Battery module

Abstract

To provide a battery module that can detect short-circuiting due to leak of an electrolyte solution.SOLUTION: A battery module includes a plurality of battery cells stacked in a predetermined direction, a voltage sensor that measures the voltage of each of the battery cells, and a flexible substrate disposed between the battery cells and the voltage sensor. The flexible substrate includes a plurality of wiring parts with one end side connected to electrodes of the battery cells and the other end side connected to the voltage sensor, a laminate film that insulates the wiring parts from each other by sealing the wiring parts, a fuse provided between the laminate film and the voltage sensor in each of the wiring parts, and a dummy wire branched from at least one wiring part of the wiring parts, provided in parallel to the other wiring parts, and not connected to the electrode. The fuse exists between the electrode and the place where the dummy wire is branched in the wiring part.SELECTED DRAWING: Figure 1

Description

Technical Field

[0006] , , ,

[0001] This disclosure relates to a battery module.

Background Art

[0002] Patent Document 1 discloses using a flexible printed board as a voltage detection terminal.

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the configuration disclosed in Patent Document 1, when a short circuit (such as a short circuit between flexible printed boards due to leakage of electrolyte) occurs in a circuit located closer to the battery cell side than the fuse, there is a risk that a large current cannot be suppressed by the fuse.

[0005] This disclosure has been made in view of the above, and an object thereof is to provide a battery module capable of detecting a short circuit due to leakage of electrolyte.

Means for Solving the Problems

[0006] The battery module according to this disclosure comprises a plurality of battery cells stacked in a predetermined direction, a voltage sensor for measuring the voltage of each of the plurality of battery cells, and a flexible substrate disposed between the plurality of battery cells and the voltage sensor, wherein the flexible substrate comprises a plurality of wiring sections, one end of which is connected to the electrodes of the plurality of battery cells and the other end of which is connected to the voltage sensor, a laminate film that insulates the plurality of wiring sections from each other by sealing them, fuses provided between the laminate film and the voltage sensor in each of the plurality of wiring sections, and dummy wiring that branches off from one of the plurality of wiring sections, runs parallel to the other wiring sections, and is not connected to the electrodes, wherein the fuse is provided between the point where the dummy wiring in the wiring section branches off and the electrode. [Effects of the Invention]

[0007] According to this disclosure, when electrolyte leaks, a short circuit occurs between the dummy wiring and the wiring section, causing the fuse to blow and the voltage measurement to become 0, thus enabling detection of a short circuit due to electrolyte leakage. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a perspective view showing an example of the configuration of a battery module according to an embodiment. [Figure 2] Figure 2 is a side view showing an example of the configuration of a battery module according to the embodiment. [Figure 3] Figure 3 is a schematic diagram showing the circuit structure of a battery module according to the embodiment. [Figure 4] Figure 4 is a schematic diagram showing the circuit structure of a battery module according to an embodiment, in which a short circuit occurs due to leakage of electrolyte from a battery cell. [Figure 5] Figure 5 is a schematic diagram showing the circuit structure of a modified example 1 of the battery module according to the embodiment. [Figure 6] Figure 6 is a schematic diagram showing the circuit structure of a modified example 2 of the battery module according to the embodiment. [Figure 7] Figure 7 is a side view showing an example of the configuration of a conventional battery module. [Figure 8] Figure 8 is a schematic diagram showing the circuit structure of a conventional battery module. [Modes for carrying out the invention]

[0009] A battery module according to an embodiment of this disclosure will be described with reference to the drawings. Note that the components in the following embodiments include those that are easily replaceable or substantially identical to those that are replaceable by a person skilled in the art.

[0010] The battery module according to the embodiment will be described with reference to Figures 1 to 6. The battery module according to the embodiment can be used as a battery for, for example, a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), or a battery electric vehicle (BEV).

[0011] The battery module according to this embodiment is an electrolyte battery such as a lithium-ion secondary battery. As shown in Figures 1 to 3, this battery module 1 comprises a plurality of battery cells 11, a voltage sensor 12, and a flexible printed circuit board (FPC) 13.

[0012] The battery cell 11 is, for example, a thin battery cell with a bipolar structure. These battery cells 11 are stacked in a predetermined direction. Electrodes 111 are provided on the surface of the battery cell 11. The voltage sensor 12 is for measuring the voltage of each of the multiple battery cells 11.

[0013] The flexible circuit board 13 is positioned between the multiple battery cells 11 and the voltage sensor 12. The flexible circuit board 13 also includes multiple wiring sections 131, a laminate film 132, a fuse 133, and dummy wiring 134.

[0014] One end of the wiring portion 131 is connected to the electrodes 111 of the plurality of battery cells 11, and the other end is connected to the voltage sensor 12. This wiring portion 131 is composed of, for example, a metal portion (such as a copper pattern etc.) exposed on the flexible substrate 13. Also, one end side of the wiring portion 131 functions as a voltage detection terminal of the voltage sensor 12.

[0015] Note that, as shown in FIGS. 1 and 2, the flexible substrate 13 branches (diverges) from a single substrate, and these branched portions are respectively sandwiched between the battery cells 11. Also, wiring portions 131 are respectively provided at the branched portions of this flexible substrate 13.

[0016] The laminate film 132 insulates the plurality of wiring portions 131 from each other by sealing the plurality of wiring portions 131. Also, as shown in FIG. 2, the laminate film 132 is provided at a position (a position where the branched portions approach) that is not sandwiched between the battery cells 11 at the branched portion of the flexible substrate 13.

[0017] The fuses 133 are respectively provided between the laminate film 132 and the voltage sensor 12 in the plurality of wiring portions 131. These fuses 133 blow when a short circuit occurs between the battery cells 11. Thereby, the voltage measurement value of the voltage sensor 12 becomes 0, and the short circuit is detected.

[0018] The dummy wiring 134 is for detecting the leakage of the battery cells 11. This dummy wiring 134 is composed of, for example, a metal portion (such as a copper pattern etc.) exposed on the flexible substrate 13. Note that the details of the dummy wiring 134 will be described later.

[0019] Here, FIGS. 7 and 8 show an example of the configuration of a conventional battery module and its circuit structure. In this battery module 101 as well, fuses 133 are mounted on the flexible substrate 13. However, if a short circuit occurs between the battery cells 11 on the side closer to the battery cells 11 than these fuses 133, the fuses 133 do not blow. Also, in the battery module 101, when the resistance value of the short circuit location is high, the short circuit current is small, so heat is generated gradually. Therefore, in the conventional battery module 101, a short circuit between the battery cells 11 could not be detected.

[0020] Therefore, in the battery module 1 according to the embodiment, as shown in FIG. 3, the above problem is solved by providing a dummy wiring 134 on the flexible substrate 13. This dummy wiring 134 is provided so as to branch from one of the plurality of wiring portions 131. More specifically, the dummy wiring 134 branches from a wiring portion 131 connected to a battery cell 11 having a lower potential than the location where leakage is to be detected (hereinafter referred to as the "leakage detection location").

[0021] Also, the dummy wiring 134 is provided so as to run parallel to other wiring portions 131. "Other wiring portions 131" refers to the wiring portions 131 other than the wiring portion 131 that is the branch source of the dummy wiring 134 among the plurality of wiring portions 131. Also, the dummy wiring 134 is separated from the other parallel-running wiring portions 131 by a predetermined distance and is not connected to the other wiring portions 131. That is, the dummy wiring 134 is not connected to the electrode 111 of the battery cell 11 and is provided so as to run parallel to the wiring portion 131 connected to the electrode 111.

[0022] For example, in the example of FIG. 3, the dummy wiring 134 branches from a wiring portion 131 connected to the electrode 111 of the battery cell 11 having the lowest potential among the plurality of wiring portions 131. "The battery cell 11 having the lowest potential" refers to, for example, the battery cell 11 arranged at the lowermost side in the same figure (see part A).

[0023] Furthermore, the dummy wiring 134 is provided to run parallel to the wiring section 131 connected to the electrode 111 of the battery cell 11 with the highest potential among the multiple wiring sections 131. The "battery cell 11 with the highest potential" refers, for example, to the battery cell 11 located at the top in the figure (see section B). By providing the dummy wiring 134 in this way, it is possible to detect liquid leakage at the "liquid leakage detection location X" shown in Figure 3.

[0024] Furthermore, the dummy wiring 134 is provided to run parallel to the wiring section 131 connected to the electrodes 111 of the battery cell 11 between the battery cell 11 with the lowest potential and the battery cell 11 with the highest potential among the multiple wiring sections 131. Specifically, this wiring section 131 is the fourth wiring section 131 from the top in Figure 3. By providing the dummy wiring 134 in this way, it is possible to detect liquid leakage at the "liquid leakage detection location Y" shown in the figure.

[0025] Furthermore, in Figure 3, a fuse 133 is provided between the branching point of the dummy wiring 134 in the wiring section 131 and the battery cell 11 (electrode 111). Note that the dummy wiring 134 can be freely wired according to the location where leakage detection is to be performed, and is not limited to what is shown in Figure 3.

[0026] In the battery module according to the embodiment described above, the dummy wiring 134 is provided so as to be spaced a predetermined distance apart from and running parallel to the other wiring sections 131. Furthermore, the short circuit formed by this dummy wiring 134 is connected to the wiring section 131 on the voltage sensor 12 side of each fuse 133.

[0027] As a result, in the battery module according to this embodiment, for example as shown in Figure 4, when the electrolyte of the battery cell 11 leaks, the dummy wiring 134 and the wiring section 131 (the wiring section 131 running parallel to the dummy wiring 134) short-circuit. Then, a short-circuit current flows through the dummy wiring 134 to the wiring section 131 at the branching point of the dummy wiring 134, causing the fuse 133 to blow. As a result, the voltage measurement value by the voltage sensor 12 becomes 0, making it possible to detect a short circuit (abnormality) due to electrolyte leakage.

[0028] Furthermore, in the battery module according to this embodiment, as described above, the dummy wiring 134 is branched from the wiring section 131 connected to the battery cell 11 with the lowest potential, and is provided to run parallel to the wiring section 131 connected to the battery cell 11 with the highest potential. This maximizes the voltage difference, resulting in the maximum short-circuit current when the electrolyte of the battery cell 11 leaks, thus ensuring that the fuse 133 blows more reliably.

[0029] Furthermore, in the battery module according to this embodiment, the position of the fuse 133 can be freely set, thus improving the design flexibility of the circuit. In addition, in the battery module according to this embodiment, there is no need to prepare a separate sensor for detecting liquid leakage, so it is possible to achieve liquid leakage detection in a small size and space-saving manner.

[0030] (Variation 1) A modified example 1 of the battery module according to the embodiment will be described with reference to Figure 5. The battery module 1A according to Modified Example 1 comprises a plurality of battery cells 11, a voltage sensor 12, and a flexible substrate 13. The flexible substrate 13 also has four dummy wires 134A instead of the dummy wire 134 in Figure 3. These dummy wires 134A are provided so as to run parallel to the four wiring sections 131. As a result, the battery module 1A has four leak detection points.

[0031] As shown in Figure 5, the leak detection points of the dummy wiring 134A can be set arbitrarily. For example, they can be set precisely at locations where leaks are likely to occur, or if the locations where leaks are likely to occur are unknown, they can be set for all cells. Also, similar to the battery module 1 described above, in order to reliably blow the fuse 133, it is preferable to set the branching point of the dummy wiring 134A to the lowest potential wiring section 131, and to run the dummy wiring 134A, which will be the leak detection point, parallel to the highest potential wiring section 131.

[0032] (Modification 2) A modified example 2 of the battery module according to the embodiment will be described with reference to Figure 6. The battery module 1B according to modified example 2 comprises a plurality of battery cells 11, a voltage sensor 12, and a flexible substrate 13. The flexible substrate 13 also has two independent dummy wires 134B instead of the dummy wire 134 in Figure 3. These dummy wires 134B each branch off from different wiring sections 131 (see "branching points"). Furthermore, these dummy wires 134B are provided to run parallel to the two wiring sections 131. As a result, the battery module 1B has two leak detection points.

[0033] As shown in Figure 6, the leakage detection point of the dummy wiring 134B can be set arbitrarily. For example, as shown in the figure, it may be branched from a point where several cells are short-circuited so that the short-circuit current does not become too large during a short circuit. Also, similar to the battery module 1 described above, in order to reliably blow the fuse 133, it is preferable to set the branching point of the dummy wiring 134B to the lowest potential wiring section 131 and run the dummy wiring 134B, which is the leakage detection point, parallel to the highest potential wiring section 131.

[0034] Further effects and modifications can be readily derived by those skilled in the art. Therefore, broader aspects of the present invention are not limited to the specific details and representative embodiments expressed and described above. Accordingly, various modifications are possible without departing from the spirit or scope of the overall concept of the invention as defined by the appended claims and their equivalents. [Explanation of Symbols]

[0035] 1, 1A, 1B, 101 Battery Module 11 battery cells 111 Electrode 12 Voltage Sensor 13 Flexible printed circuit boards (FPCs) 131 Wiring section 132 Laminating Film 133 fuses 134, 134A, 134B Dummy Wiring

Claims

1. Multiple battery cells stacked in a predetermined direction, A voltage sensor for measuring the voltage of each of the aforementioned multiple battery cells, A flexible substrate is disposed between the plurality of battery cells and the voltage sensor, Equipped with, The aforementioned flexible substrate is Multiple wiring sections, one end of which is connected to the electrodes of the multiple battery cells and the other end of which is connected to the voltage sensor, A laminate film that seals the plurality of wiring sections to insulate the plurality of wiring sections from each other, In the aforementioned plurality of wiring sections, a fuse is provided between the laminate film and the voltage sensor, A dummy wire is provided that branches off from one of the aforementioned multiple wiring sections, runs parallel to the other wiring sections, and is not connected to the electrodes. Equipped with, The fuse is provided between the point where the dummy wiring in the wiring section branches and the electrode. Battery module.

2. The aforementioned dummy wiring is, Of the aforementioned wiring sections, branch off from the wiring section connected to the electrode of the battery cell with the lowest potential, Among the aforementioned wiring sections, the wiring section connected to the electrode of the battery cell with the highest potential is provided to run parallel to it. The battery module according to claim 1.

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