Battery power module copper bar sampling circuit

Abstract

The utility model discloses a battery power module copper bar sampling circuit which comprises a battery module I, a battery module II, a copper bar connecting the battery module I and the battery module II and an AFE chip, the battery module I, the copper bar and the battery module II are sequentially connected in series, one end of the copper bar is connected with a battery anode at the tail end of the battery module I, and the other end of the copper bar is connected with a battery cathode at the tail end of the battery module II. One end of the AFE chip is connected with a head end battery cathode of the battery module I, the other end of the AFE chip is connected with a head end battery cathode of the battery module II, a sampling channel of the AFE chip is respectively connected with anodes and cathodes of batteries in the battery module I and the battery module II, and the anode of a first battery of the battery module I and the cathode of a second battery of the battery module I are connected with the same sampling channel, and so on. The positive electrode of the last but one battery of the battery module II and the negative electrode of the last but one battery are connected with the same sampling channel; and the positive electrode of the last battery of the battery module I and the negative electrode of the first battery of the battery module II are connected with the same sampling channel. The problem that battery sampling channels are not enough due to module copper bar connection is solved.

Description

Technical Field

[0001] The utility model belongs to the technical field of lithium batteries, and particularly relates to a copper row sampling circuit for a battery power module. Background Art

[0002] At present, the internal modules of the power battery system of non-road vehicles are all electrically connected through flexible copper bars. Because of the good conductivity of the flexible copper bars, with the outer insulation protection and the flexible structure in the middle, the stress during non-road driving can be buffered, which can ensure the safety and stability of the vehicle. However, when a large current passes through the copper bar during vehicle use, a certain voltage will be generated at both ends of the copper bar, which will lead to a large deviation in battery sampling.

[0003] The commonly used solution in the industry is to sample each battery and copper bar, and then remove the voltage generated by the copper bar to obtain the accurate battery voltage. Such a mode has a large demand for the number of sampling channels of the analog front end (AFE chip). Generally, the maximum number of sampling channels of a single AFE chip is 16 strings. For example, in the current 48V platform system, 16 single cells are required for combination. If it is a 1P16S (16 cells) module, exactly one AFE can be used. However, common non-road vehicle power battery modules will use a 2P8S (8 cells + copper bar + 8 cells) mode, or a 3P5S (5 cells + copper bar + 5 cells + copper bar + 5 cells). Obviously, the sampling channels of one AFE are not enough to meet the sampling of all batteries and copper bars. In response to this situation, there are generally two solutions. The first one is to ignore the sampling of the flexible copper bar and use a software strategy for voltage sampling compensation. However, this solution has a large error and has gradually fallen out of use. The second one is to add an AFE chip to sample the extra copper bars and batteries, but the design scheme is complex and the cost is high.

[0004] Based on this, this application mainly expands the sampling channels of a single AFE to solve the problem of insufficient battery sampling channels caused by the connection of module copper bars. Content of the Utility Model

[0005] In order to make up for the deficiencies of the prior art, the purpose of the utility model is to provide a copper row sampling circuit for a battery power module to solve the problem of insufficient battery sampling channels caused by the connection of module copper bars.

[0006] The described copper bus sampling circuit for a battery power module includes Battery Module I, Battery Module II, a copper bus connecting Battery Module I and Battery Module II, and an AFE chip. It is characterized in that Battery Module I, the copper bus, and Battery Module II are connected in series in sequence. One end of the copper bus is connected to the positive electrode of the last battery in Battery Module I, and the other end is connected to the negative electrode of the first battery in Battery Module II. The sampling channels of the AFE chip are respectively connected to the positive and negative electrodes of each battery in Battery Module I and Battery Module II. Moreover, the negative electrode of the first battery in Battery Module I is connected to the first sampling channel of the AFE chip, and after the positive electrode of the first battery is connected to the negative electrode of the second battery, it is connected to the second sampling channel of the AFE chip, and so on. The positive electrode of the second-to-last battery in Battery Module II and the negative electrode of the last battery are connected to the same sampling channel, and the positive electrode of the last battery in Battery Module I and the negative electrode of the first battery in Battery Module II are connected to the same sampling channel.

[0007] Furthermore, the connection point between the copper bus and the positive electrode of the last battery in Battery Module I is denoted as node BAT8. Node BAT8 is connected to the GPI01 pin of the AFE chip through a first control switch; the connection point between the copper bus and the negative electrode of the first battery in Battery Module II is denoted as node BAT9-. Node BAT9- is connected to the GPI02 pin of the AFE chip through a second control switch, and node BAT9- is connected to the sampling channel VC8 of the AFE chip. The operating states of the first control switch and the second control switch are opposite. Through the first control switch and the second control switch, a single sampling channel of the AFE chip samples the last battery in Battery Module I, the copper bus, and the first battery in Battery Module II.

[0008] Furthermore, one end of the first control switch is connected to the GPI01 pin of the AFE chip, and the other end is connected in parallel with resistor R9 and diode D6. The other end of diode D6 is grounded, the other end of resistor R9 is connected in parallel with resistor R10 and the base of triode Q4. The other end of resistor R10 is grounded, the emitter of triode Q4 is grounded, and the collector of triode Q4 is connected to resistor R7; the other end of resistor R7 is connected in parallel with PMOS transistor Q3, diode D4, and resistor R6 and then connected to node BAT8. The gate of PMOS transistor Q3 is connected to resistor R7, the source is connected to node BAT8, and the drain is connected to resistor R16 and then to sampling channel VC8.

[0009] Further, one end of the second control switch is connected to the GPI02 pin of the AFE chip, and the other end is connected in parallel with a resistor R4 and a diode D3. The other end of the diode D3 is grounded. The other end of the resistor R4 is connected in parallel with a triode Q2 and a resistor R5. The other end of the resistor R5 is grounded. The base of the triode Q2 is connected to the resistor R4, the emitter is grounded, and the collector is connected to a resistor R3. The resistor R3 is connected in parallel with a PMOS transistor Q1, a diode D2, and a resistor R2 and then connected to the node BAT9-. The source of the PMOS transistor Q1 is connected to the node BAT9-, the gate is connected to the resistor R3, and the drain is connected to the sampling channel VC8 after being connected in series with a resistor R191.

[0010] Further, in the battery module I and the battery module II, each sampling channel of the AFE chip is connected in series with a resistor with a resistance value of 1 KΩ and then connected to the corresponding battery, and a capacitor and a diode are connected between adjacent sampling channels. The capacitance of the capacitor is 0.1 uF.

[0011] Compared with the prior art, the present invention has the following advantages: The circuit of the present application is simple, which reduces the cost. By designing two control switches between the adjacent resistor modules and the busbar, the busbar and its adjacent batteries can be sampled through a single sampling channel of the AFE chip without adding an AFE chip, thus avoiding the problem that it is impossible to sample all the batteries in the battery module due to the addition of the busbar connection, that is, avoiding the problem that the busbar voltage affects the sampling accuracy when using the busbar connection in the power battery module. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 is the sampling circuit diagram of the present invention;

[0013] Figure 2 is for the present invention Figure 1 partial circuit enlarged view;

[0014] Figure 3 is one of the simplified block diagrams of the circuit of the present invention;

[0015] Figure 4 is the other simplified block diagram of the circuit of the present invention;

[0016] Figure 5 is the sampling circuit diagram of the existing battery module (without busbar);

[0017] Figure 6 is the sampling circuit diagram of the existing battery module (with busbar). DETAILED DESCRIPTION OF THE EMBODIMENTS

[0018] To make those skilled in the art understand the technical solution of the present application more clearly and clearly, the present invention will be further described below with reference to the accompanying drawings.

[0019] AsFigure 1 and Figure 2 As shown in Figure 2 , a copper bar sampling circuit for a battery-powered module includes Battery Module I, Battery Module II, a copper bar connecting Battery Module I and Battery Module II, and an AFE chip. Battery Module I, the copper bar, and Battery Module II are connected in series in sequence. One end of the copper bar is connected to the positive electrode of the last battery in Battery Module I, and the other end is connected to the negative electrode of the first battery in Battery Module II. The sampling channels of the AFE chip are respectively connected to the positive and negative electrodes of each battery in Battery Module I and Battery Module II. Moreover, the negative electrode of the first battery in Battery Module I is connected to the first sampling channel of the AFE chip, and the positive electrode of the first battery and the negative electrode of the second battery are connected to the same sampling channel (i.e., the second sampling channel), and so on. The positive electrode of the penultimate battery in Battery Module II and the negative electrode of the last battery are connected to the same sampling channel, and the positive electrode of the last battery in Battery Module I and the negative electrode of the first battery in Battery Module II are connected to the same sampling channel.

[0020] Among them, the connection point between the copper bar and the positive electrode of the last battery in Battery Module I is denoted as Node BAT8. Node BAT8 is connected to the GPI01 pin of the AFE chip through a first control switch; the connection point between the copper bar and the negative electrode of the first battery in Battery Module II is denoted as Node BAT9-. Node BAT9- is connected to the GPI02 pin of the AFE chip through a second control switch, and Node BAT9- is connected to the sampling channel VC8 of the AFE chip; the working states of the first control switch and the second control switch are opposite. By means of the first control switch and the second control switch, a single sampling channel of the AFE chip samples the last battery in Battery Module I, the copper bar, and the first battery in Battery Module II.

[0021] One end of the first control switch is connected to the GPI01 pin of the AFE chip, and the other end is connected in parallel with resistor R9 and diode D6. The other end of diode D6 is grounded. The other end of resistor R9 is connected in parallel with resistor R10 and the base of triode Q4. The other end of resistor R10 is grounded. The emitter of triode Q4 is grounded, and the collector of triode Q4 is connected to resistor R7. The other end of resistor R7 is connected in parallel with PMOS transistor Q3, diode D4, and resistor R6 and then connected to node BAT8. The gate of PMOS transistor Q3 is connected to resistor R7, the source is connected to node BAT8, and the drain is connected to resistor R16 and then connected to sampling channel VC8. One end of the second control switch is connected to the GPI02 pin of the AFE chip, and the other end is connected in parallel with resistor R4 and diode D3. The other end of diode D3 is grounded. The other end of resistor R4 is connected in parallel with triode Q2 and resistor R5. The other end of resistor R5 is grounded. The base of triode Q2 is connected to resistor R4, the emitter is grounded, and the collector is connected to resistor R3. Resistor R3 is connected in parallel with PMOS transistor Q1, diode D2, and resistor R2 and then connected to node BAT9-. The source of PMOS transistor Q1 is connected to node BAT9-, the gate is connected to resistor R3, and the drain is connected in series with resistor R191 and then connected to sampling channel VC8. In battery module I and battery module II, each sampling channel of the AFE chip is connected in series with a resistor with a resistance value of 1 KΩ and then connected to the corresponding battery, and a capacitor and a diode are connected between adjacent sampling channels. The capacitance of the capacitor is 0.1 uF.

[0022] It can be understood that in this application, the first control switch and the second control switch are set between both ends of the copper bar and the adjacent batteries to realize the sampling of the end battery of battery module I, the copper bar, and the first battery of battery module II by a single sampling channel of the AFE chip. The specific sampling strategy is as follows:

[0023] When the first control switch is at a high level (i.e., the first control switch is closed and the second control switch is open), triode Q4 conducts. When triode Q4 conducts, the voltage of node BAT8 is divided by resistors R6 and R7 to control PMOS transistor Q3 to conduct. After PMOS transistor Q3 conducts, the sampling voltage between sampling channel VC7 and sampling channel VC8 of the AFE chip is the voltage of the end battery of battery module I. Since the second control switch is open, both PMOS transistor Q1 and triode Q2 do not work. Therefore, the sampling voltage between sampling channel VC8 and sampling channel VC9 of the AFE chip is the sum of the copper bar voltage and the voltage of the first battery of battery module II, as Figure 3 shown.

[0024] When the second control switch is at a high level (i.e., the second control switch is off and the first control switch is on), the triode Q2 conducts. When the triode Q2 conducts, the voltage at node BAT9- is divided by resistor R2 and resistor R3 to control the PMOS transistor Q1 to conduct. After the PMOS transistor Q1 conducts, the sampling voltage between the sampling channels VC8 and VC9 of the AFE chip is the voltage of the first cell at the head end of battery module II; since the first control switch is on, the PMOS transistor Q3 and the triode Q4 do not work, and the sampling voltage between the sampling channels VC7 and VC8 of the AFE chip is the sum of the voltage of the copper busbar and the voltage of the last cell of battery module I, as Figure 4 shown.

[0025] Through the above two control switches (the first control switch and the second control switch), and through the above sampling strategy, it is possible to accurately sample the voltages of the last cell of battery module I, the copper busbar, and the first cell of battery module II respectively, and have no impact on other sampling channels. Therefore, the present invention mainly expands the sampling channels of a single AFE chip, solving the problem of insufficient battery sampling channels caused by the connection of battery modules through copper busbars. Embodiment

[0026] Currently, the power battery 48V platform system requires 16 single cells to be combined. Generally, the maximum number of sampling channels of a single AFE chip in the industry is 16 strings. If it is 1P16S (16 cells), the sampling channels for battery voltage are as Figure 5 shown. However, currently, non-road vehicle power battery modules often use the 2P8S (8 cells + copper busbar + 8 cells) mode, or the 3P5S (5 cells + copper busbar + 5 cells + copper busbar + 5 cells)). Obviously, the sampling channels of one AFE chip are not enough to meet the sampling of all batteries and copper busbars. Here, taking the 2P8S (8 cells + copper busbar + 8 cells) mode as an example, as Figure 6 can be seen, when the non-road vehicle power module uses a copper busbar connection, in order to sample the voltage of each cell more accurately, the voltages at both ends of the flexible copper busbar will also be sampled. However, due to the problem of the number of AFE sampling channels, there is no channel to sample the voltage of the 16th cell.

[0027] Continue to refer to Figure 1 and Figure 2It can be known that for a copper bus sampling circuit of a battery power module, an AFE chip is used to sample 2P8S (8 batteries + copper bus + 8 batteries). The negative electrode of the first battery (i.e., the first battery at the head end of battery module I) (denoted as node BAT0) is connected to the sampling channel VC0 of the AFE chip. The positive electrode of the first battery is connected to the negative electrode of the second battery (denoted as node BAT1) and then connected to the sampling channel VC1 of the AFE chip. And so on. After the positive electrode of the seventh battery is connected to the negative electrode of the eighth battery (denoted as node BAT7), it is connected to the AFE sampling channel VC7. After a copper bus is connected between the positive electrode of the eighth battery (i.e., the last battery of battery module I) and the negative electrode of the ninth battery (i.e., the first battery of battery module II), it is connected to the sampling channel VC8 of the AFE chip. The positive electrode of the sixteenth battery (i.e., the last battery of battery module II) is connected to the sampling channel VC16 of the AFE chip.

[0028] In this application, a first control switch GPI01 and a second control switch GPI02 are arranged between the sampling channel VC7 and the sampling channel VC8. The connection point of the copper bus and the positive electrode of the eighth battery is denoted as node BAT8. Node BAT8 is connected to the GPI01 pin of the AFE chip through the first control switch GPI01. The connection point of the copper bus and the negative electrode of the ninth battery is denoted as node BAT9-. Node BAT9- is connected to the GPI02 pin of the AFE chip through the second control switch GPI02, and node BAT9- is connected to the sampling channel VC8 of the AFE chip. The working states of the first control switch GPI01 and the second control switch GPI02 are opposite. Through the first control switch GPI01 and the second control switch GPI02, the sampling channel VC8 of the AFE chip is coordinated with the sampling channels VC7 and VC9 to sample the eighth battery, the copper bus, and the ninth battery.

[0029] One end of the first control switch GPI01 is connected to the GPI01 pin of the AFE chip, and the other end is connected in parallel with resistor R9 and diode D6. The other end of diode D6 is grounded. The other end of resistor R9 is connected in parallel with resistor R10 and the base of transistor Q4. The other end of resistor R10 is grounded. The emitter of transistor Q4 is grounded, and the collector of transistor Q4 is connected to resistor R7. The other end of resistor R7 is connected in parallel with PMOS transistor Q3, diode D4, and resistor R6 and then connected to node BAT8. The gate of PMOS transistor Q3 is connected to resistor R7, the source is connected to node BAT8, and the drain is connected to resistor R16 and then connected to sampling channel VC8. One end of the second control switch GPI02 is connected to the GPI02 pin of the AFE chip, and the other end is connected in parallel with resistor R4 and diode D3. The other end of diode D3 is grounded. The other end of resistor R4 is connected in parallel with transistor Q2 and resistor R5. The other end of resistor R5 is grounded. The base of transistor Q2 is connected to resistor R4, the emitter is grounded, and the collector is connected to resistor R3. Resistor R3 is connected in parallel with PMOS transistor Q1, diode D2, and resistor R2 and then connected to node BAT9-. The source of PMOS transistor Q1 is connected to node BAT9-, the gate is connected to resistor R3, and the drain is connected in series with resistor R191 and then connected to sampling channel VC8. Among them, a resistor with a resistance value of 1KΩ is connected in series between each battery node and the corresponding sampling channel VC1 (for example: a resistor R92 is connected between node BAT0 and sampling channel VC0, and the resistance value of resistor R92 is 1KΩ), and a capacitor and a diode are connected between adjacent sampling channels. The capacitance of the capacitor is 0.1uF (for example, capacitor C39 and diode D20 are connected in parallel between sampling channel VC0 and sampling channel VC1, capacitor C32 and diode D12 are connected in parallel between sampling channel VC1 and sampling channel VC2. The capacitances of capacitor C40 and capacitor C32 are both 0.1uF, and diodes D12 and D20 are both BZT52B7V5JS-TP).

[0030] Continue to refer to Figure 3 It can be known that when the first control switch GPI01 is closed and conducting, and the second control switch GPI02 is open, the sampling voltage between sampling channels VC7 and VC8 of the AFE chip is the voltage of the eighth battery, and the sampling voltage between sampling channels VC8 and VC9 of the AFE chip is the sum of the busbar voltage and the voltage of the ninth battery.

[0031] Continue to refer to Figure 4 It can be known that when the first control switch GPI01 is open and the second control switch GPI02 is closed and conducting, the sampling voltage between sampling channels VC7 and VC8 of the AFE chip is the sum of the voltage of the eighth battery and the busbar voltage, and the sampling voltage between sampling channels VC8 and VC9 of the AFE chip is the voltage of the ninth battery.

[0032] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present utility model and are not intended to limit them; although the present utility model has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present utility model.

Claims

1. A copper bus sampling circuit for a battery-powered module, comprising a battery module I, a battery module II, a copper bus connecting the battery module I and the battery module II, and an AFE chip, characterized in that, The battery module I, the copper bar, and the battery module II are connected in series in sequence. One end of the copper bar is connected to the positive electrode of the last battery of the battery module I, and the other end is connected to the negative electrode of the first battery of the battery module II. The sampling channels of the AFE chip are respectively connected to the positive and negative electrodes of each battery in the battery module I and the battery module II. Moreover, the negative electrode of the first battery of the battery module I is connected to the first sampling channel of the AFE chip. After the positive electrode of the first battery is connected to the negative electrode of the second battery, it is connected to the second sampling channel of the AFE chip, and so on. The positive electrode of the second-to-last battery of the battery module II and the negative electrode of the last battery are connected to the same sampling channel. The positive electrode of the last battery of the battery module I and the negative electrode of the first battery of the battery module II are connected to the same sampling channel.

2. The copper bus sampling circuit of a battery-powered module according to claim 1, characterized in that, The connection point between the copper bar and the positive electrode of the last battery of the battery module I is denoted as node BAT8. Node BAT8 is connected to the GPI01 pin of the AFE chip through the first control switch; the connection point between the copper bar and the negative electrode of the first battery of the battery module II is denoted as node BAT9-. Node BAT9- is connected to the GPI02 pin of the AFE chip through the second control switch, and node BAT9- is connected to the sampling channel VC8 of the AFE chip; the operating states of the first control switch and the second control switch are opposite. Through the first control switch and the second control switch, the single sampling channel of the AFE chip samples the last battery of the battery module I, the copper bar, and the first battery of the battery module II.

3. The copper bar sampling circuit of a battery-powered module according to claim 2, wherein One end of the first control switch is connected to the GPI01 pin of the AFE chip, and the other end is connected in parallel with the resistor R9 and the diode D6. The other end of the diode D6 is grounded. The other end of the resistor R9 is connected in parallel with the resistor R10 and the base of the triode Q4. The other end of the resistor R10 is grounded. The emitter of the triode Q4 is grounded, and the collector of the triode Q4 is connected to the resistor R7; the other end of the resistor R7 is connected in parallel with the PMOS transistor Q3, the diode D4, and the resistor R6 and then connected to the node BAT8. The gate of the PMOS transistor Q3 is connected to the resistor R7, the source is connected to the node BAT8, and the drain is connected to the resistor R16 and then connected to the sampling channel VC8.

4. The copper bus sampling circuit of a battery-powered module according to claim 3, characterized in that, One end of the second control switch is connected to the GPI02 pin of the AFE chip, and the other end is connected in parallel with the resistor R4 and the diode D3. The other end of the diode D3 is grounded. The other end of the resistor R4 is connected in parallel with the triode Q2 and the resistor R5. The other end of the resistor R5 is grounded. The base of the triode Q2 is connected to the resistor R4, the emitter is grounded, and the collector is connected to the resistor R3. The resistor R3 is connected in parallel with the PMOS transistor Q1, the diode D2, and the resistor R2 and then connected to the node BAT9-. The source of the PMOS transistor Q1 is connected to the node BAT9-, the gate is connected to the resistor R3, and the drain is connected in series with the resistor R191 and then connected to the sampling channel VC8.

5. The copper bus sampling circuit of a battery-powered module according to claim 4, wherein In the battery module I and the battery module II, each sampling channel of the AFE chip is connected to the corresponding battery after being connected in series with a resistor with a resistance value of 1 kΩ, and a capacitor and a diode are connected between adjacent sampling channels, and the capacitance of the capacitor is 0.1 μF.

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