CN217588959U

CN217588959U - Online film inserting equipment and series welding film inserting equipment

Info

Publication number: CN217588959U
Application number: CN202220454940.8U
Authority: CN
Inventors: 姜毅
Original assignee: Wuxi Autowell Technology Co Ltd
Current assignee: Wuxi Autowell Technology Co Ltd
Priority date: 2022-03-02
Filing date: 2022-03-02
Publication date: 2022-10-14
Anticipated expiration: 2032-03-02

Abstract

The application discloses insert membrane equipment and stringer and insert membrane equipment on line, should insert membrane equipment on line include that membrane tape material is rolled up, is cut membrane device and membrane strip handling device, wherein: the film tape roll is used for carrying a film tape roll; the film cutting device cuts the film tape drawn from the film tape material roll to obtain n film strips; the film strip carrying device clamps the n film strips from the film cutting device, separates the n film strips at preset intervals and synchronously moves the n film strips to the corresponding film inserting stations in the battery string to insert films, and the preset intervals are the intervals between two adjacent film inserting stations in the battery string. This application is through setting up the cutting that the membrane device realized the membrane area, through setting up membrane strip handling device, realizes picking up and the transport of the membrane strip that obtains after cutting, and the subsequent membrane operation of inserting of being convenient for has reduced artifical the participation, has improved the membrane strip and has generated and the efficiency that targets in place.

Description

Online film inserting equipment and series welding film inserting equipment

Technical Field

The utility model belongs to the technical field of photovoltaic module production, a insert membrane equipment and stringer and insert membrane equipment on line is related to.

Background

As the thickness of the battery piece becomes thinner and thinner, when the adjacent battery pieces are interconnected by using the solder strip, the adjacent edges of the battery pieces are easy to be cracked, and in order to solve the problem, the current assembly factory provides a requirement for inserting a film strip between the adjacent battery pieces.

In original production mode, at first utilize the stringer to accomplish the stringer between the battery piece, then insert the membrane strip to between the adjacent battery piece through the manual work, this kind of mode is inefficient, and need form the difference in height between the adjacent battery piece because of the inserting of membrane strip, and the battery piece is cracked because of manual operation causes easily, consequently needs a solution that can insert the membrane strip automatically urgently.

SUMMERY OF THE UTILITY MODEL

In order to solve the problems in the related art, the application provides an online film inserting device and a series welding film inserting device, and the technical scheme is as follows:

in a first aspect, the present application provides an online film inserting apparatus, which includes a film tape roll, a film cutting device, and a film strip conveying device, wherein:

the film tape roll is used for carrying a film tape roll;

the film cutting device cuts the film tape drawn from the film tape roll to obtain n film strips;

and the film strip carrying device clamps the n film strips from the film cutting device, separates the n film strips at a preset interval and synchronously moves the n film strips to the corresponding film inserting stations in the battery string to insert films, wherein the preset interval is the distance between two adjacent film inserting stations in the battery string.

Optionally, the film cutting device is further configured to stretch the n cut film strips, and the film strip handling device clamps the n stretched film strips from the film cutting device;

or,

and the film strip conveying device clamps the n film strips from the film cutting device and stretches the n film strips before film insertion.

Optionally, the film cutting device draws a film belt from the film belt material roll and cuts the drawn film belt;

or,

the film strip carrying device pulls out a film strip from the film strip material roll and passes through the film cutting device, and the film cutting device cuts the film strip passing through the film cutting device.

Optionally, the film cutting device includes a film supply device and a film cutting assembly, the film cutting assembly includes a first film strip clamping part, a second film strip clamping part and a cutting part, wherein:

the film belt is drawn out from the film supply device and then passes through the clamping film cutting channel of the film cutting assembly;

the first film strip clamping part and the second film strip clamping part respectively clamp two side edges of the film strip passing through the clamping and film cutting channel, and the cutting part is used for cutting the clamped film strip to obtain a film strip.

Optionally, the film cutting device further comprises a film belt traction device, and the film belt traction device is used for drawing a film belt out of the film supply device and passing through a clamping film cutting channel of the film cutting device.

Optionally, the first and second film strip holding portions are further configured to be horizontally distanced from each other to achieve stretching of the clamped film strip section.

Optionally, first membrane area clamping part with second membrane area clamping part structure is the same, first membrane area clamping part includes the mounting panel and installs film cutting chuck, chuck elevating system, tensile actuating mechanism on the mounting panel, wherein:

the film cutting chuck is in transmission connection with the chuck lifting mechanism and the stretching driving mechanism respectively, the chuck lifting mechanism drives the film cutting chuck to descend so as to press the film belt passing through the clamping and film cutting channel, and the stretching driving mechanism drives the film cutting chuck to move towards the direction which is far away from the central line of the clamping and film cutting channel and is horizontally, vertically and outwards so as to stretch the clamped film belt;

the mounting plate is located the outside of surely membrane chuck, and for the rigidity of centre gripping surely membrane passageway.

Optionally, first membrane area clamping part still includes mounting panel, lift post under the membrane cutting chuck on the membrane cutting chuck, wherein:

the upper mounting plate of the film cutting chuck is mounted on the lower mounting plate of the film cutting chuck through the lifting column;

the upper end of the film cutting chuck is fixed on the upper mounting plate of the film cutting chuck, and the lower pressing surface of the film cutting chuck penetrates through the lower mounting plate of the film cutting chuck;

the driving end of the chuck lifting mechanism is fixedly connected with the upper film cutting chuck mounting plate so as to drive the upper film cutting chuck mounting plate to lift relative to the lower film cutting chuck mounting plate;

the driving end of the stretching driving mechanism is fixedly connected with the lower film cutting chuck mounting plate so as to drive the film cutting chuck to move towards the direction which is far away from the central line of the clamping film cutting channel and is horizontally, vertically and outwards through the lower film cutting chuck mounting plate.

Optionally, the cutting part comprises at least one hot filament cutter, a first connecting plate, a second connecting plate, a first lifting driving part and a second lifting driving part, wherein:

two ends of the hot filament are respectively arranged on the first connecting plate and the second connecting plate;

the driving end of the first lifting driving part is connected with the first connecting plate, the driving end of the second lifting driving part is connected with the second connecting plate, and the first lifting driving part and the second lifting driving part are matched to drive the first connecting plate and the second connecting plate to lift so as to drive the hot cutting wire to lift;

wherein the extending direction of the hot filament is vertical to the drawing direction of the film belt.

Optionally, the film supply device includes a film belt passing support, a first film belt bearing plate, a second film belt bearing plate, a first bearing plate driving mechanism, and a second bearing plate driving mechanism, wherein:

the discharge hole of the membrane band passing support is positioned at the feed inlet of the clamping and membrane cutting channel, and the pulled membrane band enters the clamping and membrane cutting channel from the membrane band passing support;

the first film belt supporting plate and the second film belt supporting plate are respectively positioned at two sides of the clamping and film cutting channel and are respectively matched with the first film belt clamping part and the second film belt clamping part up and down to clamp the film belts;

the first supporting plate driving mechanism and the second supporting plate driving mechanism respectively drive the first film belt supporting plate and the second film belt supporting plate to be away from each other so as to stretch the clamped film strips.

Optionally, the film supply device further comprises a film belt bearing plate, a pressing plate and a pressing cylinder, wherein:

the film belt bearing plate is positioned between the discharge hole of the film belt passing support and the feed inlet of the clamping film cutting channel so as to bear a film belt pulled out from the film belt passing support;

the pressing plate is located above the film strip bearing plate, the driving end of the pressing cylinder is fixedly connected with the pressing plate, and the pressing cylinder drives the pressing plate to move towards the film strip bearing plate so as to press the film strip at the film strip bearing plate.

Optionally, the first film belt supporting plate and the second film belt supporting plate are provided with an avoiding groove opposite to the cutting wire on the upper end face for supporting the film belt.

Optionally, the film tape traction device includes a film tape traction chuck, a chuck driving mechanism and a traction moving mechanism, wherein:

the traction moving mechanism is in transmission connection with the traction chuck, and a driving end of the chuck driving mechanism is connected with the traction chuck;

the traction moving mechanism at least drives the traction chuck to the film supply device, and the chuck driving mechanism drives the traction chuck to clamp the film belt at the film supply device.

Optionally, membrane strip handling device is including two sets of membrane strip transport portions that set up relatively, and two sets of membrane strip transport portions are the both ends of n membrane strips of centre gripping respectively, and to every membrane strip transport portion of group, membrane strip transport portion includes n group's chucks, lower chuck mounting rail and actuating mechanism, wherein:

each group of chucks comprises an upper chuck and a lower chuck which are opposite up and down and used for clamping the membrane strip, the lower chuck of each group of chucks is arranged on the lower chuck mounting rail, the driving mechanism is in transmission connection with the n chucks, and the driving mechanism drives the n groups of chucks to move along the lower chuck mounting rail.

Optionally, the 2 nd to nth lower chucks are movably mounted on the lower chuck mounting rail, and the chucks of each group are connected with each other through a flexible member;

the 1 st group of chucks are fixedly installed, the nth group of chucks are in transmission connection with the driving mechanism through a connecting piece, the driving mechanism drives the nth group of chucks to move along the lower chuck installation track, and the flexible piece drives the chucks to mutually approach and mutually separate so as to adjust the distance between n clamped film strips.

Optionally, the film strip conveying portion further comprises an upper chuck mounting rail, each upper chuck is mounted on the upper chuck mounting rail, the middle portion of each upper chuck and the middle portion of each lower chuck are connected through a pin shaft, the film strip conveying portion further comprises first clamping action portions mounted at two ends of the upper chuck mounting rail, the two first clamping action portions synchronously act to jointly drive the upper chuck mounting rail to ascend or descend, when the upper chuck mounting rail ascends, the tail end of each upper chuck is driven to ascend, and the clamping portions of each upper chuck rotate around the corresponding rotating shaft to press against the clamping portions of the corresponding lower chuck.

Optionally, the first clamping action part comprises a connecting plate, a sliding device and a lifting cylinder, wherein:

the connecting plate is arranged on the sliding device;

the end part of the upper chuck mounting rail penetrates through the connecting plate to be connected with the driving end of the lifting cylinder;

the lifting cylinder drives the upper chuck mounting rail to ascend along the sliding device so as to drive the mounting parts of the upper chucks on the upper chuck mounting rail to ascend, and further drives the clamping parts of the upper chucks to move around the rotating shaft towards the clamping parts of the corresponding lower chucks, so that the chucks are clamped;

the lifting cylinder drives the upper chuck mounting rail to descend along the sliding device so as to drive the mounting parts of the upper chucks on the upper chuck mounting rail to descend, and further drive the clamping parts of the upper chucks to move around the rotating shaft away from the clamping parts of the corresponding lower chucks, so that the opening of the chucks is realized.

Optionally, the last chuck of each group chuck and the tail end of lower chuck pass through spring coupling, and the last chuck of each group chuck and the intermediate part of lower chuck are installed in the pivot, membrane strip transport portion still includes second clamping action portion, second clamping action portion includes depression bar and depression bar actuating mechanism, wherein:

the driving end of the pressure lever driving mechanism is connected with the pressure lever, and the pressure lever is arranged above the clamping part of each upper chuck;

the pressing rod driving mechanism drives the pressing rods downwards, and the pressing rods press the clamping parts of the upper clamping heads to the corresponding clamping parts of the lower clamping heads to open the clamping heads;

the pressing rod driving mechanism drives the pressing rod upwards, the pressing rod is far away from the clamping parts of the upper clamping heads, and the clamping parts of the upper clamping heads are separated from the clamping parts of the lower clamping heads under the action of the corresponding springs, so that the clamping of the clamping heads is realized.

Optionally, the driving mechanism includes a driving motor, a driving wheel, a driven wheel and a conveying belt, wherein:

the driving wheel and the driven wheel are respectively arranged at two ends of the mounting clamp where the lower chuck mounting rail is arranged;

the transmission belt is sleeved on the driving wheel and the driven wheel;

the nth group of chucks are fixed on the conveying belt through the connecting piece, and the driving end of the driving motor is in transmission connection with the driving wheel;

the driving motor rotates in the positive direction, and the nth group of chucks are driven to move towards the direction close to the 1 st group of chucks along the lower chuck mounting track through the driving wheel and the conveyor belt;

the driving motor rotates reversely, and the nth group of chucks are driven by the driving wheel and the conveyor belt to move along the lower chuck mounting track in the direction away from the 1 st group of chucks.

Optionally, the lower chuck mounting rail includes four guide rails arranged in a matrix, one of the two adjacent lower chucks is sleeved on the first group of diagonally opposite guide rails through a sleeve, and the other of the two adjacent lower chucks is sleeved on the second group of diagonally opposite guide rails through a sleeve.

Optionally, the membrane strip carrying device further comprises a mounting plate, the two sets of membrane strip carrying parts are fixed on the mounting plate, and the lower end of the mounting plate is slidably mounted on a sliding rail of the machine table through a sliding block.

Optionally, the film strip carrying device further comprises two jacking mechanisms, the two jacking mechanisms are respectively installed at the lower ends of the two groups of film strip carrying parts, and the two jacking mechanisms respectively drive the two groups of film strip carrying parts to lift.

Optionally, the membrane strip handling equipment still includes membrane strip stretch motor, flexible piece, first connecting rod and second connecting rod, wherein:

the telescopic block is positioned between the two groups of film strip conveying parts, and the first connecting rod and the second connecting rod are respectively connected between the telescopic block and the two groups of film strip conveying parts;

the driving end of the film strip stretching motor is connected with the telescopic block, the film strip stretching motor drives the telescopic block to move along the extending direction of the film strip carrying parts, and the first connecting rod and the second connecting rod drive the two groups of film strip carrying parts to be close to each other and to be away from each other under the driving of the telescopic block.

In a second aspect, the present application further provides a series welding film inserting apparatus, which includes a series welding apparatus, a conveying apparatus, a jacking apparatus, a heating device, and an in-line film inserting apparatus as provided in the first aspect and various alternatives of the first aspect, wherein:

the series welding equipment is used for series welding the battery pieces by using welding strips to form a battery string, wherein for any group of welding strips used for welding two adjacent battery pieces in the battery string, the front half section of each welding strip is welded on a grid line on the front side of the front battery piece in the two adjacent battery pieces, and the rear half section of each welding strip is welded on a grid line on the back side of the rear battery piece in the two adjacent battery pieces;

the conveying equipment conveys the battery string output by the string welding equipment to a film inserting station;

the film strip conveying device conveys the clamped n stretched film strips to the film inserting station and descends, so that the n film strips are opposite to the film inserting positions of the battery strings below up and down respectively;

the jacking equipment is positioned below the film inserting station and jacks each film inserting position in the battery string to form an opened film inserting space at each film inserting position;

the film strip conveying device inserts the n film strips into the corresponding film inserting spaces respectively;

the heating device is used for heating the film strip inserted into the film inserting space.

Optionally, the jacking device at least includes n jacking plates, and the n jacking plates jack up the battery piece at the corresponding jacking position to the conveyor belt of the conveying device.

Optionally, the series welding equipment includes welding and takes feedway, battery piece feedway, conveyor and welding set, wherein:

the welding strip feeding device is used for providing welding strips, and the battery piece feeding device is used for providing battery pieces;

the welding strip feeding device and the battery piece feeding device are matched with each other to stack battery pieces and welding strips on the conveying device;

the conveying device conveys the stacked battery pieces and the welding strips to a welding station, and the welding device positioned at the welding station welds the battery pieces and the welding strips to form a battery string.

Based on the technical characteristics, the application can at least realize the following beneficial effects:

the film cutting device is arranged to cut the film strip, and the film strip carrying device is arranged to pick up and carry the film strip obtained after cutting, so that the subsequent film inserting operation is facilitated, the manual participation is reduced, and the film strip generating and in-place efficiency is improved.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present invention and, together with the description, serve to explain the principles of the invention.

FIG. 1A is a schematic diagram of an in-line membrane insertion apparatus provided in one embodiment of the present application;

FIG. 1B is a schematic diagram of the structure of a film slitting device and a film strip handling device provided in one embodiment of the present application;

FIG. 2A is a schematic diagram of a film cutting apparatus provided in an embodiment of the present application;

FIG. 2B is a schematic diagram of a film supply apparatus provided in one embodiment of the present application;

FIG. 2C is a schematic view of a film supply apparatus provided in another embodiment of the present application;

FIG. 3A is a schematic view of a film strip handling apparatus provided in an embodiment of the present application;

FIG. 3B is a partial schematic view of the cartridge installed in the film strip handling apparatus provided in one embodiment of the present application;

FIG. 3C is a schematic view of the structure of a film strip handling apparatus provided in another embodiment of the present application;

fig. 3D is a top view of a film strip handling apparatus provided in yet another embodiment of the present application.

Wherein the reference numbers are as follows:

10. a film tape roll; 20. a film cutting device; 210. a film supply device; 211. the membrane strip passes through the bracket; 212. a first membrane tape bearing plate; 213. a second film tape bearing plate; 214. a first support plate driving mechanism; 215. a second support plate driving mechanism; 216. a membrane strip carrier plate; 217. a compression plate; 218. a pressing cylinder; 220. cutting the membrane assembly; 221. a first film tape holding section; 2221. mounting a plate; 2222. a film cutting chuck; 2223. a chuck lifting mechanism; 2224. a tension drive mechanism; 2225. mounting plates are arranged on the film cutting chucks; 2226. a lower mounting plate of the film cutting chuck; 2227. a lifting column; 222. a second film tape holding section; 223. a cutting section; 2231. hot shredding; 2232. a first connecting plate; 2233. a second connecting plate; 2234. a protection plate; 230. a film tape traction device; 231. a film tape traction chuck; 232. a chuck drive mechanism; 233. a traction movement mechanism; 30. a film strip handling device; 310. a chuck; 311. an upper chuck; 312. a lower chuck; 320. the lower chuck is provided with a track; 331. a drive motor; 332. a driving wheel; 333. a driven wheel; 334. a conveyor belt; 340. the upper chuck is provided with a track; 350. a first clamping action portion; 351. a connecting plate; 352. a sliding device; 353. a lifting cylinder; 360. a second clamping action portion; 361. a pressure lever; 362. a compression bar driving mechanism; 370. mounting a plate; 380. a jacking mechanism; 391. a film strip stretching motor; 392. a telescopic block; 393. a first link; 394. a second link; 40. a film tape.

Detailed Description

Reference will now be made in detail to the exemplary embodiments, examples of which are illustrated in the accompanying drawings. The following description refers to the accompanying drawings in which the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the invention, as detailed in the appended claims.

Fig. 1A is a schematic structural diagram of an in-line film inserting apparatus provided in an embodiment of the present application, and fig. 1B is a schematic structural diagram of a film cutting device and a film strip conveying device provided in an embodiment of the present application, and in combination with fig. 1A and 1B, the in-line film inserting apparatus provided in the present application may include a film tape roll 10, a film cutting device 20, and a film strip conveying device 30, wherein: the film tape roll 10 is used for carrying a film tape roll; the film cutting device 20 cuts the film strip drawn from the film strip material roll 10 to obtain n film strips; the film strip carrying device 30 clamps n film strips from the film cutting device 20, separates the n film strips at preset intervals, synchronously moves the n film strips to the corresponding film inserting stations in the battery string, and inserts films, wherein the preset intervals are the intervals between two adjacent film inserting stations in the battery string.

In some embodiments of the present application, the film strip may be stretched by the film cutting device 20, in which case the film cutting device 20 may be configured to stretch the n cut film strips, and the film strip handling device 30 holds the n stretched film strips from the film cutting device 20; alternatively, the film strip may be stretched by the film strip transporting device 30, and in this case, the film strip transporting device 30 may clamp n film strips from the film slitting device 20 and then stretch the n film strips before film insertion.

In some embodiments, the film strip drawing can be performed by the film cutting device 20 or the film strip handling device 30, in a first manner, the film cutting device 20 draws the film strip from the film strip roll 10, and cuts the drawn film strip; in the second mode, the film strip conveying device 30 draws the film strip from the film strip roll 10 and passes through the film cutting device 20, and the film cutting device 20 cuts the film strip passing through the film cutting device 20.

Referring to fig. 2A, which is a schematic structural diagram of a film cutting apparatus provided in an embodiment of the present application, the film cutting apparatus 20 provided in the present application may include a film supply apparatus 210 and a film cutting assembly 220.

In actual production, the film supplying device 210 is used for supplying the film strip 40, the film strip is drawn out from the film supplying device 210 and passes through the clamping film cutting channel of the film cutting assembly 220, and the film cutting assembly 220 cuts and forms a film strip after clamping two sides of the film strip 40 passing through the clamping film cutting channel.

The film cutting assembly 220 provided herein may include at least a first film strip holder 221, a second film strip holder 222, and a cutter 223. Optionally, the first film strip clamping portion 221 and the second film strip clamping portion 222 are arranged at intervals, and the width between the first film strip clamping portion and the second film strip clamping portion is adapted to the width of the film strip 40, so as to clamp two side edges of the film strip 40 respectively.

In a possible implementation manner, the film cutting device 20 has a film tape drawing function, in which case the film cutting device 20 may further include a film tape drawing device 230, and the film tape drawing device 230 draws the film tape 40 from the film supply device 210 and draws the film tape through the clamping film cutting channel of the film cutting assembly 220. That is, the film tape drawing device 230 draws the film tape 40 from the film supply device 210 and then draws the drawn end of the film tape 40 through the holding film cutting passage of the film cutting assembly 220.

The first film tape clamping portion 221 and the second film tape clamping portion 222 clamp both side edges of the film tape 40 passing through the clamping and film cutting channel, respectively, and the clamped film tape 40 is cut by the cutting portion 223 to obtain a film strip.

In a possible implementation manner, the film cutting device 20 has a film strip stretching function, and the first film strip clamping part 221 and the second film strip clamping part 222 can also be configured to be far away from each other along the horizontal direction so as to stretch the clamped cut film strip.

Referring to fig. 2B and 2C, the film feeding device 210 provided by the present application may include at least a film tape passing support 211, a first film tape support plate 212, a second film tape support plate 213, a first support plate driving mechanism 214, and a second support plate driving mechanism 215. The film tape 40 supplied from the film tape roll 10 is drawn out through the film tape passing holder 211.

The discharge port of the membrane strip passing bracket 211 is positioned at the feed port of the clamping and membrane cutting channel, and the pulled membrane strip 40 enters the clamping and membrane cutting channel from the membrane strip passing bracket 211.

The film tape passing bracket 211 is provided for buffering the film strip drawn out from the film tape roll and guiding the film tape to the clamping and film cutting channel. In practical application, at least part of the film tape passing bracket 211 can be provided with two parallel passing strips, the gap between the two parallel passing strips is slightly larger than the thickness of the film tape, and the film tape roll passes through the two passing strips, so that the curling of the film tape roll in the traction process is avoided.

The first film tape supporting plate 212 and the second film tape supporting plate 213 are respectively located at both sides of the clamping and film cutting passage, and respectively vertically cooperate with the first film tape clamping portion 221 and the second film tape clamping portion 222 to clamp the film tape 40.

The first and second support

plate driving mechanisms

214 and 215 respectively drive the first and second film

strip support plates

212 and 213 to move away from each other, so as to stretch the two ends of the clamped film strip.

In the present application, the first film tape supporting plate 212 and the second film tape supporting plate 213 are symmetrically, horizontally and oppositely disposed, the first film tape supporting plate 212 and the first film tape clamping portion 221 are disposed up and down oppositely, and the second film tape supporting plate 213 and the second film tape clamping portion 222 are disposed up and down oppositely.

In order to ensure the cutting quality of the film strip 40 when being cut, in practical applications, before the film strip 40 clamping and cutting the film channel is cut, the position of the film strip at the inlet of the clamping and cutting film channel can be pressed, and correspondingly, the film supply device 210 provided by the present application may further include a film strip bearing plate 216, a pressing plate 217 and a pressing cylinder 218.

The film strip bearing plate 216 is positioned between the discharge opening of the film strip passing bracket 211 and the feed opening of the clamping film cutting channel so as to bear the film strip 40 pulled out from the film strip passing bracket 211.

The pressing plate 217 is located above the film strip bearing plate 216, the driving end of the pressing cylinder 218 is fixedly connected with the pressing plate 217, and the pressing cylinder 218 drives the pressing plate 217 to move towards the film strip bearing plate 216 so as to press the film strip 40 at the film strip bearing plate 216.

In order to ensure that the film strip can be cut successfully, in practical applications, the first film strip supporting plate 212 and the second film strip supporting plate 213 are used for supporting the upper end face of the film strip and are provided with avoidance grooves opposite to the cutting wires. In this way, the cutting filaments can be cut downward above the film strip 40 and into the escape slots, completing the cutting of the film strip 40.

In an alternative implementation, still referring to fig. 2A, the first film strip holding portion 221 and the second film strip holding portion 222 have the same structure, and the first film strip holding portion 221 may include a mounting plate 2221, a film cutting clamp 2222 mounted on the mounting plate 2221, a clamp lifting mechanism 2223, and a stretching driving mechanism 2224, wherein:

the film cutting chuck 2222 is in transmission connection with the chuck lifting mechanism 2223 and the stretching driving mechanism 2224 respectively, the chuck lifting mechanism 2223 drives the film cutting chuck 2222 to descend so as to press the film strip 40 passing through the film clamping and cutting channel, and the stretching driving mechanism 2224 drives the film cutting chuck 2222 to move in a direction away from the center line of the film clamping and cutting channel and horizontally, vertically and outwards so as to stretch the clamped film strip 40.

The mounting plate 2221 is located outside the slit film cartridge 2222 and is fixed in position relative to the holding slit film channel.

The number of the film cutting chucks 2222 in this application may be at least two, and at least two film cutting chucks 2222 are arranged side by side, and generally speaking, the number of the film cutting chucks 2222 is the same as the number of some film strips obtained by cutting the film, and each film cutting chuck 2222 holds the side edge of one film strip.

The film cutting chucks 2222 on the first film strip clamping portion 221 and the second film strip clamping portion 222 are arranged oppositely one by one, and the oppositely arranged groups of film cutting chucks 2222 are respectively used for clamping two sides of one film strip.

Optionally, the first membrane strip holder 221 may further include a membrane cutting chuck upper mounting plate 2225, a membrane cutting chuck lower mounting plate 2226, and a lifting column 2227, wherein:

the membrane cutting chuck upper mounting plate 2225 is mounted on the membrane cutting chuck lower mounting plate 2226 by a lifting column 2227.

The upper end of the film cutting chuck 2222 is fixed to the upper film cutting chuck mounting plate 2225, and the lower pressing surface of the film cutting chuck 2222 is lower than the lower film cutting chuck mounting plate 2226. It will be appreciated that the pressing surface of the film cutting cartridge 2222 is mounted through the film cutting cartridge lower mounting plate 2226 to ensure that the pressing surface of the film cutting cartridge 2222 can grip the film strip 40 holding the corresponding position of the film cutting passageway.

The driving end of the chuck lifting mechanism 2223 is fixedly connected with the upper film cutting chuck mounting plate 2225 so as to drive the upper film cutting chuck mounting plate 2225 to lift relative to the lower film cutting chuck mounting plate 2226.

Optionally, the driving end of the stretching driving mechanism 2224 is fixedly connected to the lower film cutting chuck mounting plate 2226, so that the lower film cutting chuck mounting plate 2226 drives the film cutting chuck 2222 to move in a direction away from the center line of the film clamping and cutting channel and horizontally, vertically and outwardly. That is, the stretching driving mechanism 2224 in the first film tape holding section 221 and the stretching driving mechanism 2224 in the second film tape holding section 222 are simultaneously away from each other, and stretching of the film tape 40 in the holding slit film passage is achieved.

In practical applications, the film strip 40 is usually made of a soft material, and in order to realize cutting of the film strip 40, improve cutting efficiency, and ensure cutting quality, the cutting portion 223 provided in the present application may include at least one hot filament 2231, a first connecting plate 2232, a second connecting plate 2233, a first lifting driving portion, and a second lifting driving portion, where the hot filament 2231 realizes cutting of the film strip 40 through high temperature.

For any one of the hot wires 2231, both ends of the hot wire 2231 are mounted on the first connecting plate 2232 and the second connecting plate 2233, respectively. That is, both ends of the group of hot cut wires 2231 are respectively installed on the first connecting plate 2232 and the second connecting plate 2233, and in order to ensure that the widths of the plurality of film strips to be cut are uniform, the hot cut wires 2231 are generally disposed at an equal distance from each other, and the distance between two adjacent cut wires is the same as the width of the film strip to be cut.

In a possible implementation, in order to avoid safety problems caused by overheating of the hot wire 2231, a protection plate 2234 may be fixed between the first connecting plate 2232 and the second connecting plate 2233, and the hot wire 2231 may be disposed below the protection plate 2234 or inside the protection plate 2234.

The driving end of the first lifting driving part is connected with the first connecting plate 2232, the driving end of the second lifting driving part is connected with the second connecting plate 2233, and the first lifting driving part and the second lifting driving part are matched to drive the first connecting plate 2232 and the second connecting plate 2233 to lift so as to drive the hot cutting wire 2231 to lift.

Wherein the hot-cut 2231 extends in a direction perpendicular to the direction of the draw of the film strip 40.

First lift drive division and the cooperation of second lift drive division drive first connecting plate 2232 and the lift of second connecting plate 2233 can guarantee that many hot filament 2231 cut film tape 40 simultaneously, have improved cutting efficiency greatly.

When the film cutting device 20 has a film tape drawing function, as shown in fig. 2A, the film tape drawing device 30 provided by the present application may include at least a film tape drawing chuck 231, a chuck driving mechanism 232, and a drawing moving mechanism 233.

The traction moving mechanism 233 is in transmission connection with a traction chuck, and the driving end of the chuck driving mechanism 232 is connected with the traction chuck; the drawing and moving mechanism 233 drives at least the drawing chuck to the film supply device 210, and the chuck driving mechanism 232 drives the drawing chuck to clamp the film tape 40 at the film supply device 210.

In a possible implementation manner, at least two film strip pulling chucks 231 may be arranged side by side according to the width of the film strip 40, and the at least two film strip pulling chucks 231 are arranged at regular intervals and configured to simultaneously hold the ends of the film strip 40 to ensure flatness when the film strip 40 is pulled.

Fig. 3A is a schematic structural diagram of a film strip carrying device provided in an embodiment of the present application, and the film strip carrying device 30 provided in the present application may include at least two sets of film strip carrying portions that are oppositely disposed, where the two sets of film strip carrying portions respectively clamp two ends of n film strips, and for each set of film strip carrying portion, the film strip carrying portion includes n sets of chucks 310, a lower chuck mounting rail 320, and a driving mechanism.

Generally speaking, two sets of membrane strip transport portions's structure is the same, all is provided with n group's chuck 310 on every group membrane strip transport portion, and the chuck 310 one-to-one on two sets of membrane strip transport portions cooperates the both ends of the same membrane strip of centre gripping. In other words, the ith clamping head 310 on the first group of film strip conveying parts and the ith clamping head 310 on the second group of film strip conveying parts are matched to respectively clamp the two ends of the ith film strip.

Each set of the chucks 3310 includes an upper chuck 11 and a lower chuck 312 for holding the film strip, which are opposite to each other, and the lower chuck 12 of each set of the chucks 3310 is mounted on the lower chuck mounting rail 320, and a driving mechanism is drivingly connected to the n chucks 310, and drives the n sets of the chucks 310 to move along the lower chuck mounting rail 320.

In an actual application scenario, the distance between the n film strips at the film strip feeding station is small, and the distance between the film strips required at the film inserting station is large, so when the n groups of chucks 310 pick up the n film strips, the distance between the n film strips is usually required to be adjusted to ensure that the distance between the film strips meets the requirement of the film inserting distance. And the spacing adjustment between the n sets of collets 310 is also required to meet the pick-up spacing requirements for the n film strips at the film strip feed station. Therefore, the driving mechanism in the present application can drive the n groups of chucks 310 to move along the lower chuck mounting rail 320, and can adjust the distance between the n groups of chucks 310.

In order to realize the distance adjustment between the n groups of the chucks 310, in one possible implementation manner, the 2 nd to nth lower chucks 312 are movably mounted on the lower chuck mounting rail 320, and the groups of the chucks 310 are connected to each other through a flexible member.

The 1 st group of chucks 310 are fixedly mounted, that is, the upper chuck 311 and the lower chuck 312 of the 1 st group of chucks 310 are both fixedly mounted, the nth group of chucks 310 are in transmission connection with a driving mechanism through a connecting piece, and when the driving mechanism drives the nth group of chucks 310 to move along the lower chuck mounting rail 320, the driving mechanism drives the groups of chucks 310 to mutually approach and mutually separate through a flexible piece so as to adjust the distance between n clamped film strips.

In order to achieve the clamping and expanding between the upper clamping head 311 and the lower clamping head 312, at least two mounting manners of the clamping head 310 are provided, which can be seen in fig. 3B and 3C, respectively.

Fig. 3B is a partial schematic view of the film strip conveying device provided in an embodiment of the present application when the chucks are installed, with reference to fig. 3A and 3B, the film strip conveying portion provided in the present application may further include an upper chuck mounting rail 340, the tail portion of each upper chuck 311 is mounted on the upper chuck mounting rail 340, the middle portions of each set of upper chuck 311 and lower chuck 312 are connected by a pin, the film strip conveying portion may further include first clamping action portions 350 mounted at two ends of the upper chuck mounting rail 340, the two first clamping action portions 350 act synchronously to drive the upper chuck mounting rail 340 to ascend or descend together, when the upper chuck mounting rail 340 ascends, the tail end of each upper chuck 311 is driven to ascend, and the clamping portions of each upper chuck 311 rotate around the corresponding rotation shafts to press against the clamping portions of the corresponding lower chuck 312.

Still referring to fig. 3B, in order to achieve the clamping action between the upper and

lower chucks

311 and 312, the first clamping action portion 350 may include a connection plate 351, a sliding device 352, and a lifting cylinder 353, wherein:

the connecting plate 351 is mounted on the sliding means 352. The sliding device 352 may include a slider, a sliding driver, a sliding rail, and the like, wherein the connecting plate 351 is mounted on the sliding rail through the slider, and the sliding driver drives the connecting plate 351 to move along the sliding rail.

The end of the upper chuck mounting rail 340 passes through the connecting plate 351 and is connected to the driving end of the lifting cylinder 353.

The lifting cylinder 353 drives the upper chuck mounting rail 340 to ascend along the sliding device 352, so as to drive the mounting portions of the upper chucks 311 on the upper chuck mounting rail 340 to ascend, further drive the clamping portions of the upper chucks 311 to move around the rotating shaft toward the corresponding clamping portions of the lower chucks 312, and realize clamping of the chucks.

The lifting cylinder 353 drives the upper chuck mounting rail 340 to descend along the sliding device 352, so as to drive the mounting portions of the upper chucks 311 on the upper chuck mounting rail 340 to descend, and further drive the clamping portions of the upper chucks 311 to move away from the corresponding clamping portions of the lower chucks 312 around the rotating shaft, thereby realizing the opening of the chucks 310.

Fig. 3C is a schematic structural diagram of a film strip handling apparatus provided in another embodiment of the present application, in the embodiment shown in fig. 3C, a tail portion of the upper clamp 311 and a tail portion of the lower clamp 312 of each set of clamps 310 provided in the present application are connected by a spring, a middle portion of the upper clamp 311 and the lower clamp 312 of each set of clamps 310 is mounted by a pin, the film strip handling apparatus further includes a second clamping action portion 360, the second clamping action portion 360 includes a pressing rod 361 and a pressing rod driving mechanism 362, wherein:

the driving end of the pressing rod driving mechanism 362 is connected with the pressing rods 361, and the pressing rods 361 are arranged above the tail parts of the upper chucks 311.

The pressing rod driving mechanism 362 drives the pressing rods 361 downwards, and the pressing rods 361 press the tail parts of the upper clamping heads 311 to the tail parts of the corresponding lower clamping heads 312, so that the clamping heads 310 are opened.

The pressing rod driving mechanism 362 drives the pressing rods 361 upwards, the pressing rods 361 are far away from the tail parts of the upper clamping heads 311, and the tail parts of the upper clamping heads 311 are separated from the tail parts of the lower clamping heads 312 under the action of the corresponding springs, so that the clamping of the clamping heads 310 is realized.

Still referring to fig. 3A, to accomplish driving of the n groups of chucks 310, the driving mechanism provided by the present application may include a driving motor 331, a driving wheel 332, a driven wheel 333, and a transmission belt 334.

The driving wheel 332 and the driven wheel 333 are respectively installed at two ends of the installation clamp where the lower chuck installation rail 320 is located, the transmission belt is sleeved on the driving wheel 332 and the driven wheel 333, the nth group of chucks 310 are fixed on the transmission belt 334 through a connecting piece, and the driving end of the driving motor 331 is in transmission connection with the driving wheel 332.

The driving motor 331 rotates forward, and drives the nth group of chucks 310 to move towards the direction close to the 1 st group of chucks 310 along the lower chuck mounting rail 320 through the driving wheel 332 and the conveyor belt 334; the driving motor 331 rotates in a reverse direction, and the nth set of chucks 310 are moved along the lower chuck mounting rail 320 in a direction away from the 1 st set of chucks 310 by the driving wheel 332 and the conveyor belt 334. The angle of rotation and the number of rotations of the drive motor 331 determine the amount of spacing between the n sets of jaws 310.

In a possible implementation manner, when it is ensured that the chucks 310 can smoothly move on the lower chuck mounting rail 320, in order to further ensure that the adjacent chucks 310 can approach each other to clamp the film strip with a smaller distance, the lower chuck mounting rail 320 provided by the present application may further include four guide rails arranged in a matrix, one of the two adjacent lower chucks 312 is sleeved on the first set of diagonally opposite guide rails through a sleeve, and the other of the two adjacent lower chucks 312 is sleeved on the second set of diagonally opposite guide rails through a sleeve.

The film strip carrying device 30 may further include a mounting plate 370, the two sets of film strip carrying portions are fixed on the mounting plate 370, and the lower end of the mounting plate 370 is slidably mounted on the slide rail of the machine platform through a slider.

The film strip carrying device 30 can further comprise two jacking mechanisms 380, the two jacking mechanisms 380 are respectively installed at the lower ends of the two groups of film strip carrying parts, and the two jacking mechanisms 380 respectively drive the two groups of film strip carrying parts to lift.

In a possible implementation manner, the film strip carrying device 30 provided in the present application may further implement stretching of the clamped and carried film strip, as shown in fig. 3D, which is a top view of the film strip carrying device provided in another embodiment of the present application, and the film strip carrying device 30 provided in the present application may further include a film strip stretching motor 391, a telescopic block 392, a first connecting rod 393 and a second connecting rod 394.

The expansion block 392 is located between the two sets of film strip carrying portions, and the first link 393 and the second link 394 are connected between the expansion block 392 and the two sets of film strip carrying portions, respectively, that is, the first link 393 is connected between the expansion block 392 and the first set of film strip carrying portions, and the second link 394 is connected between the expansion block 392 and the second set of film strip carrying portions.

The driving end of the film strip stretching motor 391 is connected with the stretching block 392, the stretching block 392 is usually installed on a slide rail which is located in front of the two groups of film strip carrying parts and is consistent with the extending direction of the two groups of film strip carrying parts, the film strip stretching motor 391 drives the stretching block 392 to move along the slide rail, correspondingly, the first connecting rod 393 and the second connecting rod 394 drive the two groups of film strip carrying parts to approach each other and to move away from each other under the driving of the stretching block 392. When two sets of membrane strip transport portions kept away from each other, realized the drawing between the membrane strip that two sets of membrane strip transport portions held.

To sum up, the online membrane equipment of inserting that this application provided realizes cutting the membrane area through setting up the membrane cutting device, through setting up membrane strip handling device, realizes picking up and the transport of the membrane strip that obtains after cutting, and the subsequent membrane operation of inserting of being convenient for has reduced artifical participation, has improved membrane strip and has generated and the efficiency that targets in place.

The application also provides series welding film inserting equipment which comprises series welding equipment, conveying equipment, jacking equipment, a heating device and online film inserting equipment, wherein the structure of the online film inserting equipment can be described in the figures 1A-3D, and the details are not repeated here.

The series welding equipment is used for series welding the battery pieces by utilizing the welding strip to form the battery string, wherein for any group of welding strips used for welding the adjacent two battery pieces in the battery string, the front half section of the welding strip is welded on the grid line on the front side of the front battery piece in the adjacent two battery pieces, and the rear half section of the welding strip is welded on the grid line on the back side of the rear battery piece in the adjacent two battery pieces.

And the conveying equipment conveys the battery string output by the string welding equipment to a film inserting station.

The film strip carrying device conveys the clamped n stretched film strips to the film inserting station and descends, so that the n film strips are respectively opposite to the film inserting positions of the battery strings below.

The jacking equipment is positioned below the film inserting station, and each film inserting position in the jacking battery string is positioned on the rear battery piece, so that an opened film inserting space is formed at each film inserting position.

The film strip conveying device inserts the n film strips into the corresponding film inserting spaces respectively. In an alternative mode, the film strip conveying device can simultaneously insert n film strips into the corresponding film inserting spaces respectively so as to improve the film inserting efficiency. For example, after the film strip conveying device separates n film strips and respectively corresponds to each film inserting space, the film strip conveying device controls the two film strip conveying parts to simultaneously convey the n clamped film strips forwards so as to respectively and correspondingly insert the n film strips into the film inserting spaces, and the simultaneous insertion of the n film strips is completed.

The heating device heats the film strip inserted into the film inserting space.

In order to realize that the multiunit jacking is inserted membrane efficiency in order to improve the jacking, the jacking equipment that this application provided can include n jacking boards at least, and n jacking boards will correspond the battery piece jacking of jacking position department and rise in conveying equipment's conveyer belt.

In one possible implementation manner, the series welding apparatus provided by the present application may include a solder strip feeding device, a battery piece feeding device, a conveying device, and a welding device, wherein: the welding strip feeding device is used for providing welding strips, and the battery piece feeding device is used for providing battery pieces; the welding strip feeding device and the battery piece feeding device are matched to stack the battery pieces and the welding strips to the conveying device; and the conveying device conveys the stacked battery pieces and the welding strips to a welding station, and the welding device positioned at the welding station welds the battery pieces and the welding strips to form a battery string.

To sum up, the series welding inserts membrane equipment that this application provided integrates through inserting membrane equipment with series welding equipment on line, has realized inserting the membrane on line to the battery cluster of series welding equipment output, inserts membrane efficiently, and has saved the overall arrangement space of production facility.

Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice within the art to which the invention pertains. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.

It will be understood that the invention is not limited to the precise arrangements described above and shown in the drawings and that various modifications and changes may be made without departing from the scope thereof. The scope of the present invention is limited only by the appended claims.

Claims

1. An online film inserting device, which is characterized by comprising a film tape roll, a film cutting device and a film strip conveying device, wherein:

the film tape roll is used for carrying a film tape roll;

the film cutting device is used for cutting the film tape drawn from the film tape roll to obtain n film strips;

the film strip handling device is configured to clamp the n film strips from the film cutting device, separate the n film strips at a preset interval and synchronously move the n film strips to corresponding film inserting stations in a battery string for film inserting, wherein the preset interval is the distance between two adjacent film inserting stations in the battery string.

2. The on-line film inserting equipment as claimed in claim 1, wherein the film cutting device is further configured to stretch n cut films, and the film strip handling device is configured to clamp the n stretched films from the film cutting device;

or,

the film strip conveying device is used for clamping the n film strips from the film cutting device and then stretching the n film strips before film insertion.

3. The on-line film inserting equipment as claimed in claim 1, wherein the film cutting device is used for drawing a film strip from the film strip material roll and cutting the drawn film strip;

or,

the film strip handling device is configured to pull a film strip from the film strip roll and pass through the film cutting device, and the film cutting device is used for cutting the film strip passing through the film cutting device.

4. The on-line film inserting equipment according to claim 1, wherein the film cutting device comprises a film supplying device and a film cutting assembly, and the film cutting device comprises a first film strip clamping part, a second film strip clamping part and a cutting part, wherein:

the film belt is configured to pass through the clamping film cutting channel of the film cutting assembly after being drawn out of the film supply device;

the first film strip clamping part and the second film strip clamping part are respectively configured to clamp two side edges of the film strip passing through the clamping and film cutting channel, and the clamped film strip is cut by the cutting part to obtain a film strip.

5. The on-line film inserting equipment according to claim 4, wherein the film cutting device further comprises a film tape traction device, and the film tape traction device is used for drawing a film tape from the film supply device and passing through the clamping film cutting channel of the film cutting assembly.

6. The on-line film inserting equipment according to claim 4, wherein the first film strip clamping part and the second film strip clamping part are identical in structure, the first film strip clamping part comprises a mounting plate, and a film cutting chuck, a chuck lifting mechanism and a stretching driving mechanism which are mounted on the mounting plate, wherein:

the film cutting chuck is in transmission connection with the chuck lifting mechanism and the stretching driving mechanism respectively, the chuck lifting mechanism is used for driving the film cutting chuck to descend so as to press the film belt passing through the clamping and film cutting channel, and the stretching driving mechanism is used for driving the film cutting chuck to move towards the direction which is far away from the central line of the clamping and film cutting channel and is horizontally, vertically and outwards so as to stretch the clamped film belt;

7. The on-line film inserting device according to claim 6, wherein the first film strip clamping part further comprises an upper film cutting chuck mounting plate, a lower film cutting chuck mounting plate and a lifting column, wherein:

8. The on-line film inserting equipment according to claim 1, wherein the film strip conveying device comprises two sets of film strip conveying parts which are oppositely arranged and respectively clamp two ends of n film strips, and for each set of film strip conveying part, the film strip conveying part comprises n sets of chucks, a lower chuck mounting rail and a driving mechanism, wherein:

9. The on-line film inserting equipment according to claim 8, wherein the 2 nd to the nth lower chucks are movably mounted on the lower chuck mounting rail, and the chucks in each group are connected with each other through a flexible member;

the 1 st group chuck fixed mounting, the nth group chuck pass through the connecting piece with actuating mechanism transmission is connected, actuating mechanism drives nth group chuck along lower chuck installation track removes, through the flexible piece drives and is close to each other and keep away from each other between each group chuck to adjust the interval of n membrane strips of centre gripping.

10. The on-line film inserting equipment according to claim 9, wherein the film strip conveying part further comprises an upper chuck mounting rail, each upper chuck is mounted on the upper chuck mounting rail, the middle part of each upper chuck and the middle part of each lower chuck are connected through a pin, the film strip conveying part further comprises first clamping action parts mounted at two ends of the upper chuck mounting rail, the two first clamping action parts act synchronously to drive the upper chuck mounting rail to ascend or descend together, when the upper chuck mounting rail ascends, the tail end of each upper chuck is driven to ascend, and the clamping part of each upper chuck rotates around the corresponding rotating shaft to press against the clamping part of the corresponding lower chuck.

11. The apparatus according to claim 9, wherein the rear ends of the upper and lower chucks of each set of chucks are connected by a spring, the middle portions of the upper and lower chucks of each set of chucks are mounted on the rotary shaft, the film strip carrying portion further comprises a second clamping action portion, the second clamping action portion comprises a pressing rod and a pressing rod driving mechanism, and wherein:

12. The on-line film inserting apparatus according to claim 8, wherein the film strip carrying apparatus further comprises a film strip stretching motor, a telescopic block, a first link and a second link, wherein:

13. A series welding film inserting apparatus, comprising a series welding apparatus, a conveying apparatus, a jacking apparatus, a heating device and the on-line film inserting apparatus according to any one of claims 1 to 12, wherein:

the conveying equipment is used for conveying the battery string output by the series welding equipment to a film inserting station;

the film strip conveying device is used for conveying the clamped n stretched film strips to the film inserting station and descending the film strips so that the n film strips are respectively opposite to each film inserting position of the battery string below the film strip;

the jacking equipment is positioned below the film inserting station and used for jacking the rear battery piece at each film inserting position in the battery string to enable each film inserting position to form an opened film inserting space;

the film strip conveying device is used for respectively inserting the n film strips into the corresponding film inserting spaces;

14. The series welding and film inserting equipment as claimed in claim 13, wherein the jacking equipment at least comprises n jacking plates, and the n jacking plates jack the battery piece at the corresponding jacking position to the conveying belt of the conveying equipment.

15. The series welding and film inserting device according to claim 14, wherein the series welding device comprises a welding strip feeding device, a battery piece feeding device, a conveying device and a welding device, wherein:

the welding strip feeding device and the battery piece feeding device are configured to be matched with the conveying device to stack battery pieces and welding strips;

the conveying device is used for conveying the stacked battery plates and the welding strips to a welding station, and the welding device positioned at the welding station is used for welding to form a battery string.