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DE-102022208964-B4 - Process arrangement with a battery cell and method for manufacturing such a process arrangement

DE102022208964B4DE 102022208964 B4DE102022208964 B4DE 102022208964B4DE-102022208964-B4

Abstract

Process arrangement with a battery cell comprising an electrode/separator stack (1) in which anodes (A), separators (S) and cathodes (K) are stacked one above the other, wherein each anode (A) is connected to an anode cell connector (9) via an anode connector (5) and each cathode (K) is connected to a cathode cell connector (11) via a cathode connector (7), wherein the battery cell can be switched into a charge/discharge circuit (13) with its cathode cell connector (11) and with its anode cell connector (9) to carry out a charge/discharge process, and wherein the electrode/separator stack (1) can be subdivided in the stacking direction into stacked electrode pairs (E1 to E5), each of which electrode pairs (E1 to E5) consists of an anode (A), an adjacent cathode (K) and an intermediate The separator (S) consists of a process arrangement comprising a balancing control loop in which a control unit (25) is integrated, which detects the actual voltage (U1 to U5) of each electrode pair (E1 to E5) during the charging/discharging process, and wherein the actual voltages (U1 to U5) of the electrode pairs (E1 to E5) can be balanced against each other by means of the control unit (25), wherein each electrode pair (E1 to E5) is assigned an actuator (29) that can be controlled by the control unit (25), and wherein, if the actual voltage (U1 to U5) in at least one of the electrode pairs deviates from a target voltage value, the control unit (25) adjusts the charging/discharging current flow through the electrode pair (U1 to U5) via the actuator (29), i.e., increases or decreases it, in order to bring the actual voltage (U1 to U5) of the electrode pair to the target voltage value. regulating, wherein the cell arrester (9, 11) has a separate connection point for each arrester tab (5, 7) which is functionally and/or spatially independent of other connection points, and wherein in each connection point the arrester tab (5, 7) is in electrical and mechanically detachable connection with an associated cell arrester contact element (17), and wherein the conductivity between the cell arrester contact element (17) and the arrester tab (5, 7) and thus the current flow through the electrode pair (E1 to E5) can be adjusted by means of the actuator (29), characterized in that the actuator (29) has a spring element (21) which presses the cell arrester contact element (17) against the arrester tab (5, 7) with a spring force (F), and that the spring force (F) of the spring element (21) can be adjusted by means of the actuator (29). The conductivity between the cell drain contact element (17) and the drain tab (5, 7) can be varied to adjust the conductivity.

Inventors

  • Kartik Jamadar

Assignees

  • VOLKSWAGEN AKTIENGESELLSCHAFT

Dates

Publication Date
20260513
Application Date
20220830

Claims (7)

  1. Process arrangement with a battery cell comprising an electrode/separator stack (1) in which anodes (A), separators (S) and cathodes (K) are stacked one above the other, wherein each anode (A) is connected to an anode cell connector (9) via an anode connector (5) and each cathode (K) is connected to a cathode cell connector (11) via a cathode connector (7), wherein the battery cell can be switched into a charge/discharge circuit (13) with its cathode cell connector (11) and with its anode cell connector (9) to carry out a charge/discharge process, and wherein the electrode/separator stack (1) can be subdivided in the stacking direction into stacked electrode pairs (E1 to E5), each of which electrode pairs (E1 to E5) consists of an anode (A), an adjacent cathode (K) and an intermediate The separator (S) consists of a process arrangement comprising a balancing control loop in which a control unit (25) is integrated, which detects the actual voltage (U1 to U5) of each electrode pair (E1 to E5) during the charging/discharging process, and wherein the actual voltages (U1 to U5) of the electrode pairs (E1 to E5) can be balanced against each other by means of the control unit (25), wherein each electrode pair (E1 to E5) is assigned an actuator (29) that can be controlled by the control unit (25), and wherein, if the actual voltage (U1 to U5) in at least one of the electrode pairs deviates from a target voltage value, the control unit (25) adjusts the charging/discharging current flow through the electrode pair (U1 to U5) via the actuator (29), i.e., increases or decreases it, in order to bring the actual voltage (U1 to U5) of the electrode pair to the target voltage value. The cell arrester (9, 11) has a separate connection point for each arrester tab (5, 7), which is functionally and/or spatially independent of other connection points, and wherein in each connection point the arrester tab (5, 7) is in electrical and mechanically detachable connection with an associated cell arrester contact element (17), and wherein the conductivity between the cell arrester contact element (17) and the arrester tab (5, 7) and thus the current flow through the electrode pair (E1 to E5) can be adjusted by means of the actuator (29), characterized in that the actuator (29) has a spring element (21) which presses the cell arrester contact element (17) against the arrester tab (5, 7) with a spring force (F), and that the spring force (F) of the spring element (21) can be varied by means of the actuator (29) to adjust the conductivity between the cell arrester contact element (17) and the arrester tab (5, 7). (17) and drain vane (5, 7).
  2. Process arrangement with a battery cell comprising an electrode/separator stack (1) in which anodes (A), separators (S) and cathodes (K) are stacked one above the other, wherein each anode (A) is connected to an anode cell connector (9) via an anode connector (5) and each cathode (K) is connected to a cathode cell connector (11) via a cathode connector (7), wherein the battery cell can be switched into a charge/discharge circuit (13) with its cathode cell connector (11) and with its anode cell connector (9) to carry out a charge/discharge process, and wherein the electrode/separator stack (1) can be subdivided in the stacking direction into stacked electrode pairs (E1 to E5), each of which electrode pairs (E1 to E5) consists of an anode (A), an adjacent cathode (K) and an intermediate Separator (S) consists of a process arrangement comprising a balancing control loop in which a control unit (25) is integrated, which detects an actual voltage (U1 to U5) of each electrode pair (E1 to E5) during the charging/discharging process, and wherein the actual voltages (U1 to U5) of the electrode pairs (E1 to E5) can be balanced against each other by means of the control unit (25), wherein each electrode pair (E1 to E5) has an actuator that can be controlled by the control unit (25). (29) is assigned, and wherein, in the event of a deviation of the actual voltage (U1 to U5) in at least one of the electrode pairs from a target voltage value, the control unit (25) adjusts the charging/discharging current flow through the electrode pair (U1 to U5) via the actuator (29), i.e., increases or reduces it, in order to regulate the actual voltage (U1 to U5) of the electrode pair to the target voltage value, wherein the cell arrester (9, 11) has a separate connection point for each arrester tab (5, 7), which is functionally and/or spatially independent of other connection points, and wherein in each connection point the arrester tab (5, 7) is in electrical and mechanically detachable connection with an assigned cell arrester contact element (17), and wherein, by means of the actuator (29), the conductivity between the cell arrester contact element (17) and the arrester tab (5, 7) and thus the current flow through the electrode pair (E1 to E5) is adjustable, wherein the actuator (29) has an adjusting element (35) which is arranged in a contact plane between the cell arrester contact element (17) and the arrester flag (5, 7), wherein by adjusting the adjusting element (35) in the contact plane the size of a current-carrying cross-section between cell arrester contact element (17) and arrester flag (5, 7) and thus the current flow through the electrode pair (E1 to E5) is adjustable, and wherein the adjusting element (35) is adjustable between an electrically conductive position and an electrically non-conductive position.
  3. Process order according to Claim 2 , characterized in that the actuating element (35) and the cell arrester contact element (17) each have at least one conductive area (37) and at least one non-conductive area (39), and that in the electrically conductive position the actuating element (35) and the cell arrester contact element (17) are in electrical contact with each other with their conductive areas (37), and/or that in the electrically non-conductive position the conductive area (37) of the actuating element (35) is in contact with the non-conductive area (39) of the cell arrester contact element (17), so that no current flows through the electrode pair in question.
  4. Process order according to Claim 2 or 3 , characterized in that the actuating element (35) is designed as a flat profile or plate-shaped, and that the actuating element (35) is arranged to be transversely displaceable by means of linear movement within the contact plane between cell arrester contact element (17) and the arrester flag (5, 7), and that by adjusting the actuating element (35) in the contact plane the size of a current-carrying cross-section between cell arrester contact element (17) and arrester flag (5, 7) and thus the current flow through the electrode pair (E1 to E5) can be adjusted.
  5. Process order according to Claim 2 or 3 , characterized in that the actuating element (35) is a rotatably mounted actuating element (35), and that by rotating the actuating element (35) the size of a current-carrying cross-section between cell arrester contact element (17) and arrester tab (5, 7) and thus the current flow through the respective electrode pair is adjustable, and that the actuating element (35) is rotatable between an electrically conductive position and an electrically non-conductive position, and/or that the rotatable actuating element (35) has at least one conductive area (37) and one non-conductive area (39), wherein in the electrically conductive position the rotatable actuating element (35) is in electrical contact with the cell arrester contact element (17) and with the arrester tab (5, 7) so that a current flow (I) is established, or that in the electrically non-conductive position the non-conductive area (39) of the rotatable actuating element (35) is in contact with the cell current collector contact element (17) so that no current flows through the electrode pair in question.
  6. Process arrangement according to one of the preceding claims, characterized in that each of the electrode pairs (E1 to E5) together with the control unit (25) is integrated in a voltage measuring circuit (26) in which the actual voltage (U1 to U5) between the cathode (K) and the anode (A) of the electrode pair (E1 to E5) is tapped by means of measuring contacts (27), and/or that the control unit (25) calculates an average value from all actual voltages (U1 to U5) of the electrode pairs (E1 to E5) which forms the target voltage value.
  7. Method for manufacturing a process arrangement according to the previous Claims 1 until 6 with a battery cell comprising an electrode/separator stack (1) in which anodes (A), separators (S) and cathodes (K) are stacked one above the other, each anode (A) being connected to an anode cell connector (9) via an anode connector (5) and each cathode (K) being connected to a cathode cell connector (11) via a cathode connector (7), the battery cell being connectable to a charge/discharge circuit (13) via its cathode cell connector (11) and its anode cell connector (9) for carrying out a charge/discharge process, and the electrode/separator stack (1) being divisible in the stacking direction into stacked electrode pairs (E1 to E5), each electrode pair (E1 to E5) consisting of an anode (A), an adjacent cathode (K) and an intermediate separator (S) consists of a process arrangement comprising a balancing control loop in which a control unit (25) is integrated which maintains an actual voltage (U1 to U5) of each electrode pair (E1 to E5) during the charging/discharging process The process is characterized in that a first separator (S) is first placed on a storage surface, and a voltage measuring contact (27) and an insulating counter-holding plate (23) are placed together as an assembly on the storage surface, comprising a first process step in which the anode (A) is stacked on the first separator (S) and the components of the cell arrester (9) are stacked below it, wherein after placing the anode (A) a further separator (S) is stacked on the anode (A), and a second process step in which a voltage measuring contact (27), the cell arrester contact element (17) and the spring element (21) are attached together as an assembly on top of the anode (A), and wherein the first and second process steps are repeated each time a further anode is placed (A) is stacked on a separator (S), and wherein, once the electrode/separator stack (1) is completed, all subassemblies of the cell current collector (9) above and below each anode (A) are connected with a common plastic body (38) and then screwed together by means of at least one screw (40), and that the above process sequence is not only feasible on the anode side, but is also feasible on the cathode side.

Description

The invention relates to a process arrangement with a battery cell according to claim 1 or 2 and a method for manufacturing a process arrangement according to claim 7. A battery cell has an electrode/separator stack in which anodes, separators, and cathodes are stacked on top of each other. Each anode is connected to an anode cell connector via an anode connector, while each cathode is connected to a cathode cell connector via a cathode connector. The battery cell can be connected to a charge/discharge circuit via its cathode cell connector and its anode cell connector to perform a charging/discharging process. The electrode/separator stack can be subdivided into stacked electrode pairs. Each electrode pair consists of an anode, an adjacent cathode, and an intermediate separator. In a battery cell, the electrode pairs (anode, cathode, and intermediate separator) are connected in parallel. Due to this parallel connection, the electrode pairs typically exhibit the same voltage during charging and discharging, which ranges between 3 and 5 volts depending on the anode and cathode chemistry and state of charge (SOC). However, it is not guaranteed that all electrode pairs contribute equally to the overall capacity. If one electrode pair discharges more capacity or absorbs more capacity during charging, it will age faster than other electrode pairs in the electrode/separator stack. Currently, there is no way to control this, as balancing does not occur at the electrode level. If an electrode pair has a higher discharge or charge capacity, it will also lose or gain voltage more quickly (even if the electrodes are connected in parallel). If the electrode pair loses its voltage below the lower discharge voltage, there is a risk of copper dendrite formation or electrolyte leakage through holes in the copper substrate film. This means that, although the electrode pairs are connected in parallel, there is a high probability that some electrode pairs will have a different voltage than other electrode pairs connected in parallel. If one electrode pair receives a higher capacitive charge during charging, there is a risk that this electrode pair will receive a higher voltage than the higher charging voltage (even though all electrodes are connected in parallel). It is possible that the electrode pair with the higher voltage will exceed the maximum permissible voltage. This can lead to cathode rupture, the release of heat and oxygen, and ultimately thermal runaway. Cell balancing cannot prevent this problem, as it assumes that all electrode pairs in the electrode/separator stack of the respective battery cell always have the same voltage and contribute equally to the capacity. However, it is possible that electrode pairs within the cell behave differently compared to other electrode pairs. To reduce the aging of the electrode pairs and prevent them from reaching the lowest permissible discharge voltage or the highest permissible charge voltage, balancing at the electrode level is necessary. This is not possible with current battery technology. The current contribution of the individual electrode pairs in the electrode/separator stack of the battery cell is not equal. This means that some electrode pairs in the respective battery cell contribute a higher current, while other electrode pairs contribute a lower current to the current output (capacity) or current input (capacity). During discharge, electrons (i.e., the electric current) move to the respective cathode and are absorbed by the lithium ions that come from the anode via ion transfer through the separator. It cannot be guaranteed that the current flow in each cathode is the same. During discharge, electrons (current) move from the anodes to the cathodes, causing a current to flow through the electrical load in the discharge circuit. There is no way to guarantee that the current from each anode is the same. The electrode leads are welded together using state-of-the-art laser or ultrasonic welding. Thermal welding processes, such as laser welding, create a heat-affected zone that can impair the active material near the weld seam. Thermal welding also produces oxides that are less conductive than the base material, such as copper for the anode and aluminum for the cathode. Furthermore, laser welding of copper requires a high power output of more than 6 MW. This necessitates significant energy for the production of electrodes and cells. Solid-state welding, like ultrasonic welding, has the disadvantage of causing microcracks in thin films. Therefore, if this welding of the electrode can be avoided, the quality will be compromised. the connection between the cell probe and the electrode is improved. If the cell is to be subjected to a test procedure, it is tested together with all electrodes according to the prior art. Therefore, defects in a single electrode within the electrode/separator stack of the battery cell are not detected. Sometimes a small defect in an electrode