallel to the plane defined by the x-axis and the y-axis. The pressure plate 22 can be configured so that the orientation of the pressure plate 22 is constant, or can be configured to be able to tilt in response to uneven expansion forces, as further discussed herein.

[0053] Each mechanical linkage 24 includes a first member 26 ("pivot member") positioned at a fixed pivot point P0 (i.e., a pivot point having a fixed position relative to the housing 16) relative to the housing 16, about which the pivot member 26 can rotate. One end of the pivot member 26 is attached to the pressure plate 22 at the pivot point P1 so that the pivot member 26 can rotate about the pivot point P1. The other end of the pivot member 26 is attached to one end of the connecting member 28 at the pivot point P2.

[0054] The opposite end of the connecting member 28 is coupled to the pressure plate 22 so that when the force due to expansion (referred to as F e The "expansion force" (denoted by t When the expansion force F e , pushing the plate upward (in the z-direction). This causes pivot member 26 to rotate about pivot point P0. The rotation of pivot member 26, in turn, causes end 30 of connecting member 28 and point P3 to move laterally (e.g., in the x-direction) or apply a lateral force toward the center of pressure plate 22. A "lateral" direction may be a direction orthogonal to the direction of the expansion force (e.g., in the xy plane), and / or may be a direction along the surface of pressure plate 22 (e.g., a direction in the plane defined by surface 23).

[0055] The pressure plate 22 includes or is attached to a stop member 32, which may be a raised structure that counteracts lateral movement of the connecting member 28. When the connecting member 28 engages the stop member 32, the counteracting lateral force results in a reaction force (also referred to as F r The “reverse force” represented by F is applied to the battery cell 14. r and expansion force F e The parameters of the mechanical linkage 24 may be selected to calibrate the mechanical linkage 24 to achieve a desired ratio of opposing forces. Examples of these parameters include the lengths of the pivot member 26 and the connecting member 28, the height of the pivot point P1, the location of the pivot point P2, the location of the stop member 32, etc. As discussed further herein, the parameters of the biasing system may also be selected or adjusted to calibrate the pressure management system 20.

[0056] In one embodiment, the pressure management system 20 includes a biasing system that provides one or more components configured to control the opposing force F r The amount of expansion force F e The biasing system may be a passive or active system that can be designed to maintain and / or adjust the desired ratio.

[0057] Figure 2A and Figure 2B An embodiment of the pressure management system 20 is shown in which the system is a passive system. In this embodiment, the pressure management system 20 includes laterally extending springs 34 configured to resist lateral movement of each connecting member 28. Each spring 34 applies a biasing force opposing the lateral movement. Figure 2A The pressure plate 22 is shown in an initial or default position where the default opposing force F d applied to the battery cell 14 .

[0058] As shown, each spring 34 is connected or attached to the stop member 32 at one end of the spring 34. The other end of each spring 34 is located laterally away from the stop member 32 and is configured to engage with the corresponding connecting member 28.

[0059] The biasing force is a function of the spring constant k of the spring 34. When the battery cell 14 expands and applies an expansion force to the pressure plate 22, the upward movement of the pressure plate 22 causes each pivot member 24 to rotate about the fixed pivot point P0, which in turn causes the connecting member 28 to move laterally and exert a lateral force on the spring 34 and compress the spring 34, as shown in FIG. Figure 2B The spring 34 applies an opposing biasing force (also referred to as "spring force") which depends on the spring constant.

[0060] By choosing an appropriate spring constant k, the opposing force F r The magnitude of the expansion force F e For example, a spring with a higher spring constant (and higher stiffness) corresponds to a higher ratio, and a spring with a lower spring constant corresponds to a lower ratio.

[0061] It should be noted that embodiments are not limited to the number and location of the mechanical linkages described herein. For example, the pressure compensation device may include one linkage on one side of the pressure plate 22. In addition, there may be more than one linkage mechanism 24 arranged along the y-direction.

[0062] Figure 3 and Figure 4 Aspects of a pressure management system as described herein are depicted, as well as aspects of a conventional system. Figure 5 A comparison between the characteristics of the embodiments described herein and a conventional system is also shown.

[0063] exist Figure 3 Schematically illustrates aspects of the battery cell 14 in conjunction with the mechanical linkage 24 and the transverse spring 34. For comparison, Figure 4 An example of a conventional system is shown in , which includes a vertically oriented spring 40 having a fixed end 42 attached to the housing 16 and a movable end 44 that exerts a vertical spring force on the battery cell 14. The transverse spring 34 and the spring 40 have the same spring constant.

[0064] exist Figure 3 and Figure 4In FIG. 1 , when the battery cell is at 100% state of charge (SOC) and fully expanded, a distance d is defined between the surface S1 of the battery cell 14 and the upper surface S2 of the housing 16. As the SOC decreases, the surface of the battery cell recedes, increasing the total distance between the battery cell surface S1 and the upper surface S2 by a distance Δd. At 100% SOC, and as the SOC decreases, Δd decreases toward zero.

[0065] Figure 5 A graph 50 of force F as a function of Δd is shown. In graph 50, Δd is at a maximum at the origin of the graph and decreases to zero as the battery cell 14 expands. Curve 52 shows the spring force of the vertical spring 40, which increases linearly as a function of Δd. Point 54 represents the balance between the spring force and the expansion force at 0% SOC, and point 56 represents the balance at 100% SOC.

[0066] Figure 5 Also included is a curve 58 representing the spring force of the spring 34 from an embodiment of the pressure management system 20. Point 60 represents the balance between the spring force and the expansion force at 0% SOC, and point 62 represents the balance at 100% SOC. The shape of the curve is affected by the spring constant and the design of the linkage mechanism.

[0067] Thus, as shown, due to the horizontal orientation of the spring 34 and the mechanical linkage 24, the pressure management system 20 can effectively maintain a constant pressure with a relatively small volume.

[0068] Figures 6A-6C is a force diagram depicting various aspects of force transfer using the mechanical linkage 24 and a biasing member such as a spring 34 . Figures 6A-6C Aspects of calculating forces and selecting spring characteristics to achieve the desired opposing forces are also shown.

[0069] In these figures, l1 is the length from point P1 to point P0 in the x-direction, l2 is the length from point P0 to point P2, and l3 is the length from point P2 to point P3. Pivoting member 26 defines an angle θ1 relative to the x-axis (or the lateral movement direction of end 30), and connecting member 28 defines an angle θ3 relative to the x-axis.

[0070] like Fig. 6A As shown, when force F1 (expansion force) is applied vertically (in the z-direction or parallel to the expansion direction) to pressure plate 22, pivot member 26 rotates about pivot point P0, thereby generating force F2 on connecting member 28, which in turn causes connecting member 28 to move in the x-direction and generate lateral force F3.

[0071] like Figure 6B As shown, the connecting member 28 pushes the spring 34, which causes the spring 34 to apply an opposing spring force f s. Spring force f s Proportional to distance d3, which is the lateral distance point P3 moves due to the expansion force. Spring 34 has a spring constant k, and a spring force f s is k multiplied by d3(f s =k*d3)

[0072] When the linkage mechanism 24 is in a stable state condition, the linkage mechanism 24 does not move. The pivot member 26 and the connecting member 28 can be considered as a rigid body with a fulcrum at point P0, such as Figure 6C As shown. In this case, the linkage mechanism 24 applies a force F4. The force F4 has a normal component F4 N , which represents the reverse force applied to the battery cell 14.

[0073] Under steady state conditions, the total torque is zero and can therefore be expressed as:

[0074] l1F1+l4F4=0,

[0075] Where l4 is the length from point P0 to P3 ( Figure 6C ).therefore,

[0076]

[0077] Normal component F4 N , i.e. the opposing force, can be calculated based on the following formula:

[0078]

[0079] The length l4 is the sum of d3 and the spring force f s Thus, length l4 and angle θ3 are functions of k. Thus, k can be selected to calibrate the pressure management system 20 and produce a reaction force with a desired proportion of the expansion force.

[0080] In addition to the spring constant k, other aspects of the pressure management system 20 may be selected or designed to control the opposing force F r For example, the lengths of the pivot member 26 and the connecting member 28 and the locations of the points P0 and P1 may be varied to affect the opposing forces.

[0081] In some cases, the expansion of one or more battery cells in the battery assembly is non-uniform along the battery cell (e.g., non-uniform along the x-axis). In this case, the opposing force F generated by the mechanical linkage 24 rThe pressure plate 22 is not uniform, which may result in uneven pressure distribution in the battery cells. Therefore, in an embodiment, the pressure plate 22 is allowed to tilt or change orientation in response to uneven or uneven expansion. This allows the pressure plate 22 to adjust to the non-uniform expansion, which can reduce the possibility of damaging the battery cells, and allows the opposing force applied via the pressure plate 22 to be effectively controlled to compensate for the uneven internal pressure.

[0082] For example, in Figure 2A and Figure 2B In the embodiment of FIG. 1 , the pressure plate 22 has a fixed orientation in which the lower surface 23 facing the battery cell 14 is orthogonal to the z-axis and / or the direction of the expansion force. If the local expansion force F on one side of the plate 22 e The local expansion force F on the other side of the plate 22 is different from the local expansion force F on the other side of the plate 22. e , then the reaction force F applied by the mechanical linkage device 24 r Unbalanced, which can lead to uneven pressure.

[0083] Fig. 7A and Figure 7B An embodiment of a pressure management system is depicted that is configured to apply a non-uniform opposing force in response to a non-uniform expansion force. In this embodiment, the pressure plate 22 is attached to or coupled with a tilt mechanism or tilt assembly that allows the orientation of the pressure plate 22 to change in response to different expansion conditions.

[0084] As shown, the tilt mechanism can be a set of wheels 25 attached to the ends of the pressure plate 22 and sized so that each wheel 25 engages a side wall of the housing 16 when installed. For example, a first wheel 25a supports the pressure plate 22 at a first side, and a second wheel 25b supports the pressure plate 22 at a second side. The mechanical linkage 24 at the first side is represented as linkage 24a, and the mechanical linkage 24 at the second side is represented as linkage 24b.

[0085] It should be noted that embodiments are not limited to a particular type, number, and location of components that allow orientation changes. The tilting mechanism may be any suitable mechanism or assembly that allows the pressure plate 22 to tilt. Examples include components that can slide along the sidewalls (e.g., a non-rotating cylinder or block, optionally including or made of a material that provides reduced surface roughness).

[0086] Fig. 7A FIG. 2 shows the pressure management system in an initial or default state. In this state, the pressure plate 22 is at least substantially normal to the expansion force F edirection (i.e., surface 23 is normal to the z-axis) and / or sidewalls. In this state, any force applied by the battery cell 14 is counteracted by the opposing force applied by the pressure plate 22. Note that the initial state can be characterized by any desired orientation, such as an initial tilted state.

[0087] Figure 7B An example of the state of the pressure management system when the battery cell 14 has expanded is shown. In this example, the expansion of the battery cell is uneven, resulting in uneven or unbalanced expansion forces F e As shown, the local expansion force on the side of the mechanical linkage 24a is less than the local expansion force on the side of the linkage 24b. When each linkage and the associated spring 34 apply a proportional opposing force F r When the local reaction force F at the linkage 24a r Less than the local reverse force F at the linkage 24b r .

[0088] exist Fig. 7A and Figure 7B In the embodiment, the reverse force F r Balanced expansion force F e However, there may still be an imbalance in the pressure of the battery cells 14. In order to maintain a balanced pressure (i.e., the same or similar pressure along the length of the battery 14), the spring force f applied by either or both springs 34 may be adjusted. s , so that the pressure plate 22 applies an opposing force so that the internal pressure of the battery cell 14 is uniform or balanced.

[0089] Fig. 8A and 8B An embodiment of the pressure management system 20 is depicted that includes a biasing member adjustment system 80. The biasing member adjustment system 80 may be used to control the opposing force F r ratio to compensate for the imbalance.

[0090] The adjustment system 80 includes an adjustment device, referred to as a spring adjuster 82. The spring adjuster 82 is coupled to the spring 34 and is controllable to increase or decrease spring compression, thereby controlling the spring force f s (ie, the amount of spring force in response to a given amount of lateral movement).

[0091] In an embodiment, the spring adjuster 82 includes a fixed pinion 84 coupled to at least one linear gear or rack 86 (or other linear actuator). Each linear gear 86 is attached to or otherwise engageable with a corresponding spring 34 to adjust the spring force f s For example, each linear gear 86 is attached at its end to an interface member 88 (eg, a plate or disk) that engages the spring 34 .

[0092] Pinion 84 is coupled to an actuator 90, such as a low power motor, which is operable to rotate pinion 84 to move linear gear 86 and compress or decompress spring 34. Actuator 90 may be controlled manually by an operator, or via controller 92 or other processing device.

[0093] Fig. 8A 1 shows a state where the battery cell 14 has expanded and exerts an uneven expansion force on the pressure plate 22. Although the forces on the pressure plate 22 are balanced, the local forces exerted by the battery cell 14 are different. As shown in the figure, the local expansion force F on the linkage 24b side is e Greater than the local expansion force F on the linkage 24a side e This results in a greater pressure in the area below the linkage 24b.

[0094] To balance the pressure, the spring adjuster 82 can be controlled to change the spring force f of either or both springs 34 as needed. s For example, in Fig. 8A , the spring adjuster 82 is in a default state, wherein the distance from the center of the spring adjuster (illustrated by the center axis a) to one of the springs 34 (denoted as spring 34a) is the same as the distance from the center to another of the springs 34 (denoted as spring 34b). Due to the uneven expansion of the battery cell 14, the spring force applied by the spring 34a and the resulting opposing force are less than the spring force and the associated opposing force from the spring 34b.

[0095] The spring adjuster 82 can be controlled by rotating the pinion 84 to laterally move the linear gear 86 and adjust the spring force f of the springs 34a and / or 34b. s To balance the pressure. Figure 8B As shown, pinion 84 has rotated clockwise, which moves linear gear 86 toward linkage 24a to further compress spring 34a and increase the local opposing force F r This rotation also serves to reduce the compression of spring 34b and correspondingly reduce its local spring force F r By adjusting the biasing system in this manner, the expansion forces are equalized (ie, the local expansion force F at the linkage 24a is e At least substantially related to the local expansion force F at the linkage 24b e same).

[0096] The embodiments are not limited to Fig. 8A and Figure 8BThe configuration shown in . Embodiments may include multiple spring force adjusters controlled synchronously by a single motor. In other embodiments, multiple independent spring force adjusters are provided, wherein each spring force adjuster is independently controlled.

[0097] Fig.9A and 9B An example is shown where the bias adjustment system 80 includes two independently controllable spring adjusters 82a and 82b. Each spring adjuster 82 is coupled to a different spring or biasing device and has its own motor. Fig.9A The biasing system is shown in a first state, wherein the compression on the spring 34 is relatively low, and Fig. 9B The state where both spring adjusters 82a and 82b are actuated to compress their respective springs is shown. Since each spring adjuster is independently controllable, different amounts of compression can be applied (e.g., controlling spring adjusters 82a and 82b so that one of the springs 34 has a different compression than the opposing spring 34). In this way, the opposing forces on each side of the pressure plate 22 can be adjusted as needed to balance the pressure in the battery cell 14.

[0098] Control of the bias adjustment system 80 can be performed in various ways to compensate for uneven or unbalanced pressures. For example, the controller 92 is configured to control the spring adjuster 82 based on pressure measurements, force measurements, or any other measurements related to pressure (e.g., temperature). Such measurements can be performed at various locations.

[0099] Fig.10 One embodiment of a pressure management system is shown that includes a potentiometer at each end of pressure plate 22. For example, potentiometer 100a is disposed proximate wheel 25a so that the vertical position of wheel 25a (e.g., position along the z-axis and / or along the sidewall of housing 16) can be measured. Potentiometer 100b is similarly disposed proximate wheel 25b. Controller 92 detects the signal from each potentiometer and determines if there is a difference between the positions of the wheels. If an imbalance is detected (e.g., a difference above zero or above another threshold), controller 92 operates actuator 90 (see Fig. 8A ) to adjust spring 34a and / or spring 34b (ie, compress or decompress) until a balanced state is detected.

[0100] Fig.11 An alternative embodiment is shown. In this embodiment, the measurement is made by a pressure sensor 102 disposed at the surface 23 or disposed on the surface of the battery cell 14. For example, pressure sensors 102a and 102b are disposed at locations on opposite sides of the pressure plate 22, and the controller 92 compares the pressure difference and controls the spring adjuster 82 accordingly.

[0101] Fig.12 An embodiment of a method 120 of managing pressure of a battery assembly is shown. Aspects of the method 120, such as adjustment of a biasing system, may be performed by one or more processors.

[0102] Method 120 includes a number of steps or phases represented by blocks 121-123. Method 120 is not limited to the number or order of steps therein, as some steps represented by blocks 121-123 may be performed in a different order than described below, or fewer than all of the steps may be performed.

[0103] For the purpose of illustration, Figure 1 The battery cell 10 shown in FIG. Figure 2A and 2B Aspects of the method 120 are discussed with reference to the pressure management system 20 shown in FIG. The method 120 is not limited thereto and may be used with any type of battery cell and any system having a force-opposing linkage as described herein.

[0104] At block 121, a battery assembly is assembled or manufactured. The battery assembly may be a battery module having one or more battery cells, such as module 12. Such a battery may be a lithium metal-type pouch cell or any other battery that is subject to swelling. The manufacture of the battery assembly includes setting up a pressure management system, such as Figure 2A and Figure 2B stress management system.

[0105] At box 122, the battery assembly is operated. For example, the battery module 12 is a battery pack for a vehicle and provides power to one or more electric motors of the vehicle.

[0106] At box 123, the pressure management system controls the pressure of one or more battery cells of the battery assembly when the battery cell expands during operation (or between operations). The control includes applying a proportional opposing force in a direction toward the battery cell to compensate for the expansion force and maintain a desired pressure or pressure range. For example, when the battery cell 14 expands, the mechanical linkage 24 and the spring 34 redirect a portion of the expansion force into an opposing force.

[0107] In one embodiment, the pressure management system is actively controlled to compensate for pressure or force imbalances and maintain a constant or balanced pressure in the battery cells. For example, the controller 92 monitors the pressure continuously or periodically (e.g., by sampling a potentiometer or pressure sensor), or in response to a user request. If an imbalance is detected, the controller 92 automatically adjusts the springs 34a and / or 34b as needed to balance the pressure.

[0108] As described herein, a pressure management system may be coupled to or be a part of a vehicle battery system. Fig.13 An embodiment of a motor vehicle 110 is shown, which includes a body 112. The vehicle 110 can be an internal combustion engine vehicle, an electric vehicle (EV), or a hybrid electric vehicle (HEV). In an example, the vehicle 110 is a hybrid or electric vehicle having an electric motor 114. A battery system 116 is electrically connected to the motor 114 and / or other components, such as vehicle electronics. The battery system 116 includes one or more modules 12, and each module 12 defines a high-voltage battery pack or is part of a high-voltage battery pack.

[0109] The vehicle 110 also includes one or more processing devices, such as a controller 118. The controller 118 may perform various functions, such as controlling conversion devices (e.g., one or more inverters and / or one or more direct current (DC)-DC converters), controlling components of a battery management system (e.g., spring adjuster 82), and / or monitoring the motor 114 and / or the battery system 116, among others. The controller 118 may include processing circuitry that may include an application specific integrated circuit (ASIC), electronic circuitry, a processor (shared, dedicated, or group) and memory that executes one or more software or firmware programs, combinational logic circuitry, and / or other suitable components that provide the described functionality. The controller 118 may include a non-transitory computer-readable medium storing instructions that, when processed by one or more processors of the controller 118, implement methods for operating vehicle components and systems as desired.

[0110] Fig.14 Aspects of an embodiment of a computer system 140 are shown that can perform various aspects of the embodiments described herein. The computer system 140 includes at least one processing device 142, which typically includes one or more processors for performing various aspects of the image acquisition and analysis methods described herein.

[0111] Components of computer system 140 include a processing device 142 (such as one or more processors or processing units), memory 144, and a bus 146 that couples various system components including system memory 144 to processing device 142. System memory 144 may be a non-transitory computer-readable medium and may include various computer system-readable media. Such media may be any available media that is accessible to processing device 142 and includes both volatile and non-volatile media and removable and non-removable media.

[0112] For example, system memory 144 includes nonvolatile memory 148, such as a hard drive, and may also include volatile memory 150, such as random access memory (RAM) and / or cache memory. Computer system 140 may also include other removable / non-removable, volatile / nonvolatile computer system storage media.

[0113] The system memory 144 may include at least one program product having a set (e.g., at least one) of program modules configured to perform the functions of the embodiments described herein. For example, the system memory 144 stores various program modules that generally perform the functions and / or methods of the embodiments described herein. One or more modules 152 may be included to perform functions related to monitoring the battery system. An image analysis module 154 may be included to control aspects of pressure management, such as controlling an actuator of a spring adjuster as described herein. The system 140 is not limited thereto, as other modules may be included. As used herein, the term "module" refers to a processing circuit, which may include an application specific integrated circuit (ASIC), an electronic circuit, a processor (shared, dedicated, or group) and memory that executes one or more software or firmware programs, a combinational logic circuit, and / or other suitable components that provide the described functions.

[0114] Processing device 142 may also communicate with one or more external devices 156, such as a keyboard, pointing device, and / or any device that enables processing device 142 to communicate with one or more other computing devices (e.g., a network card, a modem, etc.). Communication with various devices may occur via input / output (I / O) interfaces 164 and 165.

[0115] The processing device 142 may also communicate with one or more networks 166, such as a local area network (LAN), a general wide area network (WAN), a bus network, and / or a public network (e.g., the Internet) via a network adapter 168. It should be appreciated that, although not shown, other hardware and / or software components may be used in conjunction with the computer system 40. Examples include, but are not limited to, microcode, device drivers, redundant processing units, external disk drive arrays, RAID systems, and data archival storage systems, among others.

[0116] 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.

[0117] 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.

[0118] Unless otherwise indicated herein, all test standards are the most current standards in effect as of the filing date of this application or, if priority is claimed, the filing date of the earliest priority application in which the test standards appear.

[0119] 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 invention belongs.

[0120] 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 stress management system, comprising: a pressure plate configured to be disposed at an initial position relative to a battery cell disposed in a housing, the initial position comprising a first orientation wherein expansion of the battery cell causes an expansion force to be applied to the pressure plate; a tilt assembly configured to allow the pressure panel to change from the first orientation to a second orientation based on the expansion force non-uniformity; a mechanical linkage attached to the pressure plate, the mechanical linkage configured to move laterally in response to the expansion force and to convert the expansion force into a reaction force opposing the expansion force; as well as a biasing system comprising a biasing member configured to resist lateral movement of the mechanical linkage, the biasing system configured to apply a biasing force in a direction opposite to the direction of the lateral movement, the biasing force causing the mechanical linkage to apply the reaction force as a selected proportion of the expansion force, wherein the biasing system is controllable to vary the biasing force and the reaction force based on the non-uniform expansion force to balance the internal pressure of the battery cell.

2. The pressure management system according to claim 1, wherein: When the pressure panel is in the first orientation, a surface of the pressure panel defines a plane that is normal to the direction of the expansion force, and when the pressure panel is in the second orientation, the surface defines an angle relative to the plane.

3. The pressure management system according to claim 1, wherein: The tilt assembly includes a wheel attached to an end of the pressure plate, the wheel being configured to engage and rotate along a side wall of the housing.

4. The pressure management system according to claim 1, wherein: The biasing member has a spring constant selected such that the biasing force causes the reaction force to be a selected proportion of the expansion force.

5. The pressure management system according to claim 1, wherein: The biasing system includes a biasing control connected to the pressure plate, the biasing control being configured to be operated to adjust a biasing force of the biasing member.

6. The pressure management system according to claim 5, wherein: The bias control device is configured to limit lateral movement of the mechanical linkage device and direct a portion of the lateral force generated by the mechanical linkage device toward the battery cell based on a reaction force generated by the bias control device.

7. The pressure management system according to claim 6, wherein: The biasing member is a spring having a first end configured to be coupled to the mechanical linkage and a second end connected to the biasing control.

8. The pressure management system according to claim 5, wherein: The biasing system includes a set of sensors configured to measure parameters related to the internal pressure and a controller configured to estimate a pressure imbalance based on the measured parameters and control the biasing control device to balance the internal pressure.

9. The pressure management system according to claim 5, wherein: The bias control device includes a pinion gear coupled to a linear gear, the pinion gear being connected to an actuator configured to rotate the pinion gear to adjust the bias force.

10. A method for controlling pressure of a battery cell, comprising: receiving an expansion force at a pressure plate disposed at an initial position relative to the battery cell, the battery cell being disposed in a housing, the initial position comprising a first orientation, the expansion force being generated by expansion of the battery cell, the pressure plate being coupled to a tilt assembly, the tilt assembly being configured to allow the pressure plate to change from the first orientation to a second orientation based on the expansion force being non-uniform; as well as Managing the pressure of the battery cell by a pressure management system including a mechanical linkage attached to the pressure plate and a biasing system, wherein managing the pressure includes: converting the expansion force into a reaction force based on lateral movement of the mechanical linkage, the reaction force being configured to oppose the expansion force; controlling the reaction force based on resisting the lateral movement of the mechanical linkage by a biasing member of the biasing system, the biasing system applying a biasing force in a direction opposite to the direction of the lateral movement, the biasing force causing the mechanical linkage to apply the reaction force as a selected proportion of the expansion force; and Based on the non-uniform expansion force, the biasing force and the reaction force are adjusted to balance the internal pressure of the battery cell.

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