Battery pack

Abstract

The invention realizes a battery pack without a bus box. A battery pack in which a plurality of battery cells are stacked in a first direction, a first separator or a second separator being disposed between the plurality of battery cells; the first partition plate is provided with a first side extending in the second direction, a first U-shaped part extending in the first direction is formed on the first side, and a first partition wall is formed on the outer side of the first U-shaped part in the second direction. The second partition plate is provided with a second edge extending in the second direction, and a second U-shaped part with a U-shaped section and extending in the first direction is formed on the second edge; a bus accommodating portion is formed between a first partition wall formed on the first partition plate and another first partition wall formed on another first partition plate, another first partition plate is adjacent to the first partition plate 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 wiring accommodating portion extending in the first direction.

Description

Technical Field

[0001] The present invention relates to the structure of a busbar accommodating portion and a wiring accommodating portion for arranging a voltage detection line in a battery pack formed by stacking a plurality of battery cells. Background Art

[0002] Conventional battery packs use busbar boxes as busbar storage parts and dedicated storage components for voltage detection lines. Patent document 1 describes a structure in which a busbar box corresponding to the shape of the battery pack is arranged on a battery pack with stacked batteries. Patent document 2 describes a structure in which a flexible wiring substrate is used instead of a wiring harness as a voltage detection line. Prior art literature Patent Literature

[0003] Patent Document 1: Japanese Patent Application Laid-Open No. 2018-26203 Patent Document 2: Japanese Patent Application Laid-Open No. 2015-22965 Summary of the invention Technical problem to be solved by the invention

[0004] The bus box requires a new design for the structure of each new battery pack, which has a significant impact on cost. Technical means of solving problems

[0005] The present invention solves the above-mentioned problems, and its main structure is as follows.

[0006] (1) A battery pack is formed by a plurality of batteries having a rectangular shape along a first direction. A first partition with a rectangular shape or a second partition with a rectangular shape is arranged between the multiple batteries, the first partition has a first side extending in a second direction perpendicular to the first direction, a first U-shaped portion with a U-shaped cross section extending along the first direction is formed on the first side, in the second direction, a first partition wall extending in the second direction is formed at a position further outward than the first U-shaped portion, the second partition has a second side extending in the second direction, a second U-shaped portion with a U-shaped cross section extending in the first direction is formed on the second side, a busbar accommodating portion is formed between the first partition wall formed on the first partition and other first partition walls formed on other first partitions, the other first partitions are adjacent to the first partition in the first direction, the first U-shaped portion and the second U-shaped portion are continuously formed in the first direction to form a wiring accommodating portion extending along the first direction.

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

[0008] (3) The battery pack described in (1) is characterized in that the first partition has a first rib at the end in the second direction, the second partition has a second rib at the end in the second direction, and the busbar accommodating portion is divided into an end in the second direction by the first rib and the second rib. Effects of the Invention

[0009] The present invention can ensure the configuration structure of the wiring such as the voltage detection line even if a bus box independent of the partition is not used. Alternatively, even if a bus box independent of the partition is not used, a bus accommodating portion for accommodating the connection structure of each bus bar can be formed. Therefore, the cost of the battery module can be reduced. Alternatively, compared with the case of using a bus box independent of the partition, the stress caused by the thermal expansion difference between the bus box and the battery stacking structure can be suppressed, thereby improving the reliability of the battery module. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a three-dimensional diagram of a battery. Figure 2 It is a perspective view of the appearance of a battery pack in a comparative example. Figure 3 It is an exploded perspective view of a battery pack in a comparative example. Figure 4 It is a top view of the busbar box in the comparative example. Figure 5 It is a plan view showing a state where bus bars and wiring are accommodated in a bus bar box of a comparative example. Figure 6 is a perspective view of a battery pack including a signal processing circuit protection housing. Figure 7 It is a perspective view showing a busbar accommodating portion and a wiring accommodating portion of the first embodiment. Figure 8 This is an enlarged perspective view showing a busbar accommodating portion and a wiring accommodating portion in the first embodiment. Fig. 9 This is a perspective view of the battery pack of Example 1. DETAILED DESCRIPTION

[0011] The present invention is described in detail below through embodiments. The present invention is characterized in that a busbar box can be omitted. First, a structure using a busbar box as a comparative example is described. The structure of the comparative example can also be applied to the structure of the present invention except for the busbar.

[0012] Figure 1 is a three-dimensional diagram of the battery unit 1. Figure 1As shown, the battery cell 1 includes: a battery can 2, a battery cover 3, a positive terminal 4, a negative terminal 5, a gas exhaust valve 6, a liquid injection plug 7, and an electrolyte, a charging and discharging element, and an insulating shell (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 battery cell of a battery pack of one embodiment of the present invention.

[0013] The battery can 2 has a rectangular shape with one end of the internal space opened, and is made of aluminum or aluminum alloy. The battery can 2 has a pair of opposing side plates 2a with a larger area, a pair of opposing side plates 2b with a smaller area, and a bottom plate 2c on the side opposite to the opening. The charge-discharge element is contained in the internal space of the battery can 2 in a state covered by an insulating shell, and an electrolyte is injected. The positive electrode of the charge-discharge element is connected to the positive terminal 4, and the negative electrode of the charge-discharge element is connected to the negative terminal 5.

[0014] The battery cover 3 has the same rectangular flat plate shape as the bottom plate 2c, is made of aluminum or aluminum alloy, and closes the opening of the battery can 2. The battery cover 3 is joined to the opening of the battery can 2 by a joining method such as laser welding. The battery cover 3 is formed with a liquid injection hole (not shown) through which electrolyte is injected, and the liquid injection hole is closed by a liquid injection plug 7.

[0015] A gas discharge valve 6 is provided in the center of the battery cover 3. When the battery cell 1 generates heat and gas due to abnormality such as overcharging, and the pressure inside the battery can 2 rises to a predetermined pressure, the gas discharge valve 6 ruptures and discharges gas from the container to reduce the pressure inside the battery can 2.

[0016] In addition, through holes (not shown) are formed at one end and the other end of the battery cover 3, and a positive terminal 4 and a negative terminal 5 are installed. The portions of the positive terminal 4 and the negative terminal 5 exposed to the outside from the battery cover 3 are respectively formed in a rectangular parallelepiped and have a flat top surface. The power generated by the battery cell 1 is supplied to an external device via the positive terminal 4 and the negative terminal 5, or the power generated externally is supplied to the charging and discharging element via the positive terminal 4 and the negative terminal 5 for charging.

[0017] Figure 2 1 is a perspective view showing the appearance of a battery pack in a comparative example. The battery pack 10 is mounted on, for example, a hybrid vehicle driven by an internal combustion engine and an electric motor or an electric vehicle driven by an electric motor and is used as a driving source for the electric motor. Figure 2 As shown, the battery pack 10 has a block 11 and a bus box assembly 12 .

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

[0019] The partition 20 is made of a synthetic resin having insulating properties, such as Figure 3 As shown, the separators 20 are alternately sandwiched between adjacent battery cells 1 and stacked along the x direction (also referred to as the first direction) together with the battery cells 1. Both sides of each separator 20 have recesses corresponding to the shape of the battery cells 1, and the battery cells 1 are held by the recesses, and the positions in the y direction (also referred to as the second direction) and the z direction (also referred to as the third direction) are restricted.

[0020] The end plate 26 is formed of a plate-like member made of aluminum die casting. Figure 3 Although omitted in the figure, there is a partition plate 21 between the end plate 26 and the battery cell 1, and it is arranged along the stacking direction of the battery cell 1. The end plate 26 has a fixing portion, and the fixing portion is formed with fixing bolt holes for fixing the side rails 24 and the side rails 25.

[0021] The end plate 26 has fixing bolt holes and gas exhaust pipe fixing holes. The fixing bolt holes correspond to the fixing parts that fix the battery pack, and the gas exhaust pipe fixing holes correspond to the gas exhaust pipes that exhaust gas from the battery cells to the outside of the battery pack.

[0022] The end plate 27 is formed in the same manner as the end plate 26. Figure 3 Although omitted in the figure, a partition plate 21 is present between the end plate 27 and the battery cell 1, and is arranged along the stacking direction of the battery cell 1. The end plate 27 is also formed with a fixing bolt hole for fixing the battery pack 10, a negative electrode connection terminal, and a fixing hole for a gas exhaust pipe. The end plate 26, the end plate 27, the side rails 24, and the bent portions 24b and 25b of the side rails 25 are fastened by bolts 28.

[0023] The side rails 24 press and hold the end plates 26, the plurality of battery cells 1, the plurality of partitions 21, and the end plates 27 in the stacking direction. The side rails 24 have a connecting portion 24c and a bent portion 24b. Bolts 28 are inserted into the fixing holes 24a of the bent portion 24b to fix the side rails 24 to the end plates 26 and 27.

[0024] The side rail 25 is mirror-symmetrical to the side rail 24 and has the same structure. The side rail 25 is formed 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 to the side rail 24 in the y direction with the stacked battery cells 1 sandwiched therebetween, and has: a rail body 25c extending in the x direction; and bent portions 25b bent at both ends of the rail body 25c in the x direction and facing each other. The bent portion 25b has a fixing hole 25a for inserting a bolt 28.

[0025] exist Figure 3 In the embodiment, the busbar box assembly 12 includes a busbar 31, two busbar boxes 35, a gas exhaust pipe 234, two covers 34 and a busbar box 35. Figure 3 Although omitted, a wiring harness including a voltage detection line and a flexible wiring substrate are included in the busbar box assembly 12 .

[0026] exist Figure 3 In Figure 4 As shown, the bus bar 31 includes an inter-cell bus bar 31a, a negative bus bar 31b, and a positive bus bar 31c, and each component is accommodated in a frame formed on a bus bar box 35. The inter-cell bus bar 31a has a structure for electrically connecting the positive terminal 4 of the battery cell 1 and the negative terminal 5 of another adjacent battery cell 1. The negative bus bar 31b and the positive bus bar 31c are connected to external terminals.

[0027] exist Figure 3 and Figure 4 In the embodiment, the busbar box 35 has a detection circuit accommodating portion 36 for accommodating a detection circuit group. The detection circuit group may be, for example, a wiring harness (hereinafter referred to as a "wiring harness") including a wiring group for measuring the voltage and temperature of the battery, or a flexible wiring substrate for the same purpose. In addition, in the present specification, in the case of the so-called detection circuit group, a terminal portion, a wire portion, a sensor portion, and a connector portion are sometimes included. The sensor portion contacts the battery cover 3, measures the temperature of the battery cover 3, and outputs the measurement result.

[0028] The gas exhaust pipe 234 has a gas exhaust port 233, which is used to isolate and collect the gas exhausted from the gas exhaust valve 6 to the center of the y direction, and then discharge it from the gas exhaust port 233. The gas exhaust pipe 234 is fixed to the internal threads of the first end plate 26 and the second end plate 27 by screws arranged at both ends in the x direction. The two covers 34 have the function of insulating and protecting the constituent elements of the bus box assembly 12, and are arranged to cover the busbar 31 and the detection circuit group. Each cover 34 is embedded and fixed on the bus box 35. The bus box 35 has a frame for forming a plurality of busbar accommodating portions 37 arranged along the stacking direction of the battery cell 1, and the inter-cell busbar 31a, the negative busbar 31b, and the positive busbar 31c are respectively accommodated in the frame.

[0029] Figure 4 This is a top view of the busbar box 35 as seen from above. Figure 4 In the embodiment, the gas exhaust pipe 234 extends in the x direction at the center in the y direction, and the busbar box 35 is arranged in the y direction to sandwich the gas exhaust pipe 234. In each busbar box 35, busbar accommodating portions 37 are arranged in the x direction, and the busbar accommodating portions 37 respectively accommodate the inter-unit busbar 31a, the negative busbar 31b, and the positive busbar 31c.

[0030] In addition, a detection circuit accommodating portion 36 for accommodating a detection circuit group is formed on each busbar box 35. Here, the detection circuit group can be a wire harness or a flexible circuit board. In addition, the detection circuit may be arranged on the gas exhaust pipe 234, for example.

[0031] Figure 5 FIG. 4 is a top view showing a case where a flexible wiring substrate 40 is used in a detection circuit group. Figure 5 In the embodiment, the busbar box 35 and the gas exhaust pipe 234 are as shown in Figure 4 As described in . A flexible wiring substrate 40 is arranged in the detection circuit accommodating portion 36. A plurality of wirings 41 formed on the flexible wiring substrate 40 are connected to the bus bars 31a, 31b, and 31c, respectively, and the detected voltage is sent to the signal processing circuit 45. In addition, in order to detect the temperature, a signal from a thermistor or the like in contact with the battery is sent to the signal processing circuit 45.

[0032] exist Figure 5 In the embodiment, the signal processing circuit 45 is arranged on the gas exhaust pipe 234. The signal processing circuit 45 processes the voltage of the battery, the signal from the thermistor, etc., and performs necessary control. In addition, in the signal processing for performing necessary control, when the circuit scale becomes large, sometimes the signal is sent to the outside by wireless, and the control signal is generated by the signal processing circuit arranged outside, and then it is taken in again by wireless.

[0033] exist Figure 5 In the embodiment, the signal processing circuit 45 is arranged on the gas exhaust pipe 234. Therefore, in order to protect the signal processing circuit 45, as shown in FIG. Figure 6 As shown, a circuit board protection cover 47 is used. As a specific configuration, for example, a cutout is formed on a portion of the cover 34, and a portion of the flexible wiring board 40 is led out to the outside from the cutout portion and arranged on the discharge duct 234. The flexible wiring board 40 exposed to the outside is protected by the circuit board protection cover 47. The circuit board protection cover 47 is formed of an insulating material such as resin.

[0034] exist Figure 5In the embodiment, the wiring 41 for taking in signals and the signal processing circuit 45 are both formed on the same flexible wiring substrate 40. The flexible wiring substrate 40 formed with the wiring 41 is present at the bottom of the detection circuit accommodating portion 36, and the signal processing circuit 45 is arranged above the gas exhaust pipe 234, so a height difference is formed. However, the flexible wiring substrate 40 formed of a resin such as polyimide as a base material can flexibly cross the height difference. In addition, each wiring 41 formed on the flexible wiring substrate 40 is branched and connected to each bus bar 31, but if each wiring 41 is branched together with the resin such as polyimide as a base material, it is mechanically stronger.

[0035] exist Figure 5 In the embodiment, the signal processing circuit 45 is arranged on the gas exhaust duct 234, but the signal processing circuit may be arranged in each detection circuit accommodating portion according to the layout of the flexible wiring substrate 40. In this case, since the circuit scale cannot be increased in terms of space, data is often sent to the signal processing circuit arranged outside and a control signal is generated.

[0036] The above structure is a case where the detection circuit group is composed of a flexible wiring substrate 40, but the same is true for a case where it is formed by a harness. When the detection circuit group is composed of a harness, although it occupies more space than the case of a flexible wiring substrate, the same structure can be basically adopted. The structure of the detection circuit group described above can also be applied to the structure of the embodiment of the present invention described in Example 1, which does not have a bus box.

[0037] exist Figures 3 to 5 In the example, two bus boxes are used. The size of the bus box 35 is the same as that of the block 11 as the battery stack at least in the x direction, and the outer shape is large, so it takes time to develop. The bus box may sometimes be composed of one, but it is basically the same. In addition, the manufacturing cost of the bus box 35 is also high. Furthermore, if the bus box 35 and the block 11 as the battery stack have different thermal expansion coefficients, consider the situation in which stress is generated on the components when the temperature of the battery pack rises. The structure described in the following embodiment is to improve this point, and is a structure that can accommodate the busbar without using a bus box 35 independent of the partition. Example 1

[0038] Figure 7 1 is an exploded perspective view of a block 11 as a stack of batteries according to Embodiment 1. Embodiment 1 is characterized in that the busbar box can be omitted. Figure 7 As shown, in the first embodiment, the detection circuit accommodating portion 36 and the bus bar accommodating portion 37 are formed by the shapes of the plurality of partition plates 21 and 22 in the block.

[0039] exist Figure 7In the embodiment, a plurality of battery cells 1 are stacked in the x direction with the first separator 21 or the second separator 22 therebetween. The separators 21 and 22 alternately separate the battery cells 1 in the x direction. The separators 21 and 22 have the same structure except that the positions of the partition walls 60 constituting the busbar accommodating portion 37 are different. Each of the separators 21 and 22 has a side cover 80, and the battery cells 1 are accommodated in the space formed by the side cover 80 abutting against it.

[0040] Except for the different positions of the partition wall 60, the partition 21 and the partition 22 have the same structure, so the partition 21 will be mainly described. Two wiring accommodating portions 50 with U-shaped cross-sections are formed at the upper ends of the partitions 21 and 22. The U-shaped portion extends along the +y direction of the partition. Multiple U-shaped portions are arranged at intervals. The wiring accommodating portion 50 is formed at a position that is line-symmetrical with respect to the center line of the partition in the y direction. Since the wiring accommodating portion 50 is formed at the same position on the partition 21 and the partition 22, if the partitions 21, 22 and the battery cell 1 are stacked in the x direction, a detection circuit accommodating portion 36 such as a U-shaped groove extending in the x direction is formed.

[0041] exist Figure 7 In the embodiment, the separator 21 and the separator 22 are continuously stacked in the x direction with the battery cell 1 sandwiched therebetween. A rib 70 is formed near the end of the separator in the +y direction. The ribs 70 are stacked in a manner of abutting against each other in the x direction to form a substantially continuous cofferdam. The end of the separator in the +y direction is divided by each rib 70 of the adjacent separator.

[0042] Near the end in the +y direction, a partition wall 60 is formed between the rib 70 and the wiring accommodating portion 50 having a U-shaped cross section (hereinafter also referred to as the "U-shaped portion 50"). The partition wall 60 is a portion of the partition 21. On the other hand, in this portion, the partition wall 60 is not formed on the partition 22 adjacent to the partition 21 in the +x direction. The partition wall 60 is formed on the partition 21 further adjacent to the partition 22 in the +x direction. Therefore, at the end in the +y direction, a space surrounded by the U-shaped portion 50, the partition wall 60, and the rib 70 is formed. In Example 1, this space is used as the busbar accommodating portion 37. Figure 7 In the embodiment, the busbar accommodating portions 37 are partitioned by the partition walls 60 at the ends of the partition plates 21 and 22 in the +y direction, and are continuously arranged in the x direction.

[0043] exist Figure 7 In the embodiment, in the vicinity of the end in the -y direction, the partition wall 60 is formed on the partition plate 22, but the partition wall 60 is not formed on the partition plate 21. Therefore, in the vicinity of the end in the -y direction, the busbar accommodating portion 37 is formed between the partition wall 60 formed on the partition plate 22 and the partition wall 60 formed on the other partition plate 22. In addition, in the vicinity of the end in the -y direction, the busbar accommodating portion 37 is formed by the U-shaped portion 50, the partition wall 60 and the rib 70, which is the same as the +y side.

[0044] exist Figure 7 In FIG. 1 , if the x-direction pitch of the busbar housing portions 37 is px, the busbar housing portions 37 formed in the +y direction and the busbar housing portions 37 formed in the -y direction are offset by px / 2 in the x direction. Figure 7 In the embodiment, the positive terminal 4 of the battery cell 1 and the negative terminal 5 of another battery cell 1 are accommodated in the busbar accommodation portion 37. Figure 7 As shown, the positive electrode terminal 4 and the negative electrode terminal 5 are connected by the bus bar 31 a in the bus bar housing portion 37 .

[0045] like Figure 7 As described in , near the end in the +y direction, the busbar housing portion 37 separated by the partition wall 60 is continuously formed in the x direction, and near the end in the -y direction, the busbar housing portion 37 separated by the partition wall 60 is continuously formed in the x direction. Figure 7 There are also Figure 3 The busbar receiving portion 37 formed on the two busbar boxes shown in the figure has the same structure. Figure 3 The detection circuit accommodating portions formed on the two bus boxes 35 shown are also implemented by two rows of U-shaped portions.

[0046] Thus, by using Figure 7 Even if the bus box 35 is not used, the same structure can be formed by simply changing the shape of the upper part of the partitions 21 and 22. Therefore, the manufacturing cost of the bus box 35 can be saved, and the development period of the bus box 35 can also be omitted. Furthermore, the stress of the battery when it is operating and when it is not operating caused by the difference in thermal expansion coefficient between the block 11 composed of the stacked battery cells 1 and the bus box 35 can be eliminated, so that the reliability can be improved.

[0047] exist Figure 7 In the embodiment, a U-shaped portion 50, a partition wall 60, a rib 70, etc. are formed on the upper portion of the partitions 21 and 22 in the z direction, making the shape slightly complicated. However, the partitions 21 and 22 are formed of resin and molded by a mold. The partitions 21 and 22 can be provided as an integral part of the resin. That is, the mold can be designed and manufactured once and can be used repeatedly thereafter. Therefore, the manufacturing cost does not increase.

[0048] In addition, the partition 21 and the partition 22 have different shapes, but the only difference is the portion of the partition wall 60. Figure 7 In the partition 21, the partition wall 60 is formed near the end in the +y direction, but the partition wall 60 is not formed near the end in the -y direction. On the other hand, in the partition 22, the partition wall 60 is not formed near the end in the +y direction, but the partition wall 60 is formed near the end in the -y direction.

[0049] That is, the partition 21 and the partition 22 are linearly symmetrical with respect to the z-axis including the center of the y-direction. Therefore, the partition 21 and the partition 22 are formed by the same mold, and when used, the partition 21 and the partition 22 can be used in a state of being turned left and right. That is, even if there are partitions 21 and 22, since the manufacturing can be formed by a single mold, the manufacturing cost does not increase.

[0050] Figure 7 36. The bus bar 31a is also shown in a state where the bus bar 31a is installed in the bus bar housing portion 37, and a stereoscopic view of a state where the flexible wiring substrate 40 is arranged in the detection circuit housing portion 36. The bus bar 31a is bonded by, for example, butt welding of a phosphor bronze plate and an aluminum or aluminum alloy plate. It is joined to the aluminum as the positive terminal 4 of the battery cell 1 and the copper as the negative terminal. The bus bar 31a is mounted on the positive terminal 4 and the negative terminal 5 of the battery cell 1 by laser welding, riveting, etc. In addition, a voltage detection terminal is formed on the bus bar 31a, and is connected to the wiring branched from the flexible wiring substrate 40 arranged in the detection circuit housing portion 36.

[0051] exist Figure 7 , the flexible wiring substrate 40 is shown to be arranged in the detection circuit accommodating portion 36 formed by the U-shaped portion 50. In the flexible wiring substrate 40, a plurality of wirings 41 extending in the x direction are formed, and each wiring 41 is branched and connected to a voltage detection terminal formed on the bus bar 30a. In addition, the wirings 41 formed on the flexible wiring substrate 40 also include wirings for connecting to the thermistor mounted on the battery cell 1.

[0052] The general shape of the flexible wiring substrate 40 is similar to Figure 5 The flexible wiring substrate 40 in FIG. Figure 5 In the embodiment, the flexible wiring substrate 40 is arranged in the detection circuit accommodating portion 36 formed on the busbar box 35, and in contrast, Figure 7 The busbar box 35 is not present, and the flexible wiring substrate 40 is arranged in the detection circuit accommodating portion 36 formed by the U-shaped portion 50 formed on the partition plates 21 and 22 .

[0053] exist Figure 7 In Figures 3 to 6 As shown, the gas exhaust pipe 234 is arranged in a manner to cover the gas exhaust valve 6 of the battery cell 1. In addition, Figures 3 to 6 The cover 34 shown directly covers the detection circuit accommodating portion 36 and the busbar accommodating portion 37 formed by the U-shaped portion 50. Figure 5 As shown, the signal processing circuit in the detection circuit group is arranged on the gas exhaust pipe.

[0054] That is, Figure 5 and Figure 6As described in the above, a cutout is formed in a part of the cover 34, and a part of the flexible wiring substrate 40 including the signal processing circuit 45 is arranged on the gas exhaust duct 234. Then, the signal processing circuit 45 is covered by the protective cover 47. Figure 7 In the structure, the appearance of the battery module is Figure 6 same.

[0055] However, in Figure 7 In the case where a flexible wiring substrate 40 is used as a detection circuit group, the same applies to the case where a wiring harness arranged in a detection circuit accommodating portion 36 formed by a U-shaped portion 50 is used instead of the flexible wiring substrate 40. That is, instead of the flexible wiring substrate 40, the wiring harness is arranged in the detection circuit accommodating portion 36 formed by the U-shaped portion 50. And, each conductor of the wiring harness is connected to a voltage detection terminal formed on the bus bar 31a. On the other hand, the signal processing circuit 45 is also arranged on the gas exhaust duct 234. In the case of the wiring harness, the signal processing circuit 45 is additionally formed on the gas exhaust duct 234. Then, the signal processing circuit 45 is covered by a protective cover 47. Compared with the case of the flexible wiring substrate, the wiring volume of the wiring harness becomes larger, but the basic appearance of the battery module is the same. Figure 6 Same as shown.

[0056] Figure 8 FIG. 1 is an enlarged perspective view of a block 11 as a stack of battery cells 1 in Example 1. The basic structure of the block 11 is similar to Figure 7 That is, a U-shaped portion 50 is formed at the upper end of the partitions 21 and 22 to form a detection circuit accommodating portion 16, and a busbar accommodating portion 37 is formed in an area surrounded by the U-shaped portion 50, the partition wall 60, and the rib 70. With this structure, the busbar 31a and the voltage detection terminal mounted on the busbar 31a can be protected.

[0057] exist Figure 8 , the height h1 of the partition wall 60 is the difference between the height of the partition plate in the z direction at the portion without the partition wall 60 and the height of the partition plate in the z direction at the portion with the partition wall 60. The height h1 of the partition wall 60 may be the same as the height h1 of the U-shaped portion 50.

[0058] exist Figure 8 In the embodiment, the U-shaped portion 50 is arranged at a position higher than the position where the bus bar 31a is mounted in the z direction. As a result, it is easy to connect the wiring branched from the flexible wiring substrate 40 arranged in the detection circuit accommodating portion 36 formed by the U-shaped portion 50 and the voltage detection terminal mounted on the bus bar 31a. The same is true when the detection circuit group is formed not by the flexible wiring substrate 40 but by a wiring harness.

[0059] exist Figure 8In the embodiment, the positive terminal 4 of the battery and the negative terminal 5 of another battery are present in the busbar accommodating portion 37 separated by the partition wall 60, and the positive terminal 4 and the negative terminal 5 are connected by the busbar 31. The positive terminal 4 and the negative terminal 5 are separated by the partition plate 22. However, depending on the requirement for installing the busbar 31a, a partition wall 61 having a height lower than the partition wall 60 is sometimes configured. However, in this case, the partition wall 61 is preferably lower than the height of the busbar 31a.

[0060] Fig. 9 9 is a perspective view showing a state where a plurality of battery cells 1 are stacked in the x direction with a separator 21 or a separator 22 therebetween. The stacked battery cells 1 are held by end plates 90. A gas discharge valve 6 is disposed in the center of each battery cell 1 in the y direction. Therefore, the gas discharge valves 6 are arranged at a certain interval in the x direction. Figure 3 The gas exhaust pipe 234 shown in the figure is arranged to cover the queue of the gas exhaust valves.

[0061] exist Fig. 9 In the embodiment, on both sides of the gas exhaust valve array in the y direction, a detection circuit accommodating portion 36 is formed by a U-shaped portion 50 formed on the partition 21 and the partition 22. The detection circuit accommodating portion 36 extends in the x direction. Fig. 9 In the embodiment, the busbar housing portion 37 is formed outside the detection circuit housing portion 36. The busbar housing portion 37 is divided by a partition wall 60 formed on the partition plate 21 on the +y direction side, and the busbar housing portion 37 is divided by a partition wall 60 formed on the partition plate 22 on the -y direction side.

[0062] If the x-direction pitch of the busbar housing 37 is px, the position of the busbar housing 37 on the +y side is offset from the position of the busbar housing 37 on the -y side by px / 2 in the x-direction. The positive terminal 4 of the battery cell 1 and the negative terminal 5 of the adjacent battery are housed in each busbar housing 37. The positive terminal 4 and the negative terminal 5 are connected by the busbar 31a using laser welding, riveting, or the like.

[0063] exist Fig. 9 In the detection circuit storage unit 36, there is a Figure 7 The detection circuit wiring 40 shown. The detection circuit wiring can be a flexible wiring substrate 40 or a wire harness. In any case, each wiring 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 accommodating portion 37. Then, Figure 3 The cover 34 shown is arranged to cover the detection circuit housing portion 36 extending in the x direction and the bus bar housing portion 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] and Figure 5 and Figure 6As described in , when the signal processing circuit 45 in the detection circuit group is arranged outside the gas exhaust duct, a cutout is formed in a part of the cover 34, and the flexible wiring substrate 40 or the wiring harness is guided from the cutout to the signal processing circuit 45 arranged outside the gas exhaust duct. Then, the signal processing circuit 45 is covered and protected by the protective cover 47.

[0065] As a comparative example Figure 3 In the embodiment of the present invention, since there is a bus box 35, it is sufficient to install the cover 34 on the bus box 35. However, in the embodiment of the present invention, since there is no bus box 35 independent of the partition, the cover 34 is combined with the partitions 21 and 22. The combination method of the cover 34 and the partitions 21 and 22 includes various means such as bolt fastening and claw locking. By providing a fixing mechanism for the cover 34 on the partitions 21 and 22, the number of parts can be reduced and the cost can be reduced. Explanation of symbols

[0066] 1…battery cell, 2…battery can, 3…battery cover, 4…positive terminal, 5…negative terminal, 6…gas discharge valve bolt, 7…injection plug, 10…battery pack, 11…block, 20…partition plate, 21…partition plate, 22…partition plate, 24…side guide rail, 25…side guide rail, 26…end plate, 27…end plate, 31a…bus bar, 31b…bus bar, 31c…bus bar, 35…bus bar box, 36…detection circuit accommodating portion, 37…bus bar accommodating portion, 40…flexible wiring substrate, 41…wiring, 45…signal processing circuit, 47…circuit substrate protection cover, 50…U-shaped portion, 60…partition wall, 61…low height partition wall, 70…rib, 80…side cover of partition plate, 90…end plate, 233…gas discharge hole, 234…gas discharge duct.

Claims

1. A battery pack, which is formed by stacking a plurality of battery cells with a rectangular shape along a first direction, wherein the battery pack is characterized in that: A first separator having a rectangular shape or a second separator having a rectangular shape is arranged between the plurality of battery cells. The first partition 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 along the first direction is formed on the first side. In the second direction, a first partition wall extending in the second direction is formed at a position further outward than the first U-shaped portion. The second partition has a second side extending along the second direction, A second U-shaped portion having a U-shaped cross section and extending along the first direction is formed on the second side. A busbar accommodating portion is formed between the first partition wall formed on the first partition plate and another first partition wall formed on another first partition plate, wherein the other first partition plate is adjacent to the first partition plate in the first direction. The first U-shaped portion and the second U-shaped portion are continuously formed in the first direction to form a wiring accommodating portion extending in the first direction.

2. The battery pack according to claim 1, characterized in that: The bus bar housing portion is divided by the first U-shaped portion and the second U-shaped portion in the second direction.

3. The battery pack according to claim 1, characterized in that: The first partition plate has a first rib at an end portion in the second direction, The second partition plate has a second rib at an end portion in the second direction, The busbar accommodating portion has an end portion in the second direction divided by the first rib and the second rib.

4. The battery pack according to any one of claims 1 to 3, characterized in that: The first separator is formed as an integral member made of resin. The second separator is formed as an integral member made of resin.

5. The battery pack according to any one of claims 1 to 4, characterized in that: A gas exhaust duct extending in the first direction is formed to cover the plurality of battery cells, the first separator, and the second separator, In the second direction, the wiring accommodating portion is formed outside the gas exhaust duct, and the busbar accommodating portion is formed outside the wiring accommodating portion.

6. The battery pack according to any one of claims 1 to 5, characterized in that: The height of the first partition wall in a third direction perpendicular to the first direction and the second direction is the same as the heights of the first U-shaped portion and the second U-shaped portion.

7. The battery pack according to any one of claims 1 to 6, characterized in that: There is no bus bar box having a plurality of the bus bar accommodating portions and the wiring accommodating portions that is independent as a single component.

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