Electrical connection system of power battery module and battery pack

Abstract

The invention discloses an electrical connection system of a power battery module and a battery pack, which can be used in the field of power batteries, and the system comprises a cylindrical battery cell array, a high-voltage busbar, a sampling circuit and a battery cell monitoring unit, the high-voltage busbars comprise serial-parallel busbars, main positive output electrode busbars, main negative output electrode busbars and positive and negative electrode bridging busbars, wherein the number of the serial-parallel busbars can be expanded; the cylindrical battery cell array comprises a first battery cell module and a second battery cell module which are arranged along the column direction and both comprise M rows and N columns of cylindrical battery cells; the M rows and N columns of cylindrical battery cells are connected into an M-parallel and N-series structure through N-1 M-parallel series-parallel busbars; and the second end of the first battery cell module is connected with the second end of the second battery cell module through a positive and negative electrode bridging busbar. According to the high-voltage busbar provided by the invention, parallel connection and series connection between the cylindrical battery cells are realized, so that the electrical connection of the power battery is relatively simple and convenient to expand.

Description

Technical Field

[0001] The present application relates to the technical field of power batteries, and particularly to an electrical connection system for a power battery module and a battery pack. Background Art

[0002] With the rapid development of new energy vehicles, as one of the key components, the performance and reliability of power batteries have an important impact on the operation of the whole vehicle.

[0003] In recent years, in addition to traditional square battery cells and blade battery cells, cylindrical battery cells have also been gradually applied to power batteries. Compared with square battery cells and blade battery cells, cylindrical battery cells have certain advantages in terms of energy density and cycle life. However, due to the relatively small size and relatively low capacity of cylindrical battery cells, the number of single cylindrical battery cells in the whole power battery is relatively large, which may reach hundreds or even thousands. And in order to meet the voltage or power requirements of the whole vehicle, a large number of cylindrical battery cells need to be connected depending on complex series-parallel relationships, which brings certain challenges to the design of the electrical connection system.

[0004] Therefore, how to design a relatively simple electrical connection system for a power battery applicable to cylindrical battery cells has become a problem to be solved. Summary of the Invention

[0005] Based on the above problems, the present application provides an electrical connection system for a power battery module and a battery pack based on the electrical connection system, which can relatively simply realize the electrical connection of a power battery using cylindrical battery cells.

[0006] The embodiments of the present application disclose the following technical solutions:

[0007] In a first aspect, the embodiments of the present application provide an electrical connection system for a power battery module, the system includes: a cylindrical battery cell array, a high-voltage busbar, a sampling circuit, and a battery cell monitoring unit;

[0008] The high-voltage busbar includes an expandable series-parallel busbar, a main positive output terminal busbar, a main negative output terminal busbar, and a positive-negative cross-connection busbar;

[0009] The cylindrical battery cell array includes a first battery cell module and a second battery cell module arranged along the column direction. Both the first battery cell module and the second battery cell module include M rows and N columns of cylindrical battery cells; the M rows and N columns of cylindrical battery cells are connected into an M-parallel and N-series structure through N - 1 M-parallel series-parallel busbars; where M and N are positive integers;

[0010] The first end of the first battery cell module is connected to the main positive output terminal busbar; the first end of the second battery cell module is connected to the main negative output terminal busbar; the second ends of the first battery cell module and the second battery cell module are connected through the positive and negative cross-connecting busbars;

[0011] The sampling terminal of the sampling circuit is electrically connected to the pole post of the cylindrical battery cell and the high-voltage busbar; the sampling circuit is electrically connected to the battery cell monitoring unit.

[0012] Optionally, the series-parallel connection busbar includes a positive end and a negative end;

[0013] The positive end is strip-shaped, and the welding part between the positive end and the positive electrode of the cylindrical battery cell is a semi-circular structure, and the diameter of the semi-circle is less than or equal to the diameter of the positive electrode of the cylindrical battery cell;

[0014] The negative end is arc-shaped, the inner circumference of the arc is less than or equal to the arc length of a semi-circle with a diameter equal to the inner diameter of the arc, the outer circumference of the arc is less than or equal to the arc length of a semi-circle with a diameter equal to the outer diameter of the arc, the inner diameter of the arc is greater than the diameter of the positive electrode of the cylindrical battery cell, and the outer diameter of the arc is less than or equal to the diameter of the cylindrical battery cell;

[0015] The height difference between the positive end and the negative end is equal to the height difference between the positive and negative electrodes of the cylindrical battery cell;

[0016] The positive end is welded to the positive electrode of the cylindrical battery cell; the negative end is welded to the negative electrode of the cylindrical battery cell.

[0017] Optionally, the upper surface and the lower surface of the high-voltage busbar are covered with an insulating film, and the covered area of the insulating film does not include the connection area between the high-voltage busbar and the cylindrical battery cell.

[0018] Optionally, the insulating film includes four positioning bosses.

[0019] Optionally, the sampling circuit includes positioning holes corresponding to the positioning bosses.

[0020] Optionally, the sampling circuit includes a main positive side circuit and a main negative side circuit;

[0021] The sampling terminals of the main positive side circuit and the main negative side circuit include nickel sheet terminals and thermistors; the nickel sheet terminals are welded to the series-parallel connection busbar and the positive and negative cross-connecting busbars; the thermistors are bonded to the pole post of the cylindrical battery cell, the main positive output terminal busbar and the main negative output terminal busbar;

[0022] The main positive side circuit is connected to the pole post of the cylindrical battery cell corresponding to the first battery cell module and the high-voltage busbar;

[0023] The main negative-side circuit is connected to the pole posts of the cylindrical cells corresponding to the second cell module and the high-voltage busbar.

[0024] Optionally, the cell monitoring unit includes a connector; the cell monitoring unit is electrically connected to the sampling circuit through the connector.

[0025] Optionally, the system further includes: a low-voltage harness accessory and a battery management unit;

[0026] The low-voltage harness accessory is used to connect the battery management unit in series with a plurality of cell monitoring units.

[0027] Optionally, the connecting lines of the axis projection points of three adjacent cylindrical cells located in adjacent rows in the cylindrical cell array form an isosceles triangle or an equilateral triangle.

[0028] In a second aspect, an embodiment of the present application provides a battery pack, which applies the electrical connection system of the power battery module described in any one of the first aspects.

[0029] Compared with the prior art, the present application has the following beneficial effects:

[0030] An embodiment of the present application provides an electrical connection system for a power battery module, which includes: a cylindrical cell array, a high-voltage busbar, a sampling circuit, and a cell monitoring unit; the high-voltage busbar includes an expandable parallel-series busbar, a main positive output-pole busbar, a main negative output-pole busbar, and a positive-negative cross-connecting busbar; the cylindrical cell array includes a first cell module and a second cell module arranged in a column direction, and both the first cell module and the second cell module include M rows and N columns of cylindrical cells; the M rows and N columns of cylindrical cells are connected into an M-parallel and N-series structure through N-1 M-parallel parallel-series busbars; wherein, M and N are positive integers; the first end of the first cell module is connected to the main positive output-pole busbar; the first end of the second cell module is connected to the main negative output-pole busbar; the second ends of the first cell module and the second cell module are connected through the positive-negative cross-connecting busbar; the sampling end of the sampling circuit is electrically connected to the pole posts of the cylindrical cells and the high-voltage busbar; the sampling circuit is electrically connected to the cell monitoring unit. Thus, the parallel and series connections between the cylindrical cells are realized through the high-voltage busbar including the expandable parallel-series busbar, the main positive output-pole busbar, the main negative output-pole busbar, and the positive-negative cross-connecting busbar, and the main positive output-pole busbar and the main negative output-pole busbar are located on the same side of the cell module, which can reduce the number of cross-connecting copper bars required between the cell modules, reduce weight and cost, and save the layout space required for the cross-connecting output poles, thereby making the electrical connection of the power battery relatively simple. Description of the Drawings

[0031] To more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0032] Figure 1 Structural diagram of an electrical connection system for a power battery module provided by an embodiment of the present application;

[0033] Figure 2 Structural diagram of a high-voltage busbar provided by an embodiment of the present application;

[0034] Figure 3 Schematic diagram of the expansion of the number of parallel connections of a series-parallel busbar provided by an embodiment of the present application;

[0035] Figure 4 Schematic diagram of the principle of an electrical connection system for a power battery module provided by an embodiment of the present application;

[0036] Figure 5 Structural diagram of a series-parallel busbar provided by an embodiment of the present application;

[0037] Figure 6 Structural diagram of a positive-negative cross-connecting busbar provided by an embodiment of the present application;

[0038] Figure 7 Partially enlarged view of the positioning characteristics of a high-voltage busbar and a sampling circuit provided by an embodiment of the present application. Detailed implementation manners

[0039] An electrical connection system for a power battery module and a battery pack provided by the present application can be used in the field of power batteries. The above is only an example and does not limit the application fields of an electrical connection system for a power battery module and a battery pack provided by the present invention.

[0040] The terms "first", "second", "third", and "fourth" in the description, claims, and drawings of the present application are used to distinguish different objects, rather than to limit a specific order.

[0041] In the embodiments of the present application, words such as "as an example" or "for example" are used to represent examples, illustrations, or explanations. Any embodiment or design solution described as "as an example" or "for example" in the embodiments of the present application should not be interpreted as being more preferred or having more advantages than other embodiments or design solutions. Exactly, the use of words such as "as an example" or "for example" is intended to present relevant concepts in a specific manner.

[0042] The terms used in the embodiments section of this application are only for explaining the specific embodiments of this application and are not intended to limit this application.

[0043] To enable those skilled in the art to better understand the solution of this application, the following will clearly and completely describe the technical solutions in the embodiments of this application with reference to the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are only a part of the embodiments of this application, rather than all the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of this application.

[0044] See Figure 1 , which is a structural diagram of the electrical connection system of a power battery module provided by an embodiment of this application. The system includes: a cylindrical battery cell array 100, a high-voltage busbar 200, a sampling circuit 300, and a battery cell monitoring unit 400.

[0045] Specifically, see Figure 2 , which is a structural diagram of a high-voltage busbar provided by an embodiment of this application. The high-voltage busbar 200 may include a series-parallel busbar 210 with an expandable number, a main positive output pole busbar 230, a main negative output pole busbar 240, and a positive-negative cross-connection busbar 220.

[0046] Optionally, the material of the high-voltage busbar can be nickel-plated copper or nickel-plated aluminum. To fit the shape of the high-voltage busbar and achieve a better welding effect, the welding track of the high-voltage busbar with the positive end of the cylindrical battery cell can be a circle or a ring; the welding track with the negative end of the cylindrical battery cell can be a spiral or an arc.

[0047] Optionally, the upper and lower surfaces of the high-voltage busbar are covered with an insulating film 250, and the covered area of the insulating film 250 does not include the connection area between the high-voltage busbar and the cylindrical battery cell to avoid the insulating film 250 affecting the connection effect of the circuit in the system. The insulating film 250 can be covered on the upper and lower surfaces of the high-voltage busbar by bonding or hot pressing, etc., so as to integrate all the busbar monomers that make up the high-voltage busbar together, reduce the assembly difficulty of the battery factory, and improve the production efficiency of the power battery.

[0048] Optionally, four positioning bosses 260 can be set at the four corner positions of the insulating film 250. For example, they can be set at a position 1-2 times the diameter of the cylindrical battery cell away from the edge position of the high-voltage busbar; the positioning bosses 260 have positioning pin features.

[0049] Exemplarily, one end of the main positive output busbar 230 is connected to the main positive high-voltage copper bar, and the other end is welded to the positive electrodes of a plurality of cylindrical battery cells. The number of cylindrical battery cells connected is the parallel number M of the battery cell module; one end of the main negative output busbar 240 is connected to the main negative high-voltage copper bar, and the other end is welded to the negative electrodes of a plurality of cylindrical battery cells. The number of cylindrical battery cells connected is also the parallel number M of the battery cell module.

[0050] See Figure 3 , which is a schematic diagram of the parallel number expansion of a series-parallel busbar provided in an embodiment of the present application. A plurality of sub-busbars with positive and negative extreme structural features in one parallel (1P) can be movably connected to form a series-parallel busbar with the required parallel number. For example, when two 1P sub-busbars are connected, a 2-parallel (2P) series-parallel busbar can be formed; when three 1P sub-busbars are connected, a 3-parallel (3P) series-parallel busbar can be formed, etc. The number of sub-busbars included in the series-parallel busbar, that is, the number of negative extreme arcs or positive extreme semi-circles included, is equal to the parallel number M of the battery cell module. By expanding the positive and negative extreme structural features of the series-parallel busbar, the free expansion of the parallel number of cylindrical battery cells required in the system can be realized.

[0051] The cylindrical battery cell array 100 includes a first battery cell module and a second battery cell module arranged in the column direction. Among them, both the first battery cell module and the second battery cell module include M rows and N columns of cylindrical battery cells 110. The M rows and N columns of cylindrical battery cells are connected into an M-parallel and N-series structure through N - 1 series-parallel busbars with M parallel; where M and N are positive integers. For example, the cylindrical battery cell array 100 includes a total of 8 rows and 18 columns, a total of 144 cylindrical battery cells. Then each battery cell module includes 4 rows and 18 columns of cylindrical battery cells, that is, M is 4 and N is 18; 4 battery cells in each column are connected in parallel through a series-parallel busbar, and 18 columns of battery cells are connected in series between columns through 17 series-parallel busbars. By adjusting the number of series-parallel busbars arranged in the row direction of the battery cell module, the free expansion of the number of series of cylindrical battery cells required in the system can be realized.

[0052] Optionally, the connecting line of the axis projection points of three adjacent cylindrical battery cells located in adjacent rows in the cylindrical battery cell array 100 is an isosceles triangle or an equilateral triangle.

[0053] Optionally, the distance between adjacent cylindrical battery cells in the cylindrical battery cell array 100 is 4 - 5 millimeters.

[0054] See Figure 4, This figure is a schematic diagram of the principle of an electrical connection system for a power battery module provided by an embodiment of the present application. In this figure, four cylindrical battery cells, namely cell1, cell2, cell3, and cell4, are connected in parallel with each other as a string. Series1, series2, series3, ……, series i are connected in series to form i strings, thus forming a first battery cell module with a 4-parallel and i-series structure; the number of seriesi, ……, series n is also i, and after being connected in series, a second battery cell module with a 4-parallel and i-series structure is formed; the first end of the first battery cell module is the main positive output terminal, and the first end of the second battery cell module is the main negative output terminal. The sampling circuit FPC on the main positive output terminal side and the sampling circuit FPC on the main negative output terminal side are connected to the cell monitor unit (CMU).

[0055] The first end of the first battery cell module is connected to the main positive output terminal busbar 230; the first end of the second battery cell module is connected to the main negative output terminal busbar 240; the second ends of the first battery cell module and the second battery cell module are connected through the positive and negative cross-connection busbar 220.

[0056] Thus, the main positive output terminal and the main negative output terminal of the battery cell module can be located on the same side of the battery cell module, thereby reducing the number of cross-connection copper bars required between battery cell modules, reducing weight and cost; in addition, using the positive and negative cross-connection busbar 220 to replace the individual cross-connection copper bars can also save the layout space required for the cross-connection output terminals, making the overall integration of the high-voltage busbars higher.

[0057] The sampling terminals of the sampling circuit are electrically connected to the electrode posts of the cylindrical battery cells and the high-voltage busbars; the sampling circuit is electrically connected to the cell monitor unit.

[0058] Thus, the electrical connection system for the power battery module provided by the embodiment of the present application can be applied to power batteries using cylindrical battery cells. In this system, the parallel and series connections between the cylindrical battery cells are realized through high-voltage busbars including expandable parallel-series busbars, main positive output terminal busbars, main negative output terminal busbars, and positive and negative cross-connection busbars. Moreover, the main positive output terminal busbar and the main negative output terminal busbar are located on the same side of the battery cell module, which can reduce the number of cross-connection copper bars required between battery cell modules, reduce weight and cost, save the layout space required for the cross-connection output terminals, and relatively simply realize the electrical connection of power batteries using cylindrical battery cells. In addition, since the number of parallel connections of the parallel-series busbars is expandable and the number of parallel-series busbars can be flexibly adjusted in the row direction of the battery cell module, the system provided by the embodiment of the present application can realize the free expansion of the number of parallel and series connections of the battery cell module, and can better meet the complex parallel and series relationships between a large number of cylindrical battery cells.

[0059] See Figure 5, This figure is a structural diagram of a series-parallel busbar provided by an embodiment of the present application. The series-parallel busbar 210 includes a positive terminal and a negative terminal.

[0060] Specifically, the positive terminal can be strip-shaped. The welding part between the positive terminal and the positive electrode of the cylindrical battery cell is a semi-circular structure, and the diameter of the semi-circle is less than or equal to the diameter of the positive electrode of the cylindrical battery cell. A through hole 211 can be provided in the semi-circular structure area of the positive terminal to facilitate visual positioning and identification during the installation process of the system.

[0061] The negative terminal can be arc-shaped. The inner circumference of the arc is less than or equal to the arc length of a semi-circle with a diameter equal to the inner diameter of the arc, and the outer circumference of the arc is less than or equal to the arc length of a semi-circle with a diameter equal to the outer diameter of the arc. The inner diameter of the arc is greater than the diameter of the positive electrode of the cylindrical battery cell, and the outer diameter of the arc is less than or equal to the diameter of the cylindrical battery cell.

[0062] Optionally, there is a height difference Δ equal to the height difference between the positive and negative electrodes of the cylindrical battery cell between the positive terminal and the negative terminal of the series-parallel busbar 210, and the positive terminal is higher than the negative terminal. The positive terminal is welded to the positive electrode of the cylindrical battery cell in series k, and the negative terminal is welded to the negative electrode of the cylindrical battery cell in series k + 1, playing a bridging role between series.

[0063] See Figure 6 , This figure is a structural diagram of a positive-negative cross-connecting busbar provided by an embodiment of the present application. The positive-negative cross-connecting busbar 220 is arranged at one end far from the output pole of the battery cell module, and includes a positive terminal and a negative terminal with the same number as the parallel number of the module. The structures of its positive terminal and negative terminal are the same as those of the positive terminal and negative terminal of the series-parallel busbar, so as to connect the first battery cell module and the second battery cell module, thus replacing the conventional cross-connecting copper bar, saving the output pole space for the installation of the matching copper bar, and improving the integration of the system.

[0064] Optionally, in some other embodiments provided by the present application, the sampling circuit includes a main positive side circuit and a main negative side circuit. Specifically, the sampling terminals of the main positive side circuit and the main negative side circuit include nickel sheet terminals and thermistors; the nickel sheet terminals are welded to the series-parallel busbar and the positive-negative cross-connecting busbar; the thermistors are bonded to the pole posts of the cylindrical battery cells, the main positive output pole busbar, and the main negative output pole busbar.

[0065] Among them, the number of nickel sheet terminals corresponds to the number of strings of the battery cell module, that is, N. Each nickel sheet terminal is welded to a series-parallel busbar for voltage sampling; the thermistor NTC is bonded to the pole posts of the corresponding cylindrical battery cells and the output poles for temperature sampling of the battery cells and the positive and negative busbars. Preferably, the thermistor NTC is bonded to the positive pole post of the cylindrical battery cell to obtain a battery cell temperature closer to the actual situation.

[0066] The main positive side circuit is connected to the electrode posts of the cylindrical battery cells corresponding to the first battery cell module and the high-voltage busbar; the main negative side circuit is connected to the electrode posts of the cylindrical battery cells corresponding to the second battery cell module and the high-voltage busbar.

[0067] See Figure 7 , which is a partially enlarged view of the positioning features of a high-voltage busbar and a sampling circuit provided by an embodiment of the present application. The sampling circuit is provided with positioning holes 310 at positions corresponding to the positioning bosses. After the high-voltage busbar is welded, the sampling circuit can perform feature matching between its own positioning holes 310 and the positioning bosses 260 to achieve positioning.

[0068] Optionally, the sampling circuit is provided with sampling connectors on the side close to the module output pole. For example, the main positive side circuit is provided with a first sampling connector at a position close to the main positive output pole, and the main negative side circuit is provided with a second sampling connector at a position close to the main negative output pole.

[0069] Optionally, connectors for pairing with the sampling circuit are provided on both sides of the cell monitoring unit CMU400 to achieve sampling of voltage and temperature.

[0070] In some other embodiments provided by the present application, the electrical connection system of the power battery further includes a low-voltage wire harness accessory and a battery management unit. Among them, both ends of the low-voltage wire harness accessory 500 have connectors. The two ends of the low-voltage wire harness accessory 500 are respectively plugged into two adjacent cell monitoring units CMU, or one end is plugged into the cell monitoring unit CMU and the other end is plugged into the whole-pack battery management unit (Battery Management System, BMU), so as to realize signal communication.

[0071] In addition, the present application also provides a battery pack applying the above electrical connection system of the power battery.

[0072] It should be noted that the various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other, and the key points of each embodiment are the differences from other embodiments. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. Those of ordinary skill in the art can understand and implement it without creative labor.

[0073] The above is only a specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present application should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. An electrical connection system for a power battery, characterized in that: The system comprises: a cylindrical battery cell array, a high voltage bus bar, a sampling circuit and a battery cell monitoring unit; The high-voltage busbars include a series-parallel busbar with expandable parallel numbers, a main positive output busbar, a main negative output busbar, and a positive and negative crossover busbar; The cylindrical battery cell array comprises a first battery cell module and a second battery cell module arranged in a column direction, and the first battery cell module and the second battery cell module both comprise cylindrical battery cells in M ​​rows and N columns; The cylindrical cells in M ​​rows and N columns are connected to form an M-parallel and N-series structure through N-1 M-parallel series-parallel busbars; wherein M and N are positive integers; The first end of the first battery cell module is connected to the main positive output busbar; the first end of the second battery cell module is connected to the main negative output busbar; the second end of the first battery cell module and the second end of the second battery cell module are connected via the positive and negative jumper busbar; The sampling end of the sampling circuit is electrically connected to the pole of the cylindrical battery cell and the high-voltage bus; the sampling circuit is electrically connected to the battery cell monitoring unit.

2. The system according to claim 1, characterized in that The series-parallel busbar includes a positive terminal and a negative terminal; The positive terminal is in the shape of a long strip, and the welding point between the positive terminal and the positive electrode of the cylindrical battery cell is a semicircular structure, and the diameter of the semicircle is less than or equal to the diameter of the positive electrode of the cylindrical battery cell; The negative terminal is in the shape of an arc, the inner circumference of the arc is less than or equal to the arc length of a semicircle whose diameter is the inner diameter of the arc, the outer circumference of the arc is less than or equal to the arc length of a semicircle whose diameter is the outer diameter of the arc, the inner diameter of the arc is greater than the positive electrode diameter of the cylindrical battery cell, and the outer diameter of the arc is less than or equal to the diameter of the cylindrical battery cell; The height difference between the positive terminal and the negative terminal is equal to the height difference between the positive and negative electrodes of the cylindrical battery cell; The positive terminal is welded to the positive electrode of the cylindrical battery cell; the negative terminal is welded to the negative electrode of the cylindrical battery cell.

3. The system according to claim 1, characterized in that The upper surface and the lower surface of the high-voltage busbar are covered with an insulating film, and the covering area of ​​the insulating film does not include the connection area between the high-voltage busbar and the cylindrical battery cell.

4. The system according to claim 3, wherein the device comprises: The insulating film includes four positioning bosses.

5. The system according to claim 4, characterized in that The sampling circuit comprises a positioning hole corresponding to the positioning boss.

6. The system according to claim 1, characterized in that The sampling circuit comprises a main positive side circuit and a main negative side circuit; The sampling ends of the main positive side circuit and the main negative side circuit include nickel sheet terminals and thermistors; the nickel sheet terminals are welded to the series-parallel busbars and the positive-negative crossover busbars; the thermistors are bonded to the poles of the cylindrical cells, the main positive output busbars, and the main negative output busbars; The main positive side circuit is connected to the poles of the cylindrical cells corresponding to the first cell module and the high-voltage busbar; The main negative side circuit is connected to the poles of the cylindrical cells corresponding to the second cell module and the high-voltage bus.

7. The system according to claim 1, characterized in that The battery cell monitoring unit includes a connector; the battery cell monitoring unit is electrically connected to the sampling circuit through the connector.

8. The system according to claim 1, characterized in that The system also includes: a low voltage wiring harness accessory and a battery management unit; The low-voltage wiring harness accessory is used to connect the battery management unit and multiple battery cell monitoring units in series.

9. The system according to claim 1, characterized in that The line connecting the axis projection points of three adjacent cylindrical battery cells located in two adjacent rows in the cylindrical battery cell array forms an isosceles triangle or an equilateral triangle.

10. A battery pack, characterized in that: An electrical connection system for a power battery according to any one of claims 1 to 9.

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