Patent Publication Number: US-2022223930-A1

Title: Sampling component, battery module, battery pack, and device

Description:
This application claims priority to Chinese Patent Application No. 201922495201.4, filed with the Chinese Patent Office on Dec. 31, 2019 and entitled “SAMPLING COMPONENT, BATTERY MODULE, BATTERY PACK, AND DEVICE,” which is incorporated herein by reference in its entirety. 
     TECHNICAL FIELD 
     This application relates to the technical field of energy storage devices, and in particular, to a sampling component, a battery module, a battery pack, and a device. 
     BACKGROUND 
     The battery module includes battery cells. Electrode leads of adjacent battery cells are connected by a connecting plate. The battery cells generate heat during operation. Accumulation of heat increases a temperature of the battery module. To keep high efficiency of the battery module, the temperature of the battery module needs to be controlled to be within a normal operating temperature range as far as possible. The battery module obtains the temperature of the battery cells during operation by collecting voltage of the connecting plate by means of an FPC (flexible printed circuit, FPC for short). In the related art, the FPC is connected to the connecting plate by welding. However, due to a relatively high temperature during the welding, a risk of damaging an electronic device in the FPC exists, thereby affecting measurement precision and reliability of the FPC. 
     SUMMARY 
     This application provides a sampling component, a battery module, a battery pack, and a device. The sampling component achieves a relatively high precision and reliability of collection performed on a battery cell. 
     A first aspect of embodiments of this application provides a sampling pack. The sampling pack includes: 
     a circuit board, where the circuit board includes a signal collecting portion and an insulation film connected to the signal collecting portion; and 
     a connecting part, where the connecting part includes a body portion and a connecting portion, the body portion is connected to the connecting portion, and the connecting portion is electrically connected to the signal collecting portion, 
     where, in a height direction, the connecting portion includes a first connecting section and a second connecting section, and the first connecting section is connected to the second connecting section; and 
     in the height direction, at least a part of the signal collecting portion is located between the first connecting section and the second connecting section. 
     In some embodiments, a second through-hole is opened on the signal collecting part. The first connecting section passes through the second through-hole, so that at least a part of the signal collecting part is located between the first connecting section and the second connecting section. 
     In some embodiments, a first through-hole is opened on the insulation film. At least a part of the connecting portion passes through the first through-hole and is connected to the signal collecting portion. 
     In some embodiments, the first connecting section includes a plurality of tips. In a direction toward the circuit board, a cross-sectional area of each tip gradually decreases. 
     The tip is able to pierce the insulation film, and is bendable against the second connecting section, so that at least a part of the signal collecting portion is located between the first connecting section and the second connecting section. 
     In some embodiments, the connecting part further includes a buffer portion. The buffer portion is connected to the connecting portion and the body portion. 
     The buffer portion includes a plurality of bend structures, and each bend structure protrudes in the height direction. 
     In some embodiments, a gap exists between adjacent bend structures. 
     In some embodiments, the connecting part further includes a transition portion. The body portion is connected to the buffer portion. The transition portion is connected between the buffer portion and the connecting portion. 
     In some embodiments, a reinforcing structure is disposed on the transition portion, and the reinforcing structure is arc-shaped. 
     In some embodiments, a material of the connecting part includes a copper-nickel alloy. 
     A second aspect of embodiments of this application provides a battery module. The battery module includes: 
     a battery cell, where the battery cell includes an electrode lead; 
     a connecting plate, where the connecting plate is connected to the electrode lead of the battery cell; and 
     a sampling component, where the sampling component is the sampling component described above, where, the sampling component is connected to the connecting plate by a connecting part. 
     In some embodiments, a limiting structure is disposed on the body portion. 
     A limiting hole is opened on the connecting plate, and the limiting structure fits with the limiting hole. 
     A third aspect of embodiments of this application provides a battery pack. The battery pack includes: 
     a box body, where the box body includes an accommodation cavity; and 
     a battery module, where the battery module is the battery module described above, where, the battery module is accommodated in the accommodation cavity. 
     A fourth aspect of embodiments of this application provides a device. The device uses a battery cell as a power supply. The device includes: 
     a power source, where the power source is configured to provide a driving force to the device; and 
     the battery module described above, which is configured to provide electrical energy to the power source, or the battery pack described above, which is configured to provide electrical energy to the power source. 
     In the embodiments of this application, the circuit board of the sampling component is electrically connected to the connecting plate by the connecting part, and mechanically connected by the connecting part. That is, the circuit board does not need to be directly welded to the connecting plate, thereby reducing risks of damage to an electronic device in the circuit board caused by a too high welding temperature, and improving precision and reliability of collection performed by the circuit board on an electrode lead of the battery cell. In addition, without the need of welding between the circuit board and the connecting plate, requirements of high-temperature resistance performance on the insulation film are lowered. That is, the insulation film may be made of a material with relatively low performance of high-temperature resistance, thereby reducing the cost of the insulation film. 
     Understandably, the above general description and the following detailed description are merely exemplary without limiting this application. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       To describe the technical solutions in the embodiments of this application or the prior art more clearly, the following outlines the drawings to be used in the description of the embodiments of this application or the prior art. Apparently, the drawings outlined below are merely some embodiments of this application, and a person of ordinary skill in the art may derive other drawings from the outlined drawings without making any creative efforts. 
         FIG. 1  is a schematic structural diagram of a device according to a specific embodiment of this application; 
         FIG. 2  is an exploded view of a battery pack shown in  FIG. 1  according to a specific embodiment; 
         FIG. 3  is a schematic structural diagram of a battery module shown in  FIG. 2  according to a specific embodiment; 
         FIG. 4  is an exploded view of  FIG. 3 ; 
         FIG. 5  is a local detailed view of part I shown in  FIG. 3 , where the first connecting section is in an initial state; 
         FIG. 6  is a local detailed view of part I shown in  FIG. 3 , where the first connecting section is in a connected state; 
         FIG. 7  is a local exploded view of a sampling component shown in  FIG. 4 ; 
         FIG. 8  is a local detailed view of part II shown in  FIG. 7 , where a signal collecting portion is based on a first embodiment; 
         FIG. 9  is a local detailed view of part II shown in  FIG. 7 , where a signal collecting portion is based on a second embodiment; 
         FIG. 10  is a schematic structural diagram of a connecting part provided in this application according to a first specific embodiment; 
         FIG. 11  is a schematic structural diagram of a connecting part provided in this application according to a second specific embodiment, where the first connecting section is in an initial state; and 
         FIG. 12  is a schematic structural diagram of a connecting part provided in this application according to a third specific embodiment, where the first connecting section is in a connected state. 
     
    
    
     REFERENCE NUMERALS 
     
         
         
           
             D—Device; 
             M—Battery pack; 
             M 1 —Box body;
           M 11 —Upper box;   M 12 —Lower box;   M 13 —Accommodation cavity;   M 2 —Battery module;   
         
               1 —Sampling component;
             11 —Circuit board;
                 111 —Insulation film;
                     111   a —First insulation film;     111   b —Second insulation film;     111   c —First through-hole;   
                     112 —Signal collecting portion;
                     112   a —Sampling wire;     112   b —Conductive plate;     112   c —Second through-hole;   
                   
                 12 —Connecting part;
                 121 —Body portion;
                     121   a —Limiting structure;   
                     122 : Connecting portion;
                     122   a —First connecting section;     122   b —Second connecting section;     122   c —Guide trough;     122   d —Accommodation cavity;     122   e —Tip;         123 —Buffer portion;
                     123   a —Bend structure;     123   b —Gap;   
                     124 —Transition portion;
                     124   a —Reinforcing structure;   
                   
               
         
               2 —Connecting plate;
             21 —Limiting hole;   
         
               3 —End plate; 
               4 —Side plate; 
               5 —Battery cell; and
             51 —Electrode lead.   
         
           
         
       
    
     The drawings described here are incorporated into the specification as a part of the specification. The drawings illustrate embodiments of this application and are used together with the specification to interpret the principles of this application. 
     DETAILED DESCRIPTION OF EMBODIMENTS 
     For better understanding of the technical solutions of this application, the following describes embodiments of this application in detail with reference to accompanying drawings. 
     Apparently, the embodiments described herein are merely a part of the embodiments of this application rather than an entirety of the embodiments. All other embodiments derived by a person of ordinary skill in the art based on the embodiments of this application without making any creative efforts shall fall within the protection scope of this application. 
     The terms used in the embodiments of this application are intended only for describing specific embodiments rather than for limiting this application. Unless otherwise expressly indicated in the context, the words “a”, “the”, and “this” that precede a singular noun in the embodiments and claims of this application are intended to include the plural form thereof. 
     Understandably, the term “and/or” used herein merely describes an association relationship between associated objects and indicates existence of three relationships. For example, “A and/or B” may indicate existence of A alone, coexistence of A and B, and existence of B alone. In addition, the character “/” herein generally indicates an “or” relationship between the object preceding the character and the object following the character. 
     It needs to be noted that directional terms such as “on”, “above”, “under”, “below”, “left”, and “right” used in the embodiments of this application are described from a perspective shown in the accompanying drawings, and shall not be understood as a limitation on the embodiments of this application. In addition, understandably, depending on the context, one element described as being connected “on” or “under” another element not only means that the element may be directly connected “on” or “under” the other element, but also means that the element may be indirectly connected “on” or “under” the other element through an intermediate element. 
     An embodiment of this application provides a device D that uses a battery cell  5  as a power supply, a battery pack M, and a battery module M 2 . The device D that uses a battery cell  5  as a power supply may be a mobile device such as a vehicle, a ship, or a small aircraft. The device D contains a power source, and the power source is configured to provide a driving force for the device D. The power source may be configured as a battery module M 2  (or a battery pack M) that provides electrical energy to the device D. The driving force of the device D may be sole electrical energy, or may include electrical energy and other types of energy (such as mechanical energy). The power source may be a battery module M 2  (or a battery pack M), or may be a combination of a battery module M 2  (or a battery pack M) and an engine, or the like. Therefore, all devices D that can use a battery cell  5  as a power supply fall within the protection scope of this application. 
     As shown in  FIG. 1 , using a vehicle as an example, an apparatus D in an embodiment of this application may be a new energy vehicle. The new energy vehicle may be a battery electric vehicle, or may be a hybrid electric vehicle or a range-extended electric vehicle or the like. The vehicle may include a battery pack M and a vehicle body. The battery pack M is disposed in the vehicle body. A driving motor is further disposed in the vehicle body, and the driving motor is electrically connected to the battery pack M. The battery pack M provides electrical energy. The driving motor is connected to wheels of the vehicle body through a transmission mechanism to drive the vehicle to run. Specifically, the battery pack M may be horizontally disposed at a bottom of the vehicle body. 
     As shown in  FIG. 2 , the battery pack M includes a box body M 1  and a battery module M 2  that is disclosed in this application. The box body M 1  has an accommodation cavity M 13 . The battery module M 2  is accommodated in the accommodation cavity M 13 . The battery module M 2  may be one or more in number. A plurality of battery modules M 2  are arranged in the accommodation cavity M 13 . The box body M 1  is not limited in terms of type, and may be a frame shape, a disk shape, or a box shape. Specifically, as shown in  FIG. 2 , the box body M 1  may include a lower box M 12  accommodating the battery module M 2  and an upper box M 11  snap-fitted with the lower box M 12 . 
     More specifically, as shown in  FIG. 3 , the battery module M 2  includes a plurality of battery cells  5  and a frame structure configured to fix the battery cells  5 . The plurality of battery cells  5  are stacked along a length direction X. The frame structure includes end plates  3 . The end plates  3  are respectively located at two ends of the stacked battery cells  5  along the length direction X, and are configured to limit movement of the battery cells  5  along the length direction X. In addition, in a specific embodiment, the frame structure may further include side plates  4 . The two side plates  4  are respectively located on two sides of the stacked battery cells  5  along a width direction Y, and the side plates  4  are connected to the end plates  3  to form the frame structure. 
     Specifically, the battery cells  5  include electrode leads  51 . Each battery cell  5  includes a positive electrode lead and a negative electrode lead. In the battery module, the plurality of battery cells  5  are electrically connected to each other, and specifically, may be connected in series, in parallel or in both series and parallel or the like. The electrode leads  51  of different battery cells are connected by a connecting plate  2 . For example, when the battery cells  5  are connected in series, a positive electrode lead of a battery cell  5  is connected to a negative electrode lead of an adjacent battery cell  5  by the connecting plate  2 . 
     In addition, as shown in  FIG. 3  and  FIG. 4 , the battery module M 2  further includes a sampling component  1 . The sampling component  1  is configured to collect signals such as temperature and voltage during operation of the battery cell  5 . The collected signals are output through a connector. The sampling component  1  is electrically connected to the connecting plate  2  so that information about the battery cell  5  can be collected through the connecting plate  2 . 
     Specifically, as shown in  FIG. 5 , the sampling component  1  includes a circuit board  11  and a connecting part  12 . The circuit board  11  includes a signal collecting portion  112  and an insulation film  111  connected to the signal collecting portion  112 . The signal collecting portion  112  is configured to collect the information about the battery cell  5 . The insulation film  111  provides insulation protection for the signal collecting portion  112 . As shown in  FIG. 5  and  FIG. 6 , the connecting part  12  connects the circuit board  11  and the connecting plate  2 . In this way, the electrode lead  51  of the battery cell  5  is connected to the circuit board  11  by the connecting part  12  and the connecting plate  2  to implement the collection of the information about the battery cell  5 . 
     As shown in  FIG. 5 ,  FIG. 6 , and  FIG. 10 , the connecting part  12  includes a body portion  121  and a connecting portion  122 . The body portion  121  is connected to the connecting portion  122 . The connecting part  12  is electrically connected to the signal collecting portion  112 . In a height direction Z, the connecting portion  122  includes a first connecting section  122   a  and a second connecting section  122   b . The first connecting section  122   a  is connected to the second connecting section  122   b . In the height direction Z, at least a part of the signal collecting portion  112  is located between the first connecting section  122   a  and the second connecting section  122   b.    
     In this embodiment of this application, the circuit board  11  of the sampling component  1  is electrically connected to the connecting plate  2  by the connecting part  12 , and mechanically connected by the connecting part  12 . That is, the circuit board  11  does not need to be directly welded to the connecting plate  2 , thereby reducing risks of damage to an electronic device in the circuit board  11  caused by a too high welding temperature, and improving precision and reliability of collection performed by the circuit board  11  on the electrode lead  51  of the battery cell  5 . In addition, without the need of welding between the circuit board  11  and the connecting plate  2 , requirements of high-temperature resistance performance on the insulation film  111  are lowered. That is, the insulation film  111  may be made of a material with relatively low performance of high-temperature resistance, thereby reducing the cost of the insulation film  111 . 
     When the circuit board  11  is connected to the connecting part  12 , in the height direction Z, at least a part of the signal collecting portion  112  is located between the first connecting section  122   a  and the second connecting section  122   b  of the connecting portion  122 , so as to connect to the signal collecting portion  112  through the first connecting section  122   a  and the second connecting section  122   b , and to electrically connect to the signal collecting portion  112 . 
     Specifically, as shown in  FIG. 9  to  FIG. 11 , a second through-hole  112   c  is opened on the signal collecting portion  112 . The first connecting section  122   a  of the connecting portion  122  can penetrate the second through-hole  112   c , so that at least a part of the signal collecting portion  112  is located between the first connecting section  122   a  and the second connecting section  122   b . In this embodiment, after the first connecting section  122   a  passes through the second through-hole  112   c , it is convenient to implement the connection between the connecting portion  122  and the signal collecting portion  112 . 
     In this embodiment, the second through-hole  112   c  is disposed on the signal collecting portion  112  to facilitate connection between the connecting portion  122  and the signal collecting portion  112 , increase integrity of the signal collecting portion  112 , and reduce risks of deformation and fracture of the signal collecting portion  112 . 
     In some embodiments, as shown in  FIG. 9 , a first through-hole  111   c  is opened on the insulation film  111 . In the thickness direction Z of the sampling component  1 , at least a part of the connecting portion  122  passes through the first through-hole  111   c  and is connected to the signal collecting portion  112 . 
     In this embodiment, as shown in  FIG. 9 , the connecting part  12  and the insulation film  111  are arranged along the thickness direction Z. Through the first through-hole  111   c  opened on the insulation film  111 , the connecting portion  122  of the connecting part  12  can pass through the first through-hole  111   c  along the thickness direction Z, and extends into the sampling component  1  to get electrically connected to the signal collecting portion  112 . That is, the first through-hole  111   c  disposed facilitates signal collection. 
     In the embodiment shown in  FIG. 11 , after passing through the second through-hole  112   c , the first connecting section  122   a  extending in the thickness direction Z can bend against the signal collecting portion  112 . After the bending, along the thickness direction Z, the first connecting section  122   a  abuts against the signal collecting portion  112 , and/or, the second connecting section  122   b  abuts against the signal collecting portion  112 . More specifically, as shown in  FIG. 9 , two second through-holes  112   c  may be opened on the signal collecting portion  112 , and the two second through-holes  112   c  are spaced out. The connecting portion  122  may include two first connecting sections  122   a  that are spaced out. The two first connecting sections  122   a  can pass through the two second through-holes  112   c  respectively, and bend against the signal collecting portion  112 . The two first connecting sections  122   a  are bent toward each other. The two first connecting sections  122   a  and the second connecting section  122   b  form an encircling structure shown in  FIG. 11 , and define an accommodation cavity  122   d . The signal collecting portion  112  between the two second through-holes  112   c  is located in the accommodation cavity  122   d . In this embodiment, a connection area between the connecting part  12  and the signal collecting portion  112  of this structure is relatively large, thereby improving reliability of the connection between the connecting part and the signal collecting portion and improving stability of signal collection. 
     In another embodiment, as shown in  FIG. 8 , the signal collecting portion  112  may contain no second through-hole. The signal collecting portion  112  may include a conductive plate  112   b  and a sampling wire  112   a . The sampling wire  112   a  is configured to collect a signal of the battery cell  5 . The conductive plate  112   b  is electrically connected to the sampling wire  112   a . The sampling wire  112   a  is located on a side of the conductive plate  112   b , the side being close to the connecting part  12 . Therefore, at least a part of the sampling wire  112   a  can be located in the accommodation cavity  122   d , thereby implementing connection between the connecting part  12  and the sampling wire  112   a.    
     In this embodiment, the sampling wire  112   a  disposed in the signal collecting portion  112  facilitates connection between the signal collecting portion  112  and the connecting part  12 , and improves reliability of the connection. 
     In another embodiment, as shown in  FIG. 12 , in the connecting portion  122  of the connecting part  12 , the first connecting section  122   a  includes a plurality of tips  122   e . A cross-sectional area of each tip  122   e  gradually decreases in a direction toward the circuit board  11 . When the connecting part  12  is connected to the circuit board  11 , as shown in  FIG. 5 , the tip  122   e  can pierce the insulation film  111  of the circuit board  11 , and can bend against the second connecting section  122   b , as shown in  FIG. 6 . In this way, at least a part of the signal collecting portion  112  is located between the first connecting section  122   a  and the second connecting section  122   b.    
     In this embodiment, the first through-hole does not need to be disposed on the insulation film  111  of the circuit board  11  beforehand, but the tip  122   e  of the connecting part  12  just pierces the insulation film  111  when the connecting part  12  is connected to the circuit board  11 . Therefore, the connection position between the connecting part  12  and the circuit board  11  is not limited by the position of the first through-hole, thereby improving flexibility of connection between the connecting part  12  and the circuit board  11 . 
     In this embodiment, a second through-hole  112   c  may be disposed in the signal collecting portion  112 . After piercing the insulation film  111 , the tip  122   e  can pass through the second through-hole  112   c  to get connected to the signal collecting portion  112 . Alternatively, as shown in  FIG. 8 , the signal collecting portion  112  may contain no second through-hole. In this case, the signal collecting portion  112  may include a conductive plate  112   b  and a sampling wire  112   a . The sampling wire  112   a  is configured to collect a signal of the battery cell  5 . The conductive plate  112   b  is electrically connected to the sampling wire  112   a . The sampling wire  112   a  is located on a side of the conductive plate  112   b , the side being close to the connecting part  12 . Therefore, after piercing the insulation film  111 , the tip  122   e  can be connected to the sampling wire  112   a . To be specific, at least a part of the sampling wire  112   a  can be located between the tip  122   e  and the second connecting section  112   b  so that the sampling wire  112   a  is connected to the tip  122   e.    
     In this embodiment, as shown in  FIG. 12 , a guide trough  122   c  is disposed on the second connecting section  122   b  of the connecting part  12 . The connecting portion  122  of the connecting part  12  may include a plurality of tips  122   e , and include two rows of tips  122   e  that are parallel to each other. Each row of tips  122   e  includes a plurality of tips  122   e  spaced out. The two rows of tips  122   e  can bend toward each other. After the bending, a preset space exists between the tips  122   e  and a bottom wall of the guide trough  122   c . The preset space is configured to accommodate the signal collecting portion  112  (for example, the sampling wire  112   a ) between the first connecting section  122   a  and the second connecting section  122   b.    
     In some embodiments, as shown in  FIG. 10  to  FIG. 12 , the connecting part  12  further includes a buffer portion  123 . The buffer portion  123  is located between the connecting portion  122  and the body portion  121 , and is connected to both of them. The buffer portion  123  can deform when receiving a force. For example, as shown in  FIG. 5 , the connecting portion  122  and the body portion  121  are arranged along the width direction Y of the battery module M 2 . Therefore, the buffer portion  123  can deform along the width direction Y. When the battery module M 2  vibrates during operation, the deformation of the buffer portion  123  can cushion an impact load received by the connecting part  12 . In addition, when the battery module M 2  expands during operation, the connecting part  12  receives an expansion force. In this case, the deformation of the buffer portion  123  can cushion the expansion force received by the connecting part  12 , thereby reducing risks of disconnection between the connecting part  12  and the circuit board  11 . 
     Specifically, as shown in  FIG. 10  to  FIG. 12 , the buffer portion  123  may include a plurality of bend structures  123   a . The bend structures  123   a  protrude in a height direction Z (the thickness direction Z of the sampling component  1 ). Therefore, when a force received by the connecting part  12  leads to a tendency of moving far away from each other between the connecting portion  122  and the body portion  121 , the bend structure  123   a  can deform, thereby compensating for the deformation of the connecting portion  122  and the body portion  121 , and preventing decrease of reliability of connection between the connecting part  12  and the circuit board  11  caused by the pulling between the connecting portion  122  and the body portion  121 . 
     More specifically, as shown in  FIG. 10  to  FIG. 12 , a gap  123   b  exists between adjacent bend structures  123   a . The gap  123   b  makes the bend structures  123   a  be spaced apart from each other so that the buffer portion  123  is easily deformable, thereby improving the reliability of connection between the connecting part  12  and the circuit board  11 . In addition, the gap  123   b  between the adjacent bend structures  123   a  can reduce a weight of the connecting part  12 , thereby increasing an energy density of the battery module M 2 . 
     In some embodiments, as shown in  FIG. 10  to  FIG. 12 , the connecting part  12  may further include a transition portion  124 . The transition portion  124  is located between the connecting portion  122  and the buffer portion  123 , and is connected to both of them. Specifically, the transition portion  124  may be a tapered structure. In a direction from the buffer portion  123  to the connecting portion  122 , a cross-sectional area of the transition portion  124  gradually decreases, so that two ends of the transition portion  124  can fit with both the buffer portion  123  and the connecting portion  122 . 
     More specifically, as shown in  FIG. 11 , a reinforcing structure  124   a  may be disposed on the transition portion  124 . The reinforcing structure  124   a  can be used to increase strength of the connecting portion  122  and the transition portion  124 , reduce risks of deformation of the connecting portion  122 , and thereby improve the reliability of connection between the connecting portion  122  and the circuit board  11 . The reinforcing structure  124   a  may be arc-shaped. The reinforcing structure  124   a  of the arc-shaped structure can reduce concentration of stress, and thereby increase the strength and rigidity of the connecting part  12 . 
     In another embodiment, as shown in  FIG. 10  to  FIG. 12 , a limiting structure  121   a  is disposed on the body portion  121  of the connecting part  12 . Specifically, the limiting structure  121   a  may be a sheet-like structure extending downward, Correspondingly, as shown in  FIG. 5  and  FIG. 6 , a limiting hole  21  is opened on the connecting plate  2  of the battery module M 2 . At least a part of the limiting structure  121   a  can extend into the limiting hole  21  and fit with the limiting hole  21 . 
     In the above embodiments, as shown in  FIG. 6 , in the battery module M 2 , along the height direction Z, the connecting part  12  is located between the connecting plate  2  and the sampling component  1 , and the connecting part  12  is connected to the circuit board  11  (mechanically and electrically). In addition, the connecting part  12  is connected to the connecting plate  2 , and specifically, may be connected by welding. In this way, electrical connection is implemented between the connecting plate  2  and the circuit board  11 , and the circuit board  11  can collect information about each battery cell  5  through the connecting plate  2 . 
     Specifically, through coordination between the limiting structure  121   a  and the limiting hole  21 , relative movement between the connecting part  12  and the connecting plate  2  is restricted before welding the connecting part  12  to the connecting plate  2 , thereby improving reliability of the welding between them. 
     In the above embodiments, the connecting part  12  may be made of a material of a copper-nickel alloy (cupronickel). The copper-nickel alloy is a copper-based alloy in which nickel is a main additive element, where the content of nickel may be adjusted according to actual needs. When the connecting part  12  is made of a material of a copper-nickel alloy, the connecting part  12  is of relatively high ductility and strength, thereby facilitating crimping, improving the reliability of the connection between the connecting part  12  and the signal collecting portion  112 , and enabling welding of the connecting part  12  to the connecting plate  2  (the connecting plate  2  may be made of an aluminum material). 
     Therefore, in this embodiment, the reliability of connection is relatively high between the connecting part  12  and the connecting plate  2 , and between the connecting part and the signal collecting portion  112 . 
     The foregoing descriptions are merely exemplary embodiments of this application, but are not intended to limit this application. A person skilled in the art understands that this application may have various modifications and variations. Any modification, equivalent replacement, improvement, and the like made without departing from the spirit and principles of this application fall within the protection scope of this application.