JP7550644B2 - Battery pack - Google Patents

Description

The present invention relates to a battery pack having a conductive connector on its bottom surface.

Battery packs are detachably mounted on electric vehicles such as electrically power-assisted bicycles and electric motorcycles. This type of battery pack is constructed by housing a battery core pack having multiple single cells inside the hollow interior of a case. The single cells are, for example, lithium secondary batteries, and are charged when their capacity drops to a certain level. This restores the capacity and makes it possible to discharge again.

A device-side conductive connector is provided at the bottom of a battery storage case for an electric vehicle or a battery receiving section of a charger. As described in JP 2013-164969 A, particularly in paragraphs [0042] and [0043] and FIG. 2, the device-side conductive connector is electrically connected to a battery-side conductive connector provided on the bottom of a battery pack (described as a "battery module" in JP 2013-164969 A). In general, the device-side conductive connector is a male connector, and the battery-side conductive connector is a female connector. That is, a male terminal constituting a male connector is inserted into a female terminal constituting a female connector. As a result, it becomes possible to supply power from the battery pack to an electric vehicle or the like, and conversely, to supply power from a charging device to the battery pack.

In order to insert the device-side conductive connector into the battery-side conductive connector, it is necessary to align the position of the battery-side conductive connector with the device-side conductive connector. In other words, the user must visually check the bottom of the battery pack and adjust the direction and posture of the battery pack so that the battery-side conductive connector and the device-side conductive connector are on the same axis. Such checking and adjustment work is cumbersome, and it is difficult to say that it is user-friendly.

The main object of the present invention is to provide a battery pack that does not require confirmation work to align conductive connectors with each other.

Another object of the present invention is to provide a battery pack that is highly convenient.

In order to achieve the above object, according to one embodiment of the present invention, there is provided a battery pack comprising a case for accommodating a battery core pack having a plurality of unit cells, the battery pack having a bottom surface provided with a conductive connector electrically connected to the unit cells,
The conductive connector has one first terminal exhibiting a first polarity and two second terminals exhibiting a second polarity,
There is provided a battery pack in which the first terminal is located at the center of the bottom surface, and the two second terminals are arranged with the first terminal as a center of line symmetry.

Note that the "first polarity" refers to either the positive or negative pole, and therefore the "first terminal" is either the positive or negative terminal. The "second polarity" refers to either the negative or positive pole, and the "second terminal" refers to either the negative or positive pole. For example, when the first terminal is a positive terminal, the second terminal is a negative terminal, and when the first terminal is a negative terminal, the second terminal is a positive terminal.

By arranging the electrode terminals as described above, the battery side conductive connector can be engaged with the external load conductive connector or the charging device conductive connector to electrically connect both conductive connectors, whether the battery pack is in the normal orientation or flipped 180° from the normal orientation. This eliminates the need for the user to look into the bottom of the battery pack to check the orientation of the battery pack or to twist their wrist to view the bottom. This makes it easier to attach the battery pack to the external load or charging device, improving convenience.

It is preferable that the bottom surface of the case is rectangular in plan view. In this case, the position of the center of the bottom surface can be easily determined. This makes it easy to align the conductive connectors with each other, allowing the conductive connectors to be reliably engaged with each other. Furthermore, if the bottom surface is rectangular, when the battery pack is rotated 90 degrees from the normal orientation, the long side of the bottom surface will interfere with the short side of the opening of the battery storage case of the external load or charging device. This makes it possible to prevent the battery pack from being inserted into the battery storage case in this orientation.

In this case, the term "rectangle" includes not only those with right-angled vertices, but also those with chamfered vertices to form rounded corners. "Rectangle" also includes "square."

The number of first terminals is smaller than the number of second terminals. Therefore, at the second terminals, the current exchanged between the second terminal of the conduction connector of the external load or charging device branches off. Therefore, the contact area between each second terminal and each second terminal of the conduction connector of the external load or charging device can be made smaller than the contact area between the first terminal and the first terminal of the conduction connector of the external load or charging device. This allows the second terminal, and therefore the conduction connector, to be made smaller.

According to the present invention, the conductive connector provided on the bottom surface of the battery pack is configured to include one first terminal located at the center of the bottom surface and exhibiting a first polarity, and two second terminals arranged with the first terminal as the center of line symmetry and exhibiting a second polarity. Therefore, when the battery pack is in the normal orientation or when it is inverted 180° from the normal orientation, the conductive connector can be engaged with the conductive connector of an external load or a charging device to electrically connect the two conductive connectors.

Therefore, it is not necessary for the user to check the orientation of the battery pack in advance. This makes it possible to easily attach the battery pack to an external load or charging device, improving convenience.

1 is a schematic overall perspective view of a battery pack according to an embodiment of the present invention; FIG. 2 is a schematic exploded perspective view of the battery pack. FIG. 4 is a bottom view of the bottom case that constitutes the case. 4 is a schematic vertical cross-sectional view of a battery-side connector (conductive connector) provided in the battery pack. FIG. 1 is a schematic perspective view of a device-side connector (conductive connector) provided in an external load; FIG. 1 is a longitudinal sectional view of a main portion showing a state in which the battery pack is oriented in a normal direction and the device-side connector faces the battery-side connector. 7 is a longitudinal sectional view of a main portion showing a state in which an electrode terminal of the device-side connector is inserted into an electrode terminal of the battery-side connector, taken from FIG. 6 . 11 is a longitudinal cross-sectional view of a main portion showing a state in which the battery pack is turned 180° from a normal orientation so that the device-side connector faces the battery-side connector. FIG. 9 is a longitudinal sectional view of the essential parts showing a state in which the electrode terminal of the device-side connector is inserted into the electrode terminal of the battery-side connector, taken from FIG. 8 .

Below, we will present a preferred embodiment of the battery pack according to the present invention and explain it in detail with reference to the attached drawings.

1 and 2 are respectively a schematic overall perspective view and a schematic exploded perspective view of a battery pack 10 according to the present embodiment. Note that in order to facilitate understanding of the configuration of the battery pack 10, the battery pack 10 is shown in a recumbent position in Figs. 1 and 2, but the battery pack 10 is primarily used in a position in which the longitudinal direction (height direction) extends along the direction of gravity, or in which the longitudinal direction is inclined relative to the direction of gravity.

The battery pack 10 has a hollow rectangular prism-shaped case 12 with both ends open, and a first battery core pack 14 and a second battery core pack 16 (see FIG. 2) housed in the hollow interior of the case 12. The case 12 has a case body 17, a bottom case 18 that closes the bottom opening of the case body 17, and a top case 20 that closes the ceiling opening. A battery side connector 22, which is a conductive connector for supplying (discharging) power from the first battery core pack 14 and the second battery core pack 16 or for supplying (charging) power to the first battery core pack 14 and the second battery core pack 16, is faced through a window 21 formed in the bottom case 18. On the other hand, a handle 24 is formed in an arch shape on the top case 20 for a user to grasp when lifting or transporting the battery pack 10.

The first battery core pack 14 is composed of a plurality of single cells 30 held in a first cell holder 32. In this case, the single cells 30 are cylindrical, and a positive terminal and a negative terminal (neither shown) are provided at both ends in the axial direction. A suitable example of the single cells 30 is a lithium-ion secondary battery, but is not limited to this, and other secondary batteries such as nickel-metal hydride batteries and nickel-cadmium batteries may also be used.

The first cell holder 32 has a plurality of cell accommodating holes 34 formed therethrough with a diameter and length corresponding to the diameter and height of the single cells 30, and the single cells 30 are individually inserted and held in each cell accommodating hole 34. The second battery core pack 16, like the first battery core pack 14, also has a second cell holder 36 with cell accommodating holes 34 formed therein, and is configured such that the single cells 30 are held in the cell accommodating holes 34. In addition, the first battery core pack 14 and the second battery core pack 16 are accommodated in the case 12 (mainly the case body 17) such that the longitudinal direction of the single cells 30 is perpendicular to the vertical direction of the battery pack 10. A positive terminal and a negative terminal are provided on both bottom surfaces, which are the longitudinal end surfaces.

The cell accommodating holes 34 are arranged in parallel along the horizontal direction (vertical direction in FIG. 2) of the first cell holder 32 and the second cell holder 36. A row of cell accommodating holes 34 arranged in a direction perpendicular to the longitudinal direction constitutes an accommodating hole row 37. In any accommodating hole row 37 of the first battery core pack 14, the single cells 30 are accommodated in the cell accommodating holes 34 with, for example, the positive terminal facing the second battery core pack 16. In another accommodating hole row 37 adjacent to the accommodating hole row 37, the single cells 30 are accommodated in the cell accommodating holes 34 with the negative terminal facing the second battery core pack 16. This alternating arrangement is repeated, so that in adjacent accommodating hole rows 37, the electrode terminals of opposite polarity face the same direction.

The positive terminal of any one of the rows of storage holes 37 and the negative terminal of another row of storage holes 37 adjacent thereto are electrically connected in series by the same bus bar 38. The same is true for the second battery core pack 16. The bus bar 38 connecting the unit cell 30 in the lowest row of storage holes 37 of the first battery core pack 14 and the unit cell 30 in the lowest row of storage holes 37 of the second battery core pack 16 has a curved portion facing the bottom case 18 and protrudes from the clearance between the first battery core pack 14 and the second battery core pack 16.

The case body 17, which mainly houses the first battery core pack 14 and the second battery core pack 16, has an outer frame 40 and a partition wall 42 that is integrally connected to the outer frame 40. The partition wall 42 extends along the vertical direction of the case body 17 and divides the hollow interior of the case body 17 into a first inner chamber 44 and a second inner chamber 46 of approximately the same volume. The first battery core pack 14 is housed in the first inner chamber 44, and the second battery core pack 16 is housed in the second inner chamber 46.

A battery management unit (BMU) 50, which is a control unit that manages the temperature and voltage of the first battery core pack 14 and the second battery core pack 16, is inserted between the top surface of the first battery core pack 14 (first cell holder 32) and the top case 20, and between the top surface of the second battery core pack 16 (second cell holder 36). The BMU 50 also serves as a communication unit that communicates with the electric vehicle and the charging device.

Next, the battery side connector 22 and the device side connector 60 (both conductive connectors) will be described in detail with reference to Figures 3 to 5.

3, the bottom surface of the bottom case 18 is rectangular in plan view, and a window 21 is opened in the center of the bottom surface. A base 62 constituting the battery-side connector 22 can be seen from the window 21. The base 62 is an insulator made of, for example, insulating resin, and is supported by the bottom case 18.

The base 62 has a generally rectangular parallelepiped shape, and its bottom surface faces the window portion 21. As shown in Fig. 4, the base 62 has three terminal accommodating holes 64a to 64c extending vertically from the bottom surface. In other words, the terminal accommodating holes 64a to 64c are arranged in parallel in a straight line along the longitudinal direction (height direction) of the battery pack 10.

The terminal accommodating holes 64a to 64c accommodate electrode terminals. If the positive electrode is the first polarity and the negative electrode is the second polarity, in this embodiment, the terminal accommodating hole 64b accommodates a female positive terminal 66 as a first terminal exhibiting the first polarity, and the terminal accommodating holes 64a and 64c accommodate female negative terminals 68a and 68b as second terminals exhibiting the second polarity. That is, the battery side connector 22 has one female positive terminal 66 and two female negative terminals 68a and 68b. The female positive terminal 66 and the female negative terminals 68a and 68b are both female terminals, and the battery side connector 22 is ultimately a female connector. The female positive terminal 66 and the female negative terminals 68a and 68b are good conductors made of metal such as copper.

Of course, the female positive terminal 66 is electrically connected to the positive terminal of the single cell 30, and the female negative terminals 68a, 68b are electrically connected to the negative terminal of the single cell 30.

Here, the intersection of the bisector L1 of the two long sides 70a, 70b of the bottom surface of the bottom case 18 and the bisector L2 of the two short sides 72a, 72b is the center of the bottom surface. The female positive terminal 66 is disposed in the center obtained in this way. On the other hand, the two female negative terminals 68a, 68b are provided with the female positive terminal 66 as the center of linear symmetry (or rotational symmetry). That is, the female negative terminals 68a, 68b are located at positions sandwiching the female positive terminal 66, and the female negative terminal 68a, the female positive terminal 66, and the female negative terminal 68b are aligned on the same line. In addition, the distance from the female negative terminal 68a to the female positive terminal 66 is the same as the distance from the female negative terminal 68b to the female positive terminal 66. In this specification, "same" includes an error within the allowable range, and the same applies hereinafter.

As can be seen from Figure 3, the length of the female positive terminal 66 along the short sides 72a, 72b of the bottom case 18 is set to be greater than the length of the female negative terminals 68a, 68b along the short sides 72a, 72b of the bottom case 18. Therefore, the female positive terminal 66 has a larger area than the female negative terminals 68a, 68b.

Furthermore, two guide holes 74a, 74b are formed on the underside of the base 62 at positions sandwiching the terminal accommodating holes 64a to 64c. The distance from the guide hole 74a to the terminal accommodating hole 64a is the same as the distance from the guide hole 74b to the terminal accommodating hole 64c. As described below, the battery pack 10 is positioned and fixed as the positioning pins 84a, 84b are inserted into the guide holes 74a, 74b.

The base 62 configured as described above is positioned and fixed to the bottom case 18, for example, by screws (not shown).

The battery pack 10 is mounted on an electric vehicle such as an electrically assisted bicycle or an electric motorcycle, and functions as a power supply source for powering a motor as an external load. As shown in Fig. 5, these electric vehicles are provided with a battery storage case 76 that stores the battery pack 10. The device-side connector 60 is disposed at the bottom of the battery storage case 76.

The horizontal cross section of the battery storage case 76 has a rectangular shape similar to that of the battery pack 10. That is, the opening of the battery storage case 76 has long sides 77a, 77b that are approximately the same length as the long sides 70a, 70b of the battery pack 10, and short sides 79a, 79b that are approximately the same length as the short sides 72a, 72b. The device-side connector 60 is disposed in the center of the bottom wall of the battery storage case 76, as determined above.

The device-side connector 60 has a support base 78, one male positive terminal 80 supported by the support base 78, and two male negative terminals 82a, 82b. The male positive terminal 80 and the male negative terminals 82a, 82b are both generally flat. The male positive terminal 80 has a larger area than the male negative terminals 82a, 82b. The male positive terminal 80 and the male negative terminals 82a, 82b are good conductors made of metal such as copper, as described above.

The position of the male positive terminal 80 corresponds to the position of the female positive terminal 66, and the positions of the male negative terminals 82a, 82b correspond to the positions of the female negative terminals 68a, 68b. In other words, the male negative terminals 82a, 82b are in a positional relationship that is linearly symmetric or rotationally symmetric with the male positive terminal 80, and therefore the male negative terminal 82a, male positive terminal 80, and male negative terminal 82b are aligned on the same straight line. In addition, the distance from the male negative terminal 82a to the male positive terminal 80 is the same as the distance from the male negative terminal 82b to the male positive terminal 80.

Positioning pins 84a and 84b are erected from the upper surface of the support base 78, extending toward the battery-side connector 22. That is, the positioning pins 84a and 84b sandwich the male negative terminal 82a, the male positive terminal 80, and the male negative terminal 82b between them. The distance from the positioning pin 84a to the male negative terminal 82a is the same as the distance from the positioning pin 84b to the male negative terminal 82b.

The battery pack 10 in this embodiment is basically configured as described above, and its effects will be explained next.

The charged battery pack 10 is stored, for example, in a battery storage case 76 of an electric vehicle. At this time, the user grasps the handle 24 and inserts the battery pack 10 into the hollow interior of the battery storage case 76 from an opening at the top. The battery pack 10 is moved along the battery storage case 76 to the bottom.

When the user inserts the battery pack 10 into the battery storage case 76 in the correct orientation, the female positive terminal 66 faces the male positive terminal 80 as shown in FIG. 6. At the same time, the female negative terminal 68a faces the male negative terminal 82a, and the female negative terminal 68b faces the male negative terminal 82b. In addition, the positioning pin 84a faces the guide hole 74a, and the positioning pin 84b faces the guide hole 74b. When the battery pack 10 is further moved downward in the battery storage case 76, the positioning pins 84a and 84b begin to enter the guide holes 74a and 74b. Thereafter, the positioning pins 84a and 84b are guided by the guide holes 74a and 74b, thereby aligning the device-side connector 60 and the battery-side connector 22. Furthermore, when the positioning pins 84 a, 84 b are inserted to a predetermined depth into the guide holes 74 a, 74 b, the battery pack 10 is positioned and fixed at a predetermined position within the battery storage case 76 .

At the same time as the guide holes 74a, 74b guide the positioning pins 84a, 84b, the male positive terminal 80 is inserted into the female positive terminal 66, and the male negative terminals 82a, 82b are inserted into the female negative terminals 68a, 68b, resulting in the engagement state shown in Figure 7. The female positive terminal 66 and the female negative terminals 68a, 68b open slightly when inserted, and then try to return to their original opening due to elastic action. Due to this elastic action, the male positive terminal 80 and the male negative terminals 82a, 82b are clamped between the female positive terminal 66 and the female negative terminals 68a, 68b.

That is, the battery side connector 22 and the device side connector 60 are electrically connected, making it possible to supply power from each single cell 30 to the electric vehicle. When the electric vehicle is started and begins to operate, the single cell 30 discharges. Note that information communication between the BMU 50 and the electric vehicle, such as information regarding the remaining capacity of the battery pack 10, is performed wirelessly.

The number of male positive terminals 80 and female positive terminals 66 is one each, and the number of male negative terminals 82a, 82b and female negative terminals 68a, 68b is two each. Therefore, even if the area of the male positive terminal 80 is set larger than that of each of the male negative terminals 82a, 82b as described above and the area of the female positive terminal 66 is set larger than that of each of the female negative terminals 68a, 68b, the contact resistance between the male positive terminal 80 and the female positive terminal 66 can be made approximately equal to the total contact resistance between the male negative terminals 82a, 82b and the female negative terminals 68a, 68b.

In other words, the area of a large number of electrode terminals can be made smaller than the area of a small number of electrode terminals. This allows the large number of electrode terminals to be made smaller, and therefore the battery side connector 22 and the device side connector 60 can be made smaller.

It is assumed that the user will insert the battery pack 10 into the battery storage case 76 by turning it 180 degrees. Even in this case, the male positive terminal 80 faces the female positive terminal 66 as shown in FIG. 8. As described above, the male positive terminal 80 is provided in the center of the bottom wall of the battery storage case 76, and the female positive terminal 66 is provided in the center of the bottom surface of the bottom case 18 that constitutes the battery pack 10. Therefore, even if the orientation of the battery pack 10 is 180 degrees opposite to the normal orientation, the male positive terminal 80 is located in the center of the bottom wall of the battery storage case 76, and the female positive terminal 66 is located in the center of the bottom surface of the bottom case 18.

The male negative terminals 82a, 82b are arranged with the male positive terminal 80 as the center of linear symmetry (or rotational symmetry). The same is true for the positioning pins 84a, 84b. Therefore, in this case, the female negative terminal 68b faces the male negative terminal 82a, and the female negative terminal 68a faces the male negative terminal 82b. The positioning pin 84a faces the guide hole 74b, and the positioning pin 84b faces the guide hole 74a. In this state, when the battery pack 10 is moved below the battery storage case 76, the positioning pins 84a, 84b enter the guide holes 74b, 74a. That is, the positioning pins 84a, 84b are guided by the guide holes 74b, 74a, and the device side connector 60 and the battery side connector 22 are aligned. Then, as shown in FIG. 9, the positioning pins 84a, 84b are inserted to a predetermined depth into the guide holes 74b, 74a, and the battery pack 10 is positioned and fixed at a predetermined position within the battery storage case 76.

At the same time, the male positive terminal 80 is inserted into and clamped by the female positive terminal 66, and the male negative terminals 82a, 82b are inserted into and clamped by the female negative terminals 68b, 68a. In this way, even when the direction of rotation of the battery pack 10 about its longitudinal axis is reversed by 180°, the battery side connector 22 and the device side connector 60 engage with each other and are electrically connected, making it possible to supply power from each single cell 30 to the electric vehicle. Thereafter, as described above, when the electric vehicle is started and begins to operate, the single cells 30 are discharged.

The battery-side connector 22 is provided on the bottom surface of the bottom case 18. Therefore, when a user wants to check the orientation of the battery pack 10 (battery-side connector 22), he or she must grasp the handle 24 and twist his or her wrist to get into a position that allows the user to see the bottom surface. However, the heavier the battery pack 10 is, the greater the strain on the user's wrist. In addition, the task of checking is itself cumbersome.

In contrast, by positioning the male positive terminal 80, the female positive terminal 66, the male negative terminals 82a, 82b, and the female negative terminals 68a, 68b in the above-mentioned positions, even when the battery pack 10 is rotated 180° from the normal orientation, it is possible to electrically connect the battery pack 10 to the electric vehicle in the same way as when it is in the normal orientation. This eliminates the need for confirmation work, reducing the burden on the user. It also improves convenience.

The bottom surface of the bottom case 18 is rectangular. Therefore, when the battery pack 10 is rotated 90° from the normal orientation, the long sides 70a and 70b interfere with the short sides 79a and 79b of the opening of the battery storage case 76. This prevents the battery pack 10 from being inserted into the battery storage case 76.

When the remaining capacity of the single cells 30 of the battery pack 10 becomes low and charging is required, the user grasps the handle 24 and removes the battery pack 10 from the battery storage case 76. The user then transports the battery pack 10 to a charging device and electrically connects the battery side connector 22 to the charging connector of the charging device. The charging connector is configured in the same manner as the device side connector 60. Therefore, the single cells 30 are charged whether the battery pack 10 is in the normal orientation or when it is rotated 180 degrees from the normal orientation.

The present invention is not limited to the above-described embodiments, and various modifications are possible without departing from the spirit and scope of the present invention.

For example, the electrode terminal (first terminal of first polarity) located at the center of each of the battery side connector 22 and the device side connector 60 may be a negative terminal, and the two electrode terminals (second terminals of second polarity) located on either side of it may be positive terminals.

It is also possible for the battery-side connector 22 to be a male connector, and for the device-side connector 60 and the charging connector to be female connectors. In this case, it is preferable to set the length of the male terminal of the battery-side connector 22 so that it does not protrude from the bottom case 18.

Reference Signs List 10: Battery pack 12: Case 14, 16: Battery core pack 17: Case body 18: Bottom case 21: Window portion 22: Battery side connector 30: Single cell 32, 36: Cell holder 34: Cell accommodating hole 37: Accommodating hole row 38: Bus bar 44, 46: Inner chamber 50: BMU
60: Device side connector 64a to 64c: Terminal receiving hole 66: Female positive terminal 68a, 68b: Female negative terminal 70a, 70b: Long sides 72a, 72b: Short sides 74a, 74b: Guide holes 76: Battery storage case 77a, 77b: Long sides 79a, 79b: Short sides 80: Male positive terminal 82a, 82b: Male negative terminal 84a, 84b: Positioning pins L1, L2: Bisector

Claims (7)

A battery pack (10) comprising a case (12) for accommodating a battery core pack (14, 16) having a plurality of unit cells (30), and a conductive connector (22) for electrically connecting to the unit cells is provided on a bottom surface of the case,
the battery pack functions as a power supply source for an external load when attached to the external load;
The conductive connector includes:
a first terminal (66) exhibiting a first polarity;
Two second terminals (68a, 68b) are arranged on either side of the first terminal and indicate a second polarity;
two guide holes (74a, 74b) for inserting two positioning pins provided on the external load , the two guide holes being disposed at positions sandwiching the first terminal;
having
the first terminal is located at a center of the bottom surface, the two second terminals are arranged at positions where the first terminal is a center of rotational symmetry, and the two guide holes are arranged at positions where the first terminal is a center of rotational symmetry ,
The battery pack has a grip (24) provided on a surface of the case opposite the bottom surface and adapted to be gripped by a user . The battery pack according to claim 1, wherein the bottom surface is rectangular in plan view. The battery pack according to claim 1 or 2, wherein the area of the first terminal is larger than the area of the second terminal. The battery pack according to any one of claims 1 to 3, wherein the conductive connector is a female connector. A battery pack according to any one of claims 1 to 4, in which an open window (21) is formed in the bottom surface of the case, and the conductive connector faces the window. 2. The battery pack according to claim 1, wherein the bottom surface is rectangular in plan view having two sides (70a, 70b) facing each other and another two sides (72a, 72b) facing each other;
The center of the bottom surface is an intersection point of the bisector (L1) of the two sides and the bisector (L2) of the other two sides,
The first terminal of the battery pack is disposed at a center portion of the bottom surface. 7. The battery pack according to claim 1, wherein the two guide holes are disposed at positions sandwiching the first terminal and the two second terminals.

Images