Patent Description:
A battery housing and an end cover are generally fixed by welding. Before welding, the end cover needs to be pressed to align with a reference plate through a pressing device and riveted into an opening of the housing, so that a top face of the end cover is flush with a top face of the housing, and then the housing is clamped through a clamping device from all sides to ensure the reliability of subsequent welding. However, the inventors found that in an actual process, due to the inaccuracy of a clamping position and a clamping force, welding failure or poor welding of a battery housing and an end cover often occurs, which results in the scrapping of a battery.

Document <CIT> discloses an automatic press-in and welding equipment for thermal battery covers.

In view of the above problems, the present application provides a battery assembly assembling method, a clamp and a welding device to solve the problem that a clamping position and a clamping force of a battery assembly cannot be determined.

According to one aspect of an embodiment of the present application, provided is a battery assembly assembling method according to claim <NUM>.

In the present application, on the one hand, after determining that an absolute value of a difference between an actual pressing displacement amount and a preset standard pressing displacement amount is less than or equal to a preset pressing threshold, a clamping operation is then performed to ensure that a welding surface of a battery assembly is aligned with a reference plane so that a defocusing amount of the welding meets requirements and welding effect is ensured. On the other hand, in the clamping operation, by simultaneously determining an absolute value of a difference between a first actual displacement amount and a preset first standard displacement amount is less than or equal to a preset first displacement threshold, and an absolute value of a difference between a first clamping force and a preset first standard clamping force is less than or equal to a preset first clamping force threshold, it not only ensures that a displacement amount of a clamping device meets requirements, and at the same time, it also ensures that a clamping force applied to the battery assembly also meets requirements, thereby ensuring that there will be no errors in production sizes of the battery assembly, and welding seams that do not meet requirements, which can effectively avoid situations such as welding failure and scrapping of the battery assembly.

When the absolute value of the difference between the actual pressing displacement amount and the preset standard pressing displacement amount is greater than the preset pressing threshold, the pressing device is controlled to be reset and press downward again, which can quickly eliminate the situation that the pressing displacement amount is not up to standard caused by some accidental reasons of the pressing device or structure, and reduce the time cost of assembling.

In an optional manner, if the absolute value of the difference between the first actual displacement amount and the preset first standard displacement amount is greater than the preset first displacement threshold, the clamping device is controlled to be reset and perform clamping again. The situation that the clamping displacement amount is not up to standard due to some accidental reasons of the clamping device or structure can be quickly eliminated, and the time cost of assembling can be reduced.

In an optional manner, if the absolute value of the difference between the first clamping force and the preset first standard clamping force is greater than the preset first clamping force threshold, the clamping device is controlled to be reset and perform clamping again. The situation that the clamping force is not up to standard due to some accidental reasons in the clamping device or structure can be quickly eliminated, and the time cost of assembling can be reduced.

In an optional manner, the method further includes: controlling the clamping device to clamp the battery assembly from a second side face of the battery assembly that is adjacent to the first side face; acquiring a second actual displacement amount of the clamping device and a second clamping force of the clamping device clamping the second side face of the battery assembly; detecting the second actual displacement amount and the second clamping force; and completing the assembling if an absolute value of a difference between the second actual displacement amount and a preset second standard displacement amount is less than or equal to a preset second displacement threshold, and an absolute value of a difference between the second clamping force and a preset second standard clamping force is less than or equal to a preset second clamping force threshold. By adding the step of controlling the clamping device to clamp the battery from the second side face of the battery assembly, and detecting the second actual displacement amount and the second clamping force, it can ensure that the battery assembly is fully clamped all around, and further ensure that all points of a welding seam between an end cover and a housing of the battery assembly meet welding requirements, ensure success rate of welding, and improve welding effect.

According to another aspect of an embodiment of the present application, provided is a battery assembly clamp according to claim <NUM>.

By disposing the first feedback unit on the pressing device, the first feedback unit is configured to detect the actual pressing displacement amount of the pressing device moving downward and send the actual pressing displacement amount to the control unit so as to realize precise positioning of the battery assembly. By disposing the second feedback unit on the clamping device, the second feedback unit is configured to detect the first actual displacement amount and the first clamping force of the clamping device and send the first actual displacement amount and the first clamping force to the control unit so as to ensure the accuracy of the clamping position and clamping force of the clamping device for the battery assembly, and further ensure that conditions such as a defocusing amount and a welding seam during the subsequent welding of the battery assembly meet requirements.

In an optional manner, the first feedback unit includes a displacement sensor. By setting the first feedback unit as a displacement sensor, it can effectively ensure the accurate measurement of the pressing displacement amount of the pressing device, thereby ensuring that a defocusing amount between a welding plane and a welding head of the battery assembly meet requirements, and ensuring success rate of welding.

In an optional manner, a carrying platform for placing the battery assembly is disposed in the clamping device, a bottom of the carrying platform is connected to the clamping device through a first elastic member, and the first elastic member is configured to provide an upward elastic force for the carrying platform. The bottom of the carrying platform is connected to the clamping device through the first elastic member, and the first elastic member is configured to provide an upward elastic force for the carrying platform, which on the one hand ensures the stability of the battery assembly when it is placed on the carrying platform, and on the other hand, ensures that when the battery assembly is discharged, the battery assembly can be sent out from the top of the clamping device through the first elastic member.

In an optional manner, a restraint plate is disposed in the clamping device, a movable first clamping plate is disposed at a position opposite to the restraint plate in the clamping device, and the first clamping plate is configured to clamp the battery assembly from the first side face of the battery assembly when the first clamping plate moves, so that the battery assembly is clamped between the first clamping plate and the restraint plate. By disposing the restraint plate in the clamping device, and setting the movable first clamping plate at a position opposite to the restraint plate, the battery assembly can be firmly clamped between the first clamping plate and the restraint plate when the first clamping plate moves.

In an optional manner, the second feedback unit includes an electric cylinder, and the electric cylinder is connected to the first clamping plate for driving the first clamping plate to move. By setting the second feedback unit as an electric cylinder, and the electric cylinder to be connected to the first clamping plate, not only the driving of the first clamping plate is realized, but also detection and feedback of the first actual displacement amount of the first clamping plate as well as the first clamping force of the first clamping plate for the battery assembly can be realized.

In an optional manner, the first clamping plate is connected to the electric cylinder through a second elastic member, so that the first clamping plate is able to be tilted against the first side face of the battery assembly. The first clamping plate is connected to the electric cylinder through the second elastic member so that the first clamping plate is able to be tilted to a certain extent. If the first side face of the battery assembly is tilted to a certain extent due to production reasons, the first clamping plate moves and contacts the first side face of the battery assembly so as to clamp the battery assembly, the first clamping plate is able to be tilted correspondingly with the tilting of the first side face, so that the first clamping plate exerts the more uniform clamping force on the first side face of the battery assembly, and exhibits an ability of self-adaptive adjustment for clamping the battery assembly to ensure the reliability of clamping.

In an optional manner, a movable second clamping plate is further disposed in the clamping device, and the second clamping plate is configured to clamp the battery assembly from a second side face of the battery assembly that is adjacent to the first side face when the second clamping plate moves. By disposing the movable second clamping plate in the clamping device, the second clamping plate is configured to clamp the battery assembly from the second side face of the battery assembly that is adjacent to the first side face when the second clamping plate moves, so as to clamp the battery assembly completely and fully, thereby ensuring that a welding seam on a welding plane of the battery assembly meets requirements and ensuring success rate of welding.

In an optional manner, both the restraint plate and the first clamping plate are able to move in a moving direction of the second clamping plate. By setting the restraint plate and the first clamping plate to be able to move in the moving direction of the second clamping plate, it ensures that when the second clamping plate moves and clamps the battery assembly, the first clamping plate and the restraint plate can move with the battery assembly to prevent friction between the battery assembly and the first clamping plate and the restraint plate, so as not to cause abrasion or even damage to the surface of the battery assembly.

The control unit is configured to: detect an actual pressing displacement amount; control the clamping device to clamp the battery assembly from the first side face of the battery assembly if an absolute value of a difference between the actual depressing displacement amount and a preset standard depressing displacement amount is less than or equal to a preset depressing threshold; detect the first actual displacement amount and the first clamping force; and determine that the assembling is completed if an absolute value of a difference between the first actual displacement amount and a preset first standard displacement amount is less than or equal to a preset first displacement threshold, and an absolute value of a difference between the first clamping force and a preset first standard clamping force is less than or equal to a preset first clamping force threshold. In the present application, on the one hand, after determining that an absolute value of a difference between an actual pressing displacement amount and a preset standard pressing displacement amount is less than or equal to a preset pressing threshold, a clamping operation is then performed to ensure that a welding surface of a battery assembly is aligned with a reference plane so that a defocusing amount of the welding meets requirements and welding effect is ensured. On the other hand, in the clamping operation, by simultaneously determining an absolute value of a difference between a first actual displacement amount and a preset first standard displacement amount is less than or equal to a preset first displacement threshold, and an absolute value of a difference between a first clamping force and a preset first standard clamping force is less than or equal to a preset first clamping force threshold, it not only ensures that a displacement amount of a clamping device meets requirements, and at the same time, it also ensures that a clamping force applied to the battery assembly also meets requirements, thereby ensuring that there will be no errors in production sizes of the battery assembly, and welding seams that do not meet requirements, which can effectively avoid situations such as welding failure and scrapping of the battery assembly.

According to yet another aspect of an embodiment of the present application, provided is a welding device, including the battery assembly clamp in any of the above manners.

The welding device is applied in the production line of a battery. When the battery assembly is clamped in the battery assembly clamp, the pressing device moves upward, so that structures between the pressing device and the clamping device no longer interfere with each other, and then the clamping device is transferred to a welding station of the welding device for welding.

The above description is only an overview of the technical solutions of the present application. In order to understand the technical means of the present application more clearly, implementation can be made according to the contents of the specification, and in order to make the above and other purposes, features and advantages of the present application more obvious and understandable, the following specifically lists the specific embodiments of the present application.

Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for the purpose of illustrating the preferred embodiments and are not construed as limiting the present application. Moreover, in the whole drawings, like reference numerals are used to denote like components. In the drawings:.

Reference numerals in the specific embodiments are as follows:.

Embodiments of the technical solutions of the present application will be described in detail below in conjunction with the accompanying drawings. The following embodiments are only used to illustrate the technical solutions of the present application more clearly, and therefore are only examples, rather than limiting the protection scope of the present application.

It should be noted that, unless otherwise specified, technical terms or scientific terms used in the embodiments of the present application shall have common meanings understood by those skilled in the art to which the embodiments of the present application pertains.

In the description of the embodiments of the present application, orientations or positional relationships indicated by technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical" "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", or the like are based on orientations or positional relationships shown in the drawings, and are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that a device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limitations to the embodiments of the present application.

In addition, technical terms such as "first" and "second" are only used for descriptive purposes, and should not be understood as indicating or implying relative importance or implicitly specifying the number of the indicated technical features. In the description of the embodiments of the present application, "plurality" means two or more, unless otherwise specifically defined.

In the description of the embodiments of the present application, unless otherwise clearly specified and defined, technical terms such as "installation", "interconnection", "connection" and "fixation" should be interpreted in a broad sense, for example, it can be a fixed connection, or a detachable connection, or an integrated connection; it can also be a mechanical connection, or an electrical connection; it can be a direct connection, or an indirect connection through an intermediary, and it can be internal communication between two elements or interaction relationship between two elements. Those of ordinary skill in the art can understand the specific meanings of the above terms in the embodiments of the present application according to specific situations.

In the description of the embodiments of the present application, unless otherwise explicitly specified and defined, when a first feature is "above" or "below" a second feature, the first feature and the second feature may be in direct contact, or the first feature and the second feature may be in indirect contact through an intermediary. Moreover, when the first feature is "on", "above" and "over" the second feature, the first feature may be directly above or obliquely above the second feature, or the first feature may be simply higher than the second feature in the horizontal height. When the first feature is "under", "below" and "underneath" the second feature, the first feature may be directly below or obliquely below the second feature, or the first feature may be simply lower than the second feature in the horizontal height.

At present, judging from the development of market situation, application of power batteries is becoming more and more extensive. Power batteries are not only applied in energy storage power systems such as hydraulic, thermal, wind and solar power plants, but also widely applied in electric vehicles such as electric bicycles, electric motorcycles, and electric vehicles, as well as military equipment and aerospace and other fields. With the continuous expansion of application fields of the power batteries, their market demand is also constantly expanding.

In an automatic production line of a battery, an end cover and a housing of the battery are sealed and assembled by welding. Before welding, it is necessary to first rivet an end cover into a housing and guarantee that an end surface of the end cover is on the same plane as that of the housing, so as to ensure that a welding surface of the end cover is aligned with that of the housing. At the same time, in order to make a welding seam between the end cover and the housing meet requirements, it is necessary to clamp an edge of the housing by a clamp all around to reduce the gap between the end cover and the housing.

The welding between the end cover and the housing is generally carried out by laser welding, and a defocusing amount of laser welding has a great influence on welding quality. The defocusing amount is a distance between a laser focus and an acted substance. Laser welding usually requires a certain defocusing amount, because a power density at the center of a spot at the laser focus is too high, so that a hole is easy to be formed through evaporation, while power density distribution is relatively uniform on each plane away from the laser focus. Therefore, in the process of laser welding, high requirements are put forward for the accuracy of positioning of the end cover and the housing.

Before welding, the end cover is generally pressed to be aligned with a reference plate and riveted into an opening of the housing by the pressing device. When a screw bolt in the structure of the reference plate is loose, or there are abnormalities such as impurities on the surface of the reference plate, whether the end cover is aligned with the reference plate cannot be determined, which will lead to subsequent welding failure; and when the edge of the housing is clamped by the clamp, a too small clamping force easily causes a welding seam between the end cover and the housing to be too large, which will also lead to welding failure, while a too large clamping force also easily leads to deformation of the housing or the end cover.

In the current production line, a battery assembly realizes the alignment of top faces of an end cover and a housing with a welding reference plane through a restraint structure on a pressing device. Specifically, when a structural size is set, the pressing device is guaranteed to press downward to the maximum stroke, the top faces of the end cover and the housing are aligned with the welding reference plane. Similarly, by disposing the restraint structure on a clamping device, a side face of the housing can be clamped so that the size of a welding seam can meet welding requirements.

The inventors of the present application notice that, for the method of using the restraint structure to realize the alignment of the top faces of the end cover and the housing with the welding reference plane, when there are impurities between a contact face of the pressing device and the battery assembly or on a surface of the restraint structure, it will cause the maximum stroke of the pressing device to decrease, which results in insufficient positioning of the top faces of the end cover and the housing, and further failure of subsequent welding, scrapping of a battery, and the like. Similarly, when there are impurities between the clamping device and a side face of the battery assembly or on the surface of the restraint structure on the clamping device, a clamping force of the clamping device for the housing will be insufficient and the clamping force will be unevenly distributed, which results in the gap between the housing and the end cover is too large, and affects the effect of subsequent welding.

Based on this, the present application proposes a battery assembly assembling method, and the method is applied to a battery assembly clamp during a welding process, including determining whether pressing positioning of a battery assembly meets requirements by comparing an absolute value of a difference between an actual pressing displacement amount of a pressing device moving downward and a preset standard pressing displacement amount with a preset pressing threshold, and when the requirements are met, determining whether assembling is completed by comparing an absolute value of a difference between a first displacement amount of a clamping device and a preset first standard displacement amount with a first displacement threshold, and an absolute value of a difference between a first clamping force of the clamping device and a preset first standard clamping force with a first clamping force threshold. The present application obtains various assembling data synchronously when the battery assembly is assembled on the clamp, and compares the various assembling data with standard data, so as to ensure whether the positioning, clamping and other conditions of the battery assembly meet requirements during an assembling process. When the requirements are met, the battery assembly assembled on the clamp can be welded to ensure success rate of welding and avoid situations such as welding failure and scrapping of the battery assembly due to poor assembling of the battery assembly on the clamp.

Please refer to <FIG> is a schematic diagram of an exploded structure of a battery <NUM> provided by some embodiments of the present application. The battery <NUM> includes a box <NUM> and a battery cell <NUM>, and the battery cell <NUM> is accommodated in the box <NUM>. The box <NUM> is configured to provide accommodation space for the battery cell <NUM>, and the box <NUM> may adopt a variety of structures. In some embodiments, the box <NUM> may include a first part <NUM> and a second part <NUM>, the first part <NUM> and the second part <NUM> cover each other, and the first part <NUM> and the second part <NUM> jointly define the accommodation space for accommodating the battery cell <NUM>. The second part <NUM> may be a hollow structure with one end open, the first part <NUM> may be a plate-like structure, and the first part <NUM> covers an opening side of the second part <NUM>, so that the first part <NUM> and the second part <NUM> jointly define the accommodation space; or the first part <NUM> and the second part <NUM> may be hollow structures with one side open, and an opening side of the first part <NUM> covers the opening side of the second part <NUM>. Certainly, the box <NUM> formed by the first part <NUM> and the second part <NUM> may be in various shapes, such as a cylinder, a cuboid and the like.

In the battery <NUM>, a plurality of battery cells <NUM> may be provided. The plurality of battery cells <NUM> may be in series connection, parallel connection or series-parallel connection, and the series-parallel connection means that the plurality of battery cells <NUM> are connected in series and parallel. The plurality of battery cells <NUM> may be in direct series connection, parallel connection or series-parallel connection, and then the whole composed of the plurality of battery cells <NUM> is accommodated in the box <NUM>. Certainly, for the battery <NUM>, the plurality of battery cells <NUM> may be firstly connected in series, in parallel or in series-parallel to form a battery module, and then a plurality of battery modules are connected in series or in parallel or in series-parallel to form a whole, and then accommodated in the box <NUM>. The battery <NUM> may also include another structure, for example, the battery <NUM> may also include a bus component configured to implement electrical connection between the plurality of battery cells <NUM>.

Each battery cell <NUM> may be but not limited to a secondary battery or a primary battery, or may also be a lithium-sulfur battery, a sodium-ion battery or a magnesium-ion battery. The battery cell <NUM> may be cylindrical, flat, cuboid or in another shape.

Please refer to <FIG> is a schematic diagram of an exploded structure of a battery cell <NUM> in a battery <NUM> provided by some embodiments of the present application. The battery cell <NUM> refers to the smallest unit for constituting the battery. As shown in <FIG>, the battery cell <NUM> includes an end cover <NUM>, a housing <NUM>, a battery cell assembly <NUM> and other functional components.

The end cover <NUM> refers to a component that covers an opening of the housing <NUM> to isolate internal environment of the battery cell <NUM> from external environment. Without limitation, the end cover <NUM> may be adapted to the housing <NUM> in shape to fit the housing <NUM>. Optionally, the end cover <NUM> may be made of a material with a certain hardness and strength (such as aluminum alloy), and in this way, the end cover <NUM> does not easily deform when it is squeezed and collided, so that the battery cell <NUM> can have a higher structural strength and safety performance can also be improved. A functional component such as an electrode terminal 21a may be disposed on the end cover <NUM>. The electrode terminal 21a may be configured to be electrically connected with the battery cell assembly <NUM> for outputting or inputting electric energy of the battery cell <NUM>. In some embodiments, a pressure relief mechanism may be further disposed on the end cover <NUM>, and the pressure relief mechanism is configured to relieve an internal pressure when the internal pressure or temperature of the battery cell <NUM> reaches a threshold. The end cover <NUM> may also be made of various materials, for example, copper, iron, aluminum, stainless steel, aluminum alloy, plastic, or the like, which is not particularly limited in the embodiment of the present application. In some embodiments, an insulating member may be further disposed on an inner side of the end cover <NUM>, and the insulating member may be configured to isolate an electrical connection component in the housing <NUM> from the end cover <NUM> to reduce the risk of short circuit. Exemplarily, the insulating member may be plastic, rubber or the like.

The housing <NUM> is a component configured to cooperate with the end cover <NUM> to form the internal environment of the battery cell <NUM>, where the formed internal environment may be used to accommodate the battery cell assembly <NUM>, an electrolytic solution and other components. The housing <NUM> and the end cover <NUM> may be independent components, an opening may be provided on the housing <NUM>, and the end cover <NUM> covers the opening at the opening to form the internal environment of the battery cell <NUM>. Without limitation, the end cover <NUM> and the housing <NUM> may also be integrated. Specifically, the end cover <NUM> and the housing <NUM> may form a common connecting face first before other components are placed into the housing. When the interior of the housing <NUM> needs to be packaged, the end cover <NUM> then covers the housing <NUM>. The housing <NUM> may be in various shapes and sizes, such as a cuboid, a cylinder, and a hexagonal prism. Specifically, the shape of the housing <NUM> may be determined according to the specific shape and size of the battery cell assembly <NUM>. The housing <NUM> may be made of various materials, for example, copper, iron, aluminum, stainless steel, aluminum alloy, and plastic, which is not particularly limited in the embodiments of the present application.

The battery cell assembly <NUM> is a component in the battery cell <NUM> where an electrochemical reaction occurs. The housing <NUM> may contain one or more battery cell assemblies <NUM>. The battery cell assembly <NUM> is mainly formed by winding or stacking a positive electrode sheet and a negative electrode sheet, and a separator is usually disposed between the positive electrode sheet and the negative electrode sheet. Parts of the positive electrode sheet and the negative electrode sheet with active materials constitute a main body part of the battery cell assembly, and parts of the positive electrode sheet and the negative electrode sheet without active materials constitute tabs 23a respectively. A positive tab and a negative tab may be located at one end of the main body part together or at two ends of the main body part respectively. During the charging and discharging of the battery, a positive electrode active material and a negative electrode active material react with the electrolytic solution, and the tab 23a is connected to the electrode terminal 21a to form a current loop.

According to one aspect of embodiments of the present application, provided is a battery assembly assembling method, the method is applied to a battery assembly clamp, and the battery assembly clamp includes a pressing device and a clamping device. Please refer to <FIG> for details, <FIG> shows a flow of a battery assembly assembling method provided by an embodiment of the present application. The battery assembly assembling method includes:.

Specifically, the control unit first compares the actual pressing displacement amount with the preset standard pressing displacement amount to obtain the absolute value of the difference, and then compares the obtained absolute value of the difference with the preset pressing threshold to determine whether the actual pressing displacement amount meets requirements.

If the absolute value of the difference between the actual pressing displacement amount and the preset standard pressing displacement amount is less than or equal to the preset pressing threshold, it indicates that the actual pressing displacement amount meets the requirements, and then the flow proceeds to.

Specifically, a displacement sensor, a force sensor, a drive feedback device, or the like may be disposed on the clamping device so that the control unit can acquire the first actual displacement amount of the clamping device clamping the battery assembly from the first side face of the battery assembly and the first clamping force of the clamping device performing clamping from the first side face of the battery assembly.

Step S50: detecting the first actual displacement amount, and determining whether an absolute value of a difference between the first actual displacement amount and a preset first standard displacement amount is less than or equal to a preset first displacement threshold.

Specifically, the control unit compares the first actual displacement amount with the preset first standard displacement amount to obtain the absolute value of the difference, and then compares the obtained absolute value of the difference with the preset first displacement threshold to determine whether the first actual displacement amount meets requirements.

If the absolute value of the difference between the first actual displacement amount and the preset first standard displacement amount is less than or equal to the preset first displacement threshold, it indicates that the first actual displacement amount meets the requirements, and then the flow proceeds to
Step S60: detecting the first clamping force, and determining whether an absolute value of a difference between the first clamping force and a preset first standard clamping force is less than or equal to a preset first clamping force threshold.

Specifically, the control unit compares the first clamping force with the preset first standard clamping force to obtain the absolute value of the difference, and then compares the obtained absolute value of the difference with the preset first clamping force threshold to determine whether the first clamping force meets requirements.

If the absolute value of the difference between the first clamping force and the preset first standard clamping force is less than or equal to the preset first clamping force threshold, it indicates that the first clamping force meets the requirements, and assembling is completed.

Specifically, the pressing device is configured to press an end cover to be aligned with a reference plane and riveted into an opening of a housing, and the clamping device is configured to squeeze the housing to reduce the gap between an edge of the housing opening and the end cover. The first side face of the battery assembly is one side face of the housing used to enclose the opening. Similarly, a second side face of the battery assembly mentioned below is the other side face of the housing used to enclose the opening.

The inventors of the present application found in the research that when a displacement amount of a clamping device is small but a clamping force is appropriate, adaptability of a contact face between the clamping device and the battery assembly may be poor, and the clamping device may be only in partial contact with the battery assembly, so that the clamping force of the clamping device for the surface of the battery assembly is unevenly distributed, which results that a welding seam between an end cover and a housing only partially meets requirements; when the displacement amount of the clamping device is large but the clamping force is appropriate, the battery assembly may be squeezed and deformed; when the displacement amount of the clamping device is appropriate but the clamping force is small, errors may occur in the production process of the battery assembly, which results in that the size of the battery assembly is too small; and when the displacement amount of the clamping device is appropriate but the clamping force is large, on the one hand, the size of the battery assembly may be too large, and on the other hand, a surface of the battery housing may be uneven, so that the clamping device is in partial contact with the surface of the battery housing, and a force on the surface of the battery housing is uneven, which will also cause only part of the welding seam to meet requirements.

Based on the above problems, in the present application, on the one hand, after determining that an absolute value of a difference between an actual pressing displacement amount and a preset standard pressing displacement amount is less than or equal to a preset pressing threshold, a clamping operation is then performed to ensure that a welding surface of a battery assembly is aligned with a reference plane so that a defocusing amount of the welding meets requirements and welding effect is ensured. On the other hand, in the clamping operation, by simultaneously determining an absolute value of a difference between a first actual displacement amount and a preset first standard displacement amount is less than or equal to a preset first displacement threshold, and an absolute value of a difference between a first clamping force and a preset first standard clamping force is less than or equal to a preset first clamping force threshold, it not only ensures that a displacement amount of a clamping device meets requirements, and at the same time, it also ensures that a clamping force applied to the battery assembly also meets requirements, thereby ensuring that there will be no errors in production sizes of the battery assembly, and welding seams that do not meet requirements, which can effectively avoid situations such as welding failure and scrapping of the battery assembly.

Please refer to <FIG> shows another flow of a battery assembly assembling method provided by an embodiment of the present application. According to the present application, if the absolute value of the difference between the actual pressing displacement amount and the preset standard pressing displacement amount is greater than the preset pressing threshold, the flow proceeds to
Step S21: controlling the pressing device to move upward to be reset and press downward again.

Specifically, if the control unit detects that the absolute value of the difference between the actual pressing displacement amount and the preset standard pressing displacement amount is greater than the preset pressing threshold in step S20, it indicates that the actual pressing displacement amount does not meet requirements. In this case, the control unit controls the pressing device to move upward to be reset, then press downward again and drive the battery assembly to move downward, and then steps S10 and S20 are repeated. If the absolute value of the difference between the actual pressing displacement amount and the preset standard pressing displacement amount is subsequently detected to be less than or equal to the preset pressing threshold in step S20, step S30 is performed, and if the absolute value of the difference between the actual pressing displacement amount and the preset standard pressing displacement amount is subsequently detected to be still greater than the preset pressing threshold in step S20, the pressing device can be controlled again to move upward to be reset and press downward again, or manual intervention can be performed to check the cause.

Please continue to refer to <FIG>, according to some embodiments of the present application, if the absolute value of the difference between the first actual displacement amount and the preset first standard displacement amount is greater than the preset first displacement threshold, the clamping device is controlled to be reset and perform clamping again.

Specifically, if the control unit detects that the absolute value of the difference between the first actual displacement amount and the preset first standard displacement amount is greater than the preset first displacement threshold in step S50, it indicates that the first actual displacement amount does not meet requirements, and the flow proceeds to
Step S51: controlling the clamping device to be reset.

Then step S30 and step S40 are performed again.

Specifically, it is necessary to ensure that both the first actual displacement amount and the first clamping force meet requirements at the same time. Therefore, as long as the absolute value of the difference between the first actual displacement amount and the preset first standard displacement amount is detected to be greater than the preset first displacement threshold in step S50, it is not necessary to detect whether the first clamping force meets the requirements, and the control unit needs to control the clamping device to be reset and perform clamping again, and then steps S30, S40 and S50 are performed again. When the difference between the first actual displacement amount and the preset first standard displacement amount is subsequently detected to be greater than the preset first displacement threshold, steps S30, S40, and S50 can be repeated again, or manual intervention can be performed to check the cause. Similarly, the situation that the pressing displacement amount is not up to standard due to some accidental reasons of the clamping device or structure can be quickly eliminated, and the time cost of assembling can be reduced.

Please continue to refer to <FIG>, according to some embodiments of the present application, if the absolute value of the difference between the first clamping force and the preset first standard clamping force is greater than the preset first clamping force threshold, the clamping device is controlled to be reset and perform clamping again.

Specifically if the control unit detects that the absolute value of the difference between the first clamping force and the preset first standard clamping force is greater than the preset first clamping force threshold in step S60, it indicates that the first clamping force does not meet requirements, and the flow proceeds to
Step S51: controlling the clamping device to be reset.

Specifically, it is necessary to ensure that both the first actual displacement amount and the first clamping force meet requirements at the same time. Therefore, when the absolute value of the difference between the first clamping force and the preset first standard clamping force is detected to be greater than the preset first clamping force threshold in step S60, the control unit still needs to control the clamping device to be reset and perform clamping again even if the first actual displacement amount is detected to meet requirements, and then steps S30, S40 and S50 are performed again. When the absolute value of the difference between the first clamping force and the preset first standard clamping force is subsequently detected to be less than or equal to the first clamping force threshold, the assembling is completed. When the absolute value of the difference between the first clamping force and the preset first standard clamping force is subsequently detected to be greater than the first clamping force threshold, steps S30, S40, and S50 can be repeated again, or manual intervention can be performed to check the cause. Similarly, the situation that the pressing displacement amount is not up to standard due to some accidental reasons of the clamping device or structure can be quickly eliminated, and the time cost of assembling can be reduced.

Please continue to refer to <FIG>, according to some embodiments of the present application, the method further includes:
Step S70: controlling the clamping device to clamp the battery assembly from a second side face of the battery assembly that is adjacent to the first side face.

Specifically, when the battery assembly is a cuboid, the first side face and the second side face are two adjacent side faces. When the battery assembly is a cylinder, the first side face and the second side face may be a quarter of arc surface respectively. Similarly, when the battery assembly is in another shape, the first side face and the second side face are adjusted accordingly to ensure that the side face of the battery assembly can be completely clamped.

In addition, it should be noted that the control unit may control the clamping device to clamp the battery assembly from the first side face first, and then from the second side face, or control the clamping device to clamp the battery assembly from the first side face and the second side face at the same time.

Step S80: acquiring a second actual displacement amount of the clamping device and a second clamping force of the clamping device clamping the second side face of the battery assembly.

Step S90: detecting the second actual displacement amount, and determining whether an absolute value of a difference between the second actual displacement amount and a preset second standard displacement amount is less than or equal to a preset second displacement threshold.

If the absolute value of the difference between the second actual displacement amount and the preset second standard displacement amount is less than or equal to the preset second displacement threshold, then the flow proceeds to
Step <NUM>: detecting the second clamping force, and determining whether an absolute value of a difference between the second clamping force and a preset second standard clamping force is less than or equal to a preset second clamping force threshold.

When the absolute value of the difference between the second clamping force and the preset second standard clamping force is less than or equal to the second clamping force threshold, the assembling is completed.

By adding the step of controlling the clamping device to clamp the battery from the second side face of the battery assembly, and detecting the second actual displacement and the second clamping force of clamping the battery from the second side face of the battery assembly, it can ensure that the battery assembly is fully clamped all around, and further ensure that all points of a welding seam between an end cover and a housing of the battery assembly meet welding requirements, ensure success rate of welding, and improve welding effect.

It can be understood that, as shown in <FIG>, in some other embodiments of the present application, like the detection of the first actual displacement amount and the first clamping force described above, if at least one of the second actual displacement amount and the second clamping force is detected not to meet requirements in step S90 or S100, the flow proceeds to step S91: resetting the clamping device; and then the flow proceeds to steps S70, S80 and S90.

Certainly, if the battery assembly is irregular in shape, and the complete clamping of periphery edges cannot be achieved by clamping on both sides, the number of side faces to be clamped can also be increased adaptively according to the shape of the battery assembly to achieve the complete clamping of the side faces of the battery.

According to another aspect of an embodiment of the present application, provided is a battery assembly clamp. Please refer to <FIG> for details, <FIG> shows a structure of a battery assembly clamp provided by an embodiment of the present application. The battery assembly clamp <NUM> includes: a control unit <NUM>, and a pressing device <NUM>, a clamping device <NUM>, a first feedback unit <NUM> and a second feedback unit <NUM> respectively electrically connected to the control unit <NUM>. The pressing device <NUM> is configured to press and drive the battery to move downward. The first feedback unit <NUM> is disposed on the pressing device <NUM>, and is configured to detect an actual pressing displacement amount of the pressing device <NUM> moving downward and sending the actual pressing displacement amount to the control unit <NUM>. The clamping device <NUM> is configured to carry and clamp the battery assembly, and clamp the battery assembly from a first side face of the battery assembly. The second feedback unit <NUM> is disposed on the clamping device <NUM>, and is configured to detect a first actual displacement amount of the clamping device <NUM> and a first clamping force of the clamping device <NUM> performing clamping from the first side face of the battery assembly. The control unit <NUM> is configured to control the pressing device <NUM> to move downward, obtain the actual pressing displacement amount of the pressing device <NUM> moving downward, and control the clamping device <NUM> to clamp the battery assembly from the first side face of the battery assembly according to the actual pressing displacement amount. The control unit <NUM> is further configured to acquire the first actual displacement amount of the clamping device <NUM> and the first clamping force of the clamping device <NUM> performing clamping from the first side face of the battery assembly, and determine whether assembling is completed according to the first actual displacement amount and the first clamping force.

Please refer to <FIG> shows a cross-sectional structure of a battery assembly clamp provided by an embodiment of the present application. As shown in <FIG>, a top of the pressing device <NUM> is provided with a drive mechanism, such as a cylinder <NUM> shown in <FIG>, or an electric telescopic rod in other embodiments. A top of a cylinder barrel of the cylinder <NUM> is fixed, and a piston rod of the cylinder <NUM> is connected with the pressing device <NUM> to drive the pressing device <NUM> to move downward. A bottom of the pressing device <NUM> is provided with a pressing block <NUM>, and the pressing block <NUM> is configured to press the battery assembly <NUM> into the clamping device <NUM>, and align a top face of the battery assembly <NUM> with a reference plane when the clamping device <NUM> performs clamping.

The first feedback unit <NUM> may be a displacement sensor <NUM> as shown in <FIG>, which is configured to detect the pressing displacement amount of the pressing device <NUM> moving downward.

A first clamping plate <NUM> is disposed in the clamping device <NUM>, the first clamping plate <NUM> is configured to move and clamp the first side face of the battery assembly <NUM>, and a top face of the first clamping plate <NUM> is a reference plane for positioning the top of the battery assembly <NUM>. When the pressing block <NUM> presses the battery assembly <NUM>, it is necessary to ensure that the top face of the battery assembly <NUM> is aligned with the top face of the first clamping plate <NUM>.

The second feedback unit <NUM> may be an electric cylinder <NUM>. The electric cylinder <NUM> is a modular product that integrates a servo motor and a lead screw. A rotation motion of the servo motor is converted into a linear motion, and at the same time, advantages of the servo motor such as precise rotational speed control, precise revolution control, and precise torque control are transformed into precise speed control, precise position control, and precise thrust control, to achieve high-precision linear motion, and the electric cylinder <NUM> can feed back a displacement amount and a torque value to the control unit <NUM> in real time. The telescopic rod of the electric cylinder <NUM> is connected to the first clamping plate <NUM>, which on the one hand is configured to drive the first clamping plate <NUM> to move to clamp the battery assembly <NUM>, and on the other hand, feeds back a first actual displacement amount and a driving torque of the telescopic rod to the control unit <NUM>, and then feeds back the first actual displacement amount of the first clamping plate <NUM> and the first clamping force applied to the battery assembly <NUM>.

By disposing the first feedback unit <NUM> on the pressing device <NUM>, the first feedback unit <NUM> is configured to detect the actual pressing displacement amount of the pressing device <NUM> moving downward and send the actual pressing displacement amount to the control unit <NUM> so as to realize precise positioning of the battery assembly <NUM>. By disposing the second feedback unit <NUM> on the clamping device <NUM>, the second feedback unit <NUM> is configured to detect the first actual displacement amount and the first clamping force of the clamping device <NUM> and send the first actual displacement amount and the first clamping force to the control unit <NUM> so as to ensure the accuracy of the clamping position and clamping force of the clamping device <NUM> for the battery assembly <NUM>, and further ensure that conditions such as a defocusing amount and a welding seam during the subsequent welding of the battery assembly <NUM> meet requirements.

Please refer to <FIG> again, according to some embodiments of the present application, the first feedback unit <NUM> includes a displacement sensor <NUM>.

The displacement sensor, also known as linear sensor, is a linear device attributed to metal induction. The function of the sensor is to convert various measured physical quantities into electricity. In a production process, measurement of displacement is generally divided into two types: measurement of physical size and mechanical displacement. According to different transformation forms of the measured variable, the displacement sensor may be divided into two types: an analog type and a digital type. The analog type may also be divided into a physical type and a structural type. Commonly used displacement sensors are mostly of analog structural types, including potentiometer displacement sensors, inductive displacement sensors, auto-alignment machines, capacitive displacement sensors, eddy current displacement sensors, Hall displacement sensors, and the like. An important advantage of digital displacement sensors is the convenience of sending a signal directly into a computer system. This kind of sensor develops rapidly and is widely applied.

By setting the first feedback unit <NUM> as the displacement sensor <NUM>, it is possible to effectively ensure accurate measurement of the pressing displacement amount of the pressing device <NUM>, thereby ensuring that a defocusing amount between a welding plane and a welding head of the battery assembly <NUM> meet requirements, and ensuring success rate of welding.

Please refer to <FIG> shows an internal structure of a clamping device <NUM> in a battery assembly clamp provided by an embodiment of the present application. According to some embodiments of the present application, a carrying platform <NUM> for placing the battery assembly <NUM> is disposed in the clamping device <NUM>, a bottom of the carrying platform <NUM> is connected to the clamping device <NUM> through a first elastic member <NUM>, and the first elastic member <NUM> is configured to provide an upward elastic force for the carrying platform <NUM>.

The carrying platform <NUM> is disposed inside the clamping device <NUM> and is a plate or block structure with a plane for placing the battery assembly <NUM>.

The first elastic member <NUM> may be a spring, a shrapnel, or the like. The bottom of the carrying platform <NUM> is connected to the clamping device <NUM> through the first elastic member <NUM>. The first elastic member <NUM> is configured to provide the upward elastic force for the carrying platform <NUM>. When the battery assembly <NUM> is not pressed down, the first elastic member <NUM> lifts the carrying platform <NUM> to the top of the clamping device <NUM>, which on the one hand ensures the stability of the battery assembly <NUM> when it is placed on the carrying platform <NUM>, and on the other hand, ensures that when the battery assembly <NUM> is discharged, the battery assembly <NUM> can be sent out from the top of the clamping device <NUM> through the first elastic member <NUM>.

Please refer to <FIG> shows a top view structure inside a clamping device in a battery assembly clamp provided by an embodiment of the present application. According to some embodiments of the present application, a restraint plate <NUM> is disposed in the clamping device <NUM>, a movable first clamping plate <NUM> is disposed at a position opposite to the restraint plate <NUM> in the clamping device <NUM>, and the first clamping plate <NUM> is configured to clamp the battery assembly <NUM> from the first side face of the battery assembly <NUM> when the first clamping plate <NUM> moves, so that the battery assembly <NUM> is clamped between the first clamping plate <NUM> and the restraint plate <NUM>.

The restraint plate <NUM> is a plate structure fixed in the clamping device <NUM>. For the assembling of the cuboid battery assembly <NUM> as shown in <FIG>, the first clamping plate <NUM> is disposed in parallel with the restraint plate <NUM>. The first clamping plate <NUM> may be slidably disposed in the clamping device <NUM> through a slide rail structure, and a sliding direction of the first clamping plate <NUM> is an x-axis direction in <FIG>.

By disposing the restraint plate <NUM> in the clamping device <NUM>, the movable first clamping plate <NUM> is disposed at a position opposite to the restraint plate <NUM>, so that the battery assembly <NUM> can be firmly clamped between the first clamping plate <NUM> and the restraint plate <NUM> when the first clamping plate <NUM> moves.

Please continue to refer to <FIG>, according to some embodiments of the present application, the second feedback unit <NUM> includes an electric cylinder <NUM>, and the electric cylinder <NUM> is connected to the first clamping plate <NUM> for driving the first clamping plate <NUM> to move.

Specifically, as shown in <FIG>, the electric cylinder <NUM> includes a cylinder barrel <NUM> and a telescopic rod <NUM>, the cylinder barrel is fixed on the clamping device <NUM>, and an end of the telescopic rod <NUM> is connected to the first clamping plate <NUM>. By controlling the sliding of the telescopic rod <NUM>, driving of the first clamping plate <NUM> is realized.

By setting the second feedback unit <NUM> as the electric cylinder <NUM>, and the electric cylinder <NUM> to be connected to the first clamping plate <NUM>, not only the driving of the first clamping plate <NUM> is realized, but also detection and feedback of the first actual displacement amount of the first clamping plate <NUM> and the first clamping force of the first clamping plate <NUM> for the battery assembly <NUM> can be realized.

Please continue to refer to <FIG>, according to some embodiments of the present application, the first clamping plate <NUM> is connected to the electric cylinder <NUM> through a second elastic member <NUM>, so that the first clamping plate <NUM> is able to be tilt against the first side face of the battery assembly <NUM>.

As shown in <FIG>, a plurality of second elastic members <NUM> may be disposed between the first clamping plate <NUM> and the electric cylinder <NUM>, and the second elastic member <NUM> may be a spring, a shrapnel, or the like. The first clamping plate <NUM> is connected to the electric cylinder <NUM> through the second elastic members <NUM> so that the first clamping plate <NUM> is able to be tilted to a certain extent. If the first side face of the battery assembly <NUM> is tilted to a certain extent due to production reasons, the first clamping plate <NUM> moves and contacts the first side face of the battery assembly <NUM> so as to clamp the battery assembly <NUM>, and the first clamping plate <NUM> is able to be tilted correspondingly with the tilting of the first side face, so that the first clamping plate <NUM> exerts the more uniform clamping force on the first side face of the battery assembly <NUM>, and exhibits an ability of self-adaptive adjustment for clamping the battery assembly <NUM> to ensure the reliability of clamping.

Please refer to <FIG> again, according to some embodiments of the present application, a movable second clamping plate <NUM> is further disposed in the clamping device <NUM>, and the second clamping plate <NUM> is configured to clamp the battery assembly <NUM> from a second side face of the battery assembly <NUM> that is adjacent to the first side face when the second clamping plate <NUM> moves.

Similarly, a fixing plate <NUM> may further be fixed in the clamping device <NUM>, and the second clamping plate <NUM> is disposed opposite to the fixing plate <NUM>. For a cuboid battery as shown in <FIG>, the second clamping plate <NUM> and the fixing plate <NUM> are parallel to each other, and the second clamping plate <NUM> can move in a y-axis direction in <FIG>, and clamp the battery assembly <NUM> from the second side face of the battery assembly <NUM>.

By disposing the movable second clamping plate <NUM> in the clamping device <NUM>, the second clamping plate <NUM> is configured to clamp the battery assembly <NUM> from a second side face of the battery assembly <NUM> that is adjacent to the first side face when the second clamping plate <NUM> moves, so as to clamp the battery assembly <NUM> completely and fully, thereby ensuring that a welding seam on a welding plane of the battery assembly meets requirements and ensuring success rate of welding.

Please continue to refer to <FIG>, according to some embodiments of the present application, both the restraint plate <NUM> and the first clamping plate <NUM> are able to move in a moving direction of the second clamping plate <NUM>.

Specifically, as shown in <FIG>, a first slide rail <NUM> may be disposed on the end of the telescopic rod <NUM> of the electric cylinder <NUM> along the y-axis direction, the first clamping plate <NUM> may be slidably disposed on the first slide rail <NUM>, and the restraint plate <NUM> may be fixed on the clamping device <NUM> through a second slide rail <NUM> disposed along the y-axis direction. After the first clamping plate <NUM> clamps the battery assembly <NUM>, when the second clamping plate <NUM> moves along the y-axis direction and clamps the battery assembly <NUM>, the first clamping plate <NUM> and the restraint plate <NUM> can move with the battery assembly <NUM> to ensure that both the first clamping plate <NUM> and the restraint plate <NUM> remain relatively stationary with the battery assembly <NUM>.

By setting the restraint plate <NUM> and the first clamping plate <NUM> to be able to move in the moving direction of the second clamping plate <NUM>, it ensures that when the second clamping plate <NUM> moves along the y-axis direction and clamps the battery assembly <NUM>, the first clamping plate <NUM> and the restraint plate <NUM> can move with the battery assembly <NUM> to prevent friction between the battery assembly <NUM> and the first clamping plate <NUM> and the restraint plate <NUM>, so as not to cause abrasion or even damage to the surface of the battery assembly <NUM>.

According to yet another aspect of an embodiment of the present application, a welding device is further provided, and the welding device includes the battery assembly clamp <NUM> in any one of the above embodiments.

The welding device is applied in the production line of a battery. When the battery assembly <NUM> is clamped by the battery assembly clamp <NUM>, the pressing device <NUM> moves upward, so that structures between the pressing device <NUM> and the clamping device <NUM> no longer interfere with each other, and then the clamping device <NUM> is transferred to a welding station of the welding device for welding.

By disposing the first feedback unit <NUM> on the pressing device <NUM>, the first feedback unit <NUM> is configured to detect the actual pressing displacement amount of the pressing device <NUM> moving downward and send the actual pressing displacement amount to the control unit <NUM> so as to realize precise positioning of the battery assembly <NUM>. By disposing the second feedback unit <NUM> on the clamping device <NUM>, the second feedback unit <NUM> is configured to detect the first actual displacement amount and the first clamping force of the clamping device <NUM> and send the first actual displacement amount and the first clamping force to the control unit <NUM> so as to ensure the accuracy of the clamping position and clamping force of the clamping device <NUM> for the battery assembly <NUM>, and further ensure that conditions such as a defocusing amount and a welding seam during welding of the battery assembly <NUM> by the welding device meet requirements.

Claim 1:
A battery assembly assembling method, applied to a battery assembly clamp (<NUM>) comprising a control unit (<NUM>), a pressing device (<NUM>), a clamping device (<NUM>) a first feedback unit (<NUM>) and a second feedback unit (<NUM>) respectively electrically connected to the control unit (<NUM>),
the method comprising:
acquiring an actual pressing displacement amount of the pressing device (<NUM>) moving downward;
detecting the actual pressing displacement amount using the first feedback unit (<NUM>); characterized in that
controlling the clamping device (<NUM>) using the control unit (<NUM>) to clamp the battery assembly (<NUM>) from a first side face of the battery assembly (<NUM>) if an absolute value of a difference between the actual pressing displacement amount and a preset standard pressing displacement amount is less than or equal to a preset pressing threshold; and controlling the pressing device (<NUM>) using the control unit (<NUM>) to move upward to be reset and press downward again if the absolute value of the difference between the actual pressing displacement amount and the preset standard pressing displacement amount is greater than the preset pressing threshold,
acquiring a first actual displacement amount of the clamping device (<NUM>) and a first clamping force of the clamping device (<NUM>) performing clamping from the first side face of the battery assembly (<NUM>);
detecting the first actual displacement amount and the first clamping force using the second feedback unit (<NUM>); and
determining that assembling is completed using the control unit (<NUM>) if an absolute value of a difference between the first actual displacement amount and a preset first standard displacement amount is less than or equal to a preset first displacement threshold, and an absolute value of a difference between the first clamping force and a preset first standard clamping force is less than or equal to a preset first clamping force threshold.