Electrolyte fluid metering device for lithium cells

Abstract

A battery system includes at least one lithium cell with an electrolyte having at least one polymer which is configured to be impregnated with an electrolyte fluid. In order to increase the capacity, the life and the safety of the battery system, the battery system further includes at least one electrolyte fluid metering device, by which at least one component of the electrolyte fluid can be supplied to the lithium cell and/or by which electrolyte fluid can be discharged from the lithium cell.

Claims

1. A battery system, comprising: at least one lithium cell with an electrolyte, the electrolyte including at least one polymer configured to be impregnated with an electrolyte fluid; and at least one electrolyte fluid metering device including a control device electrically connected to the at least one lithium cell, a reservoir fluidically connected to the at least one lithium cell and containing at least a portion of the electrolyte fluid, and a movable wall located within the reservoir, the control device configured to generate an electronic supply signal configured to cause the movable wall to move within the reservoir to supply the electrolyte fluid into the at least one lithium cell from the reservoir and to generate an electronic discharge signal configured to cause the movable wall to move within the reservoir to discharge the electrolyte fluid from the at least one lithium cell into the reservoir.

2. The battery system as claimed in claim 1, further comprising: a sensor electrically connected to the control device and operatively connected to the at least one lithium cell, wherein the electrolyte fluid metering device is configured to regulate automatically an amount of the at least one component of the electrolyte fluid in the at least one lithium cell based on at least one of a voltage, a current, and a temperature of the at least one lithium cell as sensed by the sensor.

3. The battery system as claimed in claim 1, wherein: the at least one lithium cell includes an anode, a cathode and a separator arranged between the anode and the cathode, and the at least one lithium cell includes at least one interface fluidically connected to the separator, the metering device configured to supply and to discharge the at least one component of the electrolyte fluid through the interface.

4. The battery system as claimed in claim 1, wherein the electrolyte fluid metering device has at least one interface fluidically connected to the separator for filling the electrolyte fluid component reservoir with at least one component of the electrolyte fluid and for removing at least one component of the electrolyte fluid from the electrolyte fluid component reservoir.

5. The battery system as claimed in claim 1, further comprising at least one measuring device.

6. The battery system as claimed in claim 1, wherein: the control device is configured to activate the electrolyte fluid metering device to supply electrolyte fluid to the lithium cell from the reservoir when an internal cell resistance is higher than a predetermined upper limit value, the control device is configured to activate the electrolyte fluid metering device to discharge electrolyte fluid from the lithium cell to the reservoir when the internal cell resistance is lower than a predetermined lower limit value, and the control device is configured to not activate the electrolyte fluid metering device to supply or discharge electrolyte fluid to or from the lithium cell when the internal cell resistance corresponds to a predetermined limit value or lies within a range that extends from the lower limit value to the upper limit value.

7. The battery system as claimed in claim 1, wherein an amount of electrolyte fluid to be supplied or to be discharged is proportional to a difference between an internal cell resistance and a corresponding limit value.

8. An electrolyte fluid metering device for a battery system, the electrolyte fluid metering device comprising: at least one electrolyte fluid component reservoir including a movable wall configured to vary a volume of the electrolyte fluid component reservoir; at least one measuring device operably connected to the battery system and configured to generate a measurement signal; and a control device electrically connected to the at least one measuring device, the control device configured to cause the moveable wall to move relative to the reservoir to supply electrolyte fluid from the reservoir into the battery system based on the measurement signal and to cause the movable wall to move relative to the reservoir to discharge electrolyte fluid from the battery system into the reservoir based on the measurement signal.

9. The electrolyte fluid metering device as claimed in claim 8, further comprising at least one interface fluidically connected to the separator for filling the electrolyte fluid component reservoir with at least one electrolyte fluid component and for removing at least one electrolyte fluid component from the electrolyte fluid component reservoir.

10. A method for operating a battery system, comprising: ascertaining an internal cell resistance of a lithium cell; determining whether the internal cell resistance ascertained lies above a predetermined upper limit value or below a predetermined lower limit value; supplying electrolyte fluid to the lithium cell from a reservoir fluidically coupled to the lithium cell when the internal cell resistance ascertained is higher than the predetermined upper limit value by moving a movable wall located within the reservoir in a first direction to supply electrolyte fluid from the reservoir into the lithium cell; and removing electrolyte fluid from the lithium cell when the internal cell resistance ascertained is lower than the predetermined lower limit value by moving the movable wall in a second direction to discharge electrolyte fluid from the lithium cell into the reservoir.

11. The battery system as claimed in claim 1, wherein the battery system is included in a vehicle.

12. The battery system as claimed in claim 2, wherein the electrolyte fluid metering device is configured to regulate an amount of the electrolyte fluid in the at least one lithium cell.

13. The battery system as claimed in claim 2, wherein the electrolyte fluid metering device is configured to regulate the amount of the at least one electrolyte fluid component in the at least one lithium cell automatically.

14. The battery system as claimed in claim 1, wherein a position of the movable wall of the electrolyte fluid metering device is variable in proportion to a difference between an internal cell resistance and a corresponding limit value.

15. The battery system as claimed in claim 7, wherein a position of the movable wall of the electrolyte fluid metering device is variable in proportion to the difference between the internal cell resistance and the corresponding limit value.

16. The electrolyte fluid metering device as claimed in claim 8, wherein the electrolyte fluid metering device is included in a vehicle.

17. The method as claimed in claim 10, wherein the method is carried out by a vehicle.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further advantages and advantageous refinements of the subjects according to the disclosure are illustrated by the drawing and explained in the description that follows. It should be noted that the drawing is only of a descriptive character and is not intended to restrict the disclosure in any form. In the drawing:

(2) The FIGURE shows a schematic representation of an embodiment of a battery system according to the disclosure, an electrolyte fluid metering device according to the disclosure and a lithium cell according to the disclosure.

DETAILED DESCRIPTION

(3) The FIGURE shows a battery system 10, which comprises a lithium cell 100, which comprises an anode 11, a cathode 12, a separator 13 arranged in between and also a gel-like electrolyte (not represented) of a polymer impregnated with an electrolyte fluid. For the electrical contacting of the anode 11 and cathode 12, the lithium cell 100 also has an anodic current collector 18 and a cathodic current collector 19.

(4) The FIGURE illustrates that the battery system also comprises an electrolyte fluid metering device 14, which is configured in the manner of a syringe and has an electrolyte fluid component reservoir 14a, the volume of which can be varied by a movable wall 14b.

(5) The FIGURE illustrates that a fluid line which extends from the electrolyte fluid metering device 14 and by way of which electrolyte fluid can be supplied to or discharged from the lithium cell 100 by the electrolyte fluid metering device 14 enters the lithium cell 100 in the region of the separator 13. In this way it is advantageously possible to control, in particular automatically, the amount of electrolyte fluid in the lithium cell 100 by the electrolyte fluid metering device 14.

(6) The FIGURE shows that the battery system also comprises an internal cell temperature measuring device 15, a cell voltage measuring device 16 and a cell current measuring device 17, which are respectively connected in signaling terms to the electrolyte fluid metering device 14. The dashed lines illustrate that the signaling connections are not necessarily formed by cables, but may also be cableless. In particular, the internal cell temperature measuring device 15, the cell voltage measuring device 16 and the cell current measuring device 17 are connected to a control device (not represented) integrated in the electrolyte fluid metering device 14.

(7) The control device can ascertain from the cell voltage measured by the cell voltage measuring device 16 and the current measured by the cell current measuring device 17 the internal cell resistance, which suggests whether electrolyte fluid should possibly be supplied or removed. Since the internal cell resistance is temperature-dependent, the internal cell temperature measured by the internal cell temperature measuring device 15 may additionally be included, in order to determine a temperature-corrected internal cell resistance and to control a supply or removal of electrolyte fluid on the basis of this.

(8) In dependence on the internal cell resistance, possibly while taking the internal cell temperature into account, the control device can control the electrolyte fluid metering device 14, in particular the position of the movable wall 14b of the electrolyte fluid component reservoir 14a.

(9) The control may in this case take place in particular in such a way that, if the internal cell resistance at the temperature at the time is higher than a predetermined limit value, electrolyte fluid is supplied to the lithium cell 100 and, if the internal cell resistance ascertained at the temperature at the time is lower than the predetermined limit value, electrolyte fluid is removed from the lithium cell 100.

(10) Since the supply and discharge of electrolyte fluid can in turn influence the measuring parameters measured later, such as the cell voltage, current and internal cell temperature, this procedure may possibly also be referred to as feedback control, and the control device referred to as a feedback control device.

(11) It is thus advantageously possible overall for the amount of electrolyte fluid within the gel-polymer electrolyte to be automatically controlled or regulated in both directions, in particular in dependence on the current, voltage and temperature.