Voltage detection device, battery module, and electronic device

Abstract

A voltage detection device (20) for detecting the voltage of a battery cell (10) comprises: a flexible substrate (22); and a first temperature detection element (251) electrically connected to the flexible substrate (22). In the flexible substrate (22), a first branch extending region (225), in which the first temperature detection element (251) is located, is bent with respect to a second main extending region (222) of the battery cell (10) such that the first temperature detection element (251) is in contact with or in proximity to the battery cell (10).

Description

Voltage detection device, battery module and electronic device

[0001] The present invention relates to a voltage detection device, a battery module and an electronic device.

[0002] In recent years, various battery modules have been developed. A battery module may include a battery cell and a voltage detection device for detecting the voltage of the battery cell. The voltage detection device may have a flexible substrate such as Flexible Printed Circuits (FPC). FPC can be bent into various shapes. For example, as described in Patent Document 1, an FPC may be bent from a U-shape to an L-shape. As described in Patent Document 2, an FPC may be wound around a hinge shaft.

[0003] International Publication No. 2010 / 073436, Japanese Unexamined Patent Publication No. 2007-208146

[0004] An electronic device such as a voltage detection device for detecting the voltage of a battery cell may include a flexible substrate such as an FPC, and a temperature detection element such as a thermistor electrically connected to the flexible substrate. It may be necessary to accurately detect the temperature of a measurement object such as a battery cell by such a temperature detection element.

[0005] An object of the present invention is to accurately detect the temperature of a measurement object such as a battery cell by a temperature detection element electrically connected to a flexible substrate. Other objects of the present invention will become apparent from the description of the present specification.

[0006] One aspect of the present invention is as follows: 1. A voltage detection device for detecting the voltage of a battery cell, comprising: a flexible substrate; and a temperature detection element electrically connected to the flexible substrate, wherein the portion of the flexible substrate on which the temperature detection element is located is bent relative to the other portion of the flexible substrate so that the temperature detection element contacts or is in close proximity to the battery cell. 2. The voltage detection device according to 1, further comprising an electrical component located on the other portion of the flexible substrate, wherein the temperature detection element and the electrical component are located on the same side of the flexible substrate when the flexible substrate is unfolded. 3. The voltage detection device according to 2, wherein the electrical component has at least one of a voltage detection terminal electrically connected to the battery cell and a connector electrically connected to the voltage detection terminal. 4. The voltage detection device according to 2 or 3, wherein the portion and the other portion of the flexible substrate extend at least partially in substantially the same direction. 5. A battery module comprising: a battery cell; and the voltage detection device according to any one of 1 to 4. 6. An electronic device comprising a flexible substrate and a temperature sensing element electrically connected to the flexible substrate, wherein the portion of the flexible substrate on which the temperature sensing element is located is bent relative to the other portion of the flexible substrate so that the temperature sensing element contacts or is in close proximity to the object to be measured by the temperature sensing element.

[0007] According to the above embodiment of the present invention, the temperature of a target to be measured, such as a battery cell, can be accurately detected by a temperature detection element electrically connected to a flexible substrate.

[0008] This is an exploded perspective view of a part of a battery module according to an embodiment. This is a developed view of a flexible substrate according to an embodiment. This is a diagram illustrating the bending of a flexible substrate according to an embodiment. This is a plan view of a film from which a plurality of flexible substrates according to an embodiment are cut. This is a developed view of a flexible substrate according to a modified example 1. This is a diagram illustrating the bending of a flexible substrate according to a modified example 1. This is a developed view of a flexible substrate according to a modified example 2.

[0009] Embodiments and modified examples of the present invention will be described below with reference to the drawings. In all drawings, similar components are denoted by the same reference numerals, and their descriptions are omitted where appropriate.

[0010] Figure 1 is an exploded perspective view of a part of the battery module 1 according to the embodiment. Figure 2 is an unfolded view of the flexible substrate 22 according to the embodiment.

[0011] Figures 1 and 2 show the X-axis, Y-axis, and Z-axis, respectively, for illustrative purposes. In Figure 2, the white circle with an X indicating the X-axis indicates that the X-axis arrow is pointing towards the back of the page. The X-axis indicates the front-to-back direction of the battery module 1. The Y-axis is one of the directions perpendicular to the X-axis and indicates the left-to-right direction of the battery module 1. The Z-axis is a direction perpendicular to both the X-axis and Y-axis and indicates the up-to-down direction of the battery module 1. Hereafter, unless otherwise specified, the directions indicated by the X-axis arrow, the Y-axis arrow, and the Z-axis arrow will be described as the rear, right, and up directions of the battery module 1, respectively. The front-to-back, left-to-right, and up-to-down directions of the battery module 1 are not limited to the examples described above.

[0012] Unless otherwise specified, the +X side or +X refers to the side indicated by the arrow on the X axis, and the -X side or -X refers to the opposite side of the side indicated by the arrow on the X axis. Unless otherwise specified, the +Y side or +Y refers to the side indicated by the arrow on the Y axis, and the -Y side or -Y refers to the opposite side of the side indicated by the arrow on the Y axis. Unless otherwise specified, the +Z side or +Z refers to the side indicated by the arrow on the Z axis, and the -Z side or -Z refers to the opposite side of the side indicated by the arrow on the Z axis.

[0013] Referring to Figure 1, the battery module 1 according to the embodiment will be described. The battery module 1 according to the embodiment includes a plurality of battery cells 10, a voltage detection device 20, and a busbar 30.

[0014] Multiple battery cells 10 are stacked in the Y direction. Each battery cell 10 has an outer casing 11, a positive terminal 12, and a negative terminal 13.

[0015] The outer casing 11 seals a battery element (not shown) and an electrolyte. In one example, the battery element includes a plurality of positive electrodes and a plurality of negative electrodes stacked alternately in the Y direction, and a separator located between adjacent positive and negative electrodes in the Y direction. The positive and negative electrodes may be wound around a winding shaft extending in a predetermined direction. Each battery cell 10 may be an all-solid-state battery that does not use an electrolyte. The portion of the outer casing 11 that seals the battery element has a substantially rectangular parallelepiped shape with a pair of faces substantially perpendicular to the X direction, a pair of faces substantially parallel to the Y direction, and a pair of faces substantially parallel to the Z direction. The dimensions of each side of this portion of the outer casing 11 are in the order of the sides substantially parallel to the Y direction, the sides substantially parallel to the Z direction, and the sides substantially parallel to the X direction being the longest. The shape of each battery cell 10 is not limited to the example shown in Figure 1.

[0016] The positive terminal 12 is electrically connected to the positive electrode of the battery element, and the negative terminal 13 is electrically connected to the negative electrode of the battery element. In some embodiments, the positive terminal 12 is formed of at least one of aluminum and an aluminum alloy. In some embodiments, the negative terminal 13 is formed of at least one of copper and a copper alloy. The materials used to form the positive terminal 12 and the negative terminal 13 are not limited to those described above. The positive terminal 12 is drawn out from one of the +X side and -X side of the housing material 11, and the negative terminal 13 is drawn out from the other of the +X side and -X side of the housing material 11.

[0017] In the battery module 1, multiple battery cells 10 connected in parallel are connected in series. Hereafter, unless otherwise specified, "parallel battery cell 10" refers to battery cells 10 connected in parallel. In the example shown in Figure 1, the parallel battery cell 10 includes two battery cells 10 adjacent to each other in the Y direction. The two battery cells 10 included in the parallel battery cell 10 are connected in parallel by the positive terminals 12 located on one of the +X and -X sides of the two battery cells 10 being electrically connected to each other, and the negative terminals 13 located on the other of the +X and -X sides of the two battery cells 10 being electrically connected to each other. Two parallel battery cells 10 adjacent to each other in the Y direction are connected in series by the positive terminal 12 located on one of the +X and -X sides of one of the parallel battery cells 10 and the negative terminal 13 located on one of the +X and -X sides of the other parallel battery cell 10 being electrically connected to each other. Unless otherwise specified, the terminal group 14 refers to the positive terminal 12 located on one of the +X and -X sides of one of two parallel battery cells 10 adjacent in the Y direction, and the negative terminal 13 located on one of the +X and -X sides of the other parallel battery cell 10 adjacent in the Y direction. The positive terminal 12 and negative terminal 13 included in the terminal group 14 are electrically connected to each other. Multiple parallel battery cells 10 are connected in series via multiple terminal groups 14 that are alternately located in the X direction, from the parallel battery cell 10 located at one end of the multiple battery cells 10 in the Y direction to the parallel battery cell 10 located at the other end of the multiple battery cells 10 in the Y direction.

[0018] The electrical connections of the multiple battery cells 10 are not limited to the examples of the embodiment. For example, the parallel battery cells 10 may include three or more battery cells 10 connected in parallel. Alternatively, instead of multiple parallel battery cells 10, multiple single battery cells 10 may be connected in series.

[0019] The voltage detection device 20 will be described with reference to Figures 1 and 2. The voltage detection device 20 is configured to detect the voltage of multiple terminal groups 14 on the -X side of multiple battery cells 10. As shown in Figures 1 and 2, the voltage detection device 20 includes a protector 21, a flexible substrate 22, multiple voltage detection terminals 23, a connector 24, a first temperature detection element 251, a second temperature detection element 252, a third temperature detection element 253, a fourth temperature detection element 254, a first support plate 261, a second support plate 262, a third support plate 263, and a fourth support plate 264.

[0020] In Figure 2, the flexible substrate 22 is unfolded in the same plane perpendicular to the X direction. Hereinafter, the first surface 22a of the flexible substrate 22 refers to the surface located on the -X side of the flexible substrate 22 when the flexible substrate 22 is unfolded as shown in Figure 2, and the second surface 22b of the flexible substrate 22 refers to the surface located on the +X side of the flexible substrate 22 when the flexible substrate 22 is unfolded as shown in Figure 2. In Figure 2, the protector 21, the first support plate 261, the second support plate 262, the third support plate 263, and the fourth support plate 264 are omitted.

[0021] As shown in Figure 1, the protector 21 is positioned on the -X side portion of the plurality of battery cells 10. The protector 21 has electrical insulating properties and is made of a resin such as PBT (polybutylene terephthalate). The protector 21 defines a plurality of openings 211 that expose a plurality of +X side terminal groups 14. The protector 21 covers substantially the entire +X side portion of the plurality of battery cells 10, except for the portion that overlaps with the plurality of openings 211 of the plurality of battery cells 10 in the X direction.

[0022] The flexible substrate 22 is, for example, a flexible printed circuit board (FPC). The flexible substrate 22 may be a single-sided FPC or a double-sided FPC.

[0023] As shown in Figure 2, the flexible substrate 22 includes a first main extension region 221, a second main extension region 222, a third main extension region 223, a fourth main extension region 224, a first branch extension region 225, a second branch extension region 226, a third branch extension region 227, and a fourth branch extension region 228.

[0024] As shown in Figure 2, when the flexible substrate 22 is unfolded, the first main extension region 221 extends in the Y direction between the +Y side end and the -Y side end of the -Z side end of the flexible substrate 22. The second main extension region 222 extends from approximately the center of the first main extension region 221 in the Y direction toward the +Z side. The third main extension region 223 extends from the +Z side end of the second main extension region 222 toward the +Y side. The fourth main extension region 224 extends from the -Y side end of the first main extension region 221 toward the +Z side. As shown in Figure 1, when the flexible substrate 22 is assembled to the voltage detection device 20, the first main extension region 221, the second main extension region 222, the third main extension region 223, and the fourth main extension region 224 are located on the -X side of the protector 21 around the multiple openings 211.

[0025] As shown in Figure 1, the protector 21 has a plurality of bosses 212 on its -X side. The plurality of bosses 212 penetrate the first main extension region 221, the second main extension region 222, the third main extension region 223, and the fourth main extension region 224. The protector 21 and the flexible substrate 22 are fixed to each other by heat crimping the -X side tips of the plurality of bosses 212 while they are penetrating the first main extension region 221, the second main extension region 222, the third main extension region 223, and the fourth main extension region 224. Heat crimping the -X side tips of the bosses 212 prevents the flexible substrate 22 from detaching from the protector 21. Because the protector 21 and the flexible substrate 22 are fixed to each other, the flexible substrate 22 is supported by the protector 21. The method for fixing the protector 21 and the flexible substrate 22 is not limited to the method described above.

[0026] As shown in Figure 2, when the flexible substrate 22 is unfolded, the first branch extension region 225 branches off from the +Z side end of the -Y side of the second main extension region 222 and extends toward the -Y side. The second branch extension region 226 includes the first diagonal extension region 226p and the first transverse extension region 226q. The first diagonal extension region 226p branches off from the +Z side end of the +Y side of the fourth main extension region 224 and extends diagonally toward the -Z side with respect to the +Y direction. The first transverse extension region 226q extends toward the +Y side from the +Y side end of the first diagonal extension region 226p. The third branch extension region 227 branches off from approximately the center of the -Z side in the Y direction of the first main extension region 221 and extends toward the -Y side. The fourth branch extension region 228 branches off from the -Y side end of the -Z side of the first main extension region 221 and extends to the +Y side. As shown in Figure 1, when the flexible substrate 22 is assembled to the voltage detection device 20, the first branch extension region 225, the second branch extension region 226, the third branch extension region 227, and the fourth branch extension region 228 are drawn out from the protector 21 to the +X side.

[0027] Each voltage detection terminal 23 has a substantially plate shape that is substantially perpendicular to the X direction. Viewed from the -X side, each voltage detection terminal 23 has a substantially rectangular shape with a pair of short sides substantially parallel to the Y direction and a pair of long sides substantially parallel to the Z direction. The shape of each voltage detection terminal 23 is not limited to the example shown in Figure 1. As shown in Figures 1 and 2, the -Z side end of each voltage detection terminal 23 is located on the -X side with respect to the first main extension region 221. Each voltage detection terminal 23 and the first main extension region 221 are electrically connected to each other by conductivity such as soldering. The -X faces of each terminal group 14 on the -X side and the +X faces of each voltage detection terminal 23 are joined to each other, for example by laser welding. Therefore, each terminal group 14 and each voltage detection terminal 23 on the -X side are electrically connected to each other.

[0028] As shown in Figures 1 and 2, the connector 24 is located on the -X side relative to the +Y side end of the third main extension region 223. The connector 24 and the third main extension region 223 are electrically connected to each other by conductivity such as soldering.

[0029] The first temperature detection element 251, the second temperature detection element 252, the third temperature detection element 253, and the fourth temperature detection element 254 are, for example, thermistors. As shown in Figure 2, when the flexible substrate 22 is unfolded, the first temperature detection element 251, the second temperature detection element 252, the third temperature detection element 253, and the fourth temperature detection element 254 are located on the -X side with respect to the -Y side tip of the first branch extension region 225, the +Y side tip of the second branch extension region 226, the -Y side tip of the third branch extension region 227, and the +Y side tip of the fourth branch extension region 228, respectively. The first temperature detection element 251, the second temperature detection element 252, the third temperature detection element 253, and the fourth temperature detection element 254 are electrically connected to the first branch extension region 225, the second branch extension region 226, the third branch extension region 227, and the fourth branch extension region 228, respectively, by conductivity such as soldering. The first temperature detection element 251, the second temperature detection element 252, the third temperature detection element 253, and the fourth temperature detection element 254 may also be electrically connected to the connector 24 via the flexible substrate 22.

[0030] As shown in Figure 1, the first support plate 261 protrudes from approximately the center in the Y direction of the +Z side end of the protector 21 toward the +X side. The second support plate 262 protrudes from the -Y side end of the +Z side end of the protector 21 toward the +X side. The third support plate 263 protrudes from approximately the center in the Y direction of the -Z side end of the protector 21 toward the +X side. The fourth support plate 264 protrudes from the -Y side end of the -Z side end of the protector 21 toward the +X side. In the example shown in Figure 1, the first support plate 261, the second support plate 262, the third support plate 263, and the fourth support plate 264 support the first branch extension region 225, the second branch extension region 226, the third branch extension region 227, and the fourth branch extension region 228, respectively. As shown in Figure 1, when the first branch extension region 225 is supported by the first support plate 261, the +X-side tip of the first branch extension region 225 is located on the -Z side relative to the first support plate 261. When the second branch extension region 226 is supported by the second support plate 262, the +X-side tip of the second branch extension region 226 is located on the -Z side relative to the second support plate 262. When the third branch extension region 227 is supported by the third support plate 263, the +X-side tip of the third branch extension region 227 is located on the +Z side relative to the third support plate 263. When the fourth branch extension region 228 is supported by the fourth support plate 264, the +X-side tip of the fourth branch extension region 228 is located on the +Z side relative to the fourth support plate 264.

[0031] As shown in Figure 1, the busbar 30 is provided at the -Y end of the protector 21. The busbar 30 is electrically connected to the positive terminal 12 that is drawn out to the -X side from the parallel battery cell 10 located at the -Y end.

[0032] In the example shown in Figure 1, a voltage detection device 20 located on the -X side relative to a plurality of battery cells 10 is illustrated. In this embodiment, a voltage detection device, not shown in Figure 1, is also located on the +X side relative to the plurality of battery cells 10. In one example, the voltage detection device located on the +X side relative to the plurality of battery cells 10 can be substantially the same as the voltage detection device 20 shown in Figure 1.

[0033] Figure 3 is a diagram illustrating the bending of the flexible substrate 22 according to the embodiment.

[0034] Referring to Figures 2 and 3, the assembly of the flexible substrate 22 to the voltage detection device 20 in the embodiment will be described. In the assembly of the flexible substrate 22 to the voltage detection device 20, the first branch extension region 225, the second branch extension region 226, the third branch extension region 227, and the fourth branch extension region 228 are bent as follows.

[0035] The folding of the first branch extension region 225 will now be explained. First, as shown in Figure 3, the first branch extension region 225 is folded to the +Z side so that a valley fold is formed along the first virtual line 225a shown in Figure 2 on the first surface 22a side. In Figure 3, the first temperature detection element 251 is oriented to the +X side. Next, the first branch extension region 225 is folded to the +X side so that a mountain fold is formed along the second virtual line 225b shown in Figure 3 on the second surface 22b side. By folding the first branch extension region 225 to the +X side using the first virtual line 225a and the second virtual line 225b as creases, the first temperature detection element 251 is oriented to the -Z side.

[0036] In this embodiment, the first branch extension region 225 is bent relative to the second main extension region 222 such that the first temperature detection element 251 contacts or is close to the +Z side portion of the battery cell 10. Contact between the first temperature detection element 251 and the battery cell 10 means that the first temperature detection element 251 and the battery cell 10 are in contact without any members such as the first branch extension region 225 or the first support plate 261 between them. Close proximity between the first temperature detection element 251 and the battery cell 10 means that the first temperature detection element 251 and the battery cell 10 are at a distance from each other and facing each other without any members such as the first branch extension region 225 or the first support plate 261 between them. If a member such as the first support extension region 225 or the first support plate 261 is present between the +Z side portion of the battery cell 10 and the first temperature detection element 251, this member may hinder the accurate detection of the temperature of the battery cell 10 by the first temperature detection element 251. In this embodiment, the temperature of the battery cell 10 can be accurately detected by the first temperature detection element 251 compared to the case where a member such as the first support extension region 225 or the first support plate 261 is present between the +Z side portion of the battery cell 10 and the first temperature detection element 251.

[0037] The bending of the first branch extension region 225 is not limited to the above example, as long as the first branch extension region 225 is bent towards the +X side so that the first temperature detection element 251 is oriented towards the -Z side.

[0038] The folding of the second branch extension region 226 will now be explained. First, as shown in Figure 3, the second branch extension region 226 is folded to the +Z side so that a valley fold is formed along the third virtual line 226a shown in Figure 2 on the first surface 22a side. In Figure 3, the second temperature detection element 252 is oriented to the +X side. Next, the first transverse extension region 226q is folded to the +X side so that a mountain fold is formed along the fourth virtual line 226b shown in Figure 3 on the second surface 22b side. By folding the second branch extension region 226 to the +X side using the third virtual line 226a and the fourth virtual line 226b as creases, the second temperature detection element 252 is oriented to the -Z side.

[0039] In this embodiment, the second support extension region 226 is bent relative to the fourth main extension region 224 so that the second temperature detection element 252 contacts or is close to the +Z side portion of the battery cell 10. Therefore, the temperature of the battery cell 10 can be accurately detected by the second temperature detection element 252, compared to the case where a member such as the second support extension region 226 or the second support plate 262 is present between the +Z side portion of the battery cell 10 and the second temperature detection element 252.

[0040] The bending of the second branch extension region 226 is not limited to the above example, as long as the second branch extension region 226 is bent towards the +X side so that the second temperature detection element 252 is oriented towards the -Z side.

[0041] The folding of the third branch extension region 227 will now be explained. First, as shown in Figure 3, the third branch extension region 227 is folded to the -Z side so that a valley fold is formed along the fifth imaginary line 227a shown in Figure 2 on the first surface 22a side. In Figure 3, the third temperature detection element 253 is oriented to the +X side. Next, the third branch extension region 227 is folded to the +X side so that a mountain fold is formed along the sixth imaginary line 227b shown in Figure 3 on the first surface 22a side. By folding the third branch extension region 227 to the +X side using the fifth imaginary line 227a and the sixth imaginary line 227b as creases, the third temperature detection element 253 is oriented to the +Z side.

[0042] In this embodiment, the third support extension region 227 is bent relative to the first main extension region 221 such that the third temperature detection element 253 contacts or is close to the -Z side portion of the battery cell 10. Therefore, the temperature of the battery cell 10 can be accurately detected by the third temperature detection element 253 compared to when there are members such as the third support extension region 227 or the third support plate 263 between the -Z side portion of the battery cell 10 and the third temperature detection element 253.

[0043] The bending of the third branch extension region 227 is not limited to the above example, as long as the third branch extension region 227 is bent towards the +X side so that the third temperature detection element 253 is oriented towards the +Z side.

[0044] The folding of the fourth branch extension region 228 will be described. First, as shown in FIG. 3, the fourth branch extension region 228 is folded toward the -Z side such that a valley fold crease is formed on the first surface 22a side along the seventh imaginary line 228a shown in FIG. 2. In FIG. 3, the fourth temperature detection element 254 is oriented toward the +X side. Next, the fourth branch extension region 228 is folded toward the +X side such that a mountain fold crease is formed on the first surface 22a side along the eighth imaginary line 228b shown in FIG. 3. By folding the fourth branch extension region 228 toward the +X side with the seventh imaginary line 228a and the eighth imaginary line 228b as creases, the fourth temperature detection element 254 is oriented toward the +Z side.

[0045] In the embodiment, the fourth branch extension region 228 is folded relative to the first main portion extension region 221 such that the fourth temperature detection element 254 contacts or approaches the -Z side portion of the battery cell 10. Therefore, compared with a case where members such as the fourth branch extension region 228 and the fourth support plate 264 exist between the -Z side portion of the battery cell 10 and the fourth temperature detection element 254, the temperature of the battery cell 10 can be accurately detected by the fourth temperature detection element 254.

[0046] The folding of the fourth branch extension region 228 is not limited to the above example as long as the fourth branch extension region 228 is folded toward the +X side such that the fourth temperature detection element 254 is oriented toward the +Z side.

[0047] In the embodiment, as shown in FIG. 2, in a state where the flexible substrate 22 is unfolded, a plurality of electrical components including the plurality of voltage detection terminals 23, the connector 24, the first temperature detection element 251, the second temperature detection element 252, the third temperature detection element 253, and the fourth temperature detection element 254 are located on the first surface 22a side, which is the same surface side of the flexible substrate 22. Therefore, compared with a case where some electrical components are located on the first surface 22a side of the flexible substrate 22 and other electrical components are located on the second surface 22b side of the flexible substrate 22, the mounting of the plurality of electrical components on the flexible substrate 22 can be facilitated. The electrical components located on the first surface 22a side of the flexible substrate 22 are not limited to the plurality of voltage detection terminals 23, the connector 24, the first temperature detection element 251, the second temperature detection element 252, the third temperature detection element 253, and the fourth temperature detection element 254.

[0048] Fig. 4 is a plan view of a film 22A from which a plurality of flexible substrates 22 according to the embodiment are cut out.

[0049] As shown in Fig. 4, the plurality of flexible substrates 22 may be cut out from the film 22A. In the example shown in Fig. 4, the plurality of flexible substrates 22 are arranged in a matrix having a plurality of rows in the Z direction and a plurality of columns in the Y direction.

[0050] After the plurality of flexible substrates 22 are cut out from the film 22A, portions between the flexible substrates 22 adjacent to each other in the Y direction of the film 22A and portions between the flexible substrates 22 adjacent to each other in the Z direction of the film 22A are discarded. From the viewpoint of the cost of the flexible substrates 22, it is desirable that the discarded portions of the film 22A are as small as possible. In the embodiment, the first main portion extension region 221, the third main portion extension region 223, the first support portion extension region 225, the second support portion extension region 226, the third support portion extension region 227, and the fourth support portion extension region 228 extend in substantially the same direction, that is, in the Y direction in the example shown in Fig. 4. Therefore, in the embodiment, compared with a case where the flexible substrate 22 obtained by projecting the shape of the flexible substrate 22 shown in, for example, Fig. 3 is cut out from the film 22A, the discarded portions of the film 22A can be reduced.

[0051] Fig. 5 is a developed view of the flexible substrate 22 according to Modification 1. Fig. 6 is a view for explaining bending of the flexible substrate 22 according to Modification 1. The flexible substrate 22 according to Modification 1 is the same as the flexible substrate 22 according to the embodiment except for the following points.

[0052] As shown in Figure 5, the third branch extension region 227 includes the second oblique extension region 227p and the third transverse extension region 228q. The second oblique extension region 227p branches off from approximately the center of the +Z side of the first main extension region 221 in the Y direction and extends obliquely to the +Z side with respect to the -Y direction. The second transverse extension region 227q extends from the -Y side end of the second oblique extension region 227p toward the -Y side. The fourth branch extension region 228 includes the third oblique extension region 228p and the third transverse extension region 228q. The third oblique extension region 228p branches off from the -Y side end of the +Z side of the first main extension region 221 and extends obliquely to the +Z side with respect to the +Y direction. The third transverse extension region 228q extends from the +Y side end of the third oblique extension region 228p toward the +Y side.

[0053] Referring to Figures 5 and 6, the assembly of the flexible substrate 22 to the voltage detection device 20 in Modification 1 will be described.

[0054] In Modification 1, the first branch extension region 225 and the second branch extension region 226 are folded in the same manner as described in the embodiment.

[0055] The folding of the third branch extension region 227 will now be explained. First, as shown in Figure 6, the third branch extension region 227 is folded to the -Z side so that a valley fold is formed along the fifth imaginary line 227a shown in Figure 5 on the first surface 22a side. In Figure 7, the third temperature detection element 253 is oriented to the +X side. Next, the second transverse extension region 227q is folded to the +X side so that a mountain fold is formed along the sixth imaginary line 227b shown in Figure 6 on the second surface 22b side. By folding the second transverse extension region 227q to the +X side using the fifth imaginary line 227a and the sixth imaginary line 227b as creases, the third temperature detection element 253 is oriented to the +Z side.

[0056] In Modification 1, the third branch extension region 227 is bent relative to the first main extension region 221 so that the third temperature detection element 253 contacts or is close to the -Z side portion of the battery cell 10. Therefore, compared to the case where a member such as the third branch extension region 227 or the third support plate 263 is present between the -Z side portion of the battery cell 10 and the third temperature detection element 253, the temperature of the battery cell 10 can be accurately detected by the third temperature detection element 253.

[0057] The bending of the third branch extension region 227 is not limited to the above example, as long as the third branch extension region 227 is bent towards the +X side so that the third temperature detection element 253 is oriented towards the +Z side.

[0058] The folding of the fourth branch extension region 228 will now be explained. First, as shown in Figure 6, the fourth branch extension region 228 is folded to the -Z side so that a valley fold is formed along the seventh imaginary line 228a shown in Figure 5 on the first surface 22a side. In Figure 6, the fourth temperature detection element 254 is oriented to the +X side. Next, the fourth branch extension region 228 is folded to the +X side so that a mountain fold is formed along the eighth imaginary line 228b shown in Figure 6 on the second surface 22b side. By folding the fourth branch extension region 228 to the +X side using the seventh imaginary line 228a and the eighth imaginary line 228b as creases, the fourth temperature detection element 254 is oriented to the +Z side.

[0059] In Modification 1, the fourth branch extension region 228 is bent relative to the first main extension region 221 so that the fourth temperature detection element 254 contacts or is close to the -Z side portion of the battery cell 10. Therefore, compared to the case where a member such as the fourth branch extension region 228 or the fourth support plate 264 is present between the -Z side portion of the battery cell 10 and the fourth temperature detection element 254, the temperature of the battery cell 10 can be accurately detected by the fourth temperature detection element 254.

[0060] The bending of the fourth branch extension region 228 is not limited to the above example, as long as the fourth branch extension region 228 is bent to the +X side so that the fourth temperature detection element 254 is oriented to the +Z side.

[0061] In the modified example 1 shown in Figure 5, when the flexible substrate 22 is unfolded, the third branch extension region 227 and the fourth branch extension region 228 are located between the -Z side of the first main extension region 221 and the +Z side of the third main extension region 223 in the projection of the flexible substrate 22 onto a plane perpendicular to the Y direction. In the embodiment shown in Figure 2, when the flexible substrate 22 is unfolded, the third branch extension region 227 and the fourth branch extension region 228 are located on the -Z side, outside the -Z side of the first main extension region 221. When cutting the flexible substrate 22 from the film, the portion of the flexible substrate 22 between the +Z side end and the -Z side end that does not constitute the flexible substrate 22 is discarded. Therefore, in the modified example, compared to the embodiment, the amount of film discarded between the +Z side end and the -Z side end of the flexible substrate 22 when cutting the flexible substrate 22 from the film can be reduced.

[0062] Figure 7 is an unfolded view of the flexible substrate 22 according to Modification 2. The flexible substrate 22 according to Modification 2 is the same as the flexible substrate 22 according to the embodiment, except for the following points.

[0063] As shown in Figure 7, the fourth branch extension region 228 branches off from the -Y side end of the +Z side of the first main extension region 221 and extends toward the +Z side. In the modified example 2, the fourth branch extension region 228 is folded toward the +X side so that a mountain fold is formed on the first surface 22a side along the seventh imaginary line 228a shown in Figure 7, thereby orienting the fourth temperature detection element 254 toward the +Z side. In the modified example 2 as well, the temperature of the battery cell 10 can be accurately detected by the fourth temperature detection element 254, compared to the case where there are members such as the fourth branch extension region 228 or the fourth support plate 264 between the -Z side portion of the battery cell 10 and the fourth temperature detection element 254.

[0064] The embodiments and modifications of the present invention have been described above with reference to the drawings, but these are merely examples of the present invention, and various other configurations can also be adopted.

[0065] In the embodiments and modifications, the battery cell 10 is the object of measurement for the temperature detection element. The matters described in the embodiments and modifications are also applicable to objects of measurement other than the battery cell 10. The matters described regarding the temperature detection element in the embodiments and modifications are applicable not only to the voltage detection device 20 but also to electronic devices other than the voltage detection device 20.

[0066] This application claims priority based on Japanese Patent Application No. 2025-051849, filed on 26 March 2025, and incorporates all of its disclosures herein.

[0067] 1 Battery module, 10 Battery cell, 11 Outer casing, 12 Positive terminal, 13 Negative terminal, 14 Terminal group, 20 Voltage detection device, 21 Protector, 211 Opening, 212 Boss, 22 Flexible substrate, 22a First surface, 22b Second surface, 22A Film, 221 First main extension region, 222 Second main extension region, 223 Third main extension region, 224 Fourth main extension region, 225 First branch extension region, 225a First virtual line, 225b Second virtual line, 226 Second branch extension region, 226a Third virtual line, 226b Fourth virtual line, 226p First oblique extension region, 226q First transverse extension region, 227 Third branch extension region, 227a Fifth virtual line, 227b Sixth virtual line, 227p Second oblique extension region, 227q Second transverse extension region, 228 Fourth branch extension region, 228a Seventh virtual line, 228b Eighth virtual line, 228p Third oblique extension region, 228q Third transverse extension region, 23 Voltage detection terminal, 24 Connector, 251 First temperature detection element, 252 Second temperature detection element, 253 Third temperature detection element, 254 Fourth temperature detection element, 261 First support plate, 262 Second support plate, 263 Third support plate, 264 Fourth support plate, 30 Bus bar

Claims

1. A voltage detection device for detecting the voltage of a battery cell, comprising: a flexible substrate; and a temperature detection element electrically connected to the flexible substrate, wherein the portion of the flexible substrate on which the temperature detection element is located is bent relative to the other portion of the flexible substrate so that the temperature detection element contacts or is in close proximity to the battery cell.

2. The voltage detection device according to claim 1, further comprising an electrical component located on the other part of the flexible substrate, wherein the temperature detection element and the electrical component are located on the same side of the flexible substrate when the flexible substrate is unfolded.

3. The voltage detection device according to claim 2, wherein the electrical component comprises at least one of a voltage detection terminal electrically connected to the battery cell and a connector electrically connected to the voltage detection terminal.

4. The voltage detection device according to claim 2 or 3, wherein the portion and the other portion of the flexible substrate extend at least partially in substantially the same direction.

5. A battery module comprising the battery cell and the voltage detection device according to any one of claims 1 to 4.

6. An electronic device comprising a flexible substrate and a temperature sensing element electrically connected to the flexible substrate, wherein the portion of the flexible substrate on which the temperature sensing element is located is bent relative to the other portion of the flexible substrate such that the temperature sensing element contacts or is in close proximity to the object to be measured by the temperature sensing element.

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