battery pack

Abstract

The present invention provides a battery pack which does not require a bus bar case.　The present invention provides a battery pack which is obtained by stacking a plurality of battery cells in a first direction, and which is characterized in that: a first spacer or a second spacer is disposed between the plurality of battery cells; the first spacer has a first side that extends in a second direction; the first side is provided with a first U-shaped part that extends in the first direction; the first spacer is provided with a first partition wall on the outer side of the first U-shaped part in the second direction; the second spacer has a second side that extends in the second direction; the second side is provided with a second U-shaped part that extends in the first direction and has a U-shaped cross-section; a bus bar housing part is formed between the first partition wall that is formed on the first spacer and another first partition wall that is formed on another first spacer which is adjacent to the first spacer in the first direction; and the first U-shaped part and the second U-shaped part are continuously formed in the first direction, thereby forming a wiring housing part that extends in the first direction.

Description

[Technical Field]

[0001] The present invention relates to a configuration of a busbar housing and a wiring housing in which a voltage detection line is arranged in an assembled battery formed by stacking a plurality of battery cells. [Background technology]

[0002] Conventional battery packs use busbar cases as dedicated components for accommodating busbar accommodating sections and voltage detection wires. Patent Document 1 describes a configuration in which a busbar case that corresponds to the outer shape of a cell stack is placed on top of a cell stack in which batteries are stacked. Patent Document 2 describes a configuration in which a flexible wiring board is used as a voltage detection wire instead of a harness. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2018-26203 [Patent Document 2] Patent Publication No. 2015-22965 Summary of the Invention [Problem to be solved by the invention]

[0004] A new busbar case must be designed for each new battery pack structure, which has a significant impact on costs. [Means for solving the problem]

[0005] The present invention is intended to solve the above-mentioned problems, and has the following main features.

[0006] (1) A battery pack in which a plurality of rectangular batteries are stacked in a first direction, A first spacer having a rectangular outer shape or a second spacer having a rectangular outer shape is disposed between the plurality of batteries; the first spacer has a first side extending in a second direction perpendicular to the first direction, and a first U-shaped portion having a U-shaped cross section extending in the first direction is formed on the first side, and a first partition wall extending in the second direction is formed outside the first wiring accommodating portion in the second direction; and the second spacer has a second U-shaped portion extending in the second direction. a bus bar accommodating portion is formed between the first partition wall formed on the first spacer and another first partition wall formed on another first spacer adjacent to the first spacer in the first direction, and the first U-shaped portion and the second U-shaped portion are formed continuously in the first direction to form a wire accommodating portion extending in the first direction.

[0007] (2) The battery pack according to (1), wherein the bus bar accommodating portion is defined in the second direction by the first U-shaped portion and the second U-shaped portion.

[0008] (3) The battery pack described in (1), wherein the first spacer has a first rib at an end in the second direction, and the second spacer has a second rib at an end in the second direction; and the bus bar accommodating portion has an end in the second direction defined by the first rib and the second rib. [Effects of the Invention]

[0009] The present invention ensures the arrangement of wiring such as voltage detection lines without using a busbar case separate from the spacer. Alternatively, it is possible to form busbar accommodating sections for accommodating the connection configuration of each busbar without using a busbar case separate from the spacer. This reduces the cost of the battery module. Furthermore, compared to using a busbar case separate from the spacer, it is possible to suppress stress caused by the difference in thermal expansion between the busbar case and the stacked battery configuration, thereby improving the reliability of the battery module. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. [Figure 2] FIG. 10 is a perspective view of the appearance of a battery pack according to a comparative example. [Figure 3] FIG. 10 is an exploded perspective view of a battery pack according to a comparative example. [Figure 4] FIG. 10 is a plan view of a bus bar case in a comparative example. [Figure 5] FIG. 10 is a plan view showing a state in which bus bars and wiring are housed in a bus bar case in a comparative example. [Figure 6] FIG. 2 is a perspective view of a battery pack including a signal processing circuit protection case. [Figure 7] 2 is a perspective view showing a bus bar accommodating portion and a wire accommodating portion according to the first embodiment. FIG. [Figure 8] 3 is an enlarged perspective view showing a bus bar accommodating portion and a wire accommodating portion in the first embodiment. FIG. [Figure 9] FIG. 1 is a perspective view of a battery pack according to a first embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] The present invention will be described in detail below with reference to examples. The present invention is characterized by a configuration that allows the busbar case to be omitted. First, a configuration in which a busbar case is used will be described as a comparative example. Even in the comparative example, the components other than the busbars can be applied as the configuration of the present invention.

[0012] FIG. 1 is a perspective view of a battery cell 1. As shown in FIG. 1, the battery cell 1 has a battery can 2, a battery lid 3, a positive electrode terminal 4, a negative electrode terminal 5, a gas release valve 6, a liquid inlet tap 7, an electrolyte, charging / discharging elements, and an insulating case (not shown). The battery cell 1 uses a rechargeable secondary battery such as a lithium-ion secondary battery. The battery cell 1 of the first embodiment corresponds to a single cell of a battery pack according to one embodiment of the present invention.

[0013] The battery can 2 has a rectangular parallelepiped shape with one end open, and is made of aluminum or an aluminum alloy. The battery can 2 has a pair of opposing side plates 2a with a large area, a pair of opposing side plates 2b with a small area, and a bottom plate 2c on the opposite side of the opening. The internal space of the battery can 2 contains charging / discharging elements covered with an insulating case, and an electrolyte is poured into it. The positive electrode of the charging / discharging elements is connected to a positive terminal 4, and the negative electrode of the charging / discharging elements is connected to a negative terminal 5.

[0014] The battery lid 3 has the same rectangular flat plate shape as the bottom plate 2c, is made of aluminum or an aluminum alloy, and closes the opening of the battery can 2. The battery lid 3 is joined to the opening of the battery can 2 by joining means such as laser welding. A liquid filling hole (not shown) is formed through the battery lid 3, and the electrolyte is poured through the liquid filling hole, which is closed by a liquid filling stopper 7.

[0015] A gas release valve 6 is provided in the center of the battery lid 3. When the battery cell 1 generates heat due to an abnormality such as overcharging, generating gas, and the pressure inside the battery can 2 increases and reaches a predetermined pressure, the gas release valve 6 ruptures and releases the gas from inside the container, thereby reducing the pressure inside the battery can 2.

[0016] Furthermore, through-holes (not shown) are formed at one end and the other end of the battery lid 3, and a positive terminal 4 and a negative terminal 5 are attached to the through-holes. The portions of the positive terminal 4 and the negative terminal 5 that are exposed to the outside from the battery lid 3 are each formed as a rectangular parallelepiped and have a flat top surface. Electricity generated in the battery cell 1 is supplied to an external device via the positive terminal 4 and the negative terminal 5, or externally generated power is supplied to a charging / discharging element via the positive terminal 4 and the negative terminal 5 for charging.

[0017] Fig. 2 is a perspective view showing the appearance of a battery pack in a comparative example. The battery pack 10 is installed in, for example, a hybrid vehicle driven by an internal combustion engine and a motor, or an electric vehicle driven by a motor, and is used as a driving source for the motor. As shown in Fig. 2, the battery pack 10 has a block 11 and a busbar case assembly 12.

[0018] Figure 3 is an exploded perspective view of a battery pack in a comparative example. As shown in Figure 3, a block 11 has a plurality of stacked battery cells 1 and spacers 20, a pair of end plates 26, 27, and a pair of side rails 24, 25. The block 11 has a laminated structure in which the stacked battery cells 1, spacers 21, and other components are integrated.

[0019] The spacers 20 are made of insulating synthetic resin and, as shown in Fig. 3, are sandwiched alternately between adjacent battery cells 1 and stacked together with the battery cells 1 in the x direction (also referred to as the first direction). Each spacer 20 has recesses on both sides that correspond to the shape of the battery cells 1, and the recesses hold the battery cells 1 in place and regulate their movement in the y direction (also referred to as the second direction) and z direction (also referred to as the third direction).

[0020] The end plates 26 are formed from plate-shaped members made of die-cast aluminum. Although not shown in Figure 3, spacers 21 are present between the end plates 26 and the battery cells 1 and are arranged in the stacking direction of the battery cells 1. The end plates 26 have fixing parts with fixing bolt holes formed therein for fixing the side rails 24 and 25.

[0021] Fixing bolt holes and gas exhaust duct fixing holes are formed in the end plate 26. The fixing bolt holes correspond to fixing parts that fix the battery pack, and the gas exhaust duct fixing holes correspond to gas exhaust ducts that exhaust gas released from inside the cells to the outside of the battery pack.

[0022] The end plate 27 is formed in the same manner as the end plate 26. That is, although not shown in FIG. 3 , a spacer 21 is present between the end plate 27 and the battery cells 1 and is arranged in the stacking direction of the battery cells 1. The end plate 27 also has a fixing bolt hole for fixing the battery pack 10, a negative electrode connection terminal, and a fixing hole for a gas exhaust duct. The bent portions 24b, 25b of the end plate 26, end plate 27, side rail 24, and side rail 25 are configured to be fastened together with bolts 28.

[0023] The side rails 24 hold the end plates 26, the multiple battery cells 1, the multiple spacers 21, and the end plates 27 in a state where they are pressed together in the stacking direction. The side rails 24 have connecting portions 24c and bent portions 24b, and are fixed to the end plates 26, 27 by bolts 28 inserted through fixing holes 24a in the bent portions 24b.

[0024] The side rail 25 has a similar structure as the side rail 24, being a mirror image of the side rail 24. The side rail 25 is made of the same metal material as the side rail 24 and has the same function as the side rail 24. The side rail 25 is arranged opposite the side rail 24 in the y direction, with the stacked battery cells 1 sandwiched between them, and has a rail main body 25c extending in the x direction and bent portions 25b bent at both ends of the rail main body 25c in the x direction so that they face each other. The bent portions 25b have fixing holes 25a through which bolts 28 are inserted.

[0025] 3, the busbar case assembly 12 includes a busbar 31, two busbar cases 35, a gas exhaust duct 234, two covers 34, and the busbar case 35. Although omitted in FIG. 3, the busbar case assembly 12 also includes a harness including a voltage detection line and a flexible wiring board.

[0026] 3, as also shown in Fig. 4, the bus bar 31 has an inter-cell bus bar 31a, a negative electrode bus bar 31b, and a positive electrode bus bar 31c, and each component is housed in a frame formed in a bus bar case 35. The inter-cell bus bar 31a is configured to electrically connect the positive electrode terminal 4 of one battery cell 1 to the negative electrode terminal 5 of another adjacent battery cell 1. The negative electrode bus bar 31b and the positive electrode bus bar 31c are connected to external terminals.

[0027] 3 and 4, the busbar case 35 has a detection circuit housing portion 36 for housing a detection circuit group. The detection circuit group may be, for example, a wire harness (hereinafter referred to as a "harness") including a group of wires for measuring the voltage and temperature of the battery, or a flexible wiring board for the same purpose. In this specification, the term "detection circuit group" may also include a terminal portion, an electric wire portion, a sensor portion, and a connector portion. The sensor portion is in contact with the battery lid 3, measures the temperature of the battery lid 3, and outputs the measurement result.

[0028] The gas exhaust duct 234 has a gas exhaust port 233 and collects gas exhausted from the gas exhaust valve 6 in isolation in the center in the y direction and discharges it from the gas exhaust port 233. The gas exhaust duct 234 is fixed to the female threads of the first end plate 26 and the second end plate 27 with screws located at both ends in the x direction. The two covers 34 have the function of insulating and protecting the components of the bus bar case assembly 12 and are arranged to cover the bus bar 31 and detection circuits. Each cover 34 is fitted and fixed to the bus bar case 35. The bus bar case 35 has a frame for forming multiple bus bar housing sections 37 aligned in the stacking direction of the battery cells 1, and is configured to house the inter-cell bus bar 31a, negative electrode bus bar 31b, and positive electrode bus bar 31c within the frame.

[0029] Fig. 4 is a plan view of the busbar case 35 as viewed from above. In Fig. 4, a gas exhaust duct 234 extends in the x direction at the center in the y direction, and busbar cases 35 are arranged on either side of the gas exhaust duct 234 in the y direction. In each busbar case 35, busbar accommodating sections 37 that respectively store an inter-cell busbar 31a, a negative electrode busbar 31b, and a positive electrode busbar 31c are arranged in the x direction.

[0030] Each busbar case 35 is formed with a detection circuit housing 36 for housing a detection circuit group. The detection circuit group may be a harness or a flexible circuit board. The detection circuit may be disposed above the gas exhaust duct 234, for example.

[0031] 5 is a plan view showing a case where a flexible wiring board 40 is used for the detection circuits. In FIG. 5, the bus bar case 35 and the gas exhaust duct 234 are as described in FIG. 4. The flexible wiring board 40 is disposed in the detection circuit housing 36. Each of the multiple wires 41 formed on the flexible wiring board 40 is connected to the bus bars 31a, 31b, and 31c, and sends a detected voltage to a signal processing circuit 45. In addition, a signal from a thermistor or the like in contact with the battery is sent to the signal processing circuit 45 for temperature detection.

[0032] 5, signal processing circuit 45 is disposed above gas exhaust duct 234. Signal processing circuit 45 processes signals such as the battery voltage and thermistor signals to perform the necessary control. If the circuit scale is large, the signal processing required to perform the necessary control may involve sending the signal wirelessly to an external device, creating a control signal using an external signal processing circuit, and then receiving this signal wirelessly again.

[0033] 5, signal processing circuit 45 is disposed above gas exhaust duct 234. Therefore, in order to protect signal processing circuit 45, a circuit board protective cover 47 is used as shown in FIG. 6. As a specific configuration, for example, a notch is formed in part of cover 34, and part of flexible wiring board 40 is pulled out from this notch and disposed above exhaust duct 234. The flexible wiring board 40 exposed to the outside is protected by circuit board protective cover 47. Circuit board protective cover 47 is made of an insulating material such as resin.

[0034] 5, wiring 41 for receiving signals and signal processing circuit 45 are formed on the same flexible wiring board 40. Flexible wiring board 40 on which wiring 41 is formed is located at the bottom of detection circuit housing portion 36, and signal processing circuit 45 is disposed above gas exhaust duct 234, so a step is formed. However, flexible wiring board 40, whose base material is formed of a resin such as polyimide, can flexibly overcome this step. Note that each wiring 41 formed on flexible wiring board 40 branches out and connects to each bus bar 31, and if each wiring 41 branches out together with the resin such as polyimide that is the base material, the mechanical strength will be greater.

[0035] 5, signal processing circuit 45 is arranged above gas exhaust duct 234, but it is also possible to arrange the signal processing circuit in each detection circuit housing section depending on the layout of flexible wiring board 40. In this case, since space does not allow for a large circuit scale, data is often sent to an externally arranged signal processing circuit to create a control signal.

[0036] The above configuration is for the case where the detection circuits are configured with a flexible wiring board 40, but the same applies when the detection circuits are formed with a harness. When the detection circuits are configured with a harness, the detection circuits are bulkier than when they are configured with a flexible wiring board, but basically the same configuration can be used. The configuration of the detection circuits described above can also be applied to the configuration of the embodiment of the present invention described in Example 1, which does not have a bus bar case.

[0037] In the examples shown in Figures 3 to 5, two busbar cases are used. The dimensions of the busbar case 35 are the same as those of the block 11, which is the stack of batteries, at least in the x direction, and because the external shape is large, development takes time. Although a single busbar case may be used, it is essentially the same. The manufacturing cost of the busbar case 35 is also high. Furthermore, if the thermal expansion coefficients of the busbar case 35 and the block 11, which is the stack of batteries, differ, stress may be generated in the components whenever the temperature of the battery pack rises. To address this issue, the configuration described in the following example allows the busbar to be housed without using an independent busbar case 35 separate from the spacer. [Example]

[0038] Fig. 7 is an exploded perspective view of a block 11, which is a stack of batteries according to Example 1. A feature of Example 1 is that the busbar case can be omitted. In Example 1, as shown in Fig. 7, a detection circuit accommodating portion 36 and a busbar accommodating portion 37 are formed by the shapes of a plurality of spacers 21, 22 within the block.

[0039] In Figure 7, multiple battery cells 1 are stacked in the x direction via first spacers 21 or second spacers 22. The spacers 21 and 22 alternately partition the battery cells 1 in the x direction. The spacers 21 and 22 have the same configuration except for the position of the partition wall 60 that forms the busbar housing section 37. Each spacer 21, 22 has a side cover 80, and the battery cells 1 are housed in the space formed by the side covers 80 butting against each other.

[0040] Spacers 21 and 22 have the same configuration except for the position of the partition wall 60, so the following description will mainly focus on spacer 21. Two wire housings 50 with a U-shaped cross section are formed at the upper ends of spacers 21 and 22. The U-shaped portions extend in the +y direction of the spacer. The multiple U-shaped portions are arranged with spaces between them. The wire housings 50 are formed in positions that are symmetrical with respect to the center line of the spacer in the y direction. Because the wire housings 50 are formed in the same position on both spacers 21 and 22, stacking spacers 21, 22, and battery cells 1 in the x direction forms a detection circuit housing 36 resembling a U-shaped groove extending in the x direction.

[0041] In Figure 7, spacers 21 and spacers 22 are stacked in succession in the x direction, sandwiching a battery cell 1 between them. A rib 70 is formed near the end of the spacer in the +y direction. The ribs 70 are stacked so that they butt against each other in the x direction, forming a nearly continuous bank. The end of the spacer in the +y direction is defined by the ribs 70 of adjacent spacers.

[0042] Near the +y-direction end, a partition wall 60 is formed between the rib 70 and the wire accommodating portion 50 having a U-shaped cross section (hereinafter also referred to as "U-shaped portion 50"). The partition wall 60 forms part of the spacer 21. Meanwhile, in this portion, the partition wall 60 is not formed on the spacer 22 adjacent to the spacer 21 in the +x direction. The partition wall 60 is formed on the spacer 21 adjacent to the spacer 22 in the +x direction. Therefore, at the +y-direction end, a space surrounded by the U-shaped portion 50, the partition wall 60, and the rib 70 is formed. In the first embodiment, this space is used as the bus bar accommodating portion 37. In FIG. 7 , at the +y-direction end of the spacers 21 and 22, the bus bar accommodating portions 37 are arranged continuously in the x direction while being partitioned by the partition wall 60.

[0043] 7, near the end in the -y direction, a partition wall 60 is formed on the spacer 22, and no partition wall 60 is formed on the spacer 21. Therefore, near the end in the -y direction, a bus bar accommodating portion 37 is formed between the partition wall 60 formed on the spacer 22 and the partition wall 60 formed on the other spacer 22. Note that, near the end in the -y direction, the bus bar accommodating portion 37 is also formed by the U-shaped portion 50, the partition wall 60, and the rib 70, just like on the +y side.

[0044] In Fig. 7, if the pitch of the bus bar accommodating sections 37 in the x direction is px, the bus bar accommodating sections 37 formed in the +y direction are offset by px / 2 in the x direction from the bus bar accommodating sections 37 formed in the -y direction. In Fig. 7, the positive electrode terminal 4 of one battery cell 1 and the negative electrode terminal 5 of another battery cell 1 are accommodated in the bus bar accommodating section 37. As shown in Fig. 7, the positive electrode terminal 4 and the negative electrode terminal 5 are connected by the bus bar 31a within the bus bar accommodating section 37.

[0045] As described in Fig. 7, near the end in the +y direction, the bus bar accommodating sections 37 separated by the partition walls 60 are formed continuously in the x direction, and near the end in the -y direction, the bus bar accommodating sections 37 separated by the partition walls 60 are also formed continuously in the x direction. That is, a configuration similar to the bus bar accommodating sections 37 formed in the two bus bar cases shown in Fig. 3 is also formed in Fig. 7. In addition, the detection circuit accommodating sections formed in the two bus bar cases 35 shown in Fig. 3 are also realized by two rows of U-shaped sections.

[0046] 7, the same structure can be formed simply by changing the shape of the upper parts of the spacers 21 and 22, without using the busbar case 35. This reduces the manufacturing costs of the busbar case 35 and shortens the development time for the busbar case 35. Furthermore, it eliminates stress during operation and non-operation of the battery due to the difference in thermal expansion coefficient between the blocks 11 that make up the stacked structure of the battery cells 1 and the busbar case 35, thereby improving reliability.

[0047] In FIG. 7, the spacers 21 and 22 have a somewhat complicated shape at their upper portions in the z direction, including a U-shaped portion 50, a partition wall 60, and ribs 70. However, the spacers 21 and 22 are made of resin and shaped by molding. The spacers 21 and 22 can be provided as an integrated resin part. In other words, once the mold is designed and manufactured, they can be reused. Therefore, manufacturing costs are not increased.

[0048] Furthermore, spacer 21 and spacer 22 have different shapes, but the only difference is the partition wall 60. In Fig. 7, spacer 21 has partition wall 60 formed near the +y-direction end, but does not have partition wall 60 formed near the -y-direction end. On the other hand, spacer 22 does not have partition wall 60 formed near the +y-direction end, but does have partition wall 60 formed near the -y-direction end.

[0049] In other words, spacer 21 and spacer 22 are in a line-symmetric relationship with respect to the z-axis that includes the center in the y-direction. Therefore, spacer 21 and spacer 22 can be formed using the same mold, and when in use, spacer 21 and spacer 22 can be used in a state where they are flipped left and right. In other words, even if spacers 21 and 22 exist, they can be shaped using a single mold, so there is no increase in manufacturing costs.

[0050] 7 also shows a perspective view illustrating the state in which the bus bar 31a is installed in the bus bar accommodating section 37 and the state in which the flexible wiring board 40 is placed in the detection circuit accommodating section 36. The bus bar 31a is made by bonding a phosphor bronze plate and an aluminum or aluminum alloy plate together by, for example, butt welding. It is made of aluminum, which forms the positive electrode terminal 4 of the battery cell 1, and copper, which forms the negative electrode terminal. The bus bar 31a is attached to the positive electrode terminal 4 and negative electrode terminal 5 of the battery cell 1 by laser welding, crimping, or the like. In addition, a voltage detection terminal is formed on the bus bar 31a, and is connected to wiring branching from the flexible wiring board 40 placed in the detection circuit accommodating section 36.

[0051] 7 shows the flexible wiring board 40 placed in the detection circuit housing 36 formed by the U-shaped portion 50. The flexible wiring board 40 has a large number of wires 41 extending in the x direction, and each wire 41 branches out and connects to a voltage detection terminal formed on the bus bar 30a. The wires 41 formed on the flexible wiring board 40 also include wires for connecting to thermistors attached to the battery cells 1.

[0052] The general shape of the flexible wiring board 40 is generally the same as that of the flexible wiring board 40 in Fig. 5. However, whereas in Fig. 5 the flexible wiring board 40 is disposed in the detection circuit accommodating section 36 formed in the busbar case 35, in Fig. 7 the busbar case 35 does not exist and the flexible wiring board 40 is disposed in the detection circuit accommodating section 36 formed by the spacer 21 and the U-shaped section 50 formed in the spacer 22.

[0053] 7, as shown in FIGS. 3 to 6, a gas exhaust duct 234 is arranged to cover the gas exhaust valve 6 of the battery cell 1. Furthermore, the cover 34 shown in FIGS. 3 to 6 directly covers the detection circuit housing portion 36 and bus bar housing portion 37 formed by the U-shaped portion 50. The signal processing circuit in the detection circuit group is arranged above the gas exhaust duct, as shown in FIG. 5.

[0054] 5 and 6, a cutout is formed in part of cover 34, and the portion of flexible wiring board 40 including signal processing circuit 45 is placed above gas exhaust duct 234. Then, signal processing circuit 45 is covered with protective cover 47. Therefore, the external appearance of the battery module in the configuration in FIG. 7 is the same as that in FIG. 6.

[0055] 7, a flexible wiring board 40 is used as the detection circuit group. However, the same applies when a harness disposed in the detection circuit housing 36 formed by the U-shaped portion 50 is used instead of the flexible wiring board 40. That is, a harness is disposed in the detection circuit housing 36 formed by the U-shaped portion 50 instead of the flexible wiring board 40. Then, each wire of the harness is connected to a voltage detection terminal formed on the bus bar 31a. Meanwhile, the signal processing circuit 45 is similarly disposed above the gas exhaust duct 234. In the case of a harness, the signal processing circuit 45 is separately formed above the gas exhaust duct 234. The signal processing circuit 45 is then covered by a protective cover 47. Although the wiring volume of the harness is larger than that in the case of a flexible wiring board, the basic appearance of the battery module is the same as that shown in FIG. 6.

[0056] Figure 8 is an enlarged perspective view of a block 11, which is a stack of battery cells 1 in Example 1. The basic configuration of block 11 is the same as that described in Figure 7. That is, a U-shaped portion 50 is formed at the upper ends of spacers 21 and 22, a detection circuit accommodating portion 16 is formed, and a bus bar accommodating portion 37 is formed in the area surrounded by U-shaped portion 50, partition wall 60, and rib 70. This configuration makes it possible to protect bus bar 31a and the voltage detection terminal attached to bus bar 31a.

[0057] 8, the height h1 of the partition wall 60 is the difference between the height in the z direction of the spacer in the portion where there is no partition wall 60 and the height in the z direction of the spacer in the portion where there is partition wall 60. It can also be said that the height h1 of the partition wall 60 is the same as the height h1 of the U-shaped portion 50.

[0058] 8, the U-shaped portion 50 is positioned higher in the z direction than the position where the bus bar 31a is attached. This facilitates connection between the wiring branching from the flexible wiring board 40, which is placed inside the detection circuit housing portion 36 formed by the U-shaped portion 50, and the voltage detection terminal attached to the bus bar 31a. The same applies when the detection circuits are formed by a harness instead of the flexible wiring board 40.

[0059] In FIG. 8 , the positive terminal 4 of one battery and the negative terminal 5 of another battery are present in the bus bar accommodating section 37 separated by the partition wall 60, and the positive terminal 4 and the negative terminal 5 are connected by the bus bar 31. The positive terminal 4 and the negative terminal 5 are separated by a spacer 22. However, due to requirements for mounting the bus bar 31a, a partition wall 61 having a height lower than the partition wall 60 may be disposed. However, even in this case, it is desirable that the partition wall 61 be lower in height than the bus bar 31a.

[0060] FIG. 9 is a perspective view showing multiple battery cells 1 stacked in the x direction with spacers 21 or 22 interposed between them. The stacked battery cells 1 are sandwiched between end plates 90. A gas release valve 6 is located in the center of each battery cell 1 in the y direction. Therefore, the gas release valves 6 are arranged at a constant pitch in the x direction. A gas release duct 234, shown in FIG. 3 and other figures, is arranged to cover the row of gas release valves.

[0061] In Fig. 9, on both sides of the row of gas release valves in the y direction, detection circuit accommodating sections 36 are formed by U-shaped sections 50 formed in spacers 21 and 22. Detection circuit accommodating sections 36 extend in the x direction. In Fig. 9, bus bar accommodating sections 37 are formed further outside of detection circuit accommodating sections 36. Bus bar accommodating section 37 is partitioned on the +y direction side by a partition wall 60 formed in spacer 21, and on the -y direction side by a partition wall 60 formed in spacer 22.

[0062] If the pitch of the bus bar accommodating sections 37 in the x direction is px, the position of the bus bar accommodating section 37 on the +y side and the position of the bus bar accommodating section 37 on the -y side are offset by px / 2 in the x direction. Each bus bar accommodating section 37 accommodates the positive terminal 4 of a battery cell 1 and the negative terminal 5 of the adjacent battery. The positive terminal 4 and negative terminal 5 are connected by the bus bar 31a by laser welding, crimping, or the like.

[0063] 9, the detection circuit wiring 40 shown in FIG. 7 is arranged in the detection circuit housing 36. The detection circuit wiring may be a flexible wiring board 40 or a harness. In either case, each wire 41 of the detection circuit wiring 40 is connected to a voltage detection terminal formed on the bus bar 31a arranged in the bus bar housing 37. Then, the cover 34 shown in FIG. 3 is arranged to cover the detection circuit housing 36 extending in the x direction and the bus bar housings 37 arranged in the x direction. One cover 34 is arranged on each side of the gas exhaust duct 234 in the y direction.

[0064] 5 and 6, when the signal processing circuit 45 in the detection circuit group is arranged outside the gas exhaust duct, a cutout is formed in part of the cover 34, and the flexible wiring board 40 or the harness is led from this cutout to the signal processing circuit 45 arranged outside the gas exhaust duct. Thereafter, the signal processing circuit 45 is covered and protected by the protective cover 47.

[0065] In the comparative example shown in FIG. 3 and the like, a busbar case 35 is present, and therefore the cover 34 and the like can be attached to the busbar case 35. However, in the embodiment of the present invention, there is no busbar case 35 separate from the spacer, and therefore the cover 34 is connected to the spacers 21 and 22. There are various methods for connecting the cover 34 to the spacers 21 and 22, such as bolt fastening or claw locking. By providing a means for fixing the cover 34 to the spacers 21 and 22, the number of parts can be reduced, leading to cost savings. [Explanation of symbols]

[0066] REFERENCE SIGNS LIST 1...battery cell, 2...battery can, 3...battery lid, 4...positive terminal, 5...negative terminal, 6...gas release valve bolt, 7...filling plug, 10...battery pack, 11...block, 20...spacer, 21...spacer, 22...spacer, 24...side rail, 25...side rail, 26...end plate, 27...end plate, 31a...bus bar, 31b...bus bar, 31c...bus bar, 35...bus bar case, 36...detection circuit housing, 37...bus bar housing, 40...flexible wiring board, 41...wiring, 45...signal processing circuit, 47...circuit board protective cover, 50...U-shaped portion, 60...partition wall, 61...low height partition wall, 70...rib, 80...spacer side cover, 90...end plate, 233...gas release hole, 234...Gas exhaust duct

Claims

1. A battery pack in which a plurality of rectangular battery cells are stacked in a first direction, first spacers each having a rectangular outer shape and second spacers each having a rectangular outer shape are alternately arranged between the plurality of battery cells; the first spacer has a first side extending in a second direction perpendicular to the first direction; a first U-shaped portion having a U-shaped cross section and extending in the first direction is formed on the first side; a first partition wall extending in the second direction is formed on the outer side of the first U-shaped portion in the second direction; the second spacer has a second side extending in the second direction; a second U-shaped portion having a U-shaped cross section and extending in the first direction is formed on the second side; a bus bar accommodating portion is formed between the first partition wall formed on the first spacer and another first partition wall formed on another first spacer adjacent to the first spacer in the first direction with the second spacer interposed therebetween; the first U-shaped portion and the second U-shaped portion are formed continuously in the first direction to form a wiring accommodating portion extending in the first direction.

2. The battery pack according to claim 1 , wherein the bus bar accommodating portion is defined in the second direction by the first U-shaped portion and the second U-shaped portion.

3. the first spacer has a first rib at an end in the second direction; the second spacer has a second rib at an end in the second direction; The battery pack according to claim 1 , wherein the bus bar accommodating portion has an end portion in the second direction defined by the first rib and the second rib.

4. the first spacer is formed as an integral part made of resin, 4. The battery pack according to claim 1, wherein the second spacer is formed as an integral part made of resin.

5. a gas exhaust duct extending in the first direction is formed to cover the plurality of battery cells, the first spacer, and the second spacer; 4. The battery pack according to claim 1, wherein, in the second direction, the wiring accommodating portion is formed outside the gas exhaust duct, and the bus bar accommodating portion is formed outside the wiring accommodating portion.

6. 4. The battery pack according to claim 1, wherein a height of the first partition wall in a third direction perpendicular to the first direction and the second direction is the same as a height of the first U-shaped portion and the second U-shaped portion.

7. 4. The battery pack according to claim 1, wherein there is no busbar case that is independent as a single component and has a plurality of the busbar housing portions and the wiring housing portion.

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