Battery module

Abstract

This invention provides a battery module that can output power without replacing any faulty battery cells, even if some of them malfunction. [Solution] The battery comprises three or more battery cells 20 having positive terminals 24 and negative terminals 26, and a plurality of conductive busbars 30 that connect the positive terminal of one of two adjacent battery cells to the negative terminal of the other, with fastening portions provided on the busbars for mechanically fastening bypass members 50 which are made of a different material from the busbars and are conductive.

Description

Technical Field

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

Background Art

[0002] Patent Document 1 below discloses a battery module including a plurality of battery cells. All the battery cells included in the battery module are electrically connected to adjacent battery cells by bus bars.

Prior Art Document

Patent Document

[0003] [[ID=2①]]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] For example, in the battery module of Patent Document 1 above, when an abnormality occurs in one battery cell, power cannot be taken out from the battery module. If the bus bar is removed from the one battery cell in which the abnormality has occurred and a new battery cell is connected to this bus bar, power can be taken out from the battery module. However, such work is not easy.

[0005] In consideration of the above facts, an object of the present invention is to obtain a battery module capable of outputting power without replacing the battery cell in which an abnormality has occurred when an abnormality occurs in some of the battery cells.

Means for Solving the Problems

[0006] The battery module of the first embodiment comprises three or more battery cells having positive and negative terminals, and a plurality of conductive busbars connecting the positive terminal of one of two adjacent battery cells to the negative terminal of the other, wherein the busbars are provided with fastening portions for mechanically fastening bypass members that are different from the busbars and are conductive.

[0007] In the battery module of the first embodiment, the positive terminal of one battery cell and the negative terminal of the other of two adjacent battery cells are connected by a busbar. If a malfunction occurs in one of the adjacent battery cells, which are connected to two adjacent battery cells by two busbars, a conductive bypass member is mechanically fastened to the fastening portion of the two busbars connected to the two adjacent battery cells. As a result, electricity flows between the two adjacent battery cells while bypassing the malfunctioning battery cell, allowing the battery module to output power. Therefore, the battery module of the first embodiment can output power without replacing the malfunctioning battery cell when a malfunction occurs in some of the battery cells.

[0008] In the second embodiment, the battery module, in the first embodiment, has a fastening portion which has a nut fixed to the busbar, and the bypass member has a through hole through which a bolt that can be screwed into the nut can pass.

[0009] In the battery module of the second embodiment, the bypass member can be easily fastened to the busbar fastening portion using bolts.

[0010] In the third embodiment of the battery module, in the first or second embodiment, the fastening portion is located away from the straight line connecting the connection portion of the busbar to the positive terminal and the connection portion to the negative terminal in a plan view.

[0011] In the battery module of the third embodiment, the fastening portion is less likely to affect the electrical resistance of the part of the busbar through which electricity flows.

[0012] The fourth embodiment of the battery module includes a cover member that can be attached to the busbar so as to cover the fastening portion in any of the first to third embodiments, and is detachable from the busbar.

[0013] In the fourth embodiment of the battery module, when the bypass member is not fastened to the fastening portion, the fastening portion is covered by the cover member. As a result, dust and moisture are less likely to adhere to the fastening portion.

[0014] In the fifth embodiment of the battery module, in any of the first to fourth embodiments, the busbar is provided with a connecting projection that protrudes upward.

[0015] In the fifth embodiment of the battery module, for example, a connecting device provided at the end of a discharge cable can be easily connected to a connecting projection on a busbar. [Effects of the Invention]

[0016] As described above, the battery module according to the present invention has the excellent effect of being able to output power without replacing the faulty battery cells when some of the battery cells malfunction. [Brief explanation of the drawing]

[0017] [Figure 1] This is a schematic plan view of a plurality of battery cells, busbars, and bypass members included in a battery module according to the embodiment. [Figure 2] This is a schematic plan view of the ends and busbars of two adjacent battery cells. [Figure 3] This is a schematic perspective view of a busbar, bolt, and connector. [Figure 4] This is a plan view similar to Figure 2 in the modified example. [Modes for carrying out the invention]

[0018] Hereinafter, the battery module according to the embodiment will be described while referring to the accompanying drawings. In each figure, the arrow UP, the arrow FR, and the arrow LH indicate the upper side in the vehicle up-down direction, the front side in the vehicle front-rear direction, and the left side in the vehicle left-right direction, respectively.

[0019] The battery module 10 of the present embodiment is mounted on a vehicle (electric vehicle). The vehicle of the present embodiment is a battery electric vehicle (BEV: Battery Electric Vehicle).

[0020] The battery module 10 of the present embodiment includes a battery case (not shown) supported by the vehicle body and a battery stack 15 housed inside the battery case. The battery case includes a lower case and an upper case. The battery stack 15 is provided inside the lower case and is further fixed to the bottom plate portion of the lower case. When the lower edge portion of the upper case is connected to the upper edge portion of the lower case that houses the battery stack 15 in this way and the lower case and the upper case are fixed, the battery module 10 (battery stack 15) is covered by the battery case.

[0021] The battery module 10 has a battery stack 15 shown in FIG. 1, a plurality of bus bars 30, and a bypass member 50.

[0022] The battery stack 15 includes battery cells 20 which are a large number of secondary batteries arranged in the left-right direction, a plurality of resin spacers (not shown) provided between adjacent battery cells 20, on the left side of the leftmost battery cell 20, and on the right side of the rightmost battery cell 20, and a pair of end plates (not shown) located on the left side of the leftmost spacer and on the right side of the rightmost spacer, and a restraining member (not shown) connected to the pair of end plates and pulling the two end plates in a direction approaching each other. Although only 4 battery cells 20 are depicted in FIG. 1, the actual battery stack 15 includes dozens of battery cells 20.

[0023] The metal cell case 22 that forms the outer shape of the lithium-ion battery cell 20 is approximately rectangular in shape. As shown in Figure 1, the planar shape of the cell case 22 is a rectangle in which the front-to-back dimension is larger than the left-to-right dimension. A positive electrode terminal 24 and a negative electrode terminal 26, which are external electrodes, are provided on the top surface of each cell case 22. As shown in Figure 1, each battery cell 20 is arranged in the left-to-right direction such that the positive electrode terminal 24 and the negative electrode terminal 26 are arranged alternately in the left-to-right direction.

[0024] The busbar 30, made of a conductive material such as metal, is a substantially flat plate-shaped member. The planar shape of the busbar 30 is substantially convex. That is, the busbar 30 has a conductive portion 31 that extends linearly in one direction and is substantially rectangular in plan view, a projection 32 that protrudes from the edge of the longitudinal center of the conductive portion 31, and a plate-shaped portion (connecting projection) 33 that protrudes upward from the end of the upper surface of the projection 32. A first connecting portion (connecting portion) 34 and a second connecting portion (connecting portion) 35 are provided near both ends of the conductive portion 31. A recess 36 with a hexagonal planar shape is formed on the upper surface of the projection 32. Furthermore, a nut (fastening portion) 37 made of a conductive material such as metal is provided in the recess 36, and the nut 37 is fixed to the projection 32. As shown in Figure 2, in a plan view, the nut 37 (protrusion 32, plate-shaped part 33) is separated from the band-shaped region AR (straight line) that linearly connects the first connection part 34 and the second connection part 35.

[0025] As shown in Figure 1, each busbar 30 connects the positive terminal 24 and negative terminal 26 of two adjacent battery cells 20 in the left-right direction. That is, for example, the first connection part 34 of the busbar 30 is electrically connected by welding or the like to the negative terminal 26 of the battery cell 20 located on the far right in Figure 1, and the second connection part 35 of the busbar 30 is electrically connected by welding or the like to the positive terminal 24 of the second battery cell 20 from the right. In other words, the busbar 30 is fixed to the positive terminal 24 and the negative terminal 26. Also, the second connection part 35 of the busbar 30 is electrically connected by welding or the like to the negative terminal 26 of the second battery cell 20 from the right in Figure 1, and the first connection part 34 of the busbar 30 is electrically connected by welding or the like to the positive terminal 24 of the third battery cell 20 from the right. In this embodiment, each battery cell 20 is connected in series by a number of busbars 30.

[0026] A cover bolt (cover member) 40, shown in Figure 3, can be screwed onto the nut 37 of the busbar 30. The head 41 of the cover bolt 40 is larger in diameter than the nut 37. Therefore, when the cover bolt 40 is screwed onto the nut 37 and the head 41 is brought into contact with the upper surface of the nut 37 and the upper surface of the plate-like portion 33, the entire nut 37 is covered by the head 41 (see Figure 2).

[0027] (Mechanism of action and effect) Next, the operation and effects of the embodiment will be described.

[0028] For example, when all the battery cells 20 constituting the battery stack 15 are operating normally, the power from the battery module 10 is supplied to various devices or equipment installed in the vehicle via an electrical connector (not shown) electrically connected to the battery module 10 and a harness etc. (not shown) connected to the electrical connector. For example, the power from the battery module 10 (battery cell 20) is supplied to an electric motor (not shown) that provides rotational driving force to the drive wheels.

[0029] For example, if an abnormality such as an internal short circuit occurs in any of the battery cells 20 of the battery module 10, the flow of electricity in the battery stack 15 may be interrupted by this battery cell 20 (hereinafter referred to as the abnormal battery cell 20X). Here, let's assume that the battery cell 20 indicated by reference numeral 20X in Figure 1 is the abnormal battery cell 20X. In this case, power from the battery module 10 will no longer be supplied to the above-mentioned device and equipment. Therefore, in this case, the lower case of the battery case is separated from the upper case to expose the battery stack 15. Furthermore, remove the cover bolt 40 from the nut 37 of the bus bar 30 (hereinafter referred to as the right bus bar 30R) that connects the abnormal battery cell 20X to the battery cell 20 to its right (right battery cell 20R), and remove the cover bolt 40 from the nut 37 of the bus bar 30 (hereinafter referred to as the left bus bar 30L) that connects the abnormal battery cell 20X to the battery cell 20 to its left (left battery cell 20L).

[0030] Next, connectors 42 (see Figure 3), which are provided at the ends of the harness 45 connected to the discharge device (not shown), are connected to the plate-shaped portions 33 of the left busbar 30L and the right busbar 30R. The connector 42 comprises a main body 43 and a pair of rotatable connectors 44 that are rotatable relative to the main body 43. Each rotatable connector 44 is biased to rotate toward each other by the biasing force of a spring (not shown). Therefore, the plate-shaped portion 33 can be sandwiched between the pair of rotatable connectors 44. In other words, the connector 42 can be easily connected to the plate-shaped portion 33. The rotatable connectors 44 are made of a conductive material and are connected to the harness 45 connected to the discharge device. Therefore, when the connector 42 is connected to the plate-shaped portion 33 of the left busbar 30L and the plate-shaped portion 33 of the right busbar 30R for a predetermined period of time, the power of the abnormal battery cell 20X is discharged to the discharger, and the voltage of the abnormal battery cell 20X becomes less than or equal to a predetermined value (for example, 1 volt).

[0031] When the voltage of the abnormal battery cell 20X falls below a predetermined value, the connector 42 is removed from each plate-shaped part 33, and the electrical connector is removed from the battery module 10. Next, the bypass member 50 shown in Figures 1 and 3 is connected to the plate-shaped part 33 of the left bus bar 30L and the plate-shaped part 33 of the right bus bar 30R. The bypass member 50 has a first connection part 51 and a second connection part 52 made of a conductive material such as metal, and a flexible harness 53 made of a conductive material such as metal that connects the first connection part 51 and the second connection part 52. Furthermore, a first through hole (through hole) 51A is formed in the first connection part 51, and a second through hole (through hole) 52A is formed in the second connection part 52. As shown in Figure 1, the first connection part 51 and the second connection part 52 of the bypass member 50 are placed on the upper surface of the protrusion 32 of the left bus bar 30L and the upper surface of the protrusion 32 of the right bus bar 30R, respectively. Furthermore, a bolt 55 inserted from above into the first through-hole 51A is screwed into the nut 37 on the projection 32 of the left bus bar 30L, and the head 56 of the bolt 55 is pressed against the upper surface of the first connection part 51. A bolt 58 inserted from above into the second through-hole 52A is screwed into the nut 37 on the projection 32 of the right bus bar 30R, and the head 59 of the bolt 58 is pressed against the upper surface of the second connection part 52. The electrical connector is then reconnected to the battery module 10. As a result, the left bus bar 30L and the right bus bar 30R are electrically connected by the bypass member 50 and the nut 37, and power from the battery module 10 is again supplied to the device or equipment via the electrical connector and harness. In this way, the battery module 10 can output power even if an abnormality occurs in some of the battery cells 20, namely the abnormal battery cells 20X, without replacing the abnormal battery cells 20X with new battery cells. Furthermore, there is no need to replace the entire battery module 10 with a new battery module.

[0032] Furthermore, when the busbar 30 connects the positive terminal 24 and negative terminal 26 of two adjacent battery cells 20, electricity flows through the strip-shaped region AR of the busbar 30 (see arrow in Figure 3). As described above, in a plan view, the nut 37 (recess 36), protrusion 32, and plate-shaped portion 33 are separated from the strip-shaped region AR that linearly connects the first connection portion 34 and the second connection portion 35 of the busbar 30. Therefore, the nut 37, protrusion 32, and plate-shaped portion 33 are less likely to affect the electrical resistance of the strip-shaped region AR. As a result, there is little risk of the busbar 30 generating an extremely large amount of heat due to the nut 37, protrusion 32, and plate-shaped portion 33, or of the mechanical strength of the busbar 30 decreasing due to the heat generation.

[0033] Furthermore, when the bypass member 50 is not mechanically fastened to the nut 37 of the busbar 30, the nut 37 is covered by the head 41 of the cover bolt 40. Therefore, when the bypass member 50 is not fastened to the nut 37 of the busbar 30, dust and moisture are less likely to adhere to the nut 37.

[0034] Although battery modules according to each embodiment have been described above, these can be modified as appropriate without departing from the spirit of the present invention.

[0035] For example, as shown in Figure 4, the bus bar 30 may not have a protrusion 32 and a plate-like portion 33, and a nut 37 (recess 36) may be provided in the longitudinal center of the bus bar 30 (conductive portion 31).

[0036] Regardless of whether the busbar 30 has a projection 32 and a plate-like portion 33, the fastening portion, which is the structure for mechanically fastening the busbar 30 to the bypass member 50, may be different from the nut 37. For example, the fastening portion of the busbar 30 may be a through hole that penetrates the busbar 30 in the vertical direction. In this case, for example, a bolt that passes downward through the first through hole 51A and the second through hole 52A of the bypass member 50 passes downward through the through hole of the busbar 30, a nut is screwed into the male thread groove of the bolt below the busbar 30, and this nut is pressed against the lower surface of the busbar 30 while the head of the bolt is pressed against the upper surface of the busbar 30. Alternatively, for example, a pin-shaped member made of a conductive material such as metal that passes downward through the first through hole 51A and the second through hole 52A of the bypass member 50 passes downward through the through hole of the busbar 30, and the pin-shaped member may be plastically deformed and crimped to the busbar 30 and the bypass member 50.

[0037] The fastening portion of the busbar 30 may also be an electrical connector. For example, if the fastening portion of the busbar 30 is a male connector, female connectors are provided at both ends of the harness 53 of the bypass member 50, and each female connector is connected to the male connector of the busbar 30. In this case, the male connector and the female connector may be fixed to each other using fixing means such as welding.

[0038] Instead of the cover bolt 40, the nut 37 may be covered with a plug cap.

[0039] If the fastening portion, which is a structure for mechanically fastening the bypass member 50 of the busbar 30, is a through hole, a plug member that is press-fitted into the through hole or tape that is adhered to both the upper and lower surfaces of the projection 32 so as to cover the end face of the through hole may be used instead of the cover bolt 40.

[0040] The busbar 30 may have a pin (connecting projection) instead of the plate-shaped portion 33.

[0041] The number of battery cells 20 included in the battery stack 15 can be any number, as long as it is 3 or more.

[0042] The vehicle may be an electric vehicle that is different from an electric vehicle and is equipped with an electric motor that utilizes the power of the battery module 10. For example, the vehicle may be a hybrid electric vehicle (HEV) or a plug-in hybrid electric vehicle (PHEV). [Explanation of symbols]

[0043] 10 Battery Modules 20 battery cells 24 Positive terminal 26 Negative terminal 30 Bus Bar 33 Plate-shaped part (connecting projection) 34. First connection section (connection section) 35. Second connection section (connection section) 37. Nut (fastening part) 40. Bolts for the cover (cover components) 50 Bypass member 51 First through hole (through hole) 52 Second through hole (through hole) 55 volts 58 volts AR band-shaped region (straight line)

Claims

1. Three or more battery cells having positive and negative terminals, Multiple conductive busbars connect the positive terminal of one of two adjacent battery cells to the negative terminal of the other, Equipped with, A battery module in which the busbar is provided with fastening portions for mechanically fastening a bypass member, which is a different material from the busbar and has conductivity.

2. The fastening portion, The busbar has a nut fixed to it, The battery module according to claim 1, wherein the bypass member has a through hole through which a bolt that can be screwed into the nut can pass.

3. The battery module according to claim 1 or claim 2, wherein, in a plan view, the fastening portion is separated from the straight line connecting the connection portion of the busbar to the positive terminal and the connection portion to the negative terminal.

4. The battery module according to claim 1 or claim 2, comprising a cover member that can be attached to the busbar so as to cover the fastening portion and is detachable from the busbar.

5. The battery module according to claim 1 or claim 2, wherein the busbar is provided with a connecting projection that protrudes upward.

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