Composite energy storage battery busbar and composite energy storage battery

Abstract

The invention discloses a composite energy storage battery busbar and an energy storage battery, and belongs to the field of lead energy storage batteries. The battery busbar comprises a conductive binding post, a screw joint part and a confluence grating; the screw joint part is a trapezoidal block, one side of the short edge of the trapezoidal block is connected with the bottom of the conductive binding post, and one side of the long edge is connected with the confluence grid; the confluence grating comprises a plurality of conductive ribs and a confluence area connected with one ends of the conductive ribs at the same time. The length of each conductive rib connected with the confluence area is gradually increased from the center of the confluence area to the two sides. According to the invention, the conductive ribs are transversely connected by using the transverse grid ribs in the confluence grid, so that the problem of non-uniform charging and discharging of each area of the battery unit caused by non-uniform charging and discharging of the conductive ribs is solved, and the battery loss is reduced; and meanwhile, the lengths of the conductive ribs are adjusted based on the positions of the conductive ribs relative to the convergence region, so that the current transmission path is optimized, the loss is reduced, and the service life and the stability of the battery are improved.

Description

Technical Field

[0001] The present invention relates to the field of energy storage batteries, and particularly to a busbar for a composite energy storage battery and a composite energy storage battery. Background Art

[0002] Energy storage batteries mainly refer to batteries used in solar power generation equipment, wind power generation equipment, and renewable energy storage. They have the advantages of high energy density, good safety performance, long cycle life, fast charge and discharge ability, low self-discharge rate, and environmental friendliness.

[0003] In the prior art, for the busbar of an energy storage battery, on the one hand, the current difference between the input end and the output end of the busbar and the maximum conductive strength of the overall grid are not considered, resulting in large power losses and poor charging uniformity in each area of the battery. On the other hand, the battery busbar adopts a split forming technology, and each component needs to be formed by means of lead alloy. In the prior art, a large amount of lead alloy is used to increase the connection strength, and there are disadvantages such as series connection of adjacent connection structures and expansion to the surrounding areas and uneven charging in each area of the busbar, which do not meet the design requirements of improving the safety and miniaturization of the battery. Currently, there is an urgent need in the market for a busbar with low loss, high reliability, uniform charging, and suitable for high-power composite energy storage batteries. Summary of the Invention

[0004] In view of the above analysis and the deficiencies in the prior art, the present invention aims to provide a busbar for a composite energy storage battery and a composite energy storage battery, so as to solve at least one of the problems such as large power loss of the battery busbar, series connection of adjacent connection structures and expansion to the surrounding areas, and poor charging uniformity in each area of the battery.

[0005] The object of the present invention is mainly achieved through the following technical solutions:

[0006] The present invention discloses a busbar for a composite energy storage battery, including a conductive terminal, a screwing portion, and a current collecting grid;

[0007] The screwing portion is a trapezoidal block, and one side of the short side of the trapezoidal block is connected to the bottom of the conductive terminal, and one side of the long side is connected to the current collecting grid.

[0008] Preferably, a plurality of conductive rib strips are provided and arranged in parallel. One ends of the plurality of conductive rib strips are simultaneously connected to the current collecting area, and the other ends form free ends. Each conductive rib strip can separately collect the current in each area.

[0009] Preferably, a transverse grid rib is provided between the connection end of the conductive rib strip and the current collecting area and the free end of the conductive rib strip, and the transverse grid rib sequentially connects each conductive rib strip.

[0010] Preferably, the lengths of the conductive rib strips connected to the current collecting area gradually increase from the center of the current collecting area to both sides.

[0011] Preferably, the busbar grid further includes transverse grid ribs which horizontally connect each conductive rib in the areas far from both ends of the conductive rib.

[0012] Preferably, an inwardly concave arc-shaped connecting portion is provided on one side of the short side of the trapezoidal block; the diameter of the arc-shaped connecting portion matches the outer diameter of the conductive connection post, and the arc-shaped connecting portion arc-covers the outer wall of the conductive connection post in the area where it is connected to the conductive connection post.

[0013] Preferably, the trapezoidal block is a trapezoidal block with uniform thickness at the top and bottom surfaces.

[0014] Preferably, the top and bottom surfaces of the trapezoidal block are perpendicular to the side surface of the busbar grid near the trapezoidal block, and the top and bottom surfaces of the trapezoidal block are perpendicular to the side surface of the connection pole post.

[0015] Preferably, the bottom surface of the conductive connection post is flush with the bottom surface of the trapezoidal block, and the top end surface of the busbar grid is flush with the top surface of the trapezoidal block.

[0016] Preferably, the conductive connection post includes a column body and a core body;

[0017] The column body is provided with an inwardly concave chamber, the core body is nested into the inwardly concave chamber of the column body, and the outer wall of the core body is connected to the inner wall of the column body in a matching manner.

[0018] Preferably, a screw hole is provided in the central depression area of the core body.

[0019] Preferably, one or more annular grooves are provided on the outer periphery of the column body, and annular O-rings are provided in the annular grooves in a matching manner.

[0020] A composite energy storage battery uses the above-mentioned battery busbar.

[0021] Compared with the prior art, the present invention can at least achieve one of the following beneficial effects:

[0022] 1. The present invention uses transverse grid ribs in the busbar grid to horizontally connect the conductive ribs, improves the problem of uneven charge and discharge of each area of the battery unit caused by uneven charge and discharge of the conductive ribs, and reduces battery loss.

[0023] 2. The present invention uses a busbar to converge the currents of battery units in each area, and solves the problem of uneven distribution of output and input currents caused by setting a single tab (busbar joint) in the prior art. Compared with the single tab of the traditional energy storage battery plate, the tabs (busbar joints) of the composite energy storage battery are dozens or more, and each tab (busbar joint) is separately connected to the busbar. This design has uniform current distribution, high utilization rate of active materials, and strong large-current charge and discharge ability.

[0024] 3. In the present invention, the cross-sectional area of the conductive rib gradually increases from the free end to the end connected to the current collecting area as the current conducted through each part of the conductive rib increases, forming the thickness / cross-sectional area slope of the bus bar. The proportional relationship between the current density and the cross-section of the conductive bus bar is fully considered, so that the conductive current per square millimeter is the same. This not only realizes the control of the relationship between the internal resistance and the current distribution, but also gives full play to the utilization rate of the conductive alloy and the active material. Compared with the horizontal lead mesh battery, the loss increase caused by the increase of the incoming current is reduced, and at the same time, the raw materials are reduced compared with the conductive rib with uniform thickness, and the cost is reduced.

[0025] 4. Based on the position of each conductive rib relative to the current collecting area, the present invention adjusts the length of the conductive rib, optimizes the transmission path of the current of the conductive rib in the current collecting area, reduces the loss, makes the output of the battery cells in different areas more uniform, and helps to improve the service life and stability of the battery.

[0026] 5. Based on the position of each conductive rib relative to the current collecting area, the present invention adjusts the length of the conductive rib, optimizes the transmission path of the current of the conductive rib in the current collecting area, reduces the internal resistance of the battery, increases the specific energy, realizes cost reduction and efficiency improvement, and fully utilizes limited resources to improve the utilization rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The drawings are only for the purpose of showing specific embodiments and are not considered as a limitation of the present invention. Throughout the drawings, the same reference signs denote the same components.

[0028] Figure 1 is the front view of the current collecting grid of a composite energy storage battery according to the present invention;

[0029] Figure 2 is the side view of the current collecting grid of a composite energy storage battery according to the present invention;

[0030] Figure 3 is the top view of the current collecting grid of a composite energy storage battery according to the present invention;

[0031] Figure 4a is the front view of the current collecting bus bar of the composite energy storage battery of Embodiments 1-3 according to the present invention;

[0032] Figure 4b is the front view of the current collecting bus bar of the composite energy storage battery of Embodiments 4-6 according to the present invention;

[0033] Figure 5 is the top view of a current collecting bus bar of a composite energy storage battery according to the present invention;

[0034] Figure 6 is the side view of a current collecting bus bar of a composite energy storage battery according to the present invention;

[0035] Figure 7 is the top view of the screwing part according to the present invention;

[0036] Figure 8a Isometric view of the composite energy storage battery of Embodiment 2 of the present invention;

[0037] Figure 8b Isometric view of the composite energy storage battery of Embodiment 4 of the present invention;

[0038] Figure 9 Side view of a composite energy storage battery of the present invention;

[0039] Figure 10 is Figure 3 Cross-sectional view taken along line A-A of;

[0040] Figure 11 Graph showing the variation of the height H of the longitudinal axis center line of the conductive rib with the position of the conductive rib relative to the symmetry axis of the bus bar in Embodiment 2 of the present invention;

[0041] Figure 12a Graph of the cyclic test data of Embodiment 2;

[0042] Figure 12b Graph of the cyclic test data of Embodiment 4;

[0043] Figure 12c Graph of the cyclic test data of Comparative Example 4.

[0044] Reference numerals:

[0045] Bus bar 1, positive bus bar 1a, negative bus bar 1b;

[0046] Battery cell 2;

[0047] Electrode plate 3;

[0048] Bus bar joint 5, first bus bar joint 5a, second bus bar joint 5b;

[0049] Conductive terminal 01, column body 011, core body 012, screw hole 013;

[0050] Threaded joint part 02, arc-shaped connecting part 021;

[0051] Bus bar grid 03, bus bar area 031, conductive rib 032, transverse grid rib 033. Detailed implementation manners

[0052] In order to make the technical problems, technical solutions and beneficial effects solved by the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0053] As used throughout the text, the terms "top", "bottom", "above", "below", and "on" describe the relative positions of the components of the device, such as the relative positions of the top and bottom substrates inside the device. It is understood that the devices are multifunctional and independent of their orientation in space.

[0054] The height described in this article refers to the vertical distance relative to the bottom edge or bottom surface of the placement position in the figure, and does not limit the installation and use methods.

[0055] As Figures 1 - 10 shown, on the one hand, the present invention discloses a busbar for a composite energy storage battery, including a conductive terminal 01, a screwed part 02, and a busbar grid 03;

[0056] The screwed part 02 is a trapezoidal block, with the short side of the trapezoidal block connected to the bottom of the conductive terminal 01 and the long side connected to the busbar grid 03.

[0057] During implementation, the current converges and transmits from the busbar grid 03 to the conductive terminal 01. The long side is connected to the top of the busbar grid 03, and the bottom end is connected to the conductive terminal 01. The screwed part 02 can bridge the busbar grid 03 and the conductive terminal 01. The design of the trapezoidal block can save the usage amount of the material of the screwed part without increasing the voltage drop of current transmission.

[0058] Specifically, the busbar grid includes conductive ribs 032;

[0059] There are multiple conductive ribs 032 arranged in parallel. One end of the multiple conductive ribs 032 is simultaneously connected to the current collection area 031, and the other end forms a free end. Each conductive rib 032 can separately collect the current in each area;

[0060] Each conductive rib 032 is connected to multiple current collection joints 5, and the current converges on the conductive rib 032 through the current collection joints 5;

[0061] The current collection joints 5 are distributed along the length direction of the conductive rib. Each current collection joint 5 can separately collect the current of the battery cell 2.

[0062] In a preferred implementation, the busbar grid includes transverse grid ribs 033;

[0063] The transverse grid ribs 033 sequentially connect the respective conductive ribs 032.

[0064] Specifically, the height H3 of the center of the transverse grid rib 033 from the bottom edge of the busbar grid satisfies: H3 = (0.4 - 0.7)

[0065] × H2, where H2 is the height of the electrode plate connected by the conductive rib.

[0066] Specifically, the width of the horizontal grid ribs 033 can be selected from 4 mm to 8 mm.

[0067] Exemplarily, as Figure 1 shown, the height H3 from the center of the horizontal grid ribs 033 to the bottom edge of the current collecting grid satisfies 67.5 mm; the width of the horizontal grid ribs 033 satisfies 6 mm.

[0068] It should be noted that the horizontal grid ribs help to improve the loss caused by uneven current after the current collection of each conductive rib, help to improve the problem of uneven charge and discharge in each area of the battery unit connected by the conductive rib, and significantly reduce the heat release during the battery formation process, reduce the maximum temperature, and improve the low-temperature performance of the battery.

[0069] Preferably, the current collecting grid 03 further includes a current collecting area 031;

[0070] One end of the current collecting area 031 is fixed with a conductive rib 032, and the other end is connected to an external circuit.

[0071] Specifically, as Figure 9 shown, the conductive rib 032 is connected with a plurality of current collecting joints 5 from the free end to the end connected to the current collecting area 031, and is sequentially named the first current collecting joint 5a, the second current collecting joint 5b,..., the Nth current collecting joint.

[0072] The current collecting joint 5 collects the current and converges it on the conductive rib 032, so that the current flowing through the conductive rib 032 from the free end to the end connected to the current collecting area gradually increases.

[0073] Preferably, the cross-sectional area of the conductive rib 032 gradually increases from the free end to the end connected to the current collecting area 031, reducing the loss caused by the increasing current.

[0074] Specifically, the cross-sectional area S of each part of the conductive rib 032 satisfies: S≥U×n / (ρ×L0×I0), where U is the electromotive force of the battery unit where the conductive rib 032 is located, L0 is the distance between the first current collecting joint 5a and the second current collecting joint 5b; I0 is the current flowing through the current collecting joint 5 under the action of U; ρ is the resistivity of the conductive rib 032; n is the number of current collecting joints connected to the conductive rib 032.

[0075] It should be noted that the number of current collecting joints n is determined by the processing technology and the self-electrical loss of the current collecting joint. A large number of current collecting joints helps to reduce the self-loss, but brings higher processing difficulties (the current collecting joints are mostly composed of lead wires extended from the power supply electrode plate, so their own diameters limit the number and cannot be increased without limit). Therefore, n satisfies: the interval between adjacent current collecting joints is between 4.8 mm and 6.5 mm.

[0076] Preferably, the current collecting joints 5 are arranged at equal intervals, the current collecting joints 5 are evenly arranged on the electrode plate 3, and the interval between adjacent current collecting joints = the height H2 of the electrode plate / (n + 1).

[0077] As an example, Figure 9 As shown, the number of bus connectors on each conductive rib 032 is 14. On the one hand, one end of the bus connector 5 is connected to the electrode plate to divide the electrode plate into 15 highly uniform areas; on the other hand, the other end of the bus connector 5 is connected to the conductive rib 032, so that the conductive rib 032 continuously converges from the free end to the end connected to the bus area 031, collecting the output current from various parts of the electrode plate and transmitting it to the bus area 031.

[0078] Preferably, the cross-sectional area S of each portion of the conductive rib 032 changes continuously to satisfy: S=S0+(Smax-S0)×(L-L0) / (Lmax-L0);

[0079] Among them, L is the length of the conductive rib 032 from the free end, L0 is the distance between the first bus joint 5a and the second bus joint 5b, Lmax is the length of the conductive rib 032, S0 is the cross-sectional area of the free end, which can be set according to the design specifications and actual processing conditions; Smax is the cross-sectional area of the end where the conductive rib 032 is connected to the bus area 031, and Smax satisfies: Smax = S0 × n.

[0080] It can be understood that (Smax-S0) / (Lmax-L0) is the thickness / cross-sectional area variation slope of the busbar.

[0081] It should be noted that an excessively large S0 results in a width of the conductive rib 032 (e.g. Figure 2 As shown in w1), the cross-sectional area increases, and too small S0 leads to large loss of conductive ribs. S0 satisfies: S0 is 0.5mm 2 ~10mm 2 between.

[0082] Compared with the existing technology, Figure 2 It can be seen that the present invention forms a busbar thickness / cross-sectional area slope by gradually increasing the cross-sectional area of the conductive ribs from the free end to the end connected to the busbar as the conduction current increases at various locations of the conductive ribs. This fully considers the proportional relationship between the current density and the cross-sectional area of the conductive busbar, making the conductive current per square millimeter the same. This not only achieves the control of the relationship between internal resistance and current distribution, but also gives full play to the utilization rate of the conductive alloy and active material. Compared with the horizontal lead mesh battery, the increase in loss caused by the increase in the input current is reduced. At the same time, compared with the conductive ribs with uniform thickness, the raw materials are reduced, thereby reducing the cost.

[0083] Preferably, the length L of each conductive rib connected to the bus area 031 gradually increases from the center of the bus area 031 to both sides.

[0084] It should be noted that the distances from the tops of the conductive bars connected to the busbar area to the busbar area and the screwing part are different, and their paths in the busbar area are different, so the actual losses are different. It is easy to cause uneven output currents of the conductive bars, resulting in different output performances of the conductive bars, the busbar joints and the battery cells they are connected to. Over time, the losses and performance differences of the battery cells in different regions will be different, affecting the service life and stability.

[0085] Specifically, as Figure 11 shown, taking the straight line where the bottom edge of the conductive bar 032 is located as the abscissa, the intersection point of the longitudinal axis center line of the busbar 1 and the abscissa as the origin, and the height H of the conductive bar 032 at its longitudinal axis center line as the ordinate, a function relationship between H and X is constructed: H = aX 2 + bX + c, where a = 0.0025 - 0.005, b = -0.5 - -1, c = 170 - 180.

[0086] It should be noted that, as Figure 2 shown, the midpoint P of the line connecting the upper left and right vertices of the upper part of the conductive bar 032 is defined as the highest point of the conductive bar. The distance from the highest point of the conductive bar 032 to the bottom edge of the conductive bar 032 is the height H of the longitudinal axis center line of the conductive bar. At the same time, the midpoint of the top of the busbar area 031 is defined as O, and the height difference H1 between the top of the busbar area 031 and the highest point of each conductive bar. The line segment PO shows the equivalent busbar path of the conductive bar 032.

[0087] It can be understood that each conductive bar has a corresponding line segment PO representing its equivalent busbar path. Each equivalent busbar path converges from the center P point of the top of each conductive bar to the O point. For the sake of clear and concise expression, Figure 2 only one equivalent busbar path is schematically shown by the line segment PO in

[0088] The applicant's research found that setting the length of the conductive bar according to the above function relationship between H and X has lower power loss and output efficiency compared to setting the same height for each conductive bar, especially when H1 < 15 mm, it is particularly obvious.

[0089] It can be understood that H1 reflects the height of the busbar area 031. The smaller H1 is, the more helpful it is to reduce the volume of the busbar area 031 and even the busbar, reducing raw material consumption, but at the same time, it brings the defects of large current loss and uneven busbar of each conductive bar.

[0090] Compared with the prior art, the present invention adjusts the length of the conductive bar according to the position of each conductive bar relative to the busbar area, optimizes the transmission path of the current of the conductive bar in the busbar area, reduces the loss, makes the output of the battery cells in different regions more uniform, and helps to improve the service life and stability of the battery.

[0091] Specifically, one long side of the screwing part 02 is connected to the current collecting area 031 of the current collecting grid 03.

[0092] Compared with the prior art, the present invention uses a bus bar to collect the currents of battery cells in each area, and solves the problem of uneven distribution of output and input currents caused by setting a single tab (current collecting joint) in the prior art. Compared with the single tab of the traditional energy storage battery plate, the tabs of the composite energy storage battery are dozens or more, and each tab (current collecting joint) is separately connected to the bus bar. This design has a uniform current distribution, a high utilization rate of active materials, and a strong large-current charge and discharge capacity.

[0093] It should be noted that during cast welding, an externally exposed welding mark will be formed in the welding area. The welding mark is slightly higher than the current collecting area 031 and the trapezoidal block on both sides of it, forming a protrusion, which affects the flatness.

[0094] Preferably, the current collecting area 031 is fixedly connected to the trapezoidal block by cast welding, and an externally exposed welding mark is formed on the bottom side of the trapezoidal block in the connection area between the trapezoidal block and the current collecting area 031.

[0095] Compared with the prior art, in the present invention, forming an externally exposed welding mark on the bottom side of the trapezoidal block in the connection area between the trapezoidal block and the current collecting area can further ensure the flatness of the outside of the bus bar, save the space occupied by the battery, and effectively avoid the short circuit of the active material contacting the conductive electrode post due to the expansion of the welding mark.

[0096] Preferably, as Figure 5 shown, an inwardly concave arc-shaped connecting part 021 is provided on one short side of the trapezoidal block; the diameter of the arc-shaped connecting part 021 matches the outer diameter of the conductive connection post 01, and the arc-shaped connecting part 021 arc-encapsulates the outer wall of the conductive connection post 01 in the connection area with the conductive connection post 01.

[0097] Preferably, by way of example, as Figure 1 - Figure 4 shows, the trapezoidal block is a trapezoidal block with uniform thickness at the top and bottom surfaces.

[0098] Specifically, the short side length of the trapezoidal block is 20 mm to 30 mm, and the long side length of the trapezoidal block is

[0099] 40 mm to 70 mm, and the thickness of the trapezoidal block is 5 mm to 20 mm.

[0100] Preferably, the top and bottom surfaces of the trapezoidal block are perpendicular to the side surface of the current collecting grid near the trapezoidal block, and the top and bottom surfaces of the trapezoidal block are perpendicular to the side surface of the connection electrode post.

[0101] Preferably, the bottom surface of the conductive connection post 01 is flush with the bottom surface of the trapezoidal block, and the top end surface of the current collecting grid 03 is flush with the top surface of the trapezoidal block. This design can make the most of the internal space of the battery case and effectively improve the volume specific energy.

[0102] Preferably, the screwing part 02 and the conductive terminal 01 are integrally die-cast.

[0103] Specifically, as shown in FIG. 8, the conductive terminal 01 includes a column body 011 and a core body 012. The core body 012 is nested in the concave chamber of the column body 011, and the outer wall of the core body 012 is connected to the inner wall of the column body 011 in a matching manner to achieve a good conductive path.

[0104] Preferably, the column body 011 and the core body 012 are integrally formed by die-casting.

[0105] Preferably, a screw hole 013 is provided in the central concave area of the core body 012. The screw hole 013 is provided with threads to enable quick connection with a matching bolt, which is convenient for simple and efficient connection during battery formation or use, and avoids loosening of the connection of the conductive column and increase in contact resistance caused by poor contact.

[0106] In the prior art, loosening of the connection of the conductive column and increase in contact resistance caused by poor contact will lead to an increase in voltage drop, power loss and insufficient battery charging. Even due to the increase in contact resistance, passing a large current easily causes the temperature of the conductive column to rise sharply, resulting in melting at the connection between the conductive column and the screwing part 02.

[0107] Compared with the prior art, in the present invention, a screw hole is provided in the central concave area of the core body, and the screw hole is provided with threads to enable quick connection with a matching bolt, which is convenient for simple and efficient connection during battery formation or use, and avoids loosening of the connection of the conductive column and increase in contact resistance caused by poor contact.

[0108] Preferably, the diameter of the core body 012 is 10 mm to 30 mm, and the diameter of the column body 011 is 20 mm to 40 mm.

[0109] Preferably, the height of the column body 011 is 30 mm to 50 mm.

[0110] Preferably, the depth of the screw hole 013 is 15 mm to 30 mm, and the diameter is 5 mm to 10 mm.

[0111] Preferably, one or more annular grooves are provided on the outer periphery of the column body 011, and an annular O-ring is provided in a matching manner in the annular groove, so as to achieve a sealed connection between the conductive terminal 01 and the outside.

[0112] Preferably, the width of the annular groove is 2 mm to 5 mm, and the depth is 1 mm to 3 mm.

[0113] On the other hand, the present invention discloses a composite energy storage battery, which uses two of the above busbars as the positive busbar 1a and the negative busbar 1b respectively.

[0114] The composite energy storage battery further includes a plurality of battery cells 2 and electrode plates 3, and the electrode plates 3 and the battery cells 2 are arranged in an alternating stacked manner;

[0115] The battery cell 2 has two opposite side faces with opposite polarities;

[0116] The sides of adjacent battery cells 2 with the same electrode polarity face each other and are connected by the electrode plate 3;

[0117] The end of the positive electrode plate in the electrode plate 3 is connected to the conductive rib 032 of the positive bus bar 1a through the bus bar joint 5;

[0118] The end of the negative electrode plate in the electrode plate 3 is connected to the conductive rib 032 of the negative bus bar 1b through the bus bar joint 5.

[0119] During implementation, the positive electrode plate in the electrode plate 3 collects the positive current or charge of the battery cell 2 and is connected to the outside through the conductive terminal 01 in the positive bus bar 1a; the negative electrode plate in the electrode plate 3 collects the negative current or charge of the battery cell 2 and is connected to the outside through the conductive terminal 01 in the negative bus bar 1b.

[0120] In a feasible implementation manner, as Figure 8a or Figure 8b shown, the conductive rib 032 in the bus bar is arranged parallel to the electrode plate 3, and after the bus bar converges, it converges at the top of the electrode plate 3.

[0121] In another feasible implementation manner, the conductive rib 032 in the bus bar is arranged perpendicular to the electrode plate 3, and after the bus bar converges, it converges at one side of the electrode plate 3.

[0122] On the other hand, the present invention discloses a design method for the bus bar of a composite energy storage battery, including: determining the height H of the longitudinal axis center line of each conductive rib in the bus bar based on the positional relationship of each conductive rib relative to the central axis of the bus bar 1.

[0123] Specifically, a quadratic function of one variable of the positional relationship of each conductive rib relative to the central axis of the bus bar 1 and H is constructed, and the height H of the longitudinal axis center line of each conductive rib is optimized.

[0124] The present invention adjusts the length of the conductive rib according to the position of each conductive rib relative to the converging area, optimizes the transmission path of the current of the conductive rib in the converging area, reduces the loss, makes the output of battery cells in different areas more uniform, and helps to improve the service life and stability of the battery.

[0125] Specifically, the design method for the bus bar of a composite energy storage battery includes:

[0126] S1: Determine the number and spacing of the conductive ribs in the bus bar according to the number and spacing of the electrode plates in the composite energy storage battery;

[0127] S2: Based on the relative position relationship of each conductive rib with respect to the central axis of the busbar, determine the height H of the longitudinal axis centerline of each conductive rib in the busbar;

[0128] S3: Determine the number n of the busbar connectors 5 and the cross-sectional area S0 of the free end;

[0129] S4: Based on the height H of the longitudinal axis centerline of the conductive rib, as well as n and S0, determine the change rate of the cross-sectional area of the conductive rib in the length direction of the conductive rib and the width and cross-sectional area of each region of the conductive rib.

[0130] Specifically, as Figure 6 shown, the conductive rib 032 in the positive busbar described in S1 corresponds one-to-one with the positive electrode plate in the electrode plate 3, and the conductive rib 032 in the negative busbar 1b corresponds one-to-one with the negative electrode plate in the electrode plate 3; at the same time, the conductive rib 032 is connected to the electrode plate 3 through the busbar connector 5. Therefore, the distance between the conductive ribs 032 in the same busbar corresponds to the distance between the electrode plates of the same electrical property in the electrode plate 3. Therefore, the number and distance of the conductive ribs 032 in the busbar correspond to the number and distance of the electrode plates 3.

[0131] Specifically, determining the height H of the longitudinal axis centerline of each conductive rib in the busbar in S2 includes, as Figure 9 shown, taking the straight line where the bottom edge of the conductive rib 032 is located as the abscissa, taking the intersection point of the longitudinal axis centerline of the busbar and the abscissa as the origin, and taking the height H of the conductive rib 032 at its longitudinal axis centerline as the ordinate, to construct the function relationship between H and X: H = aX 2 + bX + c, where a = 0.0025 - 0.005, b = -0.5 - -1, c = 170 - 180.

[0132] It should be noted that, as Figure 2 shown, define the midpoint P of the connection line of the upper left and right vertices of the conductive rib 032 as the highest point of the conductive rib. The distance from the highest point of the conductive rib 032 to the bottom edge of the conductive rib 032 is the height H of the longitudinal axis centerline of the conductive rib; at the same time, define the midpoint of the top of the busbar area as O, and the height difference between the top of the busbar area 031 and the highest point in each conductive rib is H1. The line segment PO shows the equivalent busbar path of the conductive rib 032.

[0133] E>The applicant's research finds that setting the height of the conductive rib according to the above function relationship between H and X has lower power loss and output efficiency compared to setting the same height for each conductive rib. Especially when H1 < 15 mm and the current density of the conductive rib is less than 3 A / mm 2 it is particularly obvious.

[0134] It can be understood that H1 reflects the height of the busbar area 031. The smaller H₁ is, the more helpful it is to reduce the volume of the busbar area 031 and even the busbar, and reduce the raw material consumption. However, it also brings the defects of large current loss and uneven busbar of each conductive rib.

[0135] Compared with the prior art, according to the present invention, the length of the conductive rib is adjusted according to the position of each conductive rib relative to the current collecting area, the transmission path of the current of the conductive rib in the current collecting area is optimized, the loss is reduced, so that the output of the battery cells in different areas is more uniform, which helps to improve the service life and stability of the battery.

[0136] Specifically, determining the number n of the current collecting joints and the cross-sectional area S0 of the free end in S3 includes:

[0137] The number n of the current collecting joints is determined by the processing technology and the self-electric loss of the current collecting joints. A larger number of current collecting joints helps to reduce the self-loss, but brings higher processing difficulties (the current collecting joints are mostly composed of lead wires extended from the power supply electrode plate, so their own diameters limit the number and cannot be increased indefinitely). Therefore, n satisfies that the interval between adjacent current collecting joints is between 4.8 mm and 6.5 mm.

[0138] It should be noted that an excessively large S0 causes an increase in the width and cross-sectional area of the conductive rib, and an excessively small S0 causes a large loss of the conductive rib. S0 satisfies that the current density between the first current collecting joint 5a and the second current collecting joint 5b is between 2.5 A / mm 2 ~3 A / mm 2 between.

[0139] Specifically, S4 includes:

[0140] S401: Determine the number n of the current collecting joints of the conductive rib and the distance between the current collecting joints based on the height H of the longitudinal axis center line of the conductive rib;

[0141] S402: Determine the cross-sectional area Smax of one end of the conductive rib connected to the current collecting area 031;

[0142] S403: Determine the cross-sectional area change rate of the conductive rib based on S0, Smax, the distance L0 between the first current collecting joint 5a and the second current collecting joint 5b, and the length Lmax of the conductive rib (the height H of the longitudinal axis center line of the conductive rib).

[0143] Specifically, S4 includes: the cross-sectional area S at each part of the conductive rib continuously changes to satisfy: S = S0 + (Smax - S0) × (L - L0) / (Lmax - L0);

[0144] Wherein, L is the length of each part of the conductive rib from the free end (the height H of the longitudinal axis center line of the conductive rib), L0 is the distance between the first current collecting joint 5a and the second current collecting joint 5b, Lmax is the length of the conductive rib, S0 is the cross-sectional area of the free end, and can be set according to the design specifications and actual processing conditions; Smax is the cross-sectional area of one end of the conductive rib connected to the current collecting area 031, and Smax satisfies: Smax = S0 × n.

[0145] Specifically, the distance L0 between the first busbar joint 5a and the second busbar joint 5b satisfies: L0 = H2 /

[0146] (n + 1), where H2 is the height of the electrode plate.

[0147] It should be noted that the cross-section of the conductive rib is preferably a regular figure. When the width is fixed, the change rate of the cross-sectional area is equivalent to the change rate of its thickness. Knowing the change rate of the cross-sectional area of the conductive rib and the height H of the vertical axis center line, the conductive rib can be processed.

[0148] Specifically, the busbar grid 03 can be prepared by means such as casting and milling, and is polished to ensure a smooth surface.

[0149] Specifically, the busbar grid 03 can be integrally die-cast with the screw connection part 02 and the conductive terminal 01.

[0150] To better illustrate the present invention, the following embodiments and comparative examples are set:

[0151] Embodiment 1

[0152] This embodiment discloses a busbar for a matching composite energy storage battery and its design method. The number of positive electrode plates of the composite energy storage battery is 19, the number of negative electrode plates is 20, the distance between the same-pole electrode plates is 0.2 mm, and the height H2 of the electrode plate is 117 mm. As Figure 4a shown, the required busbar is designed according to the requirements of the composite energy storage battery:

[0153] S1: Determine that the number of conductive ribs in the positive busbar 1a is 19 and the number of conductive ribs in the negative busbar 1b is 20 according to the number of grid plates, and the distance between the conductive ribs of the two busbars is 0.2 mm;

[0154] S2: According to the function relationship between H and X: H = aX 2 + bX + c, where a = 0.005, b = -1, c = 180, determine the height H of the vertical axis center line of each conductive rib in the busbar;

[0155] S3: Select a lead wire with a diameter of 2.0 mm as the busbar joint for connecting the electrode plate and the conductive rib, determine that the number of busbar joints is 14, select a rectangle with a free-end cross-section of cross-sectional area S0 = 7.6 mm × 0.2 mm, and the distance L0 between the first busbar joint 5a and the second busbar joint 5b = H2 / (n + 1) = 7.8 mm;

[0156] S4: The cross-sectional area Smax of the end of the conductive rib connected to the busbar area 031 = S0 × n = 21.28 mm 2 ; The cross-sectional area S of each part of the conductive rib = S0 + (Smax - S0) × (L - L0) / (Lmax - L0).

[0157] The short side length of the trapezoidal block is 20 mm, the long side length of the trapezoidal block is 40 mm, and the thickness of the trapezoidal block is 20 mm.

[0158] The diameter of the core 012 is 30 mm, and the diameter of the column 011 is 40 mm.

[0159] The height of the column 011 is 50 mm.

[0160] The depth of the screw hole 013 is 30 mm, and the diameter is 10 mm.

[0161] The height H3 from the center of the transverse grid rib 033 to the bottom edge of the busbar grid is 48 mm; the width W of the transverse grid rib 033 is 4 mm.

[0162] The height difference H1 between the top of the busbar area 031 and the highest point of each conductive rib is 12 mm, and the designed current density of the conductive rib is 3.0 A / mm 2 。

[0163] There are 3 annular grooves on the outer periphery of the column 011, and annular O-rings are matched to realize the sealed connection between the conductive terminal and the outside.

[0164] The width of the annular groove is 4 mm, and the depth is 3 mm.

[0165] Select two busbars with the above dimensions as the positive and negative busbars of the composite energy storage battery, and prepare the composite energy storage battery with the battery unit 2 and the electrode plate 3. The electrode plate 3 and the battery unit 2 are arranged in an alternating stacked manner;

[0166] The battery unit 2 has 19 pieces, with two sides of opposite polarities. The adjacent battery units 2 are arranged with the same-polarity sides facing each other and are connected through the electrode plate 3; the battery unit has a designed capacity of 633.33 Ah, 19 positive plates are matched with 20 negative plates, and the capacity provided by each plate is 33.333 Ah.

[0167] The end of the positive plate in the electrode plate 3 is connected to the positive busbar 1a through a busbar joint and a conductive rib;

[0168] The end of the negative plate in the electrode plate 3 is connected to the negative busbar 1b through a busbar joint and a conductive rib.

[0169] Charge the above composite energy storage battery with 250 A and discharge it with 250 A. After 88 cycles of the system, the discharge energy efficiency is 90.1%; the energy density (10 hr) is 95 Wh / L, and the energy storage cost per degree of electricity (battery) is 0.227 yuan

[0170] / kwh, the single total charge capacity is 643.47 Ah; the single discharge capacity is 579.77 Ah, and the charging factor is 102.11%.

[0171] The mechanical strength of the above busbar grid is tested according to the torque standard to be 14.5 N; after the above composite energy storage battery is formed, the maximum deviation of lead oxide in the upper, middle and lower regions of the positive electrode of the battery unit is detected to be 1.43% (the maximum deviation is: the ratio of the difference between the maximum and minimum values of the lead oxide thickness measured in the upper, middle and lower regions to the minimum value, and the maximum deviation below is calculated according to this method).

[0172] Example 2

[0173] This example discloses a busbar for a matching composite energy storage battery and its design method. The number of positive electrode plates of the composite energy storage battery is 15, the number of negative electrode plates is 16, the distance between the same-pole electrode plates is 0.2 mm, and the height H2 of the electrode plate is 117 mm. As Figure 4a shown, the required busbar is designed according to the requirements of the composite energy storage battery:

[0174] S1: Determine that the number of conductive rib strips in the positive busbar 1a is 15 and the number of conductive rib strips in the negative busbar 1b is 16 according to the number of grid plates, and the distance between the conductive rib strips of the two busbars is 0.2 mm;

[0175] S2: As Figure 9 shown, according to the function relationship between H and X: H = aX 2 + bX + c, where a = 0.0025, b = -0.5272, c = 175.71, determine the height H of the longitudinal axis center line of each conductive rib strip in the busbar;

[0176] S3: Select a lead wire with a diameter of 2.0 mm as the busbar joint for connecting the electrode plate and the conductive rib strip, determine that the number of busbar joints is 14, select a rectangle with a free end cross-section of cross-sectional area S0 = 7.6 mm × 0.2 mm, and the distance L0 between the first busbar joint 5a and the second busbar joint 5b = H2 / (n + 1) = 7.8 mm;

[0177] S4: The cross-sectional area Smax of the end of the conductive rib strip connected to the busbar area 031 = S0 × n = 21.28 mm 2 ; the cross-sectional area S of each part of the conductive rib strip = S0 + (Smax - S0) × (L - L0) / (Lmax - L0).

[0178] The short side length of the trapezoidal block is 26 mm, the long side length of the trapezoidal block is 54 mm, and the thickness of the trapezoidal block is 10 mm.

[0179] The diameter of the core body 012 is 20 mm, and the diameter of the column 011 is 26 mm.

[0180] The height of the column 011 is 40 mm.

[0181] The depth of the screw hole 013 is 22 mm, and the diameter is 8 mm.

[0182] The height difference between the top of the current collection area 031 and the highest point of each conductive rib is H1 = 11 mm, and the designed current density of the conductive rib is 2.5 A / mm 2 .

[0183] There are 3 annular grooves on the outer periphery of the column 011, and annular O-rings are provided in the annular grooves, which can realize the sealed connection between the conductive terminal and the outside world.

[0184] The width of the annular groove is 3 mm and the depth is 2 mm.

[0185] The height H3 from the center of the transverse grid rib 033 to the bottom edge of the current collection grid is 67.5 mm; the width W of the transverse grid rib 033 is 6 mm.

[0186] Select two current collection buses with the above dimensions as the positive and negative current collection buses of the composite energy storage battery, and prepare the composite energy storage battery with the battery unit 2 and the electrode plate 3. The electrode plate 3 and the battery unit 2 are arranged in an alternating stacked manner;

[0187] There are 15 battery units 2, which have two sides with opposite polarities. The adjacent battery units 2 are arranged with the same-polarity sides facing each other and are connected by the electrode plate 3; the battery unit has a designed capacity of 500 Ah, 15 positive plates are matched with 16 negative plates, and the capacity provided by each plate is 33.333 Ah.

[0188] The end of the positive plate in the electrode plate 3 is connected to the positive current collection bus 1a through a current collection joint and a conductive rib;

[0189] The end of the negative plate in the electrode plate 3 is connected to the negative current collection bus 1b through a current collection joint and a conductive rib.

[0190] Charge the above composite energy storage battery at 250 A (I2) and discharge it at 250 A (C0.5). After 88 cycles, as Figure 12a shown, the single total charge capacity is 469.539 Ah; the single discharge capacity is 463.92 Ah, the energy density (10 hr) is 60.93 Wh / L, the energy storage cost per degree of electricity (battery) is 0.37 yuan / kwh, the charging factor is 102%; the C0.5 discharge efficiency is 98.8%.

[0191] After 250 cycles, as Figure 12a shown, the single total charge capacity is 468.66 Ah; the single discharge capacity is 461.63 Ah, the energy density (10 hr) is 60.93 Wh / L, the energy storage cost per degree of electricity (battery) is 0.37 yuan / kwh, the charging factor is 102%; the C0.5 discharge efficiency is 98.5%.

[0192] Among them, I2 is the charging of a 500 Ah battery with 250 A; the discharge is represented by the capacity C, and C0.5 is the discharge at a current equal to 500 Ah × 0.5.

[0193] The mechanical strength of the above busbar grille is tested according to the torque standard to be 20 N; after the above composite energy storage battery is formed, the maximum deviation of lead oxide in the upper, middle and lower regions of the positive electrode of the battery unit is detected to be 1.5%.

[0194] Example 3

[0195] This example discloses a busbar matching a composite energy storage battery and its design method. The number of positive electrode plates of the composite energy storage battery is 11, the number of negative electrode plates is 12, the distance between the same-pole electrode plates is 0.2 mm, and the height H2 of the electrode plate is 117 mm. The required busbar is designed according to the requirements of the composite energy storage battery, as Figure 4a shown:

[0196] S1: Determine that the number of conductive ribs in the positive busbar 1a is 11 and the number of conductive ribs in the negative busbar 1b is 12 according to the number of grid plates, and the distance between the conductive ribs of the two busbars is 0.2 mm;

[0197] S2: According to the function relationship between H and X: H = aX 2 + bX + c, where a = 0.0025, b = -0.6, c = 170, determine the height H of the longitudinal axis center line of each conductive rib in the busbar;

[0198] S3: Select a lead wire with a diameter of 2.0 mm as the busbar joint for connecting the electrode plate and the conductive rib, determine that the number of busbar joints is 14, select a rectangle with a free end cross-section of cross-sectional area S0 = 7.6 mm × 0.2 mm, and the distance L0 between the first busbar joint 5a and the second busbar joint 5b = H2 / (n + 1) = 7.8 mm;

[0199] S4: The cross-sectional area Smax of one end of the conductive rib connected to the busbar area 031 = S0 × n = 21.28 mm 2 ; the cross-sectional area S of each part of the conductive rib = S0 + (Smax - S0) × (L - L0) / (Lmax - L0).

[0200] The short side length of the trapezoidal block is 20 mm, the long side length of the trapezoidal block is 40 mm, and the thickness of the trapezoidal block is 5 mm.

[0201] The diameter of the core 012 is 10 mm, and the diameter of the column 011 is 20 mm.

[0202] The height of the column 011 is 30 mm.

[0203] The depth of the screw hole 013 is 15 mm and the diameter is 5 mm.

[0204] The height H3 of the center of the transverse grid rib 033 from the bottom edge of the busbar grille is 72 mm; the width W of the transverse grid rib 033 is 8 mm.

[0205] Two annular grooves are provided on the outer periphery of the column 011, and annular O-rings are matched with the annular grooves to achieve a sealed connection between the conductive terminal and the outside world.

[0206] The annular groove has a width of 2 mm and a depth of 1 mm.

[0207] The height difference between the top of the confluence area 031 and the highest point of each conductive rib is H1 = 13.5mm, and the design current density of the conductive rib is 2.8A / mm 2 .

[0208] Select two busbars of the above size as the positive and negative busbars of the composite energy storage battery, and prepare the composite energy storage battery with the battery unit 2 and the electrode plate 3, and the electrode plate 3 and the battery unit 2 are stacked and arranged at intervals;

[0209] The battery cell 2 is provided with 11 pieces, each having two side surfaces with opposite polarities. The sides of the electrodes of adjacent battery cells 2 with the same polarity are arranged facing each other and connected through the electrode plate 3. The battery cell has a design capacity of 366Ah, with 11 positive plates and 12 negative plates, and each plate provides a capacity of 33.333Ah.

[0210] The end of the positive electrode plate in the electrode plate 3 is connected to the positive electrode bus bar 1a through a bus connector and a conductive rib;

[0211] The end of the negative electrode plate in the electrode plate 3 is connected to the negative electrode bus bar 1b through a bus connector and a conductive rib.

[0212] The composite energy storage battery was charged at 250A and discharged at 250A. After 88 cycles, the total single charge capacity was 344.242Ah; the single discharge capacity was 338.42Ah, and the energy density (10hr) was

[0213] 95.7Wh / L, energy storage cost (battery) 0.228 yuan / kwh, charging factor is 102.9%; discharge efficiency is greater than 98.31%.

[0214] The mechanical strength of the busbar grid was tested according to the torsion standard and found to be 22.3N. After the composite energy storage battery was formed, the maximum deviation of lead oxide in the upper, middle and lower regions of the positive electrode of the battery cell was tested and found to be 1.7%.

[0215] Example 4

[0216] This embodiment discloses a busbar matching a composite energy storage battery and a design method thereof. Compared with embodiment 2, the busbar is not provided with a transverse grid bar 033. Figure 4b As shown, the rest is the same as Example 2.

[0217] Select two of the above-mentioned busbars of the size as the positive and negative busbars of the composite energy storage battery, prepare the composite energy storage battery in the same method as in Example 2, charge the above-mentioned composite energy storage battery at 250 A (I2), discharge it at 250 A (C0.5), and after 88 cycles, as Figure 12b shown, the single total charge capacity is 469.429 Ah; the single discharge capacity is 457.715 Ah, the energy density (10 hr) is 94.8 Wh / L, the storage cost per degree of electricity (battery) is 0.231 yuan / kwh, the charging factor is 102.9%; the C0.5 discharge efficiency is 97.5%.

[0218] Among them, I2 is the battery of 500 Ah charged with 250 A; the discharge is represented by the capacity C, and C0.5 is equal to the discharge at the current of 500 Ah × 0.5.

[0219] Comparison Figure 12a 、 12b It can be seen that compared with Example 4, the discharge efficiency of Example 2 with horizontal grid ribs is significantly greater than that of the scheme without horizontal grid ribs in Example 4 after multiple cycles (for example, the discharge efficiency of Example 2 is greater than 99% after 88 discharges, and the discharge efficiency of Example 4 is 97.5%).

[0220] The mechanical strength of the above busbar grille is tested according to the torsion standard to be 8 N; after the above composite energy storage battery is formed, the maximum deviation of lead oxide in the upper, middle and lower regions of the positive electrode of the battery unit is detected to be 5.3%.

[0221] Compared with the prior art that collects the current of each electrode plate through the tab, the busbar grille of the present invention is provided with multiple independently working conductive rib strips to make the current distribution more uniform, and can collect the current in a larger area on the side area of each electrode plate, fully improving the working efficiency under high power conditions, rather than being limited to the contact area between the tab and the electrode plate in the prior art. Therefore, it can reduce the electrical loss and improve the reliability.

[0222] Example 5

[0223] This example discloses a busbar and its design method for matching a composite energy storage battery. The number of positive electrode plates of the composite energy storage battery is 19, the number of negative electrode plates is 20, the distance between the same-pole electrode plates is 0.2 mm, and the height H2 of the electrode plate is 117 mm. As Figure 4b shown, design the required busbar according to the requirements of the composite energy storage battery:

[0224] S1: Determine that the number of conductive rib strips in the positive busbar 1a is 19 and the number of conductive rib strips in the negative busbar 1b is 20 according to the number of grid plates, and the distance between the conductive rib strips of the two busbars is 0.2 mm;

[0225] S2: According to the function relationship between H and X: H = aX 2+bX + c, where a = 0.005, b = -1, c = 180, to determine the height H of the longitudinal axis center line of each conductive rib in the bus bar;

[0226] S3: Select a 2.0 mm diameter lead wire as the bus bar joint connecting the electrode plate and the conductive rib, determine the number of bus bar joints as 14, select a rectangle with a free end cross-section of cross-sectional area S0 = 7.6 mm × 0.2 mm, and the distance L0 between the first bus bar joint 5a and the second bus bar joint 5b = H2 / (n + 1) = 7.8 mm, where H2 is taken as 117 mm;

[0227] S4: The cross-sectional area Smax at one end where the conductive rib is connected to the bus bar area 031 = S0 × n = 21.28 mm 2 ; The cross-sectional area S at each part of the conductive rib = S0 + (Smax - S0) × (L - L0) / (Lmax - L0).

[0228] The short side length of the trapezoidal block is 20 mm, the long side length of the trapezoidal block is 40 mm, and the thickness of the trapezoidal block is 20 mm.

[0229] The diameter of the core body 012 is 30 mm, and the diameter of the column 011 is 40 mm.

[0230] The height of the column 011 is 50 mm.

[0231] The depth of the screw hole 013 is 30 mm, and the diameter is 10 mm.

[0232] The height difference H1 between the top of the bus bar area 031 and the highest point of each conductive rib is 12 mm, and the designed current density of the conductive rib is 3.0 A / mm 2 .

[0233] There are 3 annular grooves provided on the outer periphery of the column 011, and annular O-rings are provided in the annular grooves to achieve sealed connection between the conductive terminal and the outside.

[0234] The width of the annular groove is 4 mm, and the depth is 3 mm.

[0235] Select two bus bars of the above dimensions as the positive and negative bus bars of the composite energy storage battery, and prepare a composite energy storage battery with the battery unit 2 and the electrode plate 3. The electrode plate 3 and the battery unit 2 are arranged in an alternating stacked manner;

[0236] The battery unit 2 has 19 pieces, with two sides of opposite polarities. The adjacent battery units 2 are arranged with the same-polarity sides facing each other and are connected by the electrode plate 3; The battery unit has a designed capacity of 633.33 Ah, with 19 positive plates and 20 negative plates, and each plate provides a capacity of 33.333 Ah.

[0237] The end of the positive plate in the electrode plate 3 is connected to the positive bus bar 1a through the bus bar joint and the conductive rib;

[0238] The end of the negative electrode plate in the electrode plate 3 is connected to the negative bus bar 1b through a bus bar joint and a conductive rib.

[0239] The above composite energy storage battery is charged at 250 A and discharged at 250 A. After 88 cycles of the system, the discharge energy efficiency is 89%; the energy density (10 hr) is 95 Wh / L, and the energy storage cost per degree of electricity (battery) is 0.229 yuan

[0240] / kwh, the single - total charge capacity is 594.61 Ah; the single - discharge capacity is 579.77 Ah, and the charge factor is 102.11%.

[0241] Example 6

[0242] This example discloses a bus bar for a matching composite energy storage battery and its design method. The number of positive electrode plates in the composite energy storage battery is 11, the number of negative electrode plates is 12, the distance between the same - pole electrode plates is 0.2 mm, and the height H2 of the electrode plate is 117 mm. As Figure 4b shown, the required bus bar is designed according to the requirements of the composite energy storage battery:

[0243] S1: Determine that the number of conductive ribs in the positive bus bar 1a is 11 and the number of conductive ribs in the negative bus bar 1b is 12 according to the number of grid plates. The distance between the conductive ribs of the two bus bars is 0.2 mm;

[0244] S2: According to the function relationship between H and X: H = aX 2 + bX + c, where a = 0.0025, b = - 0.6, c = 170, determine the height H of the longitudinal axis center line of each conductive rib in the bus bar;

[0245] S3: Select a lead wire with a diameter of 2.0 mm as the bus bar joint for connecting the electrode plate and the conductive rib. Determine that the number of bus bar joints is 14. Select a rectangle with a free - end cross - section of cross - sectional area S0 = 7.6 mm×0.2 mm. The distance L0 between the first bus bar joint 5a and the second bus bar joint 5b is L0 = H2 / (n + 1)=7.8 mm, and H2 is taken as 117 mm;

[0246] S4: The cross - sectional area Smax of the end of the conductive rib connected to the bus bar area 031 is Smax = S0×n = 21.28 mm 2 ; the cross - sectional area S of each part of the conductive rib is S = S0+(Smax - S0)×(L - L0) / (Lmax - L0).

[0247] The short side length of the trapezoidal block is 20 mm, the long side length of the trapezoidal block is 40 mm, and the thickness of the trapezoidal block is 5 mm.

[0248] The diameter of the core body 012 is 10 mm, and the diameter of the column body 011 is 20 mm.

[0249] The height of the cylinder 011 is 30 mm.

[0250] The depth of the screw hole 013 is 15 mm and the diameter is 5 mm.

[0251] There are 2 annular grooves on the outer periphery of the cylinder 011, and annular O-rings are arranged in the annular grooves, which can realize the sealed connection between the conductive terminal and the outside.

[0252] The width of the annular groove is 2 mm and the depth is 1 mm.

[0253] The height difference between the top of the busbar area 031 and the highest point of each conductive rib is H1 = 13.5 mm, and the designed current density of the conductive rib is 2.8 A / mm 2 。

[0254] Select two busbars with the above dimensions as the positive and negative busbars of the composite energy storage battery, and prepare the composite energy storage battery with the battery unit 2 and the electrode plate 3. The electrode plate 3 and the battery unit 2 are arranged in an alternating stacked manner;

[0255] There are 11 battery units 2, which have two sides with opposite polarities. The adjacent battery units 2 are arranged with the same-polarity sides facing each other and are connected by the electrode plate 3; the battery unit has a designed capacity of 366 Ah, 11 positive plates are matched with 12 negative plates, and the capacity provided by each plate is 33.333 Ah.

[0256] The end of the positive plate in the electrode plate 3 is connected to the positive busbar 1a through a busbar joint and a conductive rib;

[0257] The end of the negative plate in the electrode plate 3 is connected to the negative busbar 1b through a busbar joint and a conductive rib.

[0258] Charge the above composite energy storage battery at 250 A and discharge it at 250 A. After 88 cycles of the system, the single total charge capacity is 342.513 Ah; the single discharge capacity is 336.13 Ah, and the energy density (10hr)

[0259] is 95.2 Wh / L, the energy storage cost per degree of electricity (battery) is 0.231 yuan / kWh, and the charging factor is 103.1%; the discharge efficiency is greater than 98.21%.

[0260] Comparative Example 1

[0261] Disclose a busbar for matching a composite energy storage battery and its design method, wherein the height H of the longitudinal axis center line of the conductive rib is H = aX 2 + bX + c, where a = 0.002, b = -0.5272, c = 175.71, and the rest is the same as in Example 2.

[0262] Select two of the above-sized busbars as the positive and negative busbars of the composite energy storage battery, prepare the composite energy storage battery in the same method as in Example 2, charge the above composite energy storage battery at 250 A and discharge it at 250 A. After 88 cycles, the single-total charge capacity is 466.322 Ah; the single-discharge capacity is 431.866 Ah, and the charging factor is 102.9%; the C0.5 discharge efficiency is greater than 92.61%.

[0263] Test the mechanical strength of the above busbar grille according to the torque standard to be 20 N; after the above composite energy storage battery is formed, detect that the maximum deviation of lead oxide in the upper, middle and lower regions of the positive electrode of the battery unit is 1.55%.

[0264] Comparative Example 2

[0265] Disclose a busbar matching a composite energy storage battery and its design method, wherein the height H of the conductive rib longitudinal axis center line is H = aX 2 +bX + c, where a = 0.0025, b = -0.4, c = 175.71, and the rest is the same as in Example 2.

[0266] Select two of the above-sized busbars as the positive and negative busbars of the composite energy storage battery, prepare the composite energy storage battery in the same method as in Example 2, charge the above composite energy storage battery at 250 A and discharge it at 250 A. After 88 cycles, the single-total charge capacity is 468.132 Ah; the single-discharge capacity is 432.60 Ah, and the charging factor is 101.9%; the C0.5 discharge efficiency is greater than 92.41%.

[0267] Test the mechanical strength of the above busbar grille according to the torque standard to be 20 N; after the above composite energy storage battery is formed, detect that the maximum deviation of lead oxide in the upper, middle and lower regions of the positive electrode of the battery unit is 1.54%.

[0268] Comparative Example 3

[0269] Disclose a busbar matching a composite energy storage battery, and the height H of the conductive rib is H = aX 2 +bX + c, where a = 0.0025, b = -0.5272, c = 190, and the rest is the same as in Example 2.

[0270] Select two of the above-sized busbars as the positive and negative busbars of the composite energy storage battery, prepare the composite energy storage battery in the same method as in Example 2, charge the above composite energy storage battery at 250 A and discharge it at 250 A. After 88 cycles, the single-total charge capacity is 468.952 Ah; the single-discharge capacity is 428.664 Ah, and the charging factor is 102.5%; the C0.5 discharge efficiency is greater than 91.41%.

[0271] The mechanical strength of the above busbar grille was tested according to the torque standard to be 20 N; after the above composite energy storage battery was formed, the maximum deviation of lead oxide in the upper, middle, and lower regions of the positive electrode of the battery unit was detected to be 1.58%.

[0272] Comparative Example 4

[0273] Disclose a busbar matching a composite energy storage battery. The height of the conductive rib strips is taken as the maximum value of the height of the conductive rib strips in Example 4, and the rest is the same as in Example 4.

[0274] Select two busbars of the above dimensions as the positive and negative busbars of the composite energy storage battery. Prepare the composite energy storage battery according to the same method as in Example 4. Charge the above composite energy storage battery at 250 A and discharge it at 250 A. After 88 cycles, as Figure 12c shown, the total charging capacity is 486.502 Ah, and the retention rate relative to the theoretical design value is 112%; the discharge capacity is 448.172 Ah, and the retention rate relative to the theoretical design value is 110%; the discharge efficiency is 91.88%.

[0275] Comparison Figure 12b 、 12c It can be seen that compared with Comparative Example 4, the discharge efficiency of Example 4 is much greater than that of the scheme with equal-height conductive rib strips in Comparative Example 4 after multiple cycles.

[0276] The mechanical strength of the above busbar grille was tested according to the torque standard to be 8 N; after the above composite energy storage battery was formed, the maximum deviation of lead oxide in the upper, middle, and lower regions of the positive electrode of the battery unit was detected to be 5.33%.

[0277] Comparative Example 5

[0278] Disclose a busbar matching a composite energy storage battery. The thickness / cross-sectional area of the conductive rib strips is taken as the maximum value of the thickness / cross-sectional area of the conductive rib strips in Example 2. Each single conductive rib strip needs to consume nearly twice as much lead material (as can be known from the cube volume formula). The rest is the same as in Example 2.

[0279] Select two busbars of the above dimensions as the positive and negative busbars of the composite energy storage battery. Prepare the composite energy storage battery according to the same method as in Example 2. Charge the above composite energy storage battery at 250 A and discharge it at 250 A. After 88 cycles, the single-time total charging capacity is 470.221 Ah; the single-time discharge capacity is 46,188, and the charging factor is 101.7%; the C0.5 discharge efficiency is 98.93%.

[0280] Comparing Example 2 and Comparative Example 5, the discharge efficiency of Comparative Example 5 has no substantial improvement compared to Example 2, and each single conductive rib strip needs to consume nearly twice as much lead material.

[0281] Compared with the prior art that collects the current of each electrode plate through the tab, the current collecting grid of the present invention is provided with multiple independently operating conductive ribs, which makes the current distribution more uniform. It can collect the current in a larger area on the side area of each electrode plate, fully improving the working efficiency under high-power conditions, rather than being limited to the contact area between the tab and the electrode plate in the prior art. Therefore, it can reduce the electrical loss and improve the reliability.

[0282] The above are only the preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A composite energy storage battery busbar, characterized in that, It includes a conductive terminal, a screw connection part and a busbar grid; The screw connection part is a trapezoidal block. One side of the short side of the trapezoidal block is connected to the bottom of the conductive terminal, and one side of the long side is connected to the busbar grid.

2. The battery bus bar according to claim 1, wherein There are multiple conductive ribs which are arranged in parallel. One ends of the multiple conductive ribs are simultaneously connected to the current collecting area, and the other ends form free ends. Each conductive rib can separately collect the current in each area.

3. The battery bus bar according to claim 2, wherein The lengths of the conductive ribs connected to the current collecting area gradually increase from the center of the current collecting area to both sides.

4. The battery bus bar according to claim 2 or 3, characterized in that, There is a transverse grid rib between the connection end of the conductive rib and the current collecting area and the free end of the conductive rib. The transverse grid rib sequentially connects each conductive rib.

5. The battery bus bar according to claim 1, characterized in that, One side of the short side of the trapezoidal block is provided with an inward concave arc-shaped connection part; the diameter of the arc-shaped connection part matches the outer diameter of the conductive terminal, and the arc-shaped connection part arc-covers the outer wall of the conductive terminal in the connection area with the conductive terminal.

6. The battery busbar according to claim 5, wherein, The trapezoidal block is a trapezoidal block with uniform thickness at the top and bottom surfaces.

7. The battery bus bar according to claim 6, characterized in that, The top and bottom surfaces of the trapezoidal block are perpendicular to the side surface of the busbar grid near the trapezoidal block, and the top and bottom surfaces of the trapezoidal block are perpendicular to the side surface of the connection pole.

8. The battery bus bar according to claim 7, characterized in that, The bottom surface of the conductive terminal is flush with the bottom surface of the trapezoidal block, and the top end surface of the busbar grid is flush with the top surface of the trapezoidal block.

9. The battery busbar according to claim 1, wherein The conductive terminal includes a column body and a core body; The column body is provided with an inward concave chamber, and the core body is nested into the inward concave chamber of the column body. The outer wall of the core body and the inner wall of the column body are connected in a matching manner.

10. A composite energy storage battery, characterized in that, Use the battery busbar according to any one of claims 1-9.

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