Battery pack

Abstract

The signal terminals of the current sensor are fixed in place without any misalignment, ensuring stable electrical connection of the signal terminals over a long period of time. [Solution] The battery pack comprises a battery block 3A in which a plurality of battery cells 1 are arranged in fixed positions, and an electrical block 3B in which electrical components that control the charging and discharging current of the battery block 3A are installed. The electrical block 3B comprises an output terminal 11, a busbar 20 of a power line 10 that electrically connects the output terminal 11 and the battery block 3A, and a current sensor 30 that detects the current of the busbar 20. The busbar 20 comprises a first busbar 21 of a metal plate connected to the output terminal 11, a second busbar 22 of a metal plate connected to the battery block 3A, and a metal cylinder 31 connecting the first busbar 21 and the second busbar 22. The current sensor 30 is a sensor that detects the current of the metal cylinder 31. The electrical block 3B comprises a sensor housing section 44 that houses the current sensor 30 and a busbar guide section 43 that positions the second busbar 22 in fixed positions.

Description

Technical Field

[0001] The present invention relates to a battery pack including a current sensor.

Background Art

[0002] A high-output battery pack in which a large number of secondary batteries are connected in series and / or in parallel can be conveniently used as a power source for electric vehicles and mobile devices with a large load current. Such a battery pack can increase the output voltage by increasing the number of battery cells connected in series, and can increase the battery capacity by increasing the number of battery cells connected in parallel. In particular, in view of the recent demand for higher output, the number of battery cells used in the battery pack tends to increase. A battery pack that is charged and discharged with a large current needs to accurately detect the current and control the charging and discharging in order to ensure safety, be used stably over a long period of time, and further extend the substantially usable life. Overcharging of the battery pack is a factor that inhibits safety, and overcharging and over-discharging are causes that reduce the electrical characteristics and shorten the life. In order to prevent overcharging and over-discharging of the battery, the battery pack needs to integrate the current, accurately calculate the remaining capacity (SOC), and charge and discharge while maintaining the remaining capacity within a set range. Since the remaining capacity is calculated by integrating the detected current, if there is an error in the detected current, this error accumulates over time and gradually expands. Therefore, for the battery pack, how accurately the current of the battery can be detected over a long period of time is extremely important for both safety and life.

[0003] Patent Document 1 discloses a structure for stably detecting current by increasing the reliability of the soldered joints of the lead terminals of a current sensor 930. This current sensor 930 is a sensor that detects the current of a hollow conductor 931. As shown in Figure 12, the hollow conductor 931 is sandwiched above and below by a bus bar 920 and a power module 903 using bolts 941, and the case of the current sensor 930 is connected to the power module 903 via the hollow conductor 931. This current sensor 930 is a magnetic current sensor that detects the current of the hollow conductor 931 by placing a core on the outside of the hollow conductor 931 through which the current flows and inducing the magnetic flux generated by the current flowing through the bus bar 920 into the windings of the core. The case of the magnetic current sensor has a through hole on the inside of the core through which the hollow conductor 931 is placed. The hollow conductor 931 is inserted into a through-hole in the case, but a gap is provided between the hollow conductor 931 and the through-hole to eliminate stress concentration at the soldering point, thereby improving reliability. However, this fixed-structure current sensor 930 has the problem of not being able to accurately detect current while maintaining high reliability over a long period of time in operating environments subject to vibration and shock. This is because the structure that does not allow the current sensor 930 to be fixed in a fixed position can cause poor contact between the lead wires and busbars 920 in operating environments subject to vibration and shock. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-160034 [Overview of the project] [Problems that the invention aims to solve]

[0005] The current sensor 930 described in Patent Document 1 cannot be securely fixed in a fixed position without displacement, which can cause poor contact with the connected busbar 920, wire harness, or connector. This presents a problem in that it cannot accurately detect current while maintaining high reliability over a long period of time in environments subject to vibration and shock.

[0006] This disclosure was developed with the aim of further eliminating the above-mentioned shortcomings, and one of the objectives of this disclosure is to provide a battery pack that can accurately detect current while maintaining high reliability over a long period of time, even in operating environments subject to vibration and shock, by installing the current sensor in a fixed position without displacement. Furthermore, the description of the purpose and issues in this disclosure does not preclude the existence of other purposes or issues. Also, the nature of this disclosure does not need to solve all of these issues. Moreover, it is possible to extract other issues from the description, drawings, and claims of this disclosure. [Means for solving the problem]

[0007] A battery pack according to one embodiment of the present disclosure comprises a battery block having a plurality of battery cells arranged in fixed positions, and an electrical block having electrical components installed to control the charging and discharging current of the battery block, wherein the battery pack comprises an output terminal installed on the electrical block, a busbar of a power line electrically connecting the output terminal and the battery block, and a current sensor for detecting the current of the busbar, the busbar comprises a first busbar of a metal plate connected to the output terminal, a second busbar of a metal plate connected to the battery block, and a metal cylinder connecting the first busbar and the second busbar, the current sensor is a sensor for detecting the current of the metal cylinder, the electrical block comprises a sensor housing for housing the current sensor and a busbar guide section having the second busbar arranged in fixed positions, and the current sensor, the first busbar and the second busbar are installed on the electrical block. [Effects of the Invention]

[0008] The battery packs described above feature the ability to accurately detect current while maintaining high reliability over long periods, even in environments subject to vibration and shock, by positioning the current sensor in a fixed location without misalignment. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic perspective view showing a battery pack according to one embodiment. [Figure 2] Figure 1 is a schematic exploded perspective view of the battery pack. [Figure 3] Figure 1 is a more detailed schematic exploded perspective view of the battery pack. [Figure 4] Figure 2 is a schematic enlarged perspective view of the electrical block. [Figure 5] Figure 4 is a schematic exploded perspective view of the electrical block. [Figure 6] Figure 5 is a schematic exploded perspective view showing an example of the sensor case and signal terminals of a battery sensor. [Figure 7] Figure 4 is a schematic plan view of the electrical block. [Figure 8] Figure 7 is a schematic cross-sectional perspective view along the line VIII-VIII. [Figure 9] Figure 7 is a schematic cross-sectional view of the IX-IX line. [Figure 10] This is a schematic cross-sectional view showing a portion of a battery pack according to another embodiment. [Figure 11] This is a block diagram showing an example of a current sensor using a metal cylinder as a shunt resistor. [Figure 12] This is a schematic cross-sectional view showing another conventional battery sensor. [Modes for carrying out the invention]

[0010] The form of this disclosure may be specified by the following configurations and features. A battery pack according to one embodiment of the present disclosure comprises a battery block having a plurality of battery cells arranged in fixed positions, and an electrical block having electrical components installed to control the charging and discharging current of the battery block, wherein the battery pack comprises an output terminal installed on the electrical block, a busbar of a power line electrically connecting the output terminal and the battery block, and a current sensor for detecting the current of the busbar, the busbar comprises a first busbar of a metal plate connected to the output terminal, a second busbar of a metal plate connected to the battery block, and a metal cylinder connecting the first busbar and the second busbar, the current sensor is a sensor for detecting the current of the metal cylinder, the electrical block comprises a sensor housing for housing the current sensor and a busbar guide portion having the second busbar arranged in fixed positions, and the current sensor, the first busbar and the second busbar are installed on the electrical block.

[0011] The battery pack described above has the advantage of being able to accurately detect current while maintaining high reliability over a long period of time, even in operating environments subject to vibration and shock, by installing the current sensor in a fixed position without misalignment. This advantage is achieved through a unique structure in which the battery pack consists of a first busbar, a second busbar and a metal cylinder connected in series, the metal cylinder which detects current is sandwiched between the first and second busbars, the current sensor which detects current in the metal cylinder is housed in a sensor housing provided in the electrical block and positioned in a fixed position, and the second busbar is placed in a busbar guide section provided in the electrical block and positioned in a fixed position, thereby installing the current sensor, the first busbar and the second busbar in fixed positions in the electrical block.

[0012] In addition to the above embodiments, a battery pack according to another embodiment of the present disclosure may be configured such that the current sensor is a magnetic current sensor having a ring-shaped magnetic core, a metal cylinder is placed inside the magnetic core, and a signal terminal is provided on the current sensor to detect and output the current flowing through the metal cylinder, and the first busbar is fixed to one end of the metal cylinder and the second busbar is fixed to the other end of the metal cylinder, with the first busbar and the second busbar fixed to the top and bottom of the metal cylinder, thereby connecting the battery block and the output terminal.

[0013] In addition to the above aspects, a battery pack according to another embodiment of the present disclosure has a metal cylinder provided with a through hole, and the first bus bar and the second bus bar each have a screw hole for fixing to the metal cylinder. A bolt passes through the screw hole of the first bus bar, the screw hole of the second bus bar, and the through hole, and a nut into which the bolt is screwed is positioned on the electrical block and arranged on the back surface of the second bus bar. The bolt and the nut can fix the current sensor and the bus bar.

[0014] In addition to the above aspects, a battery pack according to another embodiment of the present disclosure has a bolt with its head arranged on the back surface of the second bus bar, and the threaded portion passes through the second bus bar, the metal cylinder, and the first bus bar and is screwed into the nut on the surface of the first bus bar. The bolt and the nut can fix the current sensor and the bus bar.

[0015] In addition to the above aspects, a battery pack according to another embodiment of the present disclosure has an electrical block provided with a layout holder on which electrical components, output terminals, and a current sensor are installed, and the layout holder can be provided with a sensor housing portion and a bus bar guide portion for positioning the second bus bar in a fixed position.

[0016] In addition to the above aspects, a battery pack according to another embodiment of the present disclosure has a current sensor provided with a sensor case in which signal terminals are arranged in a fixed position, and the sensor case can be arranged in a sensor housing portion provided in the layout holder.

[0017] In addition to the above embodiments, battery packs according to other embodiments of the present disclosure have a sensor case having a mating recess for a female connector that is detachably connected to the signal terminal, and the female connector can be inserted into the mating recess to electrically connect the female connector to the signal terminal. The above battery packs have the advantage that the female connector, which is detachably connected to the current sensor, can be quickly attached to and detached from the fixed position of the sensor case, thereby suppressing poor contact of the signal terminal. This is because the female connector, which is detachably connected to the signal terminal, is inserted into the mating recess in an accurate position and orientation without misalignment, and the contacts of the signal terminal of the current sensor and the female connector can be maintained in a desirable contact state.

[0018] In addition to the above embodiments, battery packs according to other embodiments of the present disclosure may include a plurality of battery units in which the battery block is connected in series or in parallel.

[0019] In addition to the above embodiments, battery packs according to other embodiments of the present disclosure include a current sensor with a sensor case having signal terminals positioned in a fixed location, and the sensor case can be fixed to a layout holder of the electrical block. These battery packs have the advantage that, in addition to the current sensor being positioned in a fixed location on the electrical block via a first busbar, a second busbar and signal terminals, the sensor case is also fixed to the battery block, allowing the current sensor to be fixed to the battery block more reliably without displacement. A current sensor that is reliably fixed to the battery block has the advantage that relative displacement between the battery block and the current sensor is suppressed, relative displacement between the signal terminal of the current sensor and the female connector contact connected to the signal terminal is suppressed, and poor contact of the signal terminal can be more reliably suppressed and prevented.

[0020] In addition to the above embodiments, battery packs according to other embodiments of the present disclosure may include a voltage detection circuit in which a metal cylinder is a shunt resistor for detecting the current in a power line, and a current sensor detects the voltage induced across both ends of the metal cylinder to detect the current in the power line.

[0021] In addition to the above embodiments, battery packs according to other embodiments of this disclosure can be used as a power source to supply power to the motor of an electric vehicle.

[0022] The present disclosure will be described in detail below with reference to the drawings. In the following description, terms indicating specific directions or positions (e.g., "up," "down," and other terms including these) will be used as needed. The use of these terms is for the purpose of facilitating the understanding of the invention with reference to the drawings, and the meaning of these terms does not limit the technical scope of the present invention. Also, parts with the same reference numerals appearing in multiple drawings indicate the same or equivalent parts or components. Furthermore, the embodiments described below illustrate specific examples of the technical concept of the present invention and do not limit the present invention to those described below. Also, the dimensions, materials, shapes, relative arrangements, etc., of the components described below are intended to be illustrative, and not to limit the scope of the present invention unless otherwise specified. Moreover, the content described in one embodiment or example is applicable to other embodiments and examples. Additionally, the size and positional relationships of the members shown in the drawings may be exaggerated for clarity.

[0023] This disclosure does not specify an application for the battery pack, but can be used for all battery packs equipped with a current sensor. In particular, the battery pack of this disclosure can be useful for power sources that require excellent characteristics against vibration and shock, such as electric vehicles such as electric motorcycles, electric scooters, electric carts, electric assist bicycles, and hybrid vehicles, as well as construction machinery. It can also be used as a power source for portable electrical equipment such as wireless devices, electric cleaners, and power tools, or as a backup power source for servers or as a power supply for homes, offices, and factories in stationary energy storage applications where earthquake-resistant construction is required. (Embodiment 1)

[0024] Figures 1 to 3 show the battery pack 100 according to Embodiment 1, and Figures 4 to 10 show the electrical block 3B and current sensor 30. In these figures, Figure 1 is a perspective view of the battery pack 100 according to Embodiment 1, Figures 2 and 3 are exploded perspective views of the battery pack 100 of Figure 1, Figure 4 is a perspective view of the electrical block 3B of Figure 2, Figure 5 is an exploded perspective view of the electrical block 3B of Figure 4, Figure 6 shows the sensor case 33 and signal terminal 32 of the current sensor 30, Figure 7 is a plan view of the electrical block 3B of Figure 4, Figure 8 is a vertical cross-sectional view along line VIII-VIII of Figure 7, Figure 9 is a vertical cross-sectional view along line IX-IX of Figure 7, and Figures 10 and 11 show other embodiments. The battery pack 100 illustrated in Figures 1 to 3 comprises a battery block 3A in which a plurality of battery cells 1 are arranged in fixed positions in a battery holder 2, and an electrical block 3B fixed to the battery block 3A. The electrical component block 3B includes a layout holder 46 that controls the charging and discharging current of the battery block 3A and positions electrical components such as relays and semiconductor switching elements in fixed locations. The layout holder 46 can be manufactured by molding insulating plastic. In Figure 1, the battery pack 100 has the electrical component block 3B fixed on top of the battery block 3A, but the battery pack 100 does not specify the vertical arrangement of the battery block 3A and the electrical component block 3B. For example, although not shown, the electrical component block 3B can also be placed on the side of the battery block 3A.

[0025] Furthermore, the battery pack 100 in Figure 1 includes an output terminal 11 installed on the electrical block 3B, a busbar 20 of the power line 10 that electrically connects the output terminal 11 to the battery block 3A, and a current sensor 30 that detects the current of the busbar 20. The output terminals 11 (11A, 11B) illustrated in Figures 4 and 5 include a metal block with a terminal on its front and an intermediate metal plate connecting this metal block to the busbar 20. The metal block and the intermediate metal plate, and the intermediate metal plate and the busbar 20 can be fixed by screw fastening, with fixing bolts 49 fixing the intermediate metal plate to the busbar 20. The terminals in Figures 4 and 5 allow a knob with a female screw hole to be screwed into a horizontal screw protruding from the front of the metal block. This output terminal 11 can be connected to an external load power line (not shown) by screwing the knob into the horizontal screw, and the external load power line can be disconnected from the output terminal 11 by loosening the knob. This output terminal 11 has the feature that the power lines of an external load can be detachably connected by rotating a knob. This disclosure does not specify the shape, structure, configuration, or connection method of the output terminal 11 to the busbar 20, and all output terminals that can be connected to the power lines of an external load can be used. For example, the output terminal 11 can be the tip of the busbar 20 (the end opposite to the end connected to the current sensor 30), and the power lines of the external load can be directly connected to the busbar 20.

[0026] The busbar 20 comprises a first busbar 21 made of a metal plate connected to the output terminal 11, a second busbar 22 made of a metal plate connected to the battery block 3A, and a metal cylinder 31 connecting the first busbar 21 and the second busbar 22. The current sensor 30 is a sensor that detects the current in the metal cylinder 31, and for example, a magnetic current sensor described later can be used. However, this disclosure does not limit the current sensor 30 to a magnetic current sensor, and a current sensor that uses the metal cylinder 31 as a shunt resistor and detects the voltage induced across its ends in proportion to the current flowing through the metal cylinder 31 with a voltage detection circuit 47 can also be used. Figure 1 shows an example of a battery pack 100, but this disclosure does not specify the shape, size, number, arrangement, connection, or structure of the battery block 3A or the electrical block 3B or the battery cell 1 (battery unit 4). (Electrical block 3B)

[0027] The electrical block 3B includes electrical components, as well as a current sensor 30 and a busbar 20, which are positioned in their respective locations. The electrical block 3B is provided with a sensor housing section 44 for housing the current sensor 30 in a plastic layout holder 46, and a busbar guide section 43 for positioning the second busbar 22 in its designated location. The current sensor 30 is installed in the sensor housing section 44, and the second busbar 22 is installed in the busbar guide section 43, and both are positioned in their respective locations within the layout holder 46.

[0028] The electrical block 3B is provided with an output terminal 11 for the power line 10, and a busbar 20 is connected to the output terminal 11. The busbar 20 consists of a first busbar 21, a second busbar 22, and a metal cylinder 31 connected in series, and the current in the metal cylinder 31 is detected by a current sensor 30. The current sensor 30 is a magnetic current sensor with a magnetic core arranged around the metal cylinder 31. The sensor case 33, which houses the magnetic core, is placed in the sensor housing section 44 of the layout holder 46 and installed in a fixed position on the electrical block 3B. The metal cylinder 31, which the current sensor 30 detects, is inserted into a positioning hole 45 of the sensor case 33, and bolts 41 and nuts 42 connect the first busbar 21 and the second busbar 22, so that the first busbar 21 and the second busbar 22 clamp the top and bottom of the metal cylinder 31, and the electrical block 3B installs the current sensor 30 and the metal cylinder 31 in a fixed position. (Battery block 3A, electrical block 3B)

[0029] The battery block 3A in Figure 1 comprises multiple battery units 4 arranged in multiple stages (three stages in Figure 1). Each of the multiple battery units 4 has multiple battery cells 1 arranged vertically with their upper and lower end faces on the same plane. Each battery unit 4 connects each battery cell 1, whose upper and lower end faces are on the same plane, in parallel or in series via connecting lead plates. The connecting lead plates are metal plates thinner than the busbars 20 and are arranged on both the upper and lower surfaces or one side of the battery unit 4, and are connected to the positive and negative electrodes of each battery cell 1.

[0030] In Figures 1 and 2, the battery block 3A has battery units 4 arranged in three stages from the bottom: the first, second, and third stages. Each battery block 3A is connected in series and connected to the output terminal 11. The second and third battery units 4 are stacked in multiple stages on top of the bottom battery unit 4, or the first stage battery unit 4. This battery block 3A connects the first stage battery unit 4 and the second and third stage battery units 4 in series. The three battery units 4, connected in series with each other, are connected to the output terminal 11 via the busbar 20. One output terminal 11A is connected to the bottom (first stage) battery unit 4 via a series circuit of the first busbar 21, the metal cylinder 31, and the second busbar 22. The other output terminal 11B is connected to the top (third stage) battery unit 4 via the third busbar 23. (Current sensor 30)

[0031] The current sensor 30 can be a magnetic current sensor equipped with a ring-shaped magnetic core surrounding a metal cylinder 31. The magnetic current sensor has the magnetic core built into a sensor case 33. The sensor case 33 is provided with a positioning hole 45 for positioning the metal cylinder 31 in a fixed position, and the magnetic core is positioned around the positioning hole 45. The metal cylinder 31 is inserted into the positioning hole 45 of the sensor case 33, and the magnetic core is positioned around the metal cylinder 31. The current sensor 30 has a magnetic sensor built into the sensor case 33 that detects and outputs the current flowing through the metal cylinder 31. The current sensor 30 shown in Figures 4 to 6 shows a sensor case 33 that incorporates a magnetic core (not shown). The current sensor 30 outputs the signal from the magnetic sensor that detects the magnetic flux of the magnetic core as a current signal from the signal terminal 32. The sensor case 33 that incorporates the magnetic core is preferably made of thermoplastic plastic so that the magnetic core can be positioned in a fixed position. In the plastic sensor case 33, multiple signal terminals 32 are insert-molded and fixed in a fixed position. The signal terminal 32 can output a current signal via a connector or by soldering a lead wire. The current signal output from the signal terminal 32 via the connector is input to a control circuit (not shown) that controls the charging and discharging of the battery via a wire harness (not shown).

[0032] Figure 11 shows a current sensor 30 using a metal cylinder 31 as a shunt resistor. In this figure, the current sensor 30 detects the current in the metal cylinder 31 by detecting the voltage across the metal cylinder 31 used as a shunt resistor with a voltage detection circuit 47. The voltage detection circuit 47 is a differential amplifier that amplifies the voltage across the metal cylinder 31, and outputs the output of the differential amplifier to the outside from the signal terminal 32. This current sensor 30 is set to an optimal value based on the electrical resistance of the metal cylinder 31 and the amplification factor of the voltage detection circuit 47 at the maximum current at which it is detected. This current sensor 30 can reduce power loss at high currents by reducing the electrical resistance of the metal cylinder 31, which is the shunt resistor. By reducing the electrical resistance of the metal cylinder 31, the current sensor 30 can stably detect the current from the output voltage by increasing the amplification factor of the voltage detection circuit 47. In the current sensor 30 using a metal cylinder 31 as a shunt resistor, an insulating bolt 41 is used to prevent a short circuit between the ends of the metal cylinder 31 by the metal bolt 41, or, although not shown, an insulating material is placed between the bolt 41 and either or both of the first busbar 21 and the second busbar 22 and the bolt 41 to prevent a short circuit between the ends of the metal cylinder 31 by the metal bolt 41. In the current sensor 30 using a metal cylinder 31 as a shunt resistor, although not shown, heat dissipation fins can be fixed to the surface of the metal cylinder 31 to prevent temperature rise.

[0033] As shown in Figure 1, the battery pack 100 has a circuit board 48 placed on the side of the battery block 3A, and the control circuit can be configured with this circuit board 48 and a switching element (not shown) mounted on the electrical block 3B. The control circuit controls the charging and discharging current of the battery block 3A from the current signal input from the current sensor 30, and further controls the switching element with a signal input from a circuit that detects the voltage of the battery cell 1 and the battery unit 4 (not shown), thereby ensuring the safety of the battery pack 100 and controlling the charging and discharging current to prevent deterioration of the battery cell 1 and extend its lifespan. Poor contact between the signal terminal 32 and the connector is the biggest obstacle to the safety of the battery pack 100, so poor contact at the signal terminal 32 severely restricts or makes the battery pack 100 unusable. For this reason, it is extremely important for the current sensor 30 to reduce poor contact at the signal terminal 32. To reduce and minimize contact failures at the signal terminal 32, it is important to not only position the signal terminal 32 in a precise orientation but also to suppress relative displacement between the signal terminal 32 and the connector. In the current sensor 30 shown in Figures 4, 5, 7, and 8, a metal cylinder 31 is sandwiched between a first busbar 21 connected to the output terminal 11A and a second busbar 22 located in the busbar guide section 43 of the electrical block 3B, and this metal cylinder 31 is placed in the sensor case 33 of the battery cell 1, thereby positioning the signal terminal 32 of the current sensor 30 in a specific orientation. The battery pack 100 with this structure effectively prevents contact failures at the signal terminal 32 even under harsh operating conditions involving vibration and shock, and can stably and accurately detect the current of the busbar 20 over a long period of time.

[0034] The current sensor 30 shown in Figures 5 and 8 is a magnetic current sensor in which a metal cylinder 31 is placed inside a magnetic core, and multiple signal terminals 32 are fixed in place within a sensor case 33. The sensor case 33 can be positioned in place by inserting the metal cylinder 31 into a cylindrical positioning hole 45 that runs through the top and bottom of the case. The inner shape of the positioning hole 45 is made approximately equal to the outer shape of the metal cylinder 31, so that the metal cylinder 31 can be inserted into the positioning hole 45 and press-fitted to position it in place.

[0035] The metal cylinder 31, inserted into the positioning hole 45 of the sensor case 33, is fixed vertically to the first bus bar 21 and the second bus bar 22 with bolts 41 and nuts 42, connecting the first bus bar 21 and the second bus bar 22 in series. The current flowing through the cylinder is detected by the current sensor 30 and output from the signal terminal 32. The magnetic current sensor 30 detects the magnetic flux induced in the magnetic core by the current flowing through the metal cylinder 31 and outputs it as a current signal from the signal terminal 32. The bolts 41 and nuts 42 are screw-fastened to clamp and fix the metal cylinder 31 between the first bus bar 21 and the second bus bar 22, positioning them in their respective locations. The bolt 41 has a head 41a and a shaft. The length of the shaft is sufficient if the tip with the male threaded portion protrudes from the bus bar 20 so that the nut 42 can be screwed in. (Bus bar 20)

[0036] The busbar 20 consists of a first busbar 21, a second busbar 22, and a metal cylinder 31, forming the power line 10 of the battery pack 100 and connecting the battery block 3A to the output terminal 11. The busbar 20 of the battery pack 100, as shown in Figures 1 and 4, can be manufactured from conductive metal plates to form the first busbar 21, the second busbar 22, and the third busbar 23. The metal cylinder 31 can be manufactured by forming a conductive metal into a cylindrical shape, similar to the first busbar 21 and the second busbar 22. The busbar 20 of the power line 10, which consists of the first busbar 21, the metal cylinder 31, and the second busbar 22, connects one output terminal 11A to the lowest battery unit 4 of the battery block 3A. The third busbar 23 connects the other output terminal 11B to the uppermost battery unit 4 of the battery block 3A.

[0037] The busbar 20 can be made from, for example, copper, aluminum, nickel, zinc, or iron, or from an alloy containing any of these materials, or from a metal plate such as iron with nickel or copper plating on the surface. The thickness and width of the metal busbar 20 are determined to an optimal value based on the current flowing through the power line 10. The battery pack 100, which has multiple battery cells 1 connected in series and parallel, can be used for applications with large load currents. For example, the battery pack 100 can reduce the generation of Joule heat, which increases proportionally to the square of the current, by making the metal busbar 20 from a metal plate with a thickness of 1 mm or more and a width of 5 mm or more. The cross-sectional area of ​​the metal busbar 20 is appropriately set according to the maximum current supplied to the load, and the thickness and width of the metal busbar 20 are set accordingly. The first busbar 21, the second busbar 22, and the third busbar 23 carry the same load current, so preferably they are made of the same material and have the same thickness and width. The metal cylinder 31 is formed from metal into a cylindrical shape (preferably a columnar shape), preferably with a thickness of 1 mm or more, an outer diameter equal to the width of the metal plate, and a cross-sectional area set according to the maximum current supplied to the load.

[0038] The first busbar 21, the second busbar 22, and the third busbar 23 are each provided with screw holes 21a, 21b, 22a, 22b, 23a, 23b, 24a, and 24b at their ends, allowing them to be connected and fixed to each part by screw fastening. The first busbar 21 is positioned in a horizontal plane, with one end connected to the output terminal 11A via screw hole 21a, and the other end fixed to the metal cylinder 31 by inserting a bolt 41 into screw hole 21b. The busbars 20 have shapes that can be positioned according to the outer shape of the battery block 3A and the arrangement and shape of the battery holder 2. The second busbar 22, illustrated in Figures 4 and 5, is made by bending a metal plate to create a shape that connects a vertical busbar section 22A and a horizontal busbar section 22B in an integrated structure. The vertical busbar section 22A is connected and fixed at its lower end via a screw hole 22a to the battery-side busbar 24 which is stacked on the upper surface of the lowest first-stage battery unit 4, and the horizontal busbar section 22B is fixed at its end to the lower surface of the metal cylinder 31 via a screw hole 22b. The third busbar 23 has one end connected to the output terminal 11B via a screw hole 23a and the other end connected to the upper part of the battery block 3A via a screw hole 23b.

[0039] A pair of output terminals 11A and 11B are located on the top of the electrical block 3B, with one output terminal 11A connected to the lowest battery unit 4 of the battery block 3A, and the other output terminal 11B connected to the uppermost battery unit 4 of the battery block 3A. The first busbar 21 and the second busbar 22, which connect the lowest battery unit 4 to the output terminal 11A, are connected in series via a metal cylinder 31 inserted into the positioning hole 45 of the current sensor 30. One end of the first busbar 21 is fixed to the output terminal 11A, and the other end is connected to the upper surface of the metal cylinder 31 inserted into the positioning hole 45 of the current sensor 30 (the upper end of the metal cylinder 31 in Figures 4, 5, 8, and 9). The second busbar 22 has one end connected to the back surface of the metal cylinder 31 (the lower end of the metal cylinder 31 in Figures 4, 5, 8, and 9) which is inserted into the positioning hole 45 of the current sensor 30, and the other end connected to the battery unit 4 at the bottom.

[0040] Figures 4, 5, 7-10 show a structure in which a bolt 41 and a nut 42 fix the first bus bar 21 and the second bus bar 22 to a metal cylinder 31 into which the positioning hole 45 of the current sensor 30 is inserted. In the fixing structure of Figures 8 and 9, the nut 42 is placed on the back surface (bottom surface in Figure 9) of the second bus bar 22, and the bolt 41 passes through the first bus bar 21, the metal cylinder 31 and the second bus bar 22 from above and is screwed into the nut 42 below, fixing the first bus bar 21 and the second bus bar 22 to the metal cylinder 31. In this fixing structure, the nut 42 is fixed to the back surface of the second bus bar 22, or a fitting recess 50 is provided in the layout holder 46 to guide the nut 42 into the fitting structure, which prevents the nut 42 from rotating (rotating together) when the bolt 41 is screwed in. The nut 42 can be welded or glued to the back surface of the second busbar 22. Once the nut 42 is fixed to the second busbar 22, the bolt 41 can be rotated and screwed into the nut 42 to securely fix the first busbar 21 and the second busbar 22 to the top and bottom of the metal cylinder 31. However, the nut 42 does not necessarily need to be fixed to the second busbar 22 or guided into the fitting recess 50. This is because the frictional resistance between the nut 42 and the surface of the second busbar 22 prevents the nut 42 from rotating, allowing the bolt 41 to be screwed in.

[0041] The above-described fixed structure allows the metal cylinder 31 inserted into the positioning hole 45 of the current sensor 30 to be connected to the first bus bar 21 and the second bus bar 22 in the following steps, thereby electrically connecting the battery block 3A to the output terminal 11. (1) The nut 42 is set on the lower surface of the tip of the horizontal busbar portion 22B of the second busbar 22 at the position where it connects to the metal cylinder 31. The nut 42 is positioned coaxially with the screw hole 22b provided at the tip of the horizontal busbar portion 22B. The nut 42 can be fixed in place by welding or bonding it to the lower surface of the horizontal busbar portion 22B. Alternatively, the nut 42 can be set in place by being guided into the fitting recess 50 provided in the layout holder 46.

[0042] (2) The second bus bar 22 is set in the bus bar guide portion 43 of the electrical block 3B and its lower end is screwed to the battery-side bus bar 24 which is fixed to the battery block 3A. The second bus bar 22 and the battery-side bus bar 24 can be fixed by inserting set screws into the screw holes 22a and 24b provided at their ends and screwing them into the female screw holes (not shown) provided in the battery block 3A. (3) The screw hole 21a at one end of the first bus bar 21 is positioned in a fixed position, and the screw hole 21b at the other end is positioned on the central axis of the metal cylinder 31 inserted into the positioning hole 45 of the current sensor 30. The bolt 41 is inserted into the screw hole 21b of the first bus bar 21, the through hole of the metal cylinder 31, and the screw hole 22b of the second bus bar 22, and screwed into the nut 42 placed on the back surface of the second bus bar 22, thereby clamping the metal cylinder 31 between the first bus bar 21 and the second bus bar 22. The current sensor 30 is placed in the sensor housing 44 via the metal cylinder 31 fixed to the first bus bar 21 and the second bus bar 22 and set in a fixed position, and the current sensor 30 is screwed and fixed to the layout holder 46. After that, one end of the first bus bar 21 is fixed to the output terminal 11.

[0043] Figure 10 shows a configuration where a bolt 41 is positioned above and a nut 42 below. The bolt 41 passes through the first busbar 21, the current sensor 30, and the second busbar 22 from above and is screwed into the nut 42 below. The bolt 41 and nut 42 clamp the components together from both above and below, securing them with screws. However, as shown in Figure 10, the vertical positions of the bolt 41 and nut 42 can be reversed. In the fixing structure of Figure 10, the head 41a of the bolt 41 is positioned on the back surface (bottom surface in Figure 10) of the second busbar 22. The shaft of the bolt 41 passes through the second busbar 22 (screw hole 22b), the metal cylinder 31, and the first busbar 21 (screw hole 21b) from below and is screwed into the nut 42 positioned on the surface (top surface in Figure 10) of the first busbar 21, thereby fixing the first busbar 21 and the second busbar 22 to the top and bottom of the metal cylinder 31. This fixing structure prevents the bolt 41 from rotating (rotating together) when the nut 42 is screwed in, by fixing the head 41a of the bolt 41 to the back surface of the second bus bar 22, or by providing a fitting recess 50 in the sensor case 33 that guides the head 41a of the bolt 41 into the fitting structure. The head 41a of the bolt 41 can be fixed to the back surface of the second bus bar 22 by welding or bonding. The bolt 41 fixed to the second bus bar 22 can be securely fixed to the top and bottom of the metal cylinder 31 of the current sensor 30 by screwing a nut 42 onto its shaft. However, even in this structure, it is not always necessary to fix the bolt 41 to the second bus bar 22 or guide it into the fitting recess 50. This is because the frictional resistance between the bolt 41 and the back surface of the second bus bar 22 can keep the bolt 41 from rotating, allowing the nut 42 to be screwed in.

[0044] The fixed structure in Figure 10 allows the first busbar 21, the second busbar 22, and the current sensor 30 to be positioned in fixed locations through the following steps. (1) The head 41a of the bolt 41 is set in the fitting recess 50 of the layout holder 46 and positioned vertically. (2) Insert the screw hole 22b of the second busbar 22 into the vertical bolt 41 to position the second busbar 22 in place. In this state, the second busbar 22 is placed on the busbar guide portion 43 and set in place. (3) The current sensor 30 is placed in the sensor housing 44 and set in the fixed position, the metal cylinder 31 is inserted into the positioning hole 45 of the current sensor 30, and the bolt 41 is inserted into the through hole of the metal cylinder 31. This process sets the current sensor 30 in the fixed position on the layout holder 46. The metal cylinder 31 can be positioned in the fixed position by inserting it onto the bolt 41, with the inner diameter of the through hole being approximately equal to the outer diameter of the bolt 41. In this state, the current sensor 30 is fixed to the layout holder 46. However, fixing the current sensor 30 to the layout holder 46 can also be done after the metal cylinder 31 has been clamped between the first bus bar 21 and the second bus bar 22. (4) Insert the screw hole 21b provided at one end of the first bus bar 21 into the threaded portion of the bolt 41 protruding from the metal cylinder 31, and connect the screw hole 21a provided at the other end to the output terminal 11A, thereby positioning the first bus bar 21 in place. (5) A nut 42 is screwed onto the threaded portion of the bolt 41 protruding from the first bus bar 21, and the metal cylinder 31 is sandwiched between the first bus bar 21 and the second bus bar 22, and positioned in the fixed position of the layout holder 46, i.e., in the fixed position of the electrical block 3B. (6) The end of the first busbar 21 is fixed to the output terminal 11A. The first busbar 21 and the output terminal 11A can be fixed by screwing in terminal bolts, fixing bolts 49, etc. [Industrial applicability]

[0045] The battery pack according to this disclosure can be suitably used as a battery pack that can fix the signal terminals of the current sensor in a fixed position without misalignment, thereby achieving stable electrical connection of the signal terminals over a long period of time. [Explanation of Symbols]

[0046] 100...Battery pack 1…Battery cell 2…Battery holder 3A...Battery block 3B... Electrical block 4…Battery unit 10…Power lines 11, 11A, 11B… Output terminals 20... Bus bar 21... First bus bar 22... Second bus bar 22A...Vertical busbar section 22B... Horizontal busbar section 23... Third bus bar 24...Battery side busbar 21a, 21b, 22a, 22b, 23a, 23b, 24a, 24b... screw holes 30...Current sensor 31...Metal tube 32... Signal terminals 33... Sensor case 41... Bolt 41a...Head 42... Nut 43...Bus bar guide section 44...Sensor housing 45…Positioning holes 46…Layout holder 47...Voltage detection circuit 48... Circuit board 49… Fixing bolts 50…Matching recess 903... Power Module 920... Bus bar 930...Current sensor 931…Hollow conductor 941... Bolts

Claims

1. A battery block in which multiple battery cells are arranged in fixed positions, A battery pack comprising an electrical block having electrical components installed to control the charging and discharging current of the battery block, The output terminal installed in the aforementioned electrical block, The output terminal and the power line busbar that electrically connects the battery block, The system includes a current sensor that detects the current in the busbar, The aforementioned busbar is The first busbar of the metal plate connected to the output terminal, The second busbar of the metal plate connected to the battery block, The device comprises a metal cylinder connecting the first busbar and the second busbar, The current sensor is a sensor that detects the current in the metal cylinder, The aforementioned electrical block is A sensor housing section for housing the current sensor, The device comprises a busbar guide section in which the second busbar is positioned, A battery pack comprising the current sensor, the first busbar, and the second busbar installed in the electrical block.

2. A battery pack according to claim 1, The current sensor is It is a magnetic current sensor equipped with a ring-shaped magnetic core, The metal cylinder is placed inside the magnetic core, The system includes a signal terminal that detects and outputs the current flowing through the metal cylinder, The first busbar is fixed to one end of the metal cylinder, The second busbar is fixed to the other end of the metal cylinder, A battery pack comprising the first busbar and the second busbar fixed to the upper and lower parts of the metal cylinder, and the battery block and the output terminals being electrically connected.

3. The battery pack according to claim 2, The aforementioned metal cylinder is provided with a through hole, The first busbar and the second busbar are each provided with screw holes for fixing to the metal cylinder. The screw hole of the first busbar and the screw hole and through hole of the second busbar are opposite each other, and a bolt passes through the screw hole of the first busbar, the screw hole and through hole of the second busbar, The nut into which the bolt is screwed is positioned on the electrical block and placed on the back surface of the second busbar. A battery pack in which the bolt and nut secure the current sensor and the busbar.

4. The battery pack according to claim 2, The aforementioned metal cylinder is provided with a through hole, The first busbar and the second busbar are each provided with screw holes for fixing to the metal cylinder. The screw hole of the first busbar and the screw hole and through hole of the second busbar are opposite each other, and a bolt passes through the screw hole of the first busbar, the screw hole and through hole of the second busbar, The bolt is positioned with its head on the electrical block and placed on the back surface of the second busbar. The threaded portion of the bolt penetrates the second busbar, the metal cylinder, and the first busbar. The first busbar is screwed into a nut on its surface, A battery pack in which the bolt and nut secure the current sensor and the busbar.

5. A battery pack according to claim 1, The electrical block comprises a layout holder on which the electrical components, the output terminals, and the current sensor are installed. The aforementioned layout holder, A battery pack comprising the sensor housing and the busbar guide section that positions the second busbar in a fixed position.

6. The battery pack according to claim 2, The current sensor, The sensor case comprises the aforementioned signal terminals arranged in fixed positions, A battery pack in which the sensor case is placed in the sensor storage section provided in the layout holder.

7. The battery pack according to claim 6, The aforementioned sensor case The signal terminal has a mating recess for a female connector that is detachably connected to the aforementioned signal terminal, The female connector is inserted into the mating recess, A battery pack in which the female connector is electrically connected to the signal terminal.

8. A battery pack according to claim 1, The aforementioned battery block, A battery pack comprising multiple battery units connected in series or parallel.

9. The battery pack according to claim 2, The current sensor, The sensor case comprises the aforementioned signal terminals arranged in fixed positions, A battery pack in which the sensor case is fixed to the layout holder of the electrical block.

10. A battery pack according to claim 1, The aforementioned metal cylinder is a shunt resistor that detects the current in the power line. The current sensor detects the voltage induced at both ends of the metal cylinder, A battery pack equipped with a voltage detection circuit that detects the current in the power line.

11. A battery pack according to any one of claims 1 to 10, A battery pack that supplies power to the motor used to drive electric vehicles.

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