Battery pack

Abstract

To provide a battery pack 40 that can flexibly respond to changes in specifications.SOLUTION: A battery pack 40 mounted on a hybrid system 10 includes a battery module 50 that supplies power to a motor generator 2 of the hybrid system 10, a control circuit that controls the battery module 50, and a housing 400 that accommodates the battery module 50 and the control circuit. The battery module 50 includes a plurality of battery cells 510 and a cell case 500 that accommodates the plurality of battery cells 510 and has a fixed portion 500a with the housing 400. The control circuit includes a BMU 85 that monitors and controls the overall state of the battery module 50, and a CMU 87 that monitors the state of each of the plurality of battery cells 510 and sends information to the BMU 85. The CMU 87 is attached to the cell case 500 in one battery module 50.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a battery pack installed in a hybrid system. [Background technology]

[0002] Patent Document 1 discloses a battery mounting structure used in electric vehicles and hybrid vehicles. This battery mounting structure includes a case that houses a plurality of battery modules for driving the vehicle on the underside of a floor panel of a vehicle interior. The plurality of battery modules are divided into a lower module and an upper module, and the case has a lower case member made of metal, a middle case member made of metal, and an upper case member for covering a predetermined area of ​​the upper surface of the middle case member from above. The lower module is fixed to the bottom of the lower case member, and the middle case member is fixed to the lower case member so as to cover the lower module from above, so that the lower module is housed watertight. The upper module is fixed in a state in which it is in close contact with the upper surface of the middle case member within a predetermined area. The upper case member is formed in a container shape having an opening at the bottom, and is fixed in a state in which it covers a predetermined area and the periphery of the opening is in close contact with the upper surface of the middle case member, so that the upper module is housed watertight. The lower case member is attached to the underside of the floor panel, so that the case is fixed to the vehicle.

[0003] Patent Document 2 discloses a battery pack device used in, for example, an electric vehicle, which is composed of batteries stacked in multiple stages. The battery pack device includes a first battery group composed of a plurality of batteries arranged on the same plane, and a second battery group composed of a plurality of batteries identical to the first battery group arranged on the same plane in the battery tray, which is stacked on the first battery group with a battery tray in between, and includes a battery pack body including a battery section in which the batteries are electrically connected to each other, and a body case that houses the battery section. The battery is rectangular and can be installed in a first position in which the height in the direction in which the second battery group overlaps with the first battery group is small, and in a second position in which the positions of the terminals of the battery in the overlapping direction are higher than the positions of the terminals in the first position. This battery pack device is characterized in that a first battery of a first battery group is arranged in a second position, a hole is formed in the battery tray through which the vicinity of the terminal of the first battery passes and the terminal of the first battery is exposed to the second battery group side, a second battery of the second battery group near the hole is arranged in the first position, and the first battery and second battery are electrically connected to each other by a connecting member having a fixed shape.

[0004] The battery pack housing contains the number of battery cells required to obtain the desired voltage. The status of each battery cell is monitored by a CMU (Cell Management Unit), and the overall status of the battery module including multiple battery cells is monitored by a BMU (Battery Management Unit). For this reason, the design of the battery pack requires a control circuit that corresponds to the number and layout of battery cells required to obtain the desired voltage specifications, making it difficult to flexibly respond to specification changes. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2020-001451 A [Patent Document 2] JP 2006-080042 A Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention has been made in consideration of the above circumstances, and has an object to provide a battery pack that can flexibly respond to changes in specifications. [Means for solving the problem]

[0007] One aspect of the present invention is a battery pack mounted on a hybrid system, comprising: a battery module that supplies power to a motor generator of the hybrid system; a control circuit that controls the battery module; and a housing that accommodates the battery module and the control circuit, wherein the battery module has a plurality of battery cells and a cell case that accommodates the plurality of battery cells, and the control circuit has a BMU (Battery Management Unit) that monitors and controls the overall state of the battery pack, and a CMU (Cell Management Unit) that monitors the state of each of the plurality of battery cells and sends information to the BMU, and the CMU is a battery pack that is attached to the cell case in the battery module. Effect of the Invention

[0008] According to the present invention, it is possible to provide a battery pack that can flexibly respond to changes in specifications. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a block diagram showing a hybrid system. [Diagram 2] 1 is an external perspective view illustrating a battery pack according to an embodiment of the present invention; [Diagram 3] 1 is a partially exploded perspective view illustrating a battery pack according to an embodiment of the present invention; [Figure 4] FIG. 2 is a partially exploded perspective view illustrating a battery module. [Diagram 5] 1 is a schematic perspective view illustrating a connection of a plurality of battery cells; [Figure 6] 1 is a schematic perspective view illustrating an arrangement of a plurality of battery modules; [Figure 7] FIG. 2 is a plan view illustrating an example of an arrangement of a plurality of battery modules. [Figure 8] FIG. 2 is a plan view illustrating an individual cell casing. [Figure 9] FIG. 1 is a plan view showing an arrangement example (part 1) of individual cell cases. [Figure 10] FIG. 11 is a perspective view showing an arrangement example (part 2) of individual cell cases. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. The embodiments described below are preferred specific examples of the present invention, and therefore various technically preferable limitations are applied to them, but the scope of the present invention is not limited to these aspects unless otherwise specified in the following description to the effect that the present invention is limited to them. In addition, in each drawing, similar components are given the same reference numerals, and detailed descriptions thereof are omitted as appropriate.

[0011] (Hybrid system) FIG. 1 is a block diagram showing a hybrid system. A battery pack 40 to which the housing according to this embodiment is applied is mounted in a hybrid system 10 shown in Fig. 1. The hybrid system 10 includes an engine 1, a motor generator 2, and the battery pack 40. The hybrid system 10 according to this embodiment further includes a DC / DC converter 70. The engine 1 is an internal combustion engine, for example, a diesel engine. The engine 1 is mounted in, for example, a vehicle (such as a passenger car or a small mobile object) or an industrial machine such as a construction machine or an agricultural machine.

[0012] The engine 1 is, for example, a multi-cylinder diesel engine such as a turbocharged high-output three-cylinder or four-cylinder engine. However, the engine 1 is not limited to a diesel engine. The engine 1 has an ECU (Engine Control Unit) 150. The ECU 150 controls the operation of the engine 1 and also controls the motor generator 2 and the DC / DC converter 70 by communicating with them via, for example, a CAN (Controller Area Network).

[0013] The motor generator 2 operates with power supplied from the battery pack 40 to support the engine 1 when power is required, such as when the vehicle in which the hybrid system 10 is mounted starts or accelerates. The motor generator 2 also uses regenerative braking or the like to convert the kinetic energy of the industrial machinery in which the hybrid system 10 is mounted into electrical energy to generate electricity.

[0014] The battery pack 40 includes a battery module 50, a positive contactor 75, a negative contactor 76, a current value detector 65, a temperature detector 67, a BMU (Battery Management Unit) 85, and a CMU (Cell Management Unit) 87. The battery module 50 is provided as a driving power source for the motor generator 2, and supplies power to the motor generator 2. The battery module 50 includes at least one battery cell 510. In the hybrid system 10 shown in FIG. 1, the battery module 50 includes a number of battery cells 510 required to obtain a voltage of, for example, 48V. An example of the battery cell 510 is a lithium ion battery (LiB). However, the battery cell 510 of this embodiment is not limited to a lithium ion battery. The battery module 50 includes a positive (+) terminal 51 and a negative (-) terminal 52.

[0015] The positive electrode side contactor 75 is provided in an electric circuit between the positive electrode terminal 51 of the battery module 50 and the motor generator 2. Specifically, as shown in Fig. 1, the positive electrode side contactor 75 is provided in positive electrode wirings 173, 174 that connect the positive electrode terminal 51 of the battery module 50 and the motor generator 2. In other words, the electric circuit between the positive electrode terminal 51 of the battery module 50 and the motor generator 2 includes the positive electrode wiring 173 and the positive electrode wiring 174. The positive electrode side contactor 75 is electrically connected to the ECU 150 by a signal line 181, and opens and closes the positive electrode wirings 173, 174 based on a control signal transmitted from the ECU 150 through the signal line 181.

[0016] The positive contactor 75 may be electrically connected to the BMU 85. In this case, the positive contactor 75 opens and closes the positive wirings 173, 174 based on a control signal transmitted from the BMU 85. In the description of the present embodiment, a case in which the positive contactor 75 is electrically connected to the ECU 150 by a signal line 181 will be taken as an example.

[0017] The negative contactor 76 is provided in an electric circuit between the negative terminal 52 of the battery module 50 and the motor generator 2. Specifically, as shown in Fig. 1, the negative contactor 76 is provided in a negative wiring 175 that connects the negative terminal 52 of the battery module 50 and the motor generator 2. In other words, the electric circuit between the negative terminal 52 of the battery module 50 and the motor generator 2 includes the negative wiring 175. The negative contactor 76 is electrically connected to the BMU 85 by a signal line 182, and opens and closes the negative wiring 175 based on a control signal transmitted from the BMU 85 through the signal line 182.

[0018] The negative contactor 76 may be electrically connected to the ECU 150. In this case, the negative contactor 76 opens and closes the negative wiring 175 based on a control signal transmitted from the ECU 150. In the description of the present embodiment, a case in which the negative contactor 76 is electrically connected to the BMU 85 by a signal line 182 will be taken as an example.

[0019] The BMU 85 is an example of a "control circuit" of the present invention. The BMU 85 controls the overall voltage of the battery module 50. That is, the BMU 85 is electrically connected to the ECU 150 by a signal line 193, and controls the negative contactor 76 based on a control signal transmitted from the ECU 150 through the signal line 193. The ECU 150 and the BMU 85 communicate with each other, for example, by a CAN, and monitor each other's states.

[0020] The BMU 85 also monitors the state of the battery module 50 and can detect an abnormality in the battery module 50. For example, the BMU 85 detects an overcharge (minor failure) abnormality or an overcharge (major failure) abnormality based on the voltage of the battery cell 510 acquired from the CMU 87. Alternatively, the BMU 85 detects an overdischarge (minor failure) abnormality or an overdischarge (major failure) abnormality based on the voltage of the battery cell 510 acquired from the CMU 87. Alternatively, the BMU 85 detects an overtemperature (minor failure) abnormality based on the temperature of the battery cell 510 acquired from the CMU 87. Alternatively, the BMU 85 detects an overcurrent abnormality based on a current value acquired from a current value detection unit 65 provided in the positive electrode wiring 174.

[0021] The CMU 87 is an example of a "control circuit" of the present invention. The CMU 87 monitors the state of the battery cells 510 included in the battery module 50 and sends the information to the BMU 85. When the battery module 50 includes a plurality of battery cells 510, the CMU 87 monitors the voltage of each battery cell 510 and sends information about the voltage of each battery cell 510 to the BMU 85 through a signal line 191. The CMU 87 also obtains information about the temperature of the battery cells 510 detected by the temperature detection unit 67 from a signal line 183, and sends the information about the temperature of the battery cells 510 to the BMU 85 through the signal line 191. The CMU 87 is provided separately from the BMU 85.

[0022] As described above, the negative electrode wiring 175 electrically connects the negative electrode terminal 52 of the battery module 50 to the motor generator 2, and serves as the ground 100B. For example, the negative electrode wiring 175 is connected to the body of a vehicle or the like in which the hybrid system 10 is mounted, and is grounded. The positive electrode wiring 173 electrically connects the positive electrode terminal 51 of the battery module 50 to the motor generator 2, and also electrically connects the motor generator 2 to the DC / DC converter 70. When the battery module 50 is a 48V lithium-ion battery as in the hybrid system 10 shown in FIG. 1, the potential of the positive electrode wirings 173, 174 relative to the negative electrode wiring 175 is 48V.

[0023] The DC / DC converter 70 is electrically connected to the battery 80 via a positive wiring 171 and a negative wiring 172. An example of the battery 80 is a 12V lead-acid battery. The negative wiring 172 electrically connects the negative terminal 82 of the battery 80 to the DC / DC converter 70, and serves as a ground 100B. For example, the negative wiring 172 is connected to the body of a vehicle or the like in which the hybrid system 10 is mounted and is grounded. The positive wiring 171 electrically connects the positive terminal 81 of the battery 80 to the DC / DC converter 70. When the battery 80 is a 12V lead-acid battery as in the hybrid system 10 shown in FIG. 1, the potential of the positive wiring 171 relative to the negative wiring 172 is 12V.

[0024] As described above, the motor generator 2 uses regenerative braking or the like to convert the kinetic energy of the vehicle or the like in which the hybrid system 10 is mounted into electrical energy to generate electricity. The motor generator 2 supplies a voltage to the battery module 50 to charge the battery module 50, and also supplies a voltage to the battery 80 to charge the battery 80. Here, taking the hybrid system 10 shown in FIG. 1 as an example, the potential of the positive electrode wiring 173 relative to the negative electrode wiring 175 is 48V. That is, the generated voltage of the motor generator 2 is 48V. On the other hand, the potential of the positive electrode wiring 171 relative to the negative electrode wiring 172 is 12V. Therefore, the DC / DC converter 70 converts the voltage of 48V generated by the motor generator 2 into a voltage of 12V. As a result, the motor generator 2 can supply a voltage of 12V to the battery 80 via the DC / DC converter 70 to charge the battery 80.

[0025] Furthermore, the DC / DC converter 70 is electrically connected to the battery module 50 and the battery 80, and can perform charging and discharging between the battery module 50 and the battery 80 based on a control signal transmitted from the ECU 150. For example, the DC / DC converter 70 can discharge the battery module 50 and charge the battery 80 by converting the voltage and causing a constant current (e.g., 10 A) to flow from the battery module 50 to the battery 80. Alternatively, for example, the DC / DC converter 70 can discharge the battery 80 and charge the battery module 50 by converting the voltage and causing a constant current (e.g., 10 A) to flow from the battery 80 to the battery module 50.

[0026] The hybrid system 10 of this embodiment has the function of safely cutting off the electrical circuit that supplies power from the battery module 50 to the motor generator 2 when an abnormality occurs in the battery module 50 or when the entire hybrid system 10 is shut down.

[0027] For example, when the ignition switch is turned on, the ECU 150 transmits a control signal to the positive contactor 75 through a signal line 181 and executes control to close the positive contactor 75, thereby electrically connecting the positive wiring 174. The BMU 85 also executes control to close the negative contactor 76 based on a control signal transmitted from the ECU 150 through a signal line 193, thereby electrically connecting the negative wiring 175. This enables the battery module 50 to supply power to the motor generator 2.

[0028] On the other hand, for example, when the ignition switch is turned off, the ECU 150 transmits a control signal to the positive contactor 75 through a signal line 181 and executes control to open the positive contactor 75, thereby electrically cutting off the positive wiring 174. Also, the BMU 85 executes control to open the negative contactor 76 based on a control signal transmitted from the ECU 150 through a signal line 193, thereby electrically cutting off the negative wiring 175. As a result, the supply of power from the battery module 50 to the motor generator 2 is stopped.

[0029] Furthermore, when the BMU 85 detects, for example, an abnormality in the battery module 50, the ECU 150 transmits a first interruption signal R1 to the positive contactor 75 via a signal line 181 and executes control to open the positive contactor 75, thereby electrically interrupting the positive wiring 174. Furthermore, the BMU 85 transmits a second interruption signal R2 to the negative contactor 76 via a signal line 182 independently of a control signal transmitted from the ECU 150 and executes control to open the negative contactor 76, thereby electrically interrupting the negative wiring 175.

[0030] Alternatively, as described above, the ECU 150 and the BMU 85 communicate with each other and monitor each other's states. When the ECU 150 detects an abnormality in the BMU 85, the ECU 150 transmits a first interruption signal R1 to the positive contactor 75 via a signal line 181 and executes control to open the positive contactor 75, thereby electrically interrupting the positive wiring 174. On the other hand, when the BMU 85 detects an abnormality in the ECU 150, the BMU 85 transmits a second interruption signal R2 to the negative contactor 76 via a signal line 182 independently of a control signal transmitted from the ECU 150 and executes control to open the negative contactor 76, thereby electrically interrupting the negative wiring 175.

[0031] According to the hybrid system 10 described above, two contactors (in this embodiment, the positive electrode contactor 75 and the negative electrode contactor 76) are provided in an electric circuit (in this embodiment, the positive electrode wirings 173, 174 and the negative electrode wiring 175) that supplies electric power from the battery module 50 to the motor generator 2, and the ECU 150 controls the positive electrode contactor 75, and the BMU 85 controls the negative electrode contactor 76. Therefore, even if an abnormality occurs in the battery module 50 or in either the ECU 150 or the BMU 85, the hybrid system 10 according to this embodiment can cut off the electric circuit that supplies electric power from the battery module 50 to the motor generator 2. As a result, the hybrid system 10 can improve the safety of the battery module 50 that supplies electric power to the motor generator 2.

[0032] (Battery pack) FIG. 2 is an external perspective view illustrating the battery pack according to the present embodiment. FIG. 3 is a partially exploded perspective view illustrating the battery pack according to the present embodiment. FIG. 3 shows a state in which a housing cover 420 of a housing 400 of the battery pack 40 is open. The battery pack 40 includes a battery module 50, a control circuit including a BMU 85 and a CMU 87, and a housing 400 that houses the battery module 50 and the control circuit. The housing body 410 and the housing cover 420 are formed by casting using a metal material including aluminum, for example. A seal (not shown) is provided at the joint between the housing body 410 and the housing cover 420, and the inside of the housing 400 becomes watertight by covering the housing body 410 with the housing cover 420 and fastening and fixing them, for example, with screws.

[0033] The battery module 50 accommodated in the housing 400 has a plurality of battery cells 510. The plurality of battery cells 510 are accommodated in a cell case 500. The cell case 500 has a fixing portion 500a for fixing the cell case 500 to the housing 400 in a state in which the plurality of battery cells 510 are accommodated therein. One battery module 50 may be accommodated in one housing 400, or a plurality of battery modules 50 may be accommodated therein.

[0034] 2 and 3, two battery modules 50 are accommodated in one housing 400. For example, when configuring a 48V battery pack 40, in this embodiment, two 24V battery modules 50 are accommodated in the housing 400 and connected in series. Nine battery cells 510 are accommodated in the cell case 500 in one battery module 50.

[0035] In this embodiment, a CMU 87 is attached to the cell case 500 in one battery module 50. That is, the CMU 87, which monitors the state of each of the multiple battery cells 510 housed in the cell case 500, is attached to the cell case 500 that houses the battery cell 510.

[0036] 3, in one battery pack 40, when, for example, two battery modules 50 are accommodated in the housing 400, a configuration is adopted in which one BMU 85 is shared. That is, one BMU 85 is provided in the housing 400, and this BMU 85 performs control to monitor the entirety of a plurality (for example, two) battery modules 50. Since a CMU 87 that monitors a plurality of battery cells 510 in each battery module 50 is provided in the cell case 500 in each battery module 50, even when the number of battery modules 50 accommodated in the battery pack 40 is changed, it is only necessary to change the arrangement of the battery modules 50 without changing the BMU 85.

[0037] For example, in the case of the battery pack 40 according to this embodiment, the housing 400 houses two battery modules 50 for a 48V specification, but when these are combined into one to change to a 24V specification, this can be achieved by removing one of the two battery modules 50 from the housing 400. Also, when three battery modules 50 are housed in one housing 400 for a 72V specification, this can be achieved without making a major design change to the BMU 85 by changing the size of the housing 400 so that it can house three battery modules 50.

[0038] (Battery module) FIG. 4 is a partially exploded perspective view illustrating an example of a battery module. Figure 4 shows one battery cell removed from the cell case. The cell case 500 is formed of, for example, resin. The cell case 500 has an accommodation portion 501 that accommodates the battery cells 510, and a mounting portion 502 on which the CMU 87 is placed. The accommodation portion 501 is provided in a box shape that can accommodate multiple battery cells 510, and the mounting portion 502 is provided in a flat shape so that the substrate of the CMU 87 can be easily placed. In this embodiment, the multiple battery cells 510 are arranged side by side and stacked in the accommodation portion 501.

[0039] The battery cell 510 is provided in a substantially rectangular parallelepiped shape having a plane portion 510a and a bottom portion 510b facing each other, and four side portions 510c each having an area smaller than that of the plane portion 510a and the bottom portion 510b. The battery cells 510 are arranged side by side along the bottom surface 400a (see FIG. 3) of the housing 400 so that the bottom portion 510b faces the bottom surface 400a of the housing 400. Specifically, the battery cells 510 are arranged so that the bottom portion 510b faces the mounting surface 501a, which is the inner bottom of the storage portion 501 of the cell case 500. When the cell case 500 is stored in the housing 400, the mounting surface 501a of the storage portion 501 is substantially parallel to the bottom surface 400a of the housing 400. Therefore, the bottom portion 510b of the battery cell 510 is arranged to face the bottom surface 400a of the housing 400. By placing each of the plurality of battery cells 510 with the bottom surface portion 510b facing the placement surface 501a, the battery module 50 can be made thinner.

[0040] 4, battery cells 510 are housed in a state of being stacked in two stages in the housing portion 501 of the cell case 500. Five battery cells 510 are arranged side by side in the first stage, and four battery cells 510 are arranged side by side in the second stage. At the very end, there is only one stage of battery cells 510, and a mounting portion 502 for mounting a CMU 87 is provided in the space above that, which constitutes the second stage.

[0041] FIG. 5 is a perspective view illustrating the connection of a plurality of battery cells. Fig. 5 shows a perspective view of a plurality of battery cells 510 in Fig. 4 as viewed from the opposite side to that in Fig. 4. For convenience of explanation, the cell case 500 and the CMU 87 are omitted in Fig. 5. For the cell case 500 and the CMU 87, refer to Fig. 4. When an odd number (n) of battery cells 510 are accommodated in one cell case 500, it is preferable for one cell case 500 to accommodate a first stage cell group CG1 in which {(n+1) / 2} battery cells 510 are juxtaposed in a direction along the bottom surface 400a of the housing 400 (see FIG. 3) (hereinafter also simply referred to as the "first direction D1"), and a second stage cell group CG2 in which {(n-1) / 2} battery cells 510 are juxtaposed in the first direction D1 and stacked with the first stage cell group CG1 in the normal direction of the bottom surface 400a of the housing 400 (hereinafter also simply referred to as the "normal direction D3").

[0042] 5, when nine battery cells 510 are accommodated in one cell case 500, the battery cells are stacked in two tiers, with the first tier being a first-tier cell group CG1 and the second tier being a second-tier cell group CG2. In the first-tier cell group CG1, five battery cells 510 are arranged in the first direction D1, and in the second-tier cell group CG2, four battery cells 510 are arranged in the first direction D1. The nine battery cells 510 arranged in this manner are accommodated in the accommodation portion 501 of the cell case 500.

[0043] The CMU 87 is disposed on the side of the second-stage cell group CG2 of the first-stage cell group CG1, and aligned with the second-stage cell group CG2 in the first direction D1. For example, in the case of nine battery cells 510, five battery cells 510 are arranged side by side as the first-stage cell group CG1, and four battery cells 510 are arranged side by side as the second-stage cell group CG2, and these are stacked in the normal direction D3. Therefore, a vacant space for one cell is formed in the arrangement of the second-stage cell group CG2. This vacant space is used as the mounting portion 502 shown in FIG. 4, and the CMU 87 is disposed therein. This allows the space of the battery module 50 to be effectively utilized. In the present embodiment, an example in which an odd number of battery cells 510 are provided in one battery module 50 has been shown, but an even number of battery cells 510 may be provided.

[0044] As shown in FIG. 5, a positive electrode +, a negative electrode -, and a valve V (cell valve) for releasing gas are provided on one of the side portions 510c of the rectangular parallelepiped battery cell 510. When placing and stacking a plurality of battery cells 510, the side portions 510c on which the positive electrode + and the negative electrode - are provided are made to face the same side. In this case, the arrangement of the positive electrode + and the negative electrode - of the battery cells 510 is reversed between the first cell group CG1 and the second cell group CG2. That is, in the first cell group CG1, the battery cells 510 are arranged so that the electrodes of the plurality of battery cells 510 are arranged in the order of positive electrode +, negative electrode -, positive electrode +, negative electrode -, ... from one end to the other end in the first direction, and in the second cell group CG2, the battery cells 510 are arranged in the opposite order of negative electrode -, positive electrode +, negative electrode -, positive electrode +, ....

[0045] The battery cells 510 constituting the first-stage cell group CG1 are conductively connected by the first connecting bus bar B1 in the order of arrangement from one end to the other end in the first direction D1. The battery cells 510 constituting the second-stage cell group CG2 are conductively connected by the second connecting bus bar B2 in the order of arrangement from one end to the other end in the first direction D1. The battery cell 510 arranged at the other end of the first-stage cell group CG1 and the battery cell 510 arranged at the other end of the second-stage cell group CG2 are conductively connected by the third connecting bus bar B3. Here, the bus bar is a metal (e.g., copper) plate material formed into a predetermined shape. In this embodiment, a bus bar is used as a member for conductively connecting adjacent battery cells 510, but a conductor other than a bus bar may be used. In the battery cells 510 arranged at the other end of each of the first stage cell group CG1 and the second stage cell group CG2 (two battery cells 510 stacked at the other end), the electrode polarities are aligned as positive + and negative - in the stacking direction, so that by simply attaching the third connecting busbar B3 straight in the stacking direction, the multiple battery cells 510 of the first stage cell group CG1 and the second stage cell group CG2 are connected in series.

[0046] FIG. 6 is a perspective view illustrating an arrangement of a plurality of battery modules. FIG. 7 is a plan view illustrating an example of an arrangement of a plurality of battery modules. 6 and 7 show an example in which two battery modules 50 shown in Fig. 5 are arranged. For convenience of explanation, the cell case 500 and the CMU 87 are omitted in Fig. 6. For the cell case 500 and the CMU 87, refer to Fig. 4. When arranging the multiple battery modules 50, it is preferable to juxtapose the multiple battery modules 50 in a second direction (hereinafter, also simply referred to as "second direction D2") that intersects with the first direction D1 along the bottom surface 400a (see FIG. 2) of the housing 400 (see FIG. 2). In this arrangement of the multiple battery modules 50, the battery cells 510 are arranged such that the positive pole +, negative pole -, and valve V face each other between adjacent battery modules 50.

[0047] As a result, the first connecting bus bar B1, the second connecting bus bar B2, and the third connecting bus bar B3 in each battery module 50 are arranged to face each other between adjacent battery modules 50. By having the first connecting bus bar B1, the second connecting bus bar B2, and the third connecting bus bar B3 in each battery module 50 facing each other, it becomes easier to unify the conduction paths in the multiple battery modules 50, and the space required for the battery pack 40 can be saved.

[0048] Furthermore, the battery modules 50 adjacent to each other in the second direction D2 are conductively connected to each other at one end in the first direction D1 by the fourth connecting bus bar B4. In this case, it is preferable that the two battery cells 510 connected by the fourth connecting bus bar B4 are arranged in the same stage. This allows the fourth connecting bus bar B4 to be attached in the same stage.

[0049] In order to arrange two battery cells 510 connected by the fourth connecting bus bar B4 in the same stage when adjacent battery modules 50 are connected in series, the arrangement of the positive poles + and negative poles - of two battery cells 510 facing each other (two battery cells 510 facing each other in the second direction D2 between adjacent battery modules 50) may be reversed in the plurality of battery cells 510 of adjacent battery modules 50. This causes the positive poles + and negative poles - of the two battery cells 510 connecting the fourth connecting bus bar B4 to face each other, and the connection of the positive poles + and negative poles - at the fourth connecting bus bar B4 can be made over the shortest distance.

[0050] For example, the battery module 50 on one side of two adjacent battery modules 50 is connected in sequence by a first connecting bus bar B1 from the battery cell 510 at one end of the first stage cell group CG1 in the first direction D1 to the battery cell 510 at the other end, the battery cell 510 of the first stage cell group CG1 located at the other end and the battery cell 510 of the second stage cell group CG2 are connected by a third connecting bus bar B3, and the battery cell 510 at the other end of the second stage cell group CG2 in the first direction are connected in sequence by a second connecting bus bar B2 from the battery cell 510 at the other end of the second stage cell group CG2 in the first direction to the battery cell 510 at one end.

[0051] On the other hand, the battery module 50 on the other side of two adjacent battery modules 50 is connected in the opposite manner to the battery module 50 on one side, from the battery cells 510 at one end of the second stage cell group CG2 in the first direction D1 to the battery cells 510 at the other end by the second connecting bus bar B2, the battery cells 510 of the second stage cell group CG2 located at the other end and the battery cells 510 of the first stage cell group CG1 are connected by a third connecting bus bar B3, and the battery cells 510 at the other end of the first stage cell group CG1 in the first direction are connected by the first connecting bus bar B1.

[0052] In two adjacent battery modules 50, the battery cells 510 at one end in the first direction D1 of the respective second stage cell groups CG2 are connected to each other by the fourth coupling bus bar B4.

[0053] In other words, the connection configuration from the first connecting bus bar B1 to the fourth connecting bus bar B4 is a connection configuration in which the first stage cell group CG1 on one side of two adjacent battery modules 50 is connected from one end to the other end, the other end is connected to the second stage cell group CG2 and returns to one end, the other end of the second stage cell group CG2 is connected to the battery module 50 on the other side, the second stage cell group CG2 is connected from one end to the other end, and the other end is connected to the first stage cell group CG1 and returns to one side. This connection configuration allows connection via the shortest route.

[0054] Furthermore, the battery module 50 is provided with wiring (not shown) for sending information indicating the state (voltage and temperature) of the battery cells 510 to the CMU 87. When multiple battery modules 50 are arranged, the wiring is arranged so as to be sent to the CMU 87 between adjacent battery modules 50. This makes it possible to effectively use the space between adjacent battery modules 50 and send the wiring together to the CMU 87.

[0055] In addition, by arranging the valves V of each battery cell 510 in each battery module 50 so as to face each other between adjacent battery modules 50, the space between adjacent battery modules 50 can be used as a flow path for gas released from the valves.

[0056] 3, when the housing cover 420 is provided with a vent valve 425 that opens when the internal pressure of the housing 400 reaches a predetermined pressure, it is preferable to place the vent valve 425 at a position that overlaps with the space between adjacent battery modules 50 when viewed in the normal direction (see the figure). This allows gas released from the valve to be efficiently exhausted from the vent valve 425 using the space between adjacent battery modules 50 as a flow path.

[0057] In the above, an example has been shown in which five battery cells 510 are juxtaposed in the first-stage cell group CG1, and four battery cells 510, one less than the first-stage cell group CG1, are juxtaposed in the second-stage cell group CG2, but the present invention is not limited to this. The number of battery cells 510 in the second-stage cell group CG2 may be two or more less than the first-stage cell group CG1, the juxtaposition of the multiple battery cells 510 in the second-stage cell group CG1 may be discontinuous, and the position of the mounting portion 502 (see FIG. 4) may not be the end of the second-stage cell group CG2.

[0058] (Individual cell case) FIG. 8 is a plan view illustrating an individual cell casing. The individual cell case 550 is a case that houses one battery cell 510. The individual cell case 550 includes an individual cell case main body 551 that houses one battery cell 510, and a connecting portion 552 provided on the periphery of the individual cell case main body 551. The individual cell case main body 551 is provided in a box shape that houses one battery cell 510 inside. The individual cell case main body 551 has a substantially rectangular (for example, a square) outer shape in a plan view. The connecting portion 552 is provided at each corner of the individual cell case main body 551. The connecting portion 552 may be provided at the center of each side of the individual cell case main body 551. The connecting portion 552 may be provided with a hole for bolt fastening, or may be provided with an engagement portion that is fitted into a recess or projection.

[0059] FIG. 9 is a plan view showing an arrangement example (part 1) of the individual cell cases. In the example shown in FIG. 9, a configuration is provided in which a plurality of individual cell cases 550 are connected vertically and horizontally along a plane. A single cell case 500 is formed by connecting a plurality of individual cell cases 550. Adjacent individual cell cases 550 in both the vertical and horizontal directions are connected to each other using their connecting portions 552. A plurality of individual cell cases 550 may be connected vertically and horizontally along the same plane, or a plurality of individual cell cases 550 may be connected in one direction, vertically or horizontally, on the same plane. Also, a plurality of individual cell cases 550 connected on the same plane may be stacked to form a multi-stage configuration.

[0060] FIG. 10 is a perspective view showing an arrangement example (part 2) of the individual cell cases. 10, a configuration in which a plurality of individual cell cases 550 are stacked and connected. A single cell case 500 is formed by connecting a plurality of individual cell cases 550. The individual cell cases 550 adjacent to each other in the stacking direction are connected to each other using their connecting portions 552. Fastening may be performed with bolts that penetrate the connecting portions 552 of all the individual cell cases 550 that are stacked together.

[0061] In connecting multiple individual cell cases 550 as shown in Figures 9 and 10, the positive electrode + or negative electrode - of the battery cell 510 may be electrically connected to the connecting portion 552, and adjacent (or overlapping) individual cell cases 550 may be connected to each other via the connecting portion 552, thereby making it possible to electrically connect the battery cells 510 of the multiple individual cell cases 550 in series or parallel.

[0062] According to this embodiment, it is possible to provide a battery pack 40 that can flexibly respond to changes in specifications.

[0063] The above describes the embodiments of the present invention. However, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the claims. For example, the configurations of the above embodiments can be partially omitted or arbitrarily combined in a manner different from the above. [Explanation of symbols]

[0064] 1 ... engine, 2 ... motor generator, 10 ... hybrid system, 40 ... battery pack, 50 ... battery module, 51 ... positive terminal, 52 ... negative terminal, 65 ... current value detection unit, 67 ... temperature detection unit, 70 ... DC / DC converter, 75 ... positive electrode contactor, 76 ... negative electrode contactor, 80 ... battery, 81 ... positive electrode terminal, 82 ... negative electrode terminal, 85 ... BMU, 87 ... CMU, 100B ... ground, 150 ... ECU, 171 ... positive electrode wiring, 172 ... negative electrode wiring, 173 ... positive electrode wiring, 174 ... positive electrode wiring, 175 ... negative electrode wiring, 181 ... signal line, 182 ... signal line, 183 ... signal line, 191 ... signal line, 193 ... signal line, 400 ... housing, 400a...bottom surface, 410...housing main body, 420...housing cover, 425...vent valve, 500...cell case, 500a...fixing portion, 501...accommodating portion, 501a...mounting surface, 502...mounting portion, 510...battery cell, 510a...flat portion, 510b...bottom portion, 510c...side portion, 550...individual cell case, 551...individual cell case main body, 552...connecting portion, B1...first connecting bus bar, B2...second connecting bus bar, B3...third connecting bus bar, B4...fourth connecting bus bar, CG1...first stage cell group, CG2...second stage cell group, D1...first direction, D2...second direction, D3...normal direction, R1...first shutoff signal, R2...second shutoff signal, V...valve

Claims

1. A battery pack mounted in a hybrid system, a battery module for supplying power to a motor generator of the hybrid system; A control circuit for controlling the battery module; a housing that accommodates the battery module and the control circuit; Equipped with The battery module includes: A plurality of battery cells; a cell case that houses the plurality of battery cells; The control circuit includes: A Battery Management Unit (BMU) that monitors and controls the overall state of the battery pack; A CMU (Cell Management Unit) that monitors the state of each of the plurality of battery cells and sends the information to the BMU, The CMU is attached to the cell casing in the battery module.

2. The battery pack according to claim 1 , wherein the cell case has a cell case body and a plurality of housing portions provided in the cell case body and housing each of the plurality of battery cells.

3. The battery pack of claim 1 , wherein the cell casing comprises a plurality of individual casings housing respective ones of the plurality of battery cells.

4. The battery pack according to claim 1 , wherein the plurality of battery cells are arranged side by side along a bottom surface of the housing and stacked in a normal direction to the bottom surface.

5. The battery pack of claim 1 , wherein all of the plurality of battery cells are arranged side-by-side along a bottom surface of the housing.

6. Each of the plurality of battery cells is provided in a substantially rectangular parallelepiped shape having a planar portion and a bottom portion facing each other, and four side portions each having an area smaller than that of the planar portion and the bottom portion; The battery pack according to claim 1 , wherein the plurality of battery cells are arranged side by side along the bottom surface of the housing such that the bottom surface portions face the bottom surface of the housing.

7. The battery module includes n battery cells (n is an odd number), The cell casing comprises: a first stage cell group in which {(n+1) / 2} battery cells are arranged in a first direction along a bottom surface of the housing; a second-stage cell group in which {(n-1) / 2} battery cells are arranged side by side in the first direction and stacked on the first-stage cell group in a normal direction to the bottom surface; 2 . The battery pack according to claim 1 , wherein the CMU is disposed on a side of the first stage cell group toward the second stage cell group, and aligned with the second stage cell group in the first direction.

8. A battery module according to the present invention includes: The battery pack according to claim 7 , wherein the plurality of battery modules are arranged side by side with one another along the bottom surface in a second direction intersecting the first direction.

9. The battery cell has a cell valve that opens when pressure in the cell exceeds a predetermined value; The battery pack according to claim 8 , wherein the cell valves of the battery cells facing each other between adjacent battery modules among the plurality of battery modules are arranged to face each other.

10. a vent valve provided in the housing and opened when the internal pressure of the housing reaches a predetermined pressure; The battery pack according to claim 9 , wherein the vent valve is disposed at a position overlapping a gap between adjacent battery modules among the plurality of battery modules when viewed in the normal direction.

11. The battery cell has positive and negative electrode terminals, The battery pack according to claim 8 , wherein the electrode terminals of the battery cells facing each other between adjacent battery modules among the plurality of battery modules are arranged to face each other.

12. The battery pack according to claim 11 , wherein wiring is arranged between adjacent battery modules among the plurality of battery modules, for transmitting information indicating a state of each of the plurality of battery cells to the CMU.

13. The plurality of battery cells constituting the first stage cell group are conductively connected by a first connecting bus bar in an arranged order from one end to the other end in the first direction, the plurality of battery cells constituting the second stage cell group are conductively connected by a second connecting bus bar in an arranged order from the one end to the other end in the first direction, 8. The battery pack according to claim 7, wherein the battery cell arranged at the other end of the first stage cell group and the battery cell arranged at the other end of the second stage cell group are conductively connected by a third connecting bus bar.

14. A battery module according to the present invention includes: The plurality of battery modules are arranged side by side in a second direction intersecting the first direction along the bottom surface, The battery pack according to claim 13 , wherein the battery modules adjacent to each other in the second direction are conductively connected to each other at the one ends by a fourth connecting bus bar.

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