Cell monitoring system and electrochemical cell

Abstract

The invention relates to a cell monitoring system (1, 1', 1") of an electrochemical cell (2, 2', 2"), comprising a cell (2, 2', 2") designed as a wound cell (4) and at least one sensor (6), wherein the wound cell (4) is wound from two stacked electrode foils and an intermediate separator and comprises a positive terminal (2.1) and a negative terminal (2.2) at its end face, and wherein the at least one sensor (6) is integrated directly into the wound cell (4) or is arranged directly on the wound cell (4) and can be wirelessly coupled to or is coupled to an external battery management system (8).

Description

[0001] The invention relates to a cell monitoring system of an electrochemical cell (also called a galvanic cell) and an electrochemical cell with such a cell monitoring system.

[0002] From US patent 8,399,115 B2, a monitoring system for individual cells within large battery stacks used in alternative fuel vehicles is known. The monitoring of the individual cells is performed via wireless sensor networks. In one embodiment, a battery stack consisting of a plurality of cells comprises a plurality of wireless sensor nodes, each electrically connected to a corresponding cell in the plurality. Each of the wireless sensor nodes contains a sensor circuit for measuring individual performance characteristics for the cells to which the wireless sensor nodes are connected.This cell-specific performance data can then be wirelessly transmitted to an external node coupled with a vehicle battery management system configured to determine at least one of the state of charge, health status, and remaining service life data for the entire battery stack based on the performance characteristics of each cell in the battery stack.

[0003] The invention is based on the objective of providing an improved cell monitoring system for individual cells of an electrochemical energy storage device as well as an improved individual electrochemical cell.

[0004] The first problem is solved according to the invention by a cell monitoring system having the features of claim 1. The second problem is solved according to the invention by a cell having the features of claim 7.

[0005] Advantageous embodiments of the invention are the subject of the dependent claims.

[0006] The cell monitoring system according to the invention for an electrochemical cell comprises a cell designed as a wound cell and at least one sensor, wherein the wound cell is wound from two stacked electrode foils and an intermediate separator and comprises a positive pole connection and a negative pole connection at its end face, and wherein the at least one sensor is integrated directly into the wound cell or arranged directly on the wound cell and can be wirelessly coupled to or is coupled to a battery management system.

[0007] The electrochemical cell according to the invention comprises such an integrated cell monitoring system, which can be wirelessly connected to or coupled with the external battery management system. The cell is, in particular, part of an electrical energy storage device, especially a high-voltage battery, of a vehicle.

[0008] The advantages achieved with the invention consist in particular in the fact that, by integrating the at least one sensor into the cell and coupling this sensor with the external battery management system, the state of this individual cell in the electrical energy storage device, for example a cell stack or a cell pack consisting of a plurality of cells, is known, which in turn allows the battery management system to ensure safe and continuous operation of the energy storage device through appropriate control.

[0009] Furthermore, integrating the sensor into the cell enables efficient use of installation space. Complex cable harnesses are eliminated. The energy storage system, comprised of multiple such cells, exhibits increased energy density. Additionally, material requirements are reduced, resulting in cost savings since no cable routing is necessary. Moreover, the integrated sensor technology allows for improved and early detection of critical events and conditions within the cell, such as thermal runaway, particularly critical pressure, critical temperatures, or cell aging, thus preventing issues like lithium plating. This precise, direct monitoring of cell conditions helps to avoid critical conditions such as overcharging or overheating of the individual cell. This enhances the safety not only of the specific cell but also of the entire energy storage system.

[0010] Furthermore, the invention enables customized operating windows for each cell, allowing for full utilization of the cell capacity. In particular, improved monitoring and control of the respective cell (also called a battery cell) is possible, leading to more efficient use of the cell capacity, increased fast-charging capability, and a longer lifespan for the energy storage device (also called a battery). Specifically, the plating limit, i.e., the anode and cathode potential, can be precisely monitored. This allows, among other things, optimization of the charging process. Direct measurement of the potential at the anode and cathode allows for more precise control of the charging process. This, in turn, makes it possible to increase the charging rate while avoiding lithium plating: Lithium plating occurs when lithium metal is deposited on the anode, which can happen particularly during excessively fast charging.Direct monitoring helps to identify the conditions under which lithium plating occurs and allows the battery management system to adjust the charging process accordingly.

[0011] Furthermore, the performance management of the energy storage system, comprised of numerous cells with an integrated cell monitoring system, can be improved: The ability to precisely monitor the condition of each cell allows for optimization of the energy storage system's performance profile. This enables the depth of discharge (DoD) to be individually adjusted for each cell to maximize the overall performance and capacity of the energy storage system. Cell formation can be performed by the integrated sensors, leading to a reduction in production time, as formation can occur individually and even during shipping.

[0012] Additionally, a memory, particularly a data storage device, can be integrated into the cell. Integrating a memory into the cell enables the recording of sensor signals and / or production parameters, thereby improving quality assurance and traceability.

[0013] By integrating a communication unit, particularly a radio unit with an antenna, into the cell, the integrated sensor can communicate wirelessly, for example via radio, with the battery management system. For instance, the respective cell can communicate detected critical parameters and / or identified critical states and / or damage to the battery management system, thereby increasing the safety of the energy storage system. For example, integrated acceleration sensors can be provided that detect mechanical stresses on the cell and communicate these to the battery management system. This allows potential damage to be detected early and suitable measures to prevent or reduce potential damage to be generated or implemented.

[0014] Exemplary embodiments of the invention are explained in more detail below with reference to a drawing.

[0015] This shows: Fig. 1 Schematic representation of a first embodiment of a cell monitoring system, directly integrated into an electrochemical cell, Fig. 2 schematically a second embodiment of a cell monitoring system, directly integrated in an electrochemical cell, and Fig. 3 schematically a third embodiment of a cell monitoring system, directly integrated on an electrochemical cell.

[0016] Corresponding parts are marked with the same reference symbols in all figures.

[0017] Fig. Figure 1 schematically shows a first embodiment of a cell monitoring system 1, directly integrated into an electrochemical cell 2.

[0018] The electrochemical cell 2 (also called a galvanic cell) is designed as a wound cell 4, which is wound in the conventional manner from two stacked electrode foils and an intermediate separator. The electrochemical cell 2 has a cell housing 2.0.

[0019] At its front end, the electrochemical cell 2 comprises a positive terminal 2.1 and a negative terminal 2.2.

[0020] Furthermore, at least one sensor 6 is integrated into the electrochemical cell 2. Specifically, the at least one sensor 6 is directly integrated into the winding cell 4 and can be wirelessly connected to or coupled with a battery management system 8. For this purpose, a communication unit 10 (also called a transmission unit) can additionally be integrated into the electrochemical cell 2, with the communication unit 10 being signal-coupled to the sensor 6. The communication unit 10 includes an antenna 10.1. The antenna 10.1 can, for example, be located at an end face of the winding cell 4 (also called a jelly roll) or extend outside the actual winding, but still within the cell housing 2.0, in order to maximize the signal strength.

[0021] The direct measurement of cell parameters, such as cell temperature, cell pressure, cell condition or the like, using the sensors 6 integrated into the electrochemical cell 2, replaces indirect measurement methods and estimates, leading to a more accurate assessment of the condition of the electrochemical cell 2.

[0022] The electrochemical cell 2, for example configured as a coiled cell 4, is designed such that an inner cavity 4.1 is formed in which the at least one sensor 6 is arranged. The coiled cell 4 can be configured as a hollow cylinder or hollow body. The coiled cell 4 can have a round cross-section, a prismatic cross-section, or a rectangular cross-section, in particular a square cross-section. The sensor(s) 6 can be integrated, for example, in a prismatic or cylindrical electrochemical cell 2, regardless of its format.

[0023] For electrical supply, at least one sensor 6 is directly coupled to the positive terminal 2.1 and the negative terminal 2.2. In other words, the sensor 6 is directly powered by the associated electrochemical cell 2. The energy supply for the sensor(s) 6 and the communication unit 10 is thus provided autonomously by the electrochemical cell 2 itself.

[0024] The communication unit 10 is wireless, for example as a radio unit, a WLAN unit, a Bluetooth unit, or the like. Such wireless communication enables the exchange of status data between the electrochemical cell 2 and the battery management system 8 in real time, both within an energy storage device (also called a battery module, not shown) and in the entire battery, in particular a high-voltage battery (not shown).

[0025] Sensor 6 can be, for example, at least one of the following detection units: a pressure sensor, a temperature sensor, a level sensor, an accelerometer, a charge level sensor, an electrode potential sensor and / or another suitable battery parameter sensor.

[0026] Additionally, at least one resistor 12 can be integrated into the winding cell 4. Wireless manipulation of the internal state of the electrochemical cell 2, such as balancing, is achieved passively using resistors 12.

[0027] Furthermore, the resistor 12 integrated into the electrochemical cell 2 can be configured, and in particular controlled, to enable targeted temperature control of the electrochemical cell 2. This allows the performance and safety of the respective electrochemical cell 2 to be improved under various operating conditions.

[0028] Fig. Figure 1 shows an electrochemical cell 2 designed as a winding cell 4, into which the sensor(s) 6, which may be surrounded by a sensor housing 6.1, are subsequently integrated into the inner cavity 4.1, in particular by being plugged in. The sensor(s) 6 are coupled and connected to the terminals 2.1 and 2.2 via connecting lines 14 and are electrically supplied directly by the electrochemical cell 2 itself.

[0029] A sensor 6 is understood to be, in particular, an electronic sensor unit that may comprise one or more electronic sensors 6, which are, for example, integrated on a printed circuit board. The communication unit 10 may also be integrated on this printed circuit board.

[0030] Fig. Figure 2 schematically shows a second embodiment of a cell monitoring system 1', directly integrated into an electrochemical cell 2', which is designed as a wound cell 4. The sensor(s) 6 are arranged in the sensor housing 6.1, for example, centrally or surrounded by the wound cell. The sensor(s) 6 are integrated into the electrochemical cell 2', particularly the wound cell 4, during its manufacture. The two stacked electrode foils and the separator between them of the electrochemical cell 2' are wound around the sensor housing 6.1, for example. The electrochemical cell 2' with the internal sensor(s) 6 is then inserted into the cell housing 2.0. The sensor(s) 6 can be connected to the terminals 2.1 and 2.2 directly by soldering or optionally via connecting leads 14. The sensor(s) 6 are analogous to the embodiment shown in Figure 2. Fig. 1 Pressure sensors, temperature sensors, acceleration sensors, charge level sensors, or the like are used and employed. Likewise, the communication unit 10 with antenna 10.1 and / or at least one resistor 12 is integrated into this electrochemical cell 2' during its manufacture. In the manufactured state, the at least one sensor 6, the communication unit 10, and the resistor 12 form an inner core 2.3 of the electrochemical cell 2'.

[0031] Fig. Figure 3 schematically shows a third embodiment of a cell monitoring system 1", which is directly integrated into an electrochemical cell 2".

[0032] The sensor 6, located in the sensor housing 6.1, and the communication unit 10 are arranged externally directly on the electrochemical cell 2", which is designed as a wound cell 4. The sensor 6 and the communication unit 10 are connected to the poles 2.1 and 2.2 for electrical supply via connecting lines 14. The sensor 6 is wirelessly connected to the battery management system 8 via the communication unit 10. The inner cavity 4.1 of this electrochemical cell 2" can be designed as a hollow cylinder. Reference symbol list 1, 1', 1" Cell Monitoring System 2, 2', 2" electrochemical cell 2.0 Cell casing 2.1 positive terminal 2.2 negative terminal 2.3 Core 4 winding cell 4.1 Inner cavity 6 Sensor 6.1 Sensor housing 8 Battery Management System 10 Communication Unit 10.1 Antenna 12 Resistance 14 Connection cable QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] US 8,399,115 B2

[0002]

Claims

[1] Cell monitoring system (1, 1', 1") of an electrochemical cell (2, 2', 2"), comprising a cell (2, 2', 2") designed as a wound cell (4) and at least one sensor (6), wherein the wound cell (4) is wound from two stacked electrode foils and an intermediate separator and comprises a positive terminal (2.1) and a negative terminal (2.2) at its end face, characterized by , that the at least one sensor (6) is integrated directly into the winding cell (4) or is arranged directly on the winding cell (4) and is wirelessly connectable to or coupled with an external battery management system (8). [2] Cell monitoring system (1, 1', 1") according to claim 1, characterized by , that the at least one sensor (6) is arranged in an inner cavity (4.1) of the winding cell (4). [3] Cell monitoring system (1, 1', 1") according to claim 1 or 2, characterized by, that the at least one sensor (6) is coupled to the positive terminal (2.1) and the negative terminal (2.2) for electrical supply. [4] Cell monitoring system (1, 1', 1") according to any one of the preceding claims, characterized by , that at least a pressure sensor, a temperature sensor, a level sensor, an acceleration sensor, a state of charge sensor, an electrode potential sensor and / or a battery parameter sensor is provided as a sensor (6). [5] Cell monitoring system (1, 1', 1") according to any one of the preceding claims, characterized by , that at least one resistor (12) is integrated into the winding cell (4). [6] Cell monitoring system (1, 1', 1") according to any one of the preceding claims, characterized by , that at least one communication unit (10) with an antenna (10.1) is integrated into the winding cell (4). [7] Electrochemical cell (2, 2', 2") with a cell monitoring system (1, 1', 1") according to one of the preceding claims.

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