Arrangement and method for replacing battery module or battery compartment in battery pack of electric passenger vehicle or commercial vehicle

Abstract

The invention relates to a method for replacing a battery module of a battery pack or a battery compartment of a battery pack in an electric commercial vehicle, the battery pack and the battery compartment each having a plurality of battery modules comprising individual battery cells. The method comprises the following steps: according to step a), arranging battery jars in pairs in parallel inside the battery pack, the battery jars having different states of health and / or aging parameters; according to the step b), a resistor is arranged on each parallel battery jar, the resistor adopts the same resistance value for each parallel battery jar, or a variable resistor is configured for each battery jar; according to step c), a battery control unit and a corresponding resistance switch are provided for each of the first to third resistors or for a variable resistor on each battery compartment. In addition, the invention also relates to the application of the method in the aspect of replacing the battery module in the battery pack of the electric commercial vehicle, and the application of the battery structure in the aspect of replacing the battery module in the battery pack of the electric commercial vehicle.

Description

Technical Field

[0001] The present invention relates to a method for replacing battery modules and battery slots in a battery pack for an electric vehicle, the battery pack comprising a plurality of battery slots, each battery slot having a plurality of battery modules containing individual battery cells. Background Technology

[0002] US2019 / 0160972A1 relates to a scalable power unit for driving one or more electric drives in a vehicle and / or as part of outdoor-use equipment. The battery packs can be housed in battery cases or arranged in a stacked configuration to achieve a scalable power unit. Each battery pack can be detached and used individually or added to a combination of battery packs.

[0003] US2017 / 0194673A1 relates to a control device for a battery that transmits status information to a main controller. For example, a reference temperature range and a predetermined temperature range for subsequent time points can be determined.

[0004] Today, battery-powered commercial vehicles, such as N3 category (12 to 40-ton) electric trucks, use batteries with capacities up to 500 kWh and voltages up to 800 volts. These battery packs consist of multiple individual batteries (also called battery cells) connected together. Connection methods include parallel and series connections; parallel connections achieve the required capacity, while series connections achieve the required voltage. Each battery cell consists of multiple battery modules, and each battery module consists of multiple individual battery cells. This battery structure is used in applications such as electric buses and mobile electric work machinery (e.g., excavators).

[0005] If a single cell in a battery module within a battery cell fails, typically, if a bypass switch is present, at least the entire battery module will be shut down. Consequently, the voltage of that battery module will decrease, and other intact modules in the parallel branch of the same battery cell, as well as modules from parallel battery cells, must also be bypassed (überbrücken, bridging) to maintain the voltage level.

[0006] However, if individual battery modules cannot be bypassed, the entire battery cell containing a faulty individual cell or module, as well as parallel battery cells, may be bypassed. Typically, the battery cell voltage is 400 volts, similar to battery packs in electric passenger vehicles. The resulting voltage drop can prevent the electric truck's motor from providing the torque required for propulsion / operation. Therefore, in this case of damage, the entire battery pack needs to be replaced.

[0007] Replacing the faulty battery compartment is feasible, but in this case, managing the balancing current between the compartments becomes challenging due to differences in their State of Health (SoH). Replacement is only possible when the SoH differences between the parallel battery compartments are small. When the SoH differences are large (which typically occurs after the battery has been running for a long time, as most faults appear with increased operating time, by which time the SoH has decreased), the aforementioned problems arise. Therefore, whether replacing a battery compartment is cost-effective or installing a new battery pack is a better option is a cost issue. Since the battery is the most expensive component in the powertrain, replacing the entire battery pack is almost an economical loss for electric trucks, thus increasing the need for an economically viable solution to this problem. Furthermore, replacing only one battery compartment could increase the acceptance of electric trucks due to its economic and ecological advantages.

[0008] The problem isn't just with faulty battery modules; it's also with severely aged battery modules (SoH below 80%) within a battery cell, requiring the replacement of the entire battery cell containing the faulty module. Currently, the number of electric trucks in service is relatively small, and their batteries are still in near-new condition, so these issues haven't become apparent. However, this will change as batteries age, necessitating proactive solutions. Currently, replacing a battery cell with one of similarly aged characteristics when a battery cell in a battery pack fails is often impossible due to the scarcity of such cells. Summary of the Invention

[0009] According to the present invention, a method for replacing battery modules or battery slots of a battery pack is provided, wherein the battery pack includes multiple battery slots, each battery slot having multiple battery modules containing individual battery cells, and the method includes the following steps: a) The battery cells are arranged in pairs in parallel inside the battery pack, wherein each battery cell has a different state of health (SoH) and / or aging parameters. b) A resistor is provided on each parallel battery slot, wherein the resistor has the same resistance value for each parallel battery slot; or, a variable resistor is provided that can be connected to each parallel battery slot. c) On each battery slot, a battery control unit (BCU) and a corresponding resistor switch are provided for each resistor or for a variable resistor that can be connected in parallel with each battery slot; and d) Replace the aging or faulty battery compartment with a new battery compartment and adjust the equalization current by operating a pair of resistor switches simultaneously; or, with one resistor switch open, adjust the voltage by operating the first and second resistor switches in sequence; or, with the first resistor switch open, adjust the voltage by operating the third and second resistor switches in sequence.

[0010] In an advantageous improvement to the method proposed according to the invention, these resistive switches are first closed in the same state and then opened after voltage equalization.

[0011] In the method proposed according to the present invention, the switching on or off of the resistor is performed by resistor switches, which are controlled by corresponding BCUs.

[0012] In an advantageous improvement to the method proposed according to the invention, when a voltage difference ΔU is generated due to battery discharge during driving, the equalizing current caused by the replacement battery cell will result in a greater load on the replacement battery cell than on the remaining battery cell, causing the voltage of the replacement battery cell to drop faster, while the remaining battery cell will be charged through the equalizing current. This ensures that the voltage levels of the replacement battery cell and the remaining battery cell, which have different aging states, are balanced.

[0013] In an advantageous improvement to the method proposed according to the invention, it is specified that when the voltage difference ΔU exceeds a threshold, the third resistor switch corresponding to the new battery cell to be replaced is closed, wherein the equalizing current flows through the parallel resistor, thereby reducing the voltage and matching the voltage of the remaining battery cell.

[0014] In an advantageous improvement to the method proposed according to the invention, the third resistor switch is further specified as follows: the third resistor switch is controlled by the BCU corresponding to the new battery slot being replaced, the battery control unit measuring the voltage of the new battery slot being replaced and the voltage value of the remaining battery slots, and sending these voltage values ​​to the master control unit (Master-BCU), the master control unit determining from which voltage difference threshold to start turning on the third resistor.

[0015] Furthermore, the method proposed according to the present invention specifies that: in the vehicle stopped state, and the first to sixth switches of the first to third branches and switch S 11 S 13 S 21 S 23 S 31 and S 33 When both are disconnected, the degree of slack in the battery slots will differ; check the voltage value before starting and close the first and second resistor switches until voltage equalization is achieved between the remaining battery slots and the new replacement battery slots.

[0016] Furthermore, the present invention also relates to a battery structure for an electric commercial vehicle, the battery structure comprising at least one battery pack having at least a plurality of first parallel battery slots and at least a plurality of second parallel battery slots, and further comprising a Master-BCU and BCUs corresponding to each battery slot. It is specified that a first resistor, a second resistor, and a third resistor are respectively connected in parallel with each parallel battery slot containing at least one replacement battery slot, and each resistor corresponds to a first to third resistor switch operable by the BCU.

[0017] In another implementation variant, the battery structure is designed such that instead of three identical resistors, a single variable resistor is provided, which is connected in parallel with all the parallel battery cells containing at least one replacement battery cell. This variable resistor is switched by the respective BCU of each battery cell via a first, second, or third resistor switch.

[0018] Furthermore, this invention also relates to the application of the method in replacing battery modules in electric commercial vehicle battery packs, and the application of the battery structure in replacing battery modules in electric commercial vehicle battery packs.

[0019] Advantages of the present invention The present invention provides a battery structure, a battery slot replacement method, and an operational method for cooperating with existing remaining battery slots. The present invention enables battery slot replacement from both structural and operational perspectives within the overall connection structure of an electric commercial vehicle battery pack. Compared to replacing the entire battery pack, the method and battery structure proposed in this invention offer significant economic and ecological advantages, resulting in substantial sustainability advantages. Furthermore, the present invention, through a resistor switch switching strategy for parallel resistors, prevents or controls the occurrence of battery balancing currents that could damage the battery.

[0020] After a one-time hardware installation, another battery cell can be replaced at a later time within the same parallel circuit, for example, when the SOH of a certain battery cell drops significantly. The solution proposed according to this invention also allows for hardware installation during the initial integration of the battery into a new vehicle, facilitating potential replacements later. Software connectivity can be established between the BCU of each battery cell and the Master-BCU of the battery system, thus eliminating the need for software updates. Only the faulty battery cell needs to be replaced, with hardware installation performed as necessary.

[0021] The solution proposed according to the present invention can be applied not only to large traction batteries in electric commercial vehicles (such as electric trucks, electric buses, or electric tractors), but also to traction batteries in electric passenger vehicles. Compared to previous solutions that involved replacing the entire battery pack, the solution proposed according to the present invention can be implemented at a lower cost. If, over time, the aging of a particular battery component or battery cell accelerates, the method can also utilize the same hardware to achieve voltage regulation. This is achieved by sequentially operating the corresponding resistor switches. Furthermore, it should be emphasized that the method proposed according to the present invention can also be applied after charging. Attached Figure Description

[0022] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings and the following description.

[0023] Attached image: Figure 1 Battery structure of electric commercial vehicles based on existing technology; Figure 2 The first implementation variant of the battery structure having identical resistors R1 to R3 connected in parallel; Figure 3 Another embodiment of the battery structure with variable resistance R proposed according to the present invention; Figure 4 Schematic diagram of voltage balancing under small balancing current; Figure 5 A schematic diagram of voltage equalization with the required equalization resistors; and Figure 6 : A schematic flowchart of the method proposed according to the present invention.

[0024] according to Figure 1 As shown, an exemplary battery structure for use in electric commercial vehicles (e-NKW) can be understood. For electric passenger vehicles (e-PKW), the battery pack (voltage level approximately 400 volts) consists of multiple modules with voltages ranging from 48 volts to 60 volts. Multiple battery modules are connected in series to achieve a voltage level of approximately 400 volts. To obtain higher capacity at 400 volts, multiple (e.g., three) battery modules are connected in parallel. Therefore, a total of twelve or twenty-four modules are produced, each containing 10 to 12 battery cells, each with a maximum voltage of approximately 4.2 volts. The battery pack used in electric commercial vehicles (voltage level approximately 800 volts) consists of multiple sub-cells. At least two sub-cells, each with a voltage level of 400 volts, are required and connected in series to achieve the desired voltage level of approximately 800 volts. Electric commercial vehicles necessarily require high capacity, which means that multiple such sub-cells need to be connected in parallel. Figure 1The diagram shows two sub-cells connected in series and three in parallel, for a total of six sub-cells. These sub-cells are also referred to as battery cells. These battery cells contain battery modules, and battery modules contain individual battery cells, similar to the battery structure of electric passenger vehicles.

[0025] Depend on Figure 1 It is known that the battery structure 10 has a master control unit (Master-BCU) 12 and a switching unit 14, through which the first to sixth switches 16-26 of the battery structure 10 can be controlled. According to Figure 1 The battery structure 10 includes a first branch 30, a second branch 32, and a third branch 34. The first branch 30 is switched via a first switch 16 and a fourth switch 22, while the second branch 32 is switched via a second switch 18 and a fifth switch 24. Finally, according to... Figure 1 The third branch 34 of the battery structure 10 is switched via a third switch 20 and a sixth switch 26. The dashed line indicates the battery pack 28. Inside the battery pack 28, for example, there is a first parallel battery slot 36 and a second parallel battery slot 38. More or fewer battery slots can also be installed inside the battery pack 28; this is just an example.

[0026] according to Figure 1 As shown, it can also be seen that, for example, within the range of the second parallel battery slot 38, each battery slot shown in the figure (i.e., battery slot 2 46, battery slot 4 50 and battery slot 6 56) contains a battery module 40, and each battery module 40 shown in the figure is composed of multiple battery cells 42.

[0027] Each second parallel battery slot 38 corresponds to a battery control unit (BCU) 60. Similarly, according to... Figure 1 As shown, battery slots 1 44, 3 48, and 5 52 in the first parallel battery slot 36 are similar. Each BCU 60 corresponding to battery slots 44, 46, 48, 50, 52, and 56 is connected to the control line 62 (shown as a dashed line here) via a control line according to... Figure 1 The Master-BCU12 connection of the battery structure 10 shown.

[0028] according to Figure 1 As shown, it can also be seen that each battery slot 44, 46, 48, 50, 52, and 56 corresponds to a current sensor 58.

[0029] Figure 1 It is also shown that each BCU 60 of battery compartments 1 44, 2 46, 3 48, 4 50, 5 52 and 6 56 controls switch S via its control line 62. 11 S 21 S 31 S 13 S23 and S 33 Other switches S are also connected in parallel with the aforementioned battery compartments 1-6 (44-56). 12 S 22 S 32 S 14 S 24 and S 34 .based on Figure 1 The battery structure 10 for electric commercial vehicles shown below will be described in the following section, which presents a battery system structure according to the present invention and a method for replacing battery modules from a battery pack in an electric commercial vehicle. Detailed Implementation

[0030] In the following description of embodiments of the present invention, the same or similar elements are referred to by the same reference numerals, and in some cases, these elements will not be described again. The accompanying drawings are only schematic illustrations of the subject matter of the present invention.

[0031] This invention relates to the replacement of battery modules in electric passenger vehicles and the replacement of battery slots in battery packs of electric commercial vehicles.

[0032] Figure 2 A first embodiment of the battery structure proposed according to the present invention is shown, which has resistors R1, R2 and R3 that are substantially connected in parallel.

[0033] according to Figure 2 As shown, the battery structure 10 proposed according to the present invention includes three parallel battery branches in its first embodiment, namely, a first branch 30, a second branch 32, and a third branch 34. Figure 2 In the first embodiment of the battery structure 10 proposed according to the present invention, resistors R1, R2, R370, R2, and R474 are connected in parallel with all the parallel battery cells 2, 4, 6, 46, 50, and 56, respectively. Figure 2 In the illustrated implementation variant, battery slot 6 56 is a new battery slot with initial performance, used to replace a faulty battery slot.

[0034] according to Figure 2As shown, the resistors (i.e., the first resistor R170, the second resistor R272, and the third resistor R374) are designed to have the same, unchanging resistance value. The specifications of resistors R1, R2, R370, R2, and R374 are primarily determined by the expected maximum balancing current and the heat dissipation capacity of resistors R1, R2, R370, R2, and R374, thereby determining the maximum duration of voltage balancing. The switching on and off of the aforementioned resistors R1, R2, R370, R2, and R374 is achieved through resistor switches, namely the first resistor switch SR176, the second resistor switch SR278, and the third resistor switch SR380. The aforementioned first, second, and third resistor switches SR1, SR2, SR376, SR380 are controlled by respective BCUs 60 corresponding to battery slots 2, 4, 46, 50, and 56. For this purpose, a control line 62 extends from each BCU 60 of the battery slots 2, 4 and 6 46, 50, 56 to each of the first, second and third resistor switches SR1, SR2, SR3 76, 78, 80.

[0035] According to Figure 2 The first implementation variant shown is different. Figure 3 The illustrated variant uses only one resistor, a variable resistor R 82, whose resistance value can be flexibly adjusted. This variable resistor R 82 is connected in parallel with all the parallel battery slots (i.e., battery slots 246, 450, and 656). Battery slots 2, 4 and 646, 50, 56 are connected in parallel with each other, wherein battery slot 656 is a new battery slot with entirely new performance, used to replace a faulty battery slot.

[0036] according to Figure 3 As shown, in this embodiment, the variable resistor R 82 can be connected in parallel with each of the aforementioned battery slots 2, 4 and 6 46, 50, 56 via multiple control lines 62.

[0037] The following will be combined with the second parallel battery compartment 38 (see according to...) Figure 1 The diagram illustrates a method for replacing the battery module 40 in a battery pack 28 of an electric commercial vehicle (e-NKW) according to the present invention. However, this is merely an example. It is also possible to combine this method with the method described in the diagram. Figure 1 , Figure 2 and Figure 3 The first parallel battery compartment 36 shown is used to explain the method proposed according to the present invention.

[0038] The method for replacing battery module 40 in battery pack 28 according to the present invention is performed by the Master-BCU 12 in conjunction with the respective associated BCU 60 of the corresponding parallel battery slot (in the present case, the second parallel battery slot 38, comprising battery slots 2 46, 4 50 and a replacement, unused battery slot 6 56). When replacing a faulty battery slot, a new battery slot (in the present case, battery slot 6 56) needs to be installed, and the voltage value of the new battery slot should be the same as the voltage value of the remaining two parallel battery slots in battery pack 28 (in this example, battery slots 2 46 and 4 50). This means that the new battery slot (in this example, battery slot 6 56) needs to be charged or discharged accordingly. If the electric commercial vehicle is not pre-installed with the above hardware, it needs to be integrated. In addition, electrical interfaces need to be established with each BCU 60 corresponding to battery slot 2 46, battery slot 4 50 and new battery slot 6 56, and connections need to be established with the corresponding first, second and third resistor switches SR1, SR2, SR376, 78 and 80 that need to be activated.

[0039] If battery slots 2, 4, 6, 46, 50, and 56 discharge during driving, the aging battery slots (currently slots 2, 46, and 4, 50) will discharge faster than the newer slot 6, 56, resulting in a faster voltage drop. According to the current shunt law, current will be distributed to the parallel battery branches 60, 32, and 34. Because the resistance of the aging battery is greater than that of the new battery, the current flowing through the aging battery is smaller. Due to these effects, the voltage change curves of the aging battery slots (currently slots 2, 44, and 4, 50) will tend to coincide with the voltage change curve of the newer slot 6, 56.

[0040] However, if a voltage difference ΔU 104 persists for a short period, the balancing current from the replaced battery slot 6 56 will place a greater load on that new slot than on the aging battery slots (currently slots 2 46 and 450). This will cause the voltage of the new battery slot 6 56 to drop faster, while the aging battery slots 2 46 and 4 50 will be charged by the balancing current. This situation is as follows... Figure 4 As shown.

[0041] Figure 4In the diagram, voltage change curve 90 is plotted along time axis 92. An axis parallel to time axis 92 displays the percentage of the State of Charge (SoC) 94. An balancing voltage U_Ausgleich 96 exists during balancing time 98 δt, generating the aforementioned balancing currents, which are charging currents for aged battery cells 246 and 450. On one hand, the balancing current is an additional discharging current for new battery cell 656; on the other hand, it is a charging current for aged battery cells 246 and 450.

[0042] If the equalization current increases due to an excessively large voltage difference ΔU 104 (i.e., the voltage difference ΔU 104 exceeds the threshold), then the third resistor switch SR380 will close. This allows the equalization current to flow through the parallel resistor (in this case, the third resistor R374), thereby reducing the voltage and matching it to the voltages of the two aged battery cells 246 and 450. This situation is as follows: Figure 5 As shown.

[0043] The third resistor switch SR380 is controlled by the BCU60 corresponding to battery slot 6 (i.e., the new battery slot 56 with essentially brand-new performance). BCU60 measures the voltage inside battery slot 6 56 and the battery voltage values ​​of the aged battery slots 2 46 and 4 50, and transmits these voltage values ​​to Master-BCU12. Master-BCU12 determines at what voltage difference threshold to begin energizing the equalizing resistor. In this case, Master-BCU12 sends a command via the control line or Controller Area Network (CAN) to the BCU60 corresponding to battery slot 6 (i.e., the replaced new battery slot 56) to close the third resistor switch SR380 until the voltage difference is below the threshold minus the hysteresis, thus preventing frequent toggling of the third resistor switch SR380. This ensures that the two aged battery slots 2 46 and 4 50 do not need to be shut down. Shutting down these two battery slots would result in a significant loss of capacity and a near-sudden, drastic drop in the power of the electric truck.

[0044] If an electric truck stops with the same voltage in the parallel battery slots 2, 4, 6, 46, 50, and 56, and these battery slots are in a relaxed state, then an equalization current will be generated during the relaxation process, but this equalization current is harmless.

[0045] For those systems that, in addition to disconnecting switches 1 to 6 (16-26), also disconnect the battery switch S during shutdown... 11 S 13 S 21 S 23 S 31 and S 31However, the situation is different for vehicles where all battery slots 1-6, 44, 46, 48, 50, 52, and 56 are in a disengaged state.

[0046] Because the slack levels of the various battery cells 1-6 (44, 46, 48, 50, 52, 56) may differ, the voltage difference may be too large upon the next vehicle start-up. This could cause a short-term, large equalization current generated by the aging battery cells to severely damage the new battery cell 6 (56). To address this, the method proposed according to this invention can be used: the voltage value is detected at startup, and if necessary, the first resistor switch SR176 and the second resistor switch SR278 are operated until voltage equalization is achieved between the aging battery cells (in this case, battery cells 2 (46) and 4 (50)) and the new battery cell 6 (56). During this period, the vehicle can start, but only at two-thirds of its power. The third resistor switch SR380 remains open; the first and second resistor switches SR176 and SR278 remain closed until voltage equalization is achieved, and then open. Subsequently, the vehicle can recover full power. In this scenario, simply starting the electric truck and operating the electrical auxiliary equipment helps to reduce the voltage, thereby significantly shortening the equalization time; and the driver will not perceive a power drop.

[0047] The same situation occurs after the charging process, if the aforementioned battery switch S 11 S 13 S 21 S 23 S 31 and S 33 During the subsequent relaxation phase, it is in the off state. At this time, the voltage of the new battery slot 6 56 will be too high, so the third resistor switch SR380 must be closed until the voltage reaches equilibrium. During this period, battery switch S 13 and S 23 When disconnected, only one-third of the electrical power is available. In this situation, starting the electric truck and running the electric auxiliary equipment will not cause the driver to feel a drop in power. The size of the balancing resistor also determines the time required to restore full power.

[0048] In the method proposed according to the present invention, either the switches SR176 and SR278 of the aged battery compartments (in the current case, battery compartments 2 46 and 4 50) are closed, or the third resistive switch SR380 corresponding to the new battery compartment 6 56 is closed, but both are never allowed to be closed simultaneously. Therefore, the resistive switches SR1, SR2 and SR376, 78, 80 must be interlocked accordingly. Ideally, both sets of switches are in the open state.

[0049] If one of the aging battery slots (in the current case, battery slot 2 46 or battery slot 4 50) ages more rapidly over time, the same hardware can be used to achieve voltage regulation by sequentially operating the first resistor switches SR176 and SR278 with the third resistor switch SR380 open, or sequentially operating the third resistor switch SR380 and the second resistor switch SR278 with the first resistor switch SR176 open. In the latter case, the interlocking is applied in a modified manner.

[0050] Using the battery structure 10 proposed according to the present invention (e.g.) Figure 2 and Figure 3 (As illustrated), it can economically and easily complete the task of replacing the battery or battery module 40.

[0051] Finally, according to Figure 6 A flowchart illustrating the various steps of the method proposed according to the present invention is shown in an illustrative manner.

[0052] Figure 6 The display shows that, starting from start 120, battery pack 28 is discharged in operating mode 122. Then, voltage detection 124 is performed on the parallel battery cells 1-6 (44, 46, 48, 50, 52, 56). Subsequently, during data transmission 126, these voltage data are transmitted to Master-BCU 12. In query 128, the extent to which the voltage difference 104 exceeds a threshold is compared. If the threshold is not exceeded, voltage detection 124 is returned; if the query result indicates that the threshold is exceeded, the relevant switch SR 130 is closed. x This connects the corresponding balancing resistor 132, and performs additional discharge through this resistor in step 134. Afterwards, the voltage difference ΔU in step 136 is compared again with the threshold minus the safety amount x. If the comparison result is negative, the process returns to voltage detection 124; if the comparison result is positive, the previously closed relevant switch SR is reopened in step 140. x Then the process ends at 142.

[0053] This invention is not limited to the embodiments described herein and the aspects emphasized therein. Rather, various modifications can be made by those skilled in the art within the scope defined by the claims, all of which fall within the conventional scope of the art.

Claims

1. A method for replacing a battery module (40) or a battery compartment (44-56) of a battery pack (28) in an electric commercial vehicle, the battery pack and the battery compartment each having a plurality of battery modules (40) comprising individual battery cells (42), the method comprising the following steps: a) The battery cells (46, 50, 56) are arranged in pairs in parallel inside the battery pack (28), wherein the battery cells (46, 50, 56) have different health status SoH and / or aging parameters; b) A resistor (70, 72, 74) is provided on each of the parallel battery slots (46, 50, 56), wherein the resistor (70, 72, 74) uses the same resistance value for each of the parallel battery slots (46, 50, 56); or, A variable resistor (82) is provided, which can be connected to each of the battery slots (44-56) in the parallel battery slots (36, 38); c) On each battery slot (44-56), set up a battery control unit (BCU) (60) and a corresponding resistor switch (76, 78, 80) for each resistor (70, 72, 74) or for a variable resistor (82) that can be connected to each battery slot (44-56) in parallel (36, 38). d) Replace the aged or faulty battery compartment with a new battery compartment (60) and avoid balancing current by operating the resistor switches (76, 78, 80) in pairs; or, with the third resistor switch (80) open, perform voltage regulation by operating the first and second resistor switches (76, 80) in sequence; or, with the first resistor switch (76) open, perform voltage regulation by operating the third and second resistor switches (80, 78) in sequence.

2. The method according to claim 1, characterized in that, The resistor switches (76, 78, 80) are first closed in the same state, and then opened after the voltage is balanced.

3. The method according to claims 1 and 2, characterized in that, The first to third resistors (70, 72, 74) are switched on or off by the first to third resistor switches (76, 78, 80), which are controlled by the corresponding battery control unit (BCU).

4. The method according to claims 1 to 3, characterized in that, During operation, when a voltage difference ΔU (104) is generated due to the discharge of the battery cells (46, 50, 56), the load of the equalizing current from the replacement battery cell (56) on the replacement battery cell is greater than the load on the remaining battery cells (46, 50), causing the voltage of the replacement battery cell (56) to drop faster, while the remaining battery cells (46, 50) are charged by the generated equalizing current.

5. The method according to claim 4, characterized in that, When the voltage difference ΔU (104) exceeds the threshold, the third resistor switch (80) corresponding to the new battery slot (60) is closed, so that the equalizing current flows through the parallel third resistor (74), thereby reducing the voltage and matching the voltage with the voltage of the remaining battery slots (46, 50).

6. The method according to claims 4 and 5, characterized in that, The third resistor switch (80) is controlled by the battery control unit (BCU) (60) corresponding to the replacement new battery slot (56). The battery control unit measures the voltage of the replacement new battery slot (56) and the voltage values ​​of the remaining battery slots (46, 50) and transmits these voltage values ​​to the master control unit Master-BCU (12). The master control unit determines from which voltage difference threshold the third resistor (74) is turned on.

7. The method according to claims 1 to 6, characterized in that, With the vehicle stopped and switches 1 to 6 (16-26) open, and switches S of branches 1 to 3 (30, 32, 34) closed. 11 S 13 S 21 S 31 S 33 When disconnected, the battery slots (46, 50, 56) have different degrees of slack; before the vehicle is started, the voltage value of the battery slots is queried and the first and second resistor switches (76, 78) are closed until voltage equalization is achieved between the remaining battery slots (46, 50) and the replacement new battery slot (56).

8. A battery structure (10) for an electric commercial vehicle, the battery structure comprising at least one battery pack (28), the battery pack having at least a plurality of first parallel battery slots (36) and at least a plurality of second parallel battery slots (38), further comprising a master control unit Master-BCU (12) and battery control units BCU (60) corresponding to each of the battery slots (44, 46, 48, 50, 52, 56), characterized in that, Each of the parallel battery slots (44, 46, 48, 50, 52, 56) containing at least one replacement new battery slot (56) is connected in parallel with a first resistor, a second resistor and a third resistor (70, 72, 74), and each resistor corresponds to a resistor switch (76, 78, 80) that can be controlled by the battery control unit BCU (60).

9. A battery structure (10) for an electric commercial vehicle, the battery structure comprising at least one battery pack (28), the battery pack having at least a plurality of first parallel battery slots (36) and at least a plurality of second parallel battery slots (38), further comprising a master control unit Master-BCU (12) and battery control units BCU (60) corresponding to each of the battery slots (44, 46, 48, 50, 52, 56), characterized in that, A variable resistor (82) is connected in parallel with all the parallel battery slots (44, 46, 48, 50, 52, 56), the parallel battery slots including at least one replacement new battery slot (56), the variable resistor (82) being switchable via the battery control unit (BCU) (60) of each battery slot (44, 46, 48, 50, 52, 56) by means of the first, second, or third resistor switch (76, 78, 80).

10. The application of the method according to any one of claims 1 to 7 in replacing the battery module (40) of the battery pack (28) of an electric commercial vehicle.

11. The application of the battery structure (10) according to any one of claims 8 and 9 in replacing the battery module (40) of the battery pack (28) of an electric commercial vehicle.

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