Electrochemical device and electric apparatus

Abstract

The utility model relates to electrochemical device and electric equipment, including two steel shell electric core of side by side arrangement, the shell of two steel shell electric core is connected through negative electrode electrode holder, the steel shell electric core is equipped with the end face of positive electrode terminal end face, the fixedly installed protection board support is equipped on the electric core end face, the protection board support is equipped with the let -go hole of positive electrode terminal let -go cooperation, the protection board support is connected with the protection board through a plurality of support column, the height of support column opposite electric core end face is H3, the height of positive electrode terminal opposite electric core end face is H1, satisfy H3>H1, the protection board is equipped with the connecting pad for electric connection protection board and steel shell electric core between electric core end face.

Description

Technical Field

[0001] This utility model relates to the field of battery cell packaging, and more particularly to electrochemical devices and electrical equipment. Background Technology

[0002] In existing technologies, the positive terminal of a steel-cased battery cell typically protrudes from the end face of the cell. When two steel-cased cells need to be connected in parallel, the protection board is usually fixed using adhesive. Due to the protruding structure of the positive terminal, the protection board lacks a relatively flat mounting surface. Furthermore, the protection board itself contains many electrical components and is not perfectly flat. Additionally, the pads on the protection board that are welded to the positive and negative terminals of the steel-cased battery cell need to be bent to reduce space occupation. However, the stability of the bent pads is poor, which may affect the fixation of the protection board. Moreover, the height controllability of the bent pads is poor. On the one hand, this leads to poor installation and fixation of the protection board; on the other hand, it results in a large installation error in the height of the protection board relative to the end face of the battery cell, reducing product consistency. Utility Model Content

[0003] To address the aforementioned problems in the prior art, this invention provides an electrochemical device.

[0004] To achieve the above objectives, the main technical solutions adopted by this utility model include:

[0005] An electrochemical device includes two steel-cased battery cells arranged side by side; the outer shells of the two steel-cased battery cells are electrically connected by a negative electrode welding rod; the end face of each steel-cased battery cell with a positive terminal is called the cell end face; a protective plate bracket is fixedly mounted on the cell end face; the protective plate bracket has a clearance hole that mates with the positive terminal; the protective plate bracket is connected to a protective plate by several support columns; the height of the support columns relative to the cell end face is H3, and the height of the positive terminal relative to the cell end face is H1, satisfying H3 > H1; a connecting pad for electrically connecting the protective plate and the steel-cased battery cells is provided between the protective plate and the cell end face.

[0006] In one embodiment of this utility model, the outer shell of the steel-shell battery cell constitutes the negative electrode; two negative electrode welding rods are provided, one on the end face of the battery cell and the other on the bottom face opposite to the end face of the battery cell.

[0007] In one embodiment of this utility model, the front and back sides of the steel-cased battery cell are arranged back to back to reduce the distance between the two positive terminals.

[0008] In one embodiment of this utility model, the protection plate bracket is fixedly connected to the end face of the battery cell by fixing a sticker.

[0009] In one embodiment of the present invention, the two opposite sides of the clearance hole extend toward the side away from the end face of the battery cell to form opposing baffles; at least a portion of the connecting pads are located between the baffles and connected to the positive terminal.

[0010] In one embodiment of this utility model, the two baffles are arranged opposite to each other along the thickness direction of the steel-shell battery cell; the height of the baffle relative to the end face of the battery cell is H2, which satisfies H3>H2>H1.

[0011] In one embodiment of this utility model, the connecting pad includes a first welding part electrically connected to the protection plate and a second welding part electrically connected to the steel shell battery cell; the first welding part and the second welding part are connected by a bending part; when the protection plate is connected to the protection plate bracket, the bending part is at least partially located in the space between the protection plate and the battery cell end face.

[0012] In one embodiment of this utility model, the bending portion includes a first bending portion, a second bending portion, and a third bending portion connected in sequence; the first bending portion is connected to a first welding portion; the third bending portion is connected to a second welding portion; the first bending portion has an arc-shaped portion and the center of curvature of the arc-shaped portion faces towards the center of the protective plate; the second bending portion has an arc-shaped portion and the center of curvature of the arc-shaped portion faces away from the center of the protective plate; the third bending portion has an arc-shaped portion and the center of curvature of the arc-shaped portion faces towards the center of the protective plate; the connecting pads include a positive electrode pad and a negative electrode pad; two positive electrode pads are provided, and one negative electrode pad is provided.

[0013] In one embodiment of this utility model, the electrical components on the protection board are arranged on the side of the protection board near the end face of the battery cell; a flexible board is also connected to the protection board; the connection end of the flexible board and the protection board is located on the side of the protection board near the end face of the battery cell; the side of the protection board away from the end face of the battery cell is covered with a protective board shell connected to the steel-cased battery cell.

[0014] An electrical device, comprising the aforementioned electrochemical apparatus.

[0015] The beneficial effects of this utility model are as follows: by setting a protection plate bracket on the end face of the battery cell and designing the support column height to be greater than the height of the positive terminal, a flat installation base is provided for the protection plate, effectively avoiding the problem of unstable fixation caused by the protrusion of the positive terminal; at the same time, the optimized arrangement of the connecting pads ensures the reliability of the electrical connection, significantly improves the consistency and compactness of the product, and has the advantages of reliable installation, high product consistency, and compact structure. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this utility model and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.

[0017] Figure 1 This is an exploded view of the present invention;

[0018] Figure 2 This is an assembly diagram of the present invention;

[0019] Figure 3 yes Figure 2 Enlarged diagram of section A in the middle;

[0020] Figure 4 This is a perspective view of the protective plate of this utility model;

[0021] Figure 5 yes Figure 4 Enlarged schematic diagram of section B in the middle.

[0022] Explanation of reference numerals in the attached figures:

[0023] 100. Steel-cased battery cell; 101. Battery cell end face; 102. Bottom end face; 110. Positive terminal; 111. Negative electrode welding rod; 120. Fixing sticker; 130. Protection board bracket; 131. Clearance hole; 132. Baffle; 133. Support column; 140. Protection board; 150. Connecting pad; 151. Positive electrode pad; 152. Negative electrode pad; 153. First welding part; 154. Second welding part; 155. Bending part; 1551. First bending part; 1552. Second bending part; 1553. Third bending part; 160. Flexible circuit board; 170. Protection board outer shell. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model. Therefore, the following detailed description of the embodiments of this utility model provided in the accompanying drawings is not intended to limit the scope of the claimed utility model, but merely to represent selected embodiments of this utility model.

[0025] In the description of this utility model, it should be noted that the terms "upper," "lower," "inner," "outer," "front end," "rear end," "both ends," "one end," and "the other end," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. In addition, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0026] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installed," "equipped with," "connected," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0027] Examples, such as Figure 1-5 As shown:

[0028] An electrochemical device includes two steel-cased battery cells 100 arranged side by side; the outer shells of the two steel-cased battery cells 100 are electrically connected by a negative electrode welding rod 111; the end face of the steel-cased battery cell 100 with a positive terminal 110 is called the battery cell end face 101; a protection plate bracket 130 is fixedly mounted on the battery cell end face 101; the protection plate bracket 130 has a clearance hole 131 that mates with the positive terminal 110; a protection plate 140 is connected to the protection plate bracket 130 by several support columns 133; the height of the support columns 133 relative to the battery cell end face 101 is H3, and the height of the positive terminal 110 relative to the battery cell end face 101 is H1, satisfying H3 > H1; a connection pad 150 for electrically connecting the protection plate 140 and the steel-cased battery cell 100 is provided between the protection plate 140 and the battery cell end face 101.

[0029] The cell end face 101 refers to the end surface of the steel-cased cell 100 where the positive terminal 110 is located. Furthermore, the protection plate bracket 130 is fixed to the cell end face 101, primarily to form a rigid support platform to avoid physical interference with the positive terminal 110. The clearance hole 131 on the protection plate bracket 130 is used to mate with the positive terminal 110. This hole can be circular, elliptical, or irregularly shaped, for example, the hole size can be customized according to the geometric contour of the positive terminal 110. This is mainly to ensure a smooth and flush fit between the bracket and the cell end face 101 without creating installation gaps. In a preferred embodiment, the protection board bracket 130 is connected to the protection board 140 via several support columns 133. The height H3 of the support columns 133 relative to the cell end face 101 is set to be greater than the height H1 of the positive terminal 110 relative to the cell end face 101. Specifically, the height difference can be controlled by selecting metal or plastic columns of standard height, thereby ensuring that the protection board 140 is completely located in the space above the positive terminal 110 to avoid installation errors caused by physical contact. Furthermore, a connection pad 150 is provided between the protection board 140 and the cell end face 101 for electrically connecting the protection board 140 and the steel-cased cell 100. In practical applications, this pad can be implemented by direct welding of metal sheets or bonding with conductive adhesive. For example, copper foil can be fixed between the protection board 140 and the cell end face 101 by hot pressing. This is mainly to simplify the electrical connection path and enhance mechanical stability. This application provides a flat and stable installation base for the protective plate 140 through the coordinated structural design of the protective plate bracket 130 and the support column 133. At the same time, by using the setting that the height difference H3 is greater than H1, the influence of the protruding structure of the positive terminal 110 is effectively avoided. Thus, the problems of poor fixing effect, poor height controllability and reduced product consistency caused by uneven installation surface in the prior art are systematically solved.

[0030] In one embodiment of the present invention, the outer shell of the steel-shell battery cell 100 constitutes the negative electrode; two negative electrode welding rods 111 are provided, one on the end face 101 of the battery cell and the other on the bottom end face 102 opposite to the end face 101 of the battery cell.

[0031] Among them, the outer shell of the steel-cased battery cell 100 constitutes the negative electrode, which means that the metal outer shell of the battery cell directly serves as the negative electrode conductive path. The purpose is to simplify the negative electrode lead-out path of the battery cell and avoid setting up an additional independent negative terminal. The negative electrode welding rod 111 is provided with two metal strips or sheets with good conductivity as the connection medium. Specifically, copper strip, aluminum strip or nickel-plated steel strip and other materials can be selected.

[0032] Specifically, the solution in this application uses negative electrode welding rods 111 at two positions on the cell end face 101 and bottom end face 102, connecting the negative electrodes of the cell together in parallel within the battery casing. During the installation of the protection board 140, the negative electrode welding rods 111 on the bottom end face 102 and the negative electrode welding rods 111 on the cell end face 101 work together to constrain the vertical displacement of the cell. Since the height H3 of the support column 133 needs to be greater than the height H1 of the positive terminal 110 to allow space for the bending of the welding pad, the dual-position welding rod design ensures that the connection stress is evenly distributed along the height direction of the cell, avoiding local deformation caused by single-point connection, thereby ensuring the relative positional accuracy between the protection board bracket 130 and the cell end face 101.

[0033] In one embodiment of this utility model, the front and back sides of the steel-cased battery cell 100 are arranged back to back to reduce the distance between the two positive terminals 110.

[0034] This solution optimizes the distance between the positive terminals 110 by adjusting the relative orientation of the two steel-cased cells 100. Specifically, "front and back facing" refers to the front side of one steel-cased cell 100 (the large surface connected to the cell end face 101, as shown in the attached diagram). Figure 1 The two steel-cased cells 100 are arranged opposite each other. The steel-cased cells 100 typically include a protruding positive terminal 110, and the outer casing of the steel-cased cells 100 forms the negative terminal. The positive terminal 110 is generally offset on the end face 101 of the cell. By arranging the positive and negative sides of the two steel-cased cells 100 back to back, the distance between the two positive terminals 110 can be kept to a minimum, thereby reducing the length of the protection plate 140 and the space occupied on the end face 101 of the cell.

[0035] In one embodiment of this utility model, the protection board bracket 130 is fixedly connected to the cell end face 101 by a fixing sticker 120.

[0036] The fixing sticker 120 refers to an adhesive medium used to reliably fix the protection board bracket 130 to the cell end face 101. It can be implemented by double-sided tape or pressure-sensitive adhesive. Its purpose is to effectively compensate for the unevenness of the cell end face 101 caused by the protrusion of the negative electrode welding rod 111 by providing an adaptable adhesive layer, thereby reducing the installation height error of the protection board bracket 130.

[0037] Specifically, the solution of this application uses a fixed sticker 120 as an intermediate medium between the protection board bracket 130 and the cell end face 101. Combined with the clearance hole 131 provided on the protection board bracket 130 to avoid the positive terminal 110, a relatively flat contact area is formed at the bottom of the bracket. The thickness of the fixed sticker 120 can be adapted to the height of the negative electrode welding rod 111 to ensure that the protection board bracket 130 maintains a horizontal posture during installation, avoids stress concentration caused by height differences, and thus improves the fixing stability.

[0038] The presence of the clearance hole 131 allows the protection board bracket 130 and the cell end face 101 to have a relatively flat contact surface, effectively fixing the protection board bracket 130. In one embodiment, the cell end faces 101 of the two steel-cased cells 100 are located on the same side and in the same horizontal plane. A negative electrode welding rod 111 is provided on the cell end face 101 between the two positive terminals 110 for electrically connecting the negative terminals of the two steel-cased cells 100. Since the negative electrode welding rod 111 has a certain height, the protrusion height of the protection board bracket 130 on the cell end face 101 can be reduced by setting the fixing sticker 120 at the positive terminal 110. At this time, the fixing sticker 120 is also provided with a through hole that allows the positive terminal 110 to pass through, that is, the fixing sticker 120 is arranged around the positive terminal 110. The thickness of the fixing sticker 120 in the circumferential direction can be selected to be similar to the thickness of the negative electrode welding rod 111, thereby ensuring effective adhesion between the middle part of the protection board bracket 130 and the negative electrode welding rod 111. The two ends of the protection board bracket 130 are fixedly connected to the end face 101 of the battery cell through the fixing sticker 120. In one embodiment, the thickness of the fixing sticker 120 can also be greater than the thickness of the negative electrode welding rod 111, and another fixing sticker 120 can be set on the negative electrode welding rod 111 to offset the thickness difference between the fixing sticker 120 and the negative electrode welding rod 111, thereby achieving a larger area of ​​adhesion at the bottom of the protection board bracket 130. The fixing sticker 120 is usually double-sided adhesive. In one embodiment, the fixing sticker 120 can also be set only on the negative electrode welding rod 111 to achieve adhesion to the protection board bracket 130.

[0039] In one embodiment of the present invention, two opposite sides of the clearance hole 131 extend toward the side away from the end face 101 of the battery cell and form opposing baffles 132; at least a portion of the connecting pad 150 is located between the baffles 132 and connected to the positive terminal 110.

[0040] Specifically, baffle 132 refers to a limiting structure extending from the side of relief hole 131, which is intended to constrain the lateral movement range of connecting pad 150; wherein, connecting pad 150 can be understood as a conductive component for electrical connection, which is intended to achieve reliable electrical connection between protection plate 140 and positive terminal 110.

[0041] Specifically, the solution of this application constructs an enclosed space above the end face 101 of the battery cell by extending the relative baffle 132 from the side of the clearance hole 131. This restricts the movement of the connecting pad 150 in the lateral direction, so that the connecting pad 150 is forcibly fixed in the preset position after bending. It can also effectively and quickly position the connecting pad 150, so that it can quickly and effectively dock with the positive terminal 110, which facilitates subsequent welding work and ensures the precise alignment and stability of the welding point.

[0042] In one embodiment of this utility model, two baffles 132 are arranged opposite to each other along the thickness direction of the steel shell cell 100; the height of the baffle 132 relative to the end face 101 of the cell is H2, which satisfies H3>H2>H1.

[0043] Among them, baffle 132 refers to the structure formed by extending from the side opposite to the clearance hole 131 toward the side away from the end face 101 of the cell, so as to provide a lateral limiting function for the connecting pad 150, the purpose of which is to constrain the lateral displacement of the pad during the installation process; the baffle 132 is set opposite to each other along the thickness direction of the steel shell cell 100, which means that the two baffles 132 are symmetrically distributed in the narrowest dimension of the cell, which can be achieved by parallel extension or micro-arc extension, the purpose of which is to form a uniform lateral support force by utilizing the spatial compactness in the thickness direction of the cell; the height H2 of the baffle 132 relative to the end face 101 of the cell satisfies H3>H2>H1, which means that the value range of H2 is strictly limited between the height H1 of the positive terminal 110 and the height H3 of the support column 133, it can be set to an intermediate value that is slightly higher than H1 but lower than H3, the purpose of which is to ensure that the baffle 132 effectively covers the positive terminal 110 while reserving the installation gap of the protection plate 140.

[0044] Specifically, the solution of this application sets two baffles 132 opposite to each other along the thickness direction of the steel-shell cell 100, so that the baffles 132 form a symmetrical constraint structure in the thickness direction of the cell, providing uniform lateral support force for the connecting pads 150, which can facilitate the rapid positioning of the connecting pads 150 and facilitate welding; at the same time, by limiting H2 to satisfy H3 > H2 > H1, it is ensured that H2 is greater than H1 to completely cover the positive terminal 110 and most of the connecting pads 150, reducing the exposed area of ​​the pads and avoiding external interference; if H2 is less than H3, a stable gap space is formed between the protection plate 140 and the cell end face 101, so that the bent part 155 of the connecting pads 150 can be reliably accommodated, avoiding collision between the protection plate 140 and the baffles 132 during installation, thereby reducing the assembly error in the height direction.

[0045] In one embodiment of the present invention, the connecting pad 150 includes a first welding portion 153 electrically connected to the protection plate 140 and a second welding portion 154 electrically connected to the steel shell battery cell 100; the first welding portion 153 and the second welding portion 154 are connected by a bending portion 155; when the protection plate 140 is connected to the protection plate bracket 130, the bending portion 155 is at least partially located in the space between the protection plate 140 and the battery cell end face 101.

[0046] Specifically, the first welded part 153 refers to the structural part that establishes an electrical connection with the protective plate 140, with the purpose of ensuring a stable connection at the end of the protective plate 140; the second welded part 154 refers to the structural part that establishes an electrical connection with the steel-shell battery cell 100; in practical applications, the bent part 155 refers to the transition structure connecting the first welded part 153 and the second welded part 154, which can be achieved by using a single bend or a multi-segment continuous bend of metal sheet, with the purpose of adapting to installation space constraints and providing the necessary elastic deformation capacity; specifically, the bent part 155 being at least partially located in the space between the protective plate 140 and the battery cell end face 101 means that the bent structure is constrained in the gap formed by the protective plate 140 and the battery cell end face 101, which can be achieved by natural bending or a preset bending angle, with the purpose of using this gap to reduce the occupation of the overall thickness and improve height controllability.

[0047] Specifically, the solution of this application optimizes the pad structure by designing the connecting pad 150 to include a first welding portion 153, a second welding portion 154, and a bent portion 155 connecting the two, and ensuring that the bent portion 155 is at least partially located within the space between the protection plate 140 and the cell end face 101 during installation. The first welding portion 153 is electrically connected to the protection plate 140, the second welding portion 154 is electrically connected to the steel-cased cell 100, and the bent portion 155 serves as a transition structure to adapt to the installation space. When the protection plate 140 is connected to the protection plate bracket 130, the bent portion 155 is constrained within the inherent gap formed between the protection plate 140 and the cell end face 101. The height of this gap is determined by the difference between the height H3 of the support column 133 and the height H1 of the positive terminal 110, thereby naturally limiting the bending degree of the bent portion 155, making the height more precise and controllable, reducing installation positioning errors, and avoiding the adverse effects of stress on the fixation of the protection plate 140.

[0048] like Figure 5As shown, in one embodiment of this utility model, the bending portion 155 includes a first bending portion 1551, a second bending portion 1552, and a third bending portion 1553 connected in sequence; the first bending portion 1551 is connected to the first welding portion 153; the third bending portion 1553 is connected to the second welding portion 154; the first bending portion 1551 has an arc-shaped portion and the center of curvature of the arc-shaped portion faces towards the center of the protective plate 140; the second bending portion 1552 has an arc-shaped portion and the center of curvature of the arc-shaped portion faces away from the center of the protective plate 140; the third bending portion 1553 has an arc-shaped portion and the center of curvature of the arc-shaped portion faces towards the center of the protective plate 140; the connecting pad 150 includes a positive electrode pad 151 and a negative electrode pad 152; a pre-formed ... The designed bending area facilitates rapid bending and installation after welding. The second bending portion is preferably entirely housed within the space between the protective plate 140 and the cell end face 101, thereby reducing the occupancy of the steel-cased cell 100 in the thickness direction. On the other hand, in the solution of this application, the protective plate 140 has a more stable installation position and can be fixed more stably and flatly. In one embodiment, the three bending portions can form a miniature spring, providing a certain supporting force after bending, making the connection stability between the first welding portion 153 and the protective plate 140, and the second welding portion 154 and the positive terminal 110 better. Even if welding problems occur, the electrical connection can still be maintained effectively by utilizing the elastic pressing of the pads. Two positive electrode pads 151 are provided, and one negative electrode pad 152 is provided.

[0049] In one embodiment of the present invention, the electrical components on the protection plate 140 are arranged on the side of the protection plate 140 near the end face 101 of the battery cell; a flexible board 160 is also connected to the protection plate 140; the connection end between the flexible board 160 and the protection plate 140 is located on the side of the protection plate 140 near the end face 101 of the battery cell; the side of the protection plate 140 away from the end face 101 of the battery cell is covered with a protection plate outer shell 170 connected to the steel-cased battery cell 100.

[0050] Specifically, the electrical component configuration position on the protection board 140 refers to the mounting orientation of the electrical components on the protection board 140. This can be achieved by directly soldering the electrical components to the surface of the protection board 140 facing the cell end face 101, in order to reduce the space occupied between the protection board 140 and the cell end face 101 and avoid forming additional protrusions on the opposite side. The flexible circuit board 160 refers to a flexible printed circuit board, which can be made of polyimide substrate. Its purpose is to provide a signal transmission path and adapt to spatial bending requirements. In practical applications, the connection point between the flexible circuit board 160 and the protection board 140... This refers to the specific location of the electrical connection between the flexible circuit board 160 and the protection board 140. It can be achieved by using surface mount technology to fix the connection end on the surface of the protection board 140 facing the end face 101 of the battery cell. The purpose is to avoid the connection end occupying the space on the opposite side and to maintain a thin design. Specifically, the protection board shell 170 refers to the fixing structure covering the protection board 140, which can be formed by injection molding. In a simplified embodiment, the protection board shell 170 can also be a U-shaped adhesive structure formed by insulating adhesive, which covers the protection board 140 and connects to the end face of the steel-cased battery cell 100 at the same time to fix the protection board 140.

[0051] In another embodiment, this application also discloses an electrical device including the aforementioned electrochemical device. As an application carrier, the reliability of this electrical device highly depends on the stable integration of the electrochemical device. The core innovation of this embodiment lies in effectively avoiding the unevenness of the mounting surface caused by the protrusion of the positive terminal 110 by combining the flat mounting base of the protection plate bracket 130 with the height difference design of the support column 133, and precisely controlling the mounting height of the protection plate 140.

[0052] The above description is merely an embodiment of this application and is not intended to limit the scope of protection of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. An electrochemical device, characterized in that: It includes two steel-cased battery cells (100) arranged side by side; the outer shells of the two steel-cased battery cells (100) are electrically connected by a negative electrode welding rod (111); the end face of the steel-cased battery cell (100) with a positive terminal (110) is a battery cell end face (101); a protection plate bracket (130) is fixedly provided on the battery cell end face (101); the protection plate bracket (130) is provided with a clearance hole (131) that cooperates with the positive terminal (110); the protection plate bracket (130) is a protective plate bracket (130) with a clearance hole (131) that cooperates with the positive terminal (110); the protection plate bracket (130) is a protective plate bracket (111) with a positive terminal (110) and ...0) with a positive terminal (110) and a protective plate bracket (110) with a positive terminal (110) and a protective plate bracket (110) with a positive terminal (110) and a protective plate bracket (110) with a positive terminal ( The board support (130) is connected to the protection plate (140) by a number of support columns (133); the height of the support column (133) relative to the end face (101) of the cell is H3, and the height of the positive terminal (110) relative to the end face (101) of the cell is H1, satisfying H3>H1; the protection plate (140) and the end face (101) of the cell are provided with a connection pad (150) for electrically connecting the protection plate (140) and the steel shell cell (100).

2. The electrochemical device according to claim 1, characterized in that: The outer shell of the steel-shell battery cell (100) forms the negative electrode; two negative electrode welding rods (111) are provided, one on the end face (101) of the battery cell and the other on the bottom end face (102) opposite to the end face (101) of the battery cell.

3. The electrochemical device according to claim 1, characterized in that: The steel-cased battery cell (100) is arranged with its front and back sides facing each other to reduce the distance between the two positive terminals (110).

4. The electrochemical device according to claim 1, characterized in that: The protection board bracket (130) is fixedly connected to the end face (101) of the battery cell by a fixing sticker (120).

5. The electrochemical device according to claim 1, characterized in that: The two opposite sides of the clearance hole (131) extend toward the side away from the end face (101) of the battery cell and form opposing baffles (132); at least a portion of the connecting pads (150) are located between the baffles (132) and connected to the positive terminal (110).

6. The electrochemical device according to claim 5, characterized in that: The two baffles (132) are arranged opposite each other along the thickness direction of the steel-shell battery cell (100); the height of the baffle (132) relative to the end face (101) of the battery cell is H2, which satisfies H3>H2>H1.

7. The electrochemical device according to claim 1, characterized in that: The connecting pad (150) includes a first welding part (153) electrically connected to the protection plate (140) and a second welding part (154) electrically connected to the steel shell cell (100); the first welding part (153) and the second welding part (154) are connected by a bending part (155); when the protection plate (140) is connected to the protection plate bracket (130), the bending part (155) is at least partially located in the space between the protection plate (140) and the cell end face (101).

8. The electrochemical device according to claim 7, characterized in that: The bending portion (155) includes a first bending portion (1551), a second bending portion (1552), and a third bending portion (1553) connected in sequence; the first bending portion (1551) is connected to the first welding portion (153); the third bending portion (1553) is connected to the second welding portion (154); the first bending portion (1551) has an arc-shaped portion and the center of curvature of the arc-shaped portion faces towards the center of the protective plate (140); the second bending portion (1552) has an arc-shaped portion and the center of curvature of the arc-shaped portion faces away from the center of the protective plate (140); the third bending portion (1553) has an arc-shaped portion and the center of curvature of the arc-shaped portion faces towards the center of the protective plate (140); the connecting pad (150) includes a positive electrode pad (151) and a negative electrode pad (152); two positive electrode pads (151) are provided, and one negative electrode pad (152) is provided.

9. The electrochemical device according to claim 1, characterized in that: The electrical components on the protection board (140) are arranged on the side of the protection board (140) close to the end face (101) of the battery cell; a flexible board (160) is also connected to the protection board (140); the connection end of the flexible board (160) and the protection board (140) is located on the side of the protection board (140) close to the end face (101) of the battery cell; the side of the protection board (140) away from the end face (101) of the battery cell is covered with a protective board shell (170) connected to the steel-cased battery cell (100).

10. An electrical appliance, characterized in that, Includes the electrochemical device as described in any one of claims 1 to 9.

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