US-20260128356-A1 - Battery Cell with Constant Compression Force

Abstract

Aspects of the disclosure include battery cells with constant compression force mechanisms. An exemplary vehicle includes an electric motor and a battery pack electrically coupled to the electric motor. The battery pack includes a plurality of battery cells and a constant force mechanism (CFM) coupled to a battery cell. The CFM includes a first vertical spring, a second vertical spring, a horizontal spring, and a plurality of rigid links. A centerline-to-centerline distance between the first vertical spring and the second vertical spring is equal to a free length of the horizontal spring. A first spring constant of the first vertical spring and a second spring constant of the second vertical spring are the same, and the first spring constant and the second spring constant are each half a third spring constant of the horizontal spring.

Inventors

• Shashank RAMESH
• Chinmaya Patil
• Madhusudan Raghavan
• Derek Frei Lahr
• Jun-Mo Kang
• Insu Chang

Assignees

• GM Global Technology Operations LLC

Dates

Publication Date

20260507

Application Date

20241107

Claims (20)

1. 1 . A vehicle comprising: an electric motor; a battery pack electrically coupled to the electric motor, the battery pack comprising a plurality of battery cells; and a constant force mechanism coupled to at least one battery cell of the plurality of battery cells, the constant force mechanism comprising: a first vertical spring; a second vertical spring; a horizontal spring; and a plurality of rigid links; wherein a centerline-to-centerline distance between the first vertical spring and the second vertical spring is equal to a free length of the horizontal spring, the free length comprising a length of the horizontal spring when free of an external load; and wherein a first spring constant of the first vertical spring and a second spring constant of the second vertical spring are the same, and the first spring constant and the second spring constant are each half a third spring constant of the horizontal spring.
2. 2 . The vehicle of claim 1 , wherein the plurality of rigid links comprises: a first rigid link coupled to a first end of the first vertical spring and a first end of the horizontal spring; and a second rigid link coupled to a first end of the second vertical spring and a second end of the horizontal spring.
3. 3 . The vehicle of claim 2 , wherein the plurality of rigid links comprises: a third rigid link coupled to a second end of the first vertical spring and the first end of the horizontal spring; and a fourth rigid link coupled to a second end of the second vertical spring and the second end of the horizontal spring.
4. 4 . The vehicle of claim 3 , further comprising: a contact plate in direct contact with a first battery cell of the plurality of battery cells; wherein the first end of the first vertical spring and the first end of the second vertical spring are coupled to the contact plate.
5. 5 . The vehicle of claim 4 , further comprising: a base plate; wherein the second end of the first vertical spring and the second end of the second vertical spring are coupled to the base plate.
6. 6 . The vehicle of claim 2 , wherein the plurality of rigid links comprises: a third rigid link coupled to the first end of the horizontal spring; and a fourth rigid link coupled to the second end of the horizontal spring.
7. 7 . The vehicle of claim 6 , further comprising: a contact plate in direct contact with a first battery cell of the plurality of battery cells; and a base plate coupled to the third rigid link and the fourth rigid link.
8. 8 . The vehicle of claim 7 , further comprising a force adjusting plate; wherein a second end of the first vertical spring and a second end of the second vertical spring are coupled to the force adjusting plate.
9. 9 . The vehicle of claim 8 , further comprising an actuator coupled to the force adjusting plate, the actuator configured to change a distance between the force adjusting plate and the first battery cell.
10. 10 . The vehicle of claim 9 , further comprising a controller coupled to the actuator, the controller configured to direct the actuator to change the distance between the force adjusting plate and the first battery cell to adjust an amount of force applied against the first battery cell.
11. 11 . A system comprising: a battery pack comprising a plurality of battery cells; and a constant force mechanism coupled to at least one battery cell of the plurality of battery cells, the constant force mechanism comprising: a first vertical spring; a second vertical spring; a horizontal spring; and a plurality of rigid links; wherein a centerline-to-centerline distance between the first vertical spring and the second vertical spring is equal to a free length of the horizontal spring, the free length comprising a length of the horizontal spring when free of an external load; and wherein a first spring constant of the first vertical spring and a second spring constant of the second vertical spring are the same, and the first spring constant and the second spring constant are each half a third spring constant of the horizontal spring.
12. 12 . The system of claim 11 , further comprising: a piston coupled to the constant force mechanism; and a ribbon positioned adjacent to the at least one battery cell; wherein displacing the piston adjusts a volume of fluid in the ribbon.
13. 13 . The system of claim 12 , wherein the system further comprises: a force adjusting plate; and an actuator coupled to the force adjusting plate, the actuator configured to change a distance between the force adjusting plate and the piston.
14. 14 . The system of claim 13 , wherein the system further comprises: a pressure sensor; and a controller coupled to the actuator, the controller configured to direct the actuator to change the distance between the force adjusting plate and the piston responsive to a measurement of the pressure sensor.
15. 15 . The system of claim 14 , wherein the system further comprises a battery cell tray coupled to each battery cell of the plurality of battery cells, the battery cell tray configured to prevent cell-to-cell relative motion between the battery cells of the plurality of battery cells.
16. 16 . A method comprising: providing a battery pack comprising a plurality of battery cells; and coupling a constant force mechanism to at least one battery cell of the plurality of battery cells, the constant force mechanism comprising: a first vertical spring; a second vertical spring; a horizontal spring; and a plurality of rigid links; wherein a centerline-to-centerline distance between the first vertical spring and the second vertical spring is equal to a free length of the horizontal spring, the free length comprising a length of the horizontal spring when free of an external load; and wherein a first spring constant of the first vertical spring and a second spring constant of the second vertical spring are the same, and the first spring constant and the second spring constant are each half a third spring constant of the horizontal spring.
17. 17 . The method of claim 16 , further comprising: forming a piston coupled to the constant force mechanism; and forming a ribbon positioned adjacent to the at least one battery cell; wherein displacing the piston adjusts a volume of fluid in the ribbon.
18. 18 . The method of claim 17 , further comprising: forming a force adjusting plate; and coupling an actuator to the force adjusting plate, the actuator configured to change a distance between the force adjusting plate and the piston.
19. 19 . The method of claim 18 , further comprising: providing a pressure sensor to monitor a pressure of the fluid; and coupling a controller to the actuator, the controller configured to direct the actuator to change the distance between the force adjusting plate and the piston responsive to a measurement of the pressure sensor.
20. 20 . The method of claim 19 , further comprising forming a battery cell tray coupled to each battery cell of the plurality of battery cells, the battery cell tray configured to prevent cell-to-cell relative motion between the battery cells of the plurality of battery cells.

Description

INTRODUCTION The present disclosure relates to battery cell manufacturing, and particularly to a battery cell, module, or pack with a constant compression force mechanism. Lithium-ion batteries, also known as lithium-ion cells, are a type of rechargeable battery technology that have gained significant attention due to their relatively high energy density and long cycle life compared to other battery chemistries. The anode (negative electrode) in a lithium-ion cell is typically made of graphite, a carbon-based material that can reversibly intercalate and deintercalate lithium ions. The cathode (positive electrode) can be made of various lithium-containing compounds, such as lithium transition metal oxides (e.g., LiCoO2, LiNiMnCoO2, etc.), lithium metal phosphates (e.g., LiFePO4), or other suitable materials that can reversibly intercalate and deintercalate lithium ions. The electrodes in a lithium-ion cell are separated by an electrolyte, which is typically a lithium salt dissolved in an organic solvent, a solid polymer or solid-state electrolyte. The electrolyte acts as a medium for lithium ion transport between the anode and cathode during charge and discharge processes. Current collectors provide a conductive pathway for electrons to flow between the electrodes and an external circuit. The current collector for the anode is typically made of copper or a copper alloy, while the current collector for the cathode is typically made of aluminum or an aluminum alloy. During the discharge process, lithium ions deintercalate from the anode and migrate through the electrolyte to intercalate into the cathode material, while electrons flow through the external circuit to power a device. During charging, this process is reversed, with lithium ions being extracted from the cathode and intercalated back into the anode. SUMMARY In one exemplary embodiment a vehicle includes an electric motor and a battery pack electrically coupled to the electric motor. The battery pack includes a plurality of battery cells and a constant force mechanism (CFM) coupled to a battery cell of the plurality of battery cells. The CFM includes a first vertical spring, a second vertical spring, a horizontal spring, and a plurality of rigid links. A centerline-to-centerline distance between the first vertical spring and the second vertical spring is equal to a free length of the horizontal spring. A first spring constant of the first vertical spring and a second spring constant of the second vertical spring are the same, and the first spring constant and the second spring constant are each half a third spring constant of the horizontal spring. In addition to one or more of the features described herein, in some embodiments, the plurality of rigid links includes a first rigid link coupled to a first end of the first vertical spring and a first end of the horizontal spring and a second rigid link coupled to a first end of the second vertical spring and a second end of the horizontal spring. In some embodiments, the plurality of rigid links includes a third rigid link coupled to a second end of the first vertical spring and the first end of the horizontal spring and a fourth rigid link coupled to a second end of the second vertical spring and the second end of the horizontal spring. In some embodiments, a contact plate is in direct contact with a first battery cell of the plurality of battery cells. In some embodiments, the first end of the first vertical spring and the first end of the second vertical spring are coupled to the contact plate. In some embodiments, the CFM includes a base plate. In some embodiments, the second end of the first vertical spring and the second end of the second vertical spring are coupled to the base plate. In some embodiments, the plurality of rigid links includes a third rigid link coupled to the first end of the horizontal spring and a fourth rigid link coupled to the second end of the horizontal spring. In some embodiments, a contact plate is in direct contact with a first battery cell of the plurality of battery cells and a base plate is coupled to the third rigid link and the fourth rigid link. In some embodiments, the cfm includes a force adjusting plate. In some embodiments, a second end of the first vertical spring and a second end of the second vertical spring are coupled to the force adjusting plate. In some embodiments, an actuator is coupled to the force adjusting plate. The actuator is configured to change a distance between the force adjusting plate and the first battery cell. In some embodiments, a controller is coupled to the actuator. The controller is configured to direct the actuator to change the distance between the force adjusting plate and the first battery cell to adjust an amount of force applied against the first battery cell. In another exemplary embodiment a system includes a battery pack having a plurality of battery cells and a constant force mechanism coupled to at least one battery cell