Battery module

Abstract

This battery module is disposed in an accommodation space in which an intermediate busbar is formed on a side surface of a stacked cell. A sensor unit includes: a sensor case that is accommodated in the accommodation space so as to contact the intermediate busbar; and a first clip that is electrically connected to a sensor circuit inside the sensor case, that is disposed at a position opposing the intermediate busbar in the sensor case when the sensor case is accommodated in the accommodation space, and that can be fitted to the intermediate busbar. By fitting the first clip to the intermediate busbar, the sensor case is secured to the intermediate busbar and the sensor circuit is electrically connected to the intermediate busbar via the first clip.

Description

[Technical Field]

[0001] The present invention relates to a battery module. [Background technology]

[0002] JP2021-18133A discloses a configuration in which a sensor unit that monitors the state of a battery cell is attached to a stacked cell in which multiple battery cells are stacked. Summary of the Invention

[0003] However, in JP2021-18133A, when attaching the sensor unit to the stacked cell, a wiring connection operation is required to connect the sensor unit's wiring to the stacked cell's electrodes, which increases the number of parts and assembly steps. Furthermore, the wiring removal operation during reuse / recycling is cumbersome. Furthermore, measures to prevent short circuits in the stacked cell are required during the wiring connection and removal operations. Furthermore, if the sensor unit is designed to be optimized for vehicle use, a new sensor unit with new specifications must be installed when the stacked cell is separated and reused for secondary use of the battery cell, and the above-mentioned problems arise again at that time.

[0004] An object of the present invention is to provide a battery module in which a sensor unit can be attached to a stacked cell while avoiding the need for complicated wiring connection and removal work and also for short circuit prevention measures.

[0005] A battery module according to the present invention is a battery module comprising a stacked cell in which a plurality of battery cells are stacked, a bus bar connected to the battery cells, and a sensor unit electrically connected to the bus bar and including a sensor circuit for measuring the state of the battery cells. Including a staircase-shaped busbar with two or more steps,The sensor unit is disposed in a housing space formed on one side of the laminated cell, and includes a sensor case that houses a sensor circuit and is formed to follow the shape of the bus bar and is housed in the housing space so as to contact the bus bar, and a fitting portion that is electrically connected to the sensor circuit, is located on the sensor case at a position facing the bus bar when the sensor case is housed in the housing space, and can be fitted with the bus bar. By fitting the fitting portion with the bus bar, the sensor case is fixed to the bus bar and the sensor circuit is electrically connected to the bus bar via the fitting portion. [Brief explanation of the drawings]

[0006] [Figure 1] FIG. 1 is a perspective view of a stacked cell that constitutes a battery module of this embodiment. [Figure 2] FIG. 2 is a diagram showing an area in the storage space formed in the stacked cell where a sensor unit or the like can be attached. [Figure 3] FIG. 3 is an exploded perspective view of the battery module of this embodiment. [Figure 4A] FIG. 4A is a perspective view of a sensor unit that constitutes the battery module of this embodiment. [Figure 4B] FIG. 4B is a cross-sectional view of a sensor portion constituting the battery module of this embodiment. [Figure 5] FIG. 5 is a cross-sectional view showing a connection state of the sensor unit. [Figure 6] FIG. 6 is a detailed view of a portion of FIG. [Figure 7] FIG. 7 is a circuit diagram of the sensor unit, battery cells, positive bus bars, negative bus bars, and intermediate bus bars. [Figure 8] FIG. 8 is a perspective view of a first modified example of the battery module of the present embodiment. [Figure 9A] FIG. 9A is a plan view of a sensor power supply unit of a first modified example. [Figure 9B] FIG. 9B is a cross-sectional view of the sensor power supply unit of the first modified example before it is sandwiched between the positive bus bar and the negative bus bar. [Figure 9C]FIG. 9C is a cross-sectional view of the sensor power supply unit of the first modified example after it has been sandwiched between the positive bus bar and the negative bus bar. [Figure 9D] FIG. 9D is a cross-sectional view of the sensor power supply unit of the first modified example when fixed with a clip. [Figure 10] FIG. 10 is a circuit diagram of the sensor unit, battery cell, positive bus bar, negative bus bar, intermediate bus bar, and sensor power supply unit of the first modified example. [Figure 11] FIG. 11 is a diagram showing an example of a jumper wire extending from the sensor unit. [Figure 12] FIG. 12 is a diagram showing an example of a clip attached to the sensor case. [Figure 13] FIG. 13 is a circuit diagram of a sensor unit, battery cells, positive bus bars, negative bus bars, and intermediate bus bars in a second modified example of the battery module of this embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0007] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

[0008] [Configuration of stacked cell 1] FIG. 1 is a perspective view of a stacked cell 1 that constitutes a battery module of this embodiment. In this embodiment, the stacked cell 1 is formed by stacking multiple (for example, four) battery cells 11 (S1, S2, S3, S4). The battery cell 11 has a power storage section 111 formed of, for example, a lithium ion battery, and fastening sections 112 disposed at both ends of the two long sides (or short sides) of the power storage section 111. The stacked cell 1 is then formed by stacking the battery cells 11 and fastening the fastening sections 112, for example, by crimping.

[0009] Thin plate portions 12 are arranged at positions sandwiched between two fastening portions 112 in the battery cells 11 at both ends in the thickness direction of the stacked cell 1. The area surrounded by the fastening portions 112 and the thin plate portions 12 forms an accommodation space 14 that accommodates a positive electrode bus bar 2, a negative electrode bus bar 3, an intermediate bus bar 4, a sensor unit 5 (FIG. 3), and the like, which will be described later.

[0010] The battery cell 11 has a positive electrode cell tab 113 that extends from the positive electrode of the storage unit 111 and is placed in the storage space 14, and a negative electrode cell tab 114 that extends from the negative electrode of the storage unit 111 and is placed in the storage space 14.

[0011] The positive bus bar 2 has a positive external terminal P for connection to the outside, and is connected to the positive cell tab 113 (P1) of the bottom battery cell 11 (S1) shown in Fig. 1 and the positive cell tab 113 (P2) of the second-lowest battery cell 11 (S2) in order of electrical proximity from the positive external terminal P (Fig. 7). The positive bus bar 2 is also supported by the positive cell tab 113 (P1) and the positive cell tab 113 (P2).

[0012] The negative bus bar 3 has a negative external terminal N for connection to the outside, and is connected to the negative cell tab 114(N3) of the second battery cell 11(S3) from the top shown in Fig. 1 and the negative cell tab 114(N4) of the top battery cell 11(S4) (not shown in Fig. 1, see Fig. 3) in order of electrical proximity from the negative external terminal N (Fig. 7). The negative bus bar 3 is also supported by the negative cell tab 114(N3) and the negative cell tab 114(N4).

[0013] The intermediate bus bar 4 has an intermediate external terminal M for connection to the outside, and is connected to the negative electrode cell tab 114(N1) of the battery cell 11(S1), the negative electrode cell tab 114(N2) of the battery cell 11(S2), the positive electrode cell tab 113(P3) of the battery cell 11(S3), and the positive electrode cell tab 113(P4) of the battery cell 11(S4) in order of electrical proximity to the intermediate external terminal M (FIG. 7). The intermediate bus bar 4 is also supported by the negative electrode cell tab 114(N1), the negative electrode cell tab 114(N2), the positive electrode cell tab 113(P3), and the positive electrode cell tab 113(P4).

[0014] With the above connection configuration, the positive electrode of the battery cell 11(S1) and the positive electrode of the battery cell 11(S2) are connected in parallel by the positive electrode bus bar 2, and the positive electrode of the battery cell 11(S1) and the positive electrode of the battery cell 11(S2) become the positive electrodes of the stacked cell 1 (Fig. 7). Also, the negative electrode of the battery cell 11(S3) and the negative electrode of the battery cell 11(S4) are connected in parallel by the negative electrode bus bar 3, and the negative electrode of the battery cell 11(S3) and the negative electrode of the battery cell 11(S4) become the negative electrodes of the stacked cell 1 (Fig. 7). Furthermore, the negative electrode of the battery cell 11(S1), the negative electrode of the battery cell 11(S2), the positive electrode of the battery cell 11(S3), and the positive electrode of the battery cell 11(S4) are connected in parallel to the intermediate bus bar 4 (Fig. 7).

[0015] The positive bus bar 2, the negative bus bar 3, and the intermediate bus bar 4 are bent in a stepped shape within the accommodation space 14 so as to be connected to the respective cell tabs but not to come into contact with the other bus bars.

[0016] In addition, stoppers 141 are arranged in the accommodation space 14 close to the bus bars, and when the bus bars vibrate relative to the stacked cells 1 due to external vibrations, the bus bars are brought into preferential contact with the stoppers 141, preventing the bus bars from coming into contact with other bus bars.

[0017] 2 is a diagram showing an area in the accommodation space 14 formed in the stacked cell 1 where the sensor unit 5 and the like can be attached. As shown in FIG. 2, the accommodation space 14 is formed with a plurality of divided spaces (a first divided space 142, a second divided space 143, and a third divided space 144) (areas surrounded by thick lines) separated by the positive bus bar 2, the negative bus bar 3, and the intermediate bus bar 4. In this embodiment, the sensor unit 5, which will be described later, is disposed in the first divided space 142, but can also be disposed in the second divided space 143 or the third divided space 144.

[0018] For example, if the accommodation space 14 is divided into many parts by the bus bars (positive bus bar 2, negative bus bar 3, intermediate bus bar 4), the sensor unit 5 (sensor circuit 52 described below) is divided into multiple parts, and the same number of split sensor cases (sensor cases 51 described below) as the number of sensor units 5 are prepared, and each split sensor case (sensor case 51) houses a split sensor circuit (sensor circuit 52 described below) and is arranged in the accommodation space 14. In this way, multiple small-sized split sensor cases (sensor cases 51) are arranged in the accommodation space 14, and they can be arranged so as not to interfere with the bus bars, thereby increasing the degree of freedom in designing the battery module.

[0019] [Battery module configuration] 3 is an exploded perspective view of the battery module of this embodiment. The battery module of this embodiment includes the stacked cell 1, the sensor unit 5, the sub-circuit unit 6, and the terminal cover 7 (cover). In the battery module of this embodiment, the sensor unit 5 and the sub-circuit unit 6 are disposed in the accommodation space 14, and the terminal cover 7 is fitted to the side of the stacked cell 1 so as to cover the accommodation space 14 (the sensor unit 5, the sub-circuit unit 6).

[0020] The sensor unit 5 is disposed in the accommodation space 14, for example, in a first divided space 142 (FIG. 2) formed between the thin plate portion 12 and the intermediate bus bar 4, and has a sensor case 51 whose outer shape follows the shape of the first divided space 142, i.e., the stepped shape of the intermediate bus bar 4. In FIG. 3, the number of steps on the surface of the sensor case 51 facing the intermediate bus bar 4 can be set arbitrarily depending on the number of connections between the sensor circuit 52 and the cell tabs. The sensor case 51 only needs to have a shape that allows it to be fitted into at least the stepped first divided space partitioned by the intermediate bus bar 4. A sensor circuit 52 (FIG. 4B) that detects, for example, the state (output voltage, internal resistance) of the battery cell 11 is disposed within the sensor case 51.

[0021] Conductive first clips 53 are arranged at positions facing each stage (where cell tabs are arranged) of the intermediate bus bar 4 of the sensor case 51. The first clips 53 are leaf spring contacts made of, for example, phosphor bronze, and have appropriate elasticity and electrical conduction resistance.

[0022] The first clip 53 is electrically connected to the sensor circuit 52 (FIG. 4B). The intermediate bus bar 4 (and the cell tabs) are sandwiched between the first clip 53 and the sensor case 51, and the sensor case 51 is fixed to the intermediate bus bar 4 (cell tabs) by applying a pressing force of the first clip 53 to the intermediate bus bar 4, and the sensor circuit 52 and the intermediate bus bar 4 (cell tabs) are electrically connected to each other via the first clip 53.

[0023] The outer shape of sensor case 51 may be designed to be slightly larger than first divided space 142 formed between thin plate portion 12 and intermediate bus bar 4, and sensor case 51 may be disposed in first divided space 142 in such a manner that it is pressed into first divided space 142. This fixes sensor case 51 to first divided space 142 by the pressing force of first clip 53 and the pressing force of sensor case 51 against intermediate bus bar 4, thereby reducing the burden on first clip 53 (the same applies to sub-circuit portion 6 described below).

[0024] A first connection terminal 521 is disposed on the surface of the sensor case 51 facing the terminal cover 7. The first connection terminal 521 is used, for example, as a power input terminal for supplying power to the sensor circuit 52, a terminal for bidirectional communication with the sub-circuit unit 6, etc. The first connection terminal 521 is disposed so as to protrude from the sensor case 51 toward the terminal cover 7, and abuts against the second wiring 73 disposed on the inner wall of the terminal cover 7 when the terminal cover 7 is fitted into the stacked cell 1. Note that the first connection terminal 521 preferably has a structure similar to that of the first clip 53, and is deformed by receiving a pressing force from the terminal cover 7, and is configured to be able to apply the restoring force generated by the deformation to the terminal cover 7 (first wiring 72). This ensures electrical connection between the first connection terminal 521 and the first wiring 72.

[0025] The sub-circuit section 6 is arranged in the accommodation space 14, for example, in a second divided space 143 (Figure 2) formed between the positive bus bar 2 and the negative bus bar 3, and has a circuit case 61 (corresponding to a holder 61a described below) whose outer shape follows the shape of the second divided space 143.

[0026] The sub-circuits 62 (Fig. 7) arranged within the circuit case 61 are intended to assist the sensor circuit 52, such as a sensor power supply circuit 62a (Figs. 9A, 9B, 9C, and 9D) that supplies power to the sensor unit 5, and a BLE (Bluetooth (registered trademark) Low Energy) type sensor communication circuit that communicates information obtained by the sensor circuit 52 with the outside in two directions.

[0027] A second clip 63 is disposed at a position facing the positive bus bar 2 of the circuit case 61, and a third clip 64 is disposed at a position facing the negative bus bar 3 of the circuit case 61. The second clip 63 and the third clip 64 have the same structure as the first clip 53.

[0028] The second clip 63 is electrically connected to the sub-circuit 62 (FIGS. 7, 9A, 9B, 9C, and 9D). The positive bus bar 2 is sandwiched between the second clip 63 and the circuit case 61, and the pressing force of the second clip 63 is applied to the circuit case 61 and the positive bus bar 2, thereby fixing the circuit case 61 to the positive bus bar 2 and electrically connecting the sub-circuit 62 to the positive bus bar 2 via the second clip 63.

[0029] The third clip 64 is electrically connected to the sub-circuit 62 (FIGS. 7, 9A, 9B, 9C, and 9D), similarly to the second clip 63. The negative bus bar 3 is sandwiched between the third clip 64 and the circuit case 61, and the pressing force of the third clip 64 is applied to the circuit case 61 and the negative bus bar 3, thereby fixing the circuit case 61 to the negative bus bar 3 and electrically connecting the sub-circuit 62 to the negative bus bar 3 via the third clip 64.

[0030] A second connection terminal 622 is arranged on the surface of the circuit case 61 facing the terminal cover 7. The second connection terminal 622 is used, for example, as a power output terminal for supplying power to the sensor circuit 52, a terminal for bidirectional communication with the sensor circuit 52, etc.

[0031] The second connection terminal 622 has a similar structure to the first connection terminal 521 and is arranged so as to protrude from the circuit case 61 toward the terminal cover 7, and abuts against the first wiring 72 arranged on the inner wall of the terminal cover 7 when the terminal cover 7 is fitted into the stacked cell 1.

[0032] The terminal cover 7 is a member having an inner wall that contacts the outer walls of the two thin plate portions 12 of the stacked cell 1. The terminal cover 7 is formed of an electrically insulating material that has magnetic properties, similar to the sensor case 51, as will be described later, and its surface is covered with an insulating layer (not shown) such as resin.

[0033] By inserting the terminal cover 7 through the opening of the accommodation space 14, the terminal cover 7 is attached to the stacked cell 1 so as to cover the accommodation space 14.

[0034] The terminal cover 7 has insertion holes 71 into which the positive external terminal P, the negative external terminal N, and the intermediate external terminal M are inserted, and when the terminal cover 7 is attached to the stacked cell 1, each external terminal is positioned within the insertion hole 71.

[0035] Furthermore, a first wiring 72 and a second wiring 73 are arranged on an insulating layer (not shown) on the inner wall of the terminal cover 7. Meanwhile, a third wiring 131 is arranged on the outer wall of the thin plate portion 12, extending in a direction connecting the pair of fastening portions 112 and extending at one end in a direction toward the first connection terminal 521 of the sensor case 51 in a plan view and at the other end in a direction toward the second connection terminal 622 of the sub-circuit unit 6. The first wiring 72, the second wiring 73, and the third wiring 131 are all formed of, for example, Cu (copper) tape.

[0036] When the terminal cover 7 is attached to the stacked cell 1, one end of the first wiring 72 is Second connection terminal 622 and the other end is disposed at a position facing the third wiring 131.

[0037] When the terminal cover 7 is attached to the stacked cell 1, one end of the second wiring 73 is First connection terminal 521 and the other end is disposed at a position facing the third wiring 131.

[0038] Therefore, when the terminal cover 7 is attached to the stacked cell 1, one end of the first wiring 72 contacts the second connection terminal 622 and the other end contacts the third wiring 131. Also, one end of the second wiring 73 contacts the first connection terminal 521 and the other end is connected to the third wiring 131. As a result, the first connection terminal 521 and the second connection terminal 622 are electrically connected to each other via the first wiring 72, the second wiring 73, and the third wiring 131. Note that the third wiring 131 is omitted and only a partial view of the first wiring 72 is shown in FIG. 3 As shown in (terminal cover 7 shown in the area surrounded by a dashed rectangular line), a fourth wiring 74 may be arranged on the inner wall of terminal cover 7, connecting first wiring 72 and second wiring 73 to each other.

[0039] For example, if the sensor circuit 52 in the sensor unit 5 and the sub-circuit 62 in the sub-circuit unit 6 (Figures 7, 9A, 9B, 9C, and 9D) are capable of bidirectional wireless communication, and the sensor circuit 52 has a built-in small battery and does not require external power supply, the first connection terminal 521, the second connection terminal 622, the first wiring 72, the second wiring 73, the third wiring 131, and the fourth wiring 74 can be omitted.

[0040] [Sensor section] Fig. 4A is a perspective view of the sensor unit 5 constituting the battery module of this embodiment. Fig. 4B is a cross-sectional view of the sensor unit 5 constituting the battery module of this embodiment. Fig. 4A shows the sensor unit 5 attached to the intermediate bus bar 4.

[0041] As shown in Fig. 4A, the intermediate bus bar 4 has a four-step staircase shape, and each step is provided with a cell tab extending from a battery cell 11. For example, from the top of Fig. 4A, the cell tabs provided on the intermediate bus bar 4 are the positive electrode cell tab 113(P4) of the battery cell 11(S4), the positive electrode cell tab 113(P3) of the battery cell 11(S3), the negative electrode cell tab 114(N2) of the battery cell 11(S2), and the negative electrode cell tab 114(N1) of the battery cell 11(S1).

[0042] The sensor case 51 (as well as the circuit case 61) is made of an electrically insulating material having magnetic properties, and can provide electrostatic shielding for the inside of the case.

[0043] Here, the sensor case 51 is made by sheet metal or press processing of a metal material with high magnetic permeability, such as an iron plate or steel plate, or by die casting or hot pressing of resin mixed with magnetic powder. Then, an insulating layer is formed by applying resin or the like to the inner wall of the sensor case 51. Furthermore, the sensor case 51 may be made of resin, and its outer wall may be coated with magnetic paint.

[0044] Examples of electrically insulating materials having magnetic properties include high-performance soft magnetic powders (DAPM3, DAPMS7, DAPMSA10, DAPMSC, etc.) manufactured by Daido Steel Co., Ltd., metallic glass magnetic powder (SAP-2D) and metallic soft magnetic powder (FSC2K) manufactured by Shinto Kogyo Co., Ltd., and metallic soft magnetic materials (flat metal powder, metallic injection molding material, magnetic sheet) manufactured by Mate Co., Ltd.

[0045] 4B, the sensor circuit 52 and an extraction electrode 522 extracted from the sensor circuit 52 are arranged inside the sensor case 51. The extraction electrode 522 is made by attaching copper foil (having an insulating layer on the sensor case 51 side) to the sensor case 51.

[0046] As shown in FIGS. 4A and 4B, sensor case 51 has insertion hole 511 through which one arm of first clip 53 is inserted.

[0047] 4A, the first clip 53 can be initially separated from the sensor case 51. Then, with the two arms of the first clip 53 slightly open, one arm is inserted into the insertion hole 511 and the other arm of the first clip 53 is brought into contact with the cell tab. As a result, the elastic force of the first clip 53 in the direction of closing the arms simultaneously clamps the cell tabs (positive electrode cell tab 113, negative electrode cell tab 114), intermediate bus bar 4, sensor case 51, and extraction electrode 522.

[0048] As a result, the sensor case 51 is fixed to the intermediate bus bar 4 by the first clip 53. Furthermore, the extraction electrodes 522 of the sensor circuit 52 are electrically connected to the cell tabs (positive electrode cell tab 113, negative electrode cell tab 114) via the first clip 53.

[0049] The first clip 53 can be directly joined to the cell tabs (positive electrode cell tab 113, negative electrode cell tab 114) by, for example, ultrasonic welding, which prevents the sensor circuit 52 from detecting the resistance component of the bus bar.

[0050] The sensor circuit 52 can be formed in any shape. For example, two rigid substrates 52a and 52b can be formed into a flexible substrate. 52c 4B, it is also preferable to arrange the lead-out electrode 522 on a flexible substrate connected to the substrate 52a or 52b, and to arrange the substrate in a position opposite the insertion hole 511.

[0051] Four jumper wires 54 (only one shown in FIG. 4A) connected to the sensor circuit 52 extend from the side of the sensor case 51, and a fourth clip 542 (which can have the same structure as the first clip 53) is attached to the tip of the jumper wire 54. The fourth clip 542 can be attached to, for example, the position where the positive electrode cell tab 113 (P1) of the battery cell 11 (S1) is arranged on the positive electrode bus bar 2, the position where the positive electrode cell tab 113 (P2) of the battery cell 11 (S2) is arranged on the positive electrode bus bar 2, the position where the negative electrode cell tab 114 (N3) of the battery cell 11 (S3) is arranged on the negative electrode bus bar 3, the position where the negative electrode cell tab 114 (N4) of the battery cell 11 (S4) is arranged on the negative electrode bus bar 3, the position where the positive electrode cell tab 113 (P5) of the battery cell 11 (S5) is arranged on the negative electrode bus bar 3, the position where the negative electrode cell tab 114 (N6) of the battery cell 11 (S6) is arranged on the negative electrode bus bar 3, the position where the positive electrode cell tab 113 (P7) of the battery cell 11 (S7) is arranged on the negative electrode bus bar 3, the position where the negative electrode cell tab 114 (N8) of the battery cell 11 (S8) is arranged on the negative electrode bus bar 3, the position where the positive electrode cell tab 113 (P9) of the battery cell 11 (S9) is arranged on the positive electrode bus bar 2, the position where the negative electrode cell tab 114 (N9) of the battery cell 11 (S1) is arranged on the positive electrode bus bar 2, the position where the negative electrode cell tab 114 (N1) of the battery cell 11 (S1) is arranged on the positive electrode bus bar 2, the position N4 The bus bars are clamped at the position where the negative electrode cell tab 114 (S4) of the positive electrode cell tab 113 and the negative electrode cell tab 114 are located. As a result, the sensor circuit 52 is electrically connected to each cell tab (positive electrode cell tab 113, negative electrode cell tab 114) via the jumper wire 54 (fourth clip 542).

[0052] [Connection status of sensor unit 5] Fig. 5 is a cross-sectional view showing the connection state of the sensor unit 5. Fig. 6 is a partial detailed view of Fig. 5. As shown in Fig. 5, when the terminal cover 7 is attached to the stacked cell 1, each external terminal (negative external terminal N in the figure) is placed in the insertion hole 71 of the terminal cover 7.

[0053] Furthermore, the first connection terminal 521 arranged on the sensor case 51 contacts the second wiring 73, and the second wiring 73 contacts the third wiring 131. At this time, although not shown in the drawings, the second connection terminal 622 arranged on the circuit case 61 contacts the first wiring 72.

[0054] As described above, one arm of the first clip 53 is inserted into the insertion hole 511 formed in the sensor case 51, and simultaneously clamps the cell tabs (positive electrode cell tab 113, negative electrode cell tab 114), the intermediate bus bar 4, the sensor case 51, and the extraction electrode 522. At this time, there is a possibility that the first clip 53 may come into contact with the bus bar. If the first clip 53 comes into contact with the bus bar, the charge / discharge current will also flow through the first clip 53, and an excessive current will flow through the first clip 53, which is not designed to carry a large current, potentially causing heat generation or damage to the first clip 53. Alternatively, the detection signal input to the sensor circuit 52 will contain a resistance component of the bus bar, leading to a sensor error.

[0055] Therefore, an insulating layer 531 is disposed on the inner wall of the portion of the first clip 53 exposed from the sensor case 51, excluding the contact position with the cell tabs (positive electrode cell tab 113, negative electrode cell tab 114). The insulating layer 531 can be realized by attaching an electrical insulating tape such as polyimide or by resin coating, etc. This ensures electrical insulation between the first clip 53 and the bus bar.

[0056] Although not shown, the inner wall of the insertion hole 511 is also covered with an insulating layer, thereby ensuring electrical insulation between the sensor case 51 and the first clip 53.

[0057] When attaching the sensor unit 5 to the intermediate bus bar 4, the first clip 53 may be previously joined to the extraction electrode 522 by soldering or the like. Alternatively, an ultrasonically vibrating horn (not shown) may be pressed from the first clip 53 side against a contact position (indicated by an arrow in FIG. 6 ) with the cell tabs (positive electrode cell tab 113, negative electrode cell tab 114) of the first clip 53, thereby melting the first clip 53, the cell tabs (positive electrode cell tab 113, negative electrode cell tab 114), and the intermediate bus bar 4. This allows the first clip 53 to be connected to the cell tabs (positive electrode cell tab 113, negative electrode cell tab 114), and the cell tabs (positive electrode cell tab 113, negative electrode cell tab 114) to be connected to the intermediate bus bar 4. In this way, by connecting the first clip 53 directly to the cell tabs (positive electrode cell tab 113, negative electrode cell tab 114) without contacting the intermediate bus bar 4, it is possible to detect the state of the battery cell 11 with high accuracy without detecting the resistance component of the bus bar. The above connection configuration can be similarly applied to the sub-circuit unit 6.

[0058] [Circuit diagram] 7 is a circuit diagram of the sensor unit 5, battery cell 11, positive bus bar 2, negative bus bar 3, and intermediate bus bar 4. As shown in FIG. 7, the battery cell 11 (S1) and the battery cell 11 (S2) are connected in parallel between the positive bus bar 2 and the intermediate bus bar 4.

[0059] The positive side (positive electrode cell tab 113) of the battery cell 11 (S1) has a contact point (P1) on the positive electrode bus bar 2 that is closest to the positive electrode external terminal P, and the negative side (negative electrode cell tab 114) has a contact point (N1) on the intermediate bus bar 4 that is closest to the intermediate external terminal M.

[0060] The positive side (positive electrode cell tab 113) of the battery cell 11 (S2) has a contact point (P2) on the positive electrode bus bar 2 that is farthest from the positive electrode external terminal P, and the negative side (negative electrode cell tab 114) has a contact point (N2) on the intermediate bus bar 4 that is second closest to the intermediate external terminal M.

[0061] The battery cell 11 (S3) and the battery cell 11 (S3) are connected in parallel between the intermediate bus bar 4 and the negative bus bar 3.

[0062] The positive side (positive cell tab 113) of the battery cell 11 (S3) has a contact point (P3) on the intermediate bus bar 4 that is third closest to the intermediate external terminal M, and the negative side (negative cell tab 114) has a contact point (N3) on the negative bus bar 3 that is closest to the negative external terminal N.

[0063] The positive side (positive cell tab 113) of the battery cell 11 (S4) has the contact point (P4) on the intermediate bus bar 4 that is the farthest from the intermediate external terminal M, and the negative side (negative cell tab 114) has the contact point (N4) on the negative bus bar 3 that is the farthest from the negative external terminal N.

[0064] The sensor circuit 52 is connected to the contacts (N1), (N2), (P3), and (P4) by first clips 53 attached to the sensor case 51, respectively.

[0065] Furthermore, the sensor circuit 52 is connected to the contact (P1), the contact (P2), the contact (N3), and the contact (N4) by the jumper wire 54 (fourth clip 542).

[0066] Therefore, the sensor circuit 52 can detect the state of the battery cell 11 (S1) from the contacts (P1) and (N1), the state of the battery cell 11 (S2) from the contacts (P2) and (N2), the state of the battery cell 11 (S3) from the contacts (P3) and (N3), and the state of the battery cell 11 (S4) from the contacts (P4) and (N4).

[0067] [First Modification] FIG. 8 is a perspective view of a first modified example of the battery module of this embodiment. FIG. 9A is a plan view of a sensor power supply unit 6a of the first modified example. FIG. 9B is a cross-sectional view of the sensor power supply unit 6a of the first modified example before it is sandwiched between the positive bus bar 2 and the negative bus bar 3. FIG. 9C is a cross-sectional view of the sensor power supply unit 6a of the first modified example after it has been sandwiched between the positive bus bar 2 and the negative bus bar 3. FIG. 9D is a cross-sectional view of the sensor power supply unit 6a of the first modified example when secured with clips (second clip 63 and third clip 64). FIG. 10 is a circuit diagram of the sensor unit 5, battery cell 11, positive bus bar 2, negative bus bar 3, intermediate bus bar 4, and sensor power supply unit 6a of the first modified example. Note that the sensor unit 5 and terminal cover 7 are not shown in FIG. 8.

[0068] The sensor power supply unit 6a can be used to eliminate fluctuations in the voltage measured (AD converted) by the sensor circuit 52 when the voltage of the battery cell 11 changes depending on the state of charge (SOC).

[0069] The sensor power supply unit 6a includes an insulating holder 61a sandwiched between the positive bus bar 2 and the negative bus bar 3, a sensor power supply circuit 62a (Figure 9A) attached to the holder 61a, a first extraction electrode 623 (Figure 9A) electrically connected to the positive side of the sensor power supply circuit 62a, a second extraction electrode 624 (Figure 9A) electrically connected to the negative side of the sensor power supply circuit 62a, a second connection terminal 622 connected to the output side of the sensor power supply circuit 62a, a second clip 63, and a third clip 64.

[0070] As shown in FIG. 9A, the holder 61a has an L-shaped configuration on the side that contacts the negative bus bar 3 when viewed from above, but as shown in FIG. 9B, it has a U-shaped configuration when viewed from the cross-sectional direction (thickness direction of the stacked cell 1).

[0071] The sensor power supply circuit 62a is, for example, a portion extending in the thickness direction of the holder 61a, and is disposed on the back surface of the surface facing the terminal cover 7 (FIG. 3). It is efficient to connect the sensor power supply circuit 62a to the positive and negative terminals and input two voltages in series (2.5-4.2V x 2). Therefore, by mounting the sensor power supply circuit 62a in a position that allows it to be connected to the positive bus bar 2 and the negative bus bar 3 in the shortest distance, the lengths of the leaf spring-shaped second clip 63 and third clip 64, which serve as connection means (substitute for wiring), can be shortened, which is advantageous in terms of rigidity during mating and saving on material costs.

[0072] In the battery module shown in Figure 8, the negative bus bar 3 is close to the upper space of the positive bus bar 2, so if the sensor power supply circuit 62a is mounted in this upper space (second division space 143 (Figures 2 and 9B)), the lengths of the second clip 63 and the third clip 64 can be shortened, which is preferable.

[0073] In addition, since the influence of bus bar resistance on sensing can be ignored in the connection of the sensor power supply circuit 62a, the connection points of the second clip 63 and the third clip 64 may be bus bars or cell tabs.

[0074] Furthermore, when the upper surface of the holder 61a contacts the inner wall (thin plate portion 12) of the accommodation space 14 or the stopper 141, the holder 61a may be fixed with, for example, an elastic sheet, double-sided tape, modified silicone adhesive, etc. This is an effective fixing method for providing resistance to vibrations when mounted in a vehicle.

[0075] The connection mode between the second connection terminal 622 and the first connection terminal 521 (Figure 3) is the same as the mode shown in Figure 3, but as shown in Figure 10, the first connection terminal 521 and the second connection terminal 622 may be omitted and the power output terminal (OUT) of the sensor power supply circuit 62a and the power input terminal (IN) of the sensor circuit 52 may be directly connected by a jumper wire 65.

[0076] First extraction electrode 623 is disposed on the back side of the contact surface with positive bus bar 2 of holder 61a.

[0077] Second extraction electrode 624 is disposed on the back side of the contact surface of holder 61a with negative electrode bus bar 3, in a portion where the width is narrowed in the horizontal direction of FIG. 9A.

[0078] An insertion hole 66 is arranged on the first extraction electrode 623 side of the portion extending in the thickness direction of the holder 61a, and the first extraction electrode 623 is arranged at a position opposite the insertion hole 66.

[0079] 9B and 9C, the sensor power supply unit 6a is attached by sandwiching the holder 61a between the positive bus bar 2 and the negative bus bar 3. Then, as shown in FIGS. 9C and 9D, one arm of the second clip 63 is inserted into the insertion hole 66 and brought into contact with the first extraction electrode 623, and the other arm of the second clip 63 is brought into contact with the positive bus bar 2, thereby simultaneously sandwiching the positive bus bar 2, the holder 61a (on the positive bus bar 2 side), and the first extraction electrode 623 by the second clip 63. Similarly, as shown in FIGS. 9C and 9D, one arm of the third clip 64 is brought into contact with the second extraction electrode 624, and the other arm of the third clip 64 is brought into contact with the negative bus bar 3, thereby simultaneously sandwiching the negative bus bar 3, the holder 61a (on the negative bus bar 3 side), and the second extraction electrode 624 by the third clip 64.

[0080] By the above procedure, holder 61a (positive bus bar 2 side) is fixed to positive bus bar 2, and first extraction electrode 623 is electrically connected to positive bus bar 2 (contact point (P2)) via second clip 63 (FIG. 10). Also, holder 61a (negative bus bar 3 side) is fixed to negative bus bar 3, and second extraction electrode 624 is electrically connected to negative bus bar 3 (contact point (N4)) via third clip 64 (FIG. 10).

[0081] In some cases, the gap between the negative bus bar 3 and the inner wall of the accommodation space 14 is narrow, and when the second extraction electrode 624, holder 61a, and negative bus bar 3 (cell tab) are simultaneously clamped by the third clip 64, the third clip 64 may interfere with the inner wall of the accommodation space 14, making clamping difficult. In such cases, a tab (not shown) extending from the second extraction electrode 624 can be placed on the negative bus bar 3, and the tab (not shown) and the negative bus bar 3 (cell tab) can be clamped by the third clip 64. This widens the gap between the tab (not shown) and the inner wall of the accommodation space 14 by the amount corresponding to the reduction in the thickness of the holder 61a, making it easier to clamp the items with the third clip 64.

[0082] [Jumper wire, clip] Fig. 11 is a diagram showing an example of a jumper wire 54 extending from the sensor unit 5. Fig. 12 is a diagram showing an example of a clip (first clip 53) attached to the sensor case 51.

[0083] 11, jumper wire 54 includes flexibly deformable coated wiring 541 and fourth clip 542 disposed at the tip of coated wiring 541. Fourth clip 542 is connected to a conductive wire (copper wire) inside coated wiring 541. Fourth clip 542 is set so that the width between its two arms is slightly smaller than the combined thickness of the bus bar and the cell tab, allowing the bus bar and cell tab to be clamped between the two arms at the same time.

[0084] 12, the first clip 53 has a structure in which arms 533, 534 extend from both ends in the width direction of a base 532. The pair of arms 533, 534 are shaped so that the distance between them narrows as they move away from the base 532, and then the distance widens midway. The part of the arm 533 where the distance between the arm 534 is narrowest is the part that applies the greatest pressing force to the cell tabs (positive electrode cell tab 113, negative electrode cell tab 114) (FIG. 6).

[0085] Also, a flat portion 535 is formed at the center of the arm 534 that contacts the extraction electrode 522 (Figs. 5 and 6) and is arranged to stand substantially perpendicular to the base portion 532. Therefore, when the first clip 53 is attached to the sensor case 51, the flat portion 535 comes into surface contact with the extraction electrode 522, reducing the contact resistance between the extraction electrode 522 (Figs. 5 and 6) and the first clip 53.

[0086] [Second Modified Example] FIG. 13 is a circuit diagram of a second modified example of the battery module of the present embodiment, showing the sensor unit 5, the battery cell 11, the positive electrode bus bar 2, the negative electrode bus bar 3, and the intermediate bus bar 4.

[0087] The second modified example has a configuration for simply measuring the apparent internal resistance between the positive electrode external terminal P and the intermediate external terminal M (or between the intermediate external terminal M and the negative electrode external terminal N).

[0088] FIG. to 13 In this figure, when the resistance from the positive electrode external terminal P to the contact point (P1) on the positive electrode bus bar 2 is Rb, the resistance from the contact point (P1) to the contact point (P2) on the positive electrode bus bar 2 is Rb12, the resistance from the intermediate external terminal M to the contact point (N1) on the intermediate bus bar 4 is Rb, the resistance from the contact point (N1) to the contact point (N2) on the intermediate bus bar 4 is Rb12, the internal resistance of the battery cell 11 (S1) is Rc1, and the internal resistance of the battery cell 11 (S2) is Rc2, the apparent internal resistance Rpm between the positive electrode external terminal P and the intermediate external terminal M is expressed by the following equation (1).

Equation

[0089] The resistance of the bus bar is sufficiently small compared to the internal resistance Rc1 of the battery cell 11 (S1) and the internal resistance Rc2 of the battery cell 11 (S2). Therefore, Rb12 can be regarded as << Rc2, and in equation (1), Rb12 = 0 and Rc2 = Rc1 can be regarded. Thus, equation (1) can be simplified as the following equation (2).

number

[0090] Therefore, it is practical to configure the internal resistance of parallel-connected battery cells 11 so that it is detected by connecting it to one cell.

[0091] Strictly speaking, assuming that Rc1=Rc=2, due to differences in busbar resistance, a larger charge / discharge current flows through the battery cell 11(S1) that is closer to the positive external terminal P and the intermediate external terminal M. Therefore, from the perspective of diagnosing the degree of deterioration (SOH: State of Health) of the battery, it is appropriate to connect the sensor circuit 52 to the battery cell 11(S1), through which a larger charge / discharge current flows, out of the battery cell 11(S1) and the battery cell 11(S2).

[0092] Therefore, by detecting the internal resistance Rc1 of the battery cell 11 (S1) using the sensor circuit 52 and applying the internal resistance Rc1 to equation (2), the combined resistance with the battery cell 11 (S2), i.e., the internal resistance Rpm between the positive external terminal P and the intermediate external terminal M, can be calculated.

[0093] The above has been explained using the battery cells 11(S1) and 11(S2) as examples, but the same can also be applied to the battery cells 11(S3) and 11(S4) when calculating the internal resistance of the battery cells 11(S3) and 11(S4) as viewed from the intermediate external terminal M and the negative external terminal N. That is, by detecting the internal resistance of the battery cell 11(S3) using the sensor circuit 52 and applying this internal resistance to equation (2), it is possible to calculate the combined resistance with the battery cell 11(S4), i.e., the internal resistance between the intermediate external terminal M and the negative external terminal N.

[0094] [Effects of this embodiment] According to the battery module of this embodiment, the battery module includes a stacked cell 1 in which a plurality of battery cells 11 are stacked, bus bars (positive bus bar 2, negative bus bar 3, intermediate bus bar 4) connected to the battery cells 11, and a sensor unit 5 that is electrically connected to the bus bars and includes a sensor circuit 52 that measures the state of the battery cells. The bus bars (positive bus bar 2, negative bus bar 3, intermediate bus bar 4) are arranged in a storage space 14 formed on one side of the stacked cell 1, and the sensor unit 5 is a sensor case that stores the sensor circuit 52 and is formed following the shapes of the bus bars (positive bus bar 2, negative bus bar 3, intermediate bus bar 4) and is stored in the storage space 14 so as to come into contact with the bus bars (positive bus bar 2, negative bus bar 3, intermediate bus bar 4). and a fitting portion (first clip 53) that is electrically connected to sensor case 51 and sensor circuit 52, and that is arranged in a position on sensor case 51 facing the busbars (positive busbar 2, negative busbar 3, intermediate busbar 4) when sensor case 51 is accommodated in accommodation space 14, and that can fit onto the busbars (positive busbar 2, negative busbar 3, intermediate busbar 4). By fitting the fitting portion (first clip 53) onto the busbars (positive busbar 2, negative busbar 3, intermediate busbar 4), sensor case 51 is fixed to the busbars (positive busbar 2, negative busbar 3, intermediate busbar 4) and sensor circuit 52 is electrically connected to the busbars (positive busbar 2, negative busbar 3, intermediate busbar 4) via the fitting portion (first clip 53).

[0095] With the above configuration, the sensor case 51 and the mating portion (first clip 53), which serves as a terminal electrically connecting to the sensor circuit 52, are integrated into one unit. The mating portion (first clip 53) is directly connected to the busbars (positive busbar 2, negative busbar 3, and intermediate busbar 4). This allows the battery module to be constructed without enlarging the external dimensions of the battery module and while simultaneously reducing the amount of wiring and labor required. Furthermore, by utilizing the storage space 14 inevitably generated by the structure of the busbars (positive busbar 2, negative busbar 3, and intermediate busbar 4), the sensor unit 5 can be mounted without increasing the thickness of the battery module. Furthermore, since the wiring length can be minimized or eliminated, measures to prevent short circuits during assembly can be easily implemented. The same effect can also be achieved during disassembly in secondary reuse or recycling processes. This results in overall cost reduction throughout the entire product life cycle, from battery manufacturing to disposal.

[0096] The battery cells 11 are designed to be subjected to a certain surface pressure. This is due to the structure reducing inter-electrode resistance and limiting volume expansion due to deterioration. For this reason, the space (gap) in the stacking direction of the battery cells 11 is kept to a necessary minimum.

[0097] To meet this demand, the sensor circuit 52 mounted on the exterior surface of the battery cell 11 must be small and thin, which limits the freedom of choice of parts and manufacturing methods, resulting in higher manufacturing costs.

[0098] On the other hand, the mounting area for the busbars (positive busbar 2, negative busbar 3, intermediate busbar 4) will have a space at least equal to the thickness of the stacked cell 1, and as long as they can be accommodated in that space, there is more freedom in the design and selection of parts to be used, which makes it possible to reduce costs.

[0099] Furthermore, EIS (Electrochemical Impedance Spectroscopy) measurements (internal resistance measurements) as a means of determining the internal state of the battery cell 11 require a precise four-terminal connection that corresponds to the measurement range (low internal resistance of the battery cell 11), and for this reason, in the past (see Patent Document 1), individual wiring was performed on the cell tab of the battery cell 11.

[0100] The bus bars (positive bus bar 2, negative bus bar 3, intermediate bus bar 4) are also designed to connect the battery cells 11 over the shortest distance possible to reduce power loss. Therefore, in this embodiment, a connector (first clip 53) having contacts near the connection points between the bus bars (positive bus bar 2, negative bus bar 3, intermediate bus bar 4) and the cell tabs is integrally attached to the sensor case 51 (sensor circuit 52), thereby achieving precision measurement similar to that achieved when the sensor circuit 52 signals are individually wired to the cell tabs. This allows the sensor circuit 52 to be fixed and wired in a single process while maintaining measurement accuracy, and also eliminates the need for adhesives or pressure-sensitive adhesives to fix the sensor circuit 52 wires, which is effective for reducing costs, protecting the environment, and saving resources.

[0101] Note that no current flows through the sensor circuit 52 until the sensor case 51 is attached to the bus bars (positive bus bar 2, negative bus bar 3, and intermediate bus bar 4). Furthermore, removing the sensor case 51 cuts off current to the sensor circuit 52. This prevents short circuits between the positive and negative electrodes of the battery cells 11 (external short circuits of the battery cells 11) via the sensor circuit 52 when the sensor case 51 is attached or detached.

[0102] Since the sensor circuit 52 can function continuously from the time it is newly manufactured until the end of the cell life, charge / discharge control (deterioration suppression) based on the history of the battery cell 11 becomes possible, and as a result, it becomes possible to reduce the overall cost by fully utilizing the capacity of the battery cell 11.

[0103] In this embodiment, the sensor circuit 52 includes a split sensor circuit (sensor circuit 52) ​​divided into multiple parts, the sensor case 51 includes a plurality of split sensor cases (sensor cases 51) that each house one of the split sensor circuits 52, and the split sensor cases (sensor cases 51) are arranged in the housing space 14.

[0104] With the above configuration, even if the accommodation space 14 is divided into many parts by the bus bars (positive bus bar 2, negative bus bar 3, intermediate bus bar 4), the sensor unit 5 (sensor circuit 52) ​​is divided into multiple parts, and the same number of split sensor cases (sensor cases 51) as the sensor units 5 are prepared, and a split sensor circuit (sensor circuit 52) ​​is housed in each split sensor case (sensor case 51) and arranged in the accommodation space 14. As a result, even if there are multiple split sensor cases (sensor cases 51), which have small dimensions, are arranged in the accommodation space 14, and they can be arranged so as not to interfere with the bus bars, thereby increasing the degree of freedom in designing the battery module.

[0105] In this embodiment, the busbars (positive busbar 2, negative busbar 3, intermediate busbar 4) include a positive busbar 2, a negative busbar 3, and an intermediate busbar 4, the battery cells 11 include a first battery cell (battery cell 11(S1), battery cell 11(S2)) that electrically connects between the positive busbar 2 and the intermediate busbar 4, and a second battery cell (battery cell 11(S3), battery cell 11(S4)) that electrically connects between the intermediate busbar 4 and the negative busbar 3, the sensor case 51 is formed following the shape of the intermediate busbar 4, and the fitting portion (first clip 53) is provided at a connection position between the intermediate busbar 4 and the first battery cell (battery cell 11(S1), battery cell 11(S2)) and a connection position between the intermediate busbar 4 and the second battery cell ( Battery cell 11 (S3), battery cell 11 (S4) ) and a plurality of them are arranged so as to face each other at the connection positions.

[0106] With the above configuration, the battery module can be easily constructed by placing the sensor case 51 in the space partitioned by the intermediate bus bar 4 and the inner wall of the storage space 14, which has a large excess space due to the battery module structure. Here, the intermediate bus bar 4 gathers the contact points (N1, N2, P3, P4) with the first battery cell (battery cell 11(S1) and battery cell 11(S2)) and the second battery cell (battery cell 11(S3) and battery cell 11(S4)). This allows for the shortening of the length of the leaf spring-shaped contact electrodes that serve as the connection means (instead of wiring) between the sensor circuit 52 and the cell tabs. This is advantageous in terms of rigidity during mating and material cost savings. Furthermore, the sensor circuit 52 is supported and fixed at multiple points (four points in this embodiment), which is advantageous in terms of vibration resistance. This provides the strength required to secure the sensor circuit 52 and flexibility in the design of the support points. Furthermore, the underside of the sensor case 51 contacts the thin plate portion 12 or the stopper 141 and may be fixed with, for example, an elastic sheet, double-sided tape, or modified silicone adhesive. This is an effective fixing method for providing resistance to vibrations when mounted in a vehicle.

[0107] In this embodiment, the fitting portion (first clip 53) has a clip shape that simultaneously clamps the sensor case 51 and the bus bars (positive bus bar 2, negative bus bar 3, intermediate bus bar 4).

[0108] The above configuration allows for easy attachment and detachment, and realizes this embodiment at low cost. In addition, since it is easy to manage the electrical connection points, resistance components unrelated to the internal state (internal resistance) of the battery cell 11, such as the bus bars (positive bus bar 2, negative bus bar 3, intermediate bus bar 4), can be excluded from the sensing target, thereby enabling precise detection (monitoring) of the internal state of the battery cell 11.

[0109] In this embodiment, the sensor case 51 is made of an electrically insulating material having magnetic properties.

[0110] With the above-described configuration, the inside of the sensor case 51 is electrostatically shielded from the outside, so that even if the sensor circuit 52 is disposed near the bus bar, electromagnetic induction noise to the sensor circuit 52 can be reduced.

[0111] In this embodiment, the positive bus bar 2 includes a positive external terminal P that is connected to the outside, the negative bus bar 3 includes a negative external terminal N that is connected to the outside, a plurality of first battery cells (battery cells 11 (S1), battery cells 11 (S2)) are connected in parallel between the positive bus bar 2 and the intermediate bus bar 4, a plurality of second battery cells (battery cells 11 (S3), battery cells 11 (S4)) are connected in parallel between the intermediate bus bar 4 and the negative bus bar 3, and the fitting portion (first clip 53) is fitted to the sensor case 51 when the sensor case 51 is accommodated in the accommodation space 14. In the sensor case 51, the contact points are arranged to face the connection position (contact point (N1)) between the intermediate bus bar 4 and the first battery cell (battery cell 11 (S1)) connected to the position electrically closest to the positive external terminal P among the first battery cells (battery cell 11 (S1), battery cell 11 (S2)), and the connection position (contact point (P3)) between the intermediate bus bar 4 and the second battery cell (battery cell 11 (S3)) connected to the position electrically closest to the negative external terminal N among the second battery cells (battery cell 11 (S3), battery cell 11 (S4)).

[0112] With the above configuration, the internal state of the battery cell 11 can be detected in a practically effective manner even if the number of connection points with the battery cell 11 is reduced, so that the state of the battery cell 11 can be detected more easily and inexpensively.

[0113] In this embodiment, the battery cell 11 includes a storage section 111 and tab cells (positive electrode cell tab 113, negative electrode cell tab 114) that extend from the storage section 111 and are connected to the bus bars (positive electrode bus bar 2, negative electrode bus bar 3, intermediate bus bar 4), and the fitting section (first clip 53) fits into the bus bars (positive electrode bus bar 2, negative electrode bus bar 3, intermediate bus bar 4) in a manner that clamps the tab cells (positive electrode cell tab 113, negative electrode cell tab 114) together with the bus bars (positive electrode bus bar 2, negative electrode bus bar 3, intermediate bus bar 4).

[0114] With the above configuration, the fitting portion (first clip 53) does not come into contact with the bus bars (positive bus bar 2, negative bus bar 3, intermediate bus bar 4), so the sensor circuit 52 does not sense the resistance component of the bus bars, and the state of the battery cell 11 can be detected with high accuracy.

[0115] In this embodiment, the sensor case 51 further includes a cover (terminal cover 7) fitted into the stacked cell 1 so as to cover the storage space 14, wiring (fourth wiring 74) arranged on the inner wall of the cover (terminal cover 7), and a power supply unit (sensor power supply unit 6a) including a power supply circuit (sensor power supply circuit 62a) that supplies power to the sensor unit 5. The storage space 14 is formed with a plurality of divided spaces by bus bars (positive bus bar 2, negative bus bar 3, intermediate bus bar 4), and the sensor unit 5 is housed in a first divided space 142 formed by the intermediate bus bar 4 among the divided spaces. A power supply input terminal (first connection terminal 521) electrically connected to the sensor circuit 52 is arranged on the surface facing the sub-cover 7, and the power supply unit (sensor power supply unit 6a) is electrically connected to the input side (positive side) of the power supply circuit (sensor power supply circuit 62a) and the holder 61a, which has a power supply circuit (sensor power supply circuit 62a) attached thereto and is housed in a second division space 143 formed between the positive bus bar 2 and the negative bus bar 3 of the division space, and is arranged at a position facing the positive bus bar 2 of the holder 61a when the holder 61a is housed in the second division space 143, and the positive bus bar a second fitting portion (second clip 63) that can be fitted to the negative bus bar 2; a third fitting portion (third clip 64) that is electrically connected to the input side (negative side) of the power supply circuit (sensor power supply circuit 62a) and is arranged at a position facing the negative bus bar 3 of the holder 61a when the holder 61a is accommodated in the second division space 143 and can be fitted to the negative bus bar 3; and a power output terminal (second connection terminal 622) that is electrically connected to the output side of the power supply circuit (sensor power supply circuit 62a) and is arranged at a position facing the cover (terminal cover 7) of the holder 61a. By fitting the mating portion (second clip 63) to the positive bus bar 2, the holder 61a is fixed to the positive bus bar 2 and the power supply circuit (sensor power supply circuit 62a) is electrically connected to the positive bus bar 2 via the second mating portion (second clip 63). By fitting the third mating portion (third clip 64) to the negative bus bar 3, the holder 61a is fixed to the negative bus bar 3 and the power supply circuit (sensor power supply circuit 62a) is electrically connected to the negative bus bar 3 via the third mating portion (third clip 64). By fitting the cover (terminal cover 7) to the stacked cell 1,The wiring (fourth wiring 74) contacts the power output terminal (second connection terminal 622) and the power input terminal (first connection terminal 521) simultaneously, and the power output terminal (second connection terminal 622) is electrically connected to the power input terminal (first connection terminal 521) via the wiring (fourth wiring 74).

[0116] In this embodiment, the stacked cell 1 further includes a cover (terminal cover 7) fitted into the stacked cell 1 so as to cover the accommodation space 14, a first wiring 72 and a second wiring 73 arranged on the inner wall of the cover (terminal cover 7), a third wiring 131 arranged on the outer wall of the accommodation space 14 that contacts the cover (terminal cover 7), and a power supply unit (sensor power supply unit 6a) including a power supply circuit (sensor power supply circuit 62a) that supplies power to the sensor unit 5, and the accommodation space 14 is formed with a plurality of divided spaces by bus bars (positive bus bar 2, negative bus bar 3, intermediate bus bar 4). The sensor unit 5 is accommodated in a first divided space 142 formed by the intermediate bus bar 4 among the divided spaces, and a power input terminal (first connection terminal 521) electrically connected to the sensor circuit 52 is arranged on the surface of the sensor case 51 facing the cover (terminal cover 7). The power supply unit (sensor power supply unit 6a) has a power supply circuit (sensor power supply circuit 62a) attached thereto and a holder 61a accommodated in a second divided space 143 formed between the positive bus bar 2 and the negative bus bar 3 among the divided spaces, and an input side of the power supply circuit (sensor power supply circuit 62a) a second fitting portion (second clip 63) electrically connected to the input side (positive side) of the power supply circuit (sensor power supply circuit 62a) and arranged at a position facing the positive bus bar 2 of the holder 61a when the holder 61a is accommodated in the second divided space 143, and capable of fitting with the positive bus bar 2; a third fitting portion (third clip 64) electrically connected to the input side (negative side) of the power supply circuit (sensor power supply circuit 62a), and arranged at a position facing the negative bus bar 3 of the holder 61a when the holder 61a is accommodated in the second divided space 143, and capable of fitting with the negative bus bar 3; and a power output terminal (second connection terminal 622) electrically connected to the output side of the circuit (sensor power supply circuit 62a) and arranged in a position facing the cover (terminal cover 7) of the holder 61a, and by fitting the second fitting portion (second clip 63) to the positive bus bar 2, the holder 61a is fixed to the positive bus bar 2 and the power supply circuit (sensor power supply circuit 62a) is electrically connected to the positive bus bar 2 via the second fitting portion (second clip 63), and by fitting the third fitting portion (third clip 64) to the negative bus bar 3,When the holder 61a is fixed to the negative bus bar 3 and the power supply circuit (sensor power supply circuit 62a) is electrically connected to the negative bus bar 3 via the third fitting portion (third clip 64), and the cover (terminal cover 7) is fitted into the stacked cell 1, the first wiring 72 simultaneously contacts the power supply output terminal (second connection terminal 622) and the third wiring 131, and the second wiring 73 simultaneously contacts the power supply input terminal (first connection terminal 521) and the third wiring 131, so that the power supply output terminal (second connection terminal 622) is electrically connected to the power supply input terminal (first connection terminal 521) via the first wiring 72, the second wiring 73, and the third wiring 131.

[0117] With the above configuration, no current is passed through the power supply circuit (sensor power supply circuit 62a) until the power supply unit (sensor power supply unit 6a) is attached to the positive bus bar 2 and the negative bus bar 3. Furthermore, the current to the power supply circuit (sensor power supply circuit 62a) is cut off by removing the power supply unit (sensor power supply unit 6a) from the positive bus bar 2 or the negative bus bar 3. This prevents a short circuit between the positive and negative electrodes of the battery cell 11 via the power supply circuit (sensor power supply circuit 62a) (an external short circuit of the battery cell 11) when the power supply circuit (sensor power supply circuit 62a) is attached or detached.

[0118] Furthermore, with the above configuration, no current flows through the sensor circuit 52 until the cover (terminal cover 7) is attached to the stacked cell 1. Furthermore, removing the cover (terminal cover 7) from the stacked cell 1 cuts off the current to the sensor circuit 52. This prevents a short circuit between the positive and negative electrodes of the battery cell 11 (external short circuit of the battery cell 11) through the cover (terminal cover 7) having wiring (first wiring 72 and second wiring 73, or fourth wiring 74) when the cover (terminal cover 7) is attached or detached.

[0119] In this embodiment, the stacked cell 1 has a pair of fastening portions 112 that fasten multiple battery cells 11 together, and the fastening portions 112 are arranged at both ends of at least one side of the stacked cell 1, and the storage space 14 is arranged between the pair of fastening portions 112.

[0120] With the above configuration, the storage space 14 is disposed in an existing space inside the outer shape of the stacked cell 1, so that the sensor unit 5 and the like disposed in the storage space 14 can be protected.

[0121] Although the embodiments of the present invention have been described above, the above embodiments merely illustrate some of the application examples of the present invention, and the technical scope of the present invention is not intended to be limited to the specific configurations of the above embodiments. Furthermore, the above embodiments can be combined as appropriate.

[0122] This application claims priority based on Japanese Patent Application No. 2022-085496, filed with the Japan Patent Office on May 25, 2022, the entire contents of which are incorporated herein by reference.

Claims

1. a stacked cell in which a plurality of battery cells are stacked; a bus bar connected to the battery cell; a sensor unit electrically connected to the bus bar and including a sensor circuit that measures a state of the battery cell, the bus bar includes a staircase-shaped bus bar having two or more steps, and is arranged in an accommodation space formed on one side surface of the stacked cell; The sensor unit a sensor case that accommodates the sensor circuit and is formed to follow the shape of the bus bar and is accommodated in the accommodation space so as to be in contact with the bus bar; a fitting portion electrically connected to the sensor circuit, disposed in a position on the sensor case facing the bus bar when the sensor case is housed in the housing space, and capable of fitting onto the bus bar; The battery module has a structure in which the sensor case is fixed to the bus bar and the sensor circuit is electrically connected to the bus bar via the fitting portion by fitting the fitting portion to the bus bar.

2. 2. The battery module according to claim 1, wherein the sensor circuit includes a split sensor circuit divided into a plurality of parts, the sensor case includes a plurality of split sensor cases that respectively house the split sensor circuits, and the sensor cases are arranged in the housing space.

3. the bus bars include a positive bus bar, a negative bus bar, and an intermediate bus bar; The battery cell is a first battery cell electrically connecting the positive bus bar and the intermediate bus bar; a second battery cell electrically connecting the intermediate bus bar and the negative bus bar, the sensor case is formed to follow the stepped shape of the intermediate bus bar, The fitting portion is 2. The battery module according to claim 1, wherein a plurality of the sensor cases are arranged so as to face a connection position of the intermediate bus bar with the first battery cell and a connection position of the intermediate bus bar with the second battery cell when the sensor case is accommodated in the accommodation space.

4. The battery module according to claim 1 , wherein the fitting portion has a clip shape that simultaneously holds the sensor case and the bus bar.

5. 2. The battery module according to claim 1, wherein the sensor case is made of an electrically insulating material having magnetic properties.

6. the positive bus bar includes a positive external terminal for connection to the outside, the negative bus bar includes a negative external terminal that is connected to the outside, a plurality of the first battery cells are connected in parallel between the positive bus bar and the intermediate bus bar; a plurality of the second battery cells are connected in parallel between the intermediate bus bar and the negative bus bar; The fitting portion is 4. The battery module according to claim 3, wherein, when the sensor case is accommodated in the accommodation space, the intermediate bus bar is arranged to face a connection position between the first battery cell connected to a position electrically closest to the positive external terminal among the first battery cells in the sensor case and the intermediate bus bar, and a connection position between the second battery cell connected to a position electrically closest to the negative external terminal among the second battery cells in the sensor case and the intermediate bus bar.

7. the battery cell includes a power storage unit and a tab cell extending from the power storage unit and connected to the bus bar; The battery module according to claim 1 , wherein the fitting portion is fitted to the bus bar in a manner that the tab cell is sandwiched between the fitting portion and the bus bar.

8. a cover fitted to the stacked cell so as to cover the storage space; a first wiring and a second wiring disposed on an inner wall of the cover; a third wiring disposed on an outer wall of the accommodation space in contact with the cover; a power supply unit including a power supply circuit that supplies power to the sensor unit, a plurality of divided spaces are formed in the accommodation space by the bus bars; the sensor unit is accommodated in a first division space formed by the intermediate bus bar among the division spaces, a power supply input terminal electrically connected to the sensor circuit is disposed on a surface of the sensor case facing the cover; The power supply unit a holder to which the power supply circuit is attached and which is accommodated in a second divided space formed between the positive bus bar and the negative bus bar in the divided space; a second fitting portion electrically connected to an input side of the power supply circuit, disposed at a position facing the positive bus bar of the holder when the holder is housed in the second division space, and capable of fitting with the positive bus bar; a third fitting portion electrically connected to an input side of the power supply circuit, disposed at a position facing the negative bus bar of the holder when the holder is housed in the second division space, and capable of fitting with the negative bus bar; a power output terminal electrically connected to an output side of the power supply circuit and disposed at a position facing the cover of the holder, By fitting the second fitting portion to the positive bus bar, the holder is fixed to the positive bus bar and the power supply circuit is electrically connected to the positive bus bar via the second fitting portion, by fitting the third fitting portion to the negative bus bar, the holder is fixed to the negative bus bar and the power supply circuit is electrically connected to the negative bus bar via the third fitting portion; 4. The battery module according to claim 3, wherein by fitting the cover into the stacked cell, the first wiring contacts the power output terminal and the third wiring simultaneously, and the second wiring contacts the power input terminal and the third wiring simultaneously, so that the power output terminal is electrically connected to the power input terminal via the first wiring, the second wiring, and the third wiring.

9. the stacked cell has a pair of fastening portions that fasten the plurality of battery cells together, and the fastening portions are arranged on both ends of at least one side surface of the stacked cell; The battery module according to claim 1 , wherein the accommodation space is disposed between the pair of fastening portions.

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