JP6062646B2 - Battery pack - Google Patents

Description

  The present invention relates to a battery pack having a plurality of unit cells, and more particularly to a connection structure between a unit cell and a circuit board.

In recent years, a battery pack including a plurality of unit cells has been widely used as a power source for notebook personal computers or the like (see Patent Documents 1 and 2).
Here, the unit cell includes a flat rectangular outer package, and a positive electrode terminal and a negative electrode terminal extending from one end surface of the outer package in one direction orthogonal to the thickness direction. A battery core in which the positive and negative terminals of each unit cell are connected to the circuit board in a state where a plurality of unit cells are arranged in a direction perpendicular to the extending direction of the positive and negative terminals is housed in the case. By doing so, the battery pack is manufactured. Here, the circuit board means a board provided with conductive lands electrically connected to the positive terminal and the negative terminal.

FIG. 16 shows a perspective view of a battery core constituting a part of this type of battery pack.
As shown in FIG. 16, the battery core 1010 includes three unit cells 1011, 1021, 1031 and a circuit board 1071. Here, the unit cells 1011, 1021, 1031 have the positive terminals 1011 a, 1021 a, 1031 a and the negative terminals 1011 b, 1021 b, 1031 b protrude in the same direction, and the positive terminals 1011 a, 1021 a, 1031 a and negative terminals 1011 b, 1021 b , 1031b are arranged in a direction orthogonal to the protruding direction. The circuit board 1071 is arranged along the arrangement direction of the unit cells 1011, 1021, and 1031. In the circuit board 1071, conductive lands 1072a, 1072b, 1073a, 1073b, 1074a, 1074b to which the positive terminals 1011a, 1021a, 1031a and the negative terminals 1011b, 1021b, 1031b are respectively connected are unit cells 1011, 1021, 1031. Are arranged in a row along the arrangement direction.

JP 2002-117828 A JP 2008-41292 A

  However, in the battery core 1010 having the configuration shown in FIG. 16, the conductive lands 1072a, 1072b, 1073a, 1073b, and 1074a are located in the circuit board 1071 at positions corresponding to the positive terminals 1011a, 1021a, and 1031a and the negative terminals 1011b, 1021b, and 1031b, respectively. , 1074b need to be formed, and the length L1001 in the arrangement direction of the unit cells 1011, 1021, 1031 of the circuit board 1071 becomes longer. Thus, when the circuit board 1071 is elongated, the housing for housing the battery core 1010 must be enlarged accordingly, and the battery pack may not be reduced in size.

  This invention is made | formed in view of the said reason, and it aims at providing the battery pack which can achieve size reduction.

  The battery pack according to the present invention includes an exterior body, a plurality of unit cells having a plate-like positive electrode terminal and a negative electrode terminal protruding in the same direction from the exterior body, and a plurality of conductive lands corresponding to the plurality of unit cells, respectively. In addition, in the plurality of unit cells, the circuit board is disposed close to the end face from which the positive electrode terminal and the negative electrode terminal protrude, and is disposed between the end surface of the plurality of unit cells and the circuit board, and is electrically connected to the positive electrode terminal and the negative electrode terminal. A plurality of lead cells that are electrically connected to the lands, and the plurality of unit cells are arranged in a direction intersecting a protruding direction of the positive electrode terminal and the negative electrode terminal, and a plurality of conductive cells are arranged in the arrangement direction of the plurality of unit cells. The entire length of the conductive land group consisting of lands is shorter than the total length of the terminal group consisting of a plurality of positive and negative terminals.

  According to this configuration, in the arrangement direction of the plurality of unit cells, the entire length of the conductive land group including the plurality of conductive lands is shorter than the total length of the terminal group including the plurality of positive and negative terminals. Thus, in the arrangement direction of the plurality of unit cells, the conductive lands are arranged in a concentrated manner in a region shorter than the entire length of the plurality of unit cells in the circuit substrate, thereby reducing the length of the circuit board. The overall length of the plurality of unit cells can be made shorter, and the size of the circuit board can be reduced. Thus, the battery pack can be reduced in size by the amount that the size of the circuit board can be reduced.

It is a disassembled perspective view of the battery pack which concerns on embodiment. It is a perspective view of the battery core which concerns on embodiment. The unit cell which concerns on embodiment is shown, (a) is the side view seen from one direction, (b) is the side view seen from the A1 direction in (a). It is a figure which shows the circuit structure of the battery pack which concerns on embodiment. The lead board laminated structure which concerns on embodiment is shown, (a) is a disassembled perspective view, (b) is a perspective view. The lead board laminated structure which concerns on embodiment is shown, (a) is a top view, (b) is sectional drawing fractured | ruptured by the AA line in (a) and seen from the arrow direction. It is a figure for demonstrating the manufacturing method of the battery pack which concerns on embodiment. It is a figure for demonstrating the manufacturing method of the battery pack which concerns on embodiment. It is a figure for demonstrating the manufacturing method of the battery pack which concerns on embodiment. It is a figure for demonstrating the manufacturing method of the battery pack which concerns on embodiment. It is a figure for demonstrating the manufacturing method of the battery pack which concerns on embodiment. It is a figure for demonstrating the manufacturing method of the lead board laminated structure which concerns on embodiment. The lead board laminated structure which concerns on a modification is shown, (a) is a disassembled perspective view, (b) is a perspective view. It is a perspective view of the battery core which concerns on a modification. The lead board laminated structure which concerns on a modification is shown, (a) is a disassembled perspective view, (b) is a perspective view. It is a perspective view of the battery core which concerns on a prior art example.

<Embodiment>
<1> Configuration A configuration of the battery pack 1 according to the present embodiment will be described.
An exploded perspective view of the battery pack 1 is shown in FIG. 1, and a perspective view of the battery core 10 is shown in FIG.
The battery pack 1 includes a battery core 10 and a case 102 that houses the battery core 10.

  The battery core electrically connects the unit cell group including a plurality (three in FIG. 1) unit cells 11, 21, 31, the circuit board 71, the unit cells 11, 21, 31 and the circuit board 71. Lead plate laminated structure 101 and an external connector 81 attached to a circuit board 71 via lead wires 83. Further, protective elements 13, 23, 33 for protecting the circuit board 71 are attached to the respective unit cells 11, 21, 31. The thermistors 19 and 29 for detecting the temperature in the battery pack 1 are attached to the unit cells 11 and 21.

<1-1> Case The case 102 includes a case member 3, exterior labels 5 and 7 that cover the case member 3, and an insulating sheet 9.
The case member 3 includes a main body 3a having a substantially rectangular frame shape, and a protrusion 3b that protrudes outward from a part of the main body 3a and has a recess 3c formed on the other surface side of the case member 3. Here, in the case member 3, the battery core is placed in a state where the three unit cells 11, 21, 31 are located inside the main body 3 a and the circuit board 71 is located inside the recess 3 c of the protruding portion 3 b. 10 is arranged. Then, with the battery core 10 disposed inside the case member 3, the exterior label 5 is attached to one surface side of the case member 3, and the inside of the main body 3 a is disposed on the other surface side of the case member 3. An exterior label 7 is attached so as to cover, and an insulating sheet 9 is attached so as to cover the recess 3c formed in the protruding portion 3b.

<1-2> Unit Cell FIG. 3A shows a side view of the unit cell 11 viewed from one direction, and FIG. 3B shows a side view seen from the A1 direction in FIG. In addition, since the structure of the unit cells 21 and 31 is the same as that of the unit cell 11, description is abbreviate | omitted.
The unit cell 11 includes a flat rectangular parallelepiped exterior body 11c, and plate-like positive electrode terminals 11a and negative electrode terminals 11b that protrude from one end surface in the longitudinal direction of the exterior body 11c in the longitudinal direction of the exterior body 11c.

  The exterior body 11c has a structure that seals the inside by bending the film-like member and connecting the butted edges. And in this exterior body 11c, a part of positive electrode terminal 11a, a part of negative electrode terminal 11b, and electrolyte are enclosed. Further, the end 11d of the exterior body 11c on the side where the positive electrode terminal 11a and the negative electrode terminal 11b extend has a smaller thickness than other portions.

  The film-like member for forming the outer package 11c is a so-called metal laminate film in which resin films are laminated on both surfaces in the thickness direction of the metal film. The metal film is made of, for example, aluminum or an aluminum alloy. The resin film is made of an insulating resin material. Examples of the insulating resin material include polyethylene, polypropylene, polyamide, polyimide, tetrafluoroethylene resin (PTFE), vinylidene fluoride resin (PVDF), modified polypropylene, polyvinyl acetate, polyvinyl acetate, and nylon resin. is there. This resin film functions as an impact absorbing layer that absorbs external impacts, and also functions as an adhesive layer when the film-like member is bent and the butted edges are connected. In addition, about a film-like member, it is preferable that the thickness of a resin film shall be in the range of 10 thru | or 100 micrometers. If the thickness of the resin film is less than 10 μm, the function as the shock absorbing layer may not be ensured. On the other hand, if the thickness of the resin film is greater than 100 μm, the heat dissipation may be reduced.

The positive electrode terminal 11a is made of, for example, aluminum, aluminum alloy, stainless steel, titanium alloy, or the like. In particular, it is preferable to form the positive electrode terminal 11a from aluminum or an aluminum alloy from the viewpoint that electrochemical elution hardly occurs.
The negative electrode terminal 11b is made of, for example, copper, copper alloy, nickel, nickel alloy, stainless steel, aluminum, aluminum alloy, or the like. In particular, it is preferable to form the negative electrode terminal 11b from copper, a copper alloy, nickel, or a nickel alloy from the viewpoint that electrochemical elution is unlikely to occur.

The thickness of the positive electrode terminal 11a and the negative electrode terminal 11b is preferably in the range of 5 to 100 μm.
The electrolyte sealed in the outer package 11c is adjusted by dissolving a lithium salt in a non-aqueous solvent. Examples of the non-aqueous solvent include cyclic carbonates such as ethylene carbonate, propylene carbonate, and butylene carbonate, and linear carbonates such as dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate. Moreover, as a lithium salt, lithium salt with strong electron withdrawing property, for example, LiPF6, LiBF4, LiClO4 etc. can be used.

<1-3> Circuit Board The circuit board 71 includes a circuit breaker (not shown) capable of interrupting the electric circuit leading from the unit cells 11, 21, 31 to the external connector 81, and the operation of the circuit breaker. And an integrated circuit for control (not shown). The control integrated circuit measures the output voltage of each of the unit cells 11, 21, 31. When charging the unit cells 11, 21, 31 and the measured voltage becomes equal to or higher than the first reference voltage, the circuit breaker is closed in order to prevent overcharging of the unit cells 11, 21, 31. On the other hand, when the unit cells 11, 21, 31 are discharged, if the measured voltage is equal to or lower than the second reference voltage, which is lower than the first reference voltage, the circuit is shut off to prevent over discharge of the unit cells 11, 21, 31 Close the vessel. In addition, the voltage across the circuit breaker is also measured, and when the voltage across the circuit breaker is greater than or equal to the third reference voltage, the circuit breaker is prevented from flowing an overcurrent. Close the circuit breaker. The circuit breaker includes a switching element such as an FET, and performs an on / off operation based on a control voltage input from a control integrated circuit to a control terminal of the switching element.

  The circuit board 71 has four conductive lands 72, 73, 74 and 75. The conductive land 72 is connected to the connection piece 17. The conductive lands 73, 74, and 75 are connected to a part of the lead plate laminated structure 101. The conductive lands 73, 74, 75 are longer than the total length L 12 of the unit cells 11, 21, 31 in which the conductive lands 73, 74, 75 are close to the conductive land 72 in the arrangement direction of the unit cells 11, 21, 31. Also concentrated in a short area.

In the arrangement direction of the unit cells 11, 21, 31, the entire length of the conductive land group including the conductive lands 72, 73, 74, 75 is composed of the positive and negative terminals 11 a, 11 b, 21 a, 21 b, 31 a, 31 b. Short compared to the entire length of the terminal group.
One end of the circuit board 71 in the longitudinal direction is provided with a plurality of output terminals (not shown) for outputting a voltage generated between the connection piece 17 of the unit cell 11 and the lead plates 41, 51, 61. . The plurality of output terminals are connected to the external connector 81 via a plurality of lead wires 83. The plurality of output terminals are covered with a covering member 76 made of an insulating resin material. Thereby, electrical insulation between the output terminal and the lead plates 41, 51, 61 and the like can be ensured.

A circuit configuration diagram of the battery pack 1 is shown in FIG.
As shown in FIG. 4, in the battery pack 1, the voltage V <b> 0 generated between the conductive land 72 and the conductive land 75 provided on the circuit board 71, and the voltage V <b> 1 generated between the conductive land 72 and the conductive land 73, A voltage V 2 generated between the conductive land 73 and the conductive land 74 and a voltage V 3 generated between the conductive land 74 and the conductive land 75 are output to the outside via the external connector 81. Here, the voltage V 0 is a driving voltage for an external device connected to the external connector 81. Then, by detecting the voltages V1, V2, and V3, the output voltages of the respective cells 11, 21, and 31 can be individually monitored.

<1-4> Protection Element FIG. 7A shows a side view of the main part in the process of attaching the protection element 13 to the unit cell 11, and FIG. Shown in a).
As shown in FIG. 7A, the protection element 13 includes a rectangular parallelepiped element body 13a and terminal pieces 13b and 13c extending from both ends in the longitudinal direction of the element body 13a. Further, as shown in FIG. 8A, the protection elements 23 and 33 are similarly composed of element bodies 23a and 33a and terminal pieces 23b, 23c, 33b and 33c. In the protection element 13, one terminal piece 13 b is connected to the positive electrode terminal 11 a of the unit cell 11 through the connection piece 15, and the other terminal piece 13 c is connected to the connection piece 17. In the protection element 23, one terminal piece 23 b is connected to the positive electrode terminal 21 a of the unit cell 21 through the connection piece 25, and the other terminal piece 23 c is connected to a part of the lead plate laminated structure 101. In the protection element 33, one terminal piece 33 b is connected to the positive electrode terminal 31 a of the unit cell 31 through the connection piece 35, and the other terminal piece 33 c is connected to a part of the lead plate laminated structure 101. These protection elements 13, 23 and 33 are constituted by thermal fuses. The connection pieces 15 and 17 are made of, for example, aluminum, aluminum alloy, stainless steel, titanium alloy, or the like.

  Here, when heat is conducted from the circuit board 71 to the protection element 13 through the connection piece 17 and the temperature of the protection element 13 is excessively increased, the connection piece connected to the positive electrode terminal 11 a of the unit cell 11 and the circuit board 71. 17 is electrically cut off. Further, when heat is conducted from the circuit board 71 to the protective elements 23 and 33 via the lead plate laminated structure 101 and the temperature of the protective elements 23 and 33 is excessively increased, the positive terminals 21a of the unit cells 21 and 31 are detected. , 31a and the lead plate laminated structure 101 are electrically cut off.

<1-5> Thermistor Element As shown in FIG. 2, the thermistor elements 19 and 29 are attached to the unit cells 11 and 21, respectively. In the unit cell 11, the insulating plate 18 made of a resin material or the like is overlapped with the positive electrode terminal 11 a and a part of the connection pieces 15, 17, a part of the lead plate 41, and the protection element 13 in the thickness direction of the exterior body 11 c. Has been placed. The thermistor element 19 is disposed on one surface of the insulating plate 18 opposite to the protective element 13 side. In the unit cell 21, an insulating plate 28 made of a resin material or the like is disposed so as to overlap with the negative electrode terminal 21 b and part of the lead plates 51 and 61 in the thickness direction of the exterior body 21 c. The thermistor element 29 is disposed on one surface of the insulating plate 28 opposite to the lead plates 51 and 61 side.

  Further, the circuit board 71 is provided with a temperature detection terminal (not shown), and lead wires 19a and 29a led out from the thermistor elements 19 and 29, respectively, are connected to the temperature detection terminal. Each temperature detection terminal is covered with a covering member 78 made of an insulating resin material. Thereby, electrical insulation between the temperature detection terminal and the lead plates 41, 51, 61 and the like can be ensured.

<1-6> External Connector The external connector 81 outputs voltages V0, V1, V2, and V3 generated between the conductive lands 72, 73, 74, and 75 on the circuit board 71 to the outside and a voltage generated at the temperature detection terminal. Is output.
<1-7> Lead Plate Laminate Structure An exploded perspective view of the lead plate laminate structure 101 is shown in FIG. 5A, and a perspective view is shown in FIG.

The lead plate laminated structure 101 includes three lead plates 41, 51, 61, two insulating plates 43, 53, and insulating sheets 45, 55, 65. The lead plate 41, the insulating sheet 45, and the insulating plate 43, the lead plate 51, the insulating plate 53, the exterior label 55, the lead plate 61, and the insulating sheet 65 are laminated in this order.
The lead plate 41 has an elongated, substantially rectangular plate-like main piece portion 41a, and a first extending piece portion 41b extending from one end portion of the main piece portion 41a in one direction along the short direction of the main piece portion 41a. And a second extending piece 41c extending in the one direction from the other end of the main piece 41a, and a direction opposite to the one direction from the position on the one end side with respect to the central part of the main piece 41a. It is comprised from the 3rd extension piece part 41d extended to. Moreover, the front-end | tip part of the 1st extension piece part 41b and the 2nd extension piece part 41c is bent in the direction which goes to the said one end part from the said other end part along the longitudinal direction of the main piece part 41a. The first extension piece 41 b is connected to the negative electrode terminal 11 b of the unit cell 11, and the second extension piece 41 c is connected to the terminal piece 23 c of the protection element 23. The third extending piece 41 d is connected to the conductive land 73 of the circuit board 71. Here, the 1st extension piece part 41b and the 2nd extension piece part 41c are equivalent to the extension piece part for terminal piece connection, and the 3rd extension piece part 41d is equivalent to the extension piece part for land connection.

The lead plate 51 is an elongated, substantially rectangular plate-shaped main piece 51a and in one direction along a short direction (a direction intersecting the extending direction) of the main piece 51a from a substantially central portion of the main piece 51a. a first extending piece portion 51b extending, a second extending piece portion 51c extending in the one direction from one end of the main piece portion 51a, and the one direction from the other end of the main piece portion 51a is The third extending piece portion 51d extends in the opposite direction. Further, the distal end portions of the first extending piece portion 51b and the second extending piece portion 51c are bent in the direction from the one end portion toward the other end portion along the longitudinal direction (extending direction) of the main piece portion 51a. ing. The first extension piece 51 b is connected to the negative electrode terminal 21 b of the unit cell 21, and the second extension piece 51 c is connected to the terminal piece 33 c of the protection element 33. Further, the third extending piece portion 51 d is connected to the conductive land 74 of the circuit board 71. Here, the 1st extension piece part 51b and the 2nd extension piece part 51c are equivalent to the extension piece part for terminal connection , and the 3rd extension piece part 51d is equivalent to the extension piece part for land connection.

  The lead plate 61 includes an elongated substantially rectangular plate-shaped main piece portion 61a and a first extending piece portion 61b extending from one end portion of the main piece portion 61a in one direction along the short direction of the main piece portion 61a. And a second extending piece portion 61c extending from the other end portion of the main piece portion 61a in a direction opposite to the one direction. Moreover, the front-end | tip part of the 1st extension piece part 61b is bent in the direction which goes to the other end part from the said one end part along the longitudinal direction of the main piece part 61a. The first extending piece 61 b is connected to the negative terminal 31 b of the unit cell 31, and the second extending piece 61 c is connected to the conductive land 75 of the circuit board 71. Here, the 1st extension piece part 61b is equivalent to the extension piece part for terminal piece connection, and the 2nd extension piece part 61c is equivalent to the extension piece part for land connection.

  The main pieces 41a, 51a, 61a of the lead plates 41, 51, 61 are connected to the unit cells 11, 21a, 31a and the unit cells 11, 21a, 31a and the negative terminals 11b, 21b, 31b, respectively. It extends along the arrangement direction of 21 and 31. Thereby, in the arrangement direction of the unit cells 11, 21, 31, the positions of the negative terminals 11b, 21b, 31b connected to the second extending piece portions 41c, 51c, 61c and the third extending piece portions 41d, 51d are arranged. , 61d, even if the positions of the conductive lands 73, 74, 75 are displaced, the negative terminals 11b, 21b, 31b and the conductive lands 73, 74, 75 are electrically connected via the lead plates 41, 51, 61. Can be connected.

These lead plates 41, 51, 61 may be, for example, nickel-plated steel plates, tin-plated steel plates, tin-plated copper plates, but plate materials made of other metal materials such as aluminum, aluminum alloy, stainless steel, titanium alloy, etc. Can be used.
The insulating plates 43 and 53 are formed in an elongated rectangular plate shape. The insulating plates 43, 53 and 63 are made of a resin material.

The insulating sheets 45, 55, and 65 are formed in an elongated rectangular shape in plan view. The insulating sheets 45, 55, 65 are formed from a resin material such as polyimide.
FIG. 6A shows a plan view of the lead plate laminated structure 101, and FIG. 6B shows a cross-sectional view taken along the line AA in FIG.
As shown to Fig.6 (a), in the lead board laminated structure 101, the longitudinal direction of the main piece part 41a is rather than the one end part by the side of the insulating sheet 45 continuing to the 1st extension piece part 41b of the main piece part 41a. Is extended by a length L1. Further, the exterior label 55 is extended by a length L2 in the longitudinal direction of the main piece portion 51a from the one end portion of the main piece portion 51a on the third extending piece portion 51d side, and the insulating plate 43 includes the main piece portion. 51a is extended by a length L3 in the longitudinal direction of the main piece portion 51a from one end portion on the first extending piece portion 41b side. The insulating sheet 65 is extended by a length L4 in the longitudinal direction of the main piece portion 61a from one end portion of the main piece portion 61a on the side continuous with the second extending piece portion 61c. The main piece portion 61a is extended by a length L5 in the longitudinal direction of the main piece portion 61a from one end portion of the main piece portion 61a on the second extending piece portion 61c side. In addition, the insulating plate 53 is extended by a length L6 in the longitudinal direction of the main piece 51a from the other end of the main piece 51a on the second extending piece 51c side. Further, the insulating sheet 65 is extended by a length L7 in the longitudinal direction of the main piece portion 61a from the other end portion continuous to the first extending piece portion 61b of the main piece portion 61a. That is, the overlapping portions of the three lead plates 41, 51, 61 are covered with the insulating plates 43, 53, 63 or the insulating sheets 45, 55, 65. As a result, a creeping distance along the surfaces of the insulating sheets 45, 55, 65 or the insulating plates 43, 53 between the lead plates 41, 51, 61 can be secured. The insulation performance between 61 can be improved.

  Further, the lengths of the main piece portions 41a, 51a, 61a in the short direction are longer than the lengths of the insulating plates 43, 53 in the short direction. A gap having a length W1 is formed between both end edges of the insulating plates 43 and 53 in the short direction and the main pieces 51a and 61a. Further, the length of each insulating sheet 45, 55, 65 in the short direction is longer than the length of the insulating plates 43, 53 in the short direction. A gap having a length W2 is formed between both end edges of the insulating sheets 45, 55 and 65 in the short direction and the insulating plates 43 and 53, respectively.

  Here, it is assumed that the length L0 in the longitudinal direction of the main piece portion 61a of the lead plate 61 is set to 65.9 mm. In this case, the lengths L1, L2, L4, and L7 may be set to about 1 mm, for example, and the lengths L3 and L5 may be set to about 2 mm, for example. Further, it is assumed that the length W0 in the short direction of the main piece 61a of the lead plate 61 is set to 3 mm. In this case, the length W1 may be set to 0.75 mm, and the length W2 may be set to 1.0 mm. Further, the thickness T1 (see FIG. 6B) of the lead plate laminated structure 101 may be set to 0.9 mm or less.

  By the way, in the battery pack 1 according to the present embodiment, the conductive lands 73, 74, 75 are in a region shorter than the entire length L12 of the unit cells 11, 21, 31 in the arrangement direction of the unit cells 11, 21, 31. The negative terminals 11b, 21b, and 31b are electrically connected to the conductive lands 73, 74, and 75 by appropriately setting the lengths of the main pieces 41a, 51a, and 61a. Thus, in the arrangement direction of the unit cells 11, 21, 31, the conductive lands 73, 74, 75 are concentrated in a region shorter than the entire length L 12 of the unit cells 11, 21, 31 in the circuit board 71. With the arrangement, the length L11 of the circuit board 71 is shorter than the overall length L12 of the unit cells 11, 21 and 31. Thus, since the size of the circuit board 71 can be reduced, the battery pack 1 can be downsized accordingly.

  Further, the three lead plates 41, 51, 61 are arranged so that a part thereof overlaps when viewed from the thickness direction. The length in the arrangement direction of the unit cells 11, 21, 31 of the lead plate laminated structure 101 is shorter than the sum of the lengths in the arrangement direction of the lead plates 41, 51, 61. Thereby, the occupation area of the lead board laminated structure 101 when it sees from the thickness direction of positive electrode terminal 11a, 21a, 31a and negative electrode terminal 11b, 21b, 31b can be reduced. Therefore, since the space required for housing the lead plate laminated structure 101 in the housing 102 can be reduced, the housing 102 can be reduced in size, and thus the battery pack can be reduced in size. Can do.

<2> Manufacturing Method of Battery Pack Next, a manufacturing method of the battery pack 1 will be described.
FIGS. 7 to 11 are views for explaining a method for manufacturing the battery pack 1.
First, the connection pieces 15 and 17 are connected to the protection element 13. Here, the protection element 13 includes a rectangular parallelepiped element body 13a and terminal pieces 13b and 13c extending to both sides in the longitudinal direction of the element body 13a. The connecting piece 15 is continuous with the main piece 15a, a leg piece 15b extending from one end of the main piece 15a in a direction perpendicular to the longitudinal direction of the main piece 15a, and one tip of the leg piece 15b. It consists of the subpiece 15c. Here, the sub-piece 15c may be superimposed on the tip of the main piece 15a and the two leg pieces 15b when bent in the thickness direction of the leg piece 15b with a portion continuing to the tip of the leg piece 15b as a base point. It is formed in a size that can be done. The connection piece 17 is formed in a substantially rectangular plate shape. Then, the terminal piece 13b of the protective element 13 is overlapped with a part of the main piece portion 15a of the connection piece 15 so that the extending direction of the terminal piece 13b and the extending direction of the main piece portion 15a of the connecting piece 15 are orthogonal to each other. In the combined state, the terminal piece 13b and the connecting piece 15 are connected by spot welding. In addition, the terminal strip 13c and a part of the connection piece 17 of the protection element 13 are overlapped with each other in such a manner that the extending direction of the terminal piece 13c and the extending direction of the connecting piece 17 are orthogonal to each other. The connecting piece 17 is connected by spot welding. Then, the structure which consists of the protection element 13 and the connection pieces 15 and 17 is completed (refer Fig.7 (a)).

  Next, the protection element 13 and the connection pieces 15 and 17 are attached to the unit cell 11. Here, the other leg piece 15b different from the one leg piece 15b continuous with the sub-piece 15c of the connection piece 15 is used as the positive electrode terminal 11a of the unit cell 11 in the structure including the protection element 13 and the connection pieces 15 and 17. Arrange them so that they overlap. At this time, a part of the main piece 15 a of the connection piece 15 and a part of the connection piece 17 come into contact with the end 11 d of the exterior body 11 c of the unit cell 11. Then, by bending the sub-piece 15c in the thickness direction of the leg piece 15b with the portion continuing to the tip of the leg piece 15b as a base point (see the arrow in FIG. 7A), the leg piece 15b and the sub-piece 15c are The positive electrode terminal 11a of the unit cell 11 is sandwiched. At this time, the leg piece 15b and the sub-piece 15c are continuously connected to the leg piece 15b and the sub-piece 15c of the connecting piece 15 with the positive terminal 11a of the unit cell 11 being sandwiched between the connecting piece 15 and the positive terminal 11a. Are connected by spot welding. Then, a structure in which the protection element 13 and the connection pieces 15 and 17 are connected to the unit cell 11 is completed (see FIGS. 7B and 7C).

  Further, as shown in FIGS. 8A to 8C, the protection elements 23 and 33 and the connection pieces 25 and 35 are attached to the unit cells 21 and 31 similarly to the unit cell 11. Here, the connection pieces 25 and 35 are connected only to one of the terminal pieces 23b and 33b extending from the element bodies 23a and 33a of the protection elements 23 and 33, and the other terminal pieces 23c and 33c are opened. This is different from the protection element 13 attached to the unit cell 11. In addition, since the method of connecting the protection elements 23 and 33 and the connection pieces 25 and 35 to the unit cells 21 and 31 is the same as that in the case of the unit cell 11, detailed description is omitted.

  Next, as shown to Fig.9 (a), the end surface from which unit cell 11,21,31 extends in the direction orthogonal to the thickness direction from which positive electrode terminal 11a, 21a, 31a and negative electrode terminal 11b, 21b, 31b extend Are arranged in the same direction. And insulation sheets 27a and 37a are affixed on the other surface side on the opposite side to the one surface side where the protection elements 23 and 33 are arrange | positioned in the edge parts 21d and 31d of the exterior bodies 21c and 31c of the unit cells 21 and 31. Thereafter, the positive terminals 21a and 31a of the unit cells 21 and 31 are bent in the thickness direction so that a part of the connection pieces 25 and 35 is disposed on the insulating sheets 27a and 37a (see arrows in FIG. 9A).

Subsequently, the insulating sheets 27b and 37b are covered so as to cover a part of the connection pieces 25 and 35 disposed on the insulating sheets 27a and 37a (see FIG. 9B).
Next, the lead plate laminated structure 101 is placed on the end portions 11d, 21d, 31d of the exterior bodies 11c, 21c, 31c of the unit cells 11, 21, 31 (see arrows in FIG. 9B). The method for manufacturing the lead plate laminated structure 101 will be described in detail in <4>. At this time, the first extending piece 41 b of the lead plate 41 contacts the negative electrode terminal 11 b of the unit cell 11, and the second extending piece 41 c contacts the terminal piece 23 c of the protection element 23. In addition, the first extending piece 51 b of the lead plate 41 contacts the negative terminal 21 b of the unit cell 21, and the second extending piece 51 c contacts the terminal piece 33 c of the protection element 33. Further, the first extending piece 61 b of the lead plate 61 contacts the negative electrode terminal 31 b of the unit cell 31.

  Then, the lead plate 41, the negative electrode terminal 11b, and the protective element 23 are connected by spot welding of the first extended piece portion 41b, the negative electrode terminal 11b, the second extended piece portion 41c, and the terminal piece 23c of the protective element 23. Terminal piece 23c. Further, the lead plate 51, the negative electrode terminal 21b, and the protective element 33 are connected by spot welding of the first extended piece portion 51b and the negative electrode terminal 21b and the second extended piece portion 51c and the terminal piece 33c of the protective element 33. Terminal piece 33c. Furthermore, the lead plate 61 and the negative electrode terminal 31b are connected by connecting the first extending piece 61b of the lead plate 61 and the negative electrode terminal 31b by spot welding.

Subsequently, the negative terminals 11b, 21b, 31b of the unit cells 11, 21, 31 are bent (see the arrows in FIG. 10A). Then, the extending direction of the connecting piece 17 and the extending directions of the third extending piece portions 41c and 51c of the lead plates 41 and 51 and the second extending piece portion 61c of the lead plate 61 coincide with each other (see FIG. (Refer FIG.10 (b)).
Thereafter, the insulating plates 18 and 28 are disposed on the end portion 11d of the exterior body 11c and the end portion 21d of the exterior body 21c, respectively. Here, a part of the lead plate laminated structure 101 is interposed between the insulating plate 18 and the end portion 11d of the exterior body 11c and between the insulating plate 28 and the end portion 21d of the exterior body 21c. . Subsequently, the thermistor elements 19 and 29 are disposed on the insulating plates 18 and 28, respectively (see FIG. 11A).

  Next, the connection piece 17 and the third extending piece portions 41 c, 51 c, 61 c of the lead plates 41, 51, 61 are respectively joined to the conductive lands 72, 73, 74, 75 of the circuit board 71. The lead wires 19 a and 29 a led out from the thermistor elements 19 and 29 are also connected to the temperature detection terminal of the circuit board 71. Subsequently, the temperature detection terminal is covered with a covering member 78. Thus, the battery core 10 is completed.

Finally, the battery pack 1 is completed by housing the battery core 10 in the housing 102 (see FIG. 1).
<3> Method for Producing Lead Plate Laminate Structure Next, a method for producing the lead plate laminate structure 101 will be described.
FIG. 12 is a diagram for explaining a method of manufacturing the lead plate laminated structure 101. As shown in FIG.

As shown in FIG. 12, lead plate base materials 1041, 1051, and 1061 that are the bases of the lead plates 41, 51, and 61 and insulating plate base materials 1043 and 1053 that are the bases of the insulating plates 43 and 53 are prepared.
Here, the lead plate base material 1041 is a plate material in which a tab 1041b1 in which a through hole 1041a1 is formed and a tab 1041b2 in which a through hole 1041a2 is formed extend from two locations of the lead plate 41. The lead plate base material 1051 is a plate material in which a tab 1051b in which a through hole 1051a is formed extends from one place of the lead plate 51. The lead plate substrate 1061 is a plate material in which a tab 1061b1 in which a through hole 1061a1 is formed and a tab 1061b2 in which a through hole 1061a2 is formed extend from two locations on the lead plate 61.

  The insulating plate base material 1043 is a plate material in which a tab 1043b1 in which a through hole 1043a1 is formed and a tab 1043b2 in which a through hole 1043a2 is formed extend from two places on the insulating plate 43. The insulating plate base material 1053 is a plate material in which a tab 1053b1 in which a through hole 1053a1 is formed and a tab 1053b2 in which a through hole 1053a2 is formed extend from two places on the insulating plate 53.

  Next, the lead plate base materials 1041 and 1051 so that the positions of the through holes 1041a2 and 1043a1 coincide with each other, the positions of the through holes 1043a2, 1053a1 and 1061a1 coincide with each other, and the positions of the through holes 1051a and 1053a2 coincide with each other. 1061 and insulating plate base materials 1043 and 1053 are overlapped. Here, insulating sheets 45 and 55 are interposed between the lead plate substrate 1041 and the insulating plate substrate 1043, respectively. A part of the lead plate base 1061 is covered with an insulating sheet 65.

After that, when heated, the lead plate base materials 1041, 1051, 1061 and the insulating plate base materials 1043, 1053 are bonded to each other by the bonding function of the insulating sheets 45, 55, 65. Here, a structure composed of the lead plate base materials 1041, 1051, 1061 and the insulating plate base materials 1043, 1053 can be formed.
Finally, the tab 1041b1, 1041b2, 1043b1, 1043b2, 1051b, 1053b1, 1053b2, 1061b1, and 1061b2 are cut to generate the lead plate laminated structure 101.

  By the way, in order to ensure the insulation between the lead plates 41, 51, 61, the length L 3 (see FIG. 6A) of the portion of the insulating plate 43 that protrudes from the main piece portion 51 a and the main plate of the insulating plate 53. The length L5 (see FIG. 6A) of the portion protruding from the piece 61a needs to be a predetermined length (for example, 1.5 mm) or more. On the other hand, when the positional accuracy of the lead plates 41, 51, 61 and the insulating plates 43, 53 in the manufacturing process of the lead plate laminated structure 101 is low, the length is required to ensure insulation between the lead plates 41, 51, 61. It is necessary to lengthen L3 and L5 in advance by the positional variation of the lead plates 41, 51, 61 and the insulating plates 43, 53.

  On the other hand, if the manufacturing method of the lead plate laminated structure 101 described above is employed, the positional accuracy of the lead plates 41, 51, 61 and the insulating plates 43, 53 in the lead plate laminated structure 101 can be improved. Therefore, the lengths L3 and L5 can be shortened accordingly. Thereby, the length of the lead plate laminated structure 101 in the longitudinal direction can be reduced. As a result, the battery core 10 and the battery pack 1 can be reduced in size.

Further, since the lead plates 41, 51, 61 and the insulating plates 43, 53 are positioned using the tabs 1041b1, 1041b2, 1043b1, 1043b2, 1051b, 1053b1, 1053b2, 1061b1, 1061b2, the lead plate laminated structure 101 The manufacturing process can be automated.
<4> Summary After all, in the battery pack 1 according to the present embodiment, the length of the entire conductive land group including the conductive lands 72, 73, 74, 75 in the arrangement direction of the unit cells 11, 21, 31 is positive or negative. It is shorter than the overall length of the terminal group consisting of the pole terminals 11a, 11b, 21a, 21b, 31a, 31b. Thereby, in the arrangement direction of the unit cells 11, 21, 31, the conductive lands 72, 73, 74, 75 are concentrated in a region shorter than the entire length of the unit cells 11, 21, 31 in the circuit board 71. With this configuration, the length of the circuit board 71 can be made shorter than the entire length of the unit cells 11, 21, 31, and the size of the circuit board 71 can be reduced. Thus, the size of the circuit board 71 can be reduced, so that the battery pack 1 can be reduced in size.

  The lead plates 41, 51, 61 are formed in an elongated plate shape and extend along the arrangement direction of the unit cells 11, 21, 31 on the positive electrode terminals 11a, 21a, 31a and the negative electrode terminals 11b, 21b, 31b side. It has main pieces 41a, 51a, 61a. Thereby, in the arrangement direction of the unit cells 11, 21, 31, the positions of the negative terminals 11b, 21b, 31b connected to the second extending piece portions 41c, 51c, 61c and the third extending piece portions 41d, 51d are arranged. , 61d, even if the positions of the conductive lands 73, 74, 75 are displaced, the negative terminals 11b, 21b, 31b and the conductive lands 73, 74, 75 are electrically connected via the lead plates 41, 51, 61. Can be connected. That is, even when the conductive lands 73, 74, and 75 are concentrated in a region shorter than the entire length L12 of the unit cells 11, 21, 31, in the arrangement direction of the unit cells 11, 21, 31, the main piece. By appropriately setting the lengths of the portions 41a, 51a, 61a, the negative terminals 11b, 21b, 31b and the conductive lands 73, 74, 75 can be electrically connected.

  Further, the three lead plates 41, 51, 61 are arranged so that a part thereof overlaps when viewed from the thickness direction. The length in the arrangement direction of the unit cells 11, 21, 31 of the lead plate laminated structure 101 is shorter than the sum of the lengths in the arrangement direction of the lead plates 41, 51, 61. Thereby, the occupation area of the lead board laminated structure 101 when it sees from the thickness direction of positive electrode terminal 11a, 21a, 31a and negative electrode terminal 11b, 21b, 31b can be reduced. Therefore, since the space required for housing the lead plate laminated structure 101 in the housing 102 can be reduced, the housing 102 can be reduced in size, and thus the battery pack 1 can be reduced in size. be able to.

  Further, the positive terminal 21 a and the negative terminal 11 b and the conductive land 73 of the circuit board 71 are electrically connected by the lead plate 41. Further, the negative terminal 21 b and the positive terminal 31 a and the conductive land 74 of the circuit board 71 are electrically connected by the lead plate 51. The negative electrode terminal 31 b and the conductive land 75 of the circuit board 71 are electrically connected by the lead plate 61. Thereby, the lead plate 41 and the negative electrode terminal 11b can be connected by resistance welding in a state where the lead plate 41 and the negative electrode terminal 11b are overlapped. Further, the lead plate 51 and the negative electrode terminal 21b, and the lead plate 61 and the negative electrode terminal 31b can be similarly connected by resistance welding. Thereby, the lead wire etc. and the negative electrode terminals 11b, 21b, 31b are connected like the structure formed by connecting the negative electrode terminals 11b, 21b, 31b of the unit cells 11, 21, 31 and the circuit board 71 with the lead wires. A step of connecting by manual work such as soldering can be eliminated.

<Modification>
(1) In the embodiment, the example of the lead plate laminated structure 101 that is laminated in the order of the lead plates 41, 51, and 61 has been described. However, the lamination order of the lead plates 41, 51, and 61 is limited to this. It is not a thing.
FIG. 13A shows an exploded perspective view and FIG. 13B shows a perspective view of the lead plate laminated structure 201 according to this modification.

As shown in FIGS. 13A and 13B, the lead plate laminated structure 201 includes a lead plate 51, an insulating sheet 255, an insulating plate 253, a lead plate 41, an insulating sheet 245, an insulating plate 243, a lead plate 61, The insulating sheets 265 are stacked in this order.
That is, the order of stacking the lead plates 41, 51, 61 may be changed as appropriate as long as electrical insulation can be secured between the lead plates 41, 51, 61 by the insulating member.

(2) The lead plates 41, 51, 61 described in the embodiment are not limited to the shape shown in FIG. 5, and may be appropriately changed according to the specifications of the circuit board.
FIG. 14 shows a perspective view of a main part of a battery core according to this modification, FIG. 15A shows an exploded perspective view of the lead plate laminated structure 201 according to this modification, and FIG. ).
As shown in FIG. 14, the circuit board 371 is smaller than the circuit board 71, and the positions of the conductive lands 373, 374, and 375 in the circuit board 371 are the positions of the conductive lands 73, 74, and 75 in the circuit board 71. Different.

15A and 15B, the positions of the third extending piece portions 341d and 351d on the lead plates 341 and 351 and the second extending piece portion 361c on the lead plate 361 are different.
That is, the shape of the lead plates 341, 351, and 361 may be changed as appropriate according to the shape and position of the circuit board 371 or the positions of the conductive lands 373, 374, and 375 in the circuit board 371.

  (3) In the embodiment, the example in which the first extending pieces 41b and 51b of the lead plates 41 and 51 are connected to the terminal pieces 23c and 33c of the protection elements 23 and 33 has been described, but the present invention is not limited thereto. For example, the first extending piece portions 41 b and 51 b may be directly connected to the positive terminals 21 a and 31 a of the unit cells 21 and 31. Further, the positive electrode terminal 11 a of the unit cell 11 may be directly connected to the conductive land 71 of the circuit board 71.

  According to this configuration, since the process of attaching the protection elements 13, 23, 33 can be omitted, the manufacturing process can be simplified.

  The present invention is widely applicable to all battery packs.

DESCRIPTION OF SYMBOLS 1 Battery pack 3 Case member 5,7 Exterior label 9,27a, 27b, 37a, 37b, 45,55,65,245,255,265 Insulation sheet 10 Battery core 11,21,31 Unit cell 11a, 21a, 31a Positive electrode Terminal 11b, 21b, 31b Negative terminal 11c, 21c Exterior body 11d, 21d End portion 13, 23, 33 Protection element 13a, 23a, 33a Element body 13b, 13c, 23b, 23c, 33b, 33c Terminal piece 15, 17, 25 , 35 Connection piece 15a, 41a, 51a, 61a Main piece 15b Leg piece 15c Subpiece 18, 28, 43, 53, 243, 253 Insulating plate 19, 29 Thermistor element 19a, 29a, 83 Lead wire 41, 51, 61 , 341, 351, 361 Lead plate 41b, 51b, 61b First extension piece (terminal piece connection Extension piece)
41c, 51c, 61c, 361c 2nd extension piece part (extension piece part for terminal piece connection)
41d, 51d, 341d, 351d Third extension piece (land connection extension piece)
71,371 Circuit board 72,73,74,75,373,374,375 Conductive land 76,78 Cover member 81 External connector 101,201 Lead plate laminated structure 102 Case 1041,1051,1061 Lead plate base material 1043,1053 Insulating plate base material 1041b, 1043b, 1051b, 1053b, 1061b Tab 1041a, 1043a, 1051a, 1053a, 1061a Through hole

Claims (3)

A plurality of unit cells each having an exterior body and a plate-like positive electrode terminal projecting in the same direction from the exterior body, and a plate-like negative electrode terminal;
A plurality of conductive lands connected to the plurality of positive terminals and the plurality of negative terminals in the plurality of unit cells are provided, and an end surface of the plurality of unit cells on the side from which the positive terminals and the negative terminals protrude. A circuit board placed close to the
A plurality of lead plates;
The plurality of lead plates are arranged in a state where at least some of them overlap each other when viewed in plan from the thickness direction of the plurality of lead plates, and an insulating plate and a gap between the plurality of lead plates in the overlapping region of the plurality of lead plates An insulating sheet is disposed, and the plurality of lead plates and the insulating plate are bonded to each other by the insulating sheet, and are disposed between the end faces of the plurality of unit cells and the circuit board. A structure,
With
The plurality of unit cells are arranged in a direction intersecting a protruding direction of the positive terminal and the negative terminal,
Wherein said plurality of lead plates in the lead plate laminate structure, a battery pack, wherein the Ru der used to connect the plurality of positive electrode terminal and the plurality of the negative electrode terminal and a plurality of conductive lands respectively electrically . In the arrangement direction of the plurality of unit cells, the length of the conductive land group composed of the plurality of conductive lands on the circuit board is a terminal group composed of the plurality of positive electrode terminals and the plurality of negative electrode terminals in the plurality of unit cells. The battery pack according to claim 1, wherein the battery pack is shorter than the length of the battery pack. At least one lead plate of the plurality of lead plates is:
A main piece portion that is formed in an elongated plate shape and extends along the arrangement direction of the plurality of unit cells on the positive electrode terminal and negative electrode terminal side;
At least one terminal connecting extension piece extending from the main piece portion in one direction intersecting the extending direction of the main piece portion and connected to one of the positive terminal and the negative terminal. When,
From the main piece portion, at least one land connecting extension piece portion extending in a direction opposite to the one direction in which the terminal connection extension piece portion extends and connected to the conductive land. The battery pack according to claim 1 or 2, wherein:

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