Patent Application
20240194954
This application claims priority to Japanese Patent Application No. 2022-195952 filed on Dec. 7, 2022, incorporated herein by reference in its entirety.
The present disclosure relates to a liquid leakage detection system and a stacked cell module.
WO2019/102986 discloses a technology in which a liquid leakage sensor is disposed in a leaked liquid retention region (portion where an electrolytic solution is likely to stay when the electrolytic solution leaks from a battery cell).
In a case where each cell includes a voltage detection terminal for detecting a voltage in each cell, liquid junction may occur between the voltage detection terminals of the cells before liquid leakage is detected by the liquid leakage sensor in the configuration of WO2019/102986.
The present disclosure has been made in view of the above, and an object thereof is to provide a liquid leakage detection system and a stacked cell module in which the occurrence of liquid junction can be reduced between voltage detection terminals of cells.
A liquid leakage detection system according to the present disclosure includes:a stacked cell module including a plurality of cells stacked along a gravitational direction; a connector electrically connected to the cells; and a processor configured to determine whether liquid leakage occurs in the stacked cell module based on an electrical signal input from the connector. Each of the cells includes: a plate-shaped secondary battery; a sealing portion that contains the cell and seals an outer periphery of the cell; a voltage detection terminal including one end electrically connected to a cathode or an anode of the secondary battery and the other end exposed to an outside of the sealing portion; and a liquid leakage detection terminal electrically insulated from the secondary battery and the voltage detection terminal, positioned immediately below the voltage detection terminal, and fixed to the sealing portion. The connector includes liquid leakage detection terminal connection portions to which the liquid leakage detection terminals are electrically connected. The processor is configured to determine whether liquid junction occurs between the voltage detection terminal and the liquid leakage detection terminal based on an electrical signal input from the liquid leakage detection terminal connection portion.
A stacked cell module according to the present disclosure includes a plurality of cells stacked along a gravitational direction. Each of the cells includes: a plate- shaped secondary battery; a sealing portion that contains the cell and seals an outer periphery of the cell; a voltage detection terminal including one end electrically connected to a cathode or an anode of the secondary battery and the other end exposed to an outside of the sealing portion; and a liquid leakage detection terminal electrically insulated from the secondary battery and the voltage detection terminal, positioned immediately below the voltage detection terminal, and fixed to the sealing portion.
According to the present disclosure, it is possible to realize the liquid leakage detection system and the stacked cell module in which the occurrence of liquid junction can be reduced between the voltage detection terminals of the cells.
Features, advantages, and technical and industrial significance of exemplary embodiments of the disclosure will be described below with reference to the accompanying drawings, in which like signs denote like elements, and wherein:
A liquid leakage detection system and a stacked cell module according to an embodiment of the present disclosure will be described with reference to the drawings. Incidentally, the constituent elements in the following embodiments include those that can be easily replaced by a person skilled in the art or those that are substantially the same.
The liquid leakage detection system includes the stacked cell module 1 illustrated in
The secondary battery 11 has, for example, a plate shape and is stacked in a bipolar structure along the gravitational direction. The secondary battery 11 includes a cathode and an anode, a resin frame, an electrolyte, and a separator. The cathode and the anode are coated on a copper foil or an aluminum foil forming the output surface 13 and are arranged so as to face each other. The resin frame forms the sealing portion 12. The electrolyte is filled inside the resin frame. The separator is disposed inside the resin frame and electrically insulates the cathode and the anode from each other.
The sealing portion 12 stores the cells and seals the outer periphery of the cells. The sealing portion 12 has an insulating property and is made of, for example, resin.
The output surface 13 outputs electric power of the secondary battery 11.
The plurality of cells 10 is stacked so that the output surface 13 of each cell 10 is in contact with each other. With this configuration, a plurality of cells 10 is connected in series. As described above, the stacked cell module 1 having a bipolar structure is formed. Since the stacked cell module 1 has a bipolar structure, a high-voltage battery cell can be formed.
One end of the voltage detection terminal 14 is electrically connected to a cathode or an anode of the secondary battery 11. The other end of the voltage detection terminal 14 is exposed to the outside of the sealing portion 12. The voltage detection terminals 14 of the cells 10 are arranged at different positions in the horizontal direction.
The liquid leakage detection terminal 15 is electrically insulated from the secondary battery 11 and the voltage detection terminal 14. The liquid leakage detection terminal 15 is located directly below the voltage detection terminal 14 and is fixed to the sealing portion 12. The liquid leakage detection terminal 15 may be embedded in the sealing portion 12. However, the liquid leakage detection terminal 15 may be adhered to the surface of the sealing portion 12.
The voltage detection terminal 14 is electrically connected to the voltage detection terminal connection portion 21.
A liquid leakage detection terminal 15 is electrically connected to the liquid leakage detection terminal connection portion 22.
The liquid leakage determination unit 3 is, for example, a personal computer. The liquid leakage determination unit 3 includes a processor including, for example, Central Processing Unit (CPU), Digital Signal Processor (DSP), Field-Programmable Gate Array (FPGA), and the like, and a memory (main storage unit) including, Random Access Memory (RAM), Read Only Memory (ROM), and the like.
The liquid leakage determination unit 3 determines whether or not the voltage detection terminal 14 and the liquid leakage detection terminal 15 are in liquid junction based on the electrical signals input from the voltage detection terminal connection portion 21 and the liquid leakage detection terminal connection portion 22.
An electrical signal from the voltage detection terminal connection portion 21 is input to the voltage detection unit 31.
An electrical signal from the liquid leakage detection terminal connection portion 22 is input to the liquid leakage detection unit 32.
The voltage calculation unit 33 calculates the voltage at the voltage detection terminal 14 based on the electrical signal from the voltage detection terminal connection portion 21 input via the voltage detection unit 31. Further, the voltage calculation unit 33 calculates the voltage at the liquid leakage detection terminal 15 based on the electrical signal from the liquid leakage detection terminal connection portion 22 input via the liquid leakage detection unit 32.
The liquid leakage determination unit 34 determines whether or not each cell 10 is leaking by using the voltage of the liquid leakage detection terminal 15. When the liquid does not leak from the interface between the sealing portion 12 and the voltage detection terminal 14, no voltage is applied to the liquid leakage detection terminal 15 from the outside. Therefore, the liquid leakage determination unit 34 determines that the liquid is not leaking if the voltage of the liquid leakage detection terminal 15 calculated by the voltage calculation unit 33 is the discharge pressure. On the other hand, when the electrolyte of the secondary battery 11 leaks from the interface between the sealing portion 12 and the voltage detection terminal 14, the leaked electrolyte drips downward due to gravity and may reach the liquid leakage detection terminal 15 located immediately below. When the leaked electrolyte reaches the liquid leakage detection terminal 15, a voltage from the secondary battery 11 is applied to the liquid leakage detection terminal 15. Therefore, the liquid leakage determination unit 34 determines that the liquid leakage has occurred if the voltage of the liquid leakage detection terminal 15 calculated by the voltage calculation unit 33 is not the solution discharge pressure but the actual voltage.
According to the first embodiment described above, each cell 10 of the stacked cell module 1 includes the liquid leakage detection terminal 15 located directly below the voltage detection terminal 14. Therefore, when the liquid leaks from the interface between the sealing portion 12 and the voltage detection terminal 14, the leaked electrolyte immediately reaches the liquid leakage detection terminal 15 located immediately below. As a result, the liquid leakage of each cell 10 can be detected before the liquid junction occurs between the voltage detection terminals 14 of each cell 10. In addition, it is possible to reduce a liquid junction from occurring between the voltage detection terminals 14 of the cells 10.
In each cell 10 of the stacked cell module 1, the voltage detection terminals 14 are arranged at different positions in the horizontal direction. Therefore, in the stacked cell module 1, it is difficult for a liquid junction to occur between the voltage detection terminals 14 of the cells 10.
In the case where the liquid leakage determination unit 3 does not use the high voltage of the stacked cell module 1 as a driving power source and an external low voltage source is used as a power source, the liquid leakage determination unit 3 may determine the liquid leakage by detecting that the high voltage and the low voltage are short-circuited or resistance-short-circuited.
The liquid leakage detection unit 35B detects whether or not an electric leakage has occurred in the stacked cell module 1 based on an electrical signal from the liquid leakage detection terminal connection portion 22 inputted via the liquid leakage detection unit 32.
When the liquid leakage detection unit 35B detects that an electric leakage has occurred in the stacked cell module 1, the liquid leakage determination unit 34B determines that a liquid leakage has occurred in the stacked cell module 1.
According to the liquid leakage determination unit 3B, the voltage calculation unit 33 may not calculate the voltage at the liquid leakage detection terminal 15. Therefore, it is possible to easily determine whether or not the stacked cell module 1 is leaking, while reducing the workload of the liquid leakage determination unit 3B.
Additional benefits and variations can be readily derived by one of ordinary skill in the art. Thus, the broader aspects of the disclosure are not limited to the specific details and representative embodiments presented and described above. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2022-195952 | Dec 2022 | JP | national |
