JP3893221B2 - Connection lead joining method and battery pack using this joining method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present inventionA joining method for joining positive and negative electrode leads in a battery pack and a connection lead formed of a metal material different from the positive and negative electrodes.Also about this junctionMethodThe present invention relates to a battery pack using.
[0002]
[Prior art]
The proportion of batteries in the volume and weight of portable information devices such as mobile phones and mobile computers is not small, and it is no exaggeration to say that batteries hold the key to reducing the size and weight of portable information devices. For example, the miniaturization of a mobile phone is remarkable, and it has been realized to fit into a pocket. However, it cannot be said that the demand for thinning is satisfied, and it is excellent in portability only when thinning is realized. This thinning also depends on how thin the battery can be made. Conventional lithium-ion secondary batteries are limited in thinning, so a power generation element in which a positive electrode plate and a negative electrode plate are laminated via a polymer electrolyte sheet is housed in an outer case formed of a laminate sheet. Attempts have been made to construct a battery pack for portable information equipment using the lithium polymer secondary battery.
[0003]
[Problems to be solved by the invention]
However, when the power generation element is housed in an outer case formed of a laminate sheet, the positive electrode lead and the negative electrode lead are drawn out between the weld seals of the laminate sheet. Each lead needs to be formed in a very thin metal material. For this reason, positive and negative leads are formed of foil-shaped metal material, and when this is joined to a component such as an external output terminal of a battery pack, joining by spot welding or the like becomes difficult, leading to lead drawing. There was a problem that the joint part peeled off by turning. In particular, since the positive electrode lead is made of aluminum, when joining with phosphor bronze, etc. constituting the external output terminal, aluminum foil has a lower melting temperature and hardness than phosphor bronze, so that an alloy is formed by melting between the joints. Thus, sufficient bonding strength cannot be obtained.
[0004]
  The purpose of the present invention is toIn battery packPulled out of the batteryPositive and negativeLeadConnect the connection lead to connect to the external output terminal.Join with sufficient joint strengthConnectionLeadofJoiningMethodAnd thisJoining methodThe object is to provide a battery pack using.
[0005]
[Means for Solving the Problems]
  To achieve the above objective,Method for joining connection leads of the present inventionIs a foil-like sheet metalsoBeen formedPositive and negativeLeadTo each external output terminalConnectingConnection forLeadPositive and negative electrodesMetal material different from the leadThan the thickness of the positive and negative electrode leadsThickly formedConnection in a battery packLead and saidPositive and negativeLead andJoinJoiningMethodIn the abovePositive and negativeLead and saidConnectionAt the connection position with the leadConnectionBy leadPositive and negativeInsert the lead,Positive and negativeLead andConnectionMelt bonding between leadsAt the same time, melt-bonding between facing connection leadsIt is characterized by that.
[0006]
  thisConnection lead joining methodAccording toPositive and negativeLeadConnectionSince it is sandwiched between leads and melt bonded from both sides,Positive and negativeLead andConnectionEven when the bonding strength between the leads is low, it is compensated by pinching,Positive and negativeLead peel strength is improved.
[0007]
  Furthermore, positive and negative electrodesLead andConnectionWhen melt bonding between leadsBothFace to faceConnectionMelt bonding between leadsRukoAnd byConnectionLeadPositive and negativeThe strength of sandwiching and holding the leads increases, and the bonding strength between them can be improved.
[0008]
  Also,ConnectionLeadPositive and negativeFirst metal material that is the same material as the leadConnectionIt is made of a clad material rolled and joined to a second metal material that is the same material as the lead.ConnectionThe first metal material of the leadPositive and negativeToward the lead sidePositive and negativeInsert the leadMuIn addition to the pinching structurePositive and negativeThe surface in contact with the leadPositive and negativeBy being formed of the same material as the lead, the strength of fusion bonding is improved, and the bonding strength between the two is reliably improved.
[0009]
  Also,Positive and negativeInsert the leadConnectionA protrusion is formed on the inner surface of one side of the lead.And,Positive and negativeWhen the lead is pinched, the protrusionPositive and negativeDouble-sided through leadConnectionLeads contact each other and face each other when melt bonded in this stateConnectionBetween leadsPositive and negativeBecause it is joined with the lead,Positive and negativeBond strength with the lead can be improved.
[0010]
  Also bookInvention battery packIsIn the battery pack in which the connection leads for connecting the positive and negative electrode leads formed of foil-like thin metal plates to the respective external output terminals are formed relatively thick with a metal material different from the positive and negative electrode leads, the positive and negative electrode leads The positive and negative leads are sandwiched by the connection leads at the connection position between the connection lead and the connection lead, and the positive and negative electrode leads and the connection lead are melt-bonded, and the connection leads facing each other are also melt-bonded.It is characterized by that.
In addition, this battery packA secondary battery and a battery protection device including a circuit board on which a protection circuit is formed and a PTC element are accommodated in a pack case, and a positive lead and a negative lead drawn from the secondary battery are accommodated in the pack case.At connection leadConnect to the external output terminal and the battery protection device.RThe secondary batteryIsA power generation element formed by laminating sheet-like positive and negative electrode plates is housed in an outer case that is welded and sealed around the periphery of a pair of laminate sheets, and is formed into a foil with different metal materials from one side of the welded and sealed sides The positive electrode lead and the negative electrode lead pulled outThe abovePositive electrode connected to positive lead and external output terminalConnectionA negative electrode connected between the lead and / or connected to the negative electrode lead and the battery protection deviceConnectionBetween the leadIt is suitably applied to those that have been melt bonded.
[0011]
  According to this configuration,secondaryFoil-like shape drawn from the batteryPositive and negativeLead joins thisConnectionWhen the melting temperature and hardness are lower than the lead, it becomes difficult to join the two.ConnectionBy leadPositive and negativeMelting and bonding with the lead sandwichedByBonding strength is improved and peeling due to lead routing or the like is prevented.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings for understanding of the present invention. The following embodiment is an example embodying the present invention, and does not limit the technical scope of the present invention.
[0013]
In this embodiment, in a battery pack configured as a battery power source of a mobile phone, the lead according to the present invention is used for joining each lead of the positive electrode and the negative electrode drawn out from an internal battery to each component of the battery pack. It shows about the battery pack to which the junction structure is applied.
[0014]
FIG. 1 shows an exploded configuration of a battery pack according to an embodiment. A battery pack 1 is a battery configured as a lithium polymer secondary battery in a pack case 2 including an upper case 2a and a lower case 2b. 3. A battery protection device 8 including a safety unit (hereinafter referred to as SU) 4 that constitutes a protection circuit for protecting the battery 3 and a PTC 5 that is a critical temperature resistance element is housed, and the battery pack 1 is installed in a mobile phone. External output terminals 6a, 6b and 6c for electrical connection are provided.
[0015]
The battery pack 1 is configured to be detachably loaded into a mobile phone, and an upper case 2a constituting the pack case 2 constitutes a part of an outer case of the mobile phone. Therefore, the upper case 2a is formed so as to exhibit strength and aesthetic appearance as a device exterior. The upper case 2a and the lower case 2b are formed by resin molding, accommodate the battery 3 and the battery protection device 8, and the two cases are integrated by ultrasonic bonding.
[0016]
As shown in FIG. 2, the battery 3 has a power generation element 10 formed by laminating a positive electrode plate and a negative electrode plate formed in a sheet shape into a plurality of layers through a separator made of a polymer electrolyte sheet. Is housed in a flexible outer case 11 made of a laminate sheet. This exterior case 11 is formed by folding a laminate sheet cut into strips into two, forming a bag shape by welding and sealing the hatched portions on both sides, and housing the power generation element 10 therein. The positive electrode lead 12 is drawn from the positive electrode plate and the negative electrode lead 13 is drawn from the negative electrode plate, the lead lead side 11b is welded and sealed, and the inside of the outer case 11 is sealed. As shown in FIG. 1, the seal sides 11a on both sides are folded back to the upper surface side to reduce an increase in useless plane space. The battery 3 configured in this way can be configured in a flat plate shape that is thinner than a structure in which the positive and negative electrode plates are wound like a conventional lithium ion secondary battery. Therefore, it can contribute to the thinning of the equipment.
[0017]
  Further, the battery protection device 8 protects the battery 3 from an excessive discharge current due to SU4, short circuit or the like, which is configured on the circuit board 14 to protect the battery 3 from overdischarge or overcharge by controlling charging / discharging. And is supplied in an assembled state as shown in the drawing. As shown in FIG. 3, the battery protection device 8 is attached to a predetermined position of the lower case 2 b with the circuit board 14 and the PTC element 5 in the plate surface direction parallel to the flat plate surface of the battery 3. After the battery protection device 8 is attached to the lower case 2b, the battery 3 is accommodated in the lower case 2b and the positive lead pulled out from the battery 3 as shown in FIG.12And negative electrode lead 13Connect lead 30 and 33Battery protection device 8And external output terminal 6aAfter the connection, the upper case 2a is joined to the lower case 2b to complete the battery pack 1.
[0018]
The procedure of disposing the battery protection device 8, the battery 3, and the external output terminals 6a to 6c in the lower case 2b is performed as described below.
[0019]
As shown in FIG. 1, terminal mounting portions 19a, 19b, and 19c are formed as recesses in the 90-degree direction from the side surface of the lower case 2b to the back surface side, and the bottom surface of this recess is shown in FIG. As described above, slit-like terminal insertion holes 22 are formed at two locations on the upper and lower sides. As shown in FIG. 1, the external output terminals 6a, 6b, 6c formed in a U-shape are press-fitted into the terminal insertion holes 22 from both ends. Since one end of the external output terminal 6a serving as the positive electrode terminal is formed long, the insertion tip is positioned above the joint hole 23 formed in the lower case 2b when mounted on the lower case 2b. The insertion tip comes into view from the joint hole 23. The end of the positive electrode connection lead 30 shown in FIG. 1 is superimposed on the insertion tip on the joint hole 23, and both are joined by spot welding. FIG. 6 is a cross-sectional view showing the mounting state of the external output terminal 6a. The end of the positive electrode connection lead 30 is placed on the insertion tip of the external output terminal 6a, and one of the welding electrodes is connected as indicated by the up and down arrows. It is inserted from the joint hole 23 and applied to the insertion tip of the external output terminal 6a, the other is applied to the positive electrode connection lead 30, and spot welding is performed, and both are joined.
[0020]
In addition, the external output terminals 6a to 6c are press-fitted from the upper and lower terminal insertion holes 22 and 22 to be fitted into the lower case 2b, and are joined to the respective components disposed in the lower case 2b. It becomes a mounting structure. Further, as shown in FIG. 6, since it is mounted in close contact with the bottom surfaces of the terminal mounting portions 19 a to 19 c, the connection probe 44 that is in pressure contact for electrical connection when the battery pack 1 is mounted on a mobile phone. A reliable connection state can be obtained even when pressure is applied, and an electrical connection with low contact resistance is achieved.
[0021]
Next, as shown in FIG. 3, the test terminals 24a and 24b provided in the battery protection device 8 are positioned by being fitted into the test terminal windows 29a and 29b formed in the lower case 2b, so that the battery protection device 8 is positioned. Is disposed at the end of the lower case 2b. FIG. 7 is a cross-sectional view showing a state in which the test terminal 24b is disposed. The test terminal 24b is bent into a U-shaped portion at the tip of the test terminal 24b. It is fixed to 2b. Since the tips of the test terminals 24a and 24b are in a position to be seen from the outside through the test terminal windows 29a and 29b, the test probe 43 is brought into contact with the test probe 43 at the time of manufacturing inspection after completion of the battery pack 1 and used for electrical inspection. Is done.
[0022]
When the battery protection device 8 is positioned on the lower case 2b, as shown in FIG. 8, the circuit board 14 constituting the SU 4 is disposed under the external output terminals 6a, 6b, 6c attached to the lower case 2b. Then, the external output terminals 6a, 6b, and 6c are in contact with the soldered lands 31a, 31b, and 31c formed on the circuit board 14, respectively. By connecting the external output terminals 6a, 6b, 6c to the solder lands 31a, 31b, 31c, respectively, terminal connection is made, and at the same time, the external output terminals 6a-6c and the battery protection device 8 are mounted on the lower case 2b. The position is fixed to the position.
[0023]
As shown in FIG. 8 (b), the circuit board 14 and the plate surface of the PTC element 5 are arranged in parallel with the bottom surface of the lower case 2b. Space can be reduced. Furthermore, as shown in FIG. 4, a space in the thickness direction for accommodating the lead lead-out side 11b of the battery 3 on the battery protection device 8 can be created, and the battery pack can be formed without creating a useless space in the pack case 2. The size reduction of 1 is improved. Further, the lead lead-out side 11 b covers the upper surface of the battery protection device 8, thereby preventing the positive electrode lead 12 and the negative electrode lead 13 drawn out from the battery 3 from contacting the battery protection device 8. In the state in which the battery protection device 8 is disposed, the negative electrode connection lead 33 and the positive electrode connection lead 30 provided in the battery protection device 8 are arranged in an upright state at the end of the lower case 2b.
[0024]
Next, as shown in FIG. 4, the battery 3 is accommodated in the lower case 2 b with the lead lead-out side 11 b facing the battery protection device 8. The battery 3 is disposed so that the lead lead-out side 11b covers the battery protection device 8, and the accommodation position is positioned between the concave portion 32 and the positioning convex portion 34 formed in the lower case 2b. The positive electrode lead (foil-shaped lead) 12 drawn out from the lead lead-out side 11b of the battery 3 is a positive electrode connection lead (mating lead) 30, and the negative electrode lead (foil-shaped lead) 13 is a negative electrode connecting lead (mating lead) 33. Face each other. The positive electrode lead 12 and the positive electrode connection lead 30 and the negative electrode lead 13 and the negative electrode connection lead 33 are joined by spot welding.
[0025]
FIG. 9 shows the bonding between the positive electrode lead 12 and the positive electrode connection lead 30, and the positive electrode lead 12 is formed in a foil shape with aluminum having a thickness of 80 μm and is in a state of extremely low strength from its hardness, In order to ensure the joining by spot welding, spot welding is performed with the positive electrode lead 12 sandwiched between the positive electrode connection lead 30 and the bonding side 30a. The joint side 30a can be formed of a separate member, but here, as shown in FIG. 10, an extended side is formed at the tip of the positive electrode connection lead 30, and this is used as the joint side 30a. As shown in b), the positive electrode lead 12 is sandwiched by being bent when the positive electrode lead 12 is joined. As described above, the positive electrode lead 12 is sandwiched between the positive electrode connection lead 30 and the joint side 30a and spot-welded, so that the positive electrode lead 12 is pinched by the positive electrode connection lead 30 not only at the welding point but also in a wide area where the joint side 30a overlaps. Therefore, the bonding strength is significantly improved.
[0026]
The joining structure that sandwiches and joins the positive electrode lead 12 can also be configured as shown in FIGS. 11 (a), 11 (b), and 11 (c). In the configuration shown in FIG. 11A, the positive electrode lead 12 is sandwiched, and at the same time, a surface where the positive electrode connection lead 30 and the joint side 30a directly contact each other is provided, and the position where the positive electrode lead 12 is sandwiched and the position where the positive electrode lead 12 is directly contacted are provided. Spot weld. In this configuration, since the positive electrode connection lead 30 and the bonding side 30a are directly bonded, it is possible to supplement the bonding strength at the sandwiched position of the positive electrode lead 12 where an alloy due to melting is less likely to occur. Further, as shown in FIG. 11B, when a protrusion is formed on the joint side 30a and spot welding is performed with the protrusion penetrating through the positive electrode lead 12 and contacting the positive electrode connection lead 30 during superposition, the protrusion Since the positive electrode lead 12, the positive electrode connection lead 30, and the bonding side 30a are fused at the formation site, bonding with higher bonding strength can be performed. Further, as shown in FIG. 11C, when the positive electrode connection lead 30 is formed of a clad plate in which aluminum and phosphor bronze are rolled and joined, and the positive electrode lead 12 is sandwiched between the aluminum surfaces and spot welding is performed, the positive electrode lead 12 Since it is welded between the same kind of aluminum and the aluminum surface of a clad board, joining is made more reliably.
[0027]
Next, as shown in FIG. 9A, after the positive electrode lead 12 and the positive electrode connection lead 30 are joined, as shown in FIG. 9B, it is bent onto the lead lead-out side 11b of the battery 3. The joint portion between the negative electrode lead 13 and the negative electrode connection lead 33 is also bent in the same manner. Since there is a lead lead-out side 11b between the bent portion and the battery protection device 8, the positive electrode lead 12 and the negative electrode lead 13 do not contact the battery protection device 8 and cause an abnormality. Further, the insulating property is more reliably ensured by applying an insulating coating to the soldering surface of the circuit board 14 after the external output terminals 6a to 6c are soldered.
[0028]
Thus, since the positive electrode lead 12 and the negative electrode lead 13 are drawn out from the same one side of the battery 3 and the battery protection device 8 is disposed on the lead drawing side, the battery 3 and the battery protection device 8 are connected. Since there is no lead routing as in the conventional configuration for connection between the external output terminals 6a to 6c and the battery protection device 8 are fixed at predetermined positions of the lower case 2b, they are accommodated in the pack case 2. Connection between each component is made robust and reliable, and the battery pack 1 has robustness in addition to thinning for use in a portable device.
[0029]
After each component is accommodated in the lower case 2b by the process described above, the upper case 2a is joined to the lower case 2b by ultrasonic welding, and as shown in FIG. 12, the thin battery pack 1 is assembled. . After this assembly, an inspection probe is inserted into the test terminal windows 29a and 29b to contact the test terminals 24a and 24b, and an inspection is performed as to whether or not the battery pack 1 operates normally. A blindfold sheet is attached to the recess 35 provided with the test terminal windows 29a and 29b, the bonding window 23, and the like of the battery pack 1 that has passed the inspection, and each opening is closed.
[0030]
FIG. 12A is a plan view of the battery pack 1 viewed from the lower case 2b side. The surface facing the flat surface of the battery 3 is formed thin, and the battery 3 is elastic when its thickness changes due to expansion. An elastically deformable surface 15 that is deformed automatically is formed. An outer peripheral portion 16 is formed so as to protrude so as to surround the elastic deformation surface 15. Further, since the elastic deformation surface 15 is formed thin, the stainless thin plate (metal thin plate) 7 is not formed on the portion excluding the peripheral portion of the elastic deformation surface 15 in order to prevent the battery 3 from being damaged by the piercing with the blade or the like. Is attached. Projections 7 a that abut on the outer peripheral portion 16 are formed at the corners of the stainless steel thin plate 7 so that the stainless steel thin plate 7 can be positioned when the stainless steel thin plate 7 is adhered to the elastic deformation surface 15.
[0031]
The stainless steel thin plate 7 may be attached to the entire surface of the elastic deformation surface 15. If the thickness of the stainless steel thin plate 7 is set to a minimum thickness that can provide strength against piercing, the amount of deformation of the elastic deformation surface 15 increases. Since the peripheral portion is also deformed following the deformation of the elastic deformation surface 15, the elastic deformation of the elastic deformation surface 15 is not hindered.
[0032]
FIG. 13 is a cross-sectional view taken along the line AA in FIG. 12A, and the elastic deformation surface 15 is formed to have a thickness of 0.22 mm in this configuration, and around the elastic deformation surface 15, An outer peripheral portion 16 is formed at a predetermined height. A protruding height of the outer peripheral portion 16 is formed so that a step H is formed between the top portion of the outer peripheral portion 16 and the surface of the stainless steel thin plate 7 attached to the elastic deformation surface 15. Note that the step H in this configuration is set to 0.4 mm.
[0033]
In the battery 3, the electrode plate expands due to repeated charge / discharge and aging, and the thickness of the battery 3 increases. When the thickness of the battery 3 increases due to the expansion of the battery 3 and exceeds the height of the battery housing space between the upper case 2a and the lower case 2b, the pressure due to the expansion of the battery 3 is formed thin and easily deforms. The elastic deformation surface 15 is pushed out and elastically deformed.
[0034]
Since the expansion of the electrode plate of the battery 3 having the electrode plate laminated structure occurs as a change in the thickness of the entire battery 3, the elastic deformation surface 15 is pushed up on the average in contact with the battery 3, and the deformation is shown in FIG. As shown in FIG. 4, the elastic deformation occurs at the peripheral portion in contact with the outer peripheral portion 16. The thickness of the lithium polymer secondary battery in this configuration is 3.91 mm, and the thickness due to expansion over the entire life after repeated charge and discharge is 4.31 mm, and data that causes expansion of 0.4 mm has been acquired. . As described above, since the space by the step H having a height of 0.4 mm surrounded by the outer peripheral portion 16 is formed on the elastic deformation surface 15, the battery pack 1 can be used even when the entire life of the battery pack 1 has passed. There is no change in the maximum thickness. Further, since the stainless thin plate 7 is stuck on the surface of the elastically deformable surface 15 so as to leave the periphery of the elastically deformable surface 15, the flat state is maintained by the elastic deformation of the surroundings in combination with the average thickness change of the battery 3. Bulges into the outer periphery 16. Therefore, the expansion of the battery according to the conventional configuration does not cause an arc-shaped bulge to give an uncomfortable feeling to the shape of the battery pack, and the arc-shaped bulge does not adversely affect the device.
[0035]
The battery pack 1 having the above-described configuration is loaded into a mobile phone 9 as shown in a sectional view in FIG. Since the battery pack 1 is thinned, the mobile phone 9 itself is also thinned, and a mobile phone 9 having a slim configuration that can be inserted into a pocket is realized. On the opposite surface (front side) of the cellular phone 9 on which the battery pack 1 is loaded, a push key 17, a multilayer circuit board 18 on which a contact circuit is formed by the push key 17, and a support for supporting the multilayer circuit board 18 are provided. A plate 19 is disposed, and the space between the support plate 19 and the battery pack 1 is about 0.05 mm between the outer peripheral portion 16 and the stainless thin plate 7 adhered on the elastic deformation surface 15. Is provided with a gap of about 0.45 mm.
[0036]
With this configuration, the outer peripheral portion 16 serves to support the deformation of the support plate 19 when a strong pressure is applied from the surface side of the mobile phone 9. Further, in the battery 3, expansion of the electrode plate occurs due to charging / discharging or aging, and the thickness of the battery increases. However, the elastic deformation surface 15 is elastically deformed corresponding to the expansion of the battery 3, and the outer peripheral portion as described above. The thickness change due to the expansion is settled in the space formed in the space surrounded by 16, and the influence of the expansion is not exerted on the device side.
[0037]
In the above configuration, the basic configuration is that the dimension in the thickness direction of the storage space of the battery 3 in the pack case 2 is slightly larger than the thickness of the battery 3 in consideration of the thickness dimension error of the battery 3. Since the elastic deformation surface 15 is configured to be elastically deformed, the dimension in the thickness direction of the accommodation space of the battery 3 in the pack case 2 can be formed smaller than the thickness dimension of the battery 3. By accommodating the battery 3 in the pack case 2 formed in this way, the battery 3 is constantly pressurized in the compressing direction from both sides by the elastic deformation surface 15, and the expansion of the electrode plate is suppressed. Effects can be obtained.
[0038]
When the battery 3 is not expanded, the elastic deformation surfaces 15 and 25 are formed to have a thickness that is not pressurized in the compression direction from the elastic deformation surfaces 15 and 25. When the battery 3 expands, the elastic deformation surfaces 15 and 25 are formed. The effect of suppressing the expansion of the electrode plate can be obtained even when the pressure in the compression direction is applied by the force to be pushed out.
[0039]
Further, when the elastic deformation surfaces 15, 25 a, 25 b are elastically deformed due to the expansion of the battery 3, if the thickness of the peripheral portion where the amount of deformation is the largest is formed thinner than the thickness of other portions, the elastic deformation of the peripheral portion is facilitated. Further, the followability to the expansion of the battery 3 can be improved. Conversely, if the thickness of the peripheral part is made thicker than the thickness of the other part, it becomes difficult to deform, so that a compressive force is applied to the battery 3 against the expansion of the battery 3 and the electrode plate of the battery 3 is expanded. Therefore, the expansion of the battery 3 can be suppressed.
[0040]
Although the configuration of the battery pack 1 described above has been described with respect to an example applied as a battery power source of a mobile phone, the same configuration can be applied to a mobile computer, an electronic notebook, a transceiver, and the like.
[0041]
【The invention's effect】
  As described above, according to the present invention,In the battery pack, the positive and negative electrode leads drawn from the secondary battery are connected to the connection leads having different melting temperatures and hardnesses. The positive and negative electrode leads are sandwiched between the connection leads and melt-bonded from both sides. Even when the bonding strength between the leads is low, the peel strength of the positive and negative leads is improved, and the positive and negative leads and the connecting leads are melt bonded together, and the connecting leads facing each other are also melt bonded. The strength of the lead sandwiching the positive and negative leads increases, and the bonding strength between them can be improved.Stable joining is possibleTrustA highly reliable battery pack can be configured.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view showing a configuration of a battery pack according to an embodiment.
FIG. 2 is a plan view showing a schematic configuration of a battery.
FIG. 3 is a perspective view showing a state in which a battery protection device is disposed in a lower case.
FIG. 4 is a perspective view showing a state where a battery protection device and a battery are arranged in a lower case.
FIG. 5 is a side view of a lower case showing a configuration of a terminal mounting portion.
FIG. 6 is a cross-sectional view illustrating mounting of an external output terminal and bonding with a positive electrode connection lead.
FIG. 7 is a cross-sectional view illustrating a test terminal mounting structure.
8A is a plan view and FIG. 8B is a side view showing an arrangement state of the battery protection device.
FIG. 9 is a cross-sectional view showing bonding (a) between a positive electrode lead and a positive electrode connection lead and a storage state (b) of the lead.
10A is a perspective view showing a configuration in which a joining plate is provided on a positive electrode connection lead, and FIG. 10B is a perspective view showing a form at the time of joining.
FIG. 11 is a cross-sectional view showing a modified example of the joint structure between the positive electrode connection lead and the positive electrode lead.
FIG. 12A is a plan view showing a completed state of the battery pack, and FIG.
FIGS. 13A and 13B are cross-sectional views taken along line AA when the battery is expanded, in which FIG.
FIG. 14 is a cross-sectional view showing a state in which a battery pack is loaded in a mobile phone.
[Explanation of symbols]
1 Battery pack
2 Pack cases
2a Upper case
2b Lower case
3 batteries
4 Protection circuit (SU)
5 PTC element
6a, 6b, 6c External output terminal
10 Power generation elements
11 Exterior case
12 Positive electrode lead (foil-shaped lead)
13 Negative electrode lead (foil-shaped lead)
30 Positive connection lead (mating lead)
33 Negative connection lead (mating lead)

Claims (5)

Battery pack connection leads for connection formed by a foil-like thin metal plate were positive and negative electrode lead to respective external output terminals, are formed larger than the thickness of the positive and negative electrode lead and the metal material different positive and negative electrode lead In the joining method of joining the connection lead and the positive and negative electrode leads,
Sandwiching positive and negative electrode lead by connection leads at the connection position between the positive and negative electrode lead and the connecting leads, as well as melt bonding between the positive and negative electrode leads and the connecting leads, also between the facing connection leads and characterized by melt bonding bonding method of connection leads. Connection leads, it is formed by the first clad material rolled bonded to the second metal material to a metal material which is a connection lead of the same material of the same material as the positive and negative electrode lead, the connection leads of the first joining method of claim 1, wherein the connection leads, characterized in that sandwich the positive and negative electrode leads toward the metallic material to the positive and negative electrode lead side. Connection lead bonding method according to claim 1 or 2, characterized in that projections on one side of the inner surface of the connection leads sandwiching the positive and negative electrode leads are formed. In the battery pack in which the connection leads for connecting the positive and negative electrode leads formed of foil-like thin metal plates to the respective external output terminals are formed relatively thick with a metal material different from the positive and negative electrode leads,
A positive and negative electrode lead is sandwiched between connecting positive and negative electrode leads and the connecting lead, and the positive and negative electrode leads and the connecting lead are melt-bonded and the connecting leads facing each other are also melt-bonded. Battery pack . The battery pack accommodates a secondary battery, a battery protection device configured to include a circuit board on which a protection circuit is formed, and a PTC element in a pack case, and a positive electrode lead and a negative electrode lead drawn from the secondary battery. Ri Na connected to an external output terminal and the battery protection device in connection leads,
The secondary battery houses a power generating element formed by stacking a sheet-shaped positive and negative electrode plates in the outer casing welded sealed peripheral portions of the pair of laminated sheets, different metal material from each welded sealed one side The positive electrode lead and the negative electrode lead formed in foil shape are drawn out ,
Claims, characterized in that the melted bonding between the positive electrode lead and the external output between the connected positive connector leads to the terminals and / or the negative electrode lead and the negative electrode connection lead connected to the battery protection device 4. The battery pack according to 4 .

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