JP2023065953A - Battery packs and electrical equipment - Google Patents

Abstract

To provide a battery pack and electrical equipment that suppress the heat transfer of a battery cell.SOLUTION: In a battery pack 1 including a plurality of battery cells 41 to 50 and a holder 100 having insertion holes 61 to 70 into which the battery cells 41 to 50 are inserted and holding the battery cells 41 to 50, the holder 100 is configured to cover the entire outer peripheral surfaces of the battery cells 41 to 50, and some of the plurality of insertion holes (61, 65 to 70) are formed with concave portions (spaced portions) 81, 82 to 86 between the inner peripheral surfaces of the insertion holes and the outer peripheral surfaces of the battery cells 41, 42 to 48. The amount of heat transferred from the battery cells 41 to 43 to the holder 100 can be adjusted by arranging the positions and sizes of the concave portions (spaced portions) unevenly (asymmetrically) among the battery cells.SELECTED DRAWING: Figure 7

Description

The present invention relates to battery packs and electrical equipment.

A battery pack is known that incorporates a plurality of battery cells and is configured to be detachable from an electrical device main body. Such a well-known technique is disclosed, for example, in Japanese Unexamined Patent Application Publication No. 2002-200013. In the battery pack of Patent Document 1, a plurality of battery cells are supported by synthetic resin separators and housed in a battery pack case. Further, in Patent Document 1, in order to suppress the temperature rise of the battery cells arranged in the storage case, in the separator accommodated inside the storage case, grooves are formed in the solid portions between the battery cells. is provided, and a heat radiating member made of metal is fitted inside the groove. When the battery pack is discharged or charged, the heat of the battery cells is transferred to the bottom of the case body via the separator and the heat dissipation member.

WO2015/079840

Battery cells generate heat during discharging and charging. The heat of the battery cell is transferred to another adjacent battery cell through the separator. As a result, the temperature of the battery cells varies, and the degree of deterioration of the battery cells varies.

SUMMARY OF THE INVENTION An object of the present invention is to provide a battery pack and an electric device in which heat transfer of battery cells is suppressed.
Another object of the present invention is to provide a battery pack and an electrical device in which variation in temperature rise of battery cells is suppressed.

The typical features of the invention disclosed in the present application are as follows.
According to one aspect of the present invention, there is provided a battery pack including a plurality of battery cells and a separator that has a plurality of insertion holes into which the plurality of battery cells are inserted and supports the plurality of battery cells. each of the plurality of insertion holes has a facing surface facing the outer peripheral surface of the battery cell, and the facing surface of the first insertion hole among the plurality of insertion holes contacts the outer peripheral surface of the battery cell; and a separation portion in which a gap is formed between the battery cell and the outer peripheral surface of the battery cell. In other words, in a battery pack that includes a plurality of battery cells and separators that support the plurality of battery cells, the plurality of insertion holes has at least two types of first insertion holes and second insertion holes. The first insertion hole has a contact portion that contacts the outer peripheral surface of the battery cell, and a separation portion in which a gap is formed. The second insertion hole has only the contact portion and no separation portion is formed.

According to another feature of the present invention, the spaced portion of the first insertion hole is arranged asymmetrically in the vertical direction or asymmetrically in the horizontal direction with respect to the axis of the cylindrical battery cell. Also, the plurality of insertion holes have a second insertion hole adjacent to the first insertion hole, and the spacing portion is provided on the side of the first insertion hole where the second insertion hole is provided. A battery cell inserted into the second insertion hole has a higher temperature than a battery cell inserted into the first insertion hole. Also, the plurality of insertion holes are arranged adjacent to at least one of the first insertion hole and the second insertion hole, and configured to have a third insertion hole having a contact portion and a separation portion. Here, the third insertion hole is a hole having a spaced portion, and the size (area) and length (length in the circumferential direction) of the spaced portion are different from those of the first insertion hole. Further, the spaced portion between the first insertion hole and the third insertion hole may be configured such that the distance between the battery cell and the facing surface is different.

According to still another aspect of the present invention, there is provided a battery pack comprising a battery cell, a separator having a plurality of insertion holes into which each of the plurality of battery cells is inserted, and a separator supporting the plurality of battery cells, At least three of the plurality of insertion holes are arranged side by side in the front-rear direction. and a spaced portion in which a gap is formed between the outer peripheral surface. The separating portion is provided on the side where the centrally located insertion hole is provided. Also, the plurality of insertion holes have a second insertion hole adjacent to the first insertion hole. The separator has a connection portion that connects the first insertion hole and the second insertion hole in the direction in which the first insertion hole and the second insertion hole are aligned, and the dimension of the gap in the separation portion in the direction in which the first insertion hole and the second insertion hole are aligned is the dimension of the connection portion. configured to be smaller. Furthermore, the second insertion hole is configured to be provided in the central region of the separator.

According to still another feature of the present invention, an electric device comprising the above-described battery pack, a battery pack mounting portion to which the battery pack is mounted, and an electric device main body having a driving portion driven by the power of the battery pack. is configured.

ADVANTAGE OF THE INVENTION According to this invention, the battery pack and electric equipment which suppressed the heat transfer of a battery cell can be provided. Also, it is possible to provide a battery pack and an electric device that suppress variation in temperature rise of battery cells. Further, by configuring the spaced portions formed in the plurality of insertion holes nonuniformly (asymmetrically), it is possible to adjust the heat transfer paths of the battery cells, and to make the heat transfer amount of the battery cells asymmetrical. In other words, since the heat transfer from the battery cell to the holder can be suppressed by the separating portion, heat transfer from the first insertion hole to the adjacent second insertion hole can be suppressed. Further, by adjusting the size (area) of the spaced portion in the circumferential and axial directions and the size of the radial gap (radial length), the temperature balance between the battery cells can be achieved. Furthermore, by forming the separating portion, the mass of the separator can be reduced, which contributes to the weight reduction of the battery pack.

1 is an overall view of an electric device 200 according to an embodiment of the invention; FIG. FIG. 2 is a perspective view of the battery pack 1 of FIG. 1; 3 is a perspective view of the battery pack 1 of FIG. 2 with an upper case 10, a right cover 4, and a left cover 6 removed; FIG. FIG. 4 is a perspective view of a state (holder set 40) in which a circuit board 30 is removed from the battery pack 1 in the state of FIG. 3; FIG. 5 is an exploded perspective view of the holder set 40 of FIG. 4; 6 is a perspective view of a single main holder 51 of FIG. 5. FIG. FIG. 2 is a cross-sectional view of the battery pack 1 of FIG. 1 taken along the left-right central vertical plane; FIG. 8 is a partial enlarged view of FIG. 7, (A) is a partial enlarged view near a battery cell 41, and (B) is a partial enlarged view near a concave portion 81 of (A). FIG. 8 is a partial longitudinal sectional view for explaining the state of heat conduction from the battery cells 41 to 43 of FIG. 7 to the main holder 51; FIG. 4 is a vertical cross-sectional view of a battery pack 301 according to a second embodiment of the invention; FIG. 10 is a vertical cross-sectional view of a battery pack 401 according to a third embodiment of the invention;

Embodiments of the present invention will be described below with reference to the drawings. In the drawings below, the same parts are denoted by the same reference numerals, and repeated descriptions are omitted. Further, in this specification, the front, back, left, right, and up and down directions are described as the directions shown in the drawings.

FIG. 1 is a perspective view of an electrical device 200 according to an embodiment of the invention. An electric device 200 is composed of an electric device main body 201 and a battery pack 1 attached thereto. Here, the electric device main body 201 is an example of an impact tool. The electric device main body 201 uses the detachable battery pack 1 as a power source, and uses the rotational driving force of the motor 204 as a drive unit to drive a tip tool (not shown) to perform tightening work. The electrical equipment main body 201 has a housing 202 which is an outer frame that forms an outer shape. A motor 204 is accommodated in a body portion 202a of the housing 202 at a position indicated by a dotted line, and a power transmission mechanism (not shown) is accommodated in front thereof, and an output shaft 208 of the power transmission mechanism protrudes forward from the housing 202. A handle portion 202b that is gripped by an operator extends downward from the body portion 202a, and a battery pack mounting portion 202c for mounting the battery pack 1 to the electric device main body 201 is formed below the handle portion 202b. be.

A trigger lever 206 for operating a trigger switch (not shown) protrudes from a portion of the handle portion 202b. The trigger switch is a variable switch for controlling on/off of rotation of the motor 204 and adjusting the rotation speed. A normal/reverse switching lever 207 for switching the rotation direction of the motor 204 is provided above the trigger lever 206 . A tip tool (not shown) such as a hexagonal socket is attached to the tip of the output shaft 208, and a rotary impact force is continuously or intermittently transmitted to the output shaft 208 to perform tightening operations such as nut tightening and bolt tightening.

The battery pack mounting portion 202c is formed with two rail portions (not visible in the figure) extending in parallel in the front-rear direction on the inner portions of the left and right side wall surfaces. no) is provided. The battery pack 1 accommodates a plurality of battery cells 41 to 50 (described later in FIG. 5) inside, and can output a DC rated voltage (for example, 18V or 36V). The output voltage of the battery pack 1 and the number and types of battery cells to be accommodated are arbitrary. The battery pack 1 can be attached to the battery pack attachment portion 202c by sliding it from the front side to the rear side of the electric device main body 201. As shown in FIG. When the battery pack 1 moves to a predetermined position in the mounting direction, a latch mechanism (not shown) operates to lock the battery pack 1 from the electric device main body 201 so that it does not come off. When removing the battery pack 1 from the electric device main body 201, the battery pack 1 is slid to the opposite side (forward side) to the mounting direction while pressing the latch buttons 16a (not visible in the drawing) and 16b provided on both left and right sides. After the battery pack 1 is removed from the electric device body 201, it can be charged using an external charger (not shown).

FIG. 2 is a perspective view of the battery pack 1. FIG. The battery pack 1 includes a holder group 40 that houses ten battery cells 41 to 50 (described later in FIG. 5), an upper case 10 that is attached to the upper side of the holder group 40, and a right side that is attached to the right side of the holder group 40. The appearance is determined by the cover 4 and the left cover 6 attached to the left side surface of the holder set 40 . The upper case 10, the holder set 40, the right cover 4, and the left cover 6 are each manufactured by molding non-conductive synthetic resin. Two groove-shaped rail portions 18a and 18b are formed in parallel on the front side surface of the lower stage surface 11 of the upper case 10 so as to extend in the front-rear direction. A slot group arrangement region 20 is arranged on the upper stage surface 13 sandwiched between the rail portions 18a and 18b. In the slot group arrangement area 20, eight slots (21, 22, 27, etc.) are arranged in the horizontal direction. These slots are formed so that connection terminals on the side of the electrical equipment main body 201 can be inserted. ) are formed with cutouts (openings), and the internal spaces of the cutouts can be fitted with device-side terminals of the electric device main body 201 or an external charging device (not shown). A plurality of connection terminals (battery pack side terminals) (described later with reference to FIG. 3) are provided.

Inside each slot, a positive electrode terminal for charging (C+ terminal), a positive electrode terminal for discharging (+ terminal), a spare slot, and an identification of the battery pack 1 are arranged in order from the left rail portion 18b of the battery pack 1 toward the right direction. A T terminal for outputting information signals to the main body of an electrical device or a charging device, a V terminal for inputting a control signal from an external charging device (not shown), an illustration provided in contact with a cell An LS terminal for outputting battery temperature information by a thermistor (temperature sensing element), a negative terminal (− terminal), and an LD terminal for outputting an abnormal stop signal by a battery protection circuit included in the battery pack 1 are arranged. .

At the front side of the battery pack 1, latch buttons 16a (not visible in the figure) and 16b for operating the latch mechanism are provided. When the latch button 16b is pushed, the engaging claw 17b moves inward in conjunction therewith, so that the engaging state between the engaging claw 17b and the concave portion (not shown) of the electric device main body 201 is released. Although not visible in FIG. 2, a similar latch button 16a and locking claw 17a are formed on the right side surface of the battery pack 1 as well. A stopper portion 15a recessed downward from the raised portion 15 is formed near the center between the latch buttons 16a and 16b. The stopper portion 15a abuts against a convex portion (not shown) of the electrical equipment main body 201 when the battery pack 1 is attached to the battery pack attachment portion 202c. When it is inserted until it abuts against, a plurality of connection terminals (apparatus-side terminals) provided on the electrical device main body 201 and a plurality of connection terminals 31 to 38 provided on the battery pack 1 (described later in FIG. 3) are in good contact with each other and become conductive.

A lower portion facing the opening surface 14 of the upper case 10 is formed by a holder set 40, a right cover 4 fixed on the right side, and a left cover 6 fixed on the left side. The left cover 6 is fixed to the holder set 40 with four screws 7a-7d. Although not visible in the drawing, the right cover 4 is bilaterally symmetrical with the left cover 6 and is fixed to the holder set 40 with four screws. The holder set 40 is formed with anti-slip processing 54c that is slightly recessed over the front wall surface, the bottom surface (not visible in the drawing), and the rear wall surface (not visible in the drawing). In the vicinity of the lower edge of the left cover 6, an anti-slip processed portion 6a having unevenness is formed. Although not visible in the drawing, a non-slip processed portion having unevenness is also formed in the vicinity of the lower edge of the right cover 4 . Here, the screws 7a and 7b are used to fix the left cover 6 and the upper case 10 to the holder set 40 by tightening them together. Similarly, the right cover 4 and the upper case 10 are also fixed to the holder set 40 by two screws provided at symmetrical positions to the screws 7a and 7b.

FIG. 3 is a perspective view of the battery pack 1 in the state of FIG. 2 with the upper case 10, the right cover 4 and the left cover 6 removed. Since the latch button 16b, the locking claw 17b, and other parts constituting the latch mechanism are formed inside the upper case 10, when the upper case 10 is removed, the circuit board 30 and the circuit board 30 are fixed to each other as shown in FIG. A plurality of connection terminal groups (31-32, 34-38) are exposed. The connection terminal group includes power terminals (positive terminals 31, 32, negative terminal 37) for transmitting power, and signal terminals 34 to 34 for transmitting signals to the electrical equipment main body 201 and an external charger (not shown). 36, 38) are provided. At the rear side of the connection terminal group (31-32, 34-38), synthetic resin for holding the legs of the connection terminals 31-32, 34-38 and insulating the circuit pattern on the circuit board 30 is provided. A terminal cover 39 is provided. The positive electrode terminals 31 and 32 and the negative electrode terminal 37 may be a battery pack in which two metal terminals are arranged so as to be slightly separated from each other in the vertical direction so that the voltage can be switched between high voltage and low voltage. A single-voltage battery pack having one each of the terminals 31 and 32 and the negative terminal 37 may be used. The present invention can be applied regardless of the type, number, arrangement position, etc. of the connection terminal group.

The holder set 40 is the remaining part after removing the connection terminal group and the circuit board 30 on which the electronic elements are mounted from the state of FIG. The holder set 40 includes ten battery cells 41 to 50, and a holder 100 (a main holder 51 and a main holder 51, which will be described later with reference to FIG. 5) formed so as to cover the entirety of them (except for the mounting portions of the connection tabs). It is an assembly of the holder cover 101). A holder (also referred to as a “separator”) used in a conventional battery pack is a supporting member for stacking the battery cells 41 to 50 at predetermined intervals. Therefore, basically, rather than dissipating heat in the holder, the design is based on the idea that the number of holding portions by the holder is reduced and the portions other than the holding portions are communicated with the space inside the case. Therefore, the conventional separator only partially holds the outer peripheral surfaces of the battery cells 41 to 50, and the entire assembly of the separator and the battery cells 41 to 50 is placed in a container-shaped lower case provided outside the separator. It was shaped so that everything could be stored in the internal space.

On the other hand, the holder of this embodiment covers the entire battery cells 41 to 50 and is integrally formed with the battery case and the outer case. (described later) also functions as a separator except for the left and right side surfaces of the lower case of a conventional battery pack.

The main holder 51 is basically formed mainly of a solid structure by integral molding of synthetic resin. In particular, about 70% of the portion (skeleton portion) near the center in the left-right direction is formed to have a thick band-shaped portion (base portion 54) so as to cover the outer sides of the front, lower, and rear sides of the battery cells. The thickness (for example, T ₁ , T ₂ ) until the base portion 54 is exposed to the outside is increased to enhance rigidity. Stepped surfaces 54b and 54c are formed on the front upper portion and the rear upper portion of the base portion 54, respectively. The stepped surfaces 54b and 54c are formed by a surface extending in the left-right direction and two surfaces extending in the front-rear direction from the ends in the left-right direction so that the stepped surfaces 54b and 54c are U-shaped when viewed from above. It becomes a joint surface with a part of the opening surface 14 of the upper case 10 (see FIG. 2). A mounting boss 55 is formed on the inner portion of the step surface 54b, and a mounting boss 56 is formed on the inner portion of the step surface 54c. The mounting bosses 55 and 56 are fixing portions for screwing the upper case 10, the right cover 4 and the left cover 6 shown in FIG. Screw holes 55b and 56b are formed on the left sides of the mounting bosses 55 and 56, respectively. Similarly, screw holes 55a and 56a (described later in FIG. 5) are formed on the right sides of the mounting bosses 55 and 56, respectively.

A plurality of through-holes 53a-53f are formed in the left wall surface 53 of the main holder 51 in order to wire the connection plates 91-96 to the battery cells 41-50. The through holes 53a to 53f are arranged so as to accommodate the connection plates 91 to 96, and allow the inside and outside of the main holder 51 to communicate with each other. Since it is preferable that the gap between the through holes 53a to 53f and the outer edge portions of the connection plates 91 to 96 is as small as possible, the outer edge shape of the through holes 53a to 53f is the same as the outer edge shape of the connection plates 91 to 96. It has a similar shape. The connection plate 91 is for extracting the positive electrode side output of the entire first battery cell group, and is connected to the positive electrode terminal of the battery cell 41 (refer to FIG. 5 described later for reference numerals). The connection plate 96 is for extracting the positive electrode side output of the entire second battery cell group, and is connected to the positive electrode terminal of the battery cell 45 (refer to FIG. 5 described later for reference numerals). The connection plates 91 and 96 are made of thin metal plates, and the connection tabs 91a and 96a are formed to extend upward from the welded portions with the battery cells 41 and 45. The end portions of 91a and 96a are arranged so as to pass through and are soldered on the upper surface of the circuit board 30. FIG. Notches 91b and 96b are formed in the vertical direction at the portions of the connection plates 91 and 96 that come into contact with the battery cells, respectively. 45 (see FIG. 5 for reference numerals). Providing the notches 91b and 96b between the spot-welded portions is a well-known technique in the battery pack 1, so detailed description thereof will be omitted.

The connection plates 92 to 95 are made of thin metal plates and are used for short-circuiting between two battery cells adjacent in the front-rear or oblique direction. Cutouts similar to the cutouts 91b and 96b are formed, and are connected to the positive electrode or the negative electrode of the battery cell by spot welding at a plurality of locations near the cutouts. Further, narrow plate-shaped connection tabs 92a, 93a, 94a, and 95a extending upward are integrally formed for measuring voltage between battery cells, and the connection tabs 92a to 95a extend upward from the lower surface of the circuit board 30. The ends of the connection tabs 92a to 95a are soldered to the circuit pattern on the upper surface of the circuit board 30 so that the ends of the connection tabs 92a to 95a pass through.

FIG. 4 is a perspective view of the battery pack 1 in the state of FIG. 3 with the circuit board 30 and the connection plates 91 to 96 removed (holder set 40). Through the through holes 53a to 53f formed in the left wall surface 53 of the main holder 51, the right end faces of the battery cells 41 to 50 are visible. The negative electrode side of each of the battery cells 41 to 50 has a flat shape, but the positive electrode side has a cylindrical projection coaxially with the central axis line. Please note that it is illustrated as Concave tab holding portions 58a to 58f for accommodating the connection tabs 91a to 96a are formed upward from the through holes 53a to 53f. , the connection plates 91 to 96 and the connection tabs 91a to 96a are arranged inside the leftmost end of the left wall surface 53 (in the direction close to the left-right center position). The tab holding portions 58a to 58f are concave portions recessed from the surface by partially thinning the thickness of the left side wall surface 53, and do not penetrate inside and outside.

FIG. 5 is an exploded perspective view of the holder set 40 of FIG. The holder set 40 is composed of two parts, a main holder 51 integrally molded of synthetic resin and a holder cover 101 covering an opening surface 60 located on the right side of the main holder 51 . An opening 60 is formed on the right side of the main holder 51 for inserting the battery cells 41-50. It is preferable not to form a through-hole for penetrating the inner space and the outer space in each of the wall surfaces of the upper wall surface 52a, the front wall surface 52b, the bottom surface 52c, and the rear wall surface 52d of the main holder 51. FIG. The opening surface 60 has a size sufficient to insert the battery cells 41 to 50, and has an opening surface 60 approximately equal in size to connecting the outer edges of the ten battery cells 41 to 50 together. The battery cells 41 to 50 are columnar lithium ion battery cells of so-called 18650 size, the central axis (for example, the dotted line 46a in the case of the battery cell 46) extends in the left-right direction, and the cross-sectional shape perpendicular to the central axis is It has a circular outer peripheral surface (46b for the battery cell 46, for example). Ten battery cells 41 to 50 are inserted into the opening surface 60 from right to left. A plurality of independent insertion holes 61-70 are formed for inserting the battery cells 41-50 and covering the entire length of the outer peripheral surface of each battery cell 41-50 in the axial direction. Each of the insertion holes 61-70 is formed to have the same length L as the battery cells 41-50 in the direction of the central axis (eg 46a). After the battery cells 41-50 are respectively inserted into the insertion holes 61-70, the outer peripheral surfaces of the battery cells 41-50 do not contact each other. The opening surface 60 is closed by being covered with a holder cover 101 from the right side. The main holder 51 and the holder cover 101 do not need to be firmly fixed by adhesion or the like, but they may be firmly fixed.

A mounting boss 55 is formed at the front upper corner of the main holder 51 . A screw hole 55a is formed on the right side of the mounting boss 55, and a screw hole 55b (see FIG. 3) is formed on the left side. A mounting boss 56 is formed at the rear upper corner of the main holder 51 . A screw hole 56a is formed on the right side of the mounting boss 56, and a screw hole 56b (see FIG. 3) is formed on the left side. A support portion 57b for holding the circuit board 30 is formed on the front side of the mounting boss 56, and a screw boss 57a for fixing the circuit board 30 is formed on the front side.

The holder cover 101 serves as a cover that covers the opening surface 60 formed on the right side of the main holder 51, and covers and holds the right ends of the battery cells 41-50. In the outer edge portion of the holder cover 101, an upper edge portion 102a, a front edge portion 102b, a lower edge portion 102c, and a rear edge portion 102d are formed along the contour shape of the opening surface 60, and are in good contact with the opening surface 60. Improves water and dust resistance. Separation projections 103 to 106 having a substantially diamond-shaped outer edge are formed inside the holder cover 101 to prevent the holder cover 101 from being displaced in the front-rear and up-down directions. The separation projections 103 to 106 are solid portions having a length of about L/2 in the direction of the central axis 46a and formed to fill the space between four adjacent cells. A concave portion 81 a is formed in the separation protrusion 103 . Although not visible in the drawing, recesses similar to the recesses 81a are similarly formed on part of the outer surfaces of the separation projections 104 to 106 as well. The shape of this recess will be described later with reference to FIG.

A plurality of through holes 111 to 116 are formed in the right side surface of the holder cover 101 . Through holes 111 to 116 are for accommodating connection plates (not shown) that connect adjacent battery cells. The through holes 111 to 116 are formed in a similar shape to the outer edge portion of the connection plate (not shown), similarly to the left wall surface 53 of the main holder 51, and are also formed with recesses for accommodating connection tabs for drawers. . The output of the connection plate arranged in the through hole 113 is for extracting the negative electrode side output of the entire first battery cell group. The output of the connection plate arranged in the through hole 115 is for extracting the negative electrode side output of the entire second battery cell group. Although not shown, the through holes 111 to 116 accommodate connection plates (not shown) made of thin metal plates similar to the connection plates 91 to 96 shown in FIG. A connection plate (not shown) has cutouts similar to the cutouts 91b and 96b shown in FIG. The connection plate (not shown) and the battery cells 41 to 50 are fixed by the .

FIG. 6 is a perspective view showing the single main holder 51 of FIG. 5, viewed from a slightly shifted position. The main holder 51 is formed with insertion holes 61 to 70 that come into contact with the outer peripheral surfaces of the battery cells 41 to 50 . It is formed by projections 104-106. Accordingly, the main holder 51 is formed with depressions 77 to 80 having substantially rhombic cross-sectional outer edge shapes, which are depressed from the right side surface toward the left side, in order to accommodate the separation protrusions 104 to 106 . Separation projection 103 (see FIG. 5) corresponds to depression 77 , separation projection 104 (see FIG. 5 ) corresponds to depression 78 , separation projection 105 (see FIG. 5 ) corresponds to depression 79 , and depression 80 . corresponds to the separation protrusion 106 (see FIG. 5).

The recesses 77, 80 are formed with a solid inside, and the recesses 78, 79 are formed with a hollow inside. The reason why the insides of the recesses 78 and 79 are hollow is that it is easier to mold when they are hollow for the convenience of synthetic resin injection molding, and also for weight reduction. It is optional whether any one of the recesses 77-80 is formed hollow or solid. In the facing parts, there is a part that is in close contact (a part that contacts so as to sufficiently transfer heat) and a part that has a gap in the radial direction (a gap is formed without contact to block heat as much as possible). part). Concave portions 81 to 89 are formed as portions (clearance portions) having clearances in the radial direction. The inner peripheral surfaces (inner surfaces) of the insertion holes 61 to 70 correspond to the "opposing surfaces" of the present invention.

FIG. 7 is a cross-sectional view of the battery pack 1 taken along the left-right central vertical plane. The holder cover 101 is not shown in FIG. 7 because the holder cover 101 does not reach the right-left center vertical plane. A portion around the battery cells 41 to 50 is a portion formed by the main holder 51 . The main holder 51 of the present embodiment is molded in a solid shape except for hollow portions such as hollow portions 54d and 54e which are necessary for injection molding of synthetic resin. The circular cross-sectional shape of the insertion holes 61-70 is formed so that the cross-sections of the battery cells 41-50 are in good contact with the circular outer peripheral surface. Here, “close contact” means a contact state in which good heat conduction is performed from the contact portion of the battery cells 41 to 50 to the contact portion of the main holder 51, or the contact state in which the battery cells 41 to 50 are in the insertion holes 61 to 70. It is a contact state that is sufficiently held so as not to physically move in the left and right direction. A part of the inner surface of the insertion holes 61-70 is provided with recesses 81-89 for positively spacing the insertion holes 61-70 from the outer peripheral surfaces of the battery cells 41-50 to form predetermined gaps. Insertion holes 61, 65, 67-69 in which only one concave portion 81, 82, 85-87 is formed are the "first insertion holes" of the present invention in which one gap is formed between the outer peripheral surface of the battery cell. Equivalent to Of the inner peripheral surfaces of the insertion holes 61 to 79, the concave portion corresponds to the "separation portion" of the present invention, and the portion other than the concave portion that contacts (closely contacts) the battery cell corresponds to the "contact portion" of the present invention.

As can be seen in FIG. 7, recesses 81-89 are not formed in all insertion holes 61-70, but none are formed in insertion holes 62-64. The insertion holes 62 to 64 in which the concave portions 81 to 89 are not formed correspond to the "second insertion holes" of the present invention in which no gap is formed between them and the outer peripheral surface of the battery cell. Two recesses 83 and 84 are formed in the insertion hole 66 , and two recesses 88 and 89 are formed in the insertion hole 70 . The insertion hole 66 having a plurality of recesses 83 and 84 and the insertion hole 70 having a plurality of recesses 88 and 89 form the "third insertion hole" of the present invention in which a plurality of gaps are formed between the outer peripheral surface of the battery cell. Corresponds to "hole". In the "third insertion hole", recesses 83, 84 are adjacent to at least one of the first insertion hole and the second insertion hole (here, the first insertion hole) and are located at positions corresponding to the positions of the adjacent first insertion holes. , 88 and 89 are provided.

The recesses 81-89 are continuously formed in the left-right direction so as to have the same cross-sectional shape from the left end position to the right end position of the insertion holes 61, 65-70. In addition, the respective insertion holes 61, 65, 66 to 70 are not the same in the positions where the recesses are formed when viewed in the circumferential direction of the cross section. The insertion hole 61 has a recessed portion 81 formed at a side surface position close to the battery cell 42 (in terms of clockwise rotation angle, the range is 70° to 110° when 0° is the upward direction). The insertion hole 65 has a recess 82 formed at a side surface position (in the range of 250° to 290°) near the battery cell 44 . The insertion holes 66-70 are formed with recesses 83, 85-88 at side positions (in the range of 330°-40°) near the upper battery cells 41-45. Further, the insertion hole 66 is also formed with a concave portion 84 at a side position (range of 55° to 125°) near the battery cell 47, and the insertion hole 70 is formed at a side position (between 235° and 305°) near the battery cell 49. A recessed portion 89 is also formed in the range).

The recesses 81-89 are formed to adjust the heat conduction from the battery cells 41, 45-50 to the main holder 51 and the holder cover 101. As shown in FIG. For example, the main holder 51 and the holder cover 101 can be made of synthetic resin such as PC (polycarbonate) or PA (polyamide). Normally, the battery cells 41 to 50 may generate heat during charging and discharging, and the amount of heat generated increases as the current value increases. The heat generated in the battery cells 41 to 50 of this embodiment is transmitted from the outer cylindrical surfaces of the battery cells 41 to 50 to the wall surfaces of the insertion holes 61 to 70 of the main holder 51 or the holder cover 101, and the main holder 51 and the holder cover. Battery cells 41 to 50 are cooled by radiating heat from 101 to the atmosphere. Although there is also heat conduction from the end faces (positive electrode position, negative electrode position) that are perpendicular to the central axis of the battery cells 41 to 50, here, to simplify the explanation, heat is conducted from the outer peripheral surfaces of the battery cells 41 to 50. will be described with a focus on heat conduction.

In the battery pack 1 having ten battery cells 41 to 50 as in the present embodiment, heat dissipation from the battery cells near the central region of the battery pack 1 is the most severe. It is larger than the battery cells 41 and 45-50. Here, the “central region” is the range occupied by the battery cells 43 located at half the height H of the battery pack 1 and half the total length (front-rear length) L of the battery pack. , and the space of the insertion hole 63 in which the battery cell 43 is accommodated. In this embodiment, the concave portions 81 to 89 are formed so as to be recessed from the battery cell side farther from the central region toward the battery cell side closer to the central region among the adjacent battery cells 41 to 50 . That is, the recess 81 of the insertion hole 61 is formed on the side of the battery cell 42 having a higher temperature than the battery cell 41 inserted into the insertion hole 61 . Further, the recess 82 of the insertion hole 65 is formed on the side of the battery cell 44 having a higher temperature than the battery cell 45 inserted into the insertion hole 65 . In this way, the portion of the holder 100 (51, 101) that separates the adjacent battery cells receives more heat from the battery cells closer to the central region, thereby balancing the temperature of the battery cells. As a result, the closer to the central region, the less heat escapes (the less heat is transmitted), and the state in which the temperature of the battery cells 42 to 44 rises can be suppressed.

When stacking battery cells 41 to 45 on the upper side and battery cells 46 to 50 on the lower side in two stages, the battery cell 43 is located on the upper side and in the center in the front-rear direction. The space occupied by is the central region, and the insertion hole 63 is the centrally positioned insertion hole. In this case, the upper battery cells 41-45 have a greater distance to the outside of the battery pack 1 (outside air) than the distance from the battery cells 46-50. Therefore, it becomes a severe condition for heat dissipation. Accordingly, concave portions 83 and 85-88 are formed in portions of the insertion holes 66-70 that accommodate the lower battery cells 46-50 and adjacent to the upper battery cells 41-45. Furthermore, recesses 84 and 89 are provided in the insertion holes 66 and 70 on the sides adjacent to the battery cells 47 and 49 which reach a higher temperature. Since the battery cells 46 and 50 are arranged on the bottom side of the battery pack 1 and at the extreme end in the front-rear direction, the battery cells 41 to 50 are the least likely to generate heat. Therefore, heat transfer from the battery cells 46 and 50 to the holder 100 (adjacent battery cells) is suppressed by providing a plurality of recesses in one insertion hole.

Next, the shapes and effects of the recesses 81 to 89 formed in the insertion holes 61 and 65 to 70 will be described. 8 is a partially enlarged view of FIG. 7, and (A) is a partially enlarged view of the vicinity of the battery cell 41. FIG. A recess 81 is formed in the insertion hole 61 that accommodates the battery cell 41 . The recessed portion 81 is a portion formed so as to be recessed radially outward from the outer peripheral surface of the battery cell 41, and the main holder 51 and the battery cell 41 are not in contact with each other in the portion (region) where the recessed portion 81 is formed. A gap will be formed. Since air exists in the gaps formed by the recesses 81 , heat conduction in the recesses 81 is caused by the contact between the heat-generating battery cells 41 and the recesses 81 of the main holder 51 via the air layer formed by the recesses 81 . This is done in the direction of the solid partition wall 98a. The partition wall 98 a corresponds to a “connecting portion” that connects the insertion holes 61 and 62 . The degree of heat transfer to the partition wall 98a in contact with the recess 81 of the main holder 51 is affected by the area occupied by the recess 81 (the circumferential length S ₁ , the radial depth S ₂ and the axial length S ₃ ). .

FIG. 8(B) is a partially enlarged view of the vicinity of the concave portion 81 in (A). Here, the distance between the battery cells 41 and 42 near the partition wall 98a is T when the recess 81 is not formed, and the depth S ₂ (length in the radial direction) of the recess 81 is 1/1 of T. 2 or less, and here, _S2 is about 20% of T. If the depth _S2 is too large, the strength near the partition wall 98a will be reduced. Moreover, if the depth _S2 is set to 1/2 or more of T, the temperature rise of the battery cells 42 near the central region is rather high, so the thickness of the partition wall 98a should be more than half of the original distance T. good to do The degree of heat conduction from the battery cell 41 to the vicinity of the partition wall 98a can also be adjusted by the circumferential length _S1 and the axial length _S3 (not shown) of the battery cell. The axial length _S3 of the concave portions 81 to 89 in FIG. 7 is formed equal to the axial length L of the battery cells 41 to 50 (see FIG. 5).

FIG. 9 is an image diagram for explaining the state of heat conduction from the battery cells 41 to 43 to the main holder 51. As shown in FIG. Here, the state of heat conduction to the partition walls 98a and 98b of the main holder 51 in the battery cells 41 to 43 is indicated by a large number of black arrows. Here, short black arrows indicate small heat conduction, and long arrows indicate large heat conduction (however, these are rough images, not exact sizes). As for heat transfer from the battery cell 41 to the partition wall 98a, the amount of heat transfer is small in the portion where the recess 81 is formed, and the amount of heat transfer is large in the portion where the outer peripheral surface of the battery cell 41 is in contact with the partition wall 98a. The amount of heat transferred from the battery cell 42 to the partition wall 98a is substantially uniform because the entire outer peripheral surface of the battery cell 42 is in contact with the partition wall 98a. As can be understood here, the amount of heat transfer from the battery cell 41 to the partition wall 98a is smaller than the amount of heat transfer from the battery cell 42 to the partition wall 98a due to the provision of the air layer by the recess 81. . As a result, while suppressing heat transfer from the battery cell 41 to the partition wall 98a in the direction in which the battery cell 42 is located, heat dissipation from the battery cell 42 to the partition wall 98a proceeds, and the recess 81 is not formed. Temperature rise of the battery cell 42 is suppressed more than the holder.

As described above, heat radiation from the battery cell 41 is partially hindered by the provision of the recess 81. Since it is close to the outside of the battery pack 1 , it is cooled by outside air more than the battery cell 42 . By adjusting the position, size, and number of recesses according to the position of the battery cell in the main holder 51, the heat dissipation balance between adjacent battery cells (battery cell 41 and battery cell 42) can be achieved. it is possible to take.

An air layer is not formed by the concave portion in the insertion hole 62 that accommodates the battery cell 42 . Similarly, an air layer is not formed by recesses in the insertion holes 63 that accommodate the battery cells 43 . Therefore, in the vicinity of the partition wall 98b between the battery cells 42 and 43, there is almost even heat conduction from the battery cells 42 and 43 before and after as indicated by a plurality of black arrows. Although local heat conduction near the partition walls 98a and 98b has been described in FIG. Needless to say.

As described above with respect to the embodiments of the present invention, the holder 100 (main holder 51, holder cover 101) allows substantially the entire outer peripheral surface portions and end surface portions (positive electrode and negative electrode portions) of a plurality of battery cells (connection plate 91) to be connected. 96, etc.). In order to adjust the degree of heat conduction from each of the battery cells 41 to 50 to the holder 100 (main holder 51, holder cover 101), gaps are formed by the concave portions 81 to 89 to form an air layer. In this way, variations in the degree of heat rise of the battery cells 41 to 50 are suppressed. In particular, the gaps formed by the recesses 81-89 are formed on the inner peripheral surfaces of the insertion holes 61-70, and the gaps do not come into contact with the outside air. In addition, since the recesses 81 to 89 can be easily manufactured in a part of the holder 100 (main holder 51, holder cover 101) by injection molding of synthetic resin, the increase in manufacturing cost is small. Further, by adjusting the positions of the concave portions 81 to 89, the width of the opening surface of the concave portions, and the depth of the concave portions, it is possible to freely adjust the temperature balance of the battery cells 41 to 50. FIG. In the first embodiment, the present invention was explained using the battery pack 1 containing ten battery cells. However, the number of battery cells accommodated in the battery pack is not limited to 10, and the present invention can be similarly applied to a battery pack using a holder in which two or more cells are arranged.

FIG. 10 is a longitudinal sectional view of a battery pack 301 according to a second embodiment of the invention. The battery pack 301 includes an upper case 10, a lower case 320, 15 battery cells 341-355, and a separator (holder) 360 that accommodates the battery cells 341-355. Here, the circuit board 30 (see FIG. 7) attached to the upper side of the separator 360, the latch mechanism, the guide rail mechanism, the connection terminals 31, 32, 34 to 38, etc. have the same or substantially the same configuration as in the first embodiment. can be Unlike the holder 100 (main holder 51 and holder cover 101) of the first embodiment, the separator 360 is not manufactured as a part of the housing which itself is exposed to the outside air, but is commercially available. It is positioned inside a housing called a lower case 320, like a known battery pack.

The separator 360 accommodates a total of 15 battery cells 341 to 355, 3 in the vertical direction and 5 in the front-rear direction, which enables stacking of so-called 3 rows and 5 rows. The battery cells 341 to 355 are so-called 18650-size lithium-ion battery cells, but the size of the battery cells is arbitrary. good. The outer shape of the battery pack 301 has a height H ₁ and a depth (longitudinal length) D ₁ , and the middle position of the height H ₁ direction and the middle position of the depth D ₁ are drawn by dotted lines as shown in FIG. 10 . The intersection of these horizontally and vertically extending dotted lines 304 and 305 is the center position, and the insertion hole 368 of the battery cell 348 located at the center position is the center region of the battery pack 301 . Of the insertion holes 361 to 375 of the battery cells 341 to 355, the battery cell 348 located in the central region and the insertion holes 367 to 369 for accommodating the battery cells 347 and 349 located on both front and rear sides thereof are not formed with concave portions. On the other hand, one or two recesses 381 to 396 are formed in the other insertion holes 361 to 366 and 370 to 375, respectively.

In the upper insertion holes 362 to 364, there are three insertion holes 367 to 369 for battery cells 347 and 349 which are sandwiched by other battery cells adjacent to the battery cell 348 in the center area and vertically and horizontally adjacent to it. , recesses 383 to 385 are formed. A recess 381 is formed in the insertion hole 361 on the side closer to the battery cell 342 , and a recess 382 is formed on the side closer to the battery cell 346 . Similarly, in the insertion hole 365 , a recess 386 is formed on the side closer to the battery cell 344 and a recess 387 is formed on the side closer to the battery cell 350 . The middle insertion hole 366 is formed with a recess 388 near the three insertion holes 367-369, and the insertion hole 370 is formed with a recess 389 near the three insertion holes 367-369.

Recesses 392 to 364 are formed in the lower insertion holes 372 to 374 on the side near the three insertion holes 367 to 369, respectively. A recess 391 is formed in the insertion hole 371 on the side closer to the battery cell 352 , and a recess 390 is formed on the side closer to the battery cell 346 . Similarly, the insertion hole 375 has a recess 396 formed on the side closer to the battery cell 354 and a recess 395 formed on the side closer to the battery cell 350 .

As described above, among the insertion holes 361 to 375 of the separator 360, the first insertion holes (here, the insertion holes 362 to 364, 366, 370, 372 to 374) and the second insertion hole (insertion holes 367 to 369 here) in which no gap is formed between the outer peripheral surface of the battery cell and the spaced portion (recess) between the outer peripheral surface of the battery cell Since the third insertion holes (here, insertion holes 361, 365, 371, 375) having a plurality (two) of It is possible to adjust the temperature transfer situation to.

FIG. 11 is a longitudinal sectional view of a battery pack 401 according to a third embodiment of the invention. The battery pack 401 includes an upper case 410, a holder (separator) 450 serving as a lower case, and five battery cells 441-445. The holder 450 is formed with five battery cell insertion holes 461-465 for accommodating the battery cells 441-445. Here, illustration of a circuit board, a latch mechanism, a guide rail mechanism, connection terminals, etc., which are attached to the upper side of the holder 450 is omitted. As with the holder 100 (main holder 51 and holder cover 101) of the first embodiment, the holder 450 is mounted so as to expose itself to the outside air, and forms part of the housing.

The holder 450 has two stages in the vertical direction, three in the upper stage in the front-rear direction and two in the lower stage in the front-rear direction to accommodate a total of five battery cells 441-445. When viewed in the front-rear direction, the center axes of the battery cells 444 and 445 are positioned between the battery cells 441 and 442 and between the battery cells 442 and 443 respectively. Form 465. Here, the battery cell 442 is positioned in the central region where the center line 404 in the height _H2 direction of the battery pack 401 and the center line 405 in the depth direction (front-rear direction) _D2 intersect. Therefore, the insertion hole 462 for the thermally severe battery cell 442 corresponds to the “second insertion hole” in which no gap is formed between the outer peripheral surface of the battery cell 442 and the battery cell 442 . The remaining insertion holes 461, 463-465 correspond to "first insertion holes" having only one spaced portion (recess) between the outer peripheral surfaces of the battery cells 441, 443-445. In a battery pack 401 that accommodates only five battery cells 441 to 445, a "third insertion hole" having a plurality of spaced portions (concave portions) between the outer peripheral surfaces of the battery cells is not formed.

According to the present invention described above, in a battery pack in which a plurality of battery cells are entirely covered with a holder (separator), the insertion holes for the plurality of battery cells are independently formed in a cylindrical shape, and the battery cells are inserted into the battery pack. The basic configuration is such that the battery cell is in contact with the entire outer peripheral surface, and one or more gaps (spaced portions) are formed between some of the plurality of insertion holes and the outer peripheral surface of the battery cell. By forming the gaps (spaced portions) non-uniformly (asymmetrically), it has become possible to adjust the path of heat transfer from the battery cell to the holder. In addition, by adjusting not only the number of gaps (spaced parts), but also the sizes (areas) occupied in the circumferential and axial directions, and the sizes of radial gaps (radial length), You can adjust the temperature balance. It should be noted that the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. For example, in the above-described embodiment, an example using a cylindrical battery cell was described, but a battery cell having a rectangular parallelepiped shape or other shape may be used to form an insertion hole having a space having a shape similar to the outer shape of the battery cell. Alternatively, a recessed gap (spaced portion) may be formed in a part of the insertion hole.

1 battery pack 4 right cover 6 left cover 6a non-slip processed parts 7a to 7d screws 10 upper case 11 lower stage surface 12 stepped surface 13 upper stage surface 14 opening surface 15 raised portion 15a stopper portions 16a, 16b latch buttons 17a, 17b locking claws 18a, 18b rail portion 20 slot group arrangement area 21-28 slot 30 circuit board 31, 32 positive terminal 34-36 signal terminal 37 negative terminal 38 signal terminal 39 terminal cover 40 holder set 41-50 battery cell 46a ) Central axis 46b (of battery cell 46) outer peripheral surface 51 main holder 52a upper wall surface 52b front wall surface 52c bottom surface 52d rear wall surface 53 left wall surface 53a to 53f through hole 54 base portion 54a, 54b stepped surface 54c non-slip processing 54d, 54e Cavity portions 55, 56 Mounting bosses 55a, 55b, 56a, 56b Screw hole 57a Screw boss 57b Supporting portion 58a-58f Tab holding portion 60 Opening surfaces 61-70 Insertion hole 81-89 Recess (gap) 81a Recess (gap)
91-96 Connection plate 91a-96a Connection tab 91b, 96b Notch 91c, 96c Spot weld 98a, 98b Partition wall 100 Holder 101 Holder cover 102a Upper edge 102b Front edge 102c Lower edge 102d Rear edge 103-106 Separation Protrusions 111-116 Through Hole 200 Electrical Device 201 Electrical Device Body 202 Housing 202a Body 202b Handle 202c Battery Pack Mounting Portion 204 Motor 206 Trigger Lever 207 Forward/Reverse Switching Lever 208 Output Shaft 301 Battery Pack 320 Lower Case 341-355 Battery cell 360 Separator 361-375 Insertion hole 381-396 Recess 401 Battery pack 410 Upper case 441-445 Battery cell 450 Holder 461-465 Insertion hole

Claims (12)

a plurality of battery cells;
a separator that has a plurality of insertion holes into which each of the plurality of battery cells is inserted and that supports the plurality of battery cells;
A battery pack comprising
each of the plurality of insertion holes has a facing surface facing the outer peripheral surface of the battery cell,
The facing surface of the first insertion hole among the plurality of insertion holes includes a contact portion that contacts the outer peripheral surface of the battery cell, and a separation portion in which a gap is formed between the outer peripheral surface of the battery cell; has
The separation portion is provided asymmetrically in the vertical direction or asymmetrically in the horizontal direction with respect to the axis of the battery cell,
A battery pack characterized by: a plurality of battery cells;
a separator that has a plurality of insertion holes into which each of the plurality of battery cells is inserted and that supports the plurality of battery cells;
A battery pack comprising
each of the plurality of insertion holes has a facing surface facing the outer peripheral surface of the battery cell,
The plurality of insertion holes include a first insertion hole having a contact portion that contacts the outer peripheral surface of the battery cell and a separation portion that forms a gap between the outer peripheral surface of the battery cell, and the contact portion. a second insertion hole that has only the spaced portion and does not have the spaced portion;
A battery pack characterized by: The battery pack according to claim 1 or 2,
The plurality of insertion holes have a second insertion hole adjacent to the first insertion hole,
The separating portion is provided on a side of the first insertion hole on which the second insertion hole is provided,
A battery pack characterized by: The battery pack according to claim 3,
A battery pack according to claim 1, wherein the battery cell inserted into the second insertion hole has a lower temperature rise than the battery cell inserted into the first insertion hole. The battery pack according to any one of claims 2 to 4,
the plurality of insertion holes have a third insertion hole adjacent to at least one of the first insertion hole and the second insertion hole and having the contact portion and the separation portion;
A battery pack, wherein the first insertion hole and the third insertion hole are different in size from each other. The battery pack according to claim 5,
The battery pack, wherein the spaced portions of the first insertion hole and the third insertion hole have different lengths in the circumferential direction of the battery cell. The battery pack according to claim 5 or 6,
The battery pack, wherein the separation portion between the first insertion hole and the third insertion hole has a different distance between the battery cell and the facing surface. The battery pack according to any one of claims 1 to 7,
The plurality of insertion holes have a second insertion hole adjacent to the first insertion hole,
the separator has a connecting portion that connects the first insertion hole and the second insertion hole in a direction in which the first insertion hole and the second insertion hole are arranged;
the dimension of the gap in the spacing portion in the arranging direction is smaller than the dimension of the connecting portion;
A battery pack characterized by: The battery pack according to claim 8,
The battery pack, wherein the second insertion hole is provided in a central region of the separator. a plurality of battery cells;
a separator that has a plurality of insertion holes into which each of the plurality of battery cells is inserted and that supports the plurality of battery cells;
A battery pack comprising
At least three of the plurality of insertion holes are arranged side by side in the front-rear direction,
Of the plurality of insertion holes, the insertion holes other than the insertion hole positioned at the center are separated portions in which a gap is formed between a contact portion that contacts the outer peripheral surface of the battery cell and the outer peripheral surface of the battery cell. and having
A battery pack characterized by: The battery pack according to claim 9,
The separation part is provided on the side where the insertion hole located in the center is provided,
A battery pack characterized by: a battery pack according to any one of claims 1 to 11;
an electric device main body having a battery pack mounting portion to which the battery pack is mounted; and a driving portion driven by the power of the battery pack;
An electrical device comprising:

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