Connecting unit, busbar, and battery module

Abstract

Disclosed in the present application are a connecting unit, a busbar, and a battery module. The connecting unit is configured to connect battery cells, the battery cells comprising at least a first battery cell and a second battery cell. The connecting unit comprises: a first positive electrode connecting portion, which is configured to be detachably connected to a positive electrode of the first battery cell and is electrically connected to the positive electrode of the first battery cell; and a first negative electrode connecting portion, which is configured to be detachably connected to a negative electrode of the second battery cell and is electrically connected to the negative electrode of the second battery cell, wherein the first negative electrode connecting portion is connected to the first positive electrode connecting portion.

Description

Connection units, busbars, and battery modules

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on December 31, 2023, with application number 202311874131.8. The entire contents of the above application are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of battery technology, and in particular to a connection unit, a bus bar, and a battery module. Background Art

[0003] Power batteries often have multiple cells, and busbars are needed to electrically connect the cells. To achieve this, the busbars are typically welded to the cells, for example, by welding the busbars to the cell terminals. SUMMARY OF THE INVENTION

[0004] However, the welding process is complex and inefficient, and during the welding process of the busbar and the battery cell pole, it is easy to cause poor welding between the busbar and the battery cell, affecting the yield.

[0005] The embodiments of the present application provide a connection unit, a busbar, and a battery module, which realize a detachable connection between the connection unit and the battery cell. Compared with the related art method of welding the busbar to the battery cell pole, the connection process is simplified and the production efficiency and yield are improved.

[0006] In a first aspect, the present application provides a connection unit configured to connect battery cells, the battery cells including at least a first battery cell and a second battery cell, the connection unit including: a first positive electrode connection portion, configured to be detachably connected to the positive electrode of the first battery cell and electrically connected to the positive electrode of the first battery cell, a first negative electrode connection portion, configured to be detachably connected to the negative electrode of the second battery cell and electrically connected to the negative electrode of the second battery cell; wherein the first negative electrode connection portion is connected to the first positive electrode connection portion to connect the first battery cell and the second battery cell in series.

[0007] In the second aspect, the present application provides a busbar, including a connecting unit as described above, wherein the first positive pole connecting portion and the first negative pole connecting portion in each connecting unit are arranged along a first direction, and multiple connecting units are arranged along the first direction, and two adjacent connecting units arranged along the first direction are defined as a first connecting unit and a second connecting unit, respectively. The first negative pole connecting portion of the first connecting unit is sleeved on the negative pole of the first battery cell, the first positive pole connecting portion of the second connecting unit is sleeved on the positive pole of the first battery cell, and the first negative pole connecting portion of the second connecting unit is sleeved on the negative pole of the second battery cell.

[0008] In a third aspect, the present application provides a battery module comprising a plurality of battery cells; and the above-mentioned bus bar, which is configured to connect the plurality of battery cells. Beneficial effects

[0009] The beneficial effects of the present application are as follows: the connection unit provided in the present application can be detachably connected to the positive electrode of the first battery cell through the first positive electrode connection part, and the first negative electrode connection part can be detachably connected to the negative electrode of the second battery cell, thereby realizing the electrical connection between the connection unit and the battery cell, and realizing the detachable connection of the battery cell. Compared with the related art of welding the busbar to the battery cell pole, the connection process is simplified, and the production efficiency and yield are improved.

[0010] The busbar provided in this application utilizes the aforementioned connection units. The first positive electrode connection portion and the first negative electrode connection portion of each connection unit are arranged along a first direction. Multiple connection units are arranged along the first direction, and two adjacent connection units arranged along the first direction are defined as a first connection unit and a second connection unit. The first negative electrode connection portion of the first connection unit is sleeved onto the negative electrode of the first battery cell, the first positive electrode connection portion of the second connection unit is sleeved onto the positive electrode of the first battery cell, and the first negative electrode connection portion of the second connection unit is sleeved onto the negative electrode of the second battery cell. This effectively improves production efficiency and yield.

[0011] The battery module provided in the present application includes a plurality of battery cells and employs the aforementioned busbar, which is configured to connect the plurality of battery cells, thereby effectively improving the production efficiency and yield of the battery module. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] FIG1 is a schematic structural diagram of a battery module provided in an embodiment of the present application;

[0013] FIG2 is a top view of FIG1 ;

[0014] FIG3 is a schematic diagram of a portion of the structure in FIG1 ;

[0015] FIG4 is a top view of FIG3;

[0016] FIG5 is a schematic structural diagram of a busbar provided in an embodiment of the present application;

[0017] FIG6 is a partial enlarged view of point A in FIG5 ;

[0018] FIG7 is a partial enlarged view of point B in FIG5;

[0019] FIG8 is a set of experimental data of the connection unit in one embodiment of the present application.

[0020] Description of reference numerals:

[0021] Battery cell 100, first battery cell 11, second battery cell 13, third battery cell 14, positive electrode 111 of the first battery cell 11, negative electrode 133 of the second battery cell 13, bus 200, third connecting unit 205, parallel part 207, battery module 300, positive bus 303, second positive electrode connecting part 3031, negative bus 305, second negative electrode connecting part 3051, FPC 302, first positive electrode connecting part 21, first surrounding part 210, first spring piece 23, first negative electrode connecting part 31, second surrounding part 310, second spring piece 33, first connecting unit 201, second connecting unit 203, connecting part 51, first end 511, second end 513. Modes for Carrying Out the Invention

[0022] In the description of this application, unless otherwise specified or limited, the terms "connected," "connect," and "fixed" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and can refer to internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on the specific circumstances.

[0023] In this application, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Moreover, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0024] In the description of this embodiment, the terms "upper," "lower," "right," and other orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely for ease of description and simplified operation. They do not indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, the terms "first" and "second" are provided solely for descriptive purposes and do not have any special meanings.

[0025] In the connection design of the power battery system in the related art, a busbar is often used to achieve electrical connection between the battery cells, wherein the busbar usually needs to be welded to the battery cell pole. However, in the welding process of the busbar and the battery cell pole, the welding parameters of each battery cell need to undergo a repeated verification process before production. The verification process consumes huge human resources, material resources, equipment resources, and a long time cost, etc. In addition, the welding equipment requires a huge capital investment when the production line is built, and most of the welding tooling is not compatible and needs to be customized and developed, which will also consume a lot of manpower, material and financial resources. In addition, cold welds will also occur during the welding process. Since there is no accurate welding quality detection method in the industry, cold welds cannot be effectively detected. This will cause the battery system to experience long-term driving vibration after installation, posing a safety hazard.

[0026] The battery module provided in the embodiment of the present application may include battery cells and a busbar, and the busbar may include multiple connection units. The connection unit may be configured to connect battery cells, wherein the battery cells include at least a first battery cell and a second battery cell, and the connection unit includes: a first positive electrode connection portion, configured to be detachably connected to the positive electrode of the first battery cell and electrically connected to the positive electrode of the first battery cell; a first negative electrode connection portion, configured to be detachably connected to the negative electrode of the second battery cell and electrically connected to the negative electrode of the second battery cell; the first negative electrode connection portion is connected to the first positive electrode connection portion to connect the first battery cell and the second battery cell in series.

[0027] In the embodiment of the present application, the first positive electrode connecting part and the positive electrode of the first battery cell are detachable, and the first negative electrode connecting part and the negative electrode of the second battery cell are detachable, thereby realizing detachable connection between the connection unit and the battery cell, and between the battery cells. Compared with the related art method of welding the bus bar to the battery cell pole, the connection process is simplified and the production efficiency and yield are improved.

[0028] In some specific embodiments, the first positive electrode connector can be mounted on the positive electrode of the first battery cell, and the first negative electrode connector can be mounted on the negative electrode of the second battery cell. By mounting the first positive electrode connector on the positive electrode of the first battery cell and the first negative electrode connector on the negative electrode of the second battery cell, the contact area between the first positive electrode connector and the positive electrode of the first battery cell can be increased, and the contact area between the first negative electrode connector and the negative electrode of the second battery cell can also be increased, thereby avoiding poor contact and improving production efficiency and yield.

[0029] As shown in Figure 1, Figure 1 is a schematic structural diagram of a battery module 300 provided in an embodiment of the present application. The battery module 300 provided in an embodiment of the present application includes a battery cell 100 and a bus bar 200, and the bus bar 200 includes a plurality of connection units. The connection unit is configured to connect the battery cell 100, and the battery cell includes at least a first battery cell 11 and a second battery cell 13. The connection unit includes: a first positive electrode connection portion 21, configured to connect the positive electrode 111 of the first battery cell 11, and electrically connected to the positive electrode 111 of the first battery cell 11, a first negative electrode connection portion 31, configured to connect the negative electrode 133 of the second battery cell 13, and electrically connected to the negative electrode 133 of the second battery cell 13; and wherein the first negative electrode connection portion 31 is connected to the first positive electrode connection portion 21 to connect the first battery cell 11 and the second battery cell 13 in series.

[0030] In an embodiment of the present application, the connecting unit is configured to connect the battery cells 100, and there are multiple battery cells 100, each of which has a positive electrode and a negative electrode. For the convenience of distinction, in an embodiment of the present application, as shown in Figure 3, Figure 3 is a partial structure in Figure 1; the multiple battery cells may specifically include a first battery cell 11 and a second battery cell 13, and the first battery cell 11 and the second battery cell 13 both have a positive electrode and a negative electrode. The connecting unit is configured to connect the first battery cell 11 and the second battery cell 13 in series. Specifically, the connecting unit may include a first positive electrode connecting portion 21 and a first negative electrode connecting portion 31. The first positive electrode connecting portion 21 can be configured to be mounted on the positive electrode 111 of the first battery cell 11 and electrically connected to the positive electrode 111 of the first battery cell 11. The first negative electrode connecting portion 31 can be configured to be mounted on the negative electrode 133 of the second battery cell 13 and electrically connected to the negative electrode 133 of the second battery cell 13. The first negative electrode connecting portion 31 is connected to the first positive electrode connecting portion 21 to connect the first battery cell 11 and the second battery cell 13 in series.

[0031] In the embodiment of the present application, the first positive electrode connecting portion 21 is mounted on the positive electrode 111 of the first battery cell 11, and the first negative electrode connecting portion 31 is mounted on the negative electrode 133 of the second battery cell 13, so as to realize the series connection of the first battery cell 11 and the second battery cell 13. Compared with the method of welding the busbar to the battery cell pole in the related art, the embodiment of the present application can not only reduce the investment in human and material resources for welding equipment and welding debugging and verification, so that the production efficiency of the battery module is rapidly improved (it takes about 10 seconds to weld a battery cell, and a battery module has an average of 750 battery cells, and the welding time is about 125 minutes), but also can greatly reduce the production equipment, production cost, welding tooling, process research and development cost and human resources of the battery module, so as to achieve the effect of low-cost and rapid production of battery modules.

[0032] Optionally, the material of the connection unit can be set to copper or aluminum, which can be selected according to actual needs. Copper is used as an example for description below.

[0033] According to the principle of thermal balance, as the busbar temperature rises, the temperature difference between it and the surrounding environment gradually increases, which makes the heat dissipation speed faster. Eventually, the heat dissipation speed is equal to the heat generation speed, and the copper busbar temperature remains stable, that is, the thermal balance state is maintained.

[0034] In the embodiment of the present application, the surface area of ​​the connecting unit satisfies the following formula 1. For specific calculation data, please refer to FIG8 :

[0035] (Formula 1)

[0036] in represents the total heat dissipation energy, The conductor absorbs heat energy, The Joule heat generated by the current, Indicates the amount of resistance loss.

[0037] Taking into account Much smaller than the Joule heat generated by the current , so in the calculation process, we can Therefore, formula 1 can be simplified to formula 2:

[0038] (Formula 2)

[0039] The meaning of the above formula 2 is: total heat dissipated + heat absorbed by the conductor = Joule heat generated by the current. The above formula is discussed in detail below.

[0040] The first part of formula 2 is:

[0041] The first part of formula 2 means: total heat dissipated. Where t represents the time from power on to thermal equilibrium; K is the thermal conductivity; is the surface area of ​​the connection unit; △T(t) is the temperature rise value corresponding to time t during the integration process, that is, the difference between the conductor temperature and the ambient temperature during the time 0~t, which is a function that changes with time; t in d(t) is the time coordinate value starting from the start of power-on.

[0042] The second part of formula 2 is the heat energy absorbed by the conductor: where C is the specific heat capacity of the connection unit; m is the mass of the connection unit; △T represents the temperature rise, and △T(t) is the temperature rise value corresponding to time t during the integration process.

[0043] The third part of formula 2 is the Joule heat generated by the current, where I is the rated current; R is the internal resistance of the connection unit; and T is the time from power-on to thermal equilibrium.

[0044] The surface area of ​​the connection unit can be calculated using the above formula 2.

[0045] By using the above formula 2, when the material of the connection unit is determined according to actual needs, the value of the thermal conductivity coefficient K is also determined.

[0046] Next, we derive the first part of the above formula 2:

[0047] In some examples, the total heat dissipation energy E0 can be divided into heat radiation heat dissipation E1 and heat convection heat dissipation E2, that is, E0=E1+E2.

[0048] First, for the calculation of heat radiation heat dissipation:

[0049]

[0050] In this formula: is the emissivity, and in some examples, Can be Or other values; B is the absolute temperature, B=t (degrees Celsius) + 273.15; t is the time from power-on to thermal equilibrium, t can be determined according to actual conditions, and in some examples t can be 1800s.

[0051] Secondly, for the calculation of heat convection heat dissipation:

[0052]

[0053] In this formula: α is set to represent the heat dissipation coefficient, and the unit is: The specific value of the heat dissipation coefficient is determined according to the application conditions, for example:

[0054] When cooled naturally, the copper surface is 5 and the aluminum surface is 7.5;

[0055] When water-cooled, the copper bar surface is 10, and the aluminum bar surface is 25;

[0056] When air-cooled, the copper bar surface is 25°C and the aluminum bar surface is 35°C.

[0057] In some implementations, the value of α may be 10.

[0058] △T represents the temperature rise, and t is the time from power on to thermal equilibrium. t can be determined based on actual conditions. In some examples, t can be 1800s. The following explains E0=E1+E2:

[0059] E0=E1+E2;

[0060]

[0061]

[0062]

[0063]

[0064] Among them, K=α+α2, α2=(K / 100)^4 / △T. By performing mathematical processing (calculus processing), we can obtain the first part of formula 2.

[0065] In other embodiments, other formulas may be combined to obtain the relationship between other parameters in the connection unit. For example: ;in, 5 , L is the length of the connecting unit in the current direction; b is the first side length; and a is the thickness of the connecting unit.

[0066] Through formula 2:

[0067]

[0068] Calculate After that, it can be combined , the relationship between a, b, and L is obtained, which facilitates technicians to optionally design the shape of the connecting unit.

[0069] Next, we will exemplify the formula For deduction, please refer to Figure 5. In the second connecting unit 203, the direction of current flow is from the first positive electrode connecting portion 21 to the first negative electrode connecting portion 31. The length of the second connecting unit 203 in the current direction is L, b is the first side length, and a is the thickness of the connecting unit. Please refer to Figure 5. The arrows M and N in Figure 5 roughly illustrate the thickness of the connecting unit. The surface area of ​​the second connecting unit 203 is for:

[0070] In order to make the overcurrent between the cells meet the requirements, an appropriate overcurrent value can usually be set, and the surface area of ​​the connecting unit can be further determined when the parameter values ​​such as thermal conductivity K, specific heat capacity C of the connecting unit, and mass m of the connecting unit are available and known. The surface area of ​​the connection unit calculated by the overflow value , which facilitates further determining the shape and size of the connecting unit. By connecting the connecting unit with at least two battery cells, the overcurrent requirements can be better met, and the overcurrent reliability between the battery cells and the busbar can be improved.

[0071] In some embodiments, under the action of short-term current, it can be approximately considered that the total Joule heat energy of the current acts entirely on the busbar temperature rise, that is, the value of the total heat dissipation energy is approximately 0. In this case, the total heat dissipation energy in Formula 2 is 0. In this case, Formula 2 can also be simplified to Formula 3:

[0072] (Formula 3)

[0073] Where C is the specific heat capacity of the connection unit; m is the mass of the connection unit; △T represents the temperature rise; I is the rated current; R is the internal resistance of the connection unit; and T is the time from power-on to thermal equilibrium.

[0074] By using Formula 3, the internal resistance R of the connection unit can be calculated after knowing the specific heat capacity C of the connection unit, the mass m of the connection unit, the temperature rise △T, the rated current I, and the time T from power-on to thermal equilibrium. Optionally, the formula can be combined:

[0075]

[0076] In this formula, is the density of the connecting unit. When the material of the connecting unit is determined, its value can also be determined. Please refer to Figure 5, which roughly illustrates a, b, and L, where L is the length of the connecting unit in the current direction; b is the first side length; a is the thickness of the connecting unit. The arrows M and N in Figure 5 roughly illustrate the thickness of the connecting unit, so that the relationship between a, b, and L can be calculated.

[0077] As shown in Figure 5, Figure 5 is a structural schematic diagram of the bus provided in an embodiment of the present application; in one embodiment, the first positive electrode connecting portion 21 is configured to be sleeved on the positive electrode 111 of the first battery cell 11, and the first positive electrode connecting portion 21 includes a first surrounding portion 210 configured to surround the positive electrode 111 of the first battery cell 11, and the first surrounding portion 210 is provided with a first elastic sheet 23, and the first elastic sheet 23 is configured to be interference fit with the positive electrode 111 of the first battery cell 11, and is electrically connected to the positive electrode of the first battery cell 11.

[0078] The first positive electrode connecting portion 21 includes a first surrounding portion 210 configured to surround the positive electrode 111 of the first battery cell 11. The first surrounding portion 210 is configured to surround the positive electrode 111 of the first battery cell. To achieve a stable connection between the positive electrode 111 of the first battery cell and the first positive electrode connecting portion 21, a first elastic piece 23 may be provided on the side of the first surrounding portion 210 facing the positive electrode 111 of the first battery cell 11 to achieve an elastic connection between the positive electrode 111 of the first battery cell and the first positive electrode connecting portion 21, thereby facilitating the installation of the positive electrode 111 of the first battery cell to the first positive electrode connecting portion 21. To prevent the positive electrode 111 of the first battery cell from being disconnected from the first positive electrode connecting portion 21, the positive electrode 111 of the first battery cell 11 is interference-fitted with the first elastic piece 23, and the positive electrode of the first battery cell 11 is electrically connected to the first elastic piece 23.

[0079] In the embodiment of the present application, a plurality of first spring clips 23 can be stamped out of a metal conductor. The first spring clips 23 are distributed in the shape of a battery cell pole. During installation, they can be assembled by simply pressing downward on the positive pole of the corresponding battery cell. This allows the positive pole of the first battery cell 11 to be electrically connected to the first spring clip 23. The positive pole 111 of the first battery cell 11 and the first spring clip 23 have an interference fit. The first spring clip 23 will tightly clamp the positive pole of the battery cell, ensuring normal overcurrent and charging and discharging of the battery cell. The first spring clip 23 is made of a conductive material, specifically copper, aluminum, etc.

[0080] As shown in FIG6 , in one embodiment, the middle portion of the first elastic piece 23 may be convex inward and configured to elastically abut against the outer circumference of the positive electrode 111 of the first battery cell 11, with the first elastic piece 23 being in electrical contact with the positive electrode 111 of the first battery cell. This achieves an interference fit between the positive electrode 111 of the first battery cell 11 and the first elastic piece 23, and the positive electrode of the first battery cell 11 is electrically connected to the first elastic piece 23.

[0081] As shown in Figure 5, Figure 5 is a structural schematic diagram of the bus provided in an embodiment of the present application; the first negative electrode connecting portion 31 is configured to sleeve the negative electrode 133 of the second battery cell 13, and the first negative electrode connecting portion 31 includes a second surrounding portion 310 configured to surround the negative electrode 133 of the second battery cell 13, and the second surrounding portion 310 is provided with a second elastic sheet 33, and the second elastic sheet 33 is configured to have an interference fit with the negative electrode 133 of the second battery cell 13, and is electrically connected to the negative electrode 133 of the second battery cell 13.

[0082] The first negative electrode connecting portion 31 includes a second surrounding portion 310 configured to surround the negative electrode 133 of the second battery cell 13. The second surrounding portion 310 is configured to surround the negative electrode 133 of the second battery cell 13. To ensure a stable connection between the negative electrode 133 of the second battery cell 13 and the first negative electrode connecting portion 31, the second surrounding portion 310 may be provided with a second elastic plate 33 on the side facing the negative electrode 133 of the second battery cell 13. This elastic plate 33 is provided to elastically connect the negative electrode 133 of the second battery cell to the first negative electrode connecting portion 31, facilitating installation of the negative electrode 133 of the second battery cell to the first negative electrode connecting portion 31. To prevent the negative electrode 133 of the second battery cell from being disconnected from the first negative electrode connecting portion 31, the negative electrode 133 of the second battery cell is interference-fitted with the second elastic plate 33, thereby electrically connecting the negative electrode 133 of the second battery cell to the second elastic plate 33. The first elastic plate 23 is made of a conductive material, specifically copper, aluminum, etc.

[0083] In the embodiment of the present application, a plurality of second spring clips 33 can be punched out of a metal conductor. The second spring clips 33 are distributed in a shape imitating a battery cell pole. When installing, it is only necessary to press down the negative pole of the corresponding battery cell to achieve assembly, so that the negative pole 133 of the second battery cell 13 is electrically connected to the second spring clip 33. The negative pole 133 of the second battery cell 13 is interference fit with the second spring clip 33. The second spring clip 33 will tightly clamp the negative pole 133 of the battery cell, thereby ensuring normal overcurrent and charging and discharging of the battery cell.

[0084] As shown in FIG7 , in one embodiment, the middle portion of the second elastic piece 33 may be inwardly convex and configured to elastically abut against the outer circumference of the negative electrode 133 of the second battery cell, with the second elastic piece 33 being in electrical contact with the negative electrode 133 of the second battery cell. In this way, an interference fit is achieved between the negative electrode 133 of the second battery cell 13 and the second elastic piece 33.

[0085] In one embodiment, the busbar and the positive and negative electrodes of the battery cell can both be fixed using a "spring-type" interference fit. Optionally, as shown in FIG5 , the first spring 23 extends along a first extension direction, and the second spring extends along a second extension direction, the first extension direction being opposite to the second extension direction.

[0086] Since the first elastic piece 23 extends along the first extension direction and the second elastic piece 33 extends along the second extension direction, that is, the first elastic piece 23 connected to the positive electrode and the second elastic piece 33 connected to the negative electrode extend in opposite directions, this ensures a stable connection between the connecting unit and the two battery cells and prevents the first and second elastic pieces from snapping out of the battery cells after being locked.

[0087] In one embodiment, as shown in FIG5 , the battery cell can be a cylindrical battery cell. The positive and negative electrodes of each battery cell are located at the top of the battery cell. The diameter of the positive electrode is smaller than that of the negative electrode. The diameter of the first surrounding portion 210 of the first positive electrode connecting portion is adapted to the positive electrode, and the diameter of the second surrounding portion 310 of the first negative electrode connecting portion is adapted to the negative electrode. This allows for better installation with the positive and negative electrodes of the battery cell.

[0088] As shown in Figure 5, the positive pole of each battery cell and the negative pole of the battery cell are arranged in steps, and the first surrounding portion 210 of the first positive pole connecting portion and the second surrounding portion 310 of each connecting unit are arranged in steps, the first surrounding portion 210 of the first positive pole connecting portion is adapted to the positive pole of the battery cell, and the second surrounding portion 310 of the first negative pole connecting portion is adapted to the negative pole of the battery cell.

[0089] In a specific embodiment, the connection unit may include a connection portion 51, which includes a first end 511 and a second end 513. The first end 511 is bent and connected to the first negative electrode connection portion 31, and the second end 513 is connected to the first positive electrode connection portion 21. The first negative electrode connection portion 31 is closer to the battery cell than the first positive electrode connection portion 21. Thus, by bending the first end 511 and connecting it to the first negative electrode connection portion 31, and connecting the second end 513 to the first positive electrode connection portion 21, the first negative electrode connection portion 31 is closer to the battery cell than the first positive electrode connection portion 21, thereby achieving a stepped arrangement of the first surrounding portion 210 and the second surrounding portion 310. This allows the first surrounding portion 210 to mate with the positive electrode of the battery cell, and the second surrounding portion 310 to mate with the negative electrode of the battery cell. This improves the connection between the first negative electrode connection portion 31 and the negative electrode of the battery cell, and the first positive electrode connection portion 21 and the positive electrode of the battery cell.

[0090] In one specific embodiment, the connection unit further includes an insulating film (not shown), and the insulating film is applied to both the side of the connection portion 51 facing the battery cell and the side of the connection portion facing away from the battery cell. This insulating film prevents the connection unit from causing a short circuit during installation, which could compromise electrical safety.

[0091] As shown in Figures 3 and 4, an embodiment of the present application also provides a busbar 200, which includes a plurality of connection units described in any of the above embodiments, and the first positive connection portion 21 and the first negative connection portion 31 in each of the connection units are arranged along the first direction, and the plurality of connection units are arranged along the first direction, and the two adjacent connection units arranged along the first direction are defined as a first connection unit 201 and a second connection unit 203, respectively. The first negative connection portion of the first connection unit 201 is sleeved on the negative pole of the first battery cell, the first positive connection portion 21 of the second connection unit 203 is sleeved on the positive pole 111 of the first battery cell 11, and the first negative connection portion of the second connection unit 203 is sleeved on the negative pole of the second battery cell.

[0092] Since the busbar 200 includes the connection unit as described in any of the above embodiments, it has the structure and function of the connection unit as described in any of the above embodiments. The specific structure and function of the connection unit have been stated above and will not be repeated here.

[0093] There are multiple connection units. For ease of understanding, two adjacent connection units arranged along the first direction are respectively the first connection unit 201 and the second connection unit 203. The first direction and the second direction form a preset angle, and the first direction and the second direction are not parallel.

[0094] The first positive electrode connection portion 21 of the second connection unit 203 is mounted on the positive electrode 111 of the first battery cell 11 and is electrically connected to the first positive electrode connection portion 21. The first negative electrode connection portion of the second connection unit 203 is mounted on the negative electrode of the second battery cell and is electrically connected to the negative electrode of the second battery cell. In this way, the positive electrode 111 of the first battery cell 11 and the negative electrode of the second battery cell are electrically connected via the second connection unit 203, thereby connecting the first and second battery cells in series.

[0095] The first negative electrode connection portion of the first connection unit 201 is mounted on the negative electrode of the first battery cell and electrically connected to the first negative electrode connection portion 31. The first positive electrode connection portion 21 of the second connection unit 203 is mounted on the positive electrode 111 of the first battery cell 11. The positive electrode 111 of the first battery cell 11 is electrically connected to the first positive electrode connection portion 21 of the second connection unit 203. The first negative electrode connection portion of the second connection unit 203 is mounted on the negative electrode of the second battery cell. Similarly, the first positive electrode connection portion of the first connection unit 201 can be mounted on the positive electrode of the third battery cell 14. In this way, the first battery cell 11, the second battery cell 13, and the third battery cell 14 are connected in series. This achieves the connection of multiple battery cells in series along the first direction through the busbar 200. The first positive electrode connection portion 21 and the first negative electrode connection portion 31 in each connection unit are arranged along the first direction, and multiple connection units are arranged along the first direction. In this way, the first battery cell 11 , the second battery cell 13 , and the third battery cell 14 are connected in series in the first direction.

[0096] As shown in FIG4 , the busbar further includes a parallel portion 207 and a third connection unit 205 arranged along the second direction with the second connection unit 203. The parallel portion 207 is configured to electrically connect the second connection unit 203 and the third connection unit 205. The parallel portion 207 is configured to connect the battery cells in parallel. The parallel portion can be configured to connect the first positive connection portion 21 of the second connection unit 203 and the first positive connection portion 21 of the third connection unit 205, or to connect the first negative connection portion of the second connection unit 203 and the first negative connection portion of the third connection unit 205, or to connect the connection portion 51 of the second connection unit 203 and the connection portion 51 of the third connection unit 205, etc., to achieve parallel connection of multiple battery cells.

[0097] The busbar includes a plurality of third connection units arranged along the second direction, and a plurality of parallel portions, with two adjacent third connection units 205 connected via a parallel portion 207. As shown in FIG5 , in one embodiment, three third connection units can be configured, and three parallel portions can be configured. Thus, a first connection unit 201 is adjacent to a third connection unit and connected via a parallel portion. The side of the third connection unit away from the first connection unit 201 is connected to two other third connection units via a parallel portion, and the other two third connection units are connected via a parallel portion.

[0098] The embodiment of the present application further provides a battery module, as shown in FIG1 , which is a schematic structural diagram of a battery module 300 provided in the embodiment of the present application.

[0099] The battery module 300 includes: a plurality of battery cells 100; and a busbar 200 as described in any of the above embodiments, wherein the busbar 200 is configured to connect the plurality of battery cells 100. The battery module 300 includes a busbar as described in any of the above embodiments, and thus has the structure and function of the busbar as described in any of the above embodiments. The specific structure and function of the busbar have been described above and will not be repeated here.

[0100] The battery module 300 provided in an embodiment of the present application includes a battery cell 100 and a busbar 200. The battery cell 100 is configured in multiples, and the busbar 200 is configured to connect multiple battery cells 100. The battery module provided in an embodiment of the present application includes at least two battery cells. When there are two battery cells, the two battery cells can be connected in series via the busbar. When there are three battery cells, one battery cell can be connected in series with two other battery cells, or one battery cell can be connected in series with another battery cell and in parallel with the remaining battery cell. In one specific embodiment, as shown in Figure 1, Figure 1 is a schematic structural diagram of the battery module 300 provided in an embodiment of the present application. The battery module may include multiple rows of battery cells arranged along the first direction, each row of battery cells including multiple battery cells arranged along the second direction. These battery cells can be connected in series and in parallel via the busbar 200. The angle between the first direction and the second direction can be less than 180 degrees. The specific number of battery cells can be configured according to actual needs and is not limited by this application.

[0101] Specifically, the battery cell can be a cylindrical battery cell, the positive pole and the negative pole of the battery cell are both arranged at the top of the battery cell, the diameter of the positive pole is smaller than the diameter of the negative pole, the diameter of the first surrounding portion 210 is adapted to the positive pole, and the diameter of the second surrounding portion 310 is adapted to the negative pole.

[0102] The positive and negative electrodes of the battery cells are arranged in a stepped pattern, and the first surrounding portion 210 and the second surrounding portion 310 are arranged in a stepped pattern. The first surrounding portion 210 is adapted to the positive electrode of the battery cell, and the second surrounding portion 310 is adapted to the negative electrode of the battery cell. The height H of the first surrounding portion 210 is within the range of 0 < H ≤ the height of the positive electrode column of the battery cell. This allows for a better fit around the positive electrode column of the battery cell.

[0103] As shown in Figure 2, Figure 2 is a top view of Figure 1; the battery module 300 also includes a positive bus 303 and a negative bus 305, and the buses are electrically connected to the positive bus and the negative bus respectively. The positive bus 303 is configured to connect the positive pole of the battery module 300, and the negative bus 3-5 is configured to connect the negative pole of the battery module 300.

[0104] The positive busbar 303 and the negative busbar 305 can be located on either side of the busbar 200 and configured to connect the positive and negative electrodes of the battery module 300, respectively. Multiple battery cells are connected in series and in parallel via the busbar 200, the positive busbar 303, and the negative busbar 305. The positive busbar 303 and the negative busbar 305 are configured as a busbar. The positive busbar 303 and the negative busbar 305 can be secured to the battery cell 100 in the same manner as the busbar 200. For example, a second positive electrode connection portion can be configured to fit over the positive electrode of a battery cell, the negative busbar is provided with multiple interconnected second negative electrode connection portions, and a second negative electrode connection portion can be configured to fit over the negative electrode of a battery cell. Because the positive and negative busbars need to be connected, their cross-sectional areas are increased. The output stage's overflow area can be calculated to match the overflow requirements of different systems. The proportion of the insulating film covering the busbar may range from 80% to 90%, for example, 80%, 83%, 85%, 86%, 87%, 88%, 89%, 90%.

[0105] In one embodiment, the total busbar area is 3041.627 mm², the insulation film area is 2555.384 mm², and the insulation film ratio is 2555 / 3041 = 84%. This provides better insulation and safer installation.

[0106] Specifically, the positive electrode bus is provided with a plurality of second positive electrode connection parts 3031 connected to each other, and one of the second positive electrode connection parts 3031 is configured to connect to the positive electrode of the battery cell; the negative electrode bus 305 is provided with a plurality of second negative electrode connection parts 3051 connected to each other, and one of the second negative electrode connection parts 3051 is configured to connect to the negative electrode of the battery cell.

[0107] Optionally, the battery module 300 also includes a flexible printed circuit (FPC) 302, located above the busbar 200, the positive busbar 303, and the negative busbar 305. This FPC is configured to collect and transmit voltage and temperature signals. During installation, first install the negative busbar, busbar 200, and the positive busbar 303, then the FPC.

[0108] After all battery modules are stacked, they are installed in a box, and all components are sealed with glue in the box. The glue can bond all components such as battery cells, busbar 200, positive busbar 303 and negative busbar 305, box body and box cover together to form a good structural strength. The glue sealing can also form a secondary reinforcement for the installation of the busbar and battery cell poles, which can completely prevent the busbar from loosening and make the entire battery system safer.

Claims

1. A connection unit, the connection unit is arranged to connect battery cells, the battery cells (100) at least include a first battery cell (11) and a second battery cell (13), and the connection unit includes: A first positive connection part (21), which is arranged to detachably connect the positive electrode (111) of the first battery cell (11) and is electrically connected to the positive electrode (111) of the first battery cell (11); A first negative connection part (31), which is arranged to detachably connect the negative electrode (133) of the second battery cell (13) and is electrically connected to the negative electrode (133) of the second battery cell (13); The first negative connection part (31) is connected to the first positive connection part (21) to connect the first battery cell (11) and the second battery cell (13) in series.

2. The connection unit according to claim 1, wherein the first positive connection part (21) is arranged to snap-connect to the positive electrode (111) of the first battery cell (11); The first negative connection part (31) is arranged to snap-connect to the negative electrode (133) of the second battery cell (13).

3. The connecting unit according to claim 2, wherein The first positive connection part (21) sleeves the positive electrode (111) of the first battery cell (11), and the first negative connection part (31) sleeves the negative electrode (133) of the second battery cell (13).

4. The connecting unit according to any one of claims 1 to 3, wherein, The method for obtaining the surface area of the connection unit is: Calculating the surface area of the connection unit according to the total heat dissipation energy, the conductor heat absorption energy, and the Joule heat generated by the current; or, Calculating the surface area of the connection unit according to the conductor heat absorption energy and the Joule heat generated by the current.

5. The connection unit according to any one of claims 1 to 4, further comprising a connection part, the first negative connection part (31) is connected to the first positive connection part (21) through the connection part (51), the connection part (51) includes a first end (511) and a second end (513), the first end (511) is bent and connected to the first negative connection part (31), and the second end (513) is connected to the first positive connection part (21).

6. The connecting unit according to claim 5, wherein, The connection part (51) is covered with an insulating film.

7. The connecting unit according to any one of claims 3 to 6, wherein, The first positive connection part (21) includes a first surrounding part (210), the first surrounding part (210) is arranged to sleeve the positive electrode (111) of the first battery cell (11) and is electrically connected to the positive electrode (111) of the first battery cell (11); and / or, The first negative connection part (31) includes a second surrounding part (310), the second surrounding part (310) is arranged to surround the negative electrode (133) of the second battery cell (13) and is electrically connected to the negative electrode (133) of the second battery cell (13).

8. The connecting unit according to any one of claims 3 to 6, wherein The first positive electrode connection part (21) includes a first surrounding part (210). The first surrounding part (210) is arranged to sleeved on the positive electrode (111) of the first battery cell (11) and is electrically connected to the positive electrode (111) of the first battery cell (11). The first surrounding part (210) is provided with a first elastic piece (23), and the first elastic piece (23) is arranged to have an interference fit with the positive electrode (111) of the first battery cell (11); and / or, The first negative electrode connection part (31) includes a second surrounding part (310). The second surrounding part (310) is arranged to surround the negative electrode (133) of the second battery cell (13) and is electrically connected to the negative electrode (133) of the second battery cell (13). The second surrounding part (310) is provided with a second elastic piece (33), and the second elastic piece (33) is arranged to have an interference fit with the negative electrode (133) of the second battery cell (13).

9. The connecting unit according to any one of claims 3 to 6, wherein, The first positive electrode connection part (21) includes a first surrounding part (210). The first surrounding part (210) is arranged to sleeved on the positive electrode (111) of the first battery cell (11) and is electrically connected to the positive electrode (111) of the first battery cell (11). The first surrounding part (210) is provided with a first elastic piece (23), and the first elastic piece (23) is arranged to have an interference fit with the positive electrode (111) of the first battery cell (11). The first negative electrode connection part (31) includes a second surrounding part (310). The second surrounding part (310) is arranged to surround the negative electrode (133) of the second battery cell (13) and is electrically connected to the negative electrode (133) of the second battery cell (13). The second surrounding part (310) is provided with a second elastic piece (33), and the second elastic piece (33) is arranged to have an interference fit with the negative electrode (133) of the second battery cell (13). The first elastic piece (23) extends along a first extension direction, the second elastic piece (33) extends along a second extension direction, and the first extension direction is opposite to the second extension direction.

10. A bus bar (200) includes a plurality of connection units as described in any one of claims 1-9. The first positive electrode connection part (21) and the first negative electrode connection part (31) in each connection unit are arranged along a first direction. The plurality of connection units are arranged along the first direction. Define two adjacent connection units arranged along the first direction as a first connection unit (201) and a second connection unit (203) respectively. The first negative electrode connection part (31) of the first connection unit (201) is sleeved on the negative electrode of the first battery cell (11). The first positive electrode connection part (21) of the second connection unit (203) is sleeved on the positive electrode (111) of the first battery cell (11). The first negative electrode connection part (31) of the second connection unit (203) is sleeved on the negative electrode (133) of the second battery cell (13).

11. The bus bar (200) according to claim 10 further includes a parallel connection portion (207) and a third connection unit (205) arranged along a second direction. The parallel connection portion (207) is configured to electrically connect the first connection unit (201) and the third connection unit (205), or electrically connect the second connection unit (203) and the third connection unit (205).

12. A battery module (300) includes: a plurality of battery cells (100); and the bus bar (200) according to claim 10 or 11, the bus bar (200) being configured to connect the plurality of battery cells (100).

13. The battery module (300) according to claim 12 further includes a positive bus bar (303) and a negative bus bar (305). The bus bar is electrically connected to the positive bus bar (303) and the negative bus bar (305) respectively. The positive bus bar (303) is configured to connect to the positive electrode of the battery module (300), and the negative bus bar (305) is configured to connect to the negative electrode of the battery module (300).

14. The battery module (300) according to claim 13, wherein, The positive bus bar (303) is provided with a plurality of interconnected second positive connection portions. One of the second positive connection portions is configured to be clamped to the positive electrode of a battery cell. The negative bus bar (305) is provided with a plurality of interconnected second negative connection portions (3051). One of the second negative connection portions (3051) is configured to be clamped to the negative electrode of a battery cell.

15. The battery module (300) according to any one of claims 12 to 14, wherein, The battery cell (100) is a cylindrical battery cell. The positive electrode and the negative electrode of each battery cell (100) are both provided at the top end of the battery cell (100). The diameter of the positive electrode is smaller than the diameter of the negative electrode. The diameter of the first positive connection portion (21) is adapted to the positive electrode, and the diameter of the first negative connection portion (31) is adapted to the negative electrode.

16. The battery module (300) according to claim 15, wherein, The positive electrode and the negative electrode of each battery cell (100) are arranged in a stepped manner. The first positive connection portion (21) and the first negative connection portion (31) of each connection unit are arranged in a stepped manner. The first positive connection portion (21) is adapted to the positive electrode, and the first negative connection portion (31) is adapted to the negative electrode.

17. The battery module (300) according to any one of claims 12 to 16, wherein, The first positive connection portion (21) includes a first surrounding portion (210). The first surrounding portion (210) is electrically connected to the positive electrode (111) of the first battery cell (11). The value range of the height H of the first surrounding portion (210) is: 0 < H ≤ the height of the positive electrode column of the battery cell.

18. The battery module (300) according to claim 13 or 14 further includes an FPC. The FPC (302) is arranged above the bus bar (200), the positive bus bar (303) and the negative bus bar (305).

19. For the battery module (300) according to any one of claims 12 to 18, the bus bar (200) is covered with an insulating film. The proportion range of the insulating film covering the bus bar is: 80% - 90%.

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